Coordination Control Strategy for Active and Reactive Power of DFIG Based on Exact Feedback Linearization under Grid Fault Condition

2011 ◽  
Vol 48-49 ◽  
pp. 335-344
Author(s):  
Meng Zeng Cheng ◽  
Zhen Lan Dou ◽  
Xu Cai
Keyword(s):  
Nonlinear Control ◽  
Power System ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Transient Stability ◽  
Reactive Power ◽  
Control Method ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Nonlinear Control Method

In this paper, a control strategy for operation of rotor side converter (RSC) of Doubly Fed Induction Generators (DFIG) is developed by injecting reactive power into the grid in order to support the grid voltage during and after grid fault events. The novel nonlinear control method is based on differential geometry theory, and exact feedback linearization is applied for control system design of DFIG. Then the optimal control for the linearized system is obtained through introducing the linear quadratic regulator (LQR) design method. Simulation results on a single machine infinite bus power system show that the proposed nonlinear control method can inject reactive power to fault grid rapidly, reduce the oscillation of active power and improve the transient stability of power system.

scholarly journals Research on Control Methods for the Pressure Continuous Regulation Electrohydraulic Proportional Axial Piston Pump of an Aircraft Hydraulic System

2019 ◽  
Vol 9 (7) ◽  
pp. 1376
Author(s):  
Peng Zhang ◽  
Yunhua Li
Keyword(s):  
Feedback Linearization ◽  
Control Method ◽  
Linear Quadratic Regulator ◽  
Piston Pump ◽  
Control Methods ◽  
Hydraulic Systems ◽  
Axial Piston Pump ◽  
Linear Quadratic ◽  
Delivery Pressure ◽  
Axial Piston

The objective of this paper is to design a pump that can match its delivery pressure to the aircraft load. Axial piston pumps used in airborne hydraulic systems are required to work in a constant pressure mode setting based on the highest pressure required by the aircraft load. However, the time using the highest pressure working mode is very short, which leads to a lot of overflow lose. This study is motivated by this fact. Pressure continuous regulation electrohydraulic proportional axial piston pump is realized by combining a dual-pressure piston pump with electro-hydraulic proportional technology, realizing the match between the delivery pressure of the pump and the aircraft load. The mathematical model is established and its dynamic characteristics are analyzed. The control methods such as a proportional integral derivative (PID) control method, linear quadratic regulator (LQR) based on a feedback linearization method and a backstepping sliding control method are designed for this nonlinear system. It can be seen from the result of simulation experiments that the requirements of pressure control with a pump are reached and the capacity of resisting disturbance of the system is strong.

scholarly journals An Enhanced Control Strategy for Mitigation of State-Transition Oscillation Phenomena in Grid-Forming Self-Synchronized Converter System with Islanded Power System

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8453
Author(s):  
Ki Ryong Kim ◽  
Sangjung Lee ◽  
Jong-Pil Lee ◽  
Jaesik Kang
Keyword(s):  
Power System ◽  
Control Strategy ◽  
State Transition ◽  
Reactive Power ◽  
Phase Synchronization ◽  
Control Method ◽  
System Stability ◽  
Electromagnetic Transient ◽  
Point Of Common Coupling ◽  
Hardware In Loop

This paper proposes an enhanced control strategy for mitigating state-transition oscillations in active and reactive power responses of self-synchronized converter system to secure the islanded power system stability. The self-synchronized converter is well known for “grid-forming” that is able to operate to stand-alone mode (SAM) providing grid voltage and frequency without phase synchronization units. Although the grid-forming (GFM) is self-synchronized, the inherent synchronization principle causes system degradation in which should maintain a point of common coupling (PCC) voltage for critical loads as well as transitions from grid-connected mode (GCM) to SAM and vice versa. Therefore, this paper focuses on resolving the inherent oscillatory issues in GFM self-synchronized converter system (especially adopted ‘synchronverter’ principle), and proposes a control strategy for controllability improvement based on stability analysis for smooth state-transition under islanded power system. The efficacy of the proposed control method is verified through a high-fidelity electromagnetic transient (EMT) simulation with case studies on 30kW synchronverter system and further experimental hardware-in-loop system (HILS) test with Opal-RT (OP-5707) platform.

