scholarly journals Research on the Nonlinear Control Strategy of Three-Phase Bridgeless Rectifier under Unbalanced Grids

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3090
Author(s):  
Hong Cheng ◽  
Daokuan Yang ◽  
Cong Wang
Keyword(s):  
Mathematical Model ◽  
Nonlinear Control ◽  
Control Strategy ◽  
Dynamic Performance ◽  
Power Grids ◽  
Current Loop ◽  
State Variables ◽  
Three Phase ◽  
Sequence Components ◽  
Practical Engineering

The three-phase Y-connected bridgeless rectifier is essentially a nonlinear system, and it is difficult to obtain superior dynamic performance under the action of traditional linear controller. Under the condition of unbalanced power grids, this paper has established a mathematical model based on Euler–Lagrange (EL) equations with line voltage and line current as state variables. Furthermore, it then designed a passivity-based controller in inner current loop based on the mathematical model. The hybrid nonlinear control strategy consisting of active disturbance rejection controller (ADRC) in the outer voltage loop and passivity-based controller (PBC) in the inner current loop is adopted to control the system, which does not need to consider the positive and negative sequence components. The control structure is simple and can improve the steady-state accuracy, dynamic performance and anti-interference ability. The feasibility of the proposed control strategy is verified by computer simulation, which has a guiding significance for the application of three-phase bridgeless rectifier in practical engineering.

Mathematical Model of Three-Phase Boost Converter

2012 ◽  
Vol 507 ◽  
pp. 96-100
Author(s):  
Zhong Zhang ◽  
Wei Ming Tong
Keyword(s):  
Mathematical Model ◽  
Nonlinear Control ◽  
Control Strategy ◽  
Boost Converter ◽  
Analysis Method ◽  
Topology Structure ◽  
Conservation Of Energy ◽  
Three Phase ◽  
Converter Topology ◽  
The Mathematical Model

Now the nonlinear control strategy used by a lot of power electronic converters is not dependent on the mathematical model of the system. They are only based on the error of control variables to control the output voltage or other variables, and this leads to the shortcomings of poor control and not easy to optimize. The fundamental reason is that they are not based on the mathematical model of converter topology structure. This paper presents a new way to build mathematical model. The paper established the unified mathematical model of the three-phase Boost converter topology structure by studied the three-phase Boost converter topology structure deeply and based on the law of conservation of energy and combined with small-signal modeling analysis method, and done the systematic analysis for it. The analysis method is also applicable to other converter topology, such as the buck, buck-boost, etc., and the model not only can be used in the controller design, can also provide a theoretical basis for the applications of a new nonlinear control strategy.

The Control Strategy and Simulation of Three-Phase Grid-Connected Photovoltaic System

2012 ◽  
Vol 608-609 ◽  
pp. 164-168
Author(s):  
Jian Jun Su ◽  
Men Yue Hu ◽  
Hong Yan Gong ◽  
Hai Tao Sun ◽  
Zhi Jian Hu ◽  
...  
Keyword(s):  
Control Strategy ◽  
Photovoltaic System ◽  
Current Loop ◽  
Maximum Power Point ◽  
Loop Control ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Three Phase ◽  
Power Point ◽  
Research Situation

Firstly the research situation for grid-connected photovoltaic (PV) is introduced, then, the engineering mathematical model of PV cells is introduced. The perturbation and observation algorithm is chosen as the maximum power point tracking (MPPT) algorithm. The SPWM double-loop control strategy with outer voltage loop and inner current loop is described and a three-phase grid-connected photovoltaic model is established. The simulation results demonstrate the validity and correctness of the simulation model built in this paper.

Asymmetric Voltage Sag Control Strategy for Grid-Connected PV System Based on PIR Controller

2013 ◽  
Vol 724-725 ◽  
pp. 128-131
Author(s):  
Fei Zheng ◽  
Xiao Lin Zhang ◽  
Ming Chang Ding
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Dynamic Performance ◽  
Photovoltaic System ◽  
Voltage Sag ◽  
Dynamic Adjustment ◽  
Pv System ◽  
Current Controller ◽  
Sequence Components ◽  
Fault State

This paper proposes an improved LVRT control strategy based on PIR controller for grid-connected photovoltaic system under asymmetric voltage sag fault. First, the PIR current controller is designed in the positive synchronous frame without the need to decompose the positive and negative sequence components and the dynamic adjustment method for the current-reference calculation is given in order to gain a constant active power. And then, the principle how control strategies switching between the one in normal state and the other one in fault state is revealed in detail. Finally, simulations and experiment test on a 500kVA grid-connected photovoltaic inverter verify that this control strategy achieves good dynamic performance and it improves the PV inverters’ capacity of riding through asymmetric voltage sag fault effectively.

A New Nonlinear Control Strategy for DC/AC Inverter

2012 ◽  
Vol 466-467 ◽  
pp. 829-833 ◽  
Author(s):  
Kun Mu ◽  
Xiao Bin Mu ◽  
Xue Yu Bao
Keyword(s):  
Nonlinear Control ◽  
Control Strategy ◽  
High Performance ◽  
Control Method ◽  
Assembly Language ◽  
Single Chip ◽  
Two Phase ◽  
Three Phase ◽  
Passivity Based Control ◽  
The Mathematical Model

The mathematical model of Three-phase VoltagePulse Width Modulation (PWM) DC/AC inverter is non-linear, in view of the traditional linear control strategy can not meet the requirements of designing high-performance DC/AC inverter, this paper propose a new nonlinear control strategy for Three-phase Voltage PWM DC/AC inverter called Passivity-based Control. We can alter the inverter model in three-phase abc coordinate to two-phase synchronous rotating dq coordinate for establishing the Euler – Lagrange (EL) energy model for this system, then we also proof this system is strictly passive. We can control the output energy of the system, and we use the approaches of injecting damping and decoupling to improve system performance. Usually, we can use Single Chip Microcomputer or other kinds of computer with this algorithm for our design, this algorithm can be programmed with the computer language, such as C/C++ and assembly language, etc. Simulation results show that passivity-based control method can make this system possess the high-performance of robustness and dynamic.

A Study on Nonlinear Decoupling Controller for UPFC

2014 ◽  
Vol 624 ◽  
pp. 460-464
Author(s):  
Zhi Bin Chen ◽  
Yan Ma ◽  
Bo Wen Su
Keyword(s):  
Mathematical Model ◽  
Nonlinear System ◽  
Control Strategy ◽  
Reactive Power ◽  
Dynamic Performance ◽  
Decoupling Control ◽  
Real Power ◽  
Power Decoupling ◽  
Simulation Results ◽  
System Characteristics

In the d-q coordinate system, UPFC mathematical model reveals a nonlinear system with features of a multi-variable, strong coupling, and more interference. In view of these system characteristics, the paper presents a nonlinear overlapping decoupled strategy with better stability and dynamic performance for UPFC control. The control strategy is analyzed and tested with the MATLAB simulative experiments. Simulation results show that the proposed control strategy can quickly and accurately respond to the needs of the power system, and realize real power and reactive power decoupling control effectively. Keywords: Dynamic Modeling, Nonlinear, Decoupling Controller, UPFC, MATLAB

Small-Signal Equivalent Circuit Modeling and Controller Design of DC/DC Converter Based on Matlab

2014 ◽  
Vol 1070-1072 ◽  
pp. 1586-1591
Author(s):  
Xiao Long Xiao ◽  
Xiao Jun Lu ◽  
Jian Wei Yi ◽  
Xiao Hua Ding
Keyword(s):  
Mathematical Model ◽  
Control Strategy ◽  
Model Building ◽  
Controller Design ◽  
Dynamic Performance ◽  
Feedback System ◽  
Small Signal ◽  
Loop Feedback ◽  
And Control ◽  
The Mathematical Model

The model-building of DC/DC converter is the key to design the control of system. It is important to study DC/DC converter stability and dynamic performance. A small-signal model of buck/boost circuit was built by average state-space. By analyzing the transfer function of buck/boost circuit, a voltage closed-loop feedback system was designed. Building system of simulation circuit in the Matlab, the result of simulation shows the system has a good static and dynamic performance. It verifies the rationality of the mathematical model and control strategy. It verifies the rationality of the mathematical model and control strategy.

Design and Simulation of the Intelligent Control of the Greenhouse Temperature

2013 ◽  
Vol 423-426 ◽  
pp. 2851-2854
Author(s):  
Lin Zhao
Keyword(s):  
Mathematical Model ◽  
Intelligent Control ◽  
Control Strategy ◽  
Pid Control ◽  
Time Variation ◽  
Performance Index ◽  
Control Method ◽  
Dynamic Performance ◽  
On Line ◽  
Greenhouse Control

In greenhouse control , The production process of the greenhouse environment has many characteristics, such as time variation, nonlinearity and uncertainty. It's very difficult to build an accurate mathematical model. The effect of the conventional control method is not satisfied. Fuzzy control is used to adjust the parameters of PID control on-line in the aspect of control strategy, accordingly it can make static and dynamic performance index more ideal.

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