A Quick Response Power Factor Detector for Nonlinear Loads

A fast power factor detector for nonlinear loads is proposed to overcome the drawback of conventional detectors, which can measure only the power factor of linear loads. The design of the proposed detector is based on the concept of additional characteristic of trigonometric function. It does not require any low-pass filter or integrator. Therefore, the transient response of the proposed detector is much faster than that of the conventional detectors. The theoretical response time of the proposed detector is less than one-fourth of a cycle. Because of its promising accuracy and rapid transient response, it can be used in many systems such as the control of power systems, and active power filters, to improve their transient performance. Theoretical analysis and experimental results are also detailed in this paper.

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Cooperative Control of Active Power Filters in Power Systems without Mutual Communication

Mathematical Problems in Engineering ◽

10.1155/2010/517184 ◽

2010 ◽

Vol 2010 ◽

pp. 1-13 ◽

Cited By ~ 6

Author(s):

Josef Tlustý ◽

Jiří Škramlík ◽

Jan Švec ◽

Viktor Valouch

Keyword(s):

Power Systems ◽

Power System ◽

Cooperative Control ◽

Harmonic Load ◽

Nonlinear Loads ◽

Power Circuit ◽

Active Power Filters ◽

Power Filters ◽

Node Voltage ◽

Mutual Communication

The procedure for calculating controller parameters of the APFs implemented into a multibus industrial power system for harmonic voltage mitigation is presented. The node-voltage-detection control strategy is applied and the basic controller parameters are found under the condition that the demanded THD factors at the buses where the APFs are placed will be obtained. A cooperative control of several APFs without mutual communication is proposed, simulated, and experimentally verified. By tuning the controller gains without considering the power circuit parameters, all APFs used tend to share harmonic load currents approximately equally regardless of the operation modes of the nonlinear loads in different parts of the power system.

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Proposing Wavelet-Based Low-Pass Filter and Input Filter to Improve Transient Response of Grid-Connected Photovoltaic Systems

Energies ◽

10.3390/en9080653 ◽

2016 ◽

Vol 9 (8) ◽

pp. 653

Author(s):

Bijan Rahmani ◽

Weixing Li

Keyword(s):

Transient Response ◽

Photovoltaic Systems ◽

Pass Filter ◽

Low Pass Filter ◽

Input Filter ◽

Low Pass

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Development of Shunt-Type Three-Phase Active Power Filter with Novel Adaptive Control for Wind Generators

The Scientific World JOURNAL ◽

10.1155/2015/963456 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Ming-Hung Chen

Keyword(s):

Power Factor ◽

Adaptive Filter ◽

Harmonic Distortion ◽

Active Power Filter ◽

Active Power ◽

Pass Filter ◽

Low Pass Filter ◽

Power Filter ◽

Wind Generators ◽

Low Pass

This paper proposes a new adaptive filter for wind generators that combines instantaneous reactive power compensation technology and current prediction controller, and therefore this system is characterized by low harmonic distortion, high power factor, and small DC-link voltage variations during load disturbances. The performance of the system was first simulated using MATLAB/Simulink, and the possibility of an adaptive digital low-pass filter eliminating current harmonics was confirmed in steady and transient states. Subsequently, a digital signal processor was used to implement an active power filter. The experimental results indicate, that for the rated operation of 2 kVA, the system has a total harmonic distortion of current less than 5.0% and a power factor of 1.0 on the utility side. Thus, the transient performance of the adaptive filter is superior to the traditional digital low-pass filter and is more economical because of its short computation time compared with other types of adaptive filters.

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A Step-by-Step Design for Low-Pass Input Filter of the Single-Stage Converter

Energies ◽

10.3390/en14237901 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7901

Author(s):

Qingqing He ◽

Lei Liu ◽

Mingyang Qiu ◽

Quanming Luo

Keyword(s):

Power Factor ◽

Power Factor Correction ◽

Design Method ◽

Single Stage ◽

Input Current ◽

Higher Harmonics ◽

Pass Filter ◽

Low Pass Filter ◽

Input Filter ◽

Low Pass

Active power factor correction converters are often introduced as the front stage of power electronic equipment to improve the power factor and eliminate higher harmonics. A Boost or Buck-Boost converter operating in discontinuous current mode is always adopted to achieve high power factor correction. In addition, the input current contains a large amount of higher harmonics, and a low-pass input filter is commonly adopted to filter it out. In this paper, a single-stage high-frequency AC/AC converter is taken as an example to demonstrate the design method of a passive low-pass filter. Firstly, the input side of the grid needs to meet the power factor and harmonic requirements. The preset parameters are set to a range to characterize the performance of the LC filter. The quantitative design method of input filter is proposed and summarized. Moreover, the sensitivity of the filter parameters is analyzed, providing a direction in practical applications. Preset parameters are all proved to conform to the preset range through PSIM simulation. Finally, a 130-W prototype is established to verify the correction of proposed design method. The power factor is around 0.935 and harmonic content in the input current is about 26.4%. All requirements can be satisfied.

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