An advanced beam energy control strategy for medical cyclotron via ADRC with model-based feedforward controller.

In order to solve the problem of insufficient control performance of various traditional control strategies in the complex environment of grid-connected inverters, the active disturbance rejection control (ADRC) strategy based on the virtual synchronous generator (VSG) is proposed. The mathematical model of a grid-connected photovoltaic inverter based on the VSG is built. The proposed control strategy provides the inverter with more disturbance attenuation and provides rotational inertia. The control strategy estimates and compensates the total disturbance and generates the reference active power and reactive power by ADRC. The control strategy converts the three-phase voltage and current outputs into positive and negative sequences on the dq reference frame. The VSG control module generates a reference voltage command and outputs it to the dual closed loop PI feedforward decoupling control. The PWM signal is finally obtained by the PI feedforward decoupling control. The ADRC strategy based on the VSG does not change the original control characteristics of the VSG; it retains the characteristics of the synchronous generator, and it also provides inertia and damping for the power grid. The simulation shows that the ADRC strategy based on the VSG applied to the inverter can attenuate disturbances. Under the unfavorable conditions of the unstable reference power, such as the unbalanced three-phase voltage and the random disturbance, the output power matches the international electricity standard.

This paper proposes a new type of damped multi-mode switching damper based on a high-speed switching solenoid valve. The structural design of the damper is completed, and its working principle of realizing different damping modes is analyzed. A damping characteristic model of the damper is constructed, and the change rule of the damping characteristic of the multi-mode switching damper is analyzed. The seat suspension of a wheel loader is equipped with a damper that is controlled by a damping strategy. A 10-degree-of-freedom mixed-logic dynamic model of the seat suspension system is established using HYSDEL, and a multi-mode switching damper is employed. The weight coefficients are adjusted using a self-immunity control strategy, and the hybrid model predictive control method is used to complete the damping control strategy. Simulation results show that, compared with the fuzzy control strategy, the designed wheel loader seat suspension damping active disturbance rejection control (ADRC) strategy not only effectively reduces the root-mean-square (RMS) value of the driver’s vertical vibration acceleration up to more than 40% at different speeds and shock conditions, but also effectively reduces the driver’s vertical vibration acceleration. The ADRC strategy is a robust approach that achieves the desired control objective of the system.

In order to improve the dynamic tracking speed and anti-disturbance ability of active power filter (APF) to harmonic current, an improved backstepping active disturbance rejection control (ADRC) strategy is proposed in this paper. An improved linear extended state observer (LESO) is established by exploring the principle of deviation adjustment to ensure that the total disturbance can be estimated in a relatively timely and accurately manner. In addition, based on the idea of backstepping design and the Lyapunov function design control law, a compound control strategy combining backstepping method and ADRC is proposed to improve the control precision and dynamic response speed of the system. In addition, the stability of the proposed control strategy is analyzed. Finally, the effectiveness and superiority of the proposed control strategy are verified by comparative simulation.

To solve the problems of complicated parameter setting and poor anti-disturbance in the droop control of traditional DC microgrid, a distributed dual-loop active disturbance rejection control (ADRC) strategy for a DC microgrid is proposed. Compared with the existing traditional droop control, the ADRC strategy has strong anti-disturbance ability, which can effectively suppress the parameter fluctuation and the uncertain disturbance in the power grid. In this paper, a simulation model is built in Matlab/Simulink and the simulation results show that when disturbance occurs, the control strategy can effectively adjust the power balance in DC microgrid to ensure a constant bus voltage. Compared with the traditional PI control method, the proposed method can reduce the voltage fluctuation and improve the anti-disturbance ability of the DC microgrid.

