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The paper reviews research data of hybrid system of reactive power compensation for Metro electric power substations. Comparative compensation analysis has been made and control system for suggested device has been developed, besides mathematic simulation has been carried out as a result of which power factor of substation has been increased from 0.5 to 0.97–0.99.
This work presents the extended capabilities of a single-phase Pulse Width Modulation (PWM) rectifier to achieve a unity power factor (PF) in the Point of Common Coupling (PCC). It can act as a dynamic var compensator, fixed var compensator and Active Power Filter (APF). To accomplish such tasks a control scheme based in two cascaded loops is used. The outer loop regulates the dc bus voltage and provides...
A new dc-link voltage controller of a shunt active power filters is proposed in this paper. A fixed and regulated dc-link voltage is necessary to improve dynamic response of shunt active power filter. The dc-link voltage regulation is done by a sliding mode control method. Comparison made between the proposed controller and conventional PI regulator that used for dc-link voltage regulation. In this...
This paper deals with the power flow analysis and control strategy research of unified power quality conditioner (UPQC). A UPQC is a combination of shunt and series active power filter (APF), sharing a common dc link. It can compensate almost all power quality problems such as voltage harmonics, voltage unbalance, voltage flickers, voltage sags, voltage swells, current harmonics, current unbalance,...
This paper proposes a three-phase four wire current-controlled Voltage Source Inverter (CC-VSI) for both harmonic mitigation and PV energy extraction. For harmonic mitigation, the CC-VSI works as a grid current-controlling shunt active power filter. Then, the PV array is coupled to the DC bus of the CC-VSI. The MPPT controller employs the Fibonacci search method. The output of MPPT controller is a...
Active power filter is a reliable and effective technology for harmonic elimination and reactive power compensation. Based on the traditional control strategy for detecting load harmonic current, a new multiple-loop composite control strategy is proposed. The new control strategy has five control loops, which are used for calculating reference voltage signal of the inverter by detecting the load harmonic...
Harmonic voltage amplification, due to unintentional series or parallel resonance of power factor correction capacitors, is a significant issue in the industrial power system. Conventional active filters intended to compensate the harmonic current producing by nonlinear loads would not be an effective solution in this scenario, and the harmonic voltage may still be significant. This paper proposes...
To address power quality problems in industrial power systems, a new control scheme for three-phase active power filter is proposed. The control scheme includes two functional modules such as a current harmonic cancellation module and a reactive power compensation module. The current harmonic cancellation module is based on a multiple adaptive feed-forward cancellation algorithm for selective current...
As one of the most effective methods to inhibit electric power grid harmonics, the technology of Active Power Filter (APF) has been a key subject in the field of power quality control. Currently, research on APF mainly focuses on topology structure and control strategy. A novel topological structure of APF in alpha-beta coordinate is presented based on transformation of three phase static A-B-C coordinate...
The conventional PI controller used in active power filters (APF) requires precise linear mathematical models, which are difficult to obtain and may not give satisfactory performance under parameter variations, load disturbances, etc. In order to address this shortcoming, the novel fuzzy logic controller which is composed of PI controller and fuzzy controller is proposed in this paper. The combined...
Active Power Filter (APF) is useful device to compensate the harmonics which are caused by the nonlinear load, and its performance index mainly depends on the parameter design and structure of controller. In order to solve this problem, new Hamilton model of active power filter is introduced and the Energy Shaping Control Principle is used to design controller which corrects the output current waveform...
This paper presents the required harmonic power and rating issues of the active filter and power components. A design procedure is presented to select the DC bus capacitor that covers all modes of operation. The effect of the DC bus ripple on the compensation capacity is analyzed. A typical problem is included to illustrate the design approach followed by simulation results showing the static performance...
This paper presents a complete strategy for harmonics identification and neural control of a three-phase voltage inverter used for the power active filtering. Based on the use of neural techniques, this approach of compensation is done in two stages. The first stage extracts the harmonic currents with the diphase currents method by using Adaline neural networks. The second stage injects the harmonic...
The model and the normal control method of the cascaded H-bridge active power filter is described firstly in this paper. However, problems exist in the normal control. One of the main problems is the unbalance of DC capacitor voltages of the H-bridge units. In this paper, an improved method for DC capacitor voltages control of the cascaded H-bridge active power filter is presented. With slightly shifting...
This paper introduces a new adaptive notch filtering approach as a selective harmonic extraction technique. This method is capable of detecting a selective order of harmonics. This feature is useful where elimination of certain harmonics is of concern. Moreover, the proposed method can successfully detect and track the variations in the frequency and amplitude of the signal and extract the time-varying...
Three-level NPC inverter has been put into practical use for years especially in high voltage high power grid. This paper researches three-level active power filters(APF). In this paper the mathematical model in d-q coordinates is presented for 3-phase 3-wire APFs. The dead-beat control scheme is obtained by using the state equations. Canceling the delay of one sampling period and providing the predictive...
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 demanded THD factors at the buses where the APFs are placed will be obtained. A cooperative control of several APFs...
To real time detect the positive sequence of fundamental waveform is key technologies for power quality compensating mechanism. The three-phase positive sequence detecting method without phase lock loop (PLL) based on the dq0 coordinate transformation was put forward in this paper. To design control system of series voltage compensating mechanism with the method, the equipment can well achieve wave...
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