Modeling and Analysis of Parallel Inverters Based on Droop Control

doi:10.11985/2016.05.003

Abstract

Abstract:

The droop control method has been widely used in the wireless paralleled inverters system. The coefficients selection of droop controller has a great influence on the stability and dynamic response of the inverters. Aimed at the inherent defects of the traditional droop control method, this paper introduces an orthogonal transformation reflecting system impedance characteristics and a derivative droop component, which makes the improved droop control break away the limits of system impedance characteristics and have the fast dynamic response. A small-signal model of parallel inverters based on droop control is proposed by using the time-varying phasor. Different from the traditional small-signal model with quasi-stationary assumption, the novel model takes into account the real-time adjustment of droop control to the inverter output voltage, which reflects the impact of droop coefficients on system stability more comprehensively. Under the condition of the known system parameters, the range of droop coefficients can be more accurately established by the stability analysis of the new model. Experimental results show the rationality of small-signal stability analysis and the proposed droop coefficients ensure the excellent stability and dynamic response of parallel inverters.

Key words: Droop control, parallel inverters, small-signal model, stability analys

CLC Number:

TM464

Lü Yi. Modeling and Analysis of Parallel Inverters Based on Droop Control[J]. Journal of Electrical Engineering, 2016, 11(5): 21-29.

Figures/Tables 12

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系统参数	表示符号	数值
系统阻抗/Ω	R + jX	0.02 + j0.06
输出电压幅值/V	E（≈V）	311
输出电压频率/(rad/s)	ω	100π
低通滤波时间常数	τ	0.016

下垂系数	优化数值
相角比例下垂系数k_p	4×10^-5
相角微分下垂系数k_pd	1×10^-6
幅值比例下垂系数k_q	4×10^-4
幅值微分下垂系数k_qd	1×10^-6