scholarly journals An Optimal Power Control Strategy for Grid-Following Inverters in a Synchronous Frame

2020 ◽  
Vol 10 (19) ◽  
pp. 6730
Author(s):  
Juan F. Patarroyo-Montenegro ◽  
Jesus D. Vasquez-Plaza ◽  
Fabio Andrade ◽  
Lingling Fan
Keyword(s):  
Power Control ◽  
Transient Response ◽  
Control Strategy ◽  
Linear Quadratic Regulator ◽  
Power Sharing ◽  
Performance Bounds ◽  
Linear Quadratic ◽  
Lcl Filter ◽  
Synchronous Reference Frame ◽  
Power Decoupling

This work proposes a power control strategy based on the linear quadratic regulator with optimal reference tracking (LQR-ORT) for a three-phase inverter-based generator (IBG) using an LCL filter. The use of an LQR-ORT controller increases robustness margins and reduces the quadratic value of the power error and control inputs during transient response. A model in a synchronous reference frame that integrates power sharing and voltage–current (V–I) dynamics is also proposed. This model allows for analyzing closed-loop eigenvalue location and robustness margins. The proposed controller was compared against a classical droop approach using proportional-resonant controllers for the inner loops. Mathematical analysis and hardware-in-the-loop (HIL) experiments under variations in the LCL filter components demonstrate fulfillment of robustness and performance bounds of the LQR-ORT controller. Experimental results demonstrate accuracy of the proposed model and the effectiveness of the LQR-ORT controller in improving transient response, robustness, and power decoupling.

Experimental Investigation of Full-Order Observered and LQR Controlled Building-Like Structure Under Seismic Excitation

2013 ◽  
Vol 307 ◽  
pp. 316-320
Author(s):  
Mustafa Tinkir ◽  
Mete Kalyoncu ◽  
Yusuf Şahin
Keyword(s):  
Control Strategy ◽  
Dynamic Behaviour ◽  
Linear Quadratic Regulator ◽  
Seismic Excitation ◽  
Velocity Control ◽  
Passive Mode ◽  
Linear Quadratic ◽  
Active Mass ◽  
Active Mode ◽  
Two Degree Of Freedom

In this paper, the dynamic behaviour of two degree of freedom building-like structure system against unexpected input such as seismic excitation is considered by experimentally. Proposed system consists of two floors structure with active mass damping (AMD) and shaker. Passive and active mode deflection responses of the floors are investigated and also a cart is used to suppress vibrations, which moves linear direction and is mounted on the second floor. PV (proportional and velocity) control of the cart is realized in passive mode. Moreover LQR (Linear Quadratic Regulator) control is designed to control the cart in active mode while system under excitation. For this aim a full-order observer is designed and implemented to control strategy. Displacements of cart, deflections and accelerations results of the floors are presented separately for passive and active mode responses of the system in the form of graphics.

Vehicle Dynamics Control Based on Linear Quadratic Regulator

2009 ◽  
Vol 16-19 ◽  
pp. 876-880
Author(s):  
Si Qi Zhang ◽  
Tian Xia Zhang ◽  
Shu Wen Zhou
Keyword(s):  
Control Strategy ◽  
Vehicle Dynamics ◽  
Linear Quadratic Regulator ◽  
Active Safety ◽  
Vehicle Stability ◽  
Steering Control ◽  
Linear Quadratic ◽  
Yaw Rate ◽  
Vehicle Dynamics Control ◽  
Yaw Moment

The paper presents a vehicle dynamics control strategy devoted to prevent vehicles from spinning and drifting out. With vehicle dynamics control system, counter braking are applied at individual wheels as needed to generate an additional yaw moment until steering control and vehicle stability were regained. The Linear Quadratic Regulator (LQR) theory was designed to produce demanded yaw moment according to the error between the measured yaw rate and desired yaw rate. The results indicate the proposed system can significantly improve vehicle stability for active safety.

