基于FPGA的宽频超声波电源频率跟踪系统设计

Research on frequency tracking system of wide-band ultrasonic power supply based on FPGA

针对传统超声波电源无法驱动及锁频不同谐振频率段的换能器,实现不了宽频域内的锁相和频率跟踪的问题,设计了一种基于FPGA的具有自动频率搜索与跟踪、动态匹配不同谐振频率换能器的宽频域超声波电源。根据换能器的阻抗特性曲线,设计出动态步长的宽频域频率搜索方法,快速跟踪到换能器的谐振频率,并根据反馈电路的电压电流相位差,实时调整输出频率,锁定整个系统工作在谐振状态。实验结果表明,设计的宽频域超声波电源频率搜索快、跟踪准,动态匹配换能器适应性好。

For conventional ultrasonic power supply,there exists problems of driving and locking of different frequency transducer, and the problems of wide-band phase locking loop and frequency automatic tracking,a new type of wide-band ultrasonic power supply with frequency automatic searching and tracking,dynamic matching different ultrasonic transducers has been developed based on Field-Programmable Gate Array（FPGA）.According to the impedance characteristics of the transdueer,a new method with dynamic step has been designed to search the resonance frequency of the ultrasonic transducer and then the master processor real-time ad- justs the output frequency,locks the system at resonance state according to the phase of voltage and current from the feedback cir- cuit.The experimental result shows that the design of the wide-band ultrasonic power supply has the advantages of quick frequency searching and accurate frequency tracking,and it also improves the adaptability of dynamic matching of different transducers.