Dual Stator Winding Induction Machine Research Articles

A Novel Highly Efficient Torque-Sharing Algorithm for Dual Stator Winding Induction Machines for Various Speed Regions

A Novel Highly Efficient Torque-Sharing Algorithm for Dual Stator Winding Induction Machines for Various Speed Regions

Sensor-less Speed and Flux Control of Dual Stator Winding Induction Motors Based on Super Twisting Sliding Mode Control

This paper proposes a direct speed and flux control system for Dual Stator Winding Induction Machines (DSWIMs) based on Super Twisting Sliding Mode Control (STSMC). The proposed nonlinear controller which has finite time convergence of error to zero, is designed such that the Lyapunov stability condition is satisfied. Furthermore, a novel torque-sharing algorithm is introduced for DSWIMs. This algorithm enables them to operate in a wide speed region, including zero speed, such that the required electromagnetic torque is supplied by two winding sets based on their power ratings. In addition, a Sliding Mode Control (SMC) based full order observer is proposed for DSWIMs. This observer, which is able to estimate the winding fluxes, flux angles and rotor speed with high-accuracy, guarantees the optimal flux condition. The functionality of the proposed sensor-less DSWIM drive scheme is evaluated through some experimental tests performed on a 3.3 kW DSP-based DSWIM drive system. The experimental results confirm the effectiveness of the proposed control method, torque sharing algorithm and the full order observer in various speed regions.

Iron Loss Modeling in Dual Stator Winding Induction Machines With Unequal Pole Pairs and Squirrel Cage Rotor

This article pertains to dual stator winding induction machines (DSWIMs) modeling and proposes an equivalent electrical circuit for DSWIMs that considers the iron loss effect. It is proved that the iron loss in DSWIMs is comprised of two independent parts resulting from their winding sets. Accordingly, the proposed model is comprised of two distinct parts and it is based on the assumption of independent operation of DSWIM winding sets. This model is valid in dynamic and steady-state operation conditions. The dq0 form of the proposed model is derived in an arbitrary reference frame. In addition, based on this model the iron loss estimation in DSWIMs is presented. The proposed model is simulated in MATLAB/Simulink based on the parameters obtained from IEEE standard characterization tests performed on a 3.3-kW DSWIM and also some experimental tests are executed via a digital signal processor (DSP)-based DSWIM drive system. Comparison of the simulation and experimental results confirms the validity of the proposed model both in steady-state and transient conditions. Moreover, this comparison clarifies that the proposed iron loss estimation method can account for the iron loss with high accuracy.

Advances and Steady-State Development of Dual Stator-Winding Induction Machine

The dual stator-asynchronous machine is one type of emerging electric multiport machine. In this study, we build and simulate a dual stator-winding induction machine, including magnetic saturation with a squirrel-cage rotor. The mathematical models of a dual stator-asynchronous machine with stator mutual leakage inductance, formulated in phase coordinate system and generally transformed vector form of the space, are presented. Some early simulation and experimental test results, on a dual stator induction machine system that acts as a generator and supplies various loads under different conditions, are described and discussed.

Optimal Design of a Dual Stator Winding Induction Motor With Minimum Rate Reduction Level

Flux estimation of single winding induction machines (SWIMs) operating in a zero-speed region is challenging, since in this operation region, the voltage drop on the stator resistance value, which varies with the operating point, is not negligible. Furthermore, in this operation region, because of the interference between higher band frequencies of a dc-rejection filter with low-pass filter of the stator currents, the dc-offset of measured currents may distort the true values of the stator current. Dual stator winding induction machines (DSWIMs), which have two sets of three-phase windings with different number of pole pairs and adapt a standard squirrel cage rotor, have overcame the associated problems of SWIMs in the zero-speed region. Nevertheless, DWSIMs have lower power rating than SWIMs if they use the same stator and rotor frames. In this article, an optimal design procedure is proposed for DSWIMs, which benefits the advantages of DSWIMs and surmounts the rate reduction problem as much as possible. In this regard, the optimal flux levels ratio of winding sets and the best pole pair ratio are determined first. Afterward, the winding specifications are designated to have maximum output power, while the DSWIM advantages, especially the zero-speed region operation capability, remain valid. A DSWIM is designed, simulated in ANSYS/MAXWELL and fabricated based on the proposed method and utilizing commercially available standard stator and rotor frames. Experimental assessments verify that the DSWIM prototype has improved the rate-reduction problem up to 19% in comparison to similar proposed DSWIMs.

Optimal Reference Frame Angle Approach for Air-Gap Flux Minimization in Dual Stator Winding Induction Machines

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.

Behavior of a Dual Stator Induction Machine Fed by Neutral Point Clamped Multilevel Inverter

Use of multilevel inverters with induction machines has become popular in most energy conversion and management systems. The present paper discusses the behavior of the dual stator-winding induction machine (DSIM) for the power source, which is a power supply with Neutral Point Clamped (NPC). Multilevel inverter with PWM technique control is analyzed. The DSIM control is obtained by the PWM technique to multicarrier PWM technique and after a comparative study of various characteristics of the DSIM taking into account the different electrical offsets between the two stars (0°, 30°, 60°). The gap between the two stars was considered, and it is impacted on torque and rates harmonic distortion of circulation currents.

Modelling and analysis of dual stator-winding induction machine using complex vector approach

In this work, complex vector modelling technique is utilized to develop and simulate a dual stator-winding induction machine with squirrel-cage rotor. The transient and dynamic performances of the machine under two cases of input conditions are analysed and presented both at no load and when a constant load torque is applied. The modelling and simulation has been carried out in a step-wise procedure that clearly set forth for the complex vector Simulink implementation in a MATLAB-Simulink environment. The approach presented in this work can easily be applied to other types and configurations of electric machines and drives.

Dual Stator Winding Induction Machine: Problems, Progress, and Future Scope

This paper gives an overview of the topological variations of multi-winding induction machines (IMs) and drives. The study is restricted to IMs having two distributed windings on the stator and a brushless rotor. The mathematical modeling techniques and control algorithms available in the literature are highlighted. Being magnetless and brushless, a Dual Stator Winding IM is highly reliable, maintenance free, and economic. Thus, it possesses the necessary potential to become a part of ac and dc microgrids. Recent research trend shows growth in the application of such generators for off-grid and grid-connected systems.

Total Airgap Flux Minimization in Dual Stator Winding Induction Machines

Multiphase machines are gaining attention in specific applications due to their increased reliability and the possibility to split the power between more than one inverter. Dual stator winding machines can be seen under certain conditions as two independent induction machines coupled by the rotor. To ensure control independence of both windings, airgap flux saturation must be avoided. Proper flux synchronization of both windings is required to achieve this goal while maximizing the torque per ampere ratio of the machine. The conditions to obtain proper orientation of the fluxes are discussed in this paper, and the inverter control scheme to perform such orientation is developed.

Flux level selection in vector-controlled dual stator winding induction machines

The dual stator winding induction machine has two three-phase stator windings with dissimilar number of poles. This machine can be regarded from the point of view of control as two different induction machines coupled by a rotor. To improve the machine's performance, the total flux generation must be correctly distributed between the two windings. This study focuses on the flux distribution necessary to achieve a nearly maximum torque per stator ampere operation, which is indicated in applications requiring high dynamics. In addition, efficiency and voltage utilisation will be also considered.

Total Airgap Flux Minimization in Dual Stator Winding Induction Machines

Multiphase machines are gaining attention in specific applications due to their increased reliability and the possibility to split the power between more than one inverter. Dual stator winding machines can be seen under certain conditions as two independent induction machines coupled by the rotor. To ensure control independence of both windings, airgap flux saturation must be avoided. Proper flux synchronization of both windings is required to achieve this goal while maximizing the torque per ampere ratio of the machine. The conditions to obtain proper orientation of the fluxes are discussed in this paper, and the inverter control scheme to perform such orientation is developed.

Dual stator winding induction machine drive

A new dual stator winding induction machine drive is described in this paper. The proposed induction machine consists of a standard squirrel-cage rotor and a stator with two separate windings wound for a dissimilar number of poles. Each stator winding is fed from an independent variable-frequency variable-voltage inverter. The proposed drive offers such advantages as speed sensorless operation, better reliability, and more flexibility to manipulate the resultant torque-speed curve of the motor. In the proposed drive, zero-speed operation is achieved by independently controlling the two sets of stator currents, hence, maintaining a minimum electrical frequency independent of the mechanical speed. This feature is especially important to minimize the negative impact of the stator resistance influence at low-speed operation and it greatly simplifies the implementation of speed sensorless control schemes. The drive is well suited for either constant volts per hertz or field-oriented (FO) operation. Circulating harmonic currents, common to most dual stator machines, are eliminated by the dissimilar pole number in each stator winding.