A speed control circuit based on phase-locked loop(PLL) is designed to achieve the constant speed operation, and a current-restricting circuit is designed to achieve the constant power operation.

• 设计了一种基于锁相环的速度闭环控制电路，进行电机的稳速控制，通过限流电路改变电机系统的特性，实现恒功率控制。