用准同步离散Hilbert变换测量无功

Reactive Power Measurement with Quasi-synchronous Discrete Hilbert Transform

由电路理论知Q =1T ∫2π0 u(x - π2 )i(x)dx。u(x - π2 )即为电压信号移相 - 90°,而Hilbert变换正好满足此要求。为便于计算机计算采用离散Hilbert变换。由采样误差或者电网频率发生漂移导致的测量误差可以采用准同步方法提高精度。

According to the circuit theory,Q=1T∫^(2π)_0u(x-π2)i(x)dx.u(x-π2)is the voltage signal with a -90° phase shift,which the Hilbert transform can meet with. In favor of the computing on computer,the discrete Hilbert transform has been used. The measuring error, which is caused by the sampling error or electrical-net frequency drift error,can be overcomed, to a certain extent,by the measurment techniques with quasi-synchronization. The measuring accuracy of reactive power can be highly acquired with quasi-synchronization discrete Hilbert transform.