Active disturbance rejection control strategy applied to cathode humidity control in PEMFC system

The PID control strategy is usually used to control the motor in the electric servo loading system CESLS), however there are some nonlinear factors such as mechanism clearance and surplus torque in the loading process, the conventional PID control method can't guarantee the control performance and the loading accuracy of the ESLS. A position feed-forward compensation controller is introduced in the ESLS, and an outer loop active disturbance rejection control (ADRC) strategy is designed to eliminate position disturbance and surplus torque disturbance in this paper. The method of “observation + compensation” used in the outer loop ADRC controller is not only to suppress the surplus torque, but also to improve the steady-state performance of the ESLS. The simulation result shows that the electric servo loading system based on ADRC strategy can effectively improve the tracking accuracy of the ESLS and enhance the stability of the ESLS.

Due to the characteristics of predictability and high energy density in tidal current resources, tidal stream turbine generation systems have been developed in the last decades around the world. Speed control would be necessary to perform the maximum power point tracking (MPPT) task under varying marine current conditions. Considering that various disturbances or parameter uncertainties may deteriorate the system performance, the active disturbance rejection control (ADRC) strategy seems to be an interesting solution for controller designs. In this paper, an ADRC strategy is applied in the speed control loop for realizing MPPT under disturbances of current velocity and turbine torque. The system performance of the proposed ADRC is compared with PI and high-order sliding mode (HOSM) control strategies. The operation under swell wave disturbance is also carried out. This simulation-based comparative study shows the effectiveness and advantages of the ADRC controller over conventional PI controller in terms of quick convergence, overshoots elimination, and better performance under disturbances.

This paper proposes an Active Disturbance Rejection Control (ADRC) strategy applied to synthesize the controllers of the DFIG-based Wind Energy Conversion System (WECS) connected to a utility grid under normal conditions. These controllers drive WECS to inject its maximum power into the utility grid (by MPPT control) for lower wind speeds, and to limit this production at its nominal power for strong winds by controlling the pitch angle. ADRC is one of the algorithms that estimate and cancel, in real time, external and internal disturbances. Its design does not require an accurate system model of the system under control; a discussion on its structure and its principle is conducted. Simulation analyses of the proposed scheme to manage the presented WECS are performed in the MATLAB-Simulink environment. These simulation results will be compared to the ones when the command is based on classic PI controllers and also to the experimental results performed on a wind emulator. The obtained results demonstrate the superiority and the effectiveness of the proposed control strategy and approach.

A novel and robust active disturbance rejection control (ADRC) strategy for variable speed wind turbine systems using a doubly fed induction generator (DFIG) is presented in this paper. The DFIG is directly connected to the main utility grid by stator, and its rotor is connected through a back-to-back three phase power converter (AC/DC/AC). Due to the acoustic nature of wind and to ensure capturing maximum energy, a control strategy to extract the available maximum power from the wind turbine by using a maximum power point tracking (MPPT) algorithm is presented. Moreover, a pitch actuator system is used to control the blades’ pitch angle of the wind turbine in order to not exceed the wind turbine rated power value in case of strong wind speeds. Furthermore, the rotor-side converter is used to control the active and reactive powers generated by the DFIG. However, the grid-side converter is used to control the currents injected into the utility grid as well as to regulate the DC-link voltage. This paper aims to study and develop two control strategies for wind turbine system control: classical control by proportional integral (PI) and the proposed linear active disturbance rejection control (LADRC). The main purpose here is to compare and evaluate the dynamical performances and sensitivity of these controllers to the DFIG parameter variation. Therefore, a series of simulations were carried out in the MATLAB/Simulink environment, and the obtained results have shown the effectiveness of the proposed strategy in terms of efficiency, rapidity, and robustness to internal and external disturbances.

PurposeThis paper aims to improve the anti-interference ability of the airborne radar stabilization platform, especially the ability to suppress continuous disturbance under complex air conditions to ensure the clarity and stability of airborne radar imaging.Design/methodology/approachThis paper proposes a new active disturbance rejection control (ADRC) strategy based on the cascade extended state observer (ESO) for airborne radar stabilization platform, which adopts two first-order ESOs to estimate the angular velocity value and the angular position value of the stabilized platform. Then makes the error signal which subtracts the estimated value of ESO from the output signal of the tracking-differentiator as the input signal of the nonlinear state error feedback (NLSEF), and according to the output signal of the NLSEF and the value which dynamically compensated the total disturbances estimated by the two ESO to produce the final control signal.FindingsThe simulation results show that, compared with the classical ADRC, the ADRC based on the cascade ESO not only estimates the unknown disturbance more accurately but also improves the delay of disturbance observation effectively due to the increase of the order of the observer. In addition, compared with the classical PID control and the classical ADRC, it has made great progress in response performance and anti-interference ability, especially in the complex air conditions.Originality/valueThe originality of the paper is the adoption of a new ADRC control strategy based on the cascade ESO to ameliorate the anti-interference ability of the airborne radar stabilization platform, especially the ability to suppress continuous interference under complex air conditions.

