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公开(公告)号：US11953530B2
公开(公告)日：2024-04-09
申请号：US17259195
申请日：2020-01-30
发明人： Yasuaki Mitsugi , Takashi Shigemasa
摘要： 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 unit.
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公开(公告)号：US11933825B2
公开(公告)日：2024-03-19
申请号：US16973437
申请日：2020-01-30
发明人： Yasuaki Mitsugi , Takashi Shigemasa
摘要： 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. The frequency calculator includes a rate limiter in series with the arithmetic unit, the rate limiter limiting a change of the system frequency equal to or greater than a prescribed change rate.
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公开(公告)号：US11965917B2
公开(公告)日：2024-04-23
申请号：US17791221
申请日：2020-10-06
发明人： Yasuaki Mitsugi , Takashi Shigemasa
IPC分类号： G01R21/133 , G01R19/25
CPC分类号： G01R21/1331 , G01R19/2513
摘要： 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 AC power.
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公开(公告)号：US11982696B2
公开(公告)日：2024-05-14
申请号：US17755931
申请日：2020-05-26
发明人： Yasuaki Mitsugi , Takashi Shigemasa
摘要： 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.
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