Fullbridged MOS-FET DC-to-RF power inverter for use with high-frequency high-power ultrasonic transducer

A full-bridge MOSFET DC-to-RF power inverter consisting of four branches, each branch consisting of three MOSFETs connected in parallel to enhance the power handling capability, was built for driving a high frequency, high power ultrasonic transducer with an output power of 600 W operating at 1 MHz. When the power inverter was connected to the ultrasonic transducer through an output transformer with a primary-to-secondary winding ratio of 2 to 1, the load impedance looking into the load from the inverter was 3.5 ohms at 1 MHz, and was high enough to drive the load with high power conversion efficiency, i.e., over 80%.<
>