中文摘要：

传统超声加工电源不具备多频率段自动跟踪的特点，其在工作过程中存在频率跟踪精度过低的现象，而且传统超声波电源的结构决定其输出频率特性单一，无法驱动不同频率特性的超声波换能器。对此采用搜索电流最大值技术与基于数字信号处理器（DSP）TMS320F2812的软件锁相技术结合的复合频率跟踪策略．以直接数字式频率合成（DDS）芯片作为输出频率源，实现自动查找换能器谐振频率及频率自动跟踪的功能，依据超声波换能器的反馈信息同步调节功率和阻抗匹配网络，动态响应不同特性的超声波换能器，维持恒振幅输出。给出具体实现方法，通过实验验证该方法的可行性和有效性。

英文摘要：

The conventional ultrasonic machining power supply does not have the automatic tracking of multiple fre- quency bands, as well as the phenomena of low frequency tracking accuracy exists in the work, also because of the conventional ultrasonic power structure determines single of the output frequency characteristic, lead to it can not drive the ultrasonic transducer of different frequency characteristics.Therefore ,with the strategy of combining a com- posite frequency tracking which is search maximum current technology and based on digital signal processor （DSP） TMS320F2812 software lock-in technique,with direct digital frequency synthesis（DDS） chip as the output frequency source to achieve automatically find the resonant frequency of the transducer and frequency automatic tracking func- tion, based the feedback of ultrasonic transducer synchronous regulator power and impedance matching network to dy- namic response different characteristics of ultrasonic transducer,so add to maintain constant amplitude output.A spe- cific strategy is given to verify the feasibility and effectiveness of the method.