A High Speed Coprocessor Design for Sensorless PMSM Control

Permanent Magnet Synchronous Motors (PMSMs) are widely used in industries, and high-speed PMSMs are becoming common. Digital control systems are frequently used for PMSM control, which introduce control delays. These delays may reduce the bandwidth of the control loop and even cause the current regulator to lose stability. Complicated algorithms are often proposed to alleviate control delays. This paper attempts to address this problem from another perspective. A high-speed coprocessor working with a RISC-V processor core is proposed; both of them are implemented on an FPGA. The coprocessor not only implements the basic functions of FOC and SVPWM and integrates current-loop and speed-loop control, but more critically, it also implements a sliding mode observer for rotor position estimation for sensorless control of PMSMs. Simulations and experiments are conducted to verify the effectiveness of the proposed architecture, and a computational speedup of more than 20 times is achieved.