An Improved Current-Limiting
Strategy for Shunt
Active Power Filter (SAPF)
Using Particle Swarm
Optimization (PSO)
ABSTRACT:
The
current-limiting strategy for shunt active power filter (SAPF) will be
activated automatically, when the compensation-capacity need exceeds the rated
capacity. However, the traditional current-limiting strategy cannot realize the
comprehensive protection with optimum objectives. The paper firstly reveals the
essential of the current-limiting demands for the comprehensive protection of
SAPF, namely the limiting control objects: 1) the root mean square (RMS) of the
compensation current (mainly for the overheat protection of the IGBT and
inductor); 2) the instantaneous wave of compensation current (mainly for the
accurate current control and IGBT Icnom specification) and 3) the instantaneous
wave of PWM-VSC modulation voltage (for the need of liner close-loop control). Secondly,
the paper proposes an improved current-limiting scheme based on particle swarm
optimization (PSO) to achieve the two optimization targets: 1) the minimization
THD for the grid-side current; 2) the maximization utilization ratio for the capacity
of the SAPF. The main advantage lies on the optimum limiting ratios of each
harmonic order are calculated in real time respectively to achieve the flexible
and liner limiting control. Finally, simulation and experiment verify the
effectiveness of the proposed strategy.
KEYWORDS:
1.
Shunt active power filter
2.
Current-limiting demands
3.
Current-limiting strategy
4.
Particle swarm optimization
SOFTWARE:MATLAB/SIMULINK
BLOCK DIAGRAM:
Figure. 1. System mechanism diagram of
SAPF.
EXPECTED SIMULATION RESULTS:
1) Traditional
current-limiting control
Figure.
5. Simulation results of traditional current-limiting strategy.
(a):
Modulation voltage without current limitation, (c)(e):Load current and
spectrum
analysis, (b): Modulation voltage with traditional current limitation,
(d)(f):Grid-side
current Is, output compensation current Ic and spectrum
analysis
of Is.
2) Optimal current-limiting control using PSO
Figure. 6. Simulation results of the
proposed current-limiting strategy.
(a)(c)(e)(g): Simulation waves with the
optimum-capacity control strategy,
(b)(d)(f)(h): Simulation waves under the
optimum-THD control strategy.
CONCLUSION:
An improved current-limiting strategy
based on PSO is proposed to optimize the utilization rate of SAPF or the THD of
grid-side current. This strategy takes advantages of the two traditional
methods: equal-proportion current-limiting control and truncated
current-limiting control. Simulation results prove: the proposed
current-limiting scheme can reduce the THD of grid-side current and improve the
utilization rate of SAPF effectively, and no extra undesired harmonic will be
injected into the power system. Future work will focus on further experiment
validation for the effectiveness of the proposed method, especially dynamic performance.
REFERENCES:
[1] Sheng Xu, “An Improved
Current-limiting Control Strategy for Shunt Active Power Filter,” in IEEE 8th
International Power Electronics and Motion ControlConference, 2016, pp.
1306-1311.
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“Design and implementation of the parallelable active power filter,” in Annual
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“Repetitive-based control for selective harmonic compensation in active power
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1018-1024, Oct. 2004.
[4] Y.Tang, P.C.Loh, P.Wang, F.H.Choo,
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Electronics, vol. 59, no. 3, pp. 1443-1452, Mar. 2012.
[5] L. Asiminoaei, C. Lascu, F.
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With Dual Parallel Topology,” IEEE Transactions on Industrial Electronics, vol.
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