ABSTRACT:
How to calculate the reference voltage vector is an
important issue in space vector modulation direct torque control (SVM-DTC) of
permanent magnet synchronous motor (PMSM). The effect of zero vector on
electromagnetic torque during all speed range is analyzed on the basis of the
relation between voltage vector and torque current component. And the analysis
shows that in conventional DTC system of PMSM available voltage vector is only
six which is the mainly cause of high ripple of torque. A robust SVM- DTC
method of PMSM is designed in which the reference voltage vector is calculated
with the flux position, error of torque and flux. The method is simple to
implement and insensitive to motor parameters error. First order filter
cascaded with high pass filter (HPF) is adopted to estimate stator flux
accurately. The experimental results are carried out and show that the improved
SVM-DTC has the advantage of simplicity, robustness and improved performance.
KEYWORDS:
1.
PMSM
2.
Direct torque control
3.
Space vector modulation
4.
Torque ripple
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.1 Block diagram of improved SVM-DTC
system
EXPECTED SIMULATION RESULTS:
a) Experimental waveforms of
conventional DTC
b) Experimental waveforms of proposed
SVM-DTC
CONCLUSION:
Available
voltage vector has only six which mainly causes high ripple of torque in
conventional DTC. To maintain robustness and simplicity of conventional DTC
system, a simple method of calculating amplitude and angle of the voltage
vector is adopted in SVM-DTC. It requires only the torque and flux errors. The
simulation and experimental results show that the proposed SVM-DTC scheme has excellent
steady-state performance while retaining the merits of the quick dynamic
responses, simplicity and robustness as in conventional DTC.
REFERENCES:
[1]
Bin Wang, Yue Wang, Zhaoan Wang. Direct torque control of permanent magnet
synchronous motor drives using space vector modulation [J]. Electric machines
and control, 2010, 14(6):45-50.
[2]
Yong-chang Zhang, Jian-guo Zhu, Wei Xu , You-guang Guo. A Simple Method to
Reduce Torque Ripple in Direct Torque-Controlled Permanent-Magnet Synchronous
Motor by Using Vectors With Variable Amplitude and Angle[J]. IEEE Transactions
on Industrial Electronics, 2011, 58(7): 2848-2859.
[3]
Gilbert Foo, M. F. Rahman. A novel speed sensorless direct torque and flux
controlled interior permanent magnet synchronous motor drive [C]. Power
Electronics Specialists Conference, Rhodes, Greece, 2008: 50- 56.
[4]
Huaqiang Zhang, Xinsheng Wang, Pengfei Wei, etal. Study on direct torque
control algorithm based on space vector modulation [J]. Electric Machines and
control, 2012, 16(6):13-17.
[5]
Jing Yuan; Xigeng Ma; Jiannan Liu. Simulation research of induction motor based
on SVM-DTC with three-level inverter [J]. Electronics Information and Emergency
Communication, China, 5th.2015, 410- 413.
