Compensation Control Structure Research Articles

Joint Control Strategy of Microgrid Inverter Based on Optimal Control and Residual Dynamic Compensation

With the continuous development of microgrid, the inverter under traditional PID control is difficult to meet the power quality requirements of microgrid. In order to improve the anti-interference ability and transient response speed of the output voltage of Isolated AC microgrid inverter, a dynamic compensation control structure combining linear quadratic optimal control and disturbance residual generator is proposed in this paper. Firstly, the quadratic optimal controller is established based on the inverter model. Secondly, the residual generator is established to observe the residual value of the disturbed system. Then, the dynamic compensation controller is designed according to the superposition principle, and a control signal opposite to the influence caused by the disturbance is output at the output of the controller. The disturbance signals can cancel each other without knowing the specific disturbance form. Finally, the experiments of load switching, three-phase imbalance and nonlinear load are designed on MATLAB/Simulink simulation software to verify the effectiveness of the control strategy proposed in this paper.

Neural networks-based adaptive control of uncertain nonlinear systems with unknown input constraints

In this work, we solve the adaptive actuator backlash compensation control problem of uncertain nonlinear systems. A new generalized backlash model is first proposed, which takes both the actuator perturbation and unidentifiable coupling into account, and hence captures the practical backlash behavior more accurately. Nevertheless, such a model makes the adaptive control design difficult, where the most challenging one is that the unrecognizable coupling makes traditional compensation structure no more feasible. To address this issue, we propose an adaptive compensation control structure synthesizing neural networks learning and novel smooth backlash inverse model. With the established compensator and the iterative control design of compensator input, an adaptive neural controller is subsequently proposed to guarantee that all signals of the closed-loop system are bounded, and the tracking error converges to residual of zero asympotically. Simulation results are given to verify the effectiveness of the proposed control scheme.

An Improved Centralized Control Structure for Compensation of Voltage Distortions in Inverter-Based Microgrids

Recently, increased use of non-linear loads has intensified the harmonic distortion and voltage unbalance in distribution systems. Inverter Based Distributed Generators (IBDGs) can be employed as distributed compensators to improve the power quality, as well as to supply distribution systems. In this paper, an enhanced hierarchical control scheme for the compensation of voltage disturbance in an AC Micro Grid (MG) that includes of two control levels is proposed. The secondary control level is performed by a centralized controller. Data of voltage harmonics and voltage unbalance at the MG Sensitive Load Bus (SLB) is sent to the centralized controller by a measurement unit. A general case with a combined voltage harmonic and unbalance distortion is considered. The compensation coefficients for IBDG units are computed by the centralized controller, and reference commands are sent to the local controllers of the IBDG units that act as a primary level of control. In the secondary control level, harmonic analysis is performed for the MG in order to provide a guide for properly assigning the harmonics and unbalance compensation priorities to IBDGs at different locations in the distribution system. Some buses have more participation in exciting the MG resonance modes; therefore, larger harmonic compensation factors are considered for the IBDGs that are near to these buses. For other IBDGs, the voltage unbalance compensation factor is selected bigger. The control system of the IBDGs mainly includes a current controller, a virtual damping resistor loop, and a load compensation block. Effectiveness of the proposed control scheme is demonstrated through simulation studies.

Composite compensation control method for airborne opto-electronic platform mounted on multi-rotor UAV

In order to compensate disturbance and accomplish the stabilized tracking control for airborne platform mounted on multi-rotor unmanned aerial vehicle (MUAV), a self-adjusting tracking control method based on an improved disturbance observer (DOB) and radial basis function (RBF) neural network approximation is proposed. First, a compensated control is introduced into feedback loop in the structure of original disturbance observer, an improved disturbance observer is established based on velocity signals, and the ability of disturbance compensation and robustness are analyzed. Second, aiming at the compensation problem of nonlinear unknown disturbance, a method based on the RBF neural network (RBFNN) approximation properties is utilized. Finally, a composite compensation control structure is designed based on Lyapunov stability theory. The experimental results show that after applying the proposed method, the disturbance of airborne opto-electronic platform is compensated effectively. The proposed method has high precision and stable tracking control performance, and it can fully meet the requirement of airborne opto-electronic platform stability control.

Time Delay Compensation Control Structure for a Robotic Teleoperation System

In this paper, a time delay compensation control structure for a robot teleoperation system is presented. The structure design was made considering 1.9-seconds time delay in the communication between the remote and local stations. The objective is to control both the remote manipulator's position and force. Force and position signals are fedback to the local station so that the human operator feels in his/her hand the force associated with the task being executed at the remote site. Simulations are carried out considering the dynamic model of the hwnan operator in the control loop. In this sense, simulations show a good perfonnance of the proposed compensation control structure.