Toshiba Mitsubishi-electric Industrial Systems Corporation

Tmeic Corporation

Yoshihiro Tawada

Tomoya Katsukura

Masahiro Kinoshita

Issei Fukasawa

Daiki Terashima

Tatsuaki Ambo

Kenta Yamabe

Ruben Alexis Inzunza Figueroa

Tsuguhiro Tanaka

Mohammad Bani Shamseh

Kazuki Aoyagi

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 apparatus includes a power conversion circuit configured to convert DC power into three-phase AC power; and a control device configured to generate a two-phase negative-phase current from a three-phase AC current output from the power conversion circuit, and to detect an open phase on an output side of the power conversion circuit based on a magnitude of an amplitude of the two-phase negative-phase current. The control device may be configured to determine an occurrence of the open phase when the magnitude of the amplitude of the two-phase negative-phase current increases, and an electric current of at least one phase of the three-phase AC current decreases.

Open-phase detection circuit and power conversion apparatus

A power conversion device include a switch for switching so as to output by selecting one of a command value the first DC voltage controller outputs or holds or the command value the second DC voltage controller outputs, a detector that detects the opening of the contactor and the recovery from voltage disturbance in the system on the AC side of the power conversion circuit, and a switching controller controls the switching of the switch so that selects and outputs the command value output by the second DC voltage controller when the detector detects the opening of the contactor, and selects and outputs the command value held by the first DC voltage controller when the detector detects the recovery from the voltage disturbance.

Power conversion device converting DC power supply into AC power

A power conversion device including a power conversion circuit, an AC filter circuit, and a calculation unit. The power conversion circuit converts DC input power from a DC power supply to output a first AC output current and a first AC output voltage. The AC filter circuit filters the first AC output current and the first AC output voltage to generate a second AC output current and a second AC output voltage. The calculation unit calculates an estimated value of an upper impedance based on a difference value between a first voltage value and a second voltage value, the first voltage value being a value of the second AC output voltage at a time of stop of the power conversion circuit or at a time of zero output from the power conversion circuit or at a time of a certain amount of output from the power conversion circuit.

Power conversion device that calculates an estimated value of an upper impedance

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

A power conversion device includes: a power conversion circuit connected to a direct-current power supply and a power system and configured to perform conversion between direct-current power and alternating-current power; a phase-locked loop circuit configured to output a phase instruction value based on a system alternating-current voltage phase of the power system; and a control circuit configured to control the power conversion circuit based on the phase instruction value from the phase-locked loop circuit. The phase-locked loop circuit includes: a phase difference calculation section configured to calculate a phase difference in a predetermined cycle, the phase difference representing a deviation of the phase instruction value from the system alternating-current voltage phase of the power system; a phase difference correction section; and a phase instruction value generation section configured to output the phase instruction value based on an output of the phase difference correction section.

Power conversion device

A testing device of an inverter device includes a power supply device including an AC-DC conversion circuit for converting AC power received from an AC power supply into DC power and a control part for controlling the AC-DC conversion circuit and a filter circuit interposed between a tested inverter device to be tested and the power supply device, having a reactor and a capacitor, and delivering the DC power output from the power supply device to the tested inverter device. The control part is configured to execute output adjustment of the AC-DC conversion circuit when a test start signal is generated to start an instantaneous voltage abnormality test which is a test changing magnitude of power supply voltage of the AC power supply in a predetermined direction being either one of increase or decrease during operation of the tested inverter device and the power supply device.

Testing device of inverter device

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

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 control device for an electric power conversion apparatus, the control device detecting occurrence of an earth fault in a direct-current path in a system in which the direct-current path between a solar cell module and an electric power conversion apparatus is grounded, is provided. The control device for the electric power conversion apparatus includes: a grounding control unit configured to, in a system in which a direct-current path between a solar cell module and an electric power conversion apparatus is grounded via a switch, control a switch; and an earth fault determination unit configured to, when the switch is open under the controlled of the grounding control unit, detect whether or not an earth fault has occurred in the direct-current path.

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Tokyo, Japan

Yoshihiro Tawada