The space solar array simulator is a crucial part of satellite power systems, simulating the output characteristics of solar arrays under various load conditions during ground tests. However, existing power supplies exhibit limited fast-tracking performance. To address this challenge, this paper presents a fast-tracking power supply based on optimized D-CAP+ control and enhancement-mode GaN transistor. The proposed control scheme is tailored for high-voltage, low-current applications, simplifying ripple injection through a divided-frequency technique that reduces phase distortion and shortens the control loop cycle. Simulation results show that the optimized control tracks a 50 V step signal in 15.3μs (65.4kHz), with a steady-state voltage error of 0.12%, ripple blow 300 mV, and minimal phase shift for a 50 kHz sine wave. A power supply prototype with a voltage rating of 100 V/50 V, power rating of 250 W, and power density of 43.03 W/in³ was built. Experimental results demonstrate a 20.4% improvement in dynamic response and good steady-state performance, verifying the effectiveness of optimized D-CAP+ control in improving tracking bandwidth.
