Xinchi Wei

Modeling and Performance Analysis of a Dual-Stator Brushless Doubly Fed Induction Machine Based on Spiral Vector Theory

A detailed spiral vector model of the dual-stator brushless doubly fed induction machine is developed, which unifies the steady-state and dynamic analysis into a single-phase basis through introducing complex exponential variables. The modeling method is generalized to well apply to any ac machine with arbitrary winding layout. To validate the effectiveness of the proposed spiral vector model, steady-state characteristics are predicted based on the proposed model and experimentally demonstrated under all possible operation modes, namely, simple induction, cascaded induction, doubly fed synchronous, and double-cascaded induction. The dynamic performance under open-loop operation and closed-loop control is simulated, which is followed by experimental verifications.

Direct Voltage Control of Dual-Stator Brushless Doubly Fed Induction Generator for Stand-Alone Wind Energy Conversion Systems

This paper presents a dual-stator brushless doubly fed induction generator-based stand-alone wind energy conversion system (DSBDFIG-SA-WECS). With the advantages of compact structure, high reliability, and low cost, the DSBDFIG-SA-WECS shows great potential in wind energy applications. Based on the traditional stator-flux-oriented control (SFOC), an improved direct voltage control (DVC) is proposed for stand-alone operation. Performance analysis is carried out to evaluate SFOC and DVC in the aspects of control objects, orientation, feedback, and parameters involved. The DVC method is simple, robust, and cost-effective with the outer stator current sensors eliminated, and there are no extra parameters involved that the control performance can be enhanced. Fair comparisons are made in simulation to demonstrate better performance of the proposed DVC, and the effectiveness of DVC is further validated by experiment under variable speed condition.

Modeling and control of a novel dual-stator brushless doubly-fed wind power generation system

A novel dual-stator brushless doubly-fed induction generator-based wind power generation system (DSBDFIG-WPGS), with the merits of reduced converter scale, compact structure and high reliability, is proposed in this paper. System topology, operational principle and power flow of the DSBDFIG-WPGS are analyzed. Based on the modelling of the system, a vector control scheme is proposed to realize decoupled control of the reactive power and the speed. Furthermore, a speed based maximum power point tracking method is adopted in the system. The simulation results demonstrate stable operation of the DSBDFIG-WPGS and effectiveness of the proposed control scheme.

Analysis of a novel field-modulated dual-stator brushless wind generator with three electrical ports

This paper proposes a novel field-modulated dualstator brushless generator (FMDSBG) with three electrical ports, which owns two power windings and one control winding, used for the wind power system. The key innovation of the design is to utilize two different pole-pair space harmonics, interacting with the two power windings, respectively. The topology and operating principle of the proposed generator are described, and the no-load EMF, the no-load characteristic and the power capability are analyzed, then its superior performance is verified by the 2d-FEM.

Analysis of dual-stator HTS reluctance-rotor brushless doubly-fed wind generator

This, paper proposes a dual-stator high temperature superconductor (HTS) reluctance-rotor brushless doubly-fed wind generator, which owns two stators and one salient reluctance rotor sandwiched between two stators. Two sets of windings with different pole-pairs locate on the two stators, separately, named as control winding and power winding. The modulation of reluctance rotor makes two sets of windings couple with each other. The material of the control winding is HTS, while the power winding is made of common copper. The topology and operating principle of the proposed generator are described, and the basic performances are analyzed by the 2D-FEM.

Model predictive control of brushless doubly fed twin stator induction machine: A model reduction approach

This, paper presents a model predictive control (MPC) scheme and its model reduction approach for the brushless doubly fed twin stator induction machine (BDFTSIM). Firstly, the state-space equations of BDFTSIM, in terms of (power winding) PW flux, (rotor winding) RW flux, and (control winding) CW flux, is derived for developing the complete power model which is explicitly used to predict the future behavior. However, the MPC based on the complete model is too complicated for real time application. Therefore, a relevant model reduction approach is then developed for simplifying the power model while maintaining the accuracy under various conditions. Finally, by comparing the simulation results of the MPC based on the reduced model and complete model respectively, the effectiveness of the proposed method is verified.

Model predictive power control of a brushless doubly fed twin stator induction generator

This paper presents a model predictive power control (MPPC) scheme for the brushless doubly fed twin stator induction generator (BDFTSIG). State-space equations of the BDFTSIG, in terms of power winding (PW) current, control winding (CW) current, and PW flux, is specifically derived. A complete power model, which clearly reveals the relationship between power and the applied voltage vector, is then developed for the first time to accurately predict the future behavior of power. The proposed MPPC is realized by optimizing a predefined objective function that represents the absolute power error. It takes into account the discrete nature of power converters and does not require any additional modulator. Digital simulations are implemented, which clearly indicate the effectiveness of the proposed MPPC in terms of both steady-state and dynamic performance.

Unified spiral vector model of the Dual-Stator Brushless Doubly-Fed Induction Machine

An unified spiral vector model of Dual-Stator Brushless Doubly-Fed Induction Machine (DSBDFIM) is developed, which unifies the steady-state and dynamic analysis of the machine. And the modelling method well applies to any other ac machine with arbitrary phase number and winding layout. To verify the validity of the spiral vector model, steady state performance prediction based on the model is carried out under cascaded induction mode and doubly-fed synchronous mode. The spiral vector model also proves to be more comprehensive and versatile compared with the conventional d-q model in an open-loop dynamic simulation.