Advanced Electrical Machines and Drives Technologies

In this paper, we present an analysis of the properties of the prototype three-phase Multichannel Permanent Magnet Synchronous Generator (MCPMSG) prototype designed and constructed by the authors. Each channel of the generator has electrically separated windings, which allows us to create an island system of electricity generation. The analyzed MCPMSG is intended for critical applications, and it is designed for four-channel operation. The purpose of this work is to analyze various configurations of the generator channels to improve the redundancy of the electricity generation system. The MCPMSG operation with one or two independent sources of energy consumption in the case of a dual-channel or double dual-channel operation was investigated. For the analyzed cases, the original mathematical models of the three-phase MCPMSG were developed. On the basis of numerical and laboratory tests, the influence of individual configurations on the MCPMSG output parameters was determined. An original method for diagnosing the operation of the MCPMSG channels was developed. Numerical and laboratory tests of the proposed diagnostic method based on a single voltage signal were carried out. As part of the laboratory tests, selected operating states under conditions of full winding symmetry and internal asymmetry were analyzed. The advantage of the proposed diagnostic method is the control of the operating state of the channels both under load and in the de-energized state. The proposed diagnostic method for control of the individual channel requires measurement of only one voltage signal. Full article

In this paper, a single-phase BLDC motor is applied to a cooling fan motor and a Drive IC integration analysis method of the single-phase BLDC motor is proposed. Single-phase BLDC motors have a simple structure, are easy to manufacture, and are low cost, so they are used in applications where low outputs and low costs are advantageous. Single-phase BLDC motors use a full-bridge inverter (Drive IC), and this inverter (Drive IC) has dead time due to switching. Therefore, in order to consider dead time when analyzing a single-phase BLDC motor, analysis through integration with Drive IC is necessary. This paper compares the types of single-phase BLDC motors, designs a model that satisfies target performance, and conducts research on Drive IC integration analysis through FEA. A prototype motor was manufactured and tested, and the validity of the Drive IC integration analysis was verified. Full article

This paper proposes a design method to reduce cogging torque and torque ripple in the concentrated winding of IPMSMs (Interior Permanent Magnet Synchronous Motors) used in motors for the semiconductor ETCH process. IPMSMs can utilize reluctance torque through the difference in inductance between the d axis and q axis, but they are at a disadvantage in terms of reducing cogging torque while tapering the rotor and stator to reduce torque ripple. In addition, the existing single tapering can push the permanent magnets into the rotor. If the rotor’s permanent magnets are embedded, the magnetic reluctance will increase, and the overall performance of the motor will decrease. However, an optimum design method was derived in which the magnets do not move during rotor tapering. This geometric design is an optimum design method that reduces cogging torque and torque ripple. This paper compares and analyzes four models, the concentrated winding model, distributed winding model, conventional tapering model, and separated tapering model, using 2D and 3D finite element analysis (FEA). Full article

Due to the high cost and the predicted shortage of rare earth elements in the near future, the task of developing energy-efficient electric machines without rare earth magnets is of great importance. This article presents a comparative analysis of optimized designs of a ferrite-assisted synchronous reluctance machine (FaSynRM) and a ferrite-assisted synchronous homopolar machine (FaSHM) in a 370-kW subway train drive. The objectives of optimizing these traction machines are to reduce their losses, maximum armature current, and torque ripple. The optimization considers the characteristics of the machines in the subway train moving cycle. The problem of the risk of irreversible demagnetization of ferrites in the FaSynRM and FaSHM is also considered. To reduce the computational burden, the Nelder-Mead method is used for the optimization. It is shown that the FaSHM demonstrates better field weakening capability, which can reduce the maximum current, power, and cost of the inverter power modules. At the same time, the FaSynRM requires less permanent magnet mass for the same torque density and is more resistant to irreversible demagnetization, which can reduce costs and improve the reliability of the electric machine. Full article

