State variable feedback predictive control design for single phase shunt active power filter

Due to the proliferation of non-linear modern power electronics, currents and voltages produced by non-linear loads have lead to the deterioration and distortion of the output sine wave forms of the source currents and voltages. These distortions have resulted in the power quality problems. The non-linear load draws reactive power and harmonics from the ac source in the fundamental current. The harmonics in power system caused by non-linear loads such as, arc furnaces, switch mode power supply, fluorescent lamps rectifiers etc all are the main sources of harmonics, as a result of these non-linear loads the supply system lead to overheating of cables and conductors, electromagnetic interference to nearby communication facilities etc. Therefore, as a result of theses harmonics, a traditional passive filters are used to suppressed the integer multiple fundamental frequencies, but due to the passive filter draws back in producing series or parallel impedance with the supply impedance and heavy in sized, its limitations in service becomes an old scheme. The application of shunt active power filter in mitigating these harmonics problems supersedes the used of passive filter. This paper, presents the modeling and simulation of single-phase shunt active power filter controlled with fuzzy logic controller (FLC) to mitigate the harmonics drawn by non-linear loads. The proposed scheme is performed by using MATLAB fuzzy tool box environment. Simulation results obtained by the proposed control algorithm found to be satisfied and within the recommended imposed IEEE 519-1992 harmonic standard limit.

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.

Advanced Nonlinear Control of Single Phase Shunt Active Power Filter Based on Full Bridge Dual Buck Converter

This paper presents a single phase shunt active power filter for compensating the power factor and harmonics currents generated by two nonlinear loads, an AC controller with resistive load, and a rectifier with an inductive load. The topology of the filter is based on a single phase inverter with four IGBTs. The filter current is forced to follow a reference; this reference current must be the difference between the sinusoidal input current in phase with the sinusoidal voltage supplying the load and the load current; for calculating the reference current a frequency-independent method has been used. The calculus of the reference current and results of simulation are presented; finally experimental results obtained from a prototype confirm the feasibility of the proposed system.

This paper describes a single-phase modified packed U-cell seven-level multilevel inverter (MPUC7) with finite control set model predictive control (FCS-MPC) for a single phase shunt active power filter application. The shunt active filter can directly inject the harmonic load current and compensate for the reactive power of the load and thus, make the grid current sinusoidal and in-phase with the grid voltage. The active filter improves the power factor and THD of current at point of common coupling (PCC). The MPUC7 is a six switch seven level inverter with only two dc-link capacitors. The mathematical model of shunt connected MPUC7 converter is explained for derivation of the next sample prediction required for FCS-MPC. The cost function for the constraint of tracking current and regulating the two dc-link voltage is mentioned. The filter reference currents are derived using direct control method. The single-phase active filter application is simulated in the Matlab/Simulink to validate the operation and robustness of the FCS-MPC current controller. Various non-linear load changes are simulated to verify the effect on dynamic operation.

This paper studies a single phase shunt active power filter (APF) using a bi-directional full-bridge converter with capacitive energy storage to compensate for the harmonics generated by nonlinear loads. The usage of a capacitor as a reactive power source for the APF simplifies the circuitry. The harmonic current reference is obtained by feeding the load current signal into a 50 Hz notch filter. The simple and fast hysteresis control strategy involving only a few analog and logic components makes it attractive for the low power domestic application. The usefulness of the proposed control algorithm is confirmed by simulation as well as by experimental results.

A new control scheme for a single phase shunt Active Power Filter (APF) is proposed in this paper. The goal is the introduction of a new reference generator along with a repetitive current control scheme. The proposed reference generator uses a filter based on a sinusoidal signal integrator and the instantaneous reactive power theory to compute the APF reference current. The proposed scheme can be easily adapted to work in a distributed generation system, injecting active power into the grid. The whole control algorithm has been implemented on the dSPACE DS1103 development system controlling a single phase APF prototype to demonstrate the feasibility of the proposed solution.

Three phase Shunt Active Power Filters (SAPF) are widely used to inject required amount of compensating current to eliminate current harmonics generated by Non-Linear Loads (NLL) and restore sinusoidal waveform of the supply. This paper analyze the development of a three phase grid connected PV array generating a P&O algorithm based MPPT tracked DC power, converted to AC power by PLL controlled VSI supplying a NLL connected with SAPF constituting of series inductor, ANN based self-supported DC link capacitor connected to IGBT based Current controlled VSI compensating for load induced current harmonics in the line. The developed SAPF works on instantaneous active and reactive power measurements to calculate the reference current for the HBCC to produce the gate pulse for the inverter. The proposed model is developed in MATLAB 17a Simulink and Levenberg Marquardt training algorithm based ANN is implemented to regulate DC link capacitor voltage. Simulated results approves the proposed control technique for a fast and flexible dynamic response of the solar to three phase compensated grid system and Total Harmonic Distortion of supply current is found to be satisfactory as per the IEEE-519 standards.

