An electric power supply system includes an alternating current electric power supply circuit that converts direct current electric power of a first direct current sweep unit including a battery string into alternating current electric power using a first inverter and outputs it, and an alternating current sweep unit that includes a U-phase battery string, a V-phase battery string, and a W-phase battery string that are Y-connected. Output densities of batteries of the battery string are higher than output densities of batteries of the alternating current sweep unit. Alternating current electric power is output from the alternating current sweep unit and the alternating current electric power supply circuit, and after a predetermined period elapses, the output of the alternating current electric power from the alternating current electric power supply circuit is stopped.

An electric power supply system includes an alternating current electric power supply circuit that converts direct current electric power of a first direct current sweep unit including a battery string into alternating current electric power using a first inverter and outputs it, and an alternating current sweep unit that includes a U-phase battery string, a V-phase battery string, and a W-phase battery string that are Y-connected. Output densities of batteries of the battery string are higher than output densities of batteries of the alternating current sweep unit. Alternating current electric power is output from the alternating current sweep unit and the alternating current electric power supply circuit, and after a predetermined period elapses, the output of the alternating current electric power from the alternating current electric power supply circuit is stopped.

A DC to AC converter includes an input configured to receive a DC input voltage, an output and two serially connected capacitors connected across the output. The two serially connected capacitors including a first capacitor and a second capacitor connected together at a connection node. The converter also includes a first parallel converter connected between the input and the connection node and a second parallel converter connected between the input and the connection and in parallel with the first parallel converter. The converter also includes a controller that selectively connects the first and second parallel converters to the input based on a first duty cycle (D1) and second duty cycle (D2), respectively. The controller determines D1 based on comparing a desired alternating current signal across the second first to a measured alternating current signal across the first capacitor such that D1 varies over time.

A power module includes a insulation substrate, a first and a second input terminal supported by the insulation substrate, a plurality of arm circuits provided on the insulation substrate, and a plurality of output terminals corresponding to the plurality of arm circuits. The arm circuits each include a part of a wiring pattern formed on the insulation substrate, and a first switching element and a second switching element mutually connected in series via the part of the wiring pattern. The output terminals are each connected to a connection point between the first switching element and the second switching element in a corresponding one of the plurality of arm circuits. The plurality of arm circuits are located so as to overlap with a circle surrounding the first input terminal, as viewed in a thickness direction the insulation substrate.

A power module includes a insulation substrate, a first and a second input terminal supported by the insulation substrate, a plurality of arm circuits provided on the insulation substrate, and a plurality of output terminals corresponding to the plurality of arm circuits. The arm circuits each include a part of a wiring pattern formed on the insulation substrate, and a first switching element and a second switching element mutually connected in series via the part of the wiring pattern. The output terminals are each connected to a connection point between the first switching element and the second switching element in a corresponding one of the plurality of arm circuits. The plurality of arm circuits are located so as to overlap with a circle surrounding the first input terminal, as viewed in a thickness direction the insulation substrate.

A method for operating a power converter as an inverter between a DC voltage and an AC voltage grid is disclosed. For each AC voltage phase of the AC voltage grid, the power converter has at least one half-bridge which is connected to the AC voltage phase and has two semiconductor switches. Each semiconductor switch is reversed-connected in parallel with a diode. An activation angle range is determined for each semiconductor switch within an angle period, the lower range limit of which activation angle range is formed by subtracting a pre-firing angle from the lower range limit of a switch angle range, and the upper range limit of which activation angle range is formed by subtracting a pre-extinction angle from the upper range limit of the switch angle range.

A utility-scale energy storage and conversion system can operate two or more inverter groups such that their reactive power commands are proportional to their available reactive power range. The control system can therefore distribute the reactive power commands in proportion to the available Q range, thereby ensuring that all inverters in the utility-scale energy storage and conversion system 100 operate with the same Q “headroom”. In addition, the utility-scale energy storage and conversion system can use an on-load tap changer (LTC) to adjust a terminal voltage associated with a first group of inverters and a second group of inverters. The first group of inverters can be associated with a first rating and the second group of inverters can be associated with a second rating that is greater than the first rating.

A utility-scale energy storage and conversion system can operate two or more inverter groups such that their reactive power commands are proportional to their available reactive power range. The control system can therefore distribute the reactive power commands in proportion to the available Q range, thereby ensuring that all inverters in the utility-scale energy storage and conversion system 100 operate with the same Q “headroom”. In addition, the utility-scale energy storage and conversion system can use an on-load tap changer (LTC) to adjust a terminal voltage associated with a first group of inverters and a second group of inverters. The first group of inverters can be associated with a first rating and the second group of inverters can be associated with a second rating that is greater than the first rating.

Disclosed is a sensor circuit including a resistance for detection connected to a wire, a first terminal pair comprised of terminal wires connected respectively to terminals of the resistance for detection, a second terminal pair comprised of terminal wires short-circuited to each other at one terminal of the resistance for detection, and a sensing section to measure a current or voltage from which a noise component is removed using a detection signal inputted thereto via the first terminal pair and a detection signal inputted thereto via the second terminal pair.

Disclosed is a sensor circuit including a resistance for detection connected to a wire, a first terminal pair comprised of terminal wires connected respectively to terminals of the resistance for detection, a second terminal pair comprised of terminal wires short-circuited to each other at one terminal of the resistance for detection, and a sensing section to measure a current or voltage from which a noise component is removed using a detection signal inputted thereto via the first terminal pair and a detection signal inputted thereto via the second terminal pair.