This paper proposes and implements a super-twisting sliding mode direct power control (SSM-DPC) strategy for a brushless doubly fed induction generator (BDFIG). DPC has fast and robust response under transient conditions; however, it suffers from active and reactive power ripples and current distortions, which degrades the quality of the output power. In contrast, vector control has good steady-state current harmonic spectra; however, it is not robust to machine parameters variations, and thus needs a phase-locked loop for synchronous coordinate transformations. The SSM-DPC strategy controls active and reactive power directly without the need of the phase-locked loop. Moreover, its transient performance is similar to DPC and its steady-state performance is the same as vector control. The proposed controller is robust to uncertainties toward parameter variations and achieves constant converter switching frequency by using space vector modulation. Simulation and experimental results of a 2 MW and 3 kW laboratory-scale BDFIG are provided and compared with those of integral sliding mode and DPC to validate the effectiveness, correctness, and the robustness of the proposed strategy.

This paper is concerned with flux and voltage vector-oriented control of a promising brushless doubly fed reluctance machine (BDFRM) for generator and drive systems with limited adjustable speed ranges (e.g., wind turbines and/or pump drives). The BDFRM has been receiving increasing attention because of the low capital and operation and maintenance costs afforded by using partially rated power electronics and the high reliability of brushless design. Furthermore, it has the potential to offer competitive performance to its well-known slip-ring counterpart, i.e., doubly fed induction generator. The experimental studies have evaluated the control algorithms on a custom-built BDFRM in both motoring and generating modes under the maximum torque per inverter ampere conditions. The test results achieved should make a step forward toward the development of robust generic controllers for doubly excited machines.

This paper presents the conceptual analysis, comparative simulation, and experimental evaluation of voltage and flux vector-oriented control of a promising low-cost brushless doubly-fed reluctance generator (BDFRG) technology for variable-speed wind turbines with maximum power point tracking. The BDFRG has been receiving increasing attention because of the use of partially rated power electronics and the high reliability of brushless design, while offering performance competitive to its popular slip-ring counterpart, the doubly-fed induction generator. The development and viability of the two parameter-independent controllers have been validated on a custom-made BDFRG prototype using the maximum torque per inverter ampere strategy for the speed and loading conditions commonly encountered in wind power applications.

This paper presents the development and experimental validation of a novel angular velocity observer-based field-oriented control algorithm for a promising low-cost brushless doubly fed reluctance generator (BDFRG) in wind power applications. The BDFRG has been receiving increasing attention because of the use of partially rated power electronics, the high reliability of brushless design, and competitive performance to its popular slip-ring counterpart, the doubly fed induction generator. The controller viability has been demonstrated on a BDFRG laboratory test facility for emulation of variable speed and loading conditions of wind turbines or pump drives.

In order to realize sensorless control for brushless doubly-fed induction machine (BDFIM), this paper presents a model reference adaptive system (MRAS) observer, designed based on the error of the control winding current. Furthermore, a phase-locked loop (PLL) is employed to estimate the current winding position and rotor speed. Consequently, a detailed theoretical derivation proves that the MRAS observer is stable and the dynamic performance is good. Thus, it does not cause any estimated speed error in steady state. Moreover, the estimated position error is bounded and trivial, thus its effects on the sensorless control of the BDFIM are neglected. The correctness, feasibility, and robustness of the proposed sensorless control method are verified by means of experimental validation on a 30kW test rig.