PMSM Speed Sensor less Direct Torque Control Based On EKF Best Electrical Engineering Projects

ABSTRACT
System with mechanical speed sensor has lower reliability and higher cost. Traditional direct torque control method has disadvantages of big ripples on current and flux linkage and torque. To solve these problems, the Extended Kalman Filter is established to estimate both stator flux linkage and rotor speed. Therefore, speed sensorless direct torque control for surface permanent magnet synchronous motor is realized. Simulation results have shown that the advantage of direct torque control method such as rapid torque response is maintained, at the same time, the system based on EKF is robust to motor parameters and load disturbance. The dynamic and static performances are dramatically improved.

KEYWORDS
1. Direct torque control
2. Permanent magnet
3. Synchronous motor (PMSM)
4. Extended kalman filter (EKF)
5. Stator flux linkage observation
6. Speed sensorless control
SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:


Figure 1. Schematic diagram of speed sensorless DTC control for SPMSM based on EKF
EXPECTED SIMULATION RESULTS:


(a) DTC-based on EKF method (b) Traditional DTC method
Figure 2. Stator flux linkage wave

(a) DTC-based on EKF method (b) Traditional DTC method
Figure 3. Electromagnet torque wave

(a) DTC-based on EKF method (b) Traditional DTC method
Figure 4. Rotor speed wave


(a) DTC-based on EKF method (b) Traditional DTC method
Figure 5. A phase current wave

Figure 6. Estimated speed and real speed waves
(a) Real rotor angle wave (b) Estimated rotor angle wave

Figure 7. Rotor angle wave

CONCLUSION:
Speed sensorless DTC control based on EKF for SPMSM is proposed. For a relatively accurate SPMSM model, flux linkage and rotor speed and rotor position can be estimated more precisely by EKF algorithm. Ripples on torque and stator flux are reduced. The motor start problems are solved as EKF do not need accurate initial rotor position information to achieve observer stability convergence. DTC control for PMSM based on EKF has just begun. Many places are imperfect and need for further study.
REFERENCES:
[1] L.Zhong, M.F.Rahman, W.Y. Hu , K.W.Lim, “Analysis of direct torque control in permanent magnet synchronous motor drives,” IEEE Trans. On Power Electronics, 1997, 13(5), pp:528-536.
[2] Jun Hu, Bin Wu. “New integration algorithms for estimating motor flux over a wide speed range,” IEEE Trans. on Power Electronics, 1998, 13(5),pp:969-977.
[3] Cenwei Shi, Jianqi Qiu, Mengjia Jin, “Study on the performance of different direct torque control methods for permanent magnet synchronous machines,” Proceeding of the Csee, 2005, 25(16),pp:141- 146.
[4] Limei Wang, Yanping Gao. “Direct torque control for permanent magnet synchronous motor based on space voltage vector pulse width modulation,” Journal of Shenyang University of Technology, 2007,29(6), pp:613-617.
[5] Zhiwu Huang, Yi Li, Xiaohong Nian, “Simulation of direct torque control based on modified integrator,” Computer Simulation, 2007,24(02),pp:149-152.

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