High Performance DC Chopper Speed and Current Control of Universal Motors Using a Microcontroller

This paper introduces a high performance DC chopper speed and current control system for universal motors. Differing from existing TRIAC and DC chopper speed control schemes, the new system adds the inner current control to improve dynamic response, and the motor starts up with closed speed and current control loops. Complete control schemes have been developed and implemented in a low cost Renesas R8C/25 16-bit microcontroller. Through a series of dynamometer tests, it has been shown that the proposed DC chopper control of the universal motor with both speed and current control has good speed regulation and fast response. It also has low acoustic noise, less current harmonics, low motor temperature, more torque and high motor efficiency. The experimental results demonstrate that the developed universal motor control has great potential and practical significance for industrial applications.