Research Of Direct Power Control Based3-Phase Charge-Discharge System Design

Before storage batteries are put into the market, they will be charged and discharged forseveral times in the factory to get the best performance. Focus on this, a whole implementingscheme is designed in this thesis.System with efficient charge-discharge management, based on a3-phase unity powerfactor rectifier, multi bidirectional DC chopper circuits, CAN bus, and a monitoringcomputer is presented in this thesis. IGBT based3-phase full bridge rectifier and itsmathematical model and principle is introduced in detail. Then the condition that the invertercan operate under four-quadrant is discussed and showed. Especially focus on direct powercontrol method that used in this thesis, its principle and realization are analyzed. Thedisadvantage of classical direct power control, that the instantaneous reactive power is out ofcontrol in even number sectors under certain condition, is pointed out. An improvingswitching table and corresponding system structure is inferred and presented. Simulationbased on matlab/simulink is given out. The results showed that, compared with classicaldirect power control, the method of this thesis got better performance on harmonicsuppression on the input currents of the inverter, while other performance indexes wereroughly the same.According to system requirements, Hardware design of main control board based ondigital control of the system is presented, and TMS320F2812is used as core controller. Themain circuits of the control board are given out. Also their functions and principles arediscussed. A new experimental platform scheme suitable for the presented system and thesoftware design are presented. And the program flow charts of main program and directpower control are showed and discussed.