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Proceedings ArticleDOI

Robust control design of Grid power converters in improving power quality

24 Jun 2015-pp 460-465
TL;DR: In this paper, a grid connected PV inverter incorporating the improvement of power quality issues in its controller design is used for eliminating steady state error and for the fast dynamic response, a repetitive controller is used to track periodic reference signals and to compensate harmonic disturbances.
Abstract: This paper focuses on grid connected PV inverter incorporating the improvement of power quality issues in its controller design Proportional resonant (PR) controller is used for eliminating steady state error and for the fast dynamic response A repetitive controller is used for tracking periodic reference signals and to compensate harmonic disturbances To attain low THD and quick steady state process, feed forward approach is implemented in controller design The stability of the voltage and current controller is examined in bode plot Phase locked loop (PLL) synchronization technique with LCL filter is also examined A single phase Grid connected 3Kw PV inverter is modeled and simulated in MATLAB/Simulink/PLECS environment with the accurate results in its waveform
Citations
More filters
Journal ArticleDOI
TL;DR: An improved passive damping is examined with reduction of power loss for the LLCL filter and it reduces the switching ripple much better than LCL filter, with a decrease in volume of the inductance.
Abstract: The third order LLCL filter is gaining more attractive in grid connected PV inverter in terms of material cost saving than LCL filter Several active and passive damping techniques prevail in mitigating the resonance problem for maintaining the grid power quality standards In this paper an improved passive damping is examined with reduction of power loss for the LLCL filter Particularly, it reduces the switching ripple much better than LCL filter, with a decrease in volume of the inductance The filter design is also developed for the operation of stiff grid Mathematical operations and transfer function are derived with frequency response for the accuracy of the filter design In addition, comparative analysis of passive and improved passive damping control is proposed The control strategy is improved with feedback linearization in order to avoid the glitches in inverter control and is verified with prototype grid connected PV inverter

9 citations


Cites background from "Robust control design of Grid power..."

  • ...Compared to L filter, LCL filter is proved to have a better harmonic attenuation for the reduction of filter inductance volume [14] which bypass the high frequency harmonics through the capacitance branch....

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Proceedings ArticleDOI
11 Apr 2021
TL;DR: In this paper, the authors proposed a robust current controller for single-phase grid-feeding voltage source inverter with an LCL filter, which has good reference tracking, disturbance rejection and sufficient LCL resonance damping under a large range of variations of grid impedance.
Abstract: This article proposes the design of H ∞ -based robust current controller for single-phase grid-feeding voltage source inverter with an LCL filter. The main objective of the proposed controller is to have good reference tracking, disturbance rejection and sufficient LCL resonance damping under a large range of variations of grid impedance. Based on the aforementioned performance requirements, frequency dependent weighting functions are designed. Subsequently, the sub-optimal control problem is formulated and solved to determine the stabilizing controller. Computational footprint of the controller is addressed for ease-of-implementability on low-cost controller boards. Finally controller hardware-in-the-loop simulations on OPAL-RT are performed in the validation stage to obtain performance guarantees of the controller. The proposed controller exhibits fast response during transients and superior reference tracking, disturbance rejection at steady-state when compared with proportional- and resonant-based current controllers.

4 citations

Proceedings ArticleDOI
01 Dec 2016
TL;DR: In this paper, a three phase grid connected photovoltaic generation system with new approach for reactive power regulation is presented, which operates as an reactive power compensator, generated by the other load connected to system.
Abstract: An advanced Solar Photovoltaic plant controllers designed to improve system performance, reduce the need for ancillary services, and provide ancillary services instead of or in competition with conventional resources. This paper presents control model of three phase grid connected photovoltaic generation system with new approach for reactive power regulation. In order to maximize the power output, components of Photovoltaic System should be optimized. For the optimization maximum power point tracking (MPPT) is a promising technique that grid connected inverters use to get the maximum possible power from solar PV array. The model of the SPWM inverter and a control strategy using park transformation are proposed the system operates as an reactive power compensator, generated by the other load connected to system. Renewable power generation systems utilizing power electronics converters rely on accurate grid phase angle determination in order to successfully close grid voltage vector oriented control loop usual for this kind of application. A three phase grid connected voltage source inverter synchronizes to the grid by a robust phase lock loop (PLL).

