| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 318400340 | Electromotive force sensor (e.g., back or counter EMF sensor, etc.) | 79 |
| 20130026962 | METHODS AND SYSTEMS FOR CONTROLLING A MOTOR - A control system for a motor includes an inverter coupled to the motor. The control system further includes a microcontroller coupled to the inverter. The microcontroller includes a processor programmed to measure an input voltage and acquire a back EMF voltage of the motor. The processor is also programmed to control the inverter to regulate the motor voltage based on the input voltage and the back EMF voltage to facilitate controlling the motor. | 01-31-2013 |
| 20090243526 | DEVICE AND METHOD FOR DETECTING BACK ELECTROMOTIVE FORCE PHASE AND DEVICE AND METHOD FOR CONTROLLING EXCITATION - In a back electromotive force phase detecting device, a timing generating unit generates a timing signal indicating a start timing, an intermediate timing and an end timing of a 180-degree electrical angle period in a detection target phase, from an excitation pulse signal. A difference calculating unit receives the timing signal, and calculates a difference between a total PWM control period of the detection target phase during a first-half 90-degree period, and a total PWM control period of the detection target phase during a second-half 90-degree period. In an excitation control device, a control unit changes the capability of driving a motor based on an output of the back electromotive force phase detecting device. | 10-01-2009 |
| 20110187303 | SENSOR-TYPE BRUSHLESS DC MOTOR - Disclosed herein is a sensorless-type brushless DC motor, including: a magnet provided in a rotor; and a stator formed by winding a coil on a core stacked with sheets while facing the magnet, wherein the position of the rotor is detected by detecting back electromotive force induced to the coil, the back electromotive force includes a harmonic component 5 times higher than a fundamental wave, and an amplitude ratio of the 5-times harmonic wave to the fundamental wave is set to be 1% or more. Further, the sensorless-type brushless DC motor can prevent a failure in detecting an initial position of the rotor by controlling a waveform of the back electromotive force and minimize an increase of a starting time. | 08-04-2011 |
| 20130043818 | SOFT-SWITCHING CONTROL CIRCUIT FOR DC MOTOR - A soft switching control circuit for a DC motor is provided. The soft switching control circuit has an absolute value generating circuit, a threshold voltage generating circuit, and a comparing circuit. The absolute value generating circuit outputs an absolute value signal according to a pair of Hall signals from the DC motor. The threshold voltage generating circuit receives a detected state signal and at least an end voltage of a coil of the DC motor for determining a current on the coil at an actual state change time defined by the detected state signal. According to the determination, the threshold voltage generating circuit outputs a threshold voltage with an adjusted voltage level. The comparing circuit compares the absolute value signal and the threshold voltage so as to generate a state change adjusting signal for modifying the actual state change time. | 02-21-2013 |
| 20090195201 | METHOD FOR CONTROLLING AN AC ELECTRONIC MOTOR AND DEVICE FOR CARRYING OUT SAID METHOD - The invention relates to electric engineering, in particular to methods for controlling an ac electronic motor. The inventive control method consists in starting and rotating a rotor upon EMF signals in current-free sections of an armature winding, in converting the EMF signals into discrete logical level signals by a normaliser, in detecting switching points by means of a microcontroller and in displacing said points according to a load current quantity, the rotor speed of rotation and the inductance of the armature winding sections, wherein the switching points are calculated and displaced with respect to bridging times of the free sections EMF whose voltage levels are different from zero. The inventive device is characterised in that it comprises a reference level displacing unit ( | 08-06-2009 |
| 20090009115 | Brushless Dc-Motor - According to the invention, a DC-motor ( | 01-08-2009 |
| 20100066287 | SYSTEMS AND METHODS FOR DETECTING POSITION FOR A BRUSHLESS DC MOTOR - A system for determining a commutation state for a brushless DC motor includes a controller configured to control current that is applied to drive each of a plurality of phases of the motor. A time delay system is configured to measure, for a given commutation state, a time delay from when a voltage associated with a driven phase of the plurality of phases crosses a predetermined threshold and a voltage associated with a floating phase of the plurality of motor phases crosses the predetermined threshold. Logic is configured to determine the commutation state for the motor based on the measured time delay. | 03-18-2010 |
| 20100001673 | SENSORLESS TECHNOLOGY, ESTIMATION OF SAMPLED BACK EMF VOLTAGE VALUES AND/OR THE SAMPLED INDUCTANCE VALUES BASED ON THE PULSE WIDTH MODULATION PERIODS - The methods and devices provided herein include methods and devices for controlling a permanent magnet motor. In one implementation, a method is provided that allows for the determination of the values of the phase back EMF voltage and of the phase inductances while the phases are powered with a PWM (Pulse Width Modulation) controlled current and/or voltage. | 01-07-2010 |
| 20130069575 | BRUSHLESS MOTOR DRIVING APPARATUS AND BRUSHLESS MOTOR DRIVING METHOD - A brushless motor driving apparatus that rotates and drives a brushless motor, which has a plurality of coils, by switching energization modes corresponding to phases of the brushless motor, sequentially switches the energization modes based on a non-energized phase voltage and a voltage threshold. Also, the brushless motor driving apparatus regulates an upper threshold for energization amount based on the voltage threshold and a change in the non-energized phase voltage at timing of switching the energization mode. | 03-21-2013 |
| 20130113403 | METHOD FOR CONTROL OF SYNCHRONOUS ELECTRICAL MOTORS - Method for control of synchronous electrical motors that enables determining the instantaneous motor load angle and rotor speed without using rotor position sensors. The method is realized with solving the set of differential equations that govern the currents in the stator windings of the motor for the time intervals between each two consecutive crossings of the currents in the windings of their set values and deriving relationships between the induced in the windings back-electromotive force voltages and the parameters of the Pulse Width Modulation. The parameters of the Pulse Width Modulation are measured and stored in a memory and based on the derived relationships the values of the back-electromotive force voltages are calculated continuously in time. From the values of the back-electromotive force voltages the motor load angle and rotor speed are calculated and used as feedback signals for the closed-loop control of the motor. | 05-09-2013 |
