Inverter control technology based on multi-resolution wavelet modulation

In order to realize a more rigorous inverter modulation method, and improve the frequency spectrum of output harmonic so as to reduce system EMI, a multi-resolution wavelet modulation (WM) technology is presented. In this research, inverter modulation behavior is modeled as a non-uniform recurrent sampling and reconstruction process, this process is realized through a multi resolution analysis (MRA) which is constructed by basis functions of a combined Haar wavelet. Simulation results show that, compared with traditional SPWM inverter, the frequency spectrum of output harmonic is spread to a wide and relatively continuous frequency band from integral multiples of switch frequency, which can effectively reduce system EMI.