Inverter Power Supply Wireless Paralleling Control Study

The wireless parallel operation of inverters, which can meet the high reliability requirements for power supply, is one of redundant parallel control method of power supply. Its corporation and exit operation of parallel system is very simple, with some incomparable advantages over traditional inverters, so that it has widely application prospect in electricity power supply. However, as its current sharing control strategy is more complex, the active power and reactive power sharing in parallel system is not very ideal, which seriously restricts the application of wireless parallel operation of inverters. Therefore, how to solve the problem of power sharing in inverters parallel system is the key to achieve wireless parallel operation.This paper identifies the model of inverter's main circuit firstly. Then, output filter and its control characteristics are designed. At the first this paper designs SPWM controller based on double feedback of voltage and current. Using Simulink in MATLAB, the model of single inverter system based on double feedback of voltage and current is identified Simulation analysis result shows that dynamic and steady state performance is better.Based on the mentioned model, this paper designs parallel inverter system, analyses its characteristic of active power and reactive power, and studies on the harmonic circulating current control strategy by adding coupling inductance to inverter's output. According to PQ external characteristic droop principle, inverter's output voltage amplitude and phase can be obtained by regulating active power and reactive power. Meanwhile, new droop control strategy using derivative element is used in this system, and its signification parameters are educed on the basis of frequency-active power, amplitude-reactive power relationship curves. Simulation analysis shows that dynamic and steady state performance of parallel inverters system is better, and circulating current between modules can be restrained obviously. Depending on the mentioned control strategy, wireless parallel operation inverters system based on DSP is set up in this paper, as experimental hardware circuit and software design flow chart are presented.