(1990). ENERGY FUNCTION ANALYSIS FOR POWER SYSTEM STABILITY. Electric Machines & Power Systems: Vol. 18, No. 2, pp. 209-210.

Energy function analysis for power system stability

A novel adaptive-gain supertwisting sliding mode controller: Methodology and application

This paper proposes an adaptive super-twisting algorithm based sliding-mode observer (STA-SMO) for surface-mounted permanent magnet synchronous machine (PMSM) sensorless control, in which voltage source inverter (VSI) nonlinearity is taken into consideration. An adaptive algorithm for online tuning the sliding-mode coefficients of STA-SMO is proposed based on the existing stable conditions. Thus, position estimation error can be reduced by the proposed adaptive algorithm in wide-speed range. Furthermore, voltage distortion due to VSI nonlinearity is online compensated to improve the accuracy of PMSM model. Because mismatch between reference and actual voltage due to VSI nonlinearity may bring large rotor position and speed estimation error, especially in low-speed range where distorted voltages may become dominant compared to actual voltages. Thus, a STA-SMO with adaptive sliding-mode coefficients and accurate voltage value could be obtained. Finally, the effectiveness of the proposed adaptive STA-SMO with online VSI nonlinearity compensation is verified on a surface-mounted PMSM by experiments.

Adaptive Second-Order Sliding-Mode Observer for PMSM Sensorless Control Considering VSI Nonlinearity

Parameter identification plays an important role in speed estimation schemes. This paper presents a speed estimation scheme based on second-order sliding-mode supertwisting algorithm (STA) and model reference adaptive system (MRAS) estimation theory, in which both variations of stator resistance and rotor resistance are deliberately treated. A stator current observer is designed based on the STA, which is utilized to take the place of the reference voltage model of the standard MRAS algorithm. The observer is insensitive to the variation of rotor resistance and perturbation when the states arrive at the sliding mode. Derivatives of rotor flux are obtained and designed as the state of MRAS, thus eliminating the integration. Furthermore, in order to improve the near-zero speed operation, a parallel adaptive identification of stator resistance is designed relying on derivatives of rotor flux and stator current. Compared with the first-order sliding-mode speed estimator, the proposed scheme makes full use of the auxiliary sliding-mode surface, thus alleviating the chattering behavior without increasing the complexity. The robustness and effectiveness of the proposed scheme have been validated experimentally.

Second-Order Sliding-Mode Observer With Online Parameter Identification for Sensorless Induction Motor Drives

In this paper we propose two modeling procedures for wind speed simulation. These procedures could be implemented on the structure of a wind turbine simulator during studies concerning stand-alone or hybrid wind systems. The evolution of a horizontal wind speed has been synthesized taking into account two components. The medium- and long-term component is described by a power spectrum associated to a specific site. The turbulence component is assumed to be dependent on the medium- and long-term wind speed evolution. It is considered as a nonstationary process. Two simulation methods for this component, using rational and nonrational filters are proposed. In both procedures, the turbulence model is defined by two parameters, which are either obtained experimentally, or adopted a priori, according to information from the considered site. Numerical results and implementation aspects are also discussed.

https://ieeexplore.ieee.org/iel5/8949/28458/01270996.pdf

Large band simulation of the wind speed for real time wind turbine simulators

In this work, a sampled-data model for surface-mounted permanent magnet synchronous motors (SMPMSMs) is proposed based on the symplectic Euler method. Then, based on the obtained model, a digital sliding-mode controller is designed for rotor velocity output tracking. Moreover, for rotor position and velocity and load estimation, a digital observer is designed. A separation principle is introduced in order to verify that the proposed controller can accomplish its task with estimated signals. Open-loop simulations predict that the sampled-data model obtained via the symplectic Euler method performs better than a model obtained with the classical explicit Euler method. Moreover, closed-loop simulations are carried on where the proposed controller is compared with a sampled continuous-time controller, where the controller here designed yields to better results even when the sampling period is increased. Finally, the performance of the proposed controller is verified by experimental tests.

Digital Sliding-Mode Sensorless Control for Surface-Mounted PMSM

Based on the complete model of the plant, a sliding-mode stabilizing controller for synchronous generators is designed. The block control approach is used in order to derive a nonlinear sliding surface, on which the mechanical dynamics are linearized. This combined approach enables us to compensate the inherent nonlinearities of the generator and to reject high-level external disturbances. A nonlinear observer is designed for estimation of the rotor fluxes and mechanical torque.

J.M. Canedo

Papers

Digital Sliding-Mode Sensorless Control for Surface-Mounted PMSM

Discontinuous controller for power systems: sliding-mode block control approach

Discrete-time sliding mode control of an induction motor

Decentralized sliding mode block control of multimachine power systems

Robust multimachine power systems control via high order sliding modes