Research on symmetrical output control strategies for Three-phase high power sine wave inverter

In terms of the conventional inverter doesnpsilat match all unbalanced loads, a topology and strategy of nature-decoupling in circuit and magnetic circuit is proposed for aeronautic and military equipment field. Voltage is controlled independently by double-loop of voltage current instantaneous feedback and PI controller. Closed-loop control can be done by PLL respectively in each phase, to make the output voltage and phase track the references. Pulse width and phase of reference sine are modulated by voltage-loop and phase-loop which ensures the inverter phase and voltage to symmetry. In this paper, output unsymmetrical mechanism of a traditional inverter is analyzed, main circuit topology, construction of voltage current feedback circuits, control principle and implementation method are discussed, and its models are set up and analyzed. Simulation and experiment results of 30 kW three-phase inverter show that the circuit design is feasible. Satisfied effect is achieved by this means.