Study on Improvement Transient Stability of the Large-Scale Wind Farms Integration with STATCOM

2013 ◽  
Vol 385-386 ◽  
pp. 1082-1085 ◽  
Author(s):  
Yan Juan Wu ◽  
Lin Chuan Li ◽  
Fang Zhang
Keyword(s):  
Power System ◽  
Control Strategy ◽  
Large Scale ◽  
Transient Stability ◽  
Reactive Power ◽  
Wind Farms ◽  
Double Loop ◽  
Loop Control ◽  
Simulation Results

In view of a serious threat for the transient stability of the power system being caused by the large-scale wind farms integration, and combining with advantages of STATCOM which can quickly restore the fault voltage and fastly, flexibly and smoothly compensate the reactive power, a method is proposed using STATCOM controller of to improve transient stability of the power system integrated by large-scale wind farms. The control strategy of the STATCOM controller uses adaptive double loop control. The role of the device to improvement transient stability of the power system is studied under the condition of serious fault. by simulation comparison with the condition without STATCOM controller installed at the same place. The simulation results show that the STATCOM controller can clearly improve transient stability of the power system integrated by large-scale wind farms.

scholarly journals Transient Stability Enhancement of a Grid-Connected Large-Scale PV System Using Fuzzy Logic Controller

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2437
Author(s):  
Md. Rifat Hazari ◽  
Effat Jahan ◽  
Mohammad Abdul Mannan ◽  
Narottam Das
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Control Strategy ◽  
Computer Aided Design ◽  
Large Scale ◽  
Transient Stability ◽  
Fuzzy Logic Controller ◽  
Reactive Power ◽  
Low Voltage ◽  
Pv System

This paper presents a new intelligent control strategy to augment the low-voltage ride-through (LVRT) potential of photovoltaic (PV) plants, and the transient stability of a complete grid system. Modern grid codes demand that a PV plant should be connected to the main power system during network disturbance, providing voltage support. Therefore, in this paper, a novel fuzzy logic controller (FLC) using the controlled cascaded strategy is proposed for the grid side converter (GSC) of a PV plant to guarantee voltage recovery. The proposed FLC offers variable gains based upon the system requirements, which can inject a useful amount of reactive power after a severe network disturbance. Therefore, the terminal voltage dip will be low, restoring its pre-fault value and resuming its operation quickly. To make it realistic, the PV system is linked to the well-known IEEE nine bus system. Comparative analysis is shown—using power system computer-aided design/electromagnetic transients including DC (PSCAD/EMTDC) software—between the conventional proportional–integral (PI) controller-based cascaded strategy and the proposed control strategy to authenticate the usefulness of the proposed strategy. The comparative simulation results indicate that the transient stability and the LVRT capability of a grid-tied PV system can be augmented against severe fault using the proposed FLC-based cascaded GSC controller.

Engagement Control of Automated Clutch for Vehicle Launching Considering the Instantaneous Changes of Driver's Intention

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Liang Li ◽  
Zaobei Zhu ◽  
Yong Chen ◽  
Kai He ◽  
Xujian Li ◽  
...  
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Sliding Mode ◽  
Linear Quadratic Regulator ◽  
Vehicle Speed ◽  
Linear Quadratic ◽  
Clutch Engagement ◽  
Automated Manual Transmission ◽  
Driver’S Intention ◽  
Artificial Neural Network Ann

