| Abstract |
A novel control scheme for the active filter, 'Component Separate PWM' is presented in this paper. This scheme has notable features both on the way of the compensating current generation and the harmonic component detection. The harmonic current is detected from the power line and is separated into its components by the digital spectral analysis of 'Moving Fourier Transform' or a least square estimation strategy. Thereafter the PWM signal is determined precisely against each of the detected component by the principle of the cosine crossing control with the time varying amplitude signal. These new methods enables to reduce the switching losses and realize high efficiency. Moreover the specified harmonic component that causes a serious interference to the network can be eliminated selectively and effectively. In this case, the active filter with the Component Separate PWM control scheme is regarded as a harmonic monitoring instrument connected to the electrical power system, which can flexibly control the global harmonic current flow in the power line. From the results of numerical case studies, this type of active filter shows good compensation performance even in the dynamic operation. |