In previous research, a bionic hydraulic pipeline (BHP) with a three-layer structure for absorbing pulsation was invented. This paper proposes to disperse single-walled carbon nanotubes (SWCNTs) in the elastic layer material, namely silicone rubber (RTV), to enhance its ability to absorb pulsation. Firstly, the RTV-SWCNTs composite specimens with different SWCNT proportions are prepared and tested. It was found that the mechanical property is optimal when the volume content of the SWCNTs is 0.5 vol%. On this basis, BHPs with RTV-SWCNTs composite material as the elastic layer are fabricated to study the influence of the thickness and length of the elastic layer on the absorption flow pulsation. The results show that the addition of SWCNTs significantly improves the mechanical properties of silicone rubber and reduces the friction between the elastic material and oil, so that the BHP can absorb the pressure pulsation better. With the appropriate thickness and length of the elastic layer, the addition of SWCNTs can increase the pulsation suppression effect by 20%. Moreover, to analyze the influence of nanomaterials on pipeline friction, a comprehensive fourteen-equation model for describing the fluid–structure interaction (FSI) of the pipe conveying fluid considering friction coupling is established. And through numerical analysis and modal tests, the evaluation error for the modified dynamic model of the BHP is less than 5%, verifying the correctness of the proposed model and solution method. Full article

An SMR (small modular reactor) is expected to be able to operate flexibly in conjunction with a high renewable energy penetration grid as a result of improved safety and easy power control compared to large nuclear power plants. SMRs, such as South Korea’s System-integrated Modular Advanced ReacTor (SMART), are designed to use canned motors (CMs) for their reactor coolant pumps (RCPs) to enhance their safety. CMs passively enhance the reactor’s safety by preventing the leakage of radioactive reactor coolant. However, with motor sizes designed to be as small as possible, and the increased air gap of CMs between the stator and rotor, the starting torque may be insufficiently low compared to that of similar-sized induction motors (IMs). Thus, CMs may require variable frequency drives (VFDs) to start. This paper compares the torque characteristics of CMs with those of IMs for SMART’s RCPs. ETAP is then used to perform a motor-starting analysis for CMs activated with and without VFDs. The results are presented and analyzed to find out if VFDs can deal with the CM starting torque issue. Full article

An intelligent servo drive system for a permanent magnet-assisted synchronous reluctance motor (PMASynRM) that can adapt to the control requirements considering the motor’s nonlinear and time-varying natures is developed in this study. A recurrent wavelet fuzzy neural network (RWFNN) with intelligent backstepping control is proposed to achieve this. In this study, first, a maximum torque per ampere (MTPA) controlled PMASynRM servo drive is introduced. A lookup table (LUT) is created, which is based on finite element analysis (FEA) results by using ANSYS Maxwell-2D dynamic model to determine the current angle command of the MTPA. Next, a backstepping control (BSC) system is created to accurately follow the desired position in the PMASynRM servo drive system while maintaining robust control characteristics. However, designing an efficient BSC for practical applications becomes challenging due to the lack of prior uncertainty information. To overcome this challenge, this study introduces an RWFNN as an approximation for the BSC, aiming to alleviate the limitations of the traditional BSC approach. An enhanced adaptive compensator is also incorporated into the RWFNN to handle potential approximation errors effectively. In addition, to ensure the stability of the RWFNN, the Lyapunov stability method is employed to develop online learning algorithms for the RWFNN and to guarantee its asymptotic stability. The proposed intelligent backstepping control with recurrent wavelet fuzzy neural network (IBSCRWFNN) demonstrates remarkable effectiveness and robustness in controlling the PMASynRM servo drive, as evidenced by the experimental results. Full article

The aim of this paper is to present our research into the reduction of vibrations in induction motors. The use of power inverters results in the generation of electrical harmonics, which increase the level of the mechanical vibrations of electrical machines. To reduce these harmonics, we present a discontinuous pulse-width modulation (PWM) control strategy based on carrier-wave modulation applied to multilevel inverters. Using the proposed modulation technique, the amplitude of the electrical harmonics is reduced, as compared to other conventional techniques. These current harmonics produce the MMF (magnetomotive force) harmonics in the air gap, which are one of the main sources of vibrations. The control strategy makes it possible to vary the electrical spectrum at the output of a multilevel inverter by modifying a control parameter of the carrier wave in the PWM, thus avoiding the natural frequencies of mechanical resonance. The proposed technique also has the feature of attenuating the total harmonics distortion of the voltage of the multilevel inverters, as well as the achievement of a higher RMS value of the output voltage for the same DC level. Laboratory results for an induction motor with different modulation strategies, applied in a multilevel inverter and compared to the strategy presented, are attached. Full article