| 20090009116 | Energization timing determination circuit and determination method for energization timing of motor - An energization timing determination circuit corrects a shift contained in a position signal outputted from a position detecting means and supplies energization timing appropriate to drive a motor. A correction amount computation unit computes detection intervals obtained based on position signals outputted from filters, comparators, and a position detection unit during one cycle of electrical angle. The correction amount computation unit thereby determines the duty shift length α and phase shift length β of the position signals. A control circuit corrects energization timing based on the position signals according to the detected shift lengths. | 01-08-2009 |
| 20090315495 | SENSORLESS CONTROL APPARATUS OF SYNCHRONOUS MOTOR - A PWM modulation unit modulates a three-phase voltage instruction, which is input, on the basis of a PWM method, and outputs a gate signal to each phase switching element of an inverter. A high-frequency component arithmetic unit calculates, at each time of switching of the inverter, a high-frequency component of a current occurring due to a voltage which is determined by the PWM modulation unit and is output from the inverter. An index arithmetic unit calculates, as an index R proportional to a rotational phase angle estimation error, from the high-frequency component of the current. A rotational phase angle estimation unit executes an estimation arithmetic operation of the rotational phase angle by using the index R. The invention provides a synchronous motor sensorless control apparatus which enables stable driving with simple adjustment, and does not cause an extreme increase in amount of arithmetic calculations. | 12-24-2009 |
| 20110285337 | CONTROL DEVICE OF A SYNCHRONOUS MOTOR - A control device of a synchronous machine is disclosed. The control device includes an inverter configured to provide an output current to a synchronous machine. A controller configured to control the output current and to estimate a voltage command, at least in part, by using pulse width modulation to choose a non-zero vector at a time when the inverter is not driving the synchronous machine with the output current. The estimating the voltage command is performed without using a zero vector. A phase angle and angular velocity estimating section configured to estimate a phase angle and an angular velocity of a rotor of the synchronous machine based, at least in part, on an inductance value, an induction voltage value, the voltage command, and the output current. The controller is further configured to control the output current based, at least in part, on the phase angle and the angular velocity. | 11-24-2011 |
| 20100201297 | METHOD FOR CONTROL OF SYNCHRONOUS ELECTRICAL MOTORS - Method for control of synchronous electrical motors that enables determining continuously in time the motor load angle and speed of rotation without using additional rotor position sensors. The method is realized with solving the set of differential equations that govern the currents and the voltages in the stator windings of the motor for the time intervals between each two consecutive reachings of the currents in the windings to their set values and deriving relationships between the induced in the windings back-electromotive force voltages and the parameters of the Pulse Width Modulation. The parameters of the Pulse Width Modulation are measured and stored in memory and based on the derived relationships the values of the back-electromotive force voltages are calculated at every moment in time and from these values subsequently the values of the load angle and the angular rotor speed of the motor are calculated. | 08-12-2010 |
| 20090160383 | ELECTRIC MACHINE - A two-phase electric motor includes first and second coil groups and a magnet group. In the magnet group, N poles and S poles are disposed alternatively opposite the first and second coil groups. The first and second coil groups are disposed at positions that are out of phase with each other by an odd multiple of π/2 in electrical angles. The coils of the first and second coil groups have substantially no magnetic material cores, and the electric motor has substantially no magnetic material yoke for forming a magnetic circuit. | 06-25-2009 |
| 20090167226 | Method for Controlling a Direct Current Brushless Motor, and Control Circuit - A method for controlling a direct current (DC) brushless motor, and a control circuit thereof are provided. The DC brushless motor is sensorless. In response to a digital output signal that is applied to drive the direct current brushless motor, detection of a back electromotive force (BEMF) is ceased in a predetermined time interval, so as to avoid detecting erroneous BEMF and keep normal operation of the direct current brushless motor. | 07-02-2009 |
| 20100188033 | SENSORLESS OPTIMUM TORQUE CONTROL FOR HIGH EFFICIENCY IRONLESS PERMANENT MAGNET MACHINE - Embodiments of the present invention permit the optimization of torque control of a permanent magnet machine including obtaining instantaneous terminal voltages of the machine, transforming the instantaneous terminal voltages to a zero direct axis voltage and a non-zero quadrature axis voltage, using a mathematical transformation, regulating the electrical frequency of the permanent-magnet machine such that the zero direct-axis voltage is adjusted to have a value of zero, determining a non-final electrical angle of the permanent-magnet machine by applying an integrator to the regulated electrical frequency of the machine, determining a final electrical angle of the of the machine by integrating the non-final electrical angle and an electrical angle from a previous calculation cycle, and regulating the current vector of the machine such that the current vector is perpendicular to the final electrical angle of the machine, thereby optimizing the torque of the machine. | 07-29-2010 |
| 20090079374 | Self Starting Method and an Apparatus for Sensorless Commutation of Brushless Dc Motors - A method and an apparatus for determining rotor position information of a Brushless DC motor using the resultant voltage vector produced by addition of phase voltage vectors of the energised windings and the BEMF vector of the unenergised winding. This resultant voltage vector called the BEMF Space Vector rotates at same speed as the rotor and possesses rotor position information used to commutate phase windings. Phase voltage vectors for the computation of the BEMF Space Vector are obtained by referring scalar phase voltages in the electrical circuits to the magnetic axes of the magnetic circuits, since scalar and vector current magnitudes are equal. Angles that the BEMF Space Vector makes with the real axis are measured to commutate the phase windings. This technique is referred to as the De Four BEMF Space Vector Resolver, used to efficiently start the motor from rest and commutate phase windings during normal operation. | 03-26-2009 |
| 20120139464 | Synchronous reluctance motor, operating machine comprising the motor and method for controlling the motor - A synchronous reluctance motor comprises a stator ( | 06-07-2012 |
