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

The paper presents an active power filter (APF) 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 an energystorage capacitor. Since the energy change in the energy-storage capacitor can be compensated in the next cycle, and a larger DC bus voltage ripple can be tolerated if a sampling technique is used, 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 veriffied by using a PSPICE simulation and experimental results.