ABSTRACT:
This
paper focuses on designing a disturbance observer-based control (DOBC) system
for PMSM drives. The cascade structure of the discrete-time PI-PI control
system with tracking anti-windup scheme has been designed for both loops. In
this study, high order disturbance observer (HODO) based control is used to
improve the speed tracking performance of the control system for the PMSM
prototyping kit regardless of the disturbance and unmodelled dynamics. The
motion equation was modified in the HODO in which torque losses due to the drug
resulting from the time-varying flux, hysteresis, and friction have been taken
into account to estimate the total disturbance. The HODO does not require the
derivatives of the disturbance to be zero, like in the traditional ones. It
demonstrates its ability to estimate along with a load torque the high order
disturbances caused by a cogging torque and a high-frequency electromagnetic noise
in the PMSM system. In the real-time experiments, the proposed algorithm with
HODO achieves less speed errors and faster response comparing with the baseline
controller. The performances with proposed and baseline control have been
evaluated under mechanical speed and load torque variation cases. The experimental
results have proved the feasibility of the proposed control scheme. The
proposed disturbance observer-based control system was implemented with a
Lucas-Nuelle 300 W PMSM prototyping kit.
KEYWORDS:
1. Disturbance
observer based control
2. High-order
disturbance observer
3. PI
controller
4. PMSM
Cascaded PI-PI
Load torque observer
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Figure 1. Proposed Dobc Based Control Method Structure.
EXPECTED SIMULATION RESULTS:
Figure 2. Experimental Results Of The Proposed
Hodo Based Pi With Novel Anti-Windup Scheme For Case 1. (A) Mechanical Speed
Response Of Pmsm; (B) Mechanical Speed Error; (C) Estimated Load Torque Disturbance.
Figure 3. Dq-Axis Currents Of The Proposed Hodo
Based Pi With Novel Anti-Windup Scheme For Case 1. (A)Ids And Its Desired Value
Idsd; (B) Iqs And Its Desired Value Iqsd
Figure 4. Dq-Axis Voltages Under Proposed Hodo
Based Pi With Novel Anti-Windup Scheme For Case 1. (A) Control Input On Q-Axis
Vqs; (B) Control Input On D-Axis Vds.
Figure 5. Experimental Results Of The Proposed
Hodo Based Pi With Novel Anti-Windup Scheme For Case 2. (A) Mechanical Speed
Response Of Pmsm; (B) Mechanical Speed Error; (C) Estimated Load Torque Disturbance.
Figure 6. Dq-Axis Currents Of The Proposed Hodo
Based Pi With Novel Anti-Windup Scheme For Case 2. (A) Ids And Its Desired
Value Idsd; (B) Iqs And Its Desired Value Iqsd.
Figure 7. Dq-Axis Voltages Under The Proposed Hodo
Based Pi With Novel Anti-Windup Scheme For Case 2. (A) Control Input On Q-Axis
Vqs; (B) Control Input On D-Axis Vds.
Figure 8. Experimental Results Of The Baseline
Control For Case 1. (A) Mechanical Speed Response Of Pmsm; (B) Mechanical Speed
Error.
Figure 9. Dq-Axis Currents Of Baseline Control For
Case 1. (A) Ids And Its Desired Value Idsd; (B) Iqs And Its Desired Value Iqsd.
Figure 10. Dq-Axis Voltages Of The Baseline Control
For Case 1. (A) Control Input On Q-Axis Vqs; (B) Control Input On D-Axis Vds.
Figure 11. Experimental Results Of The Baseline
Control For Case 2. (A) Mechanical Speed Response Of Pmsm; (B) Mechanical Speed
Error.
CONCLUSION:
In
this paper, disturbance observer based control for the PMSM prototyping kit is
proposed. The cascade structure of discrete-time PI-PI control system equipped
with tracking anti-windup scheme has been utilized for both loops. As the total
disturbance estimation with HODO is based on the accurate prediction of the
mechanical speed, the detailed motion equation of the PMSM has been derived.
The motion equation in the proposed HODO includes terms associated with torque
losses due to drag resulting from time-varying flux, friction, and hysteresis.
It has demonstrated its ability to improve the speed tracking performance under
the external disturbance and unmodelled dynamics associated with a cogging
torque and a high-frequency electromagnetic noise in the PMSM system. The estimated
total disturbance is compensated in the speed controller. A zero steady-state
errors have been achieved in the real time experiment. The mechanical speed
errors were minimized in both operation scenarios. The performances of the
proposed and baseline control algorithms have been evaluated under mechanical
speed and load torque variations. The performance of the novel control system
has shown better robustness to the external disturbances.
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[2]
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[3]
B. Sarsembayev, K. Suleimenov, B. Mirzagalikova, and T. D. Do, ``SDRE- based
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