Line-start permanent magnet synchronous motors (LSPMSMs) are of great interest to researchers because of their high energy efficiency, due to the growing interest of manufacturers in energy-efficient units. However, LSPMSMs face some difficulties in starting and synchronization processes. The LSPMSM lumped parameter model is applicable to estimating the successfulness of starting and further synchronization. The parameters of such a model can be determined using computer-aided identification algorithms applied to real motor transient processes’ curves. This problem demands significant computational time. A comparison between two algorithms, differential evolution and Nelder–Mead, is presented in this article. The algorithms were used for 0.55 kW, 1500 rpm LSPMSM parameter identification. Moreover, to increase computational speed, it is proposed to stop and restart the algorithms’ procedures, changing their parameters after a certain number of iterations. A significant advantage of the Nelder–Mead algorithm is shown for the solving of the considered problem. Full article

This research introduces a cost-effective converter for single-phase machines, aiming to enhance efficiency and reduce energy consumption in retrofit applications. Single-phase motors commonly found in household appliances often suffer from low efficiency, resulting in wasted energy. To tackle this problem, a dedicated converter was proposed to replace the existing capacitors and improve the motor performance. This study presents a proof of concept for retrofit applications, discussing the converter design methodology and prototype evaluation. Additionally, a cost analysis comparing single-phase and three-phase motors is included. It aims to demonstrate the long-term cost savings and improved energy efficiency of the proposed converter. The findings highlight the converter’s potential as a promising solution for enhancing energy efficiency and decreasing costs in single-phase motor applications. Full article

The analyses of the influence of spatial harmonics on the electromagnetic torque of the multi-phase induction machine and reducing this influence are important tasks to ensure the high efficiency of the induction machine. Designing the machine to consider the influence of spatial harmonics is essential to ensure the desired mechanical and energy characteristics. In the case of the sinusoidal winding supply of the induction machine, the magnetomotive force has high spatial harmonics, which are caused by the machine-winding design. The interaction between the 5th, 7th, 11th and 13th spatial harmonics of the winding function and the first time-harmonic of the winding supply causes the appearance of the 6th and 12th harmonics in the electromagnetic torque of the machine. A prototype of the symmetrical six-phase induction machine and the experimental study for the influence of spatial harmonics on the harmonic content of the stator currents in different machine modes are given in this paper. The mathematical model of the six-phase induction machine has been developed using the average voltages in integration step method. The introduction of the harmonic components into the magnetization inductance in the mathematical model of the six-phase induction machine for taking into account the spatial harmonics of the machine-winding function is proposed in this paper. The adequacy of the mathematical model was confirmed by comparing the simulation and experimental results. The harmonic content of the electromagnetic torque, which is caused by spatial harmonic influence, is analyzed. Full article

There is a trend to go towards low gear-ratio or even direct-drive actuators in novel robotic applications in which high-torque density electric motors are required. The Yokeless and Segmented Armature Axial Flux Permanent Magnet Synchronous Machine is therefore considered in this work. In these applications, the motors should be capable to deliver high torque at standstill for long periods of time. This can cause overheating of the motors due to a concentration of the losses in a single phase; hence, it becomes necessary to derate the motor torque. In this work the influence of the slot/pole combination, the addition of a thermal end-winding interconnection and the equivalent thermal conductivity of the winding body on the torque performance at standstill will be studied both experimentally via temperature measurements on a prototype stator, and via a calibrated 3D thermal Finite Element model. It was found that both a good choice of the slot/pole combination and the addition of a thermal end-winding interconnection have a significant influence on the torque performance at standstill, and allow up to 8% increase in torque at standstill in comparison to a reference design. Full article

The safety of direct torque control (DTC) is strongly reliant on the accuracy and consistency of sensor measurement data. A fault-tolerant control paradigm based on a dual-torque model is proposed in this study. By introducing the vector product and scalar product of the stator flux and stator current vector, a new state variable is selected to derive a new dual-torque model of induction motor; it is combined with a current observer to propose a dual-torque model fault-tolerant control method. This technology calculates torque and reactive torque directly, reducing the system’s reliance on sensors, avoiding sensor-noise interference, and improving torque response speed while suppressing torque ripple. In addition, to improve system dependability and safety, a fault-tolerant control method is devised by combining the model with an adaptive virtual current observer. Ultimately, experiments validate the suggested method’s effectiveness and feasibility. Full article

