Abstract: A power measurement device includes: a first three-phase to two-phase converter converting a three-phase voltage signal of three-phase AC power into a two-phase voltage signal; a second three-phase to two-phase converter converting a three-phase current signal of the three-phase AC power into a two-phase current signal; an instantaneous power calculator calculating an instantaneous value of active power of the three-phase AC power and an instantaneous value of reactive power of the three-phase AC power based on the two-phase voltage signal and the two-phase current signal; a first moving average calculator calculating multiple active power average values of different moving average data quantities; a second moving average calculator calculating multiple reactive power average values of different moving average data quantities; and calculators that calculate average active powers corresponding to a frequency of the three-phase AC power, and the reactive power corresponding to the frequency of the three-phase A

Abstract: A power supply system for an independent system includes a plurality of power supply devices, a plurality of power conversion devices, and a control device, the plurality of power conversion devices are connected in parallel to the independent system, the plurality of power conversion devices are voltage source voltage-controlled, the plurality of power conversion devices convert power supplied from the plurality of power supply devices into alternating current power corresponding to the independent system, the plurality of power conversion devices supply the alternating current power after the conversion to the independent system, the control device controls conversion operations of the power of the plurality of power conversion devices, the control device calculates a plurality of active power command values of the plurality of power conversion devices according to active power required by the independent system, and calculates a plurality of reactive power command values.

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average. A frequency calculator calculates an angular frequency based on the two-phase voltage signal, and an arithmetic unit calculates a system frequency of the power system from the angular frequency.

Abstract: A power measurement device includes: a first three-phase to two-phase converter converting a three-phase voltage signal of three-phase AC power into a two-phase voltage signal; a second three-phase to two-phase converter converting a three-phase current signal of the three-phase AC power into a two-phase current signal; an instantaneous power calculator calculating an instantaneous value of active power of the three-phase AC power and an instantaneous value of reactive power of the three-phase AC power based on the two-phase voltage signal and the two-phase current signal; a first moving average calculator calculating multiple active power average values of different moving average data quantities; a second moving average calculator calculating multiple reactive power average values of different moving average data quantities; and calculators that calculate average active powers corresponding to a frequency of the three-phase AC power, and the reactive power corresponding to the frequency of the three-phase A

Abstract: 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.

Abstract: A power storage system includes multiple power storage devices, multiple power conversion devices, and a control device; the multiple power storage devices are capable of discharging and charging DC power; the multiple power conversion devices are connected to the multiple power storage devices and a bad, convert the DC power stored in the multiple power storage devices into power corresponding to the bad, supply the power to the bad based on the DC power stored in the multiple power storage devices, convert power of the load into DC power corresponding to the multiple power storage devices, and charge the multiple power storage devices based on the power of the load side; the control device controls a power conversion operation of the multiple power conversion devices. Accordingly, a power storage system and a control device are provided in which the power loss can be suppressed.

Abstract: 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.

Abstract: A system includes an orthogonal coordinate signal generator that generates an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency. A prediction calculator calculates a predicted value of the angular frequency after a time has elapsed based on the angular frequency and a differential of the angular frequency. In a state in which the phase jump of the power system is not detected, the frequency calculator calculates the system frequency based on the angular frequency. When the phase jump of the power system is detected, the frequency calculator calculates the system frequency based on predicted value for a constant amount of time.

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency, the frequency calculator further including a low-pass filter provided in series with the arithmetic

Abstract: A system frequency detector includes an orthogonal coordinate signal generator generating an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power by converting the three-phase voltage signal into a two-phase voltage signal orthogonal to the three-phase voltage signal, converting the two-phase voltage signal into a voltage signal of a rotating coordinate system, calculating a moving average of the voltage signal of the rotating coordinate system, and performing an inverse transformation of the voltage signal of the rotating coordinate system after calculating the moving average. A frequency calculator calculates an angular frequency based on the two-phase voltage signal, and an arithmetic unit calculates a system frequency of the power system from the angular frequency.

Abstract: A power generation system includes a plurality of photovoltaic cell panels for outputting DC power, a plurality of inverters for converting DC power into AC power, and a high-order device for communicating with the plurality of inverters. The high-order device is configured to acquire a predetermined power factor, and transmit a command value to each of the plurality of inverters so that the power factor corresponding to the predetermined power factor is achieved by a total output of the plurality of inverters. The high-order device is configured so as to determine a specific inverter that has room to increase the amount of reactive power output from among the plurality of inverters, to transmit a reactive power increasing command value for increasing reactive power to the specific inverter.

Abstract: A power generation system includes a plurality of photovoltaic cell panels for outputting DC power, a plurality of inverters for converting DC power into AC power, and a high-order device for communicating with the plurality of inverters. The high-order device is configured to acquire a predetermined power factor, and transmit a command value to each of the plurality of inverters so that the power factor corresponding to the predetermined power factor is achieved by a total output of the plurality of inverters. The high-order device is configured so as to determine a specific inverter that has room to increase the amount of reactive power output from among the plurality of inverters, to transmit a reactive power increasing command value for increasing reactive power to the specific inverter.