Research Of Brushless DC Motor Control System In Automotive Air Conditioning Based On DSP

Automotive air conditioning is an important auxiliary device inautomotive system,with the automobile industry towards to the green andenergy efficient development trend,the traditional brush DC motor orasynchronous motor drive method will be unable to meet the requirements ofindustrial development. Brushless DC motor is an electronically commutatedDC motor, It’s not only retains the good speed performance of the brush DCmotor and also has the advantage of no commutation spark, small size, lownoise, high efficiency and so on, so this makes brushless DC motor havebroad application prospects in automotive air conditioning system. Traditionalcontrol of the brushless DC motor need to get the motor commutation signalsthrough position sensor, but in the automotive air conditioning system of bignoise and big vibration and other harsh environment, the use of positionsensor is limited, so it’sneed to use sensorless control technology. For thereason, this paper studied a sensorless brushless DC motor control system forthe automotive air-conditioning system motor drive.Firstly, this paper introduced the definition and basic structure of thebrushless DC motor, use the Three-phase and star connection brushless DCmotor as an example to analysis of its working principle and driving method,Focus on the research of back-EMF(back electromotive force) zero crossingdetection method of the sensorless brushless DC motor control technologyand the research of brushless DC motor starting methods, introduced thebrushless DC motor PWM control strategy, and proposed the necessity andfeasibility of double-loop PI control in the system.And then, based on the expected achieve performance, this paper usingTMS320LF2407A as the controller to designed the hardware circuit of thesystem, Elaborated the hardware circuit design method of power circuit, DSPminimum system circuit, motor drive circuit, back-EMF zero crossing signal detection circuit and the current sampling circuit, Gives the modular programdesign ideas and flowcharts of the brushless DC motor control system.Finally, this paper doing some performance tests and experimentalresearch of the sensorless brushless DC motor control system, Experimentalresults show that the design method of this paper is feasible and effective, It’scertainly has some Engineering practical significance.