Cryogenic cooling is a well-established and expanding technology. In the field of electric machines, it allows the construction of more efficient machines with a high power density. This paper addresses the main cooling technologies and their impact on cryogenic machine construction, providing perspective for their use in future electrical machines. Although cost and safety issues of cryogenic systems are still holding back the uptake of cryogenic electric motors and generators, research in this field should provide significant improvements and promote their use at different levels. Full article

Electric machines with hybrid excitation have increased torque density while maintaining a wide range of speed control. This article presents the results of the optimal design of a synchronous homopolar generator (SHG) with ferrite magnets on the rotor and excitation winding on the stator for passenger cars. The use of ferrite magnets on the rotor of a synchronous homopolar generator makes it possible to use the stator surface more efficiently, which in turn increases energy efficiency and reduces the dimensions of the generator. At the same time, the excitation winding on the stator provides a reliable brushless design and the ability to control the excitation flux. The problem of long-time calculation of the three-dimensional SHG structure, which is especially relevant when using multi-iterative computer optimization, is solved by using the computationally efficient Nelder-Mead method and a simplified SHG model using two-dimensional finite element analysis. It is also clear that the low torque ripple of SHG with ferrite magnets with two stator-rotor stack combinations (SRSC) is largely provided by the fact that the torque ripples of individual SRSCs are in antiphase. The problem of considering the magnetic properties of magnetic core sections made of structural low-carbon steel is discussed. It has been found that with an increase in both the saturation level of the magnetic circuit and the magnetomotive force (MMF) of the SHG excitation winding, resistance to irreversible demagnetization of ferrite magnets on the rotor can be increased by increasing their height. In addition, it is shown that there is a significant increase in performance when using the hybrid excitation, in comparison with the conventional SHG design without magnets. Full article

The analysis and calculation of the armature electromagnetic force is the premise of studying the dynamic characteristics of the electromagnetic railgun. Aiming at the problem of the numerical solution “pseudo-oscillation” at high speed, an extrapolation prediction method of armature electromagnetic force based on the Deep Belief Network-Deep Neural Network (DBN-DNN) is proposed. Firstly, the electromagnetic field control equation and armature dynamics equation, considering the influence of armature movement, are given, and the finite element simulation model of the electromagnetic railgun is established to analyze the dynamic characteristics and numerical solution stability of the armature electromagnetic force. Then, based on the stable numerical simulation data under different armature conductivities, a DBN-DNN method is proposed to realize the extrapolation prediction of the armature electromagnetic force under the standard conductance. Finally, the extrapolation prediction performance of the proposed method is tested by two electromagnetic railgun cases. Additionally, we further propose the training strategy of DBN-DNN parameters from solving armature electromagnetic force at low conductivity to standard conductivity. The armature electromagnetic force extrapolation prediction method for the whole launch process from low speed to high speed provides a new idea for the dynamic characteristic analysis of the high-speed electromagnetic railgun. Full article

This paper investigates a cup-rotor permanent-magnet doubly fed machine (CRPM-DFM) for extended-range electric vehicles (EREVs). The topology and operating principle of the powertrain system based on CRPM-DFM are introduced. Then, the mathematical model of CRPM-DFM is established and the feedback linearization control of CRPM-DFM is given to realize the decoupling control of flux and torque. Moreover, the torque characteristic of CRPM-DFM is analyzed and the load torque boundaries with sinusoidal steady-state solution of CRPM-DFM is deduced. In addition, the MTPA control is derived to improve the efficiency of CRPM-DFM, and the efficiency of CRPM-DFM regarding various operating modes is investigated. Furthermore, the speed optimization strategy of ICE is proposed to reduce fuel consumption. Finally, the driving performance and fuel economy of the powertrain system are verified by simulation. Full article