4 citations

Proceedings ArticleDOI
15 Oct 2022
TL;DR: In this article , a whale-inspired optimization technique is used to identify the global maximum location (GML) among the existence of many local maximum locations during partial shading conditions, and a novel controller is proposed for the inverter to work as a single stage grid connected PV system.
Abstract: Many maximum power point tracking (MPPT) techniques are widely used to harvest maximum energy from Photovoltaic (PV) panels. Among those perturb and observe (P&O) method is an effective technique to work in the condition of uniform irradiance. However, an optimization algorithm is required to identify the global maximum location (GML) among the existence of many local maximum locations during partial shading conditions. The Whale inspired algorithm is a famous optimization technique to identify GML quickly as compared with many optimization algorithms. Usually a single stage grid connected PV system is a more efficient and economical method in medium power generations due to absence of an extra DC to DC converter. The interfacing inverter between PV and grid itself is working as a MPPT converter by regulating DC link voltage at GML. In this scenario, a whale inspired optimization technique can help to harvest more energy by a proper inverter controller. The H∞ controller can help to get fast response as well as to make the system more stabilized. Therefore, in this paper a novel controller is proposed for the inverter to work as a single stage grid connected PV system. The quality of power can also be supplied to the grid by the proposed controller. Extensive results based on Hardware-in the-Loop (HIL) are presented in this work on the platform of OPAL-RT technologies.

1 citations

Journal ArticleDOI
TL;DR: In this paper , a generalized control framework is proposed for both grid following and grid forming inverters to address the large uncertainty of the grid impedance in micro-grid systems, and a combined system-in-the-loop, controller hardware in the loop, and power hardware in-theloop based experimental validation is conducted to evaluate the efficacy and viability of the proposed controllers.
Abstract: Grid-following and grid-forming inverters are integral components of microgrids and for integration of renewable energy sources with the grid. For grid following (GFL) inverters, which need to emulate controllable current sources, a significant challenge is to address the large uncertainty of the grid impedance. For grid forming (GFM) inverters, which need to emulate a controllable voltage source, large uncertainty due to varying loads has to be addressed. This article presents a generalized control framework by leveraging the voltage-current duality in the plant dynamic model of GFL and GFM inverters. The modeling of uncertainties is also generalized under the control framework by quantifying the uncertainties in grid impedance parameters and the uncertainties in equivalent loading parameters for GFL and GFM inverters, respectively. Based on the generalized control framework, a $\boldsymbol{\mu}$ -synthesis-based robust control design methodology is proposed for both GFL and GFM inverters. The control objectives, while designing the proposed optimal controllers, are reference tracking, disturbance rejection, and harmonic compensation capability with ${i})$ sufficient ${LCL}$ resonance damping under large variations of grid impedance uncertainty for GFL inverters and ${ii})$ with enhanced dynamic response under large variations of equivalent loading uncertainty for GFM inverters. A combined system-in-the-loop, controller hardware-in-the-loop, and power hardware-in-the-loop based experimental validation on $\mathbf {10}$ -kVA microgrid system with two physical inverter systems is conducted in order to evaluate the efficacy and viability of the proposed controllers.

1 citations

References
More filters
Journal ArticleDOI
TL;DR: In this article, the P+Resonant regulator is proposed, which achieves the same transient and steady-state performance as a synchronous frame PI regulator and is applicable to both single-phase and three-phase inverters.
Abstract: Current regulators for AC inverters are commonly categorized as hysteresis, linear PI, or deadbeat predictive regulators, with a further sub-classification into stationary ABC frame and synchronous d-q frame implementations. Synchronous frame regulators are generally accepted to have a better performance than stationary frame regulators, as they operate on DC quantities and hence can eliminate steady-state errors. This paper establishes a theoretical connection between these two classes of regulators and proposes a new type of stationary frame regulator, the P+Resonant regulator, which achieves the same transient and steady-state performance as a synchronous frame PI regulator. The new regulator is applicable to both single-phase and three phase inverters.