| 20100237817 | Method and Apparatus for Estimating Rotor Position in a Sensorless Synchronous Motor - The present invention provides a simple, robust, and universal position observer for use with sensorless synchronous machines. The observer may be implemented using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model of the synchronous machine. The observer may be used on any type of synchronous machine, including salient or non-salient pole machines such as a permanent magnet, interior permanent magnet, wound rotor, or reluctance synchronous machine. The observer provides low sensitivity to parameter variations and disturbances or transient conditions in the machine. In addition, no knowledge of speed is required as an input to the observer and an estimated position may be calculated using a subset of the machine parameters. | 09-23-2010 |
| 20090322269 | MOTOR CONTROL APPARATUS FOR CONTROLLING MOTOR IN ACCORDANCE WITH ROTATIONAL POSITION OF ROTOR THEREOF - The motor control apparatus includes a power supply function of supplying electric power from a power supply to a motor, a rotational position detecting function of performing detection of a rotational position of a rotor of the motor for respective phases of the motor, and outputting first rotational position data indicative of result of the detection, a control function of controlling a power supply operation of the power supply function in accordance with the first rotational position data, and an induced voltage detecting function of performing detection of induced voltages of the respective phases of the motor. The control function controls the power supply operation of the power supply function in accordance with result of the detection performed by the induced voltage detecting function when the first rotational position data are abnormal. | 12-31-2009 |
| 20090179604 | Electric Motor - An electric motor ( | 07-16-2009 |
| 20090160384 | ELECTRICAL MACHINE AND METHOD OF CONTROLLING THE SAME - An electrical machine having a stator and a rotor. The stator includes a core and a plurality of windings disposed on the core in a multiple-phase arrangement. The rotor is disposed adjacent to the stator to interact with the stator. A method of operating the motor includes applying a pulsed voltage differential to first and second terminals of the windings resulting in movement of the rotor; monitoring the back electromotive force (BEMF) of the windings to sense rotor movement; after the applying and monitoring steps, monitoring the BEMF of the windings to determine whether the rotor is rotating in a desired direction, and electrically commutating the motor when the rotor is rotating in the desired direction and zero or more other conditions exist. | 06-25-2009 |
| 20090146598 | BRUSHLESS MOTOR - A brushless motor driven by a sensorless driving circuit includes a rotating body capable of being rotated about a center axis; a rotor magnet arranged coaxially with the rotating body; a stator disposed opposite the rotor magnet; and at least one coil wound around the stator. The brushless motor is driven according to a signal containing a third harmonic component relative to a fundamental wave component in an induced electromotive force. Further, an amplitude ratio of the third harmonic component to the fundamental wave component in the induced electromotive force generated in the coil preferably is about 1% or higher. | 06-11-2009 |
| 20090108784 | Motor Control Apparatus and Motor System - In a motor control apparatus, apparatus all switching devices of all phases of an inverter are kept fixed at OFF in accordance with a value of an all-OFF control pulse signal Poff outputted by a pulse generator. The pulse generator generates at least twice a pulse causing an induced voltage detection signal Pdet to change to an H level. A terminal voltage of a motor is inputted in accordance with the value of the induced voltage detection signal Pdet. Data of the sampling round in which amplitude of the induced voltage signal is great and the signal is not in saturation is selected from the data so inputted and a rotor position is estimated. | 04-30-2009 |
| 20080224641 | Driver for a Brushless Motor and Data Reading/Writing Device Comprising a Brushless Motor Controlled by Such a Driver - A driver for a brushless motor ( | 09-18-2008 |
| 20110121770 | Method and Device for Driving a Two-Phase Brushless Motor - A method for driving a two-phase brushless motor is disclosed. The motor includes a rotator with permanent magnetism and a stator including a first coil and a second coil. The method includes activating the two-phase brushless motor, detecting an output voltage of a disabled coil of the first coil and the second coil to generate a detection result, comparing the detection result and a reference voltage to determine a commutation time point between the first coil and the second coil, generating a commutation signal according to the commutation time point, and driving the two-phase brushless motor according to the commutation time point. | 05-26-2011 |
| 20120200246 | MOTOR CONTROL METHOD AND SYSTEM AND DIGITAL SIGNAL PROCESSOR THEREOF - A digital signal processor (DSP) is operable to receive a single-phase back electromotive force signal (back-EMF) fed back from a motor and control an inverter for driving the motor based on the single-phase back-EMF signal. The DSP includes an electrical angle building module, a rotation speed control module, and a pulse width modulation control module. | 08-09-2012 |
| 20110050139 | PHASE DETECTION METHOD, PHASE DETECTING APPARATUS, SYNCHRONOUS-MOTOR CONTROL METHOD, AND SYNCHRONOUS MOTOR CONTROLLER - It is determined which of six continuous sections having different magnitude correlation of signal amplitude of each phase of an input three-phase signal a section is. Predetermined subtraction is performed between respective phases in the section, to obtain a normalized amplitude value normalized in the section, using the subtraction result. The normalized amplitude value is converted to a vector phase for one cycle based on a predetermined phase and output corresponding to the determined section. | 03-03-2011 |
| 20080315811 | System and Method for Collecting Characteristic Information of a Motor, Neural Network and Method for Estimating Regions of Motor Operation from Information Characterizing the Motor, and System and Method for Controlling Motor - A method for collecting operational parameters of a motor may include controlling the energization of a phase winding of the motor to establish an operating point, monitoring operational parameters of the motor that characterize a relationship between the energization control applied to the motor's phase winding and the motor's response to this control, and collecting information of the operational parameters for the operating point that characterizes the relationship between the applied energization control and the motor's response. The collected information characterizing the relationship between the applied energization control and the motor's response may be employed by a neural network to estimate the regions of operation of the motor. And a system for controlling the operation of motor may employ this information, the neural network, or both to regulate the energization of a motor's phase winding di-ring a phase cycle. | 12-25-2008 |
