Dual Three-phase Research Articles

Modified SVPWM technique for CMV reduction in asymmetrical dual three phase induction machine drive

Due to its advantages, the asymmetrical dual three-phase induction motor drive is a strong choice in high-power applications. However, the common-mode voltage produced by the voltage source inverters affects the winding insulation and damages the bearings. Common-mode voltage is also responsible for electromagnetic interference and leakage currents. This paper, therefore, analyses the common-mode voltage produced by the inverter supplying a dual three-phase induction motor drive and proposes a novel modified space vector decomposition-based Space Vector Pulse Width Modulation (SVPWM) technique for common mode reduction. The vector space decomposition-based space vector modulation technique offers excellent flexibility as it reduces the common-mode voltage (CMV) by exploiting the additional degree of freedom in a dual three-phase system. The common-mode voltage (CMV) can be reduced to one-sixth of the DC link voltage compared to the highest CMV, i.e. half of the DC-link voltage produced in conventional space vector modulation. The proposed method is also validated experimentally to demonstrate the effectiveness of the proposed scheme in terms of the amplitude of CMV, pulsations, and total harmonic distortion(THD) in current.

Sensorless control of dual three-phase permanent magnet synchronous motor based on speed feedback and frequency-variable tracking.

The dual three-phase Permanent Magnet Synchronous Motor (PMSM) control system is characterized by its high reliability, slight torque fluctuation and low harmonic content. It is very suitable for systems requiring high power output and high reliability, for instance, electric vehicles, aerospace and military equipment. In this paper, a full speed domain sensorless control technology for dual three-phase PMSM is proposed which solves the limitations of other sensorless controls, improves system accuracy and stability, and has high practicality in fields such as new energy vehicles. The mathematical model of this motor in a static coordinate system is established, and the sine and cosine signals along with the velocity and angle information are obtained by using the flux linkage observer. Moreover, the estimated angle error parameter is introduced into the flux linkage observer; as a result, the estimation accuracy is improved by the estimated speed feedback, and the current frequency is tracked by the stator current Frequency-Variable Tracker (FVT) to reduce the current error. Meanwhile, to make the observer's estimation more accurate and to improve its ability to resist disturbance, a rotor disturbance is added to act as a disturbance variable. Through the mechanical motion equation of the motor, a fourth-order Extended State Observer (ESO) is built to calculate the rotor position and speed. Finally, the technology accuracy is verified using simulation and experimental results. The findings prove that the sensorless detection technology, with speed feedback introduce in this paper, has good reliability and high precision for dual three-phase PMSM under dynamic and static conditions.

Comparative Analysis of Noise and Vibration for Dual Three-Phase IPMSM Under Healthy and Multi-Phase Open-Circuit Fault Operations

The dual three-phase interior permanent magnet synchronous machines (IPMSMs) exhibit excellent fault-tolerant capabilities due to their multi-phase winding configurations. Under certain winding failure circumstances, by using the fault tolerant control (FTC) to reconstruct the normal rotating magnetomotive force, the machine can still provide the expected comparable torque as the healthy mode does. However, in the existing literature, limited attention was paid to the noise and vibration (NV) problems targeting the dual three-phase IPMSMs in FTC operation. To fill this knowledge gap, this paper conducts a quantitative comparison on the NV performance of a dual three-phase IPMSM under healthy and multi-phase open-circuit fault conditions under FTC. The comparative studies involve radial electromagnetic force, acceleration distribution, sound pressure level as well as machine housing deformation, which are analyzed under healthy and multi-phase open-circuit fault operations. Based on our exclusive findings, after applying the FTC, even though the machine can deliver the desired electromagnetic performance, the maximum deformation and sound pressure level of the IPMSM can be mitigated by 12.9% and 16.9%, respectively, compared to the ones under the faulty condition without FTC.

