Implementation and Simulation of a Modified PWM with Two Current Control Techniques Applied To A Single-Phase Shunt Hybrid Power Filter

In this paper, direct and indirect current control strategies are applied to a single-phase shunt hybrid power filter (SPSHPF). They are implemented with a modified pulse width modulation (M-PWM) in order to compensate the harmonics and reactive power generated by non-linear loads and the high frequency harmonics generated by the switching process. Contrarily to the existing methods, the proposed indirect current control eliminates switching spikes in the supply current and appears to be more suitable than the direct current control method, especially when compensation is required. Furthermore, the M-PWM technique ensures the elimination of all groups of harmonics that are centered on the odd multiples of the switching frequency. It requires a relatively reduced input filter. In addition, it attenuates the rays that are located around twice the switching frequency four times less than the S-PWM. The measured power losses of the M-PWM hybrid filter are also four times lower compared to the standard PWM control. Experiment results obtained from a 1 kVA laboratory system and simulations carried on using the power system blockset (PSB) toolbox of Matlab verify the effectiveness of the SPSHPF adopting the indirect current control with the modified PWM technique