| 20110037422 | CONTROL OF ELECTRICAL MACHINES - This invention relates to the control of electrical machines and is concerned more particularly, though not exclusively, with the control of flux switching electrical machines without a mechanical shaft position sensor. An electrical machine for converting electrical energy into mechanical energy and/or mechanical energy into electrical energy, comprises a rotor having a plurality of rotor teeth; a stator having a plurality of stator teeth for rotatably receiving said rotor and having (i) at least one field magnet device for generating a first magnetomotive force between said rotor and said stator and including at least one first electrical winding, and (ii) at least one armature magnet device including at least one second electrical winding adapted to carry electrical current varying in synchronism with rotation of said rotor relative to said stator to generate a second magnetomotive force having a component transverse to said first magnetomotive force; at least one control device for controlling supply of electrical current to or from the or each said second electrical winding by applying a sequence of switching cycles wherein the electrical current in the br each said electrical winding has positive and negative conduction blocks, each of the said conduction blocks has at least two regions, including a first region and an end region; and at least one rotor position sensor device for detecting at least one electrical signal related to the rotational position of the rotor relative to the stator and induced in a respective said first or second electrical winding as a result of a current passing through a respective second or first electrical winding, wherein at least one said rotor position sensor device comprises the steps of measuring the said electrical signal during a switching cycle in the end region, and comparing the said measurement with at least one similar measurement in at least one previous switching cycle to determine if a known rotor position has been reached. | 02-17-2011 |
| 20110316463 | CURRENT SOURCE INVERTER DEVICE - Disclosed is a current source inverter device which controls the power factor in an arbitrarily configurable manner without a magnetic pole position detector. The device is provided with a current source inverter; a motor supplied with alternating current power from the current source inverter; and a control means which detects the terminal voltage of the motor, calculates the motor's internal induced voltage and the motor current that flows in the motor based on the detected terminal voltage, and controls the current source inverter. The control means calculates the phase difference (θc) between the terminal voltage and the motor current, the phase difference (θx) between the motor current and the internal induced voltage, and the phase difference (θv) between the terminal voltage and the internal induced voltage. An adjustment angle (θα), which is the error in the phase difference between the motor current and the internal induced voltage when the set value of the phase difference (θx) is θy, is obtained from the conditional equation θα=θv−θy−θc. | 12-29-2011 |
| 20110012547 | System and Method for a High Efficiency Remote Three Phase Fan Commutation Integration Control in an Information Handling System - An information handling system includes a three phase brushless direct current motor and a motherboard which in turn includes a drive circuit. The three phase brushless direct current motor is configured to rotate a cooling fan in the information handling system based on a control signal. The drive circuit is connected to the three phase brushless direct current motor, and the drive circuit is configured to adjust the control signal sent to the three phase brushless direct current motor based on a back electromagnetic flux signal. | 01-20-2011 |
| 20120074887 | Back EMF Measuring Method for Multi-Phase BLDC Motor - A back EMF measuring method for multi-phase BLDC motor is proposed, which includes a driving process and a measuring process. The driving process energizes a plurality of phase windings of a detected motor by driving signals generated by a computing unit to rotate a rotor of the detected motor to a predetermined speed. The measuring process selects one of the phase windings as a target phase winding, continuously sends the driving signals to the phase windings other than the target phase winding but stops the driving signal sent to the target phase winding by the computing unit, and measures the back EMF of the target phase winding by a signal sensing unit. | 03-29-2012 |
| 20100270960 | METHOD AND CIRCUIT FOR PRODUCING ROTOR POSITION SIGNALS AND FOR THE COMMUTATION OF BRUSHLESS DIRECT-CURRENT MOTORS, WITHOUT USING SENSORS - A method and a circuit are provided for the commutation of brushless direct-current motors (BLDC motors), without using sensors, and especially to a method and a circuit for producing rotor position signals, without using sensors, for the commutation of brushless direct-current motors. In the method and the circuit Hall sensor signals are emulated without sensors and rotor position signals free of disturbing pulses and with a correct phase position are generated from said signals. The rotor position signals can be used to carry out a reliable, sensor-free commutation. | 10-28-2010 |
| 20100072930 | NEGATIVE SEQUENCE CARRIER SIGNAL CONTROLLER - A negative sequence feedback circuit is connected to monitor and minimize unbalances in a high-frequency ac carrier signal provided to a motor/load for the purpose of detecting rotor position. The negative sequence feedback circuit detects unbalances in the high-frequency ac carrier signal and generates negative sequence feedback. The feedback is combined with command signals used to generate the high-frequency ac carrier signal, and the combination of the command signals with the negative sequence feedback is provided to an inverter for generation of the high-frequency ac carrier signal, wherein the negative sequence feedback reduces unbalances in the resulting high-frequency ac carrier signal such that a balanced high-frequency carrier signal is provided to the motor/load. | 03-25-2010 |
| 20120268050 | Method and Apparatus for Estimating Rotor Position in a Sensorless Synchronous Motor - The present invention provides a simple, robust, and universal position observer for use with sensorless synchronous machines. The observer may be implemented using an equivalent EMF model of a synchronous machine or, alternately, using a sliding mode controller based on the equivalent EMF model of the synchronous machine. The observer may be used on any type of synchronous machine, including salient or non-salient pole machines such as a permanent magnet, interior permanent magnet, wound rotor, or reluctance synchronous machine. The observer provides low sensitivity to parameter variations and disturbances or transient conditions in the machine. In addition, no knowledge of speed is required as an input to the observer and an estimated position may be calculated using a subset of the machine parameters. | 10-25-2012 |
