The Synthetical Compensation Research on High-order Harmonic and Reactive Power

With the continuous development of water-saving irrigation, agricultural product's deep process, greenhouse control in the agriculture, more and more variable frequency equipments, rectifier devices and other power electronic equipments have been used. But owing to the use of these equipments, harmonic pollution problem in power grid is more serious. Active filter is an effective method to the pollution now. Based on the instantaneous reactive power theory, a new way to detect both instantaneous reactive current and high-order harmonic current is proposed. By this way the high-order harmonic and fundamental reactive power are synthetically compensated. Our studying group has developed a synthetical active filter system, which uses the large power transistor as the main circuit, TMS320F240 processor as controller, and connects possible LC power filter and active power filter in series. The experiment results show that the system can effectively filter 5,7,11 degree-order current harmonics and prove that the way is correct and feasible.