A power conversion system comprising, three full wave LLC resonant converters each of which has an associated high frequency isolation transformer, a full wave rectifier and an unfolding inverter, to provide a direct connection to a Medium Voltage (MV) three-phase grid for a high power photovoltaic system.

An electric power conversion circuit includes: first through fourth port terminals; first through fourth switches that are connected with each other in a bridge configuration; fifth through eighth switches that are respectively connected in parallel with the first through fourth switches; first through eighth diodes that are respectively connected in series with the first through eighth switches; a first bootstrap circuit that is connected to control terminals of the first, second, fourth, and sixth switches; and a second bootstrap circuit that is connected to control terminals of the third, fifth, seventh, and eighth switches.

An electric power conversion circuit includes: first through fourth port terminals; first through fourth switches that are connected with each other in a bridge configuration; fifth through eighth switches that are respectively connected in parallel with the first through fourth switches; first through eighth diodes that are respectively connected in series with the first through eighth switches; a first bootstrap circuit that is connected to control terminals of the first, second, fourth, and sixth switches; and a second bootstrap circuit that is connected to control terminals of the third, fifth, seventh, and eighth switches.

According to an embodiment, a power converter (1) includes a main circuit (10), an electrification control unit (25), and an analysis unit (24). The main circuit includes a plurality of switching devices (Q1 to Q4), converts direct-current power into multiphase alternating-current power through switching of the plurality of switching devices, is able to supply the multiphase alternating-current power to an alternating-current load (2) connected to an output side, and output a detection result of a device short circuit current flowing in each of the plurality of switching devices. The electrification control unit electrifies the plurality of switching devices for a predetermined time based on one of a plurality of pre-decided analysis test electrification patterns. The analysis unit analyzes soundness of the main circuit using a load current flowing from the main circuit to the alternating-current load, a phase voltage output by the main circuit, and data at the time of electrification for the predetermined time with regard to the device short circuit current flowing in each of the plurality of switching devices.

According to an embodiment, a power converter (1) includes a main circuit (10), an electrification control unit (25), and an analysis unit (24). The main circuit includes a plurality of switching devices (Q1 to Q4), converts direct-current power into multiphase alternating-current power through switching of the plurality of switching devices, is able to supply the multiphase alternating-current power to an alternating-current load (2) connected to an output side, and output a detection result of a device short circuit current flowing in each of the plurality of switching devices. The electrification control unit electrifies the plurality of switching devices for a predetermined time based on one of a plurality of pre-decided analysis test electrification patterns. The analysis unit analyzes soundness of the main circuit using a load current flowing from the main circuit to the alternating-current load, a phase voltage output by the main circuit, and data at the time of electrification for the predetermined time with regard to the device short circuit current flowing in each of the plurality of switching devices.

The grid-connected inverter system according to one embodiment of the present invention may convert direct current supplied from a direct current source into alternating current, receive a control command from an upper level controller and a power electronics building block group comprising a plurality of power electronics building blocks for supplying the converted alternating current to a grid, determine the number of power electronics building blocks which will operate according to the control command, and transmit a control signal for operating the determined number of power electronics building blocks to corresponding power electronics building blocks.

The grid-connected inverter system according to one embodiment of the present invention may convert direct current supplied from a direct current source into alternating current, receive a control command from an upper level controller and a power electronics building block group comprising a plurality of power electronics building blocks for supplying the converted alternating current to a grid, determine the number of power electronics building blocks which will operate according to the control command, and transmit a control signal for operating the determined number of power electronics building blocks to corresponding power electronics building blocks.

A resonance oscillator circuit is provided to include first and second oscillators. The first oscillator includes a first LC resonator circuit and an amplifier element, and oscillates by shifting a phase of an output voltage with a predetermined phase difference and feeding the output voltage back to the amplifier element. The second oscillator oscillates by generating a gate signal, which has a frequency identical to that of the output voltage, and drives the amplifier element, by shifting the phase of the output voltage with the phase difference and feeding the gate signal back to an input terminal of the amplifier element, by using the amplifier element as a switching element and using the first oscillator as a feedback circuit. The phase difference is a value substantially independent of an inductance of the first LC resonator circuit and a load, to which the output voltage is applied.

A method for controlling an inverter configured to power electrically a motor including a stator and a rotor capable of being rotated relative to the stator when the motor is electrically powered, the inverter including a plurality of switches suitable for being controlled to open/close in order to regulate the power supply of the motor, each switch having a predetermined transition time from a closed state to an open state, and a predetermined transition time from the open state to the closed state, wherein the method includes the step of not generating the command to open and close the switches when this violates the predetermined transition times from a closed state to an open state, and the predetermined transition times from the open state to the closed state.

This semiconductor module is provided with a first conductive plate, a first switching element mounted on the first conductive plate, a second conductive plate provided on the first switching element, a second switching element laminated on the second conductive plate, a third conductive plate provided on the second switching element, and first and second control terminals. Each of the switching elements is configured using silicon carbide. On a second lower conductive plate surface of the second conductive plate, a protruding part is provided that protrudes from said second lower conductive plate surface toward a first element upper surface and that is bonded to a first upper electrode.