Three-phase Active Power Research Articles

Adaptive Second-Order Sliding Mode Fuzzy Control Based on Linear Feedback Strategy for Three-Phase Active Power Filter

The increasing use of nonlinear loads entails serious electrical energy quality problems in power grids. Active power filter could lead to significant improvement in harmonic compensation performance. In this paper, an adaptive second-order sliding mode fuzzy control based on linear feedback strategy for a three-phase active power filter is proposed to eliminate harmonics. This scheme is constituted by adaptive controller, second-order sliding mode controller, fuzzy controller, and linear feedback controller. The linear feedback controller can compensate the system’s nonlinearities and make the new system have a linear behavior between the input and output. Moreover, the second-order sliding mode controller could transfer the discontinuities in the controller and reduce system chattering. Simulation results illustrate the proposed controller has better performance compared with fuzzy control and adaptive sliding mode fuzzy control.

Улучшение синхронизации параллельного активного силового фильтра с питающей сетью

The paper reviews the features of the synchronization system for three-phase shunt active power filters. It suggests an improved more stable design of a synchronization system with. The synchronization system has been improved by introducing bandpass filters in order to filter the input signals of a conventional phase-locked loop synchronization system. The design of the second-order infinite impulse response bandpass filter has been elaborated. The simulation of the three-phase shunt active power filter with the proposed synchronization system was carried out. The simulation results were verified by the laboratory prototype of a three-phase active power filter.

Analysis, design and simulation of three-phase active power filter with series capacitor topology for current harmonic compensation

The proposed system consists of an LC passive filter connected in series with three-phase active power filter. The passive filter is tuned to 13th order harmonic frequency. Major portion of harmonic current generated by nonlinear load is absorbs by passive filter, and active filter is used to improve filtering performance of the system by providing compensation for host of other higher order harmonics. Requirement of dc-link voltage of the active filter is less in the presented scheme as compared to that of standard voltage source active power filter without any other passive filtering component. This resulted in significant reduction in cost and power rating of active power filter. Analysis and design of various components of active filter are presented. Simulation analysis is carried out using instantaneous active-reactive power (P-Q) theory. Simulation results verify circuit configuration and filtering performance of the proposed topology. This system can be an attractive solution for effective harmonic filtering.

Dynamic global proportional integral derivative sliding mode control using radial basis function neural compensator for three-phase active power filter

An adaptive dynamic special global sliding mode controller that is based on proportional integral derivative (PID) sliding surface using radial basis function (RBF) neural network (NN) for a three- phase active power filter (APF) was presented in this paper. To overcome the problems associated with the schemes of the conventional sliding mode control, a global PID sliding manifold is introduced to realize the whole process of robustness and inhibition of the steady state error, accelerating the system response meanwhile. In addition, the nested dynamic sliding mode controller can reduce the influence of chattering that may lead to malfunction of the insulated gate bipolar transistor (IGBT) caused by sign function in the control law, achieving a better property. Moreover, owing to the parameter uncertainties and the external disturbances, a RBF neural estimator is added to eliminate the chattering phenomenon that further optimizes the performance of the system. Eventually, simulation studies in the MATLAB/SimPower Systems Toolbox verify the outstanding performance of the designed RBFNN dynamic global PID sliding mode controller in three different conditions, and some comparisons are made at the same time to demonstrate the excellent properties of the raised control method.

Finite Control Set Model Predictive Control for a Three-Phase Shunt Active Power Filter with a Kalman Filter-Based Estimation

In this paper, the finite control set model predictive control is combined with the vector operation technique to be applied in the control of a three-phase active power filter. Typically, in the finite control set technique applied to three-phase power converters, eight different vectors are considered in order to obtain the optimum control signal by minimizing a cost function. On the other hand, the vector operation technique is based on dividing the grid voltage period into six different regions. The main advantage of combining both techniques is that for each region the number of possible voltage vectors to be considered can be reduced to a half, thus reducing the computational load employed by the control algorithm. Besides, in each region, only two phase-legs are switching at high frequency while the remaining phase-leg is maintained to a constant dc-voltage value during this interval. Accordingly, a reduction of the switching losses is obtained. Unlike the typical model predictive control methods which make use of the discrete differential equations of the converter, this method considers a Kalman filter in order to improve the behavior of the closed-loop system in noisy environments. Selected experimental results are exposed in order the demonstrate the validity of the control proposal.