Shunt active power filter is a complete current source which can provide a effective and adjustable solution for elimination of harmonic currents in power system. Its performance, depends on strategy employed in reference current generation, control technique and topology of inverter used in the design. In this study, fuzzy logic current control technique was presented for generation of pulse for PWM current control of the three phase inverter. A band pass filter was used in synchronous reference frame algorithm (SRF) for harmonics extraction. The shunt active power filter performance was evaluated with MATLAB/SIMULINK under balanced voltage condition. The result obtained gives good and satisfactory response to mitigate the harmonics in the system.

In this paper, instantaneous reactive power theory (IRP), also known as p-q theory based a new control algorithm is presented for 3-phase 3-wire and 3-leg shunt active power filter (SAPF) to suppress harmonic currents and compensate reactive power under non ideal voltage sources. The reference current signals are generated by sensing the source voltage, load current and dc bus voltage. With these signals the driving signals are generated via hysteresis band PWM current controller. To check robustness of the control algorithm four different cases such as ideal, unbalanced, balanced distorted and unbalanced distorted main voltage are considered and simulated with different firing angle of the load. The simulation work is carried out in MATLAB/SIMULINK Power system block set. The performance of the proposed algorithm is found quite effective and satisfactory under non-ideal main voltage conditions.

Shunt active power filters (shunt APFs) represent the most important and most widely used filters in industrial purposes, this is due not only to the fact that they eliminate the harmonic current with a neglected amount of active fundamental current supplied to compensate system losses, but also they are suitable for a wide range of power ratings. Modern power electronic devices such as IGBTs allowed to configure non- harmonic generating shunt APFs, this paper focuses on this type of configuration namely the voltage source inverter based three- phase shunt active power filters aiming to present an overview on the mater.

Shunt Active Power Filters (SAPF) are commonly employed to reduce current harmonics, which are injected in the utility by nonlinear loads. This paper presents performance of current error space phasor based hysteresis controller for three-level Neutral Point Clamped (NPC) and Flying Capacitor (FC) converters used in SAPF. Operation of two-level converter based SAPF is also demonstrated in this paper with the proposed controller. The proposed controller is self-adaptive in nature and does not require any particular calculation of Point of Common Coupling (PCC) voltage vector (E) because of proper sector change detection logic used. The proposed current controller overcomes inherent problem of random voltage vector switching encountered in conventional hysteresis current controller based SAPFs. It allows switching of only adjacent voltage vectors for position of PCC voltage vector in a given sector of voltage space phasor of SAPF. Region detection logic causes switching of SAPF voltage vector which keeps the current error well within the prescribed hexagonal boundary. The SAPF based on the proposed controller provides adequate compensation for removal of harmonics produced by nonlinear loads. Detailed theoretical analysis and simulation studies are presented in the paper and the claimed performance of the proposed controller is evident from the simulation results provided in the paper. This paper addresses issues like dc-link capacitor voltage unbalance for NPC and clamping capacitor voltage unbalance for Flying Capacitor based SAPF and also provides solution. The proposed controller can be easily extended for any multi-level converter topology used for SAPFs.

This paper presents the design and implementation of the insulation and conditioning cards for sensors that measure voltage and current signals for to be applied to harmonic control and compensation in an Active Power Filter (APF). Then describes the characteristics and mathematical algorithm in the time domain technique used to obtain the reference current applied to digital control of a Shunt Single Phase Active Power Filter. Finally presents the simulation and integration of the instrumentation system with the algorithm to obtain reference currents implemented in a Digital Signal Processor (DSP) 56F8323 of Freescale®.

Current harmonics injected in the utility by nonlinear loads tend to deteriorate the power quality at the mains. These harmonics are compensated by Shunt Active Power Filters (SAPF). Current error space phasor based hysteresis controller for SAPF is presented in this paper, which allows precise compensation of harmonic currents produced by non-linear loads. Because of proper sector change detection logics, the proposed controller is self-adaptive in nature and does not require any particular calculation of voltage vector at the Point of Common Coupling (PCC). The controller operation is studied for two different self-adaptive logics for detection of sector changes - one with outer hysteresis band, and the other without using outer hysteresis band. The proposed controller based SAPF using outer hysteresis band compensates harmonics in supply current effectively. Distortion in supply current is further reduced by avoiding the outer hysteresis band and generating the SAPF compensating currents by synchronizing the sector change with supply frequency. The controller keeps the current error space phasor within the hexagonal boundary (fixed band) by applying SAPF voltage vectors which are adjacent to the reference voltage vector (voltage vector at the PCC). This leads to the switching of optimal voltage vector unlike the random selection of the voltage vectors in conventional hysteresis controller based schemes. Performance of the proposed controller based SAPF is analyzed for dc-link voltage regulation scheme of reference compensating current generation. The performance of controller is tested for balanced as well as unbalanced mains voltage and is found satisfactory. Experimental validations of the proposed controller based SAPF for sector change detection with and without using outer hysteresis band are presented. Detailed theoretical analysis, modelling, simulation and experimental studies are carried out and the claimed performance of the proposed controller is evident from the results presented in the paper.

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.