Design of digital DC speed adjusting system based on DSC

HUANG Liangbing， CHEN Fu
(20th Research Institute, China Electronic Technology Group Corporation, Xian 710068, China）

Abstract: The analogue DC speed adjusting system has the defects of complex circuitry, bad universality and susceptible to device performance and atmosphere temperature, etc.. In order to eliminate the defects, a digital DC speed adjusting system based on digital signal controller(DSC) was proposed. The dsPIC30F4011 from Microchip Technology Inc. which is oriented to motor control was used as the controller. A strategy of double closedloop which includes the currentloop as the innerloop and the speedloop as the outerloop was taken into the system. The digital PI adjusting of the loops and the generating of the pulse width modulation(PWM) control signal were all done by the DSC software. The engineering practice result shows that the system has the profits of high accuracy, small overshoot, good disturbance immunity and high reliability etc..
Key words: DC speed adjusting system; digital signal controller(DSC); currentloop; speedloop