Design of a Servo Drive with High-Precision Current Sampling Capability

This paper adopts a modular design approach to develop a low-cost low-voltage servo drive. For the multi-power supply issue, a power management system combining DC-DC conversion and LDO regulators is designed to improve power conversion efficiency and stability. A differential current sampling circuit is employed to acquire both DC bus current and motor phase currents, enhancing current measurement accuracy. A dual-loop control algorithm (speed-current) is specifically designed and debugged for PMSM control. Experimental results demonstrate that the proposed low-voltage servo drive exhibits fast response characteristics and excellent operational stability.