Research On The Power Supply Without Transformer In Electic Vehicle Conversion Circuit

With the energy problem has become increasingly serious, Electric Vehicle, representation of new energy automobile, has received more and more attention. The vehicle power supply conversion systems of electric vehicles, the core of them, usually consist of a high-frequency transformer or a power frequency transformer, which has many flaws such as large volume, high cost, and unavoidable leakage flux and loss from Magnetic core and winding resistance of transformer, what’s more, electromagnetic interference problem exists badly. Non-isolated transformerless switching circuit, however, which is characterized by small and light, low cost and high integration, is suitable for applying on electric vehicle power converters.Electric vehicle include one with low voltage power system and the other with high voltage power system. The low voltage power supply system mainly involves in the vehicle mounted power supply system, provides the electric energy for all kinds of vehicle mounted instruments and equipments. For the one with low voltage power system, in this paper, a transformerless Single Input Multiple Output (SIMO) DC-DC converter was designed. The topological structure of the SIMO converter was presented here, besides, in this article the PID-SMC algorithm was introduced to realize the feedback control of the SIMO converter. After a SIMULINK platform of transformerless SIMO converter was established as well as a hardware prototype based on DSP digital control core is built, the experimental result was analyzed and compared. The main research contents of this paper were listed as follows:(1) The realization method of transformer circuit topology and the control algorithm of DC-DC converter are analyzed and compared.(2) This article researched and analyzed the working principle of the transformerless SIMO converter, and had finished designing the main parameters from the SIMO topological structure. Here also studied the function principle of PID-SMC control algorithm, the implement method with DSP, and set up a SIMULINK platform for verifying theory analysis.(3) Based on the theory analysis above, the paper presented the hardware model machine with a transformerless SIMO converter, designed the hardware parameters, and accomplished choosing every device. At the same time, here presented the digital realization of the DSP based PID-SMC algorithm.(4) Finally, the simulation and test results are compared and analyzed, which proves the feasibility of the theory.Based on the theory analysis of transformerless SIMO converter and the analysis of experiment results, the SIMO converter controlled by PID-SMC performs well. And after connecting hardware platform with external electromotor and LED load, we can demonstrate its feasibility on electric vehicle on-board equipment.