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11.37%, and 7th times harmonic distortion rate reduced to 0.83% from 7.82%.
As the paper can see that the 3rd, 5th and 7th harmonic content is greatly
reduced. Therefore, the control strategy put forward in this article has favorable
compensation effect on the voltage drop and harmonic voltage in steady-state.
6Conluon
The paper proposes a new-type control strategy to make DVR inverter unit to
compensate the low-order harmonic waves caused by nonlinear factors, like dead
time and nonlinear load, and the effect of digital control on system performance,
while ensures the dynamic response characteristic of DVR inverter unit. The
thesis analyzes the discretization method of RP controller in current literature,
designs in a detailed way the parameters of voltage outer-loop fundamental PR
controller and current inner loop third, fifth and seventh harmonic PR controller
in discrete filter. In the process of analyzing the performance of control system
and designing parameters, the paper introduces one time-delay, and therefore
achieves the control performance and harmonic compensation effect closer to
actual DVR. The harmonic PR controller can effectively restrain the influence
of the specific harmonic current in load current on DVR output voltage. The
fundamental PR controller can not only realize the zero steady -error, but also
restrain the effect of load current on output. The experiment of DVR prototype
proves the e
ciency of the control strategy in this paper.
References
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