Abstract: A system for load balancing on a multi-phase power line connected to a single phase lateral power line, includes a contactor configured to selectively connect each phase of the multi-phase power line to the single phase lateral power line. There is a phase change device connected in parallel with the contactor and a controller. During the phase change state, the controller connects the input of the phase change device to the multi-phase power line and connects the output of the phase change device the single phase lateral power line. The controller causes the phase change device to output a voltage to the single phase lateral line initially aligned with the first phase and then rotated to align with the second phase and causes the contactor changes connection to the second phase of the multi-phase power line and disconnect the phase change device from the power lines.

Abstract: A system for load balancing on a multi-phase power line connected to a single phase lateral power line, includes a contactor configured to selectively connect each phase of the multi-phase power line to the single phase lateral power line. There is a phase change device connected in parallel with the contactor and a controller. During the phase change state, the controller connects the input of the phase change device to the multi-phase power line and connects the output of the phase change device the single phase lateral power line. The controller causes the phase change device to output a voltage to the single phase lateral line initially aligned with the first phase and then rotated to align with the second phase and causes the contactor changes connection to the second phase of the multi-phase power line and disconnect the phase change device from the power lines.

Abstract: A static synchronous compensator configured to be installed in and provide reactive power to a medium voltage electric distribution system. There is a multi-level cascaded H-bridge (CHB) converter in an enclosure, having a nominal operating voltage in the medium voltage range. There is a first electrical bushing connecting the medium voltage electric distribution system to the input of the CHB converter. There is a second electrical bushing connecting ground or floating ground to the output of the CHB converter. There is a cooling system, which circulates the cooling fluid between in the interior of the enclosure to cool the CHB converter. There is a controller to control the converter to output reactive power at a medium voltage level.

Abstract: A static synchronous compensator configured to be installed in and provide reactive power to a medium voltage electric distribution system. There is a multi-level cascaded H-bridge (CHB) converter in an enclosure, having a nominal operating voltage in the medium voltage range. There is a first electrical bushing connecting the medium voltage electric distribution system to the input of the CHB converter. There is a second electrical bushing connecting ground or floating ground to the output of the CHB converter. There is a cooling system, which circulates the cooling fluid between in the interior of the enclosure to cool the CHB converter. There is a controller to control the converter to output reactive power at a medium voltage level.

Abstract: A static synchronous compensator includes at least one converter pole for producing a first phase of an AC voltage waveform having a fundamental cycle. The first phase of the AC voltage waveform includes alternating converter pole charging and discharging regions in each fundamental cycle. The at least one converter pole includes a plurality of cascaded H-bridge cells, each having a DC voltage source and a plurality of switches. The switches are capable of being switched to produce a plurality of switching states. There is a controller configured to control the switching states of the plurality of switches of each of the cascaded H-bridge cells based on the voltages of DC voltage sources of the H-bridge cells and on whether the AC waveform is in the converter pole charging region or the converter pole discharging region.

Abstract: A static synchronous compensator includes at least one converter pole for producing a first phase of an AC voltage waveform having a fundamental cycle. The first phase of the AC voltage waveform includes alternating converter pole charging and discharging regions in each fundamental cycle. The at least one converter pole includes a plurality of cascaded H-bridge cells, each having a DC voltage source and a plurality of switches. The switches are capable of being switched to produce a plurality of switching states. There is a controller configured to control the switching states of the plurality of switches of each of the cascaded H-bridge cells based on the voltages of DC voltage sources of the H-bridge cells and on whether the AC waveform is in the converter pole charging region or the converter pole discharging region.

Abstract: A method for providing electric power to a power system includes receiving, at a slave node of a power converter having a plurality of slave nodes, a first synchronization signal via a first communication channel, the first synchronization signal purporting to represent a master timing characteristic of a master control node of the converter; receiving, at the slave node of the converter, a second synchronization signal via a second communication channel, the second synchronization signal purporting to represent a master timing characteristic of the master control node of the converter; synchronizing an internal timing characteristic of the slave control node with the master timing characteristic of the master control node using the first synchronization signal; determining that the first synchronization signal is invalid; and synchronizing an internal timing characteristic of the slave control node with the master timing characteristic of the master control node using the second synchronization signal.

Abstract: A method for providing electric power to a power system includes receiving, at a slave node of a power converter having a plurality of slave nodes, a first synchronization signal via a first communication channel, the first synchronization signal purporting to represent a master timing characteristic of a master control node of the converter; receiving, at the slave node of the converter, a second synchronization signal via a second communication channel, the second synchronization signal purporting to represent a master timing characteristic of the master control node of the converter; synchronizing an internal timing characteristic of the slave control node with the master timing characteristic of the master control node using the first synchronization signal; determining that the first synchronization signal is invalid; and synchronizing an internal timing characteristic of the slave control node with the master timing characteristic of the master control node using the second synchronization signal.

Abstract: A wind turbine 36 has a back-to-back AC/DC/AC power electronic converter chain in which the grid side converter 48 is connected in series with DFIG stator windings 64. The machine side converter 56 is fed from the rotor windings 54 of the DFIG 44. Series connection of the grid side converter 48 enables voltage sag ride-through capability via control of the stator flux. In the event of a grid voltage sag, the series converter allows for a controlled response in the stator flux and electromagnetic shaft torque, protects the machine side converter and enables continued power delivery to the grid.

Abstract: A wind turbine 36 has a back-to-back AC/DC/AC power electronic converter chain in which the grid side converter 48 is connected in series with DFIG stator windings 64. The machine side converter 56 is fed from the rotor windings 54 of the DFIG 44. Series connection of the grid side converter 48 enables voltage sag ride-through capability via control of the stator flux. In the event of a grid voltage sag, the series converter allows for a controlled response in the stator flux and electromagnetic shaft torque, protects the machine side converter and enables continued power delivery to the grid.