A New Method of Three-Phase Unbalanced Load Harmonic Current Detection

2014 ◽  
Vol 1070-1072 ◽  
pp. 726-730
Author(s):  
Hong Zheng ◽  
Yun Zhang ◽  
Jun Huang ◽  
Zhe Yu Wang
Keyword(s):  
Reactive Power ◽  
Detection Algorithm ◽  
Phase System ◽  
Instantaneous Reactive Power Theory ◽  
Three Phase ◽  
Unbalanced Load ◽  
Zero Sequence ◽  
New Type ◽  
Leakage Error ◽  
Improved Algorithm

The extensive usage of power electronic equipments makes harmonic problem increasingly serious. In unbalanced three-phase system, traditional p-q, d-q method ignores the zero sequence currents, resulting in zero sequence harmonic leakage error. This article is based on the basic principle of instantaneous reactive power theory, it proposes a new type of harmonic detection algorithm, this algorithm does not need phase-locked loop nor do a matrix transformation, and can effectively avoid the zero order harmonic leakage error caused by coordinate transformation.In the end, using Matlab/Simulink environment to build models of traditional algorithm and improved algorithm .Through comparison, the simulation result shows that the improved algorithm is more accurate and more effective than the traditional one.

Deduction of Coordinate Transform for Instantaneous Reactive Power Theory

2014 ◽  
Vol 641-642 ◽  
pp. 1219-1222
Author(s):  
Xue Song Zhou ◽  
Da Yan Wang ◽  
You Jie Ma
Keyword(s):  
Reactive Power ◽  
Detection Method ◽  
Three Dimension ◽  
Coordinate Systems ◽  
Power Theory ◽  
Instantaneous Reactive Power Theory ◽  
Three Phase ◽  
Instantaneous Reactive Power ◽  
Zero Sequence ◽  
Coordinate Transform

By means of building up a three-dimension coordinate system in vector space, the coordinate transform used in instantaneous reactive power theory (IRPT) proposed by H. Akagi is deduced and through spatial coordinate transform two equivalent three-dimension coordinate systems are obtained. After rigorous mathematical deduction the transformation factor for above-mentioned three-dimension coordinate systems is achieved, thus the coefficient deduction for IRPT is solved and the zero-sequence quantity expressing three-phase asymmetrical system is directly obtained. By use of the theory of rotating phasor, the basic principle of instantaneous spatial vector detection method based on IRPT is explained. The authors’ analysis is available for understanding and improvement of this harmonic current detection method.

Modeling and Simulation of Power Electronic Distribution Transformer Based on a Three Level Converter

2015 ◽  
Vol 785 ◽  
pp. 151-155 ◽  
Author(s):  
K.Y. Ahmed ◽  
N.Z. Yahaya ◽  
V.S. Asirvadam ◽  
Oladimeji Ibrahim
Keyword(s):  
Reactive Power ◽  
Minimum Size ◽  
Power Electronic ◽  
Distribution Transformer ◽  
Output Stage ◽  
Electronic Distribution ◽  
Three Phase ◽  
New Type ◽  
Power Electronics Converter ◽  
Level Converter

In this paper, a new type of power electronic distribution transformer (PET) has been introduced based on the power electronics converter on the primary and secondary sides of the transformer. This PET has three stages and the input stage has a three-level, three-phase rectifier. The middle stage has two three-level single-phase converters and a high-frequency transformer; and, the output stage is a three-phase, two-level inverter. This power electronic distribution transformer provides many advantages, such as power factor improvement, reactive power compensation, eliminating harmonics, and controlling and protecting itself (PET) with minimum size, compared to the traditional transformer. The MATLAB/Simulink was used to analyze and validate the power electronic distribution transformer.

The Control Technology of the Z-Source Three-Phase Four-Leg Inverter Based on Computer Simulation

2014 ◽  
Vol 981 ◽  
pp. 688-694
Author(s):  
Ming Su ◽  
Xue Yan Ma ◽  
Yan Sun
Keyword(s):  
Computer Simulation ◽  
Output Voltage ◽  
Control Method ◽  
Control Technology ◽  
Modulation Technique ◽  
Three Phase ◽  
Unbalanced Load ◽  
Zero Sequence ◽  
Current Flows

Z-source inverter can boost the voltage of the DC-side, allow the two switches of the same leg conducting at the same time and it has some other advantages. The zero-sequence current flows through the fourth leg of the three-phase four-leg inverter so the three-phase four-leg inverter can work with unbalanced load. This paper presents a Z-source three-phase four-leg inverter which combines a Z-source network with three-phase four-leg inverter. The circuit uses simple SPWM modulation technique and the fourth leg uses fully compensated control method. The inverter can maintain a symmetrical output voltage when the proposed scheme under the unbalanced load.

Research on Improved Power Harmonic Current Detection Methods

2012 ◽  
Vol 241-244 ◽  
pp. 1889-1895
Author(s):  
Jin Yu Wang ◽  
Zhi Hui Shen ◽  
Yu Long Zhou ◽  
Pei Jiang Zhang
Keyword(s):  
Coordinate Transformation ◽  
Reactive Power ◽  
Detection Algorithm ◽  
Detection Methods ◽  
Matlab Simulation ◽  
Harmonic Current ◽  
Two Phase ◽  
Three Phase ◽  
Filtering Effect ◽  
Current Detection

Although Active Power Filter can achieve good filtering effect and accurately compensate harmonic current, it dependents on the proposed current detection algorithm. The paper first discusses the method which is based on transient reactive power theory; the detection method is based on coordinate transformation. After the coordinate transformation is analyzed, the paper advances an harmonic method, this method can remove three-phase to two-phase and two-phase to three-phase coordinate transformation, and effectively reduce the computation, improve the detection speed. At last, the feasibility and validity of the new algorithm have been showed by MATLAB simulation

The Simulation Research of Harmonic and Reactive Current Detection

2013 ◽  
Vol 373-375 ◽  
pp. 992-995
Author(s):  
Jun Li Wan ◽  
Wen Jie Chen
Keyword(s):  
Real Time ◽  
Reactive Power ◽  
Active Power Filter ◽  
Active Power ◽  
Harmonic Detection ◽  
Power Theory ◽  
Instantaneous Reactive Power Theory ◽  
Power Filter ◽  
Three Phase ◽  
Reactive Current

This paper arrives at a method of harmonic and reactive current real-time detection applied on active power filter based on the three-phase circuit instantaneous reactive power theory. With Matlab simulation software, a research on simulation of harmonic detection means is carried out, and an analysis of the simulation result is presented. The result indicates: the harmonic detection means based on instantaneous reactive power theory can detect harmonic and reactive component in three-phase current precisely and real-time, to supply reliable harmonic and reactive current for harmonic restraint and reactive power compensation. It could provide reliable indicator parameters for research and development of active power filter.

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