Application of Wavelet Transform Circuits for Harmonic Analysis in Power Systems

This paper proposes a new method based on continuous wavelet transform circuits for the analysis of harmonics in real-time. To measure harmonics, the wavelet transform of harmonic signal is realized by analog CMOS VLSI composed of analog filter bank, whose impulse response is Morlet wavelet. Nonlinear least square method is employed to obtain the transfer function of the filter with CMOS log-domain integrators as main building blocks. By changing the values of the integrators bias currents, this circuit can realize various scales wavelet transform of harmonic signal. Simulation results report that the implementation of continuous wavelet transform by analog circuits provides accurate and fast harmonic analysis in power systems.