| 20120086375 | MOTOR CONTROL DEVICE - Problems to be Solved | 04-12-2012 |
| 20120286714 | ROTOR POSITION DETECTING APPARATUS - A rotor position detecting apparatus includes a PWM control portion controlling a switching element included in an inverter by a PWM signal having a predetermined frequency, a determination portion determining a magnitude correlation at least two times between a reference voltage specified beforehand and a terminal voltage of each terminal included in a three-phase motor in a state where the terminal voltage corresponds to one cycle of the PWM signal, and a detection portion detecting a position of a rotor of the three-phase motor based on a determination result of the determination portion. | 11-15-2012 |
| 318400350 | With zero-crossing detection (e.g., polarity reversal, etc.) | 40 |
| 20130033212 | SENSORLESS BLDC MOTOR CONTROL BY COMPARING INSTANTANEOUS & AVERAGE BEMF VOLTAGES - Sensorless driving of a brushless DC (BLDC) motor includes detecting a zero crossing time from back electromotive force (BEMF) voltage of the BLDC motor. An instantaneous BEMF voltage and an average BEMF voltage are compared to detect the crossover time, which can be used to change the commutation switching sequence. Since the average BEMF voltage differs for odd and even steps of the commutation switching sequence, average BEMF voltages are calculated separately for odd and even sequences and compared to instantaneous BEMF voltages to detect crossover points for the odd and even sequences. The times to commutations for the odd and even sequences are averaged to provide an average time to the next commutation cycle. The average time can be scaled by a reduction factor to reduce the effects of measurement noise. | 02-07-2013 |
| 20130038261 | Sensor-Less Driving Method of Permanent Magnet AC Motor - A permanent-magnet AC motor comprises a motor and a controller coupled to the motor. The motor includes a winding. The controller includes a drive model configured to provide a drive current. Waveform of the drive current is spatially symmetrical. The winding has a waiting zone having electrical angle of 30° and a driving zone having electrical angle of 150° in each half electrical cycle when the motor is in operation. The driving zone is equally divided into five driving sub-zones. | 02-14-2013 |
| 20130038260 | METHOD AND APPARATUS FOR DYNAMICALLY ADJUSTING A DEAD TIME OF BRUSHLESS DIRECT CURRENT MOTOR DURING A PHASE CHANGE - A method and apparatus for dynamically adjusting a dead time of a BLDC motor during a phase change detect the winding current of the BLDC motor during the dead time, and terminate the dead time when the winding current is detected to be substantially or close to zero. Thus, the method and apparatus can optimize the dead time and switch the BLDC motor between two phases at a zero-current point, without reducing the maximum rotation speed of the BLDC motor. | 02-14-2013 |
| 20120326647 | ZERO-CROSSING DETECTION CIRCUIT AND COMMUTATION DEVICE USING THE ZERO-CROSSING DETECTION CIRCUIT - A zero-crossing detection circuit and a commutation device using the zero-crossing detection circuit are provided. The zero-crossing detection circuit is adapted into a three-phase brushless DC (direct current) motor with first to third coils. One terminal of each of the first to third coils is electrically coupled together with each other. The detection circuit comprises a first selection circuit, a second selection circuit and a comparator. The first selection circuit and the second selection circuit are both electrically coupled to another terminals of the first to third coils, to obtain first to third terminal voltages, and output one of the first to third terminal voltages according to a selection signal. The comparator is configured for comparing an output of the first selection circuit and an output of the second selection circuit, to output a comparing result. | 12-27-2012 |
| 20090066278 | STEPPING MOTOR DRIVE AND STEPPING MOTOR DRIVING METHOD - In a drive of a stepping motor, an electromotive force is generated on the coil of a motor with a sinusoidal wave having the same period as an energization period by smoothly rotating a rotor with microstep driving, and an induced power is stably detected by detecting the electromotive force at the zero cross of driving current. The detection around the current zero cross makes it possible to shorten a detection section, form a driving waveform with few distortions, and perform driving with a driving waveform as in an ordinary micro step. Thus a circuit is provided which is aimed at reducing noise, vibrations, and loss of synchronization, and increasing current consumption efficiency in the determination of stop. | 03-12-2009 |
| 20090153086 | MOTOR DRIVE APPARATUS - The present invention provides a motor drive apparatus which improves a trade-off relation between a stable position detection and noise at its driving. A sensorless drive operation circuit calculates by operation a zero cross point (point p) of a voltage of a position detection phase at the next interval, using time information measured based on an output signal from a comparison circuit at the previous interval and the present interval. After the point p has been calculated, points a and b are detected by interrupting a predetermined time drive current. | 06-18-2009 |
| 20090096397 | RELATING TO DRIVING BRUSHLESS DC (BLDC) MOTORS - In a three phase BLDC motor the rotor position is monitored by detecting the zero crossing points of the induced back EMF signals BEMF_U, BEMF_V, BEMF_W in the phase windings U, V, W. As they are illustrated, the back EMF signals are substantially sinusoidal but they may in other situations be substantially trapezoidal. The three back EMF signals are 120° out of phase with each other. In order to accurately monitor the back EMF in a phase winding, the driving waveform for each phase U, V, W includes an undriven period P close to the expected zero crossing point. The period P can be a preset part of the driving waveform or can be an interruption of the normal driving waveform in response to suitable interrupt signals. In order to determine the zero crossing points of each back EMF signal, two (or more) samples of the back EMF are taken during the undriven period P and used to interpolate the back EMF signal to determine the zero crossing point. | 04-16-2009 |
| 20110260665 | POSITIONAL RECOGNITION USING BEMF ZERO CROSSOVER RECOGNITION OF A ROTOR OF AN ELECTRONICALLY COMMUTATED ELECTRIC MACHINE WITH TWO COIL SECTIONS OF DIFFERENT INDUCTANCES - The invention relates to a method for positional recognition of a rotor of an electronically commutated electric machine, in particular an electric motor, in which a zero crossover of a voltage induced in a coil section of the rotor or stator is used for positional recognition. According to the invention, to determine the zero crossover the coil section is briefly powered down. A rotor/stator is used, comprising at least two coil sections, one of which has a lower inductance relative to the other one, and preferably only the coil section with the lower inductance is used for the positional recognition. | 10-27-2011 |
