Tmeic Corporation

Toshiba Mitsubishi-electric Industrial Systems Corporation

Tomoya Katsukura

Yoshihiro Tawada

Issei Fukasawa

Daiki Terashima

Masahiro Kinoshita

Yasuaki Mitsugi

Tatsuhito Nakajima

Kenta Yamabe

Tomonori Ujiie

Takumi Narita

A control apparatus is a control apparatus for a power conversion apparatus including at least one AC capacitor disposed on the output side of an inverter and disconnected from a circuit when the AC capacitor malfunctions and including a current component extractor that acquires current values of the current flowing through the AC capacitor during synchronization control that synchronizes the output voltage from the inverter with a system voltage of a system, the synchronization control performed during activation of the power conversion apparatus with an AC switch on the side facing the system open, and extracts the value of a current component having a frequency synchronized with the frequency of the output voltage from the inverter out of the current values.

Control apparatus, electric power conversion apparatus, and method for detecting failure of AC capacitor

A control device includes a modulation rate calculator configured to calculate a modulation rate based on a DC voltage on a DC side an, a limiter configured to update a DC voltage command lower bound limiter based on the lower bound limiter operation value; a maximum power point tracking controller configured to calculate a first DC voltage command value and determine a second DC voltage command value based on the calculated first DC voltage command value and the DC voltage command lower bound limiter set to the limiter, and an inverter controller configured to control an inverter of the power conversion system based on the second DC voltage command value.

Control device and power conversion system

A control device is a control device of a power conversion device, and includes a conversion value calculation unit that acquires a current value of a current flowing in an alternating-current capacitor connected to a capacitor circuit in an output circuit on an alternating-current side of an inverter circuit and performs conversion of the current value to obtain a predetermined conversion value, and a failure detection unit that compares the conversion value obtained by the conversion value calculation unit and a predetermined determination value to be used in failure detection to detect a failure of the alternating-current capacitor.

Control device and power conversion device

A protection system including: a DC power supply; a power converter that converts DC power of the DC power supply into AC power, a circuit breaker that is series-connected to an electrical path located between the DC power supply and the power converter and can open the electrical path; a DC capacitor connected to a circuit located in the power converter; a timer that counts a lapse of a predetermined length of time from turn-on of the circuit breaker; a current detector that detects current flowing in the power converter; and a protection determiner that issues an open operation command to the circuit breaker when the current detector does not detect a decrease in the current after the timer has counted a lapse of the predetermined length of time from turn-on of the circuit breaker.

Protection system, photovoltaic system, and protection method

A power conversion device is provided, and includes a major circuit part, and a control device; the major circuit part includes a power conversion part converting, into AC power, power that is input, and a filter circuit causing the AC power output from the power conversion part to approach a sine wave; the control device controls power conversion by the major circuit part by controlling an operation of the power conversion part; the control device includes an overcurrent suppression controller; the overcurrent suppression controller calculates instantaneous value voltage output command values of the phases of the AC power output from the power conversion part to suppress an overcurrent at the output end of the major circuit part. Accordingly, a power conversion device and a control device of the power conversion device are provided in which the generation of an overcurrent can be suppressed even when a voltage-controlled operation is performed.

Power conversion device and control device having overcurrent suppression

A power conversion device is provided, and includes a major circuit part and a control device; the major circuit part includes a power conversion part converting, into AC power, power that is input, and a filter circuit causing the AC power output from the power conversion part to approach a sine wave; the control device controls power conversion by the major circuit part by controlling an operation of the power conversion part; the control device includes an overcurrent suppression controller; the overcurrent suppression controller calculates instantaneous value voltage output command values of the phases of the AC power output from the power conversion part to suppress an overcurrent at the output end of the major circuit part. Accordingly, a power conversion device and a control device of the power conversion device are provided in which the generation of an overcurrent can be suppressed even when a voltage-controlled operation is performed.

Power conversion device and control device

A controller of a power conversion device including a power converter connected between a direct current (DC) power supply and an alternating current (AC) power supply, includes: a damping control term calculation unit configured to calculate a value of pulsation of a DC voltage applied between the DC power supply and the power converter, or pulsation of a DC current flowing between the DC power supply and the power converter; and a current control unit configured to output, to the power converter, a command value for adjusting the power of the power converter so that a pulsation component corresponding to the pulsation value calculated by the damping control term calculation unit is reduced in accordance with a command value based on the value calculated by the damping control term calculation unit. The power conversion device can reduce resonance without including a damping resistor.

Controller of power conversion device

A power converter includes a power conversion circuit including a direct-current terminal connected to a solar cell panel, and an alternating-current terminal connected to an alternating-current power system, the power conversion circuit being configured to convert direct-current power generated by the solar cell panel into alternating-current power and to supply the alternating-current power to the alternating-current power system; a current detection unit configured to detect a direct current flowing between the solar cell panel and the power converter; and a control circuit including a power generation mode in which the control circuit controls the power conversion circuit to output active power generated from the direct-current power generated by the solar cell panel to the alternating-current power system, and a reactive power compensation mode in which the control circuit controls the power conversion circuit to output reactive power to the alternating-current power system.

Power converter

An open phase detection system for a power conversion system includes a phase difference abnormality detection unit, an amplitude difference abnormality detection unit, and an open phase determination unit. The phase difference abnormality detection unit outputs a phase difference abnormality signal when an absolute value of a phase difference between a current flowing through a reactor and a current flowing through a capacitor is equal to or smaller than a phase threshold value. The amplitude difference abnormality detection unit outputs an amplitude difference abnormality signal when an absolute value of a value based on an amplitude difference between the current flowing through the reactor and the current flowing through the capacitor is equal to or smaller than an amplitude threshold value. The open phase determination unit outputs an open phase signal when receiving inputs of both the phase difference abnormality signal and amplitude difference abnormality signal.

Open phase detection system for power conversion system

A power conditioner includes an inverter circuit that converts a DC voltage into an AC voltage, a voltage dividing circuit having one end connected to the positive electrode input terminal and the other end connected to the negative electrode input terminal, and a ground fault detector configured to receive a voltage divided by the voltage dividing circuit as an input voltage signal and to detect an occurrence of a ground fault based on the magnitude of the voltage of the input voltage signal. the ground fault detector emits an AC ground fault detection signal when the input voltage signal includes a first voltage signal having a frequency equal to or higher than a predetermined first frequency and a deviation of the first voltage signal with respect to an AC ground reference potential is equal to or larger than an AC ground fault detection voltage.

Growing community of inventors

Tokyo, Japan

Tomoya Katsukura