基于DDS-PLL超声波电源的频率自动跟踪研究

Research on the Frequency Automatic Tracking in Ultrasonic Power based on DDS-PLL

针对超声电源负载系统工作过程中的频率漂移问题,提出了一种基于直接数字频率合成(DDS)与锁相环(PLL)相结合的粗精频率复合跟踪控制策略,即通过DDS技术实现频率的粗调;通过PLL硬件电路实现频率的精调。试验结果表明,研制的超声电源系统具有频率跟踪速度快,跟踪准确的优点,并能实现振动系统的恒定振幅输出,可实现系统的稳定、高效运行。此外,逆变器的输出功率因数接近1,提高了整机效率。

The paper presents the rough and refine control method which based on the DDS-PLL for frequency tracking against the frequency drift problem during the ultrasonic power system operation.The method includes rough tracking by DDS and refined tracking by a PLL hardware circuit.The the experimental result proved that the developed ultrasonic power system can realize quick and accurate frequency tracking ,and can work well with constant amplitude control.Also, it can make the vibrate system worke stably and efficiently,and the output power factor of the inverter can be nearly to unit, which improves the efficiency of the system.