| 20080211440 | MEASUREMENT OF SPEED AND DIRECTION OF COASTING PERMANENT MAGNET SYNCHRONOUS MOTOR - A method for determining the speed of rotation of an unpowered, coasting electric motor, driven, when powered, by an electronic inverter, and without activating switches of the inverter. The steps include determining an electrical frequency of a back emf signal generated at a terminal of the motor or switching node of the inverter when the motor is coasting and determining the mechanical motor frequency and thus speed of rotation by dividing the electrical frequency by the number of motor pole pairs. | 09-04-2008 |
| 20100102766 | Brushless, Three Phase Motor Drive - A control method for a sensor-less, brushless, three-phase DC motor. A pulse-width modulation (PWM) duty cycle may be calculated. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. The delta zero crossing error may be multiplied by a first constant representing electromechanical properties of the motor to produce a representation of an angular velocity. One or more time values may be generated based on the representation of the angular velocity. Operation of the motor may be controlled based on the one or more time values and the PWM duty cycle. | 04-29-2010 |
| 20090033263 | METHOD AND RELATED CIRCUIT FOR DRIVING A SENSORLESS BRUSHLESS MOTOR - A method of driving a sensorless brushless motor in PWM mode includes tristating a winding during a time window for detecting a zero-cross of the back electromotive force induced in the winding by rotation of a rotor, monitoring voltage of the tristated winding during an unmasked portion of the time window, and detecting during the time window a zero-cross event of the induced back electromotive force. The method includes verifying whether the zero-cross event occurred during the unmasked portion, modifying for the next cycle the duration of the time window and/or of the unmasked portion thereof based upon the verification, defining a safety interval in the unmasked time window, modifying the duration of the time window and/or of the unmasked portion thereof depending on whether the zero-cross event has been detected during the safety interval. | 02-05-2009 |
| 20100201298 | ELECTRIC DRIVE AND METHOD FOR CONTROLLING IT - An electric drive ( | 08-12-2010 |
| 20090009117 | Brushless Motor Control Apparatus and Control Method and Motor System - A brushless motor control apparatus includes a mask processing unit to which digital induced voltage signal is input, a energizing current timing generation processing unit, a pulse width detection unit, and an advance angle correction unit for performing advance angle correction. The pulse width detection unit measures pulse width of spike voltage, and the advance angle correction unit calculates the correction to the advance angle according to the length of this pulse width. The energizing current timing generation processing unit takes half the value obtained after subtracting the correction value from the edge interval of the position detection signal generated in the mask processing unit as the advance angle. | 01-08-2009 |
| 20120068649 | BACK-EMF DETECTION FOR MOTOR CONTROL - Systems, methods, and other embodiments associated with back-EMF detection for motor control are described. In an embodiment, an apparatus includes a drive circuit configured to apply excitation signals to respective inputs of a motor, a signal inhibit circuit configured to convey a signal to inhibit application of the excitation signals during an interval, and a measuring circuit configured to measure a back-electromotive force (EMF) signal crossing a reference signal during the interval. | 03-22-2012 |
| 20110221371 | ACCURACY OF ROTOR POSITION DETECTION RELATING TO THE CONTROL OF BRUSHLESS DC MOTORS - During operation of a 3 phase BLDC motor it is driven by use of a PWM waveform applied to one of the driven phase (curve a). The other driven phase is connected thereto but no driving signal is applied (curve b). The third phase is left floating (curve c). This allows the back EMF in the third phase to be monitored for the purpose of determining rotor position by detection of zero crossing points. The rapid switching of the PWM pulses causes ringing in the back EMF signal indicated for one pulse by the ringed portions | 09-15-2011 |
| 20090289588 | APPARATUS AND METHOD FOR DRIVING A MOTOR - A sampling circuit samples, while running a motor at a predetermined rotational speed, over a predetermined period a back electro-motive force induced at one end of at least one phase coil, with one end of each phase coil of the motor being brought to a high impedance. A waveform data generating circuit holds as waveform data SIN the back electro-motive force beforehand sampled by the sampling circuit. A PWM signal generating circuit sequentially reads the waveform data SIN from the waveform data generating circuit to generate a PWM signal Spwm, the pulse width of which is modulated. | 11-26-2009 |
| 20100181953 | Controller and MCU chip for controlling 3-phase brushless DC motor - The present invention discloses a 3-phase brushless DC motor controller, which comprises: a unit for generating a PWM signal; an ADC for converting a back electromotive force (BEMF) signal from an analog form into a digital form; a synchronization and extraction unit operating in synchronization in part with the PWM signal for extracting the digital BEMF signal to obtain a corresponding ZCP signal; and a unit for judging whether a commutation operation is to be performed according to a change of the corresponding ZCP signal. Await instruction and a delay instruction help to accurately acquire the digital BEMF signal. | 07-22-2010 |
| 20100019710 | Method and device for determining the position of a rotor of a brushless and sensorless electric motor - The invention relates to a method carried out with simple means for determining the position of the rotor in a sensorless and brushless multi-phase electric motor ( | 01-28-2010 |
| 20100295490 | MOTOR DRIVE APPARATUS AND MOTOR DRIVE METHOD - A zero-crossing detector compares a neutral node voltage of a motor with a back electromotive force of at least one of windings and outputs a first signal every time a zero-crossing is detected as a result of the comparison. A cycle detector detects a cycle of the first signal and outputs a second signal during a final portion of the cycle. A de-energizer de-energizes all the windings of the motor during at least a period of time that the second signal is being output. The zero-crossing detector performs detection of a zero-crossing during the period of time that the second signal is being output. | 11-25-2010 |
