Patent ID: 11953530
Assignee: TOSHIBA MITSUBISHI—ELECTRIC INDUSTRIAL SYSTEMS CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H  Y | IPC G  H

Claim 9:
10. A power conversion system, comprising:
a system frequency detector to detect a system frequency of a power system being connected to a distributed power source; and
a power convertor to operate power conversion based on the system frequency of the power system,
wherein the 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,
wherein the system frequency detector includes frequency calculation circuitry including an angular frequency calculator, an arithmetic calculator, and a low-pass filter,
wherein the angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal after calculating the moving average generated by the orthogonal coordinate signal generator, and
wherein the arithmetic calculator calculating a system frequency of the power system from the angular frequency by multiplying the angular frequency by ½π,
wherein the low-pass filter is provided in series with the arithmetic calculator, the low-pass filter suppressing a high frequency component of the system frequency.