PMSG Based WECS with PR Control Strategy for Grid Control

2014 ◽  
Vol 573 ◽  
pp. 267-272
Author(s):  
V. Prasath ◽  
S. Vijayalakshmi ◽  
R. Jain Anush
Keyword(s):  
Control Strategy ◽  
Harmonic Distortion ◽  
High Gain ◽  
System Control ◽  
Control Loop ◽  
Current Feedback ◽  
Lcl Filter ◽  
Order Function ◽  
Average Value ◽  
Pr Controller

In this paper, a current feedback control scheme is proposed using Proportional Resonant (PR) for a grid-connected converter with an LCL Filter; PR controller with harmonic compensators has high gain at the desired frequencies for decrease harmonic distortion in the alternative voltage or current. Harmonic compensators of PR controller are limited to several low-order harmonics due to the system instability when the compensated frequency is out of system control loop’s bandwidth. The average value of current flow through inductors of LCL filter is feedback to the PR current regulator. Zero D-axis Control (ZDC) is to control the generator side converter to reduce the DC-link ripples, multi-loop harmonic current controllers are applied to regulate the higher-order harmonics by PR regulators. Consequently control strategy with LCL filter is to reduce third-order function to first-order function. By this way large control loop gain can be chosen to obtain control loop for the required harmonic components of the PR controller. The simulation and experimental results have been illustrated to validate the effectiveness of the proposed method in MATLAB Simulink.

scholarly journals Potency of PR controller for multiple harmonic compensation for a single-phase grid connected system

2020 ◽  
Vol 11 (3) ◽  
pp. 1491
Author(s):  
D Sattianadan ◽  
Soumen Gorai ◽  
G. R. Prudhvi Kumar ◽  
S. Vidyasagar ◽  
V. Shanmugasundaram
Keyword(s):  
Single Phase ◽  
Harmonic Distortion ◽  
System Stability ◽  
Phase System ◽  
Pv System ◽  
Lcl Filter ◽  
Grid Synchronization ◽  
Harmonic Content ◽  
Wide Range ◽  
Pr Controller

<p><span lang="EN-US">Harmonics and grid synchronization are one of the major problems faced when dealing with a single-phase system. The development of technology in the PV system makes the consumer to use it in a wide range. The power transferred from PV to grid needs DC to AC conversion process which is done by static devices operating with the higher frequencies that causes the harmonics in the grid connected system. The main aim of the paper is to implement grid synchronization and reduce total harmonic distortion in a single-phase grid connected system. The design of LCL filter is addressed in this paper which depends on current ripple, filter size and switching ripple attenuation.  In order to account the harmonic content, the FFT analysis is made both in analysis and Matlab Simulink. The Proportional Resonant (PR) controller is developed and work along with LCL filter for reducing the harmonic content. The stability of the system with PR is analyzed using root locus and bode plots and results are compared with PI controls. The result shows that PR controller performs better compared to the PI controller for reducing the harmonic content present in the single-phase system and for improving the system stability.</span></p>

Decoupled Control Strategy of Grid Interactive Inverter System with Optimal LCL Filter Design

2013 ◽  
Vol 14 (5) ◽  
pp. 477-486 ◽  
Author(s):  
B. Chitti Babu ◽  
Anup Anurag ◽  
Tontepu Sowmya ◽  
Debati Marandi ◽  
Satarupa Bal
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Filter Design ◽  
Dynamic Performance ◽  
Harmonic Distortion ◽  
Voltage Source ◽  
Lcl Filter ◽  
Current Harmonics ◽  
Switching Losses ◽  
Active And Reactive Power

Abstract This article presents a control strategy for a three-phase grid interactive voltage source inverter that links a renewable energy source to the utility grid through a LCL-type filter. An optimized LCL-type filter has been designed and modeled so as to reduce the current harmonics in the grid, considering the conduction and switching losses at constant modulation index (Ma). The control strategy adopted here decouples the active and reactive power loops, thus achieving desirable performance with independent control of active and reactive power injected into the grid. The startup transients can also be controlled by the implementation of this proposed control strategy: in addition to this, optimal LCL filter with lesser conduction and switching copper losses as well as core losses. A trade-off has been made between the total losses in the LCL filter and the Total Harmonic Distortion (THD%) of the grid current, and the filter inductor has been designed accordingly. In order to study the dynamic performance of the system and to confirm the analytical results, the models are simulated in the MATLAB/Simulink environment, and the results are analyzed.