1,295 citations

Book
01 Jan 2002
TL;DR: In this article, the authors present a comparison of Torque Control Strategies based on the Constant Power Loss Control System for PMSM for three-phase PWM rectifiers and motors.
Abstract: Part I: PWM Converters: Topologies and Control 1 Power Electronic Converters 2 Resonant dc Link Converters 3 Fundamentals of the Matrix Converter Technology 4 Pulse Width Modulation Techniques for Three-Phase Voltage Source Converters Part II: Motor Control 5 Control of PWM Inverter-Fed Induction Motors 6 Energy Optimal Control of Induction Motor Drives 7 Comparison of Torque Control Strategies Based on the Constant Power Loss Control System for PMSM 8 Modeling and Control of Synchronous Reluctance Machines 9 Direct Torque and Flux Control (DTFC) of ac Drives 10 Neural Networks and Fuzzy Logic Control in Power Electronics Part III: Utilities Interface and Wind Turbine Systems 11 Control of Three-Phase PWM Rectifiers 12 Power Quality and Adjustable Speed Drives 13 Wind Turbine Systems Index

727 citations

Proceedings ArticleDOI
27 Sep 2004
TL;DR: In this article, a new control strategy aimed to mitigate the PI current control of a single-phase inverter has been proposed, where Stationary-frame generalized integrators are used to control the fundamental current and to compensate the grid harmonics providing disturbance rejection capability without the need of feed-forward grid compensation.
Abstract: The PI current control of a single-phase inverter has well known drawbacks: steady-state magnitude and phase error and limited disturbance rejection capability. When the current controlled inverter is connected to the grid, the phase error results in a power factor decrement and the limited disturbance rejection capability leads to the need of grid feed-forward compensation. However the imperfect compensation action of the feed-forward control results in high harmonic distortion of the current and consequently noncompliance with international standards. In this paper a new control strategy aimed to mitigate these problems is proposed. Stationary-frame generalized integrators are used to control the fundamental current and to compensate the grid harmonics providing disturbance rejection capability without the need of feed-forward grid compensation. Moreover the use of a grid LCL-filter is investigated with the proposed controller. The current control strategy has been experimentally tested with success on a 3 kW PV inverter.

434 citations

Journal ArticleDOI
TL;DR: In this article, a two-layer controller consisting of a tracking controller and a repetitive controller is proposed to improve both the transient and steady-state responses of a closed-loop regulated pulsewidth-modulated (PWM) inverter for high-quality sinusoidal AC voltage regulation.
Abstract: This paper proposes a new control scheme based on a two-layer control structure to improve both the transient and steady-state responses of a closed-loop regulated pulse-width-modulated (PWM) inverter for high-quality sinusoidal AC voltage regulation. The proposed two-layer controller consists of a tracking controller and a repetitive controller. Pole assignment with state feedback has been employed in designing the tracking controller for transient response improvement, and a repetitive control scheme was developed in synthesizing the repetitive controller for steady-state response improvement. A design procedure is given for synthesizing the repetitive controller for PWM inverters to minimize periodic errors induced by rectifier-type nonlinear loads. The proposed control scheme has been realized using a single-chip digital signal processor (DSP) TMS320C14 from Texas Instruments. A 2-kVA PWM inverter has been constructed to verify the proposed control scheme. Total harmonic distortion (THD) below 1.4% for a 60-Hz output voltage under a bridge-rectifier RC load with a current crest factor of 3 has been obtained. Simulation and experimental results show that the DSP-based fully digital-controlled PWM inverter can achieve both good dynamic response and low harmonics distortion.

279 citations

Proceedings ArticleDOI
06 Oct 1996
TL;DR: Algorithms for directly implementing a predictive current controller in a microprocessor for load situations where the back-EMF is both known and unknown are presented.
Abstract: The three major approaches for regulating current in hard switched inverters are ramp comparison, hysteresis control and predictive current control. Of these three, predictive current control offers the potential for achieving more precise current control with minimum distortion and harmonic noise, but is generally more difficult to implement and usually must be matched to a specific load. Also, errors caused by computational delays create further problems in a real system. This paper presents algorithms for directly implementing a predictive current controller in a microprocessor for load situations where the back-EMF is both known and unknown. The algorithms fully compensate for sampling delays and discretisation errors, and are simple enough to be readily implemented in a practical system. Both simulation and experimental results are presented as confirmation of the approach presented.

228 citations