Split Dc Inverter Air Conditioner Outdoor Electrical Control System Design

Brushless DC motor (BLDCM) was widely used because of its excellent characteristics such as easy maneuverability, high-efficiency, low cost, well maintainability. In the field of air-conditioning manufacture industry, the variable velocity DC air-conditioner, which takes the concentrated winding brushless DC motor as its core technique for compressor, has become the focus of air-conditioning development.In this paper, brushless DC motor, the kernel of the compressor, was firstly introduced. Its numerical model was also established and the concentrated winding configuration was analyzed with the torque of the motor. According to the use requirement of compressor, the synch-open-loop startup and acceleration of BLDCM was realized by increasing frequency with voltage, and the signal of exchanging phase was generated by detecting the signal integrated from the back electromagnetic force.In terms of the functional requirement of air compressor outdoors, a high speed digital signal processor was chosen as the control core. The hard ware, which could perfectly drive and control the peripheral equipment of outdoor air compressor system and finish the information exchange with indoor system by serial communication of electrical wire, was also devised based on control circuit of dsPIC30F5015, systematic power supply circuit and protecting circuit, back electromagnetic force testing circuit and power electronic circuit used intelligent power module PS21865. In view of large torsional pulse value when the configuration of concentrated winding is adopted, the torsional pulses of brushless DC motor driven by rectangular current and sine wave current are analyzed, and the pulse torsion was minished with Space Vector PWM algorithm. Considering the phasic offset of Back Electromagnetic Force circuit, close-loop timing control for non-position sensor was realized with phase equalization. Based on detailed analysis of the work status for whole system, the principium design of the electro-control system software for the outdoor system of air-conditioner was conceived.At last, the control testing was carried out through a systematic prototype. And the testing result shows that the hardware and software of system works well and are with proper structural design.