scholarly journals Energy Storage System Control for Energy Management in Advanced Aeronautic Applications

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
A. Cavallo ◽  
G. Canciello ◽  
B. Guida
Keyword(s):  
Energy Management ◽  
High Voltage ◽  
Control Strategy ◽  
Storage System ◽  
Electric Energy ◽  
Gain Control ◽  
Energy Storage System ◽  
High Gain ◽  
System Control ◽  
High Level

In this paper an issue related to electric energy management on board an aircraft is considered. A battery pack is connected to a high-voltage bus through a controlled Battery Charge/Discharge Unit (BCDU) that makes the overall behaviour of the battery “intelligent.” Specifically, when the aeronautic generator feeding the high-voltage bus has enough energy the battery is kept under charge, while if more loads are connected to the bus, so that the overload capacity of the generator is exceeded, the battery “helps” the generator by releasing its stored energy. The core of the application is a robust, supervised control strategy for the BCDU that automatically reverts the flow of power in the battery, when needed. Robustness is guaranteed by a low-level high gain control strategy. Switching from full-charge mode (i.e., when the battery absorbs power from the generator) to generator mode (i.e., when the battery pumps energy on the high-voltage bus) is imposed by a high-level supervisor. Different from previous approaches, mathematical proofs of stability are given for the controlled system. A switching implementation using a finite-time convergent controller is also proposed. The effectiveness of the proposed strategy is shown by detailed simulations in Matlab/Stateflow/SimPowerSystem.

scholarly journals A Control Strategy of a Single-phase H6-type Grid-connected Inverter with Low Harmonic Current

2018 ◽  
Vol 173 ◽  
pp. 02041
Author(s):  
Lin Chunxu ◽  
Zhou Chunhua ◽  
Li Wei ◽  
Chen Rui
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Closed Loop ◽  
High Efficiency ◽  
Control Method ◽  
Harmonic Distortion ◽  
Outer Loop ◽  
Lcl Filter ◽  
Loop Control ◽  
Grid Connected Inverter

In order to reduce the total harmonic distortion (THD) of the grid-connected current caused by the high-frequency switching of the inverter, this paper combines the high efficiency single-phase H6-type inverter with LCL filter. The double closed-loop control method that consists of grid-connected current outer loop and capacitor current inner loop is put forward, by which a resonance peak of a low damping LCL filter is eliminated. In the grid-connected current outer loop, quasi proportion resonant (QPR) controller is adopted to overcome the steady-state error and weak anti-jamming capability in traditional PI controller. Finally, a simulation model is built in SIMULINK to verify the research. The simulation results show that, based on the single-phase H6-type inverter and LCL filter, the double closed-loop QPR control strategy can achieve the static error free tracking control of grid-connected current, which makes the system more stable and reduces the THD of grid-connected current effectively.

scholarly journals A Photo-Voltaic Invert-er Cluster Resonance Suppression Method Based on Capacitor Voltage Feed-Forward

2021 ◽  
Vol 2136 (1) ◽  
pp. 012012
Author(s):  
Shengqing Li ◽  
Xin Yao ◽  
Ziran Peng ◽  
Zhichao Shen
Keyword(s):  
Control Structure ◽  
System Control ◽  
Current Feedback ◽  
Lcl Filter ◽  
Feed Forward ◽  
Weak Grid ◽  
Capacitor Voltage ◽  
Simulation And Experiment ◽  
Suppression Method ◽  
Photo Voltaic

Abstract Photo-voltaic inverts usually use LCL filter for filtering, and LCL filter will bring resonance problems to the system. This paper focuses on invert-er side current feedback control (invert-er side current feedback, ICF). This paper proposes a method for suppressing resonance of photo-voltaic invert-er clusters based on capacitor voltage feed-forward. First, establish the ICF mathematical model based on HPF and CVF under the weak grid, qualitatively analyze the resonance mechanism of the cluster invert-er, then analyze the system control structure and stability according to the proposed method, and finally verify the effectiveness of the proposed method through simulation and experiment sexuality and correctness.

