High-Efficiency Broadband Electroacoustic Energy Conversion Using Non-Foster-Inspired Circuit and Adaptively Switched Capacitor

To achieve the maximum power transfer between the power amplifier (PA) and the electroacoustic transducer, this article proposes a broadband complex impedance matching network using the non-Foster-inspired circuit and adaptively switched capacitor. The proposed method has the ability to simultaneously optimize the power utilization and power factor (PF) of the PA over a wide bandwidth, in contrast to the singular objective feature of existing methods. First, with the adaptively switched capacitor, the variable resistance of the transducer is adjusted to match the optimum output resistance of PA. Subsequently, the non-Foster-inspired circuit is used to compensate for the variable reactance of the transducer. In this way, the equivalent impedance seen by the PA is optimized to achieve high-efficiency energy conversion. To apply the switched capacitor to scenarios where the operating frequency varies in a broadband range, a dynamic reference signal calculation method is proposed to adaptively adjust the optimal equivalent capacitance. Simulation and experimental results show that the proposed control method can quickly respond to changes in operating frequency and transducer impedance. With the proposed network, the PA can provide maximum active power output to the electroacoustic transducer while maintaining the PF in unity over a wideband frequency range.