Equivalent Input Disturbance-Based Control Design for Three Phase Dual-Stage Grid-Tied Photovoltaic System Considering Dead Time Effect

Grid-tied inverter is the prominent component of the three-phase dual-stage photovoltaic (PV) grid-tied power generation system. However, the disturbances caused by dead time effect will pose the reduction of grid-tied current quality and even cause the imbalance of inverter itself or other circuit devices. In this paper, a current control strategy is proposed to damp dead time effect for the three-phase dual-stage PV grid-tied inverter system, and its design, stability analysis, and implementation are carried out. First, the inverter model is modified by regarding the dq reference frame coupling terms, uncertainties, and external and internal disturbances as an unknown lumped disturbance. Then, a current control scheme based on compensation of equivalent input disturbance is introduced, and it estimates and compensates the unknown lumped disturbance, which effectively realizes the inverter model decoupling and comprehensive disturbance rejection. Last, simulation results demonstrate the effectiveness and superiority of the proposed current controller.

TRACKING CONTROL OF WHEELED MOBILE ROBOT WITH MODEL UNCERTAINTIES AND INPUT DISTURBANCE: A NOVEL APPROACH WITH DISTURBANCE ESTIMATION AND ARBITRARY CONVERGENCE TIME CONTROLLER

Xe tự hành đã được sử dụng rộng rãi trong thực tế và chúng thu hút được nhiều sự quan tâm từ những nhà nghiên cứu do tính ràng buộc không tích phân được, tính phi tuyến và tải bất định của chúng. Trong bài báo này một phương pháp điều khiển bám mới được đề xuất cho xe tự hành với mô hình bất định và có nhiễu đầu vào. Phương pháp mới này dựa trên một bộ quan sát nhiễu đầu vào và bộ điều khiển có thời gian đáp ứng tùy ý. Bất định của mô hình và nhiễu đầu vào sẽ được bù bằng bộ quan sát nhiễu trong khi đó sai lệch tốc độ sẽ tiến đến không trong một khoảng thời gian xác lập cho trước bởi bộ điều khiển thời gian hữu hạn tùy ý, bộ điều khiển này sẽ cải thiện chất lượng điều khiển của hệ kín. Tính hiệu quả của phương pháp được kiểm chứng thông qua mô phỏng số.

Arm Angle Tracking Control with Pole Balancing Using Equivalent Input Disturbance Rejection for a Rotational Inverted Pendulum

This paper proposes a robust tracking control method for swing-up and stabilization of a rotational inverted pendulum system by applying equivalent input disturbance (EID) rejection. The mathematical model of the system was developed by using a Lagrangian equation. Then, the EID, including external disturbances and parameter uncertainties, was defined; and the EID observer was designed to estimate EID using the state observer dynamics and a low-pass filter. For robustness, the linear-quadratic regulator method is used with EID rejection. The closed-loop stability is proven herein using the Lyapunov theory and input-to-state stability. The performance of the proposed method is validated and verified via experimental results.

An Improved Equivalent-Input-Disturbance Method for Uncertain Networked Control Systems with Packet Losses and Exogenous Disturbances

In a networked control system (NCS), time delays, uncertainties, packet losses, and exogenous disturbances seriously affect the control performance. To solve these problems, a modified disturbance suppression configuration of NCS was built. In the configuration, a proportional–integral observer (PIO) reproduces the state of a plant and reduces the observation error; an equivalent input disturbance (EID) estimator estimates and compensates for the disturbance in the control input channel. The stability conditions of the NCS are given by using a linear matrix inequality, and the gains of the PIO and state feedback controller are obtained. Numerical simulation results and an application of a magnetic levitation ball system verifies the effectiveness of the presented method. Comparison with the conventional PIO and EID methods shows that the presented method reduced the tracking error to about one-fifth and two-thirds of their original values, respectively. This demonstrates the validity and superiority of the presented method.

Fault-Tolerant Tracking Control for a Descriptor System under an Unknown Input Disturbances

The paper proposes a fault-tolerant tracking control scheme based on a robust observer for a descriptor system. Thus, it is assumed that the described system can be simultaneously occupied by an unknown input disturbance, along with an actuator and sensor faults. Additionally, it is natural to assume that the unknown input disturbance cannot be estimated, which makes the control process more difficult. Moreover, the proposed descriptor system is also occupied by external disturbances. Thus, the robust stability of the proposed control and estimation scheme was guaranteed by using H∞ performance. Consequently, the DC servo-motor laboratory system was used to confirm the correctness and effectiveness of the proposed fault-tolerant tracking control scheme.