基于PI-PLL的全桥移相式超声电源设计

Design of Full-bridge Phase Shift Ultrasonic Power Supply Based on PI-PLL

针对传统超声频率跟踪系统锁相范围窄,电源启动或负载突变时易失锁等问题,提出了一种将数字PI控制器与锁相环(PLL)电路相结合的复合式频率跟踪策略。该策略通过PI控制器进行频率粗调,通过PLL电路进行频率精确修正,并对超声电源的主电路、脉冲变压器隔离驱动电路和保护电路进行了设计及详细分析。最后,通过实验证明了该电源具有性能稳定,频率跟踪特性好和功率因数高等优点。

Some defects are found in traditional ultrasonic frequency tracking system,such as the narrow locked-in range and the tendency to lose phase-locked with a sudden change in load,etc.Therefore,this paper proposes a composed control strategy which combines a digital PI controller and refined tracking via PLL circuit.The main circuit,drive circuit and protection circuit are designed and analyzed.The experimental results prove that the power supply has the advantages of stable performance,good frequency tracking characteristics and high output power factor,etc.