An Optimal PR Control Strategy with Load Current Observer for a Three-Phase Voltage Source Inverter

Energies

Xiaobo Dou¹  Kang Yang¹  Xiangjun Quan¹  Qinran Hu¹  Zaijun Wu¹  Bo Zhao²  Peng Li²  Shizhan Zhang¹  Yang Jiao¹ 

[1] Department of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China; E-Mails:;State Grid Zhejiang Electric Power Research Institute, Hangzhou 310014, China; E-Mails:

关键词: multiple PR regulators;    load current observer (LCO);    voltage control;    three-phase inverter;   

DOI  :  10.3390/en8087542

来源: mdpi

【 摘 要 】

Inverter voltage control is an important task in the operation of a DC/AC microgrid system. To improve the inverter voltage control dynamics, traditional approaches attempt to measure and feedforward the load current, which, however, needs remote measurement with communications in a microgrid system with distributed loads. In this paper, a load current observer (LCO) based control strategy, which does not need remote measurement, is proposed for sinusoidal signals tracking control of a three-phase inverter of the microgrid. With LCO, the load current is estimated precisely, acting as the feedforward of the dual-loop control, which can effectively enlarge the stability margin of the control system and improve the dynamic response to load disturbance. Furthermore, multiple PR regulators are applied in this strategy conducted in a stationary αβ frame to suppress the transient fluctuations and the total harmonic distortion (THD) of the output voltage and achieve faster transient performance compared with traditional dual-loop control in a rotating dq0 frame under instantaneous change of various types of load (i.e., balanced load, unbalanced load, and nonlinear load). The parameters of multiple PR regulators are analyzed and selected through the root locus method and the stability of the whole control system is evaluated and analyzed. Finally, the validity of the proposed approach is verified through simulations and a three-phase prototype test system with a TMS320F28335 DSP.

【 授权许可】

CC BY   
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