Intelligent Ultrasonic Power Supply Based on HPWM

Aims: The design of the ultrasonic power supply based on HPWM was researched and developed to reduce the switching loss of high frequency switch and its harmonic distortion in this paper, which the performance of whole system is highly improved.
Study Design: An improved control scheme named hybrid pulse width modulation (HPWM) is proposed, in which TMS320F2812 is used as the main control chip, the HPWM control signal is generated by using a voltage and current double closed-loop PI controlling method.
Place and Duration of Study: Jiang Nan University, Key Laboratory of Advanced Process Control for Light Industry, in Wuxi, Jiang Su Province between June 2012 and July 2013.
Methodology: Two set of experiment about our research including hybrid pulse width modulation (HPWM) and traditional sinusoidal pulse width modulation (SPWM) are carried out. Device parameters of all parts were calculated precisely and the device numbers were chosen after several experiments. A ultrasonic power supply System based on HPWM was designed finally.
Results: According to the theoretical analysis, a 3KW Ultrasonic power supply is developed and the resonant frequency is 25KHz, using the hybrid PWM and double closed-loop control strategy proposed in this article. The power is tested successfully. The power experiment shows the system works well and gets high stability.
Conclusion: The experiment result shows that the system works well and the switching loss of high frequency MOSFET and its harmonic distortion are effectively reduced. The design of the ultrasonic power supply based on HPWM has high value of application.