This paper proposed the estimation of the magnetizing inductance and rotor resistance of the induction motors (IM) based on the extended Kalman-filter (EKF) in a real time emulator. So far, the performance of estimation for EKF in real time emulator has not been researched in case of motor parameters variation. Furthermore, inaccurate state space model of IM are applied within EKF in the published literature. This paper proposed the on-line estimation of the IM parameters with helping of the modified state space model minimizing the dependency of the state matrix indexes to state vector. To analyze the process of algorithm in F28377D emulator, the induction machine is modeled and solved by applying the numerical solutions. The analytically analyzation of the EKF algorithm and the real time emulator results are presented in this paper.

The comparative study on the field-oriented control (FOC) and direct-torque control (DTC) algorithms for interior permanent magnet (IPM) machine is presented in this paper. The study covers the dynamic performance of IPM under these two control strategies in constant torque and field weakening (FW) regions. The analyzation of power switches losses including the switching and conduction loss also are discussed as IPM is controlled with applying the aforementioned control strategies. So far, the critical evaluation on the basis of the power electronic losses and dynamic performance of IPM in all operational regions has not been presented. In this paper, the analytical and simulation results are provided in order to demonstrate the advantages and disadvantages of each control methodology.

This paper proposes an on-time estimation of induction machine parameters based on the extended Kalman-filter. So far, the real-time performance of Extended Kalman-filter algorithms has not been validated in the variation of motor parameters. Furthermore, the conventional parameter estimations in extended Kalman-filter has not been developed accurately based on the correct non-linear state space model. This paper proposes a new state space model of induction machine included motor parameters with less dependency to other model variables. This leads to achieve more accurate estimation results even in a situation where a sudden variation of motor parameters happens. This paper describes the proposed method analytically. Simulation results for an induction machine are presented and discussed.

This paper analyzes the unbalance problem of a stand-alone doubly-fed induction generator (DFIG) under unbalanced loads and proposes a compensation method to balance the stator output voltage. The proposed compensation method is developed based on a predictive current control (PCC) method implemented in the rotor current controller. The development of the PCC is based on the discrete model of the DFIG to predict an appropriate average rotor voltage vector to eliminate the rotor current error in the following switching period. The identified rotor voltage vector is then applied to the rotor-side converter (RSC) by using space-vector modulation (SVM) with constant switching frequency. To improve the control performance, a compensation method for time delay based on the prediction of the future rotor current at the end of current sampling period also is investigated. The proposed control scheme was tested by experiments with 2.2 kW DFIG to demonstrate its excellent steady-state performance as well as extremely fast dynamic response.

In this work a potentially universal algorithm for independent torque and reactive power control of doubly-fed machines is proposed. The method is inspired from the very essence of the machines dynamics and features an important asset compared to other model based approaches involving machine parameters or position encoder. It requires current and voltage measurements of the power side only. Applications include high performance drives and variable speed generators. Evidence of the good performance is shown through simulations and laboratory experiment.

An auxiliary drive is an electric machine and power electronic converter mounted in parallel with the main ship propulsion system. With a bidirectional electric drive system, Power Take In and Power Take Off are both possible, enabling hybrid operational modes. This gives the opportunity for slow speed motoring periods with improved prime mover operation and potentially lower emissions. Permanent magnet and induction machines are the two likely electrical machine choices. This paper presents an evaluation of the relative efficiencies of the two machine types when implemented on a shipboard auxiliary drive system. Depending on the operational strategy and the adopted propulsion system, the auxiliary drive is required to operate at various points in its operating envelope. By using a detailed computer model of an auxiliary drive system, the efficiencies at various operating conditions are calculated, showing how knowledge of the ship’s operational profile is essential in order to identify the configuration with the best efficiency.