Pumping systems play a fundamental role in many applications. One of the applications in which these systems are very important is to pump water. However, in the real world context, the use of renewable energies to supply this kind of system becomes essential. Thus, this paper proposes a water pumping system powered by a photovoltaic (PV) generator. In addition, due to its interesting characteristics, such low manufacturing cost, free of rare-earth elements, simple design and robustness for pumping systems, a switched reluctance motor (SRM) is used. The power electronic system to be used in the PV generator and to control the SRM consists of a DC/DC converter with a bipolar output and a multilevel converter. The adopted DC/DC converter uses only one switch, so its topology can be considered as a derivation of the combination of a Zeta converter with a buck–boost converter. Another important aspect is that this converter allows continuous input current, which is desirable for PV panels. The topology selected to control the SRM is a multilevel converter. This proposed topology was adopted with the purpose of reducing the number of power semiconductors. A maximum power point algorithm (MPPT) associated with the DC/DC converter to obtain the maximum power of the PV panels is also proposed. This MPPT will be developed based on the concept of the time derivative of the power and voltage. It will be verified that with the increase in solar irradiance, the generated power will also increase. From this particular case study, it will be verified that changes in the irradiance from 1000 W/m² to 400 W/m² will correspond to a change in the motor speed from 1220 rpm to 170 rpm. The characteristics and operation of the proposed system will be verified through several simulation and experimental studies. Full article

In this paper, a discrete skew methodology is presented to understand the effect of skewing angle on electromagnetic torque in SynRM design. A new approach is proposed to estimate the amplitude of each torque ripple component as a function of skewing angle. The reduction factor for each harmonic component is derived in general form, allowing for the determination of overall torque ripple waveform. The validity of the proposed method is evaluated through the examination of two SynRMs, resulting in a torque ripple reduction of up to 70%. The results obtained through the use of a proposed analytical ripple reduction estimator and FEA evaluation showed good agreement. The proposed skewing technique was applied on a previously optimized triple-barrier SynRM with a positive outcome: a consistent torque ripple reduction tackling relevant harmonic components. The analysis of harmonic distribution of torque ripple is mandatory for the selection of the optimal skewing strategy when following the proposed method, with two-step skewing recommended for mostly-purely-sinusoidal torque waveforms, and multi-step skewing recommended for machines with multiple higher-magnitude harmonic components. Full article

This paper describes a method for reducing the common-mode voltage in a seven-phase brushless DC motor (BLDC) drive. The conventional interleaved method used in the three-phase inverter system is extended and applied. The proposed phase-phase interleaved method is studied to apply the six-phase excitation method for controlling the seven-phase BLDC. The six-phase switching functions related with modulation index (MI) and interleaved angle are obtained, and the average of the common-mode voltage is derived mathematically. The proposed control method reduces the common-mode voltage generation by applying the optimal interleaved angle according to MI. The proposed method is verified by experimental results. Full article

In this paper, the collaboration of a GlidArc-type plasma reactor with four dedicated power supplies was analysed. Each power supply is characterised by a different design solution. Plasma generation by electrical discharge requires a careful analysis of the power supply design, its operating characteristics, currents, voltages and frequencies. Although the power supplies tested have similar abilities and provide similar power supply parameters, different plasma reactor performance characteristics are obtained for each of them. The results indicate that some power supply parameters were overestimated or underestimated at the design stage. Some of the power supplies tested under plasma reactor load also show poor interaction with the mains. The interaction of the power supplies with the plasma reactor and the mains supply is strongly influenced by the type of plasma gas. Analyses indicate that an optimally designed power supply should combine the solutions contained in each of the power supplies tested. Full article

When a permanent magnet synchronous motor (PMSM) is designed according to the traditional motor design theory, the performance of the motor is often challenging to achieve the desired goal, and further optimization of the motor design parameters is usually required. However, the motor is a strongly coupled, non-linear, multivariate complex system, and it is a challenge to optimize the motor by traditional optimization methods. It needs to rely on reliable surrogate models and optimization algorithms to improve the performance of the PMSM, which is one of the problematic aspects of motor optimization. Therefore, this paper proposes a strategy based on a combination of a high-precision combined surrogate model and the optimization method to optimize the stator and rotor structures of interior PMSM (IPMSM). First, the variables were classified into two layers with high and low sensitivity based on the comprehensive parameter sensitivity analysis. Then, Latin hypercube sampling (LHS) is used to obtain sample points for highly sensitive variables, and various methods are employed to construct surrogate models for variables. Each optimization target is based on the acquired sample points, from which the most accurate combined surrogate model is selected and combined with non-dominated ranking genetic algorithm-II (NSGA-II) to find the best. After optimizing the high-sensitivity variables, a new finite element model (FEM) is built, and the Taguchi method is used to optimize the low-sensitivity variables. Finally, finite element analysis (FEA) was adopted to compare the performance of the initial model and the optimized ones of the IPMSM. The results showed that the performance of the optimized motor is improved to prove the effectiveness and reliability of the proposed method. Full article