| 20110127939 | PAIR POLE ASYMMETRY COMPENSATION IN BACK ELECTROMOTIVE FORCE ZERO CROSS DETECTION - Disk drive spindle jitter is comprised of electrical noise, error due to pair pole asymmetry, and random disk speed variances. Error caused by pair pole asymmetry can be identified and compensated for by detecting over a single rotation of a rotor a plurality of zero cross signals. These signals can be statistically analyzed over a period of a plurality of revolutions of the rotor so as to identify the systematic error caused by pair poles. Once identified, this pair pole error can be used to modify zero cross signals and/or modify commutation signal driving the disk so as to arrive at a more accurate determination of disk speed and to precisely control the speed of the disk. | 06-02-2011 |
| 20110115423 | Brushless, Three Phase Motor Drive - A control method for a brushless, three-phase DC motor. A voltage induced by rotation of a rotor may be sampled at a first expected zero crossing value to produce a first sampled voltage value. An average of a plurality of sampled voltage values, including voltage values sampled at a plurality of prior expected zero crossing values and the first sampled voltage value, may be calculated. The first sampled voltage value may be subtracted from the calculated average to produce a delta zero crossing error. A pulse-width modulation duty cycle may be adjusted based on the delta zero crossing error. The pulse-width modulation duty cycle may be used to control a rotational velocity of the rotor. | 05-19-2011 |
| 20110084640 | VARIABLE PULSE WIDTH MODULATION FOR REDUCED ZERO-CROSSING GRANULARITY IN SENSORLESS BRUSHLESS DIRECT CURRENT MOTORS - Zero-crossing detection accuracy is enhanced in a sensorless brushless direct current (BLDC) motor by increasing the PWM drive frequency in anticipation of a zero-crossing event in any one or more commutation periods. Once a zero-crossing event is detected, the PWM frequency can go back to a lower normal operating frequency. Switching losses of the power drive transistors are thereby minimized while maintaining accurate zero-crossing detection for stable operation of the BLDC motor. | 04-14-2011 |
| 20110241588 | SYSTEM AND METHOD FOR CONTROLLING SENSORLESS MOTOR - A system and a method for controlling a sensorless motor are disclosed, where the system includes a motor driver and a zero crossing detector. The motor driver can drive the sensorless motor. The zero crossing detector can detect a zero-crossing point when the voltage of one motor coil of the sensorless motor is in a blanking period. | 10-06-2011 |
| 20090218974 | DRIVING BRUSHLESS DC (BLDC) MOTORS - The driving system for a tri-polar electric motor ( | 09-03-2009 |
| 20110074327 | CONTROL OF SINUSOIDALLY DRIVEN BRUSHLESS DC (BLDC) MOTORS - In response to the determination or estimation of a back EMF zero crossing event for the phase, a time T | 03-31-2011 |
| 20110062910 | Method of Driving DC Motor and Related Circuit for Avoiding Reverse Current - A motor driving method for driving a direct-current (DC) motor, designed for avoiding a reverse current induced by the Back Electromotive Force (BEMF), includes providing a driver circuit for driving the DC motor; comparing a signal level of a terminal of the DC motor and a predetermined voltage value to produce a comparing result; and controlling a specific lower gate switch to avoid the occurrence of a reverse current of the DC motor according to the comparing result. | 03-17-2011 |
| 20110084639 | SYNCHRONIZED MINIMUM FREQUENCY PULSE WIDTH MODULATION DRIVE FOR SENSORLESS BRUSHLESS DIRECT CURRENT MOTOR - Drive voltages to a sensorless brushless DC motor are regulated by varying the width of a single drive pulse (PWM pulse) centered in each of the commutation periods. Switching losses are thereby cut to an absolute minimum because there are only two transitions (on and off) in each drive commutation period. Back EMF zero-cross detectors determine the electrical timing relationships during each electrical cycle. Since the PWM drive pulses are always centered in each of the commutation periods, there will always be back EMF available for measurement of “zero-crossings.” A digital device controls power switching transistors to produce one single PWM pulse during each of the commutation periods. | 04-14-2011 |
| 20080265817 | SENSORLESS SPEED DETECTION DURING ZERO VECTOR - A speed estimation method for determining the speed of a sensorless permanent magnet brushless motor having one or more phases driven by one or more stages of an inverter, each stage including high- and low-switches connected in series across a DC Bus and having a respective common switched node, the respective switched node being coupled to a respective motor phase terminal. The method includes the steps of applying an alternating sequence of Zero Vectors to the inverter, the sequence alternating between a first Zero Vector whereby motor current does not flow in the DC Bus and a second Zero Vector wherein the high and low side switches of the inverter are alternately turned on with active vector components being injected by the inverter for each inverter stage thereby to allow motor current to flow in the DC Bus, whereby the terminals of the motor during the first and second Zero Vectors are shorted to brake the motor without substantially raising the voltage of the DC Bus during the braking time; and the speed of the motor can be determined by measuring the current in a sensor of the DC bus during the time when the second Zero Vector is applied without using a sensor in the motor. | 10-30-2008 |
| 20090026991 | SYNCHRONIZATION OF SEQUENTIAL PHASE SWITCHINGS IN DRIVING STATOR WINDINGS OF A MULTIPHASE SENSORLESS BRUSHLESS MOTOR AT SUB BEMF-DETECTABILITY SPEEDS - The method of synchronizing sequential phase switchings in driving stator windings of a multiphase sensorless brushless motor with a reconstructed information on the current angular position of a permanent magnet rotor, includes sampling on a currently non-conductive stator winding a voltage induced thereon by the resultant magnetic field produced by the drive current forced through currently conductive stator windings that inverts its sign when the rotor transitions across a plurality of significant angular positions, at which orthogonality between the resultant magnetic field and a magnetic axis of the non-excited winding verifies. The sign of the sampled voltage induced on the currently non-excited winding is compared with the sign that is expected upon transiting across the angular position of inversion by the moving rotor for the current phase drive configuration to sequentially switch to the next phase drive configuration upon verifying conformity of the sign of the sampled voltage with the expected sign. | 01-29-2009 |
| 20100039056 | ELECTRIC POWER CONVERTER - A voltage-command correction unit provided between an electric-power conversion unit and a voltage-command calculation unit provides a predetermined current range including the zero level for the detected output current, and, at a first clock time when the output current enters from outside to inside of the current range, sets a zero cross timing of the output current as a clock time for switching the polarity of the correction voltage that corrects the AC voltage command calculated and output by the voltage-command calculation unit based on the first clock time and the frequency, thereby making a configuration capable of correcting the AC voltage command with the correction voltage with the same polarity as the polarity of the output current around the zero cross point of the output current. | 02-18-2010 |
