Integrated power factor compensator based on sliding mode controller

Active power filters are an important means to increase power quality, due to wide use of nonlinear loads and switching mode power converters. The paper presents a simple control strategy which has employed the switching mode rectifier to work simultaneously as a power factor corrector and an active power filter, to decrease current harmonics drawn from a nonlinear load. As no additional active power filter is needed, the cost of this configuration is lower than that of the conventional active power filter configuration. A sliding mode controller is used in the current control loop to achieve fast dynamics. Only the source currents have been measured in the proposed control scheme to reduce the elements of current sensors needed in the conventional control approach. A simple proportional-integra1 controller is adopted in the voltage control loop to achieve slow dynamics. The proposed scheme can acheve high power factor, current harmonic elimination and no dedicated active power filter. A diode rectifier feeds the capacitive load as the nonlinear load is taken on AC mains to demonstrate the effectiveness of the proposed active rectifier for reactive power and current harmonic compensation.