Power conversion efficiency in DC-to-RF MOS-FET high power inverter operating at 2.5 MHz

A description is presented of how to increase the power conversion efficiency in a full-bridged DC-to-RF MOS-FET power inverter consisting of four MOS-FET arrays, each array consisting of six MOS-FETs to enhance the output power to 1 kW at a frequency of 2.5 MHz. Although the voltage-fed type has a total DC-to-RF power conversion efficiency of over 60% in the supplied DC voltage range of 80 to 180 V, the current-fed type has a total DC-to-RF power conversion efficiency of over 80% in the same DC voltage range. Data were obtained at the output powers ranging from 250 to more than 1000 W when the square-wave output voltage was fed to the resistive load whose characteristic impedance was 50 Omega when the load was used as an RF heater.<
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