Research On High-Power Ultrasonic Power Supply Based On FPGA

Ultrasonic welding has easy operation, fast welding speed, high joining strength, high efficiency has in the industry of medical equipment, packaging, auto parts, electronics, and so widely used. However, the ultrasonic welding power supply equipment has the disadvantages of low frequency tracking, easy loss of load mutation and so on. Therefore, the design of high stability, frequency tracking speed, friendly man-machine interface ultrasonic power will have a very important significance. In this paper, the design of the 2KW ultrasonic welding power supply based on FPGA control is the target, and the design process is introduced in detail.Firstly, the principle of ultrasonic power supply system is briefly summarized. Then the hardware circuit of specific design, including the rectifier circuit, inverter circuit, a resonance matching circuit, high-frequency transformer, drive circuit, sampling circuit, protection circuit, pulse capture circuit, true rms converter circuit, communication circuit. In addition, the related parameters of the circuit are calculated and the process is selected.Then the overall structure of the ultrasonic power supply hardware is briefly introduced. And the hardware circuit is designed, including the rectifier circuit and inverter circuit and the circuit of the device parameters, the calculation of high frequency transformer parameters, drive circuit, sampling circuit, protection circuit, pulse capture circuit, true rms converter circuit, communication circuit.Then the design of the overall control scheme based on FPGA controller, and the control system is divided into several sub modules. The modules of AD module, sampling module, frequency sweep module, phase detector module, selector module, tracking module, RS232 communication module, PWM generator module are designed and verified. Then the human machine interface system of ultrasonic power supply is introduced and designed.Finally, the experimental platform of the ultrasonic power supply is built, and the driving signal, frequency tracking and power regulation of the ultrasonic power supply is tested, and the test results are analyzed.The experimental results show that the ultrasonic power supply is stable and reliable, and the frequency tracking is fast, and the expected results are achieved.