Disturbance-Free Operation of Dual Three-Phase PM Machine Under Open-Phase Fault Considering Harmonic Current Injection

Disturbance-Free Operation of Dual Three-Phase PM Machine Under Open-Phase Fault Considering Harmonic Current Injection

Position Sensorless Control of Dual Three-Phase IPMSM Drives With High-Frequency Square-Wave Voltage Injection

Dual three-phase interior permanent-magnet synchronous motor (IPMSM) drives have received more attention by the merits of better fault-tolerant capability and lower torque ripples. To improve the reliability of the system against failures in position sensor, it is necessary to investigate the position estimation method for dual three-phase IPMSM drives. The high-frequency (HF) signals injection is utilized for position estimation in three-phase IPMSM drives during low-speed operation region. However, the torque ripples are inevitable owing to the mixing of fundamental and HF components in the same control space for three-phase IPMSM drives. In this paper, the position sensorless control method has been proposed by injecting HF square-wave voltage in the harmonic subspace for the dual three-phase IPMSM drives. Since the harmonic subspace is decoupled from the torque subspace, the torque disturbance can be mitigated well with the proposed HF signal injection based position sensorless method. Moreover, the digital filters in signal extraction and current feedback can be avoided and the signal separation process becomes easy with the proposed method. The experiments have been conducted to validate the performance of the proposed method.

Finite-Time Control for Dual Three-Phase Hybrid Excitation Synchronous Machine Based on Torque Sensorless Current Coordinative Strategy

In this paper, the finite time speed regulation problem is investigated for a dual three-phase hybrid excitation synchronous machine (DTP-HESM) without a torque meter. The electromagnetic torque estimation required in the current coordinative strategy is obtained through the disturbance estimation technology. This method increases fault tolerance and reduces the cost as well as complexity of the DTP-HESM system. In contrast to the existing controllers in the speed loop, the non-singular terminal sliding mode control method is adopted to ensure the finite-time convergence of speed tracking in the whole speed region. To achieve better dynamic performance in the presence of lumped disturbances, including unknown load torque and unmodeled dynamics, the disturbance estimations are introduced into the sliding mode variable to establish a composite speed regulating controller. Simulations and experiments are carried out to validate the feasibility and effectiveness of the proposed control scheme.

Multi-amplitude voltage vector MPTC for dual three-phase PMSMs with low torque ripple

Multi-amplitude voltage vector MPTC for dual three-phase PMSMs with low torque ripple

H–H Configuration of Modular EV Powertrain System Based on the Dual Three-Phase BLDC Motor and Battery-Supercapacitor Power Supply System

A modular approach to the construction of electric machines, drive systems, power supply systems is a new direction of modern technology development. Especially, the modular approach is promising for electric vehicles due to such positive aspects as increased efficiency, fault tolerance, overall reliability, safety, enhanced control capabilities, etc. In this work, the modular approach is comprehensively applied to an EV powertrain system, which includes a dual three-phase (DTP) BLDC motor with two machine modules of an asymmetric configuration, two battery modules and a supercapacitor module (SCM). The proposed H–H configuration of modular EV powertrain system includes four voltage source inverters that combine the power modules with the open ends of the windings (OEW) of the module machine armature, and provide control of their operation. Based on the developed mode system of the OEW machine module operation for EV traction and braking, a general control algorithm for the proposed configuration of the modular EV powertrain system has been developed. It combines the control of the operating modes with the functions of maintaining the required SOC level of the SCM and equalizing the SOCs of the two battery modules. The conducted simulation and experimental studies confirmed the workability and effectiveness of the proposed solutions.

Multiple Sets of M-Phase Winding Composition Principle of Permanent-Magnet Machine for MMF Harmonic Analysis

This paper presents the composition factor of the fractional-slot permanent-magnet (PM) machine equipped with multiple sets of m-phase windings. Besides, the intrinsic relationship between magnet-motive force (MMF) harmonics and the phase shift angle is revealed. Firstly, the structural characteristics and phase shift regulations of multiple sets of <i>m</i>-phase windings are analyzed. Based on a single set of <i>m</i>-phase windings, the MMF composition factors of the odd and even sets of <i>m</i>-phase windings are derived, respectively. Secondly, four PM machines with different slot-pole combinations and winding configurations were designed. Their MMF harmonics are analyzed by the finite-element method to verify the analytical results. Moreover, the performances and MMF harmonics of a 48-slots 22-poles (48s22p) PM machine with dual three-phase windings are analyzed. Finally, the 48s22p machine is prototyped, and experimental results are validated.

