scholarly journals A NOVEL METHOD FOR DESIGNING THE CONTROLLER OF A LCL-FILTER-BASED GRID-CONNECTED INVERTER WITH CONSIDERING VARYING SYSTEM PARAMETERS

2018 ◽  
Vol 54 (3A) ◽  
pp. 39
Author(s):  
Nguyen Trung Nhan
Keyword(s):  
Controller Design ◽  
Design Method ◽  
Lcl Filter ◽  
Loop Control ◽  
System Parameters ◽  
Three Phase ◽  
Loop Control System ◽  
Novel Method ◽  
Grid Connected Inverter ◽  
The Stability

Exactly determining the control coefficients for the controller of a three-phase LCL-filter-based inverter is an important and challenging issue in microgrid systems. However, existing LCL-filter-based inverter systems usually assume that all system parameters are determined accurately and remain constant over time, which is not true in real situations. Variations in the system parameters are known to possibly seriously degrade the performance of LCL-filter-based inverter systems. For efficiency and robustness, this paper proposes a novel method for the generalized controller design of a three-phase LCL-filter-based grid-connected inverter system that can address deviations in system parameters. An optimum way to determine the stability bounds under various system parameters cases is introduced. The assessment of the stability bounds is based on the Routh criterion by solving the characteristic equation of the closed-loop control system. Simulations results are presented to validate the correctness and effectiveness of the proposed design method.

scholarly journals Research on Discretization PI Control Technology of Single-Phase Grid-Connected Inverter with LCL Filter

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Jianke Li ◽  
Jinquan Wang ◽  
Ye Xu ◽  
Jianting Li ◽  
Jingjing Chen ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
Numerical Algorithms ◽  
Switching Frequency ◽  
Lcl Filter ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Grid Connected Inverter ◽  
The Stability ◽  
The Cost

Compared with L-type filter, LCL-type filter is more suitable for high-power low-switching frequency applications with reducing the inductance, improving dynamic performance. However, the parameter design for the LCL filter is more complex due to the influence of the controller response performance of the converter. If the harmonic current around switching frequency can be fully suppressed, it is possible for inverter to decrease the total inductance as well as the size and the cost. In this paper, the model of the LCL filter is analyzed and numerical algorithms are adopted to analyze the stability of the closed-loop control system and stable regions are deduced with different parameters of LCL filter. Then, the minimum sampling frequencies are deduced with different conditions. Simulation and experimental results are provided to validate the research on the generating mechanism for the unstable region of sampling frequency.

Application of Back-to-Back Circuit in the Intelligent Wheelchair Charging Technology

2014 ◽  
Vol 631-632 ◽  
pp. 654-659
Author(s):  
Li Wang ◽  
Rong Yang ◽  
Xiu Feng Zhang ◽  
Yan Ma
Keyword(s):  
Design Method ◽  
Voltage Source ◽  
Super Capacitor ◽  
Loop Control ◽  
Intelligent Wheelchair ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Pwm Rectifiers ◽  
Bus Voltage ◽  
The Stability

Intelligent wheelchair charging technology put forward a very high request to the stability of the DC bus voltage. This paper describes the three phase principles and topology with Back-to-Back, SVPWM is used to the voltage-source PWM rectifiers, the principle of voltage and current double closed loop control system design the system. According to the principle of super-capacitor store energy for the load and construct their simulation model with SIMULINK. Simulation results demonstrate the feasibility of the above design method.

scholarly journals A Theoretical Concept of Decoupled Current Control Scheme for Grid-Connected Inverter with L-C-L Filter

2021 ◽  
Vol 11 (14) ◽  
pp. 6256
Author(s):  
Mohamad Amin Ghasemi ◽  
Seyed Fariborz Zarei ◽  
Saeed Peyghami ◽  
Frede Blaabjerg
Keyword(s):  
Control Method ◽  
Controller Design ◽  
Current Control ◽  
System Stability ◽  
State Equations ◽  
Lcl Filter ◽  
Control Scheme ◽  
Grid Connected Inverter ◽  
The Stability ◽  
Grid Side

This paper proposes a nonlinear decoupled current control scheme for a grid-connected inverter with LCL filter. Decoupling the active and reactive current control channels is one of the main demands in the control of inverters. For inverters with an L filter, the decoupling can be achieved by a proper feed-forward of grid voltages. However, the coupling of channels is a complex issue for converters with LCL filters. The resonance mode of the LCL filter may cause instability, which adds more complexity to the analysis. In this paper, state equations of the system are provided, which highlight the coupling between active and reactive currents injected into the grid. Accordingly, a non-linear control scheme is proposed which effectively decouples the channels and dampens the resonant modes of the LCL filter. The stability of the proposed control method is verified by the Lyapunov criterion. Independency of the system stability to the grid-impedance is another feature of the proposed approach. Moreover, only grid-side currents are needed for implementation of the proposed scheme, avoiding the need for additional current sensors for the output capacitor and grid-side inductor. For accurate modelling of the inverter, the computation and PWM sampling delays are included in the controller design. Finally, various case studies are provided that verify the performance of the proposed approach and the stability of the system.