Dynamic Optimal AC Line Current Regulation Method for Three-Phase Active Power Conditioners

The main feature of the three-phase back-to-back active power conditioner (APC) is to improve the power quality of the microgrid. During the large power variation transient, the severe voltage surge/sag on the dc-link of the APC may cause its malfunction. Therefore, the dynamic optimal ac line current regulation (DOCR) with flexible dc-link voltage slope (FDVS) is proposed in this paper. The proposed DOCR can determine the accurate input current reference value to regulate the dc-link voltage under the large power variation condition. On the other hand, the proposed FDVS can further mitigate the dc-link voltage variation during the large power variation transient. The mathematical equations of the proposed control strategy are derived thoroughly. Furthermore, procedures to determine the dc-link capacitance with the proposed DOCR are developed. Finally, the experimental results obtained from a 5-kVA back-to-back APC verify the feasibility and the performance of the proposed line current regulation strategies.

三相電力用アクティブフィルタの3次高調波電流補償に伴う直流コンデンサ電圧脈動の抑制法

三相電力用アクティブフィルタの3次高調波電流補償に伴う直流コンデンサ電圧脈動の抑制法

Robust adaptive fuzzy control of a three-phase active power filter based on feedback linearization

In this paper, a robust adaptive fuzzy control system using feedback linearization is proposed for a three-phase active power filter (APF). The APF system is divided into two separate loops: the current dynamic inner loop and the DC voltage dynamic outer loop. Adaptive fuzzy tracking control using feedback linearization is employed for the current dynamic inner loop to overcome the drawbacks of the conventional method. The proposed controller can ensure proper tracking of the reference current and impose desired dynamic behavior, giving robustness and insensitivity to parameter variations. Adaptive fuzzy proportional-integral control is applied to the DC voltage dynamics outer loop to improve the dynamic response and reduce the error of the stable state. Simulation results demonstrate the high performance of the proposed adaptive fuzzy control strategies.

A Backstepping Neural Global Sliding Mode Control Using Fuzzy Approximator for Three-Phase Active Power Filter

In this paper, a backstepping global sliding mode fuzzy control based on neural network together with a proportional integral derivative (PID) sliding mode manifold is proposed for a three-phase active power filter (APF). This system consists of a backstepping PID global sliding mode controller, a fuzzy uncertainty approximator and a neural estimator. The design process of Lyapunov function and the controller can be systematic and structured through the reverse design by backstepping control. A global sliding mode controller is introduced to obtain overall robustness, speeding up the system response. On the issues of the conventional proportional derivative sliding mode surface, the integral item is added to suppress the steady state error and enhance the robustness. Besides, it is beneficial to estimate the unknown dynamic characteristics of the APF system via RBF neural network. Furthermore, the fuzzy controller utilized to approach to the switching function can reduce the influence of chattering which may lead to insulated gate bipolar transistor malfunction of the actual active power filter, achieving a better property. Finally, simulation studies with MATLAB/SimPower systems toolbox demonstrate that the designed backstepping neural PID global sliding mode fuzzy controller can obtain expected properties in three different conditions, and some comparisons are made to verify the superior performance of the raised control method.

LMF-Based Control Algorithm for Single Stage Three-Phase Grid Integrated Solar PV System

This paper proposes the use of a least mean fourth (LMF)-based algorithm for single-stage three-phase grid-integrated solar photovoltaic (SPV) system. It consists of an SPV array, voltage source converter (VSC), three-phase grid, and linear/nonlinear loads. This system has an SPV array coupled with a VSC to provide three-phase active power and also acts as a static compensator for the reactive power compensation. It also conforms to an IEEE-519 standard on harmonics by improving the quality of power in the three-phase distribution network. Therefore, this system serves to provide harmonics alleviation, load balancing, power factor correction and regulating the terminal voltage at the point of common coupling. In order to increase the efficiency and maximum power to be extracted from the SPV array at varying environmental conditions, a single-stage system is used along with perturb and observe method of maximum power point tracking (MPPT) integrated with the LMF-based control technique. The proposed system is modeled and simulated using MATLAB/Simulink with available simpower system toolbox and the behaviour of the system under different loads and environmental conditions are verified experimentally on a developed system in the laboratory.

