Fundamental current detection method considering zero sequence for three-phase four-wire system

The article considers a hybrid power quality conditioner (HQPC) for 3-phase 4-wire systems with a distributed modular structure. Some conditioner modules provide compensation for the component currents and voltages that form the negative and zero sequence systems. The open structure of the HQPC, consisting of independent modules, allows compensating for distortions of currents and voltages of the 3-phase network caused by the nonlinear nature and asymmetry of single-phase loads. The compensation characteristics of the proposed conditioner were researched using a model developed in the MatLab environment. The simulation showed that the proposed conditioner can ensure normalization of power quality in 3-phase 4-wire system at various modes of network operation.

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A New Method of Harmonic Current Detection and Control Strategy of Compensating Current

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.588-589.986 ◽

2012 ◽

Vol 588-589 ◽

pp. 986-989

Author(s):

Xiang Cheng ◽

Tie Lin Zheng ◽

Gui Hong Feng

Keyword(s):

Detection Method ◽

Current Control ◽

Phase Voltage ◽

Power Filter ◽

Three Phase ◽

Reactive Current ◽

Asymmetric Power ◽

And Control ◽

Current Detection ◽

Control Accuracy

This paper puts forward and realizes a detection method, which can extract harmonic and reactive current accurately when the network exists nonideal and asymmetric power grid voltages. From the view of vector analysis, through the d-q coordinates[1,2] project transformation of the three-phase voltage and current vectors, the harmonic and reactive current extraction is realized. The compensation current adopts forecast current control, obtaining a better compensation characteristic and control accuracy .From the experimental results of 5 kVA active power filter（APF）and 150 kVA mixing filters, the feasibility and the correctness of the proposed method are proved.

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A Reactive and Harmonic Current Detection Method of Three-Phase Asymmetric System

2010 International Conference on Computational and Information Sciences ◽

10.1109/iccis.2010.310 ◽

2010 ◽

Cited By ~ 2

Author(s):

Hu Yong-jun ◽

Fan Li-li ◽

Hu Ya-jing

Keyword(s):

Detection Method ◽

Harmonic Current ◽

Asymmetric System ◽

Three Phase ◽

Current Detection

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Deduction of Coordinate Transform for Instantaneous Reactive Power Theory

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.641-642.1219 ◽

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.

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Unbalanced and Reactive Currents Compensation in Three-Phase Four-Wire Sinusoidal Power Systems

Applied Sciences ◽

10.3390/app10051764 ◽

2020 ◽

Vol 10 (5) ◽

pp. 1764 ◽

Cited By ~ 1

Author(s):

Rafael Montoya-Mira ◽

Pedro A. Blasco ◽

José M. Diez ◽

Rafael Montoya ◽

Miguel J. Reig

Keyword(s):

Power Systems ◽

Positive Sequence ◽

Electrical System ◽

System A ◽

Compensation Methods ◽

Three Phase ◽

Zero Sequence ◽

Unbalanced Loads ◽

Wire System

In an unbalanced linear three-phase electrical system, there are inefficient powers that increase the apparent power supplied by the network, line losses, machine malfunctions, etc. These inefficiencies are mainly due to the use of unbalanced loads. Unlike a three-wire unbalanced system, a four-wire system has zero sequence currents that circulate through the neutral wire and can be compensated by means of compensation equipment, which prevents it from being delivered by the network. To design a compensator that works with unbalanced voltages, it is necessary to consider the interactions between it and the other compensators used to compensate for negative-sequence currents and positive-sequence reactive currents. In this paper, through passive compensation, a new method is proposed to develop the zero sequence current compensation equipment. The method does not require iteration algorithms and is valid for unbalanced voltages. In addition, the interactions between all compensators are analyzed, and the necessary modifications in the calculations are proposed to obtain a total compensation. To facilitate the application of the method and demonstrate its validity, a case study is developed from a three-phase linear four-wire system with unbalanced voltages and loads. The results obtained are compared with other compensation methods that also use passive elements.

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A Precise Current Detection Method Using a Single Shunt and FET Rds(on) of a Low-Voltage Three-Phase Inverter

Electronics ◽

10.3390/electronics11010009 ◽

2021 ◽

Vol 11 (1) ◽

pp. 9

Author(s):

Jae-Yeob Hwang ◽

Ji-Hwan Park ◽

Ji-Ho Choi ◽

Jun-Ik Uhm ◽

Geun-Ho Lee ◽

...

Keyword(s):

Kalman Filter ◽

Detection Method ◽

Low Voltage ◽

Harmonic Distortion ◽

Torque Ripple ◽

Current Sensor ◽

Phase Inverter ◽

Three Phase ◽

Current Detection ◽

Three Phase Inverter

In this study, a low-voltage three-phase inverter was used alongside a shunt resistor to measure the current. However, it is known that this type of inverter and shunt resistor system has a region where the measurement of current is impossible due to structural limitations. As a result, many studies have focused on this region through the use of additional algorithms. Most studies measured current by forcibly adjusting the PWM duty in order to measure the current at the region where it could not be sensed. However, unfortunately, the total harmonic distortion (THD) increases in the current due to PWM adjustment. This causes an increase in torque ripple and inverter control instability. Therefore, in this paper, current was measured using the Rds(on) value between the drain source resistor when MOSFET was turned on and the Kalman filter in a low-voltage three-phase inverter with a single shunt. Additionally, the value was verified via comparison with the values achieved when a Hall-type current sensor and single shunt were used. As a result, this study confirmed that the inverter with a single shunt performs the same as a Hall-type sensor at the region where current cannot be detected.

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