Bipolar reference for PWM control of a single-phase shunt hybrid power filter

In this paper, a new bipolar reference control is applied to a single-phase shunt hybrid power filter (SPSHPF). It is implemented with pulse width modulation, PWM, in order to compensate harmonics and reactive power generated by non-linear loads. This method uses a residual signal constructed from the comparison between the supply current and its desired value. The SPSHPF includes power factor correction capacitor connected in series with a transformer. A single-phase current controlled voltage source inverter feeds the primary winding of the transformer. The PWM control technique adopted is based on two comparisons of a triangular high frequency carrier signal and the source harmonic current. This harmonic signal namely +ϑ and its negative value -ϑ are used, at the same instant, in the comparison process to generate the gate signals of the semi-conductor devices. By using the averaging technique, a direct consequence of this proposed PWM control is that the transfer function of the SPSHPF becomes a pure gain. Simulation results using power system blockset toolbox PSB of Matlab verified the effectiveness of the proposed control algorithm.