A comparative analysis of DFPI correctors and different techniques to regulate a shunt active power filter

The fitting of an active power filter (APF) to mitigate the effects of a diode or thyristor bridge-rectifier is predicated on the assumption that the rating of the filter is reasonable (i.e. small) compared with the rating of the existing bridge rectifier or of a replacement active rectifier. The ratings of both shunt and series APFs are analysed in a variety of operating conditions. Ratings are assessed through peak voltage and mean current as appropriate for junction semiconductor devices. Rms ratings are also given because of their familiarity. The series APF, appropriate for the compensation of harmonic voltage sources, is of a generally higher rating than the shunt APF, appropriate for harmonic current sources. The use of a shunt APF where a series APF is appropriate results in poor device utilisation. The semiconductor ratings of an APF can be reduced by using hybrid schemes. Removing large-amplitude, low-order current harmonics with harmonic traps is effective for the shunt APF. Reducing peak voltages by attenuating high-frequency components is effective with the series APF. Arranging rectifiers into multipulse arrangements is seen to be effective for both shunt and series APFs. The ratings are approximately halved for the 12-pulse case.

In this study, the equation for the reactive and harmonic power compensation of a shunt active power filter (APF) system has been derived by studying the power exchange mechanism and power tetrahedron phasor diagram. The switching dynamics of a voltage source inverter (VSI)‐based three‐phase, three‐wire (three‐leg /half‐bridge) shunt APF system with hysteresis band current control has been studied and verified by simulation. The relation between the design parameters and their effects on the active losses has also been identified. Detailed calculation and extensive simulation have been performed for a three‐phase, three‐wire shunt APF implemented in a 400 V L–L distribution system, as an example, to study the effects of design parameter selection and their role in active power loss calculation. Simulated and calculated results are presented for the important design parameters for different switching frequencies together with their associated losses and kVA ratings. The procedure can be followed to design the parameters for other topologies, such as three‐phase, four‐wire or single‐phase systems.

This paper presents a novel control scheme for unified power quality conditioner (UPQC) based on three-level neutral point clamped (NPC) inverter using fuzzy logic and Ann's for controlling respectively series and shunt APFs. The proposed UPQC is able to mitigate source current harmonics and compensate all voltage disturbances. It is designed by the integration of series and shunt active filters (AFs) sharing a common DC bus capacitor. The DC voltage is maintained constant using proportional integral voltage controller. The synchronous reference frame (SRF) theory is used to get the reference signals for the shunt APF and the power reactive theory (P-Q theory) for the series APF. The shunt and series active power filter (APF) reference signals derived from the control algorithm and sensed signals are injected in two intelligent controllers to generate switching signals. The performances of the proposed UPQC system are evaluated using Matlab-Simulink software and SimPowerSystem Toolbox. The simulation results show the performance of the proposed UPQC at the common connection point of the non-linear load to improve the power energy quality.

This paper includes assay and correlation of three phase shunt active to extricate its reference currents with distinct control strategies to evaluate their dynamic performance under different load conditions for both Shunt Active Power Filter (SAPF) and Hybrid Shunt Active Power Filter (HSAPF). The instantaneous active and reactive power (p-q) theory and synchronous reference frame theory (SRF) are compared. Extensive simulations are carried out for p-q and d-q theory’s for both shunt APF and hybrid shunt APF with PI controller. The compensation capability of Hybrid shunt APF is greater than SAPF for harmonics, reactive power compensation and dynamic performances capability. Performances comparison is analyzed using Matlab/Simulink. Simulation outcome is given to compare and validate the control techniques for SAPF and HSAPF during load changing condition.

The current paper presents a role of Unified Power Quality Conditioner (UPQC) in 3 phase 4 wire distribution system to improve the power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, d-q-0 theory is used. For the control of shunt APF, Clark transformation concept is applied. The performance of the applied control algorithm is evaluated in terms of source neutral current mitigation, mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained.

PI and fuzzy logic controllers for shunt active power filter — A report

This paper presents a shunt active power filter for power quality enhancement in terms of harmonics and reactive-power compensation due to the non-linear loads in the distribution network. The compensation approach uses calculation of real-power (p) losses only, which is simpler and different from the conventional p-q theory. The voltage source inverter based active filter switching pulses are generated from adaptive-Hysteresis Current Controller (HCC). This adaptive-HCC changes the hysteresis-bandwidth according to the instantaneous compensation current variation that is used to optimize the required switching frequency. This would improve the active power filter performances. The three-phase shunt active power filter system is investigated under both steady state and transient conditions with non-linear loads.

The basic principle of shunt active power filter(SAPF) is that the output compensation current is equal to the harmonic current with reverse direction, the performances of SAPF contain dynamic response and static precision. Aiming at the defect of PI control applying to SAPF has low static precision, compound control method based on putting repetitive control and PI control in series-shunt is put forward. The repetitive control is used to improve the static precision of harmonic compensation and the PI control is used to improve dynamic response. Emulated results indicate the series-shunt compound control has better performances than single PI control and shunt compound control. The experimental results verify the viability and effectiveness of the proposed method.

Harmonics in the power system can be reduced and thus power quality can be improved with the use of Active power filter. In this literature, fixed switching frequency single phase shunt active filter based on sliding mode controller is modeled and analyzed using MATLAB. Control law is designed to generate both continuous and discontinuous component of the control signal. Pulse width modulated switching signals to the shunt active power filter are generated from the Control output of the sliding mode controller. DC link capacitor voltage is controlled using PI controller which gives the reference source current. Performance of single phase shunt active power filter with nonlinear and combined nonlinear and linear load is demonstrated with the help of simulation results.

