Highly Efficient IPT Transmitter Circuit Based on a Novel Enhanced Class B Amplifier for Consumer Applications

Designing an efficient Inductive Power Transfer (IPT) system involves significant challenges. On the transmitter side, it is essential to provide the transmitter coil with an alternating current (AC) operating within the kHz-MHz frequency range, which is generally generated by inverters linked to an intermediate direct current (DC) bus. While methods such as Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS) can effectively minimize losses, they frequently lead to increased design complexity and voltage distortion. This paper introduces a compact and highly efficient transmitter circuit, with dimensions of 40 x 60 mm, utilizing an enhanced Class B AC-AC amplifier. This amplifier incorporates an operational amplifier with adjustable gain to deliver a trapezoidal waveform to the gates of the connected MOSFETs. The specific waveform effectively reduces crossover distortion and enhances the overall efficiency of the converter. Experimental results indicate that the efficiency of the proposed circuit surpasses 98%, which is suitable for powering small to medium load levels.