Research On High-frequency Pulse Power Supply Based On Microcontroller

With the progress of industrial technology,electrolytic machining process is widely used in aviation,aerospace and other equipment manufacturing industries,and the stability of the output waveform of the pulse power supply,as one of the core equipment of electrolytic machining equipment,directly affects the machining accuracy of the workpiece and the surface quality.Research and development of high efficiency and stability of high frequency pulse power supply is conducive to the development of electrolytic processing process.In this article,according to the processing requirements,based on the characteristics of electrolytic processing process,the efficiency,volume and weight of the power supply,as well as the follow-up research,a high-frequency pulse power supply prototype was developed.Its performance parameters are voltage 5V～30V,current 0A～20A,output pulse frequency1KHz～20KHz,adjustment step is 1KHz,output pulse width is 0.1～0.9,adjustment step is0.1.The scheme used is a front-stage full-bridge inverter plus a back-stage DC chopper output,where the utility power is rectified,filtered,inverted,converted to high frequency,rectified and filtered again,and then chopped to output pulse voltage.Power supply development includes two parts: hardware and software.The hardware mainly includes: full-bridge inverter circuit,pulse signal modulation circuit,protection circuit and high-frequency transformer design.The integrated PWM chip UC3846 modulates the output of two mutually opposite pulse signals to control the full-bridge inverter circuit.The software part is used to control the frequency and pulse width of the output waveform,including the key program,display program,PWM program,pulse parameter setting,etc.The main purpose is to control the DC chopper circuit by modulating the output pulse signal with specified frequency and duty cycle through the program and STM32 timer.When testing the prototype,the basic performance of the prototype is first tested with a high-power load,and the voltage waveforms at both ends of the load are tested by Tektronix analog oscilloscope for comparison and analysis with the set parameters.The output voltage and current were adjusted to the maximum,the frequency and duty cycle were adjusted,and the output waveform was observed.Based on the pulse waveform,it was judged that the prototype basically achieved the expected design goal and could be used for electrolytic processing.Finally,the actual processing was carried out to confirm that the prototype could operate stably for a long time and the protection circuit could respond quickly.