A new single-phase active power filter with reduced energy storage capacitor

This paper presents an APF (active power filter) circuit which employs a new control method, using an integration and sampling technique, to simplify the calculation algorithm for the real fundamental component of load current. In addition, a new simple control scheme, based on the energy balance concept, is proposed to control the voltage of energy storage capacitor. Since the energy change in the energy storage capacitor can be compensated in the next cycle and larger DC bus voltage ripple can be tolerated by using the sampling technique, a relatively smaller energy storage capacitor is required. The advantages of this APF circuit are simplicity of control circuits, low cost (a smaller energy storage capacitor) and good transient response. In theory, the time delay for the compensation of reactive power and harmonic currents is zero. The feasibility of this theory is verified by using a PSPICE simulation and experimental results