Research On Sensorless Brushless DC Motor-driver For Pumps

The brushless DC motor is attached to a kind of permanent magnet synchronousmotor.The rotor permanent magnet structure, making the motor structure becomes moresimple, smaller and more efficient. Moreover, the use of electronic commutation, instead ofmechanical commutation makes the brushless DC motor have the speed performance ofDC motor. Therefore, the brushless DC motor have been widely used in many fields. Inorder to further simplify the structure and cost of motor, sensorless control has becomeincreasingly important. In this paper, the research focus on the existing low-cost marketdiscussing the control of brushless DC motor and proposing own methods.This article will discuss from the most basic structure and working principle ofbrushless DC motor, and expound the essence of electronic commutation instead ofmechanical commutation. Based on this, establishing the mathematical model ofbrushless DC motor, so as to further discussing the control of sensorless brushless DCmotor.As clarifying the position sensorless brushless DC motor control method, we willdiscuss two EMF zero-crossing detection methods in the existing low-cost market: Samplecalculation of EMF zero crossing and Comparator detects the zero crossing signal. AsDicussing the results of the two detection methods in different speed range, and circuitdesign, we will ues TMS320F28035as master chip.According to the applicationcharacterized in their own methods will both blend, making the motor can be detected backEMF zero-crossing signal in a wide speed range.After discussing the position detection method of position sensorless brushless DCmotor, in this paper, we will explain three-step start and position sensorless detection amore detailed discussion.Finally, according to the subject of background requirements, design currentclosed-loop control system based on the motor mathematical model. By selecting theappropriate proportional integral parameters, to build a stable operating system, therebyimproving system efficiency and stability.