Brushless DC Motor Controlled Systerm Of Four-Switch Three-Phase

Recent year,the Brushless DC Motor controller with low cost application,low power, high properties has been developed widely.In this paper,the simplification and optimization of this kind convers with minimized power switches are discussed.Based on theory of the Brushless DC Motor,analyse the topology structure of main circuit on the view of low coss.In this paper,the best choice is using four-switch three-phase converter.Two faults of four-switch three-phase converter are pointed out based on the principle of operation.One is asymmetric voltage vetor of four-switch three-phase converter. The other is the current aberration of no-controlled phase for the Back EMF.The electromagnetic torque of Brushless DC Motor when the current is anomaly.In this paper, The Current Hysteresis Band PWM control method is adopted for the two problems.It's theory is controlling the current directly.And the controlled phases are modeled independently to make that the current is like to the ideal wave.To low the cost of the controller,the Back EMF method is adopted to control the Brushless DC Motor.And the Back EMF rotor position detedting method is analysed.In the end,a control systerm is seted up using the dsPIC30F3011 which is produced for motor control.The result of experiment indicate that this systerm is feasible.