Patent application number | Description | Published |
20130258725 | Systems and Methods for Balancing UPS Source Currents During Unbalanced Load Transient Conditions - Systems and methods for balancing current from an AC source. The method includes determining a difference between a DC voltage output by a rectifier in an uninterruptible power supply (UPS) to a DC reference voltage. The method also includes determining an error between the DC voltage and the DC reference voltage based at least in part on the difference. After determining the error, the method includes filtering a second order harmonic from the error thereby generating a filtered error. The method may then include determining one or more switching signals for one or more switching components in the rectifier based at least in part on the filtered error and sending the switching signals to the rectifier. | 10-03-2013 |
20140036555 | Intelligent Level Transition Systems and Methods for Transformerless Uninterruptible Power Supply - Systems and methods are provided for controlling an uninterruptible power supply (UPS) to transition between three- or higher-level operation and two-level operation in a neutral-point-clamped (NPC) inverter. In an example, a UPS system includes an NPC inverter and a controller. The NPC inverter may supply power to a load. The controller may control the inverter to operate in a three-level mode or higher when the load is substantially balanced and to operate in a two-level mode when the load is substantially unbalanced. | 02-06-2014 |
20140368043 | SYSTEMS AND METHODS FOR GRID INTERACTIVE UPS - A grid interactive uninterruptible power supply (UPS) is provided. The grid interactive UPS includes a first path including a rectifier, an inverter coupled in series with the rectifier, and a battery coupled in parallel with the inverter. The grid interactive UPS further includes a second path in parallel with the first path, wherein the grid interactive UPS is operable to supply power from the battery to a grid coupled to an input of the grid interactive UPS. | 12-18-2014 |