A novel robustness matching method based on amplitude-frequency characteristic for high power ultrasonic system under variable load

•High robustness in driving current facing pressure load of the transducer.•Introduce the uncertainty in the parameter calculation, and can cover the stability of whole working process.•Low computation and easy to realize.•Wide application potential in cleaning, welding and machining. In order to solve the insufficiency of the driving capacity when the load of the ultrasonic driver changes, a high robustness LC matching design method is proposed based on the equivalent circuit modeling and the amplitude-frequency characteristic analysis of circuit transfer function. The transfer function of the input current including the matching capacitance and inductance is established by using the amplitude-frequency characteristics of the circuit transfer function. In order to simplify the transfer function, two new parameters as: impedance coefficient kz and frequency coefficient kf is introduced and a robust matching method based on uncertainty solving is proposed. The superiority of the proposed method compared with the existing matching method is proved by simulation and experiment. The experimental results show that the current fluctuation is less than 10% from light load to full load, which proves the reliability and robustness of our proposed method is higher than the existing matching method. It can ensure the amplitude stability of the ultrasonic transducer, and its performance is optimal than the existing general matching method.