High Order Sliding Mode Method Research Articles

Research on PMSM control system based on high order sliding mode method

A high-order sliding mode viewer using the stator current and rotor magnetic chain as state quantities is designed and implemented, which is based on the fourth-order state equation and can directly output the observed values of the rotor magnetic chain. To avoid the phase change of the magnetic chain due to the introduction of a low-pass filter, a vector equation of state filtering method is proposed to filter the dither signal through the magnetic chain equation by taking the observed deviation of the current as the sliding mode surface and inputting the equivalent control signal directly into the magnetic chain equation. Simulation results show that the designed extended sliding mode observer is able to accurately estimate the rotor position and speed at lower speeds without accurate compensation of the observed values for rotor information collection present in the counter potential and the rotor magnetic chain. The sensorless vector control system is characterized by robustness, wide speed range, and higher feasibility and effectiveness.

Double power sliding mode control of permanent magnet synchronous motor based on high-order sliding mode method

In view of the shortcomings of traditional sliding mode control of permanent magnet synchronous motor (PMSM), such as slow convergence, serious speed overshoot and outstanding chattering, an improved dual power approach law is proposed. Combined with the equivalent control, a high-order sliding mode rotor is designed by using the second-order nonsingular terminal sliding surface, which greatly improves the dynamic and static performance of the motor and effectively suppresses chattering. The simulation results show that the convergence speed of the improved dual-power reaching law is faster and the anti-disturbance ability of the system is significantly improved.

Variable Speed Control of Wind Turbines Based on the Quasi-Continuous High-Order Sliding Mode Method

The characteristics of wind turbine systems such as nonlinearity, uncertainty and strong coupling, as well as external interference, present great challenges in wind turbine controller design. In this paper, a quasi-continuous high-order sliding mode method is used to design controllers due to its strong robustness to external disturbances, unmodeled dynamics and parameter uncertainties. It can also effectively suppress the chattering toward which the traditional sliding mode control method is ineffective. In this study, the strategy of designing speed controllers based on the quasi-continuous high order sliding mode method is proposed to ensure the wind turbine works well in different wind modes. First, the plant model of the variable speed control system is built as a linearized model; and then a second order speed controller is designed for the model and its stability is proved. Finally, the designed controller is applied to wind turbine pitch control. Based on the simulation results from a simulation of 1200 s which contains almost all wind speed modes, it is shown that the pitch angle can be rapidly adjusted according to wind speed change by the designed controller. Hence, the output power is maintained at the rated value corresponding to the wind speed. In addition, the robustness of the system is verified. Meanwhile, the chattering is found to be effectively suppressed.

High-Order Terminal Sliding Mode Control for Brushless Doubly-Fed Machines

A novel sliding-mode variable structure(SMVS) control strategy is proposed to reduce the ripples of flux and torque of brushless double-fed machines(BDFM) based on direct torque control system. In order to ensure the constant switching frequency for the inverter, two hysteresis regulators in the conventional direct torque control system system are substituted by the SMVS controllers of flux and torque，nonsingular terminal sliding modes are designed to make the motor power reach the given values in a finite period of time. and the high-order sliding mode method is adopted to estimate the chattering phenomenon of the conventional sliding mode. Meanwhile, to obtain the parameters of High-order terminal sliding mode control, a method of fuzzy neural network is presented. The simulation results show that the nonsingular high-order terminal sliding-mode control can improve the robustness and dynamic response of the system.

Nonsingular terminal sliding-mode observer design for interior permanant magnet synchronous motor drive at very low-speed

A nonsingular high-order terminal sliding-mode observer of interior permanent magnet synchronous motor (IPMSM) is presented, of which the state variable is the current of rotor-oriented d-q reference frame, to obtain the accurate information about angular speed and rotor position for high-performance vector control system. A nonsingular terminal sliding-mode observer is used to improve dynamic response of the observer speed and robustness of the current observer, and the high-order sliding mode method is adopted to estimate the chattering phenomenon of the conventional sliding-mode. Meanwhile, to obtain the regulator parameters of speed and current loop, an integral-feedback method of estimating the rotor speed is adopted, and the inner current loop is realized using a decoupling and diagonal internal model control algorithm. Experimental results of 2 MW PMSM drive system show that the proposed method can accurately estimate the position and speed of the rotor, and the system has good dynamic and static performances.

Position-Sensorless Hybrid Sliding-Mode Control of Electric Vehicles With Brushless DC Motor

This paper proposes an efficient and robust control scheme for the position-sensorless electric vehicle (EV) with a brushless dc motor. The back electromotive force detection method is first adopted and improved to implement sensorless control of the motor. The equivalent circuits of the control system are depicted, and the mathematical models under normal driving and energy regeneration are then derived, respectively. By combining the advantages of nonsingular terminal sliding mode with the high-order sliding-mode method, a hybrid terminal sliding-mode (HTSM) control scheme for EV is put forward to guarantee both system performance and robust stability. Experimental results show that the scheme can perfectly implement position-sensorless control without Hall sensors and that the HTSM exhibits better performance and higher efficiency than the proportional-integral-differential (PID) controller. Furthermore, more energy is recovered, and by the proposed scheme, the driving range is improved 5.7% more than using the traditional controller.

Wireless Distributed Architecture for Therapeutic FES: Metrology for muscle control

This paper presents a Functional Electro-Stimulation distributed architecture based on a wireless network, for therapeutic training of disabled patients. On this distributed architecture, the movement (of disabled members) is artificially controlled by means of a global controller which pilots a set of stimulation units. The closed loop control system we developed for controlling muscle is based on a high order sliding mode method. In such wireless network-based control, the variable delay introduced by the network must be taken into account to ensure the stability of the closed loop. Thus, in order to characterize the medium on which the control is performed, we carried out accurate measurements of the architecture performances (stack-crossing, round-trip time, etc.). We then propose the use of a Kalman filter to predict the communication delay evolution, with the aim to exploit it within the closed loop control.