Study On Input Series And Output Interlaced Parallel Power Supply With Adjustable Current

With the development of power electronics technology, The demand of power supply technology is more increasing. According to different applications, different circuit structures are used in current source. Aiming to use the Wire Cut Discharge Machining machine with three-phase AC voltage, an input-series and interlaced output-parallel power supply with adjustable current is proposed in this paper.Input-series and output-parallel dual-switch forward converter is used in preamp topology presented in this paper. Adjustable size current source is configured. The voltage stress of the input side switches is reduced by half, thus the MOSFET with low withstand voltage and low on-resistance can be chose to replace IGBT to reduce the power loss,improve the switching frequency and reduce the volume of the transformer and filter inductor. Meanwhile, the small equivalent duty cycle, high secondary diode voltage stress,the output current ripple and other shortcomings are overcame. In this paper, on the front-end converter under the condition of different duty ratio of work mode has carried on the detailed analysis. SG3525 is used as the front-end converter control chip. And the design of the constant-current source is elaborated in detail.The current pulse conversion circuit is the stage of power. The current pulse is adjusted, according to the requirements of Electrical Discharge Machining(EDM). The working principle of the post-stage circuit is elaborated in detail. And different load conditions are analyze. The touch screen used as the display and input devices and STM32F103ZET6 used as the control core are achieving the communication through the RS232 protocol. The mixed control of the EDM power supply is realized.Through theoretical analysis and simulation, the parameters of the converter aredetermined, and accordingly the hardware circuit design is completed. Finally, based on the above theoretical analysis and proposed design method, a prototype is developed. At last, the experiment is tested to verify the theoretical analysis and the effectiveness of the control strategy.