Toshiba Mitsubishi-electric Industrial Systems Corporation

Tsuguhiro Tanaka

Masahiro Kinoshita

Tatsuaki Ambo

Naoki Fujiwara

Paul S Bixel

Yoshihiro Tawada

Yuji Matsuoka

Katsuya Umeda

A power conversion device includes: a power conversion circuit for converting DC power into AC power; and a controller to generate a control signal for the power conversion circuit based on a control command value and an output voltage of the power conversion circuit. The controller is configured to generate the control signal based on a corrected voltage command value calculated by subtraction correction to decrease a voltage command value when the output voltage of the power conversion circuit is equal to or higher than a predetermined threshold value, and to generate the control signal based on a voltage command value not subjected to the subtraction correction when the output voltage of the power conversion circuit is lower than the threshold value.

Power conversion device and power conversion system

A power system includes an AC power supply, an AC filter circuit, an AC circuit breaker, and a first switch. The AC filter circuit includes an inductor having one end connected in series to an output end of the AC power supply, and a capacitor having one end receiving a voltage at another end of the inductor. The AC circuit breaker exists between the other end of the inductor and an electric power grid. The first switch switches a state between the one end of the capacitor and a wire connecting the other end of the inductor to the AC circuit breaker, between a connected state and a disconnected state. The AC power supply may be a generator and include a generator control unit controlling the generator. The generator control unit may turn off the first switch when the AC power supply operates in a predetermined standby mode.

Power conversion device, power system and method of suppressing reactive power in power system

According to an embodiment of the invention, a power conversion device that includes a power converter, a direct current capacitor, a voltage sensor, a rectifying element, an electromagnetic contactor, and a control circuit is provided. The power converter includes a pair of direct current terminals connected to a direct current power supply, includes multiple alternating current terminals connected to an electric power system of alternating current, converts direct current power input from the direct current power supply into alternating current power, and supplies the alternating current power to the electric power system. The direct current capacitor is connected between the pair of direct current terminals. The voltage sensor detects a voltage value of the direct current capacitor. The rectifying element is provided between the direct current capacitor and the direct current power supply and suppresses a reverse flow of electrical power from the power converter and the direct current capacitor into the direct current power supply. The electromagnetic contactor is connected in parallel with the rectifying element. The control circuit controls operations of the power converter and the electromagnetic contactor. In the case where the voltage value of the direct current capacitor detected by the voltage sensor is a prescribed value or more, the control circuit engages the electromagnetic contactor and supplies active power from the power converter to the electric power system; and in the case where the voltage value of the direct current capacitor detected by the voltage sensor is less than the prescribed value, the control circuit opens the electromagnetic contactor and supplies a reactive power from the power converter to the electric power system.

Power conversion device and method for operating same with reactive power compensation

An inverter controller is configured to control inverters connected in parallel. The inverter controller is configured to closes switch of a first inverter and turn on a first switching element provided at the first inverter to charge capacitors of the inverters at the time of starting the inverters, and to close the other switches after the capacitors are charged.

Devices and methods for controlling current in inverters

A power converter includes inverters, AC sides of the inverters being connected in parallel, and a controller configured to control total output power of the inverters by controlling output power of at least one of the inverters in a control cycle shorter than a shortest communication cycle which allows communication with each of the inverters.

Growing community of inventors

Tokyo, Japan

Tsuguhiro Tanaka