Engagement control of automated clutch is essential during launching process for a vehicle equipped with an automated manual transmission (AMT), and instantaneous changes in the driver's launching intention make it more complicated to control the clutch. This paper studies the identification of the driver's launching intentions, which may change anytime, and proposes a clutch engagement control method for vehicle launching. First, a launching-intention-aware machine (LIAM) based on artificial neural network (ANN) is designed for real-time tracking and identifying the driver's launching intentions. Second, the optimal engagement strategy for different launching intentions is deduced based on the linear quadratic regulator (LQR), which figures out a compromise between friction loss, vehicle shock, engine speed, clutch speed, and desired vehicle speed. Third, the relationship between transmitted torque and clutch position is obtained by experiments, and a sliding-mode controller (SMC) is designed for clutch engagement. Finally, the clutch engagement control strategy is validated by a joint simulation model and an experiment bench. The results show that the control strategy reflects the driver's launching intentions correctly and improves the performance of vehicle launching.

scholarly journals A Model Predictive Water-Level Difference Control Method for Automatic Control of Irrigation Canals

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 762 ◽  
Author(s):  
Kong ◽  
Lei ◽  
Wang ◽  
Long ◽  
Lu ◽  
...  
Keyword(s):  
Automatic Control ◽  
Water Level ◽  
Control Strategy ◽  
Control Method ◽  
Linear Quadratic Regulator ◽  
Automatic Regulation ◽  
Irrigation Canal ◽  
Linear Quadratic ◽  
Lqr Control ◽  
Level Difference

In this paper, automatic control of the water level in an irrigation canal by automatic regulation of intermediate gates was studied. Previous scholars have proposed a water level difference control strategy that works to keep relative deviations in all pools the same for a particular situation where the operator does not have full control over the canal inflow, with the centralized linear quadratic regulator (LQR) control method used. While in practice, the deviation tolerance of pools may differ in some canals which limits the applicability of the control strategy. In this work, a weight coefficient was added to the deviation and the algorithm was improved to keep the relative deviations to certain proportions. The model predictive control (MPC) method was then used with this improved control strategy and was compared to the LQR control method using the same control strategy. The results showed that the improved strategy can keep the water level deviations in all pools to certain proportions, as is our objective. Also, under this difference control strategy, the MPC method greatly improved the control performance compared to the LQR control method.

BACKSTEPPING CONTROL STRATEGY FOR AN UNDERACTUATED X4-AUV

2015 ◽  
Vol 74 (9) ◽  
Author(s):  
Zainah Md. Zain ◽  
Nur Fadzillah Harun
Keyword(s):  
Nonlinear Control ◽  
Lyapunov Stability ◽  
Control Strategy ◽  
Stability Theory ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Lyapunov Stability Theory ◽  
Backstepping Control ◽  
Six Degrees Of Freedom ◽  
Nonlinear Control Method

A nonlinear control method is considered for stabilizing all attitudes and positions (x, y or z) of an underactuated X4-AUV with four thrusters and six degrees-of-freedom (DOFs), in which the positions are stabilized according to the Lyapunov stability theory and angles are stabilized using backstepping control method. A dynamical model is first derived, and then a sequential nonlinear control strategy is implemented for the X4-AUV, composed of translational and rotational subsystems. A controller for the translational subsystem stabilizes one position out of x-, y-, and z-coordinates, whereas controllers for the rotational subsystems generate the desired roll, pitch and yaw angles. Thus, the rotational controllers stabilize all the attitudes of the X4-AUV at a desired (x-, y- or z-) position of the vehicle. Some numerical simulations are conducted to demonstrate the effectiveness of the proposed controllers.

Research of the Wind Power’s Transient Stability

2012 ◽  
Vol 229-231 ◽  
pp. 1043-1046 ◽  
Author(s):  
Yuan Zhou ◽  
Zhi Jie Wang ◽  
San Ming Liu ◽  
Xia Sun
Keyword(s):  
Mathematical Model ◽  
Power System ◽  
Wind Power ◽  
Control Strategy ◽  
Transient Stability ◽  
Reactive Power ◽  
Active Power ◽  
Wind Power System

The purpose of this paper is to improve the transient stability of wind power system. This paper presents a new DFIG control strategy, The strategy achieve the decoupling of reactive power and active power. In order to improve the transient stability of wind power, here lead STATCOM into wind power system. Then put forward the STATCOM'S control strategy according it's mathematical model. The simulation result shows that, the proposed scheme can greatly improve the wind power system's transient stability.

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