Dynamic Control and Analysis of DC-Capacitor Voltage Fluctuations in Three-Phase Active Power Filters

This paper proposes a new control method of three-phase active power filters for reducing the dc capacitor voltage fluctuations in transient load change. The proposed control method introduces a new $\boldsymbol{k}$ -step compensator, which maintains the mean active power flowing into the dc capacitor at zero every $\boldsymbol{1/(k-1)}$ ac line period. Therefore, the compensator can suppress the transient voltage fluctuations across the dc capacitor even when a quick load change occurs. This paper theoretically reveals the relationship between the step number $\boldsymbol{k}$ and the reduction effect of the dc voltage fluctuations. The experimental setup introducing the proposed seven-step compensator exhibits a good suppression effect of the dc voltage fluctuations and makes it possible to reduce the required capacitance value of the dc capacitor by a factor of seven.

T-S fuzzy model based adaptive fuzzy current tracking control of three-phase active power filter

This paper proposed an adaptive fuzzy state feedback controller for a three-phase active power filter (APF) based on a Takagi-Sugeno (T-S) fuzzy model. The T-S fuzzy model is based on the APF dynamic model in the dq frame, which ensures that the current control dynamic and DC capacitor voltage dynamic become decoupled. By using the parallel distributed compensation (PDC), local linear state feedback controller could be designed for each T-S fuzzy sub-model. To deal with the parametric uncertainties and external disturbances, a parameter estimation scheme for tuning the parameters of T-S fuzzy model is designed and the parameters are adjusted online by the adaptive law derived from the Lyapunov stability analysis. Simulation studies demonstrate that the proposed control method exhibit excellent performance in both steady state and transient operation during balanced and unbalanced load, and source voltage.

Reduced-rating Hybrid Active Power Filter Comprising Zero-sequence Transformer and Three-phase Three-wire Active Power Filter for Three-phase Four-wire Distribution System

A three-phase four-wire active power filter is proposed in this article that consists of a three-phase three-wire active power filter, zero-sequence transformer, and single-phase active power filter. The reference current for tracking the desired source current is based on the neural network (constraint anti-Hebbian rule algorithm). The three-phase three-wire active power filter compensates current harmonics and reactive power requirement of the non-linear load. A zero-sequence transformer and single-phase active power filter are used to mitigate the neutral current. The proposed hybrid scheme (three-phase four-wire active power filter) significantly reduces the volt–ampere rating of the active power filter and improves the performance under different utility voltage conditions. The simulation of the proposed three-phase four-wire active active power filter is carried out for different voltage conditions. Further, the MATLAB-simulated (The MathWorks, Natick, Massachusetts, USA) response of the three-phase four-wire active active power filter has been validated on a prototype of the three-phase four-wire active-active power filter. The experimental result obtained from the prototype verifies the effectiveness and viability of the proposed scheme.

A Power Monitoring System of Machine Tool

This paper completes a design of power monitoring system of machine tool based on MSP430F149 microcontroller. This system is mainly divided into four modules: the electric energy information input and processing module, electric energy metering operation processing module, Single-Chip Microcomputer system internal data processing module, and PC memory module, respectively. The voltage transformer and current transformer collect voltage signal and current signal respectively, which were inputted deferentially to the ATT7022A voltage channel and current channel, to achieve electric energy information input and processing. The special measure chip ATT7022A measures the three-phase active power, reactive power, apparent power, active energy and reactive energy to meter and operate electric energy. MCU system processing module communicates with ATT7022A chip via the SPI bus interface by using the 16 bit MSP430F149 microcontroller. The establishment of database model and database table using the relatively practical method of entity-relationship achieves PC internal data memory module. In addition, the fabrication of PCB circuit board and software writing are also introduced in detail in this paper.