The existing solutions for reducing total harmonic distortion (THD) using different control algorithms in shunt active power filters (SAPFs) are complex. This work proposes a split source inverter (SSI)-based SAPF for improving the power quality in a nonlinear load system. The advantage of the SSI topology is that it is of a single stage boost inverter with an inductor and capacitor where the conventional two stages with an intermediate DC-DC conversion stage is discarded. This research proposes inventive control schemes for SAPF having two control loops; the outer control loop regulates the DC link voltage whereas the inner current loop shapes the source current profile. The control mechanism implemented here is an effective, less complex, indirect scheme compared to the existing time domain control algorithms. Here, an intelligent fuzzy logic control regulates the DC link voltage which facilitates reference current generation for the current control scheme. The simulation of the said system was carried out in a MATLAB/Simulink environment. The simulations were carried out for different load conditions (RL and RC) using a fuzzy logic controller (FLC) and PI controllers in the outer loop (voltage control) and hysteresis current controller (HCC) and sinusoidal pulse width modulation (SPWM) in the inner loop (current control). The simulation results were extracted for dynamic load conditions and the results demonstrated that the THD can be reduced to 0.76% using a combination of SPWM and FLC. Therefore, the proposed system proved to be effective and viable for reducing THD. This system would be highly applicable for renewable energy power generation such as Photovoltaic (PV) and Fuel cell (FC).

This chapter explains excellent performance of shunt active power filter (SAPF) integrated with photovoltaic source, for considerable energy management, harmonic alleviation, and reactive power recompense. The solar plant produces extreme or equal power essential to the load requirement, hence the coordination with grid is complex. The PV module is designed with INC-MPPT technology, and the shunt active power filter is connected at the AC side of the inverter integrated with a nonlinear load. Here, the shunt active power filter design depends on PI controller whose gains are selected arbitrary. In the first study, the total harmonic distortion (THD) is calculated with no filter and nonlinear load. Then, THD analysis is performed with SAPF. Further to pick up the recital of shunt active power filter, a new PSO optimization technique is applied to select the proper value of PI gains R and L of nonlinear load. The simulation result depicts that the optimized shunt active filter reduces harmonics to a great extent. The results of SAPF, PSO-SAPF, APSO-SAPF, and TCPSO-SAPF are compared.

The non-linear devices used in the present environment like computers, printers, lasers, smps, rectifiers etc. pollutes the power system by harmonics and reactive power. Due to the presence of harmonics in the power system a number of undesirable effects caused in the distribution network. To find the solution for this the active power filter (APF) is one of the suitable solutions, which compensates Harmonics as well as reactive power simultaneously. This paper presents a active power line conditioning system to improve the power quality in the distribution network and implementation of a digital controller using 8051 microcontroller. The active power line conditioner is implemented with Pulse Width Modulation (PWM) based current controlled voltage source inverter (VSI). The Digital Controller is designed using MCS 8051 microcontroller which becomes independent of process technology. Synchronous reference frame (SRF) is used for generation of reference current. The PI current algorithm is implemented using MATLAB platform. The shunt APF is modeled and investigated under different unbalanced non-linear load conditions in MATLAB/SIMULINK. The simulation results reveals that the active power filter is efficiently compensating the current harmonics and reactive power in the distribution network. The APF system is in compliance with the IEEE 519 and IEC 61000-3 recommended standards.

Suitable model for the analysis and control of the shunt active power filter (APF) was quite difficult to obtain, which prohibited not only the industrial applications, as no generalized method to design the control loop, also the analysis and comparison between existing control methods. In this paper, a simplified shunt APF model, including the steady state model and small signal model, based on the instantaneous energy equilibrium is proposed. Subsequently, the newly built model is used to analyze two popular control methods in detail, as the shunt APF control with or without the reactive and harmonic current detection, in the DC voltage control loop responses to different load current disturbances. The obtained results are compared with the time domain simulation results for the control method with the reactive and harmonic current detection, the differences for them are found as the time delay caused by the low path filter (LPF) in the detection, the control and the whole system model is improved by considering this effect, and the comparisons on the responses to different current disturbances are evaluated for these two control methods accordingly. Finally, an example of the shunt APF control loop design is done based on the new model in the control method without reactive and harmonic current detection, the computer simulation and the prototype experiment are done to verify the validity of this newly designed compensator accordingly.

Active power filters are the emerging devices, which can diminish harmonic pollution effectively. Most of the proposed control strategies for power quality improvements have been reviewed with regard to performance and implementation. It has been seen that there has been a significant increase in interest of active power filters and its control methods. Mathematical model of Shunt Active Power filter is implemented with Instantaneous Reactive Power theory. Performance of Three-phase Four-wire Shunt Active Power Filter is analyzed here with Proportional and Integral controller and Proportional Integral and Derivative Controller. Simulation is done in MATLAB to verify the results.

A medium power Current Source Converter (CSC) based Active Power Filter (APF) system is designed and implemented to suppress the amplification of low order harmonics at the Medium Voltage (MV) interface bus between the distribution and transmission systems, owing to the presence of large shunt capacitor banks installed only for reactive power compensation. For this purpose, four CSC based APF units designed at 1.0 kV are operated in parallel, and connected to the 31.5 kV MV bus via a specially designed coupling transformer. In each APF module, a specially designed LC-type input filter eliminates the switching ripples, and active damping method embedded into the control software suppresses harmonic frequencies around the natural frequency of the input filter. The resulting system can operate at relatively high frequencies in the range from 2.0 to 3.0 kHz, depending upon which selected harmonics among 5th, 7th, 11th, and 13th are to be eliminated. Furthermore, in order to reduce the installed capacity of CSCs, Selective Harmonic Amplification Method (SHAM) is applied to the APF system described in the paper. MV APF system has been built as a mobile system for temporary connection to a problematic MV interface bus, until a permanent solution is found for that location in the distribution system.