Voltage type harmonic source and series active power filter adopting new control approach

The harmonic characteristics of a rectifier with a filter inductor or capacitor on the DC side are analyzed and then is classified into current or voltage-type harmonic sources. The reason why the series active power filter is suitable to compensate voltage-type harmonic sources is illustrated. A new control approach of detecting load voltage is developed. It can directly obtain the load voltage harmonic component to provide the reference voltage for the series APF and improve its compensation performance. In addition, the control method of the PWM inverter and a method to keep its DC side voltage constant are discussed. Experimental results, from a complete prototype of the series APF, are presented to show its validity for compensating voltage-type harmonic sources, and validate and compare the control approaches.