外文翻譯--無(wú)位置傳感器無(wú)刷直流電機(jī)的dsp控制系統(tǒng)（英文）

1、DSP Control System of Brushless DC Motor without Position SensorHuang Qingxin, Liang Hui Department of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, ChinaAbstract This paper designs a kind of varia

2、ble speedcontrol system of a brushless DC motor (BLDCM) without arotor position-sensor. Based on intelligent power module and DSP, this system uses the back electromotive force (Back-EMF)method to implement the position-

3、sensorless control for brushless DC motor. The system is highly integrated with flexible control and strong reliability. Experimental results indicate that this system has a high performance Keywords Brushless DC motor,

4、Position-sensorlesscontrol, Back-EMF, DSPI. INTRODUCTIONIn the past decades, with the development of motorcontrol, power electronics and microelectronics tech- nologies, BLDCM has become a new type of motor. The most imp

5、ortant feature of it is that the mechanical commutation configuration constituted by commutators and brushes is replaced by electrical commutationcircuitry. It solves the drawbacks caused by mechanical commutation and ma

6、intains the virtues of using a DC motor in varying velocity field, so it is applied widely on home appliance field, where DC variable frequency air-conditioner represents the air-conditioner using advanced technology and

7、 brushless DC motor has wentinto compressor field, making it more efficiency in energy consumption. In the transportation field, BLDCM has abright and wide future in the field of electric motor andfull electric ship. The

8、 rotor position signal ofBLDCM is usual provided by position sensor. But the existence of position sensor makes the configuration more complex, influences thereliance of motor operation and increases the cost of the moto

9、r. Nevertheless, in some specialized fields, it is not convenient to use position sensor, such as if there are high temperature, frozen and erosion materials, it defines the application of BLDCM. In this paper, the rotor

10、 position is detected via detecting the three phase terminal voltages. This kind of method don't use position sensor, reducedthe system cost and the volume of the motor, especially improved the characteristics of the

11、 system. Going with the development DSP, it is the trend to solve the increasing computation command in motor control system using high performance digital signalprocessor. In the meanwhile, intelligent power module with

12、 high integrated ratio is introduced in the paper, it tremendously improves the level of blocking about homeappliances. Considering the varying speed command of BLDCM, this paper proposes a variable frequency variable sp

13、eed system based on DSP and IPM. It makesthe whole control system's configuration compact,flexible to control and possess extensive practicality.II. SYSTEM HARDARE STRUCTUREA. Main circuitFig.1 is the main circuit di

14、agram of the system, mainly including three parts, such as rectifier, filtering and inverting circuits. Signal-phase bridge rectifier module is employed as the rectifier circuit, making the configuration with high reliab

15、ility and simple. while the inverter circuit employs IPM(PS21255) module, the IGBT drive circuit and protecting circuit are integrated inthe module, increased the reliability of the system and shortened the developing pe

16、riod. PS2 1255 is the newest DIP-IPM product manu- factured by Mitsubishi corporation, designed for home appliances and pint-sized transducers. Based on the IPM, the Dual Inline Package power module has the features of m

17、ore cost-effective, miniaturization, high reliable performance and easy to use. This IPM module employs the high speed low conducting voltage IGBT devices, simultaneously, the drive circuit is close to the IGBT chip, bro

18、ught the virtues of short drive time delay, high-speed switching and low power loss. IPM also possesses specialcircuits, such as high speed over current protection and excellent over temperature protection function. Inad

19、dition, because of optimized gate drive and theintegration of IGBT, the system has proper composition, no external drive circuit, small volume and excellent EMI elimination capability.Fig. 1. Main circuitB. DSP control c

20、ircuitThe control circuits of this system are composed by DSP and its peripheral circuits, Back-EMF zero-crossing detection circuit, speed command and display circuits. DSP is a newly produced motor digital control chip

21、by TI corporation, comparing with the former chips, the instruction cycle time is shorter. Moreintegrated peripheral parts, bigger chip internal storage and quicker analog to digital conversion speed are also provided, s

22、o it is more suitable to be used in high speed371R L0J { Va +{VnFig.4. Equivalent circuit of motor phase AFrom Fig4, the following voltage equations about BLDCM can be expressed asdt Vi =Ria+L dt+aV 1Vb = Rib+ L db + Eb

23、+ V, (2) dtdi Vf = Ri6+L dt +E, + V, (3) dt(3Because the motor adopts 1200 conducting mode,only two phases are energized at a time, so the current in the two phases has the same amplitude and oppositedirection, while in

24、another phase, the current is zero, the same with the total of three phase currents. Adding the upper three equations, we can getV, +Vb++V, =E +Eb+Ec +3V; (4)From Fig3, Ea+Eb+ Ec= 0 can be obtained at theinstant when eac

25、h phase Back-EMF crosses zero.Therefore, at the zero-crossing point of Back-EMF:1 Vn 3(Va + Vb + V) (5)From Fig4, when some phase winding current is zero,its phase Back-EMF is, for example phase A,a Va V;, when Va=V , th

26、en a =0, therefore, viadetecting phase terminal voltages, the neutral point voltage can be attained. When the terminal voltage is equal with the neutral voltage, the Back-EMF zero- crossing point of the phase can be dict

27、ated.B. Back-EMF detection circuitFig5 is the circuit principle diagram of A-phase Back-EMF zero-crossing detection point. Terminalvoltage Va attained from resistor array is transferred toVa +15Vfilter, rectangular wave

28、can be attained from comparingthe filtered signal V1 with V“, as shown in the Fig5,consequently, signal CAPI is got from the above rectangular wave through optoisolation and Schmidtrectifier circuit. Then it is transferr

29、ed to the capture port of DSP, the up and down edges are the instants the Back-EMF crossing zero. Vb, and V, are the othertwo-phase signals, generated by the same principle as Va .Because of employing PWM mode, the termi

30、nal voltage always contains high frequency modulatingsignals. This effects the normal operation of comparator, so filter is necessary for filtering the terminal voltagesignal. In Fig5, the parameter design of the filter

31、is very important, because it dictates whether the final attained rectangular signal can reflect the rotor position correctly and accurately, so you should pay special attention to it.First, you should guarantee the phas

32、e shift of the filter is minimal. The filtering circuit employed in this system makes the phase shift tremendously small shown in Fig5, so it has light influence on the detected signal. Second, because of the error cause

33、d by the elements, when you choose the elements R or C, you should guarantee that the differences whether resistances or reluctances among thethree phases are tremendously little, or else it may cause the phase shift ang

34、le inconsistently among the three phasefilters, and harmful influence to the operationcharacteristics of the motor.IV. SOFTWARE DESIGN OF THE CONTROL SYSTEMA. Softwareflow chartFig6 is the system software flow chart, the

35、 whole control system software is composed by the main program and the interrupt service subsystem, while the main program is composed by system initialize program, motorstart program. The A/D conversion to the speed com

36、mandis finished in the main program. Capture interrupt subprogram and timer compare interrupt service subprogram are the main composed parts of the interrupt service subprogram. The main function of capture interrupt is

37、to get three-phase Back-EMF zero-crossing instants and read the time interval between twice capture, so to calculate timer internal corresponding to the 30°angle. While the compare interrupt of the timer is used+15V