Design And Research Of Three-phase And High Power Charge And Discharge Device

With the development of power device and power control technology battery charging system is evolving into characteristics of high frequency, high efficiency, and miniaturization. Therefore, in this thesis a lot of research on PWM battery charging system has been made and a kind of battery charging system with high efficiency, high power, and power saving is designed aiming at meeting practical demand.Three-phase half bridge rectifier circuit is used as the main circuit. It can charge and discharge 18 batteries of 3A simultaneously and a sort of control system is designed so that bidirectional flow of energy is realized. In this thesis, the emphases of discussion are placed on operating principle of three-phase half bridge, from which the condition of three-phase half bridge working under two-phase situation is gained on which a kind of reliable SPWM control algorithm is induced and the control structure is shown. The analyses are concentrated on the characteristics and its control algorithm of the structure mentioned above, here three effective control algorithms are given and comparison is made among them whose effects on the whole system are shown in the last chapter. Following these a brief introduction to design of and research on direct current part is made, combined with the characteristics, function, and basic DC/DC inverter of inversion part, a sort of direct converter whose voltage can be set up or down is designed and its control structure is given in which the control algorithm analogous to the counterpart in inversion module is taken.A sort of control scheme combined digital and analogous strategy is brought into the control system. Here several kinds of important hardware design methods are the focus, whose characteristics and operating principle are analyzed for the sake of convenience of corresponding software design. A detailed analysis of software design method of the inversion control system based on TMS320LF2407A is made, meanwhile detailed program flow chart and its implementation scheme of each module is also shown followed by a brief introduction to 96MCU-based direct control system and the program design mode of high-level industrial control computer.The test results and waves of the system are shown, which demonstrate better input current tracking performance can be achieved with the control scheme mentioned in this thesis, the inputs power factor is close to 1 and the output direct bus voltage of the converter is stable and reliable. In the alternating current control system, using PI regulator of speed change integral can achieve the control performance index such as small overshoot, non-oscillating state, and no steady-state error on condition that control sampling period of DSP is equal to that of alternating current power.