Fast discrimination of stable power swing with synchronous generator loss of excitation

Fast and accurate discrimination between stable power swing (SPS) and synchronous generator loss of excitation (LOE) has been a great concern for power engineers. Since there is no unbalance during SPS condition, detecting this phenomenon is still a challenge. LOE detection methods are prone to interpret an SPS as a LOE event. Over the last decade, several techniques have been developed for LOE protection that most of them are based on the impedance trajectory as it enters into the protective zone. Such methods may not be able to discriminate between SPS and LOE. Therefore, assigning a time delay is usually utilised to overcome the possible maloperation of the LOE relay. However, merely providing the intentional time delay to avoid maloperation in this condition is not a perfect solution. This study presents a fast detection approach for this condition. The combined proposed method is based on the derivatives of the machine's external variables (i.e. output reactive power and terminal voltage) and the variation of the fast Fourier transform coefficient of the three-phase active power available at the location of the relay. The main advantage of this method is its speed, security and sensitivity to distinguish between SPS and LOE.

Analysis and Application of Repetitive Control Scheme for Three-Phase Active Power Filter with Frequency Adaptive Capability

Active power filter (APF) has been proved as a flexible solution for compensating the harmonic distortion caused by nonlinear loads in power distribution power systems. Digital repetitive control can achieve zero steady-state error tracking of any periodic signal while the sampling points within one repetitive cycle must be a known integer. However, the compensation performance of the APF would be degradation when the grid frequency varies. In this paper, an improved repetitive control scheme with frequency adaptive capability is presented to track any periodic signal with variable grid frequency, where the variable delay items caused by time-varying grid frequency are approximated with Pade approximants. Additionally, the stability criterion of proposed repetitive control scheme is given. A three-phase shunt APF experimental platform with proposed repetitive control scheme is built in our laboratory. Simulation and experimental results demonstrate the effectiveness of the proposed repetitive control scheme.

Study of three-phase active power filter operation using non-sinusoidal voltage

Study of three-phase active power filter operation using non-sinusoidal voltage

Experimental Verification of Quasi Z-Source Inverter Based Hybrid Series Active Power Filter for Interconnection of PV into the Utility Grid

This paper proposes a Photovoltaic/Battery interfaced Quasi Z-source inverter based three-phase four-wire Hybrid Series Active Power Filter (HSAPF)to compensate the voltage and current related power quality problem in small distributed power system. The HSAPF consists of shunt passive filter and series active filterconsuming a battery. The shunt active filter mitigates the current harmonics generated by a nonlinear load. The series active filter mitigates the voltage sag/swell and load voltage harmonics, which consumes the power from Photovoltaic (PV) array with quasi Zsource inverter (qZSI). A new controller of qZSI based HSAPF uses two control schemes to boost the PV/Battery output voltage and achieve maximum power point tracking PV array. The simulation and experimental results are presented to validate the performance of proposed qZSI based HSAPF.

Dynamic Surface Adaptive Fuzzy Control of Three-Phase Active Power Filter

The main objective of this paper is to design a dynamic surface adaptive fuzzy controller for a three-phase active power filter (APF). In order to deal with the nonlinearity of the APF, a fuzzy strategy combining an adaptive backstepping method is proposed where fuzzy controller is mainly responsible for the elimination of nonlinearities. Moreover, by adopting the dynamic surface method, the number of input variables of the fuzzy system in modeling could be reduced; therefore, the controller and design parameters can be implemented without complex calculation. The Lyapunov stability of closed-loop system with the fuzzy control, sliding control, and dynamic surface control could be assured. The simulation results prove that the dynamic surface adaptive fuzzy method has excellent performance in stability, robustness, adaptability, and total harmonic distortion (THD), which is confirmed to suppress harmonics effectively.

Renewable Energy Resources based DC-DC Power Converter for Micro Grid Power Quality Analysis

The power generation based micro-grid system connecting several small alternative power sources and also an addition to the maingrid one particular site. It can mentioned solar cells, wind turbines, micro-turbines (natural gas), fuel cells and storage batteries and also connected to the low voltage distribution network through power electronics converters. In this paper, proposed a three-phase Active Power Conditioner to improve power quality in microgrids based on renewable energy. Active Power Conditioner (APC) acts as an interface between renewable energy sources and the AC bus of micro-grid. Also, it can be proved important alternative to compensate current and voltage disturbances in power distribution systems. The novel control strategy used offer the possibility to inject electrical energy from the different renewable sources and another hand to improve the power quality in the same microgrid. The multilevel inverter connected in between the micro and main grid for power quality analysis, such as harmonic compensation, power factor correction, THD (total harmonic distortion), voltage and current balancing. The proposed topology have been implemented and results obtained by using MATLAB/SIMULINK.