SIMULATION AND EXPERIMENTAL INVESTIGATION OF DUAL THREE-PHASE BLDC MOTOR OPERATION AT IMBALANCED MODULAR LOADING

Electric machines built according to the modular principle – with several three-phase windings on a stator – are a new direction of modern electromechanics, because they have a number of advantages compared to traditional single-winding machines. Among these benefits, the most important are increased efficiency and fault tolerance, which is especially important for self-powered electric vehicles. However, the presence of a mutual magnetic coupling between the modules, as well as their unequal electrical load, amplify the electromagnetic torque ripple inherent in one or another electric drive system. In this work, the electromagnetic torque ripples in a dual three-phase (DTP) brushless DC motor (BLDCM) under different loads of its modules were investigated for the cases of absence and presence of mutual magnetic coupling between armature winding sets and in the cases of the drive operation in open and closed control systems. The research was carried out by means of simulation in the Matlab/Simulink environment on a circular model of real mock-up sample of DTP permanent magnet machine developed based on the results of its magnetic field simulation using the finite element method. Adequacy of simulation results is confirmed by experimental investigation. The results of the DTP BLDCM simulation studies showed an increase in the relative electromagnetic torque ripples of individual modules due to both the presence of magnetic coupling between winding sets and the deviation from their equal loading. However, at the level of the whole DTP BLDCM, a significant mutual compensation the electromagnetic torque ripples of the modules is shown, especially if they are magnetically coupled. The presence of closed-loop control systems of individual modules significantly reduces the electromagnetic torque ripples caused by different loading of the modules, especially in the case of magnetically uncoupled modules. References 26, figures 7, tables 3.

INDUCTIVE COUPLER FOR BATTERY CHARGING SYSTEM OF HEAVY ELECTRIC VEHICLES

This paper proposes a robust fault-tolerant control (FTC) for the dual three-phase (DTP) induction machines under failures controlled by a higher-order sliding mode control strategy. However, the DTP induction machine is increasingly used because of better reliability and a supply division. A passive and an active FTC law have been designed and tested on DTP. The proposed method not only realizes the FTC and the fault elimination but also provides a possible solution for emulating a traction system using a direct continue machine (DCM) supplied by a four-quadrant chopper. Therefore, the emulation system is based on a controlled DCM, which imposes the same behavior of the mechanical power train of an electric vehicle to the DTP. Simulation results are given to verify the robustness and good performance of the proposed fault-tolerant control scheme.

NONLINEAR FAULT TOLERANT CONTROL OF DUAL THREE-PHASE INDUCTION MACHINES BASED ELECTRIC VEHICLES

This paper proposes a robust fault-tolerant control (FTC) for the dual three-phase (DTP) induction machines under failures and which is controlled by a higher-order sliding mode control strategy. However, the DTP induction machine is increasingly used because of its advantages such as better reliability and supply division, both passive and active FTC laws have been designed and tested on DTP. The proposed method not only realizes the FTC and the fault elimination as well but also provides a possible solution for emulating a traction system using a direct continue machine (DCM) supplied by a four-quadrant chopper. Therefore, the emulation system is based on a controlled DCM, which imposes the same behavior of the mechanical power train of an electric vehicle to the DTP. Simulation results are given to verify the robustness and good performance of the proposed fault-tolerant control scheme.

Model-Free Predictive Current and Disturbance Rejection Control of Dual Three-Phase PMSM Drives Using Optimal Virtual Vector Modulation

Model-based predictive current control (MBPCC) relies heavily on adequate system modeling and accurate parameters. The detailed models of dual three-phase permanent magnet synchronous motors (PMSMs) contain mutual cross-coupling dynamics which make it difficult to extract accurate parameters. Also, some of the physical parameters of PMSMs are generally nonlinear functions of current and rotor position. In this article, a model-free predictive current control (MFPCC) based on an ultralocal model and an extended state observer is proposed for an asymmetrical dual three-phase (ADTP) PMSM. The MFPCC method is shown to provide superior current regulation when compared to the standard MBPCC approach under uncertain parameter conditions. Furthermore, the harmonic currents and the current ripple in the ADTP PMSM drive have been regulated to near-zero values by using optimized voltage vectors comprised of virtual vectors and null vectors. A generalized center-aligned pulsewidth modulation (PWM) scheme is presented to facilitate the synthesis of the optimal virtual voltage vectors for implementation on a low-cost digital signal processing platform. The performance improvements of the MFPCC with optimal virtual vector modulation are verified and compared with the conventional MBPCC method in both simulations and experiments on a surface-mount type dual three-phase PMSM.