scholarly journals Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5613 ◽  
Author(s):  
Oliver Kalmbach ◽  
Christian Dirscherl ◽  
Christoph M. Hackl
Keyword(s):  
Discrete Time ◽  
Controller Design ◽  
Linear Quadratic Regulator ◽  
Current Control ◽  
Control Loop ◽  
Linear Quadratic ◽  
Lcl Filter ◽  
Current Controller ◽  
Voltage Controller ◽  
Grid Connected Inverter

The paper presents a controller design for grid-connected inverters (GCI) with very small dc-link capacitance that are coupled to the grid via an LCL filter. The usual controller designs would fail and result in instability. The proposed controller has a cascaded structure with a current controller as inner control loop and an outer dc-link voltage controller. The controller design is performed in discrete time and it is based on a detailed stability analysis of the dc-link voltage controller to determine the controller parameters which guarantee stability for all operating points. The inner loop is a state-feedback current controller that is designed based on the discrete linear-quadratic regulator (DLQR) theory. An additional integral error feedback assures steady-state accuracy of the current control loop. The simulation and experimental results validate performance and stability of proposed controller design.

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.

Examination of Different Control Strategies of Heavy-Vehicle Performance

1996 ◽  
Vol 118 (3) ◽  
pp. 489-498 ◽  
Author(s):  
L. Palkovics ◽  
M. El-Gindy
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
Linear Quadratic Regulator ◽  
Torque Control ◽  
Heavy Vehicle ◽  
Vehicle Model ◽  
Linear Quadratic ◽  
Vehicle Performance ◽  
Active Steering ◽  
Handling Characteristics

Heavy vehicles play an economically important role in the transportation process, and their numbers have been increasing for several decades. The active safety of the highway system is an important consideration in the design of a heavy vehicle combination. In this paper, the handling characteristics of a 5-axle tractor-semitrailer is examined and used to test for the desired features of the vehicle’s handling and stability. Using these results the optimal control criterion is derived for the vehicle. Four different control strategies are examined by using the Linear Quadratic Regulator (LQR) approach. These are, active steering of the rear wheels of the tractor; active steering of the wheels of the trailer; active torque control in the fifth-wheel joint; and active yaw torque acting on the tractor. These controllers are designed and examined using a simplified linear vehicle model. In addition to discussing the above-mentioned approaches, this paper discusses a method of modifying the slip angles at the tractor’s rear (driven) axles, however the yaw torque at the tractor cg also can be controlled using what is called “unilateral braking.” As well, the replacement of the active torque control at the fifth wheel joint, by a control strategy based on the usage of controllable dampers at the fifth-wheel joint, will also be examined. In this case, a nonlinear mathematical model of the vehicle is used and a modified control strategy called the RLQR/H∞ approach is used to ensure the vehicle’s performance in the presence of parametric uncertainties. The examination of these control strategies is conducted by using a sophisticated non-linear vehicle model, and the influence of these control strategies on the vehicle’s directional and roll stability during severe path-follow lane-change manoeuvre is discussed.

Optimality of Synergetic Controllers

2006 ◽  
Author(s):  
Antonius Nusawardhana ◽  
Stanislaw H. Zak
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Sliding Mode ◽  
Linear Quadratic Regulator ◽  
Variable Structure ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Control Approach ◽  
Mode Control ◽  
Synergetic Control

Optimality properties of synergetic controllers are analyzed using the Euler-Lagrange conditions and the Hamilton-Jacobi-Bellman equation. First, a synergetic control strategy is compared with the variable structure sliding mode control. The synergetic control design methodology turns out to be closely related to the methods of variable structure sliding mode control. In fact, the method of sliding surface design from the sliding mode control are essential for designing similar manifolds in the synergetic control approach. It is shown that the synergetic control strategy can be derived using tools from the calculus of variations. The synergetic control laws have simple structure because they are derived from the associated first-order differential equation. It is also shown that the synergetic controller for a certain class of linear quadratic optimal control problems has the same structure as the one generated using the linear quadratic regulator (LQR) approach by solving the associated Riccati equation.

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.

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