| 20100301791 | BRIDGE RECTIFIER CIRCUIT - A bridge rectifier circuit, which takes control of a current flowing through an armature winding of a motor-generator and a battery, includes rectifier elements each made of a MOSFET; phase current detection means that detect the amount and the direction of current flowing between the drain and the source of the FET; and a control means that takes on/off control of the FET by applying a control voltage between the gate and the source thereof; wherein when the phase current detection means detect a reverse current flowing through the FET exceeding a first predetermined value, the control means applies a control voltage between the gate and the source of the FET so as to turn on the FET. | 12-02-2010 |
| 20110316464 | ELECTRIC DEVICE COMPRISING AN ALTERNATING CURRENT ELECTRIC MOTOR AND A CONTROL INVERTER AND A METHOD FOR MEASURING THE ELECTROMOTIVE FORCE OF THIS DEVICE - The invention relates to an electric device ( | 12-29-2011 |
| 20120112675 | Sensorless Safety System for Determining Rotation of an Electric Household Appliance Laundry Drum Powered by a Three-Phase Asynchronous Motor - An electric household appliance ( | 05-10-2012 |
| 20100207562 | METHOD AND APPARATUS FOR DRIVING A BRUSHLESS D.C. MOTOR - A brushless D.C. motor includes having a rotor and a plurality of stator windings that define a stator field when driven by a bridge circuit, where a microprocessor drives the bridge circuit using a pulse-width modulation logic. The brushless D.C. motor is driven by triggering a commutation of the stator field; voltage induced by rotating the rotor in a non-energized stator winding is monitored to determine whether the voltage reaches, exceeds or is below a threshold voltage. A delay time between triggering the commutation of the stator field and the voltage reaching, exceeding or being below the threshold voltage is determined; and using the determined delay time a triggering time point for a next commutation of the stator field. | 08-19-2010 |
| 20120256575 | CONTROL METHOD FOR SENSORLESS MOTORS WITH ENERGY RECOVERY ABILITY - The present disclosure related to a control method for a sensorless motor with energy recovery ability, using which duty cycle of a sensorless motor can be changed by the control of complementary switches so as to enable the sensorless motor to switch between a high efficiency driving operation and an energy recovery operation while being activated. Thereby, the conduction loss and the wear and tear to the switches can be minimized while simultaneously enhancing the energy recovery efficiency and thus improving the battery life. | 10-11-2012 |
| 20120249034 | POSITION SENSING CIRCUIT FOR BRUSHLESS MOTORS - A position sensing circuit ( | 10-04-2012 |
| 20110210688 | CONTROL OF BRUSHLESS MOTOR - Systems and methods for generating a signal useful in the commutation of current through windings of brushless direct current electric motors are provided. Such methods comprises detecting a kickback pulse in a non-driven winding of a motor; detecting a rotor-induced zero crossing in the non-driven winding following the detection of the kickback pulse; and using the detection of the rotor-induced zero crossing to generate a signal useful in commutation of the motor. | 09-01-2011 |
| 20130020974 | SINGLE-PHASE BRUSHLESS MOTOR DRIVE CIRCUIT - A driving circuit for a single-phase brushless motor includes: a driving-signal-generating circuit to generate a driving signal for supplying first and second driving currents to a driving coil of the single-phase brushless motor in an alternate manner with a de-energized period therebetween; an output circuit to supply the first or the second driving current to the driving coil in response to the driving signal; and a zero-cross detecting circuit to detect a zero cross of an induced voltage, generated across the driving coil, during the de-energized period, wherein the driving-signal-generating circuit determines a length of a subsequent energized period, based on a driving cycle from a start of an energized period to a time when the zero-cross detecting circuit detects the zero cross, and the zero-cross-detecting circuit starts detection of the zero-cross after a predetermined time period has elapsed from a start of the de-energized period. | 01-24-2013 |
| 20120086376 | ELECTRIC MOTOR OPERATION APPARATUS AND METHOD - The invention relates to a method for operating an electric motor with a primary section and a secondary section, wherein the primary section has a multi-phase exciter winding comprising winding strands, each of the phase connections of said exciter winding being connected to an output connection of an end stage, wherein the end stage has controllable semi-conductor switches for applying phase voltages to the output connections, said method comprising the following steps: a) introducing an operating phase by applying the phase voltages to the output connections of the end stage such that a moving magnetic field is induced in the exciter winding, said moving field effecting a relative motion between the primary section and the secondary section, b) hinting off the phase voltage at at least one of the output connections in order to introduce a measurement phase, c) measuring the electrical back emf induced in the winding strand connected to said at least one of the output connections by virtue of the relative motion between the primary section and the secondary section in order to determine the angular difference between the phase position of the exciter current and that of the back emf, d) optionally, repeating steps a) through c). After turning off the phase voltage, the winding current in the winding strand for which the phase voltage was turned off is conducted and maintained by way of at least one free-wheeling element having a non-linear characteristic curve. A flank ( | 04-12-2012 |
| 20130009582 | SINGLE-PHASE BRUSHLESS MOTOR DRIVE CIRCUIT - A driving circuit for a single-phase-brushless motor, includes: a driving-signal-generating circuit to generate a driving signal for supplying, to a driving coil of the single-phase-brushless motor, first- and second-driving currents, alternately with a de-energized period therebetween during which neither of the first or the second driving current is supplied to the driving coil; an output circuit to supply the first or the second driving current to the driving coil in response to the driving signal; and a zero-cross detecting circuit to detect a zero cross of an induced voltage, generated across the driving coil, during the de-energized period, wherein the driving-signal-generating circuit determines a length of a subsequent energized period based on a driving cycle from a start of an energized period, during which the output circuit supplies the first or the second driving current to the driving coil, to a time when the zero-cross-detecting circuit detects the zero cross. | 01-10-2013 |