The article presents the optimal design of a 35 kW brushless synchronous homopolar generator without permanent magnets for railway passenger cars. The excitation winding of the generator is located on the stator, and the toothed rotor has no windings. The generator characteristics are optimized considering the required constant power speed range. A single-objective Nelder–Mead algorithm and 2D Finite Element Analysis were used for the optimization. As a result of the optimization, power losses are significantly reduced over the entire operating range of the generator rotational speed, the current capacity of the solid-state rectifier, and the torque ripple. A comparison of the calculated characteristics of the generator under consideration with the characteristics of a commercially available undercar generator shows that the active volume is reduced by a factor of 2.1, and the losses are significantly reduced over the entire operating speed range. Full article

A total artificial heart (TAH) represents a challenge in medical science to provide a survival perspective for patients with severe cardiac problems. Although cardiac transplantation represents the optimal therapeutic solution for end-stage heart failure, its application is limited by organ shortages. However, innovative technologies that can fit the operation and constraints of a physical heart are now under experimentation, making the target of a reliable and minimally invasive TAH much closer. The electromagnetic devices involved in system supply and actuation could potentially improve patient quality of life and expectancy. The purpose of this paper is to provide an overview of the operating principle, ratings, and key performance of the main electromagnetic components, with a particular focus on actuators that emulate the pumping effect of the heart ventricles. Linear oscillating actuators are very promising for their compactness and straightforward integration; therefore, an exhaustive overview considering both the single and the dual-mover configurations is worth being carried out. Taking a cue on the projects under development and after a detailed literature investigation, the pros and cons of the different solutions are discussed with the purpose of providing a critical analysis of the state-of-the-art. Full article

High torque ripple dramatically affects the switched reluctance motor (SRM) application. To reduce the torque ripple, a reference torque neural network (RTNN) is proposed to adjust the reference torque online. Firstly, the RTNN is built on the torque sharing function (TSF) method. Furthermore, the RTNN is designed as a single-input and -output network. As the periodic relationship between the torque ripple and the rotor angle, the rotor angle constitutes the central node parameter of the implicit function in RTNN. Therefore, one-step adjustment of the RTNN can perform well at restraining reference torque. Lastly, the torque error is used to adjust the parameters of RTNN to reduce the torque ripple. In the MATLAB environment, through the simulation comparison with fuzzy torque and PD current compensation method, the effectiveness of RTNN at torque ripple suppression is proven with different loads and speeds. Full article

The traditional sensorless control system of permanent magnet synchronous motor (PMSM) has the problems of low estimation accuracy and poor anti-interference ability. Moreover, the position estimation performance is subjected to position harmonic ripples caused by inverter nonlinearities and flux spatial harmonics. To optimize the dynamic performance of the PMSM sensorless control system, this paper proposes a sensorless control scheme that combines integral backstepping control with enhanced linear extended state observer (ELESO). The ELESO consists of two linear extended state observers (LESOs), which estimate the internal and external disturbances of the system, to improve the estimation accuracy of rotor position. Then, the integral backstepping controller processes the estimated rotor position and speed information to obtain d and q-axis voltages. The sensorless control scheme is implemented in the Matlab/Simulink and verified by experiments. The simulation and experiment show that the scheme can effectively suppress load interference and improve control accuracy. Full article

This study attempted to establish an optimal design and perform dynamic analysis for a spring-actuated cam-linkage composite mechanism in a rated 12 kV, 25 kA vacuum circuit breaker (VCB). The optimal design of the VCB mechanism involves two steps: the first step involves the optimal design of the stiffness of closing springs and the cam profile, based on three-order polynomial motion curve of the follower; the second step involves the optimal design of a four-bar linkage. To minimize the surplus work in the VCB operating mechanism, the overall difference between the general output force and general resistant force of the VCB operating mechanism during the closing operation was adopted as the objective function to be minimized. Furthermore, the differential evolution algorithm with the golden ratio (DE-gr), an efficient and accuracy metaheuristic algorithm, was employed as the optimization method. The dynamic analysis of the optimal operating mechanism was conducted using a MATLAB-coded program and verified by the multibody dynamic software MSC-ADAMS. The dynamic analysis revealed that the optimal design of the VCB mechanism can considerably decrease the average closing velocity of the movable contact and the Hertz stress between the contact surface of the cam and the roller follower. Full article

