In order to meet the demand of electricity users and power electronics manufactures

this paper presents a novel variable current technology control principle for natural soft-switching in order to develop the natural soft-switching act-state for the three-phase inverter.The novel three-phase inverter with this technology is used as an inverter of active power filter for harmonic compensation because of its simple circuit structure and reliable control.The topological structure of the inverter and the variable current technology for natural soft-switching are investigated.Based on the analysis of the main circuit

a space voltage vectors method is proposed for a AC/DC/AC inverter.The way to implementing digital control is presented by means of the space vectors pulse-width modulation method of indented carrier

according to the characteristic of the topology.Simulation result demonstrates the correctness and feasibility of the proposed technology.