PurposeIn response to the severe lag in tracking the response of the Stewart stability platform after adding overload, as well as the impact of nonlinear factors such as load and friction on stability accuracy, a new error attenuation function and a parallel stable platform active disturbance rejection control (ADRC) strategy combining cascade extended state observer (ESO) are proposed.Design/methodology/approachFirst, through kinematic modeling of the Stewart platform, the relationship between the desired pose and the control quantities of the six hydraulic cylinders is obtained. Then, a linear nonlinear disturbance observer was established to observe noise and load, to enhance the system’s anti-interference ability. Finally, verification was conducted through simulation.FindingsFinally, stability analysis was conducted on the cascaded observer. Experiments were carried out on a parallel stable platform with six degrees of freedom involving rotation and translation. In comparison to traditional PID and ADRC control methods, the proposed control strategy not only endows the stable platform with strong antiload disturbance capability but also exhibits faster response speed and higher stability accuracy.Originality/valueA new error attenuation function is designed to address the lack of smoothness at d in the error attenuation function of the ADRC controller, reducing the system ripple caused by it. Finally, a combination of linear and nonlinear ESOs is introduced to enhance the system's response speed and its ability to observe noise and load disturbances. Stability analysis of the cascade observer is carried out, and experiments are conducted on a six-degree-of-freedom parallel stable platform with both rotational and translational motion.

Research on ADRC controller of bidirectional DC–DC​ converter for MMC-BESS

In order to overcome the problems of linear control method, which are unfavorable performance and highly depending on the accuracy of vehicle model, active disturbance rejection control(ADRC) strategy is used to complete active front wheel steering(AFS) control in this paper. According to the general principle of ADRC, a second order ADRC strategy is designed. Under the operation conditions of high speed single lane change and braking on µ-split road, the control performance is studied by means of simulation. The results show that the ADRC strategy can realize AFS control effectively and decrease the dependence on the accuracy of vehicle model. At the same time, the performance is better than that of PID control.

In this paper, an improved active disturbance rejection control (ADRC) strategy is proposed to solve the problem that the performance of the output side of the matrix converter (MC) is easily affected by the disturbance of the input side. According to the basic principle of the traditional ADRC, the non-linear feedback function is reconstructed, and the improved strategy is designed to solve the controller's dynamic buffeting. The experimental results show that the space-vector-modulated MC (SVM-MC) based on improved ADRC has good output performance in both steady-state conditions and dynamic disturbance conditions, and the output waveforms harmonic distortion is low.

In order to improve the performance of the traction permanent magnet motor drives without weight transducer for direct-drive elevator applications during starting operation, this article proposes a novel control method based on the high-gain nonlinear active disturbance rejection control (HNLADRC) strategy. First, the limitation of linear and nonlinear error decay function of active disturbance rejection control (ADRC) method is analyzed, which is not suitable for the complex situation at starting operation of the traction motor. A high-gain nonlinear error decay function based ADRC method is proposed, which can achieve better performance in the starting operation of the traction motor. Both the high-gain extended state observer (HNLESO) and the high-gain nonlinear error feedback law (HNLEFL) are constructed by the high-gain error decay function to improve the compensation accuracy of the starting torque and the dynamics of the speed loop. By analyzing the error decay performance of the HNLESO and the HNLEFL, it is proved that the HNLADRC method has a faster error decay rate. Experimental results show that the proposed method can obtain a shorter rollback distance and faster response capability.