Application of a unsymmetrical PWM technique in harmonic compensators

In this paper a new PWM technique with optimized pulse pattern using unsymmetrical switching angles (OPUS) for low switching frequency is introduced. The calculation scheme of the OPUS technique and the control range of harmonics are presented. The technique is designed for use in an active power filter, by using as parallel compensation of the harmonic current or series compensation of the harmonic voltage separately. The successful operation is demonstrated by the simulation of a parallel compensator and a series compensator. The simulation results illustrate a good performance of the harmonics compensation. The technique is further validated by FFT analysis.