Development and Testing of Wavelet Modulation for Single-Phase Inverters

This paper introduces a novel modulation technique for single-phase (1 phi) voltage-source (VS) dc-ac power inverters. The proposed modulation technique is based on a newly designed scaling function that is capable of supporting a nonuniform recurrent sampling process. This scaling function generates sets of basis functions that span spaces, of which a collection constructs a nondyadic-type multiresolution analysis. Furthermore, the newly designed scaling function has a dual synthesis scaling function that is designed to reconstruct continuous-time signals from their nonuniform recurrent samples. The proposed wavelet modulation technique is implemented using a MATLAB code that generates switching pulses to activate a SIMULINK model of a 1 phi VS four-pulse (H-bridge) inverter. Several performance tests are conducted for the proposed wavelet-modulated (WM) inverter, when supplying linear, nonlinear, static, and dynamic loads. The results of these tests show significant reduction of the output harmonics along with high magnitude of the output fundamental component. The efficacy of the proposed WM inverter is further demonstrated through a comparison of the random pulsewidth modulation (RPWM) and the pulsewidth modulation (PWM) inverters for supplying the same loads. The comparison results show that the proposed WM inverter is capable of producing outputs with higher quality than the RPWM and PWM inverters.