In the European Union (EU), road transport contributes a major proportion of the total greenhouse gas (GHG) emissions, of which a significant amount is caused by heavy-duty commercial vehicles (CV). The increasing number of emission regulations and penalties by the EU have forced commercial vehicle manufacturers to investigate powertrain technologies other than conventional internal combustion engines (ICE). Since vehicle economics plays an important role in purchase decisions and the powertrain of a battery electric vehicle (BEV) contributes to about 8–20% of the total vehicle cost and the electric machine (EM) alone contributes to 33–43% of the drivetrain cost, it is necessary to analyze suitable EM topologies for the powertrain. In this paper, the authors aim to analyze the technical and cost aspects of an EM for electric commercial vehicles (ECV). Based on prior research and literature on this subject, an appropriate methodology for selecting suitable geometrical parameters of an e-machine for the use case of a heavy-duty vehicle is developed using MATLAB and Simulink tools. Then, for the economic analysis of the e-machine, reference ones are used, and their design parameters and cost structures are utilized to develop a cost function. Different use cases are evaluated according to the vehicle’s application. The results for a use case are compared by varying the design parameters to find the most cost-effective EM. Later, an analysis is performed on other decisive factors for EM selection. This highlights the importance of collaborative consideration of technological as well as the economic aspects of EMs for different use cases in ECVs. The method developed in this work contributes to understand the economic aspect of EMs as well as considering their performance factors. State-of-the-art methods and research are used to develop a novel methodology that helps with the selection of the initial geometry of the electric motor during the design process, which can serve to aid future designers and converters of electric heavy-duty vehicles. Full article

The interior permanent magnet synchronous machine (IPMSM) has been widely used in industrial applications due to its several favorable advantages. To further improve the machine performance, an improved nonlinear predictive controller for the IPMSM is proposed. In this paper, the maximum torque per ampere control law is firstly transformed to a linear function, according to the first−order Taylor expansion, and integrated with the control strategy. On this basis, an improved predictive control method is formulated by designing an optimized cost function through the input−output feedback linearization. Then the integral action is introduced to eliminate the influence of the load mutation and improve the steady−state control precision of the system. The stability of the control method is ensured by compelling the outputs to track the desired references without steady−state error. Finally, the simulation was established to verify the effective of the improved control method. Simulation results showed that the machine can reach the given reference speed without steady−state error within a short process, which means the machine has excellent dynamic and static performances. Furthermore, the machine has higher torque−to−current ratio by making full use of the reluctance torque. The simulation results verify the effectiveness of the improved control strategy. Full article

This paper deals with the simulation of a permanent magnet synchronous machine (PMSM) to be developed for driving a scroll compressor of a vehicle air conditioning system. The simulations were needed for the verification of the pre-sizing and for the electromagnetic behavior analysis of the PMSM. These were performed by using the ANSYS Motor-CAD software. All the obtained results emphasized that the pre-sizing of the PMSM was performed correctly, and the designed electrical machine can fulfill all the prescribed requirements. To highlight the superiority of the chosen surface-mounted PMSM topology, a comparative study was performed for four PMSMs having the same stator but different rotor topologies having the same quantity of permanent magnets. The study revealed that the PMSM with permanent magnets on its rotor surface is the best-fitting variant for the foreseen application. By intensively using the ANSYS Motor-CAD software, the authors appreciated that this product is a very useful tool in the hands of the designers not only in evaluating the machine’s computed geometry (by checking its correctness and feasibility), but also in its in-depth electromagnetic analysis and in calculating its parameters of interest. Full article

Synchronous homopolar motors have no permanent magnets and their excitation winding is fixed at their stator. However, they can be a good alternative to induction and permanent magnet motors in traction applications requiring a wide constant power speed range. They provide an excitation flux control and a highly reliable brushless rotor design. This article presents the procedure and results of optimizing a 370 kW synchronous homopolar motor for driving subway train. The optimization procedure was developed to take into account the subway train moving trajectory. The analysis considers only a limited number of steady-state operating points of the motor to reduce computation time. The optimization results show a significant improvement of the target parameters of the traction drive. The optimization makes it possible to significantly reduce the losses in the operating cycle, as well as the torque ripple of the motor and the current rating of the traction inverter. Full article

