Switching Power Supply And Its Applied Research On The Control System Of Railway Vehicle Electric Door

Switch power supply, with the advantages of small package, high efficience,wide stabilizing range, etc. has been rapidly substituted for traditional linear powersupply and vastly applied in various of electronic devices, one of which is a kind offlyback power supply being used in the occasions of less power and multiple outputs,because of its simple topological structure and less demand for peripherals.In the paper, on the basis of deeply analyzing the operation principle and thecontrol method of the main circuit topology, the ZCS-PWM flyback switch powersupply of the110v transforming+5v、±15v、+48v is designed, which has a goodperformance and12w output power. Its work efficiency is high and theelectromagnetic compatibility is better. It can satisfy the requirements of switch powersupply of the railway vehicle electric control system. The improved power supply ismainly used in the railway vehicle as the power supplier of controller system anddriver system and in the other occasions of various sampler circuits. In this paper themain research contents and results are as follows:1. To study the commonly used DC-DC switching power supply topology whichare analysized and compared by PSIM software and control methods and combinedwith the specific requirements of this design, the design of the flyback switchingpower supply for PWM type topology structure is selected.2. On the basis of the EMI problems of switch power supply and pointing outwhat circumstances will produce electromagnetic interference in switch power supplyand introducing several effective methods to restrain electromagnetic interference.Finally, we introduce the function of the soft switch technology in the role of inhibitionof electromagnetic interference.3. Through the analysis and comparison of the working principle and advantagesand disadvantages of the flyback converter with buffer circuit, ZCS-PWM flybackconverter designed in the paper is given. It adds an auxiliary circuit on the basis of thetraditional flyback converter and realizes the opening and shuting of the zero currentcondition of the primary switch and auxiliary switch, the other passive power devicesalso realize the soft opening and soft shut off. So it can effectively restrain the stress ofpower switch’s voltage and current and reduce the switching loss and EMI and improve the efficiency of the converter.4. Using the Altium Designer software to draw out the overall design scheme ofswitch power supply, the main circuit, control circuit and the feedback circuit aredesigned in detail. Then traditional flyback converter and the new flyback converterbeing designed in the paper use the PSIM software to simulate. The results of thesimulation verify the rationality and feasibility and finally use Altium Designer tomake PCB plate in this paper.