Toshiba Mitsubishi-electric Industrial Systems Corporation

Kabushiki Kaisha Toshiba

Toshiba International Corporation

Tokyo Shibaura Denki Kabushiki Kaisha

Tatsuaki Ambo

Yuji Matsuoka

Ruben Alexis Inzunza Figueroa

Chihiro Okado

Masahiro Kinoshita

Paul S Bixel

Yoshihiro Tawada

Tsuguhiro Tanaka

Yoshihito Nomura

Chieko Umeno

Naoki Fujiwara

Issei Fukasawa

Eiichi Ikawa

David Westmoreland

Takeshi Sumiya

Katsumi Maekawa

Saburou Souma

Saburo Souma

Kazushi Ichimura

Gary Dean Conner

Ryuta Saka

A distributed-power-supply power conversion system includes a plurality of power inverters configured to invert DC power to AC power; and a control device configured to select at least one power inverter from the plurality of power inverters as a power inverter used for testing, and configured to perform an energization test of the power inverter used for testing in a state where an AC side of the power inverter used for testing is disconnected from a system, and is connected to an AC power supply device and to a load bank, and a voltage on the AC side of the power inverter used for testing is established. The distributed-power-supply power conversion system can perform an energization test of a power inverter before a system receives power.

Distributed-power-supply power conversion system

A power conversion system includes plural power conversion apparatuses and a server connected to each of the plural power conversion apparatuses. Each of the plural power conversion apparatuses includes a power conversion circuit interconnected with a power system, a calculating unit configured to calculate, based on an output current and an output voltage of the power conversion circuit, at least one information of reactive power and a reactive current output by the power conversion circuit, a storing unit configured to accumulate, in a storage device, time-series reactive power information which is information associating time and the at least one information calculated by the calculating unit, and a communication interface configured to transmit the time-series reactive power information stored in the storage device to the server. The server is constructed to collect the time-series reactive power information of each of the plural power conversion apparatuses via the communication interface.

Power conversion apparatus and power conversion system

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 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.

Control device for electric power conversion apparatus

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

A photovoltaic system includes photovoltaic cells, inverters, a reduced electricity output state determiner which determines whether each of the photovoltaic cells is in a reduced electricity output state, a first command value generator which generates a first command value for decreasing a first power factor of a first inverter determined as in the reduced electricity output state, a second command value generator which generates a second command value for increasing a second power factor of at least one of second inverters so as to compensate for output power of the first inverter, and a controller which controls the inverters.

Photovoltaic system

A control device () of an inverter converts electrical power generated by a solar cell () into alternating current power connecting to an electric power system (). The control device includes: an alternating current voltage sensor () sensing a system voltage (Vr) of the electric power system; an MPPT executer () controlling a direct current voltage (Vdc) applied to the inverter () to cause the electrical power output from the solar cell () to be a maximum when the direct current voltage (Vdc) is higher than a lower limit (VL); a direct current voltage lower limit calculatorreducing the lower limit (VL) when the system voltage (Vr) is lower than a predetermined voltage; and an electrical power controller () controlling reactive power based on the system voltage (Vr), the reactive power being output from the inverter ().

Control device of inverter

There is provided an inverter control apparatus, a capacitor being provided on an AC side of the inverter. The apparatus includes a system voltage detector detects a system voltage, a differentiation unit calculates a differential value of the system voltage, a correction current instruction value calculator calculates a correction current instruction value for correcting a current instruction value set for an output current of the inverter, based on the differential value of the system voltage, a current instruction value correction unit corrects the current instruction value, based on the correction current instruction value, and a controller controls the inverter based on the current instruction value.

Inverter control apparatus

There is provided a fault detecting apparatus for detecting a fault in an electric circuit including connecting circuits and an aggregating circuit. The fault detecting apparatus includes a fault detector that detects a fault when at least one of connecting circuit current detectors detects that a current flows and an aggregating current detector detects that a current does not flow.

Fault detecting apparatus and detecting method of the same

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 conversion device includes a smoothing capacitor, an input voltage detection unit, a power conversion unit, and a controller. The input voltage detection unit detects a voltage value of the input voltage. The power conversion unit converts a direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage to output the alternating-current voltage to a power system. The controller has a first operation mode of outputting active power to the power system, has a second operation mode of outputting reactive power to the power system, determines whether or not the voltage value is one of equal to and higher than a determination value, and makes a transition from the first operation mode to the second operation mode within a predetermined time from a time point when it is determined that the voltage value is lower than the determination value.

Power conversion device and method of controlling the same

There is provided a control apparatus for a photovoltaic inverter. The control apparatus includes a system voltage detector, a DC voltage detector that detects a DC voltage applied to the inverter, an output voltage deficiency detector that detects an output voltage deficiency of the inverter based on the system voltage and the DC voltage, an output-current detector, an output-current distortion detector that detects distortion of the output current based on a harmonic included in the output current, a MPPT controller, and an output-current distortion controller that performs control to set the DC voltage applied to the inverter to a voltage at a power point less than a maximum power point when the output voltage deficiency is detected and the distortion of the output current is detected.

Control apparatus for photovoltaic inverter

According to some preferred embodiments, power converter includes a comparator circuit with feedback from current-fed PI or PID control to select one of two regeneration times of at least one active clamp: i) wherein at low loads a regeneration circuit is turned ON for substantially an entire current-transfer cycle such as to avoid output of current-fed converter continuing to rise; and ii) wherein at high loads the regeneration period is reduced to between about &#xbc; to &#xbd; of a resonance-frequency cycle so that a resonance between the regeneration capacitance and the transformer's leakage inductance avoids excessive ringing currents and/or lost efficiency.

Active clamp resonance control

A power converter includes a current source providing an input current, a transformer having primary and secondary windings, a switch network coupling the current source and the primary winding, and a clamping circuit coupled to the switch network. An output bus is coupled to the secondary winding and provides an output voltage. A control circuit has inputs based on the output voltage and the input current, and generates switch network control signals based on those inputs. The control circuit also generates clamping circuit control signals based on the switch network control signals. The power converter may also include a start-up control circuit configured to selectively control the switch network and the clamping circuit so as to raise the output voltage to a desired level. In some embodiments, the switch network is a full bridge, and the clamping circuit includes first and second clamping switches.

Power conversion circuit with clamp and soft start

A control equipment for a resistance welding machine for welding a material by the Joule's heat generated in the material by applying an electric power to the material, including an inverter for converting a DC voltage to an AC voltage by pulse width modulation control, a transformer having a primary winding to which the AC voltage is applied and having a secondary winding which supplies an AC current to the material, and a control unit for generating an AC current reference with a rectangular waveform of a specified frequency, comparing the AC current reference with an output current of the inverter to obtain an error, and for PWM controlling the inverter so that the error becomes zero.

Growing community of inventors

Tokyo, Japan

Tatsuaki Ambo