The Research And Design Of Automotive Inverter Power Based On DSP

With the popularization of intelligent automobiles and the development of science and technology,automobiles have become a kind of transportation tool integrating office and entertainment.People will load more electronic devices in cars to improve their quality of life,such as car-mounted televisions,refrigerators and Humidifier,etc.At the same time,they will also use mobile electronic devices such as notebook computers,tablets and mobile phones in cars.All these devices need 220V/50Hz power supply,but only 12V DC voltage can be provided in the vehicle.Therefore,it is necessary to design a reliable and safe vehicle-mounted inverter power supply.This paper designs a vehicle-mounted inverter with TMS320F28335 as the main control chip,which converts 12V DC voltage to 220V/50Hz AC voltage.According to the design requirements,a two-stage conversion circuit structure is adopted,including a front-stage DC-DC push-pull boost circuit and a rear-stage DC-AC full-bridge inverter circuit.Firstly,the DC-DC push-pull boost circuit of the previous stage is studied and designed.SG3525 chip is selected as the main control chip of the push-pull circuit.In order to stabilize the output voltage of the push-pull circuit,the voltage closed-loop control is adopted.At the same time,the input overcurrent and under-voltage protection design combined with software and hardware is added to improve the safety of the power supply.Secondly,the research and design of the DC-AC full-bridge inverter circuit of the latter stage are carried out.Based on the analysis of the mathematical model of SPWM inverter circuit,the double closed-loop PI control strategy of output voltage outer loop and current inner loop is adopted.The control strategy of the system is simulated by MATLAB simulation software.The simulation results verify the correctness of the system design scheme and control strategy.Finally,the control system of vehicle-mounted inverter power supply based on DSP is designed,including hardware circuit design such as inverter drive circuit,sampling circuit and protection circuit,and software design such as A/D sampling program,SPWM wave generation program and PI adjustment subprogram.Based on the simulation and circuit design of the vehicle-mounted inverter power supply,a 500W experimental prototype is built and various performance indexes are tested.The test results show that the various indexes of the vehicle-mounted inverter power supply designed in this paper meet the design requirements.