A parameter design method of LC filter circuit for closed‐loop dynamic power supply system based on linear power amplifier

• Published in: IET power electronics 2024-11, Vol.17 (14), p.1852-1866
• Main Authors: Yang, Feixiang, Wang, Xueqing, Luo, Jin, Duan, Qianwen, Ning, Zongqi, Mao, Yao
• Format: Article
• Language: English
• Subjects: DC motors; DC–DC power convertors; drives; LC circuits; low‐pass filters; motor drives; PI control; power amplifiers; power supply circuits; switching circuits
• ISSN: 1755-4535; 1755-4543
• DOI: 10.1049/pel2.12743

The linear power amplifier (LPA) suffers from low power supply utilization in the DC power supply mode, leading to reduced output efficiency. This paper constructs an efficient power supply mode based on closed‐loop dynamic power supply system (CLDPSs). The CLDPSs can generate a pair of bipolar dynamic power supplies based on a predetermined signal to provide power to LPA, which can maintain a small voltage drop between the power supply and the output of LPA, thereby improving the power supply utilization of LPA. In addition, the study also focuses on the conflicting relationship between the output ripple and the dynamic performance of the CLDPSs, for which a new parametric design of the LC filter circuit is proposed, aiming to achieve a balance between these two aspects. Finally, a voice coil motor driving platform is constructed for experimental testing. The results demonstrate that the output ripple and dynamic performance of the CLDPSs can be balanced. In comparison to the DC power supply mode, the CLDPSs power supply mode can enhance the efficiency of LPA by 2 times while the driving accuracy of voice coil motor is basically unchanged. In order to improve the efficiency of linear power amplifiers, a bipolar closed‐loop dynamic power supply system based on synchronous buck circuits is proposed as a replacement for the traditional DC power supply. This system can significantly improve the utilization rate of the power supply. At the same time, a design for the parameters of the LC filter circuit is proposed to balance the contradiction between the output accuracy and dynamic performance of the closed‐loop dynamic power supply system, which can improve the efficiency and ensure the accuracy of the linear power amplifier simultaneously.