Research on Control Strategy for the Three-Phase Grid-Connected Inverter

2012 ◽  
Vol 614-615 ◽  
pp. 1578-1582
Author(s):  
Chun Qing Qi ◽  
Yi Ruan ◽  
Feng Wen Cao
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Response Speed ◽  
Current Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Three Phase ◽  
Control Scheme ◽  
Loop Control System ◽  
Grid Connected Inverter

This paper proposes a control strategy，based on the grid voltage oriented vector control (VOC), which makes three-phase inverter control the active and reactive power of grid-connected inverter under the premise of the direct current control. This paper analyzes the principle of three phase photovoltaic grid connected inverter and describes the control structure of the inverter. The control strategy can overcome the deficiencies of the indirect current control scheme. This paper designs the current closed-loop control system, which not only improve the system dynamic response speed and output current waveform quality, while also reduce its sensitivity to parameter changes to improve the robustness of the system. The simulation results show the validity of control strategy proposed.

scholarly journals Research on LCL-type three-phase photovoltaic grid-connected inverter based on passive damping

2021 ◽  
Vol 2137 (1) ◽  
pp. 012017
Author(s):  
Yifeng Gu ◽  
Xianglian Xu ◽  
Xiaobei Yin ◽  
Yu He
Keyword(s):  
Closed Loop ◽  
Resonance Phenomenon ◽  
Passive Damping ◽  
Working Process ◽  
Lcl Filter ◽  
Loop Control ◽  
Simulink Simulation ◽  
Three Phase ◽  
Before And After ◽  
Grid Connected Inverter

Abstract The traditional LCL filter has resonance phenomenon in the working process of three-phase photovoltaic grid-connected inverter system. Based on the analysis of the frequency characteristics of LCL filter equivalent circuit before and after the introduction of passive damping resistor, it is concluded that the resonance of the system can be suppressed after the introduction of passive damping resistor. In the meantime, the current double closed-loop control strategy used in the system is introduced in detail. Finally, the simulation model is built by Matlab/Simulink simulation platform to verify the feasibility of the research method of LCL-type three-phase photovoltaic grid-connected inverter based on passive damping.

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.

scholarly journals Actuator Saturated Fuzzy Controller Design for Interval Type-2 Takagi-Sugeno Fuzzy Models with Multiplicative Noises

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 823
Author(s):  
Wen-Jer Chang ◽  
Yu-Wei Lin ◽  
Yann-Horng Lin ◽  
Chin-Lin Pen ◽  
Ming-Hsuan Tsai
Keyword(s):  
Nonlinear Systems ◽  
Fuzzy Controller ◽  
Controller Design ◽  
Actuator Saturation ◽  
Design Method ◽  
Fuzzy Model ◽  
The Stability ◽  
Interval Type ◽  
Takagi Sugeno

In many practical systems, stochastic behaviors usually occur and need to be considered in the controller design. To ensure the system performance under the effect of stochastic behaviors, the controller may become bigger even beyond the capacity of practical applications. Therefore, the actuator saturation problem also must be considered in the controller design. The type-2 Takagi-Sugeno (T-S) fuzzy model can describe the parameter uncertainties more completely than the type-1 T-S fuzzy model for a class of nonlinear systems. A fuzzy controller design method is proposed in this paper based on the Interval Type-2 (IT2) T-S fuzzy model for stochastic nonlinear systems subject to actuator saturation. The stability analysis and some corresponding sufficient conditions for the IT2 T-S fuzzy model are developed using Lyapunov theory. Via transferring the stability and control problem into Linear Matrix Inequality (LMI) problem, the proposed fuzzy control problem can be solved by the convex optimization algorithm. Finally, a nonlinear ship steering system is considered in the simulations to verify the feasibility and efficiency of the proposed fuzzy controller design method.

The Design and Simulation of Three-Phase PWM Converter

2013 ◽  
Vol 321-324 ◽  
pp. 917-920
Author(s):  
Guang Ya Liu ◽  
Xiao Song Li
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Voltage Source ◽  
Pwm Rectifier ◽  
Phase Voltage ◽  
Pwm Converter ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Three Phase ◽  
Loop Control System

Three-phase voltage source PWM rectifier generally adopts double closed loop control system. According to the high frequency characteristic of three-phase voltage source PWM rectifier, this paper put forward the setting method of current inner ring regulator and voltage outer ring regulator PI parameter. Finally, it is verified by simulation.

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