Research On The Design And Control Method Of Combined Multi-function Three-Phase Inverter

With the growth of energy demand, conventional energy reserves are depleting.In order to save energy and reduce environmental pollution, commercial development of clean energy has been treated as central issue. However, the electricity produced by new green energy are mostly DC voltage. And it needs to be converted into alternating voltage, thus people can use it in daily life. Therefore, the inverter device is required.So this paper uses dsPIC33EP512MU814 as main control chip to design a kind of combined three-phase inverter. It can work in single phase mood, and can also achieve a symmetrical three-phase AC output through the combination of three inverters. In addition to flexibility, it has a stronger ability of resisting three phase unbalance load. Thus, it is of great value in practice. The main content is as follows:(1) Based on the analysis of various existing topology structure, choose the inverter topology and the closed loop control strategy, according to the specific needs of the subject.(2) Choose unipolar double frequency SPWM modulation method to control the switches, establish the mathematical model, and complete the simulation of three-phase inverter system in MATLAB/ Simulink.(3) Analyze the cause and harm of transformer DC biasing, and inhibition of DC current component is completed through software programming. Besides, in order to prevent the switches being on all the time, the dead time is added in the pulse width modulation. Thereafter, the hardware method is adopted for the compensation(4) Complete the hardware circuit and the software design of the system. The algorithm writing of unipolar multiplier SPWM modulation and PI dual loop control is the focus. And the function of each part is debugged.(5) Set up the inverter experimental platform, complete open-loop experiment.Then the feasibility of system implementation is verified.