Fundamental PWM Excitation Based Rotor Position Estimation for a Dual Three-Phase Permanent Magnet Synchronous Machine

Two rotor position estimation methods for a dual three-phase (DTP) permanent magnet synchronous machine (PMSM) are investigated in this article, where the rotor position is estimated by exploiting the saliency of the motor through the phase current derivative measurement during the fundamental PWM excitation of a standard six-phase two-level inverter. It is found that in a DTP PMSM, the wide speed range rotor position estimation is possible not only in the torque-producing subspace, but also in the harmonic subspace. The principle and practical implementation of the methods are explained in details. The experimental results verify the effectiveness of the proposed rotor position estimation methods.

Redesign of common dc-link capacitors for dual-three phase machine drive system based on PWM sequence reorder

The dual three phase machine drive system with the common dc-link capacitors has been widely used in many industrial applications due to the advantages such as small stallion volume, reduced cost and flexibility. The large ripple current caused by the pulse width modulation (PWM) switching has to be reduced by choosing the large capacitor, while the bulky dc-link capacitor is still the main drawback for the improvement of power density. Therefore, this paper proposes a common dc-link capacitors reduced design method for dual three phase machine drives system with the proposed PWM sequence reorder aiming at the cost, volume and lifetime. First, the derived dc-link current expression are given according to the phase current and average current. Secondly, the PWM sequence reorder method on two inverters is used to reduce the dc-link capacitors switching frequency harmonics. Finally, the design principle of the new capacitors is proposed considering the cost, volume, lifetime. The results show that the lifetime of the capacitors with the proposed reorder PWM method can be extended significantly. The experiment results are given to verify the effectively of the proposed method. The results could provide a good guideline for the dual-three phase drive system design with low cost and high reliability.

Optimal switching sequence control for current stress reduction of DC-link capacitors in dual-three phase PMSM drives

The safety and installation space of DC-link capacitor is crucial for dual-three phase permanent magnet synchronous machines (DTPMSM) drives in industrial applications. Reducing the capacitor current stress can contribute to decrease the designed capacitor value and install size, thus enhance safety of drives fed by two parallel inverters. Therefore, an optimal switching sequence control scheme for DTPMSM drives is proposed to reduce the DC-link capacitor current stress in this paper. For DTPMSM drives, the maximum four adjacent voltage vectors control (MFAVC) method is usually adopted due to its control flexible and stability characteristic. Based on MFAVC, the capacitor current can be derived though the current reconstruction theory to reorder the current amplitude over one switching period. Through the rearrangement of voltage vector and duration, the theoretical analysis of capacitor current reduction is presented. On this basis, the optimal switching sequence control method can be implemented based on the minimized current sum of the two inverters. The performance of proposed method has been evaluated via. comparatively experimental tests on a prototype 3 kW DTPMSM drive, which shows superior features on reducing capacitor current stress. Furthermore, it is also found that the proposed method is helpful to redesign a small capacitor value for DTPMSM drives.

Sequential Subspace Optimization Design of a Dual Three-Phase Permanent Magnet Synchronous Hub Motor Based on NSGA III

The multiobjective optimization design of dual three-phase permanent magnet synchronous hub motors (PMSHMs) is challenging due to the high dimension and huge computation cost of finite-element analysis (FEA). A new multiobjective optimization strategy is proposed for dual three-phase PMSHMs in this article. All design parameters are divided into two subspaces according to the Pearson sensitivity analysis results to improve optimization efficiency. A new training method is adopted to improve the accuracy of the approximate model. By improving a multiobjective intelligent optimization algorithm, nondominated sorting genetic algorithm (NSGA) III, a new algorithm is proposed, which will greatly shorten optimization time. It is found that the proposed optimization method can significantly improve the performance, such as smaller torque ripple and higher maximum torque for the investigated PMSHM, while the computation resources are reduced. A prototype based on the optimization results is manufactured, and experiments are conducted on the platform to verify the accuracy of the optimization results and the FEA. The effectiveness of optimization and the accuracy of the simulation are verified by the experimental results.

