A Novel Mathematical Method for Calculating the LCL-Type Matching of Ultrasonic Transducer for Liquefaction Treatment

This article presents a novel mathematical method for calculating the inductor–capacitor–inductor (LCL)-type matching of ultrasonic transducer used in liquefaction treatment. When the ultrasonic transducer is used for liquefaction treatment, the load impedance changes drastically. With traditional inductor–capacitor (LC) matching circuits, the driving voltage of the transducer may become very high due to the sudden increase of the load impedance, especially at the startup. This ultrahigh voltage may cause damage to the transducer and generator. The LCL -type matching circuit calculated with the proposed mathematical method can keep the transducer voltage relatively stable no matter how the load changes. Since the variation of the load will lead to a slight change in the resonant frequency and the frequency tracking speed is limited by the software of the generator, the transducer may temporarily lose locking, which also causes the transducer voltage to fluctuate. This voltage fluctuation can be minimized by the LCL matching circuit provided in this article, and then, the LCL matching is quiet suitable for ultrasonic liquefaction treatment.