Flying-Capacitor Linear Amplifier with Capacitor Voltage Balancing Control for Efficient and Low Harmonic Power Conversion

In general power converters, high efficiency power conversion is realized owing to the switching operation of semiconductor power devices. However, the switching operation causes some issues such as harmonic distortion and electromagnetic interferences. As a solution to these issues, this paper presents the flying-capacitor linear amplifier (FCLA), which realizes high-efficiency power conversion without the switching operation. A voltage balancing control of flying-capacitors using individual gate circuits is proposed in this paper to extend the number of the series-connected MOSFETs and achieve higher efficiency. The operation principle of the individual gate circuit and a control methodology of the voltage balance for the flying-capacitors are clarified in a simulation. It is confirmed that the FCLA with 30-series MOSFETs operates without any additional voltage balancing circuit and achieves more than 95 % efficiency even as a linear amplifier. Finally, a practical design and implementation of the proposed gate circuits are shown.