Loss Investigation for Multiphase Induction Machine under Open-Circuit Fault Using Field–Circuit Coupling Finite Element Method

This paper focuses on the loss estimation for the multiphase induction machine (IM) operating under fault-tolerant conditions through the field–circuit coupling finite element method (FEM). Both one-phase and two-phase open-circuit faults of a seven-phase IM are researched, and different spatial positions of the fault phases are taken into consideration. The magnitudes and phase angles of the residual phase’s current are deduced based on the principle of equal magnitude of the residual phase currents and unchanged fundamental magnetic motive force (MMF). The magnetic fields’ coupling between the fundamental and harmonic planes is analyzed. Then, the time-stepping electromagnetic fields calculation of the seven-phase IM are carried out under the commercial software Simplorer–Maxwell environment. The transient and steady performance for both the health and fault conditions are obtained based on the rotor field-oriented control (RFOC) strategy. The Joule loss and iron loss are calculated for the torque step and slope responses. The seven-phase motor driving platform is established to verify the numerical calculation results. The proposed method is effective for predicting the loss and designing a reasonable operating range for multiphase IM operating under fault-tolerant conditions considering the thermal balance.

New model of electric traction drive based sliding mode controller in field-oriented control of induction motor fed by multilevel inverter

This paper presents a new model of electric traction drive for electric vehicle. The sliding mode speed controller applied in the Indirect Rotor Field Oriented Control is used to control the induction motor fed by the five levels Neutral Point Clamped inverter (NPC). The simulation results showed the high performances dynamics and high robustness of the proposed model, that are reflected by faster startup and good speed tracking performances in terms of response time, oscillations and disturbance rejection. Also, a comparative study between different inverter topologies: two levels inverter, three levels NPC inverter and five levels NPC inverter has been carried out. From the spectral analysis, the five-levels NPC inverter fed drive provides better dynamics of voltage and current with reduced total harmonic distortion (THD).

dSPACE Implementation of Improved Indirect Rotor Field-Oriented Control of Asynchronous Motor using Fuzzy Self-Adjustable Proportional Integral Controller for Electric Vehicle Applications

This paper deals with the indirect rotor field-oriented control of asynchronous motor whose speed is controlled by a fuzzy self-adjustable proportional integral controller. This motor drive is used to propel an electric vehicle. The designing and the implementing of the fuzzy self-adjustable proportional integral controller are presented. This controller is proposed as a solution to compensate for the effect of the machine parameters variation and the external conditions. The characteristic of this controller is its capacity to adapt in real time its gains in order to reject the machine parameters disturbances. A series of measurements has been achieved to prove the performances of the improved drive using the proposed controller. Experimental results showed the high-speed tracking and the rejection disturbances capacity of the fuzzy self-adjustable proportional integral controller.

Rotor Field Oriented Control of Resonant Wireless Electrically Excited Synchronous Motor

In order to solve the problems of wear and spark of the brush and slip ring in an electrically excited synchronous motor (EESM), based on the principle of magnetic resonance coupling wireless power transfer (MRC-WPT), a resonant wireless excitation system of EESM is designed. By modeling the EESM and analyzing the rotor field oriented control (RFOC) method, a control system of the resonant wireless EESM (RW-EESM) is established. Furthermore, the stator current distribution strategy is analyzed. Finally, a test of the RE-EESM prototype is carried out. The test results show that the motor can realize no-load stable operation, and the test speed is maintained at 85 r/min. The results show that the wireless excitation scheme of EESM is feasible, and the RFOC of RW-EESM motor is reasonable.

Loss minimization of induction machines during torque transients

This article presents a new design of an energy optimization approach to induction motor drives. The proposed control strategy is based on a designed cost function given as a weighting sum of power and energy models and subjected to the dynamic of a low-order current-fed induction motor model, which considers only the dynamics of the rotor flux and the mechanical equation as constraints to the problem. Such a strategy uses the concept of off-line optimal closed-loop control. Considering the case of a random desired torque, the resolution with suboptimal conditions allows a time-varying rotor flux that converges to the optimal solution and minimizes energy in a dynamic operation. This solution is presented in an analytical form and is dedicated to optimizing a transient regime characterized by a random load torque. This command law will become invariant with respect to time and will asymptotically tend to a stationary optimal solution. Aiming to check the validity of the proposed algorithm, a comparison study is conducted between rotor-field-oriented control operating with a suboptimal rotor flux and rated constant-flux control. The simulation and experimental results obtained for a 1.5-kW laboratory induction motor demonstrate the effectiveness of the proposed strategy.