Towards a new design with generic modeling and adaptive control of a transformable quadrotor

2021 ◽  
pp. 1-31
Author(s):  
S.H. Derrouaoui ◽  
Y. Bouzid ◽  
M. Guiatni
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Experimental Tests ◽  
Generic Model ◽  
System Control ◽  
System A ◽  
Viable Solution ◽  
Generic Modeling ◽  
Adaptive Control Strategy ◽  
The Stability

Abstract Recently, transformable Unmanned Aerial Vehicles (UAVs) have become a subject of great interest in the field of flying systems, due to their maneuverability, agility and morphological capacities. They can be used for specific missions and in more congested spaces. Moreover, this novel class of UAVs is considered as a viable solution for providing flying robots with specific and versatile functionalities. In this paper, we propose (i) a new design of a transformable quadrotor with (ii) generic modeling and (iii) adaptive control strategy. The proposed UAV is able to change its flight configuration by rotating its four arms independently around a central body, thanks to its adaptive geometry. To simplify and lighten the prototype, a simple mechanism with a light mechanical structure is proposed. Since the Center of Gravity (CoG) of the UAV moves according to the desired morphology of the system, a variation of the inertia and the allocation matrix occurs instantly. These dynamics parameters play an important role in the system control and its stability, representing a key difference compared with the classic quadrotor. Thus, a new generic model is developed, taking into account all these variations together with aerodynamic effects. To validate this model and ensure the stability of the designed UAV, an adaptive backstepping control strategy based on the change in the flight configuration is applied. MATLAB simulations are provided to evaluate and illustrate the performance and efficiency of the proposed controller. Finally, some experimental tests are presented.

scholarly journals A Frequency Adaptive Scheme Based on Newton Structure of PRRC for LCL-Type Inverter Connected with Weak Grid

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4225
Author(s):  
Chengbi Zeng ◽  
Sudan Li ◽  
Hanwen Wang ◽  
Hong Miao
Keyword(s):  
Repetitive Control ◽  
Harmonic Distortion ◽  
Adaptive Scheme ◽  
Computational Burden ◽  
Weak Grid ◽  
Control Scheme ◽  
Sample Frequency ◽  
Fractional Delay ◽  
Pr Controller ◽  
Online Tuning

Repetitive control (RC) is gradually used in inverters tied with weak grid. To achieve the zero steady-state error tracking of inverter current and compensate the harmonic distortion caused by frequency fluctuation, a frequency adaptive (FA) control scheme for LCL-type inverter connected with weak grid is proposed. This scheme adopts a proportional resonance (PR) controller in parallel with RC (PRRC) to overcome the disadvantages caused by RC inherent one-cycle time delay. A fractional delay (FD) filter based on the Newton structure is proposed to approximate the fraction item of fs/f, where fs and f are sample frequency and grid frequency, respectively. The structure of the proposed FD filter is relatively simple; moreover, coefficients of the filter maintain constant so as not to need online tuning even when grid frequency fluctuates, which decreases the computational burden considerably. The feasibility and effectiveness of the proposed FA control scheme, named as Newton-FAPRRC, are all verified by the simulation and experimental results.

scholarly journals A novel current controller design for grid-integrated PV inverter system

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Ayaz Ahmad ◽  
L. Rajaji ◽  
A. Iqbal
Keyword(s):  
Controller Design ◽  
Vital Role ◽  
Current Feedback ◽  
Lcl Filter ◽  
Design Algorithm ◽  
Grid Voltage ◽  
Pv Inverter ◽  
Current Controller ◽  
Experimental Implementation ◽  
Grid Connected Inverter

AbstractDistributed generators are playing a vital role in supporting the grid in ever-increasing energy demands. Grid code regulation must be followed when integrating the photovoltaic inverter system to the grid. The paper investigates and analyzes a controller model for grid-connected PV inverters to inject sinusoidal current to the grid with minimum distortion. To achieve better tracking and disturbance rejection, a DSP-based current controller is designed with LCL filter. The controller gets the current feedback from the grid, compares it with reference current, and calculates duty cycle to generate PWM pulses to trigger H-bridge converters. The grid voltage is loaded to the initial value in proposed PR controller to ensure the initial inverter voltage to match the grid voltage. The paper presents a novel current controller algorithm for grid-connected inverter system, and simulation is done. A detailed analysis has been carried out to validate the proposed design algorithm. Experimental implementation of the current controller in the DC/AC converter circuits with an LCL filter is done for 5.4 kW to validate and match the simulation model.

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