Research on Unbalanced Voltage Support of Flexible Current Control Based Three-Phase Four-Wire Converter in Low Voltage Station Area

2021 ◽  
Author(s):  
Weixiang Huang ◽  
Haojie Chen ◽  
Li Yu ◽  
Yu Feng ◽  
Yangjun Zhou ◽  
...  
Keyword(s):  
Low Voltage ◽  
Current Control ◽  
Three Phase ◽  
Unbalanced Voltage ◽  
Voltage Support

Part 1: Decomposition of the Load’s Current in Three-phase Four-wire Systems Supplied with Asymmetrical Sinusoidal Voltage Following Currents’ Physical Components Theory

2020 ◽  
Vol 11 ◽  
pp. 34-42
Author(s):  
Zbigniew SOLJAN ◽  
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Supply Voltage ◽  
Sinusoidal Voltage ◽  
Power Equation ◽  
Three Phase ◽  
Unbalanced Voltage ◽  
Wire System ◽  
Phase Asymmetry ◽  
Physical Components

Electricity receivers in low-voltage networks are mainly single-phase loads, which, when grouped within a given consumer, create a three-phase load. Such a replacement three-phase load works in a four-wire system. Besides, under real conditions, the supply voltage has some amplitude and phase asymmetry. Voltage unbalances, load's imbalances are issues that not simultaneously included in the power equation in four-wire systems. This article eliminates the limitations of electrical engineering in this area by deriving the power equation for three-phase loads supplied with unbalanced voltage.

Inductor Saturation Compensation in Three-Phase Three-Wire Voltage-Source Converters via Inverse System Dynamics-I

2020 ◽  
Author(s):  
Ziya Özkan ◽  
Ahmet Masum Hava
Keyword(s):  
Dynamic Model ◽  
Dynamic Performance ◽  
Current Control ◽  
Inverse System ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Two Phase ◽  
Inverse Dynamic ◽  
Three Phase ◽  
Steady State Current

In three-phase three-wire (3P3W) voltage-source converter (VSC) systems, utilization of filter inductors with deep saturation characteristics is often advantageous due to the improved size, cost, and efficiency. However, with the use of conventional synchronous frame current control (CSCC) methods, the inductor saturation results in significant dynamic performance loss and poor steady-state current waveform quality. This paper proposes an inverse dynamic model based compensation (IDMBC) method to overcome these performance issues. Accordingly, a review of inductor saturation and core materials is performed, and the motivation on the use of saturable inductors is clarified. Then, two-phase exact modelling of the 3P3W VSC control system is obtained and the drawbacks of CSCC have been demonstrated analytically. Based on the exact modelling, the inverse system dynamic model of the nonlinear system is obtained and employed such that the nonlinear plant is converted to a fictitious linear inductor system for linear current regulators to perform satisfactorily.

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