Focusing on the unstable electromagnetic performance of an air gap magnetic field caused by torque ripple and harmonic interference of a multi-slot and multi-pole low-speed high-torque permanent magnet synchronous motor (LHPMSM), an asymmetric stator slot is proposed to improve the comprehensive electromagnetic performance of the motor. Moreover, this paper develops an exact analytical model which predicts the magnetic field distribution based on Laplace’s and Poisson’s equations. The stator slot asymmetry is introduced into the model and solved by the method of separating variables. Taking a 40p168s LHPMSM as an example, numerical results of the no-load flux density field distributions are obtained by the finite element method (FEM) and employed to validate the analytical model. The influence of stator slot asymmetric structure on electromagnetic characteristics is subsequently analyzed. The results show that, compared with the semi-closed slot model, the asymmetric slot has better torque characteristics, and the electromagnetic characteristics of the motor can be significantly improved by optimizing the stator slot asymmetry. Finally, a prototype is manufactured and tested to validate the theoretical analysis. Full article

In hydrogen recirculation side channel pumps, the motor rotor is exposed to a high-pressure mixture of steam and hydrogen, which makes hydrogen embrittlement occur in permanent magnets (PMs). A protective coating is necessary for the PMs in high-pressure hydrogen. However, in the process of sleeve interference installation, the protective coating of the PMs is easily damaged. This paper proposes two surface-mounted insert permanent magnet (SIPM) synchronous motor topologies, SIPM1 and SIPM2, in which the retaining sleeves can be eliminated and the PM protective coating is safe in the assembling process. A dovetail PM and rotor core structure is used to protect the PM with higher rotor strength without retaining the sleeve. The electromagnetic performance of the motors with different rotors, including airgap flux density, output torque, torque ripple, and energy efficiency is compared and optimized. It is concluded that the output torque of the SIPM motor can be promoted by 22.4% and torque ripple can be reduced by 2.9%, while the PM volume remains the same as that of the conventional SPM motor. At the same time, the SIPM motor can have lower harmonic contents of back electromotive force (EMF) and rotor loss compared to the SPM motor with a retaining sleeve. Furthermore, the stress of the PM is analyzed under conditions of PM glue action and failure. The proposed SIPM2 has the ability to operate safely at high-speed and high-temperature operating conditions when the PM glue fails. Full article

This paper presents an analytical model for calculating the detailed air-gap magnetic field distribution in interior permanent magnet synchronous motors (IPMSMs) with mixed eccentricity. In order to improve the efficiency of model solving, a modeling strategy combining the equivalent magnetic circuit network method and the subdomain method was adopted. Specifically, the magnetic field distribution of the rotor was modeled by using the magnetic circuit analysis method, and the magnetic field distributions of the air-gap, slot opening and stator slot along the radial direction were modeled in different regions according to their structure ruler. Then, the influence of bridge saturation was considered. Moreover, based on the analysis of the air-gap geometric structure with mixed eccentricity, a detailed spatiotemporal analytical model of the air-gap magnetic field was established, which provides a more accurate description of the mixed eccentricity composed of static and dynamic rotor eccentricities of different severity. The analytical models were compared with the corresponding models established by the finite element method, which proved the accuracy and validity of the models established in this paper. Finally, some key features related to radial and tangential air-gap flux density were extracted, which can significantly reflect the characteristics of eccentricities. The main findings reported in this paper will be of benefit for developing methods for early identification and diagnosis of eccentricity faults in IPMSMs. Full article

This paper describes the preliminary analysis, design and implementation phases of a DC/DC boost converter dedicated to the Futura catamaran propulsion chain developed by the UniBoAT team at the University of Bologna. The main goal of the project was the reduction of the converter’s weight by eliminating the use of heat sinks and by reducing the component size, especially inductors and capacitors. The obtained converter is directly integrated into the structure containing the fuel-cell stack. The realized converter was based on an interleaved architecture with six phases controlled through the average current mode control. The design was validated through simulations carried out using the LT-Spice software, whereas experimental validations were performed by means of both bench tests and on-field tests. Detailed thermal and efficiency analyses were provided with the bench tests under the two synchronous and non-synchronous operating modes and with the adoption of the phase-shedding technique. Prototype implementation and performance in real operating conditions are discussed in relation to on-field tests. The