In order to enhance the speed control performance of the permanent magnet synchronous motor (PMSM) with internal and external disturbances, a new adaptive terminal sliding mode reaching law (ATSMRL) is proposed with continuous fast terminal sliding mode control (CFTSMC). Firstly, the ATSMRL is presented with the aim of reducing the input control efforts, which can dynamically adopt all positive aspects in terms of the finite time convergence, high tracking precision, and reduction of the chattering in the control input of the system. Secondly, an extended sliding mode disturbance observer (ESMDO) is designed to estimate the total disturbances of the system, and then the estimated disturbance has been brought for the feed-forward compensation technique, which would enhance the disturbance rejection ability of the system. Afterwards, the close loop stability is validated by the Lyapunov function. Finally the comprehensive numerical and experimental analyses have been carried out to demonstrate the superiority of the ATSMRL method than that of terminal sliding mode reaching law (TSMRL).

To promote the drive performance of permanent magnet synchronous machine (PMSM), such as tracking accuracy of both speed and current, one improved deadbeat-based predictive current control (DPCC) scheme based sliding mode is proposed in this paper. Firstly, one novel PMSM model is derived by considering uncertainties of both parameters and external disturbances. Secondly, in order to improve the dynamic response of PMSM drive system, both sliding mode control (SMC) and DPCC are employed to control the speed and current respectively. Thirdly, a unified high-order sliding mode observer (HSMO) is designed for the estimation of disturbances and uncertainties in the speed and current loops. Furthermore, the estimated values are compensated with feedback to the designed SMC and DPCC to increase the speed robustness and current tracking accuracy. Comprehensive simulation and experiments demonstrate that the proposed control strategy is strongly robust to acute variations of load and machine parameters, and it is testified to have better speed and current tracking performance.

The new continuous fast terminal sliding mode control (CFTSMC) is adopted in this paper for the speed regulation of permanent magnet synchronous motor (PMSM) drive applications. The CFTSMC method has a capability to converge the error faster, provide higher tracking accuracy and robust against the load disturbances. However, the CFTSMC method needs high switching gain during the strong disturbances, which introduces the chattering and steady state variation to the system. To address these issues, a composite CFTSMC technique based on the extended state observer (ESO) is proposed in this paper. The ESO is used to estimate the system disturbances for feed-forward compensation. The ESO based CFTSMC method needs smaller switching gain than the CFTSMC method. Moreover, the ESO based CFTSMC method has a strong robustness against load disturbances, better convergence rate and better tracking accuracy than the CFTSMC and conventional continuous sliding mode control (CSMC) method. The superiority of the proposed control method is verified by Lyapunov function and confirmed by the simulation and experimental results.

A novel sliding mode based extended state observer (SMESO) is proposed to improve thedisturbance rejection ability and enhance the dynamic performance of permanent magnet synchronous motor (PMSM) drive systems. Firstly, an extended state observer (ESO) based onthe fast terminal sliding mode control (FTSMC) method is developed for better comparison, which canimprove the robustness against load disturbances, finite time convergence, and get effective reduction of the chattering phenomenon. The SMESO based FTSMC is then developed by using the SMESO to estimate the system total disturbance, and input the signal to a feed-forward compensation controller to further improve the system dynamic performance. The closed loop stability analysis is conducted by using the Lyapunov stability function. The superior effectiveness of the proposed method is confirmed by comprehensive simulation and experiments.

Operating in the high-speed range is necessary for high-performance permanent magnet synchronous motor (PMSM) drives. However, due to the back electromotive force effect, the PMSM is approaching the voltage limit at field decreasing scope. This paper presents a new flux-weakening scheme along with an improved vector control strategy to alleviate the influence of this problem. Control parameters of the anti-windup proportional and integral (AWPI) controller are optimized off-line in relying on an adaptive velocity particle swarm optimization (AVPSO) algorithm. The AVPSO algorithm considers the summation of AWPI measurement error which is the objective function of the optimization problem without knowing the transfer function of the plant. Hence, the tuned flux-weakening controller with a filter is used to set the flux level without saturating the current controllers. Meanwhile, the other controllers of inner and outer loops award a great dynamic and steady-state performance for the PMSM. In the proposed scheme, the flux weakening control is not dependent on machine parameters which adapts the flux level automatically and provide a fast transition between the constant torque region and the field weakening region. Effectiveness and advantages of the proposed scheme are presented in this paper through both simulation and experimental results.

Doubly-fed variable speed pumped storage (VSPS) unit is an advanced hydropower system. In pumping mode, its input power can continuously be adjusted within a certain range via changing speed. Thus, it overcomes the major defect that the pumped storage unit cannot provide frequency regulation services to the power grid in pumping mode. However, for the pumping mode VSPS, how to establish its model is still a problem. In this article, an electromagnetic-electromechanical transient multi-time scale model of pumping mode VSPS is presented. This model depicts the intrinsic speed-power regulation characteristics and the extrinsic power-frequency coupling characteristics of pumping mode VSPS, which can be used for the power grid frequency regulation analysis. Firstly, the hydraulic subsystem model of VSPS is established within the electromechanical transient time scale. The model is built based on the variable speed characteristics of the reversible pump-turbine (RPT) in pumping mode and considers the hydrodynamics and additional friction effects of the wicket gate in the water conveyance system. Secondly, the electric subsystem model of VSPS is established within the electromagnetic transient time scale. The model mainly describes the operation characteristics of a doubly-fed induction machine (DFIM) and the control properties of the inner and outer loops of the back-to-back (BTB) converter system. Finally, comprehensive simulation and experimental results have fully verified the established model and theoretical analysis.