Comprehensive Investigation of Space-Vector PWM Including Novel Switching Sequences for Dual Three-Phase Motor Drives

The increasing interest in dual three-phase motor drives has led to the corresponding research on pulsewidth modulation (PWM) techniques. Compared to carrier-based PWM (CPWM), space-vector PWM (SVPWM) attracts more attention because of clear physical meaning and high design flexibility. However, it is difficult to design the method from the space-vector concept due to the complexity in the selection and the arrangement of the space vectors. In this article, with the unified comprehension of the space-vector and carrier-based approaches to PWM, a straightforward approach is proposed to develop various switching sequences. As a result, a total of ten different switching sequences are presented, including five novel switching sequences. In addition, the time distribution schemes of the applied vectors for the derived switching sequences are explored to obtain the acceptable harmonic performance with low computation burden. With the benefit of the derived switching sequences, a comprehensive investigation on the design of PWM methods can be carried out. As a result, an SVPWM method using five active vectors is proposed with excellent harmonic performance. Simulation and experimental results on a 7.5-kW dual three-phase induction motor drive are given to confirm the correctness of the theoretical analysis and the validity of the proposed method.

Development of a smart hybrid drive system with advanced logistics for railway applications

Fuel Hydrogen cells become nowadays a major candidate to replace the diesel in powering the traction locomotives since they offer low emission of pollutant gases, high efficiency, and flexible modular structure without the need for installation of electrification infrastructure for railway networks. However, they cannot respond appropriately to the fast load transients due to their slow internal electrochemical and thermodynamic responses. Therefore, they shall be integrated with fast dynamics Li-ion battery cells to form a hybrid power source for traction systems. Accordingly, this paper presents a development of a new smart integrated power source of fuel hydrogen and Li-ion battery cells to supply dual three-phase machines for driving the trains in railway networks. The developed control management system is regulating the two power sources according to the train operational modes as well as the battery state of charge. In addition to that, dual three-phase machines offer several superiorities over the conventional three-phase machines such as lower harmonic distortion and power losses along with higher power density and fault tolerance. A designated railway line is nominated through selection criteria in this paper for the implementation of the new smart drive traction system in HIL platform using Typhoon HIL real time simulator. Moreover, an optimization analysis has been carried out to reduce the overall hydrogen consumption with the same journey time spent for a designated railway line using particle swarm optimization approach. Finally, a case study is presented to illustrate a proof of concept for designing the hydrogen refueling station for such railways which are supplied by the new integrated power source of fuel hydrogen and Li-ion battery cells. The case study investigates the site selection, operational assessment, and equipment requirements.

Interleaving Modulation Schemes in Asymmetrical Dual Three-Phase Machines for the DC-Link Stress Reduction

The DC-Link capacitor plays a crucial role as far as power density and reliability are concerned: it occupies approximately 40% of the inverter, and causes approximately 30% of its failures. Asymmetrical dual three-phase (ADTP) multiphase arrangements are gaining relevance in the automotive sector for powertrain applications. This work focuses on reducing the impact that the widely used double zero sequence injection (DZSI) family of PWM techniques have on such a bulky and failure-prone component in an ADTP arrangement by means of interleaving techniques. By using the double Fourier integral formalism, the input current spectra and the overall performance of these PWM techniques have been derived, in terms of current rms value and voltage ripple in the DC-Link capacitor. Simulations have shown that choosing an adequate interleaving scheme and angle considerably relieves both current and voltage stresses on the DC-Link capacitor compared to noninterleaved operation. Reductions of 84% current rms and 86% voltage ripple have been achieved at static operating points. Finally, by averaging the rms current over WLTP standard driving cycle, reductions up to 26% have been obtained under more realistic conditions. All this would enhance the reliability and reduce the size of the onboard capacitors in future electric vehicles.