A High-Precision Power Amplifier with Weighted Multi-Objective Current-Loop Tuning method for High-Precision Linear Propulsion

High-precision linear propulsion systems require power amplifiers (PAs) that simultaneously provide ultra-low current distortion and high-bandwidth current tracking. However, in conventional switched PAs, dead-time effect and current zero-crossing distortion severely degrade current linearity, while existing controller tuning approaches often fail to explicitly balance closed-loop peaking, robustness, and bandwidth in digitally implemented high-frequency systems. To address these challenges, this paper proposes a high-precision switched PA featuring two coordinated innovations at both the power stage and control stage. First, an auxiliary-current commutation mechanism is introduced into the switched PA so that the MOSFET current is forced to reverse in every switching period. As a result, dead-time effect and current zero-crossing distortion are eliminated at the source, while ZVS-ON is achieved and the equivalent switching frequency is increased. Second, to fully exploit the improved power stage, a weighted multi-objective controller parameter tuning method is proposed. The method establishes a discrete-time current-loop model consistent with the practical implementation and jointly constrains the closed-loop peak, phase margin, sensitivity, complementary sensitivity, and bandwidth, so as to achieve a balanced tradeoff between tracking accuracy, dynamic response, and robustness. Experimental results verify an equivalent switching frequency of 1 MHz, a minimum current THD of 0.03%, a closed-loop tracking error within 0.34dB below 10kHz, and a maximum achievable bandwidth of 14kHz. These results demonstrate that the proposed PA provides a practical solution for precision-oriented linear propulsion applications requiring both ultra-low distortion and high dynamic current tracking.