Refrigerator refrigeration compressor controller based on dsPIC30F4012 (part 1)

Refrigerator refrigeration compressor controller based on dsPIC30F4012 (part 1)




Abstract: Based on dsPIC30F4012 design a refrigeration compressor for refrigerators brushless DC motor control system. The drive motor through the three-l-frequency step-up method starts, when you run to the satisfaction of self-synchronization speed, single-chip by detecting the motor terminal voltage to obtain the rotor commutation point, and through the PID control algorithm to improve system robustness. After testing, the system has good stability and controllability, both to reduce costs, but also flexible control with high practical value.



Keywords: brushless DC motor (BLDC); digital signal processor (DSP); pulse width modulation (PWM); PID algorithm; dsPIC30F4012



1 Introduction

Household refrigerator compressor drive motors generally use the single-phase asynchronous motor. In order to improve overall performance of refrigerators, energy-saving noise reduction, improve the efficiency of the refrigerator cooling system is required on the compressor motor speed control. Brushless DC motor BLDC (brushless DC motor) AC motor only has simple structure, reliable operation, convenient maintenance advantages, but also has high efficiency DC motor and speed advantages of good performance, therefore, used here for designing a dsPIC30F4012 Refrigeration Compressor brushless DC motor control system.



2 System Control Program

The system is designed with speed, current, position, three closed-loop control scheme, available to a good control performance.

As the motor starts back EMF zero or very small, three-up-step-up method using the motor to start, this process is mainly achieved by software, by giving more frequently accused of providing motor drive signals, while continuing to improve drive signal duty cycle until the motor reaches a certain speed and then turned to white-synchronous operation mode. Self-synchronization run-time. MCU by detecting the back EMF zero-crossing point to determine motor position, and then position signal according to rewrite OVDCON (control register) value, power inverter pwm_on modulation, namely, the power devices in the first 60 ° turn to PWM modulation, after the 60 ° to maintain Hengtong 22 conduction mode. The high utilization rate of turn-winding ways, electrical to contribute to the largest stable of the best, and PWM modulation control of a simple, non-controlled dead zone, can effectively inhibit the commutation torque ripple, significantly improve the motor performance.



To learn more about power inverter, please visite http://www.szpowerinverter.com/ and http://www.bestekltd.com/, or mail to sale38@0102.cn.