Multidirectional power flow control among double winding six-phase induction machine winding sets

The interest in multiphase drives has been steadily growing during the last decade due to the promising potentials offered by multiphase machines over conventional three-phase counterpart. In this context, six-phase induction machines are preferably used in many diversified high-power applications. Generally, thanks to its improved flux distribution, the asymmetrical six-phase winding topology fed from two three-phase voltage source inverters (VSIs) is commonly employed with isolated neutral points to prevent the flow of zero sequence currents and to limit the number of current controllers to four instead of five when neutral points are connected. In this paper, an innovative design of a six-phase dc-ac inverter is proposed for such type of six-phase ac machines based on the single-ended primary-inductance converter (SEPIC) topology. The proposed topology employs only four active-legs with eight switches with the same output voltage magnitudes as in conventional VSIs and without the mandatory dead-time between switches in the same-leg. Also, it naturally delivers a pure sinusoidal waveform at the output stage. The principle of operation of the proposed inverter topology is investigated in details and assessed through a detailed simulation study of an open-loop control system.

This paper analyzes a six-phase two-motor drive, consisting of a six-phase voltage-source inverter (VSI), a six-phase induction machine, and a three-phase induction machine. Stator windings of the two machines are connected in series in an appropriate manner. This enables full decoupling of the dynamics of the two machines by means of vector control. Detailed mathematical modeling of the system is performed and the set of d-q equations, describing the two machines connected in series to a six-phase VSI, is developed. The resulting model clearly shows the possibility of independent vector control of the two machines, although a single VSI is used as the supply. An experimental rig is constructed and existence of the decoupled dynamic control of the two machines supplied from a single VSI is fully verified by extensive experimental testing.

Multiphase Induction machine offers numerous advantages compared to the conventional three phase induction machine. Among the different types, the six-phase induction machine is most common, due to the flexibility in converting a three phase to six phase. By splitting the phase belt of a three phase induction machine, a six-phase induction machine is realized. The areas of application of multiphase (>3) machines are enormous, mostly where reliability is paramount. This paper presents the analysis, modeling and simulation of a 5Hp, 50HZ, 4 pole, 24 slots asymmetrical six-phase induction machine for submarine application. With the help of MATLAB software, the models developed are simulated and results in the form of computer traces of the dynamic performance of the machine at start-up are presented and discussed. This investigation shows that the replacement of three phase with a six phase machine is both technically and economically advantageous.

The six-phase induction machine (SPIM) has two sets of three-phase stator windings spatially shifted by 30 electrical degrees. It has many advantages, such as reducing the torque pulsations, enhancing the power handling capability. The matrix converter (MC) is a very promising converter, which has the following characteristics: operation with unity power factor, bidirectional power flow. In this paper, six-phase induction motor driven by the six-phase matrix converter has been proposed. It can combine the advantage of the SPIM and the MC. A direct modulation algorithm is presented. The control system can realize bidirectional power flow and the unity power factor. Simulation results have tested the performances of the proposed method.

A new circuit-oriented model for the analysis of six-phase induction machine performances

Three phase induction motors are employed in Textile mills, Agriculture and in almost all the machine tools. More than 60% of electrical energy generated being consumed by the induction motors. Hence, even a small contribution in the improvement of the power factor and efficiency will be cost effective. The power factor and efficiency of an induction motor is based on the shaft load and in order to improve the same, multi windings are suggested in the same stator. In multi winding induction machines, when one set of windings is connected to a three phase a supply, a revolving magnetic field of constant magnitude is developed in the air gap which is responsible to work as a conventional induction motor to meet the mechanical load and to develop a three phase EMF in the other winding that works as an Induction Alternator (IA).Double Winding Induction Motor (DWIM) also provides an opportunity to load each winding individually to its rated capacity. A small three phase load or a single phase load may be connected to the second set of winding. The dependency of separate supply for this load is eliminated. Hence, improvement in the efficiency, power factor and energy conservation is made possible in these machines. In order to validate the problem statement, a 3-phase, 3.0 kW, 415 V Double Winding Induction Motor(DWIM), a 3-phase, 3.0 kW, 415 V Double Winding Synchronous Reluctance Motor (DWSyRM), a 3-phase, 2.2 kW, 415 V Three Winding Induction Motor (TWIM) have been designed, fabricated and tested. Two controllers have been designed, one for a DWIM to operate the motor in power balancing and maximum efficiency modes of operation and other to operate TWIM at three different voltage levels depending upon the shaft load. In this paper, detailed comparisons of performances of three multi winding machines are presented.

This paper provided a comparative study between linear and nonlinear controllers of a solar photovoltaic (PV) water pumping system using an induction motor and a centrifugal pump. For linear controller, classical Perturb and Observe was selected to ensure the operation of the PV system at the maximum power point (MPP) and is combined with Indirect Rotor Field Oriented Control (IRFOC) based on a conventional proportional integral speed regulator chosen to control and to optimize the rotor speed. In second and third controllers, Backstepping and first order sliding mode controls were proposed for controlling the whole system. To regulate and optimize rotor speed in the nonlinear controller, all considered control techniques were combined with IRFOC in order to establish easy control laws. In addition, MPP was tracked by acting on the DC-DC converter and using its mathematical model for developing control laws. Maximum delivered power was used as reference signal for optimizing actual rotor speed. The controlled system is operated without mechanical sensors. Estimators of rotor speed and load torque disturbances were proposed based on the mathematical model of induction motor and centrifugal pump and using only available output measurements. Induction motor was supplied by a voltage source inverter controlled using a PWM technique. Stability based on Lyapunov functions of the closed-loop system was evaluated. Simulation results were investigated and reveal some very interesting features and the effectiveness of the nonlinear proposed strategies.

One of the main challenges of voltage source converter based high voltage direct current (VSC-HVDC) transmission systems is the AC faults at the grid side. This work introduces the integration of multiphase induction machine (IM) based flywheel energy storage systems (FESS) with VSC-HVDC systems for AC side fault ride through purposes employing modular multilevel converters (MMC). MMCs have become suitable candidates for medium/high power energy conversion systems due to the capability of simply extending the levels of the converter while retaining high levels of reliability. In order to enhance the storage system reliability, a dual three phase IM is used to drive the FESS due to its fault tolerance capability. In this paper, the performance of the FESS is investigated under the operation of a dual three phase IM being driven by two three-phase MMCs. To step-down the DC-link voltage of the HVDC system to a proper voltage level for IMs, the DC-link voltage is divided into two series connected capacitor, and each capacitor voltage is fed as an input DC voltage for each three- phase MMC. The control strategies of the MMCs and the IM are presented, in addition to the IM mathematical model. Simulation case studies are performed using MATLAB/Simulink to validate the proposed system.

This paper focuses on the performance evaluation of a dual stator de-coupled rotor six-phase permanent magnet synchronous generator (DSDRSP-PMSG) for wind power applications. For this application, the generator should have essential advantages like high power density, light in weight, high fault-tolerant capability and high reliability. Due to the dual stator and de-coupled rotor, the power density of proposed generator is high. The two sets of 6-phase windings also ensure their high reliability and high degree of fault tolerance capability of generator. For performance evaluation, the finite element method (FEM) is chosen because of its more accurate method of analysis. For the optimal design, magnetostatic and transient mode of analysis are considered. For the performance evaluation, transient mode of analysis is opted. The electromotive force (EMF), percentage (%) Total Harmonic Distortion (THD) and electromagnetic torque, % ripple in the torque and voltage-current characteristic are investigated for the proposed generator.

A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper.The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

Multiphase induction machines have gained more attentions due to their superior fault tolerant capabilities. This work aims to assess the Broken Rotor Bar (BRB) faulty operation of asymmetrical six-phase Induction Machine (IM). Additionally, a comparison in terms of BRB fault feature between the mentioned machine and conventional 3-phase IM has also been performed. Assessment process has been performed initially using Finite Element Algorithm (FEA). Then, a prototype has been re-wound for semi-12-phase arrangement which is an alternative name of asymmetrical 6-phase IM. It has been confirmed experimentally that the BRB fault indicators, the Side Band Harmonic Components (SBHC) of stator current for asymmetrical 6-phase IM, are greater than those of their 3-phase counterparts. Analysis has been concluded with various BRB fault scenarios including single and double BRB cases with variable loading conditions. Furthermore, a fault classifier has also been proposed which could detect and classify the BRB fault for asymmetrical 6-phase IM.

In this paper, a control scheme is developed for a Voltage Source Inverter (VSI) used in peak shaving applications. The developed control first allows the VSI to reduce the power consumption from the grid during peak demand. Secondly, the control strategy allows the VSI to mimic the Power Factor (PF) correction feature usually achieved by capacitor banks and, finally, inherits the capabilities of active harmonic filters to suppress the harmonic content in the line current. The proposed control strategy is developed using MATLAB/Simulink and validated experimentally with the VSI connected to the grid in parallel with non-linear loads. The control scheme was validated under two different operation scenarios: under high Total Harmonic Distortion (THD) and under low power factor conditions. The presented analysis highlights the overall power quality improvements attained from the control strategy when interfacing the VSI with the grid and the peak shaving system.

In this paper, Design and development of control circuit algorithm of 3-Φ Voltage Source Inverter (VSI) using Unipolar Sinusoidal Pulse Width Modulation (SPWM) techniques is proposed using STM32F407VGTx discovery board interfaced with MATLAB Simulink Environment. For implementing 3-Φ VSI, this method is most useful as it will eliminate complexity of control circuit algorithm occurred due to analog circuit, reduces cost, size of filter required, and improved overall inverter efficiency. Pulse width modulated voltage source inverter is preferred for high performance AC drives. The proposed control scheme and the result obtained by embedded simulations interfaced with STM32F4 microcontroller are presented and discussed. A simple hardware implementation is proposed and experimental results of SPWM based VSI are also shown. The Simulation results of the proposed scheme have excellent performance and compared with hardware results.

With the increasing focus on sustainable development and environmental preservation, the aviation industry has been exploring innovative solutions, such as more electric aircraft (MEA), to shape the future of air transportation. Among the various machines used in MEA, switched reluctance machines (SRMs) have gained significant attention due to their high reliability and excellent characteristics at high speeds. Delving into the forefront of SRM technologies, this article has summarized the advanced machine design, control strategies, fault diagnosis, and tolerant techniques, and the challenges of SRMs within the context of MEA. This article can provide resources for a deeper understanding of the latest developments in the technologies of SRM and help promote the application and development of SRM in the MEA field.

Optimal operation of a wind power generating system is featured by the variable-speed constant-frequency mode in which maximum-power capturing from the wind turbine and constant-frequency interfacing with the power system are the primary concerns. A slip power recovery system with a doubly excited wound rotor induction machine is attractive in this situation. Field orientation control for doubly excited induction machines is studied. Since the operational condition and control objectives of the variable-speed constant-frequency generating system are significantly different from those of a variable-speed drive system, the implementation strategy of field orientation control of induction machines must be reexamined. A stator field orientation control method suitable for the doubly excited induction machine in a wind power generating system is developed. Digital simulation was carried out showing that the doubly excited induction generator with the proposed control strategy can track the optimal torque-speed profile of a wind turbine very well. In addition, flexible reactive power control was also accomplished.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>