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This article proposes a nonlinear controller for brushless doubly-fed induction motor (BDFIM) drives on the basis of input–output feedback linearization (IOFL). In the proposed control approach, first, the maximum torque per inverter ampere (MTPIA) control strategy is considered by applying a fifth-order (reduced-order) model of BDFIM. By realizing the MTPIA, the control winding (CW) current magnitude is minimized under the constraint of constant torque. The realization criterion of MTPIA approach is independent of torque level and CW frequency. To fairly share the current between stator windings and minimizing the total current magnitude for a given torque, the MTPIA idea should be extended. Since, the power winding (PW) of BDFIM is not controllable, obtaining this purpose is a challenge. Therefore, to solve this problem, the model-based maximum torque per total ampere (MTPTA) control is introduced for BDFIM drives and the conditions for realizing this strategy are determined. It should be noted that the total amperes refer to the sum of the PW and the CW current magnitudes. In addition, using the fifth-order model of BDFIM, a nonlinear controller is developed based on IOFL technique which is capable to force the deviation from realization criterion of both proposed strategies to zero while the torque is controlled with high accuracy. The overall stability of the proposed controller is proven using the Lyapunov control theory. The validity of the proposed approach is finally verified by simulation and experimental results. [ABSTRACT FROM AUTHOR]

Dual stator winding induction machines (DSWIMs), which have two sets of three-phase windings with unequal pole pairs in their stator and a standard squirrel cage rotor, have overcame the narrow speed operation region and circulating current problems exists in other types of dual winding machines. These advantages are resulted from the independent operation of their winding sets. The independent operation of winding sets will be guaranteed if the flux saturation is avoided. This letter proposes a novel reference frame angle determination technique that not only guarantees the flux saturation avoidance but also results in flux optimization in DSWIMs. Despite pervious methods, the proposed method does not require position or speed sensor and it is easily applicable in various control schemes and in different reference frames. This method is implemented in a flux and torque vector control system for driving a 3.3 kW DSWIM. The experimental results confirm the effectiveness of the proposed method. Moreover, by implementing the proposed method, the torque sharing between the two winding sets is properly done according to the power rating of each of them. [ABSTRACT FROM AUTHOR]

This study presents a novel online, accurate and simple model‐based maximum torque per ampere (MTPA) strategy for input–output feedback linearisation control of induction motor (IM) drives. Despite conventional MTPA control principles which are under the assumption of iron loss neglecting, the proposed strategy takes iron loss effect into account. This study highlights the iron loss influence on MTPA scheme. Firstly, the cross‐coupling effects in the IM model and torque non‐linearity due to the iron loss in torque–speed characteristics of the IM are discussed. The criterion for the MTPA scheme is then introduced and investigated by gradient approach so that when the gradient vectors of the torque and stator current magnitude are parallel, the MTPA strategy is satisfied. Finally, to confirm the validity of the proposed control scheme, experiments are carried out. [ABSTRACT FROM AUTHOR]

Among the conventional loss minimisation algorithms (LMAs), the model‐based approaches have the advantages of fast response and high accuracy. Here, a novel online model‐based power losses minimisation approach is presented for indirect field‐oriented control (IFOC) of induction motor (IM) drives. The proposed method is introduced as maximum torque per power losses (MTPPL) in which the power losses for a given torque are minimised. The results demonstrate that the proposed approach preserves the LMA merits, while the criterion for the MTPPL scheme is achieved. The mentioned criterion is investigated by a gradient approach so that while the gradient vectors of the torque and power losses are parallel, the MTPPL strategy is realised. The closed‐loop IFOC of the MTPPL approach is implemented in real time for a laboratory 2.2 kW three‐phase IM drive. The experimental results show the capability and validity of the proposed control scheme. [ABSTRACT FROM AUTHOR]

In this paper, speed and torque control modes (SCM and TCM) of synchronous reluctance motor (SynRM) drives are proposed based on emotional controllers and space vector modulation under an automatic search of the maximum-torque-per-ampere (MTPA) strategy. Furthermore, in order to achieve an MTPA strategy at any operating condition, after recognition of transient state by two new indicators, a search algorithm changes the stator flux magnitude automatically. The indicators operate based on slip effect generated at transient conditions in a SynRM with cage. The performance of the proposed controller is compared with an optimized conventional PI controller under different operating conditions. Simulation and experimental results demonstrate the benefits of the proposed approach. This structure shows superiority of the proposed method, such as fast dynamic, simple implementation and robustness to parameter variations and external disturbances in both TCM and SCM. In addition, the proposed MTPA strategy shows a reliable and fast response to operating point change. [ABSTRACT FROM AUTHOR]

Control issue in electrical drives mainly deals with the dynamic behavior, which is based on the deviation of variables. The deviations play a straightforward role in presenting the various capabilities and merits of the electric drive systems. This paper describes, for the first time, a deviation-based torque control of synchronous reluctance motor (SynRM) drives with no need to know the motor parameters. The proposed control system is designed by using a normalized deviation model to derive linear and simple relationships amongst different machine signals. Therefore, the commonly used proportional–integral current regulators are replaced by novel deviation equations. As a result, the proposed approach provides facilities to electric drives, including control system simplicity, parameter independency, and no need for controller tuning. The theoretical findings are verified by those experiments. The obtained results are reported for a typical SynRM drive. In addition, performance comparison of the control system with a general PI controller-based field-oriented control scheme is carried out. It is expected that the proposed approach contributes to other electrical drives to simplify the machine equations, reduce control complexities, such as the number of conventional controllers, and overcome the problem of machine parameter dependency. [ABSTRACT FROM AUTHOR]