| Patent application number | Description | Published |
|---|
| 20090251009 | Drive Isolation Transformer Controller and Method - A transformer controller for a drive isolation transformer is provided. The transformer may include multiple sets of primary windings as an input, and the transformer controller may include multiple branches coupled between a power source and the transformer. Each branch may be coupled to its own primary winding on the transformer, and may include one or more components, such as an isolation switch, a fuse, contactor, or circuit breaker. One or more of the branches may include a pre-charge reactor to limit inrush or capacitor charging current occurring during startup, and may include a pre-charge contactor to remove the pre-charge reactor from the circuit when the startup process has reached a certain level (e.g., the charging or inrush current has dissipated, or a DC bus reaches a charged state). | 10-08-2009 |
| 20090251935 | Multi-Pulse Rectifier for AC Drive Systems having Separate DC Bus Per Output Phase and Multiple Isolation Transformers - An 18n-pulse rectifier for AC drive systems having a separate DC bus for each output phase is provided, where n=any positive integer. The rectifier uses three separate phase rectifiers, one for each output phase of a transformer, each comprised of 2n six-pulse diode bridges connected in series or parallel. Each phase rectifier may be supplied with n unique sets of phase inputs from a transformer secondary winding. In some configurations, the n sets of inputs provided to each rectifier are separated by 60/n degrees of phase (when n is greater than 1), while the corresponding inputs to neighboring rectifiers are separated by 20/n degrees of phase. In a 36-pulse example, the phase offsets for the inputs provided to the rectifiers may be −25° and +5° from the transformer primary winding (for the first rectifier), −15° and +15° from the primary winding (for the second rectifier) and −5° and +25° from the primary winding (for the third rectifier). Each set of inputs may include three lines of in-phase current, and may be coupled to one of the six-pulse diode bridges. In some configurations, two identically-wound transformers may be used to supply output voltages to the rectifiers. The transformers may each supply the same phase offsets to each rectifier, in accordance with the methodology above, which may support higher-capacity applications. | 10-08-2009 |
| 20100271045 | Open Fuse Detection by Neutral Point Shift - Systems and methods are shown for detecting a blown fuse in a three-phase line by comparing neutral points in the line before and after the fuses. Diode rectifier circuits may be used to compare the neutral points and generate a DC output voltage when neutral points are off from one another, and photocoupler circuits may provide electrical isolation when signaling a neutral point shift. The neutral points compared need not be on immediate sides of the fuses, so intermediate components may exist, and in some embodiments one of the compared points may be within a load connected to the three-phase line. | 10-28-2010 |
