A single-phase active power filter with double-edge integration control

A control method for a single-phase active power filter (APF) is presented. The proposed method controls a half bridge shunt APF based on double-edge one-cycle control and mains current sensing. The half-bridge APF is connected in parallel to one or a group of nonlinear loads. The control goal is for the half-bridge APF to produce reactive and harmonic current that cancels the one generated by the nonlinear load. This control method dose not need to create a current reference, hence the burdensome obligation of dynamically sensing the load current as well as calculating the harmonics and reactive current components of the load, as required by most previously reported control methods, is eliminated. The control circuit contains an integrator with reset along with a few linear and logic components. No multipliers are used. No input voltage sensor is required. The operation switching frequency is nearly constant in most of the load range that is desirable for industry applications. The control method features wide stability, great simplicity, high reliability, and low cost. A 200 W prototype was built and experimental results are provided.