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.

scholarly journals Efficient Control of a Three Phase Grid Connected PV System

2021 ◽  
Vol 297 ◽  
pp. 01012
Author(s):  
Hicham Bahri ◽  
Mohamed Bahri ◽  
Mohamed Aboulfatah ◽  
M’hammed Guisser ◽  
El malah Mohammed ◽  
...  
Keyword(s):  
Control Strategy ◽  
High Efficiency ◽  
Control Strategies ◽  
Dynamic Performance ◽  
Atmospheric Condition ◽  
Photovoltaic System ◽  
Voltage Source ◽  
Good Precision ◽  
Pv System ◽  
Three Phase

This paper presents a new control strategy of a photovoltaic system, which consists of a photovoltaic generator PVG coupled to a three phase load and three phase grid by a three phase voltage source inverter VSI without DC-DC converter. The controller is designed by using Backstepping method based on d-q transformation of a new model of the global system. The main goals of this control strategy are to achieve the maximum power point MPPT with very good precision and the unity power factor in level of the grid power flow. Mathematical analysis demonstrate the asymptotic stability of the controlled system and simulation results proved that the controller has achieved all the objectives with high dynamic performance in presence of atmospheric condition changes. Moreover, the proposed controller shows a very good robustness under system disturbance, which presents the most important advantage of this controller compared to the other control strategies. Furthermore, this controller can operate with a high efficiency with any kind of the load.

scholarly journals New Pulse Width Modulation Technique to Reduce Losses for Three-Phase Photovoltaic Inverters

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mohannad Jabbar Mnati ◽  
Dimitar V. Bozalakov ◽  
Alex Van den Bossche
Keyword(s):  
Control Strategy ◽  
Pulse Width Modulation ◽  
Photovoltaic System ◽  
Pv System ◽  
Total Cost ◽  
Switching Losses ◽  
Three Phase ◽  
Operational Lifetime ◽  
Term Energy ◽  
Dc Bus

Nowadays, most three-phase, “off the shelf” inverters use electrolytic capacitors at the DC bus to provide short term energy storage. However, this has a direct impact on inverter lifetime and the total cost of the photovoltaic system. This article proposes a novel control strategy called a 120° bus clamped PWM (120BCM). The 120BCM modulates the DC bus and uses a smaller DC bus capacitor value, which is typical for film capacitors. Hence, the inverter lifetime can be increased up to the operational lifetime of the photovoltaic panels. Thus, the total cost of ownership of the PV system will decrease significantly. Furthermore, the proposed 120BCM control strategy modulates only one phase current at a time by using only one leg to perform the modulation. As a result, switching losses are significantly reduced. The full system setup is designed and presented in this paper with some practical results.

scholarly journals Comprehensive Power Flow Analyses and Novel Feedforward Coordination Control Strategy for MMC-Based UPFC

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 824 ◽  
Author(s):  
Jinlian Liu ◽  
Zheng Xu ◽  
Liang Xiao
Keyword(s):  
Power Systems ◽  
Control Strategy ◽  
Computer Aided Design ◽  
Power Flow ◽  
Feedforward Control ◽  
Control Strategies ◽  
Dynamic Performance ◽  
Unified Power Flow Controller ◽  
3 Dimensional ◽  
Steady State Operation

This paper aims to discover the general steady-state operation characteristics, as well as improving the dynamic performance, of the modular multilevel converter (MMC)-based unified power flow controller (UPFC). To achieve this, first, we established a detailed power flow model for MMC-based UPFC containing each critical part and made qualitative and graphical analyses combining 2-dimensional operation planes and 3-dimensional spatial curve surfaces comprehensively to derive general power flow principles and offer necessary references for regulating UPFC. Furthermore, to achieve better performance, we designed a feedforward control strategy for the shunt and series converters of UPFC, both comprising two feedforward control blocks with the introduction of necessary compensating branches, and analyzed the performance in complex and time domain, respectively. The proposed power flow principles and control strategies were validated by a (power systems computer aided design) PSCAD model of 220 kV double-end system; the results reveal the MMC-based UPFC can realize the power flow principles and improve the control speed, stability, and precision of the power flow regulations under various conditions.

scholarly journals Study on High Performance Control of the Machine-Side Converter of Doubly-Fed Turbines under Grid Distortion

2020 ◽  
Vol 185 ◽  
pp. 01060
Author(s):  
Huanruo Qi ◽  
Ningkang Zheng ◽  
Xiangyang Yan ◽  
Yilong Kang
Keyword(s):  
Reference Frame ◽  
Control Strategy ◽  
High Performance ◽  
Control Strategies ◽  
Dynamic Modelling ◽  
Performance Control ◽  
Advantages And Disadvantages ◽  
Current Controller ◽  
Simulation Results ◽  
Doubly Fed

Two control strategies of DFIG under grid distortion are firstly summarized, namely, the control strategy of PI-R current controller based on dq reference frame and the control strategy of PI current controller based on the multiple rotating dq reference frame, and their advantages and disadvantages are analysed. On the basis of dynamic modelling of DFIG under grid distortion, in view of the defect that DFIG coupling is not considered in the control strategy of PI-R current controller based on dq reference frame, an improved control strategy considering motor coupling is proposed. In the end, the modelling and simulation of the unimproved and improved control strategies of PI-R current controller based on dq reference frame are carried out, and the simulation results verified the effectiveness of the improved control strategy.

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.

Study Performance of Pure Electric Buses Based on the Fuzzy Control Strategy

2011 ◽  
Vol 301-303 ◽  
pp. 1482-1488
Author(s):  
Feng Jun Zhou ◽  
Cheng Lin ◽  
Jin Rui Nan ◽  
Gang Wang ◽  
Wan Ke Cao
Keyword(s):  
Fuzzy Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Dynamic Performance ◽  
Excellent Performance ◽  
Driving System ◽  
Electric Bus ◽  
Fuzzy Control Strategy ◽  
Study Performance

Pure electric bus control strategies and methods have an important effect on performance of the bus. The pure electric buses vehicle driving system was modeled and optimized by the fuzzy control strategy. Through simulation and commissioning tests, both the dynamic performance and economy of the pure electrical bus that using fuzzy control strategy have an excellent performance.

Some Controlling Strategies of DFIG to the Grid Turbulence

2013 ◽  
Vol 291-294 ◽  
pp. 541-543
Author(s):  
Huan Wang ◽  
Lei Pan
Keyword(s):  
Control Strategy ◽  
Tracking Control ◽  
Dynamic Performance ◽  
Synchronous Generator ◽  
Active Power ◽  
Current Control ◽  
Grid Turbulence ◽  
Dynamic Adjustment ◽  
Stator Current ◽  
Speed Fluctuation

The paper introduces several methods about controlling strategies of DFIG to the gird turbulence. They could reduce the torque pulsation. They have better dynamic adjustment performance than the positive, negative sequence dual current control strategy. Stator current THD is well controlled. The experimental results show that it can smooth the DFIG active power output comparing with the traditional maximum wind energy tracking control strategy, significantly reduces the speed fluctuation of synchronous generator. The dynamic performance is improved.

scholarly journals Fractional-Order Control of Grid-Connected Photovoltaic System Based on Synergetic and Sliding Mode Controllers

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 510
Author(s):  
Marcel Nicola ◽  
Claudiu-Ionel Nicola
Keyword(s):  
Control System ◽  
Fractional Order ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Photovoltaic System ◽  
Superior Performance ◽  
Pv System ◽  
Matlab Simulink ◽  
Intermediate Circuit ◽  
The Mathematical Model

Starting with the problem of connecting the photovoltaic (PV) system to the main grid, this article presents the control of a grid-connected PV system using fractional-order (FO) sliding mode control (SMC) and FO-synergetic controllers. The article presents the mathematical model of a PV system connected to the main grid together with the chain of intermediate elements and their control systems. To obtain a control system with superior performance, the robustness and superior performance of an SMC-type controller for the control of the udc voltage in the DC intermediate circuit are combined with the advantages provided by the flexibility of using synergetic control for the control of currents id and iq. In addition, these control techniques are suitable for the control of nonlinear systems, and it is not necessary to linearize the controlled system around a static operating point; thus, the control system achieved is robust to parametric variations and provides the required static and dynamic performance. Further, by approaching the synthesis of these controllers using the fractional calculus for integration operators and differentiation operators, this article proposes a control system based on an FO-SMC controller combined with FO-synergetic controllers. The validation of the synthesis of the proposed control system is achieved through numerical simulations performed in Matlab/Simulink and by comparing it with a benchmark for the control of a grid-connected PV system implemented in Matlab/Simulink. Superior results of the proposed control system are obtained compared to other types of control algorithms.

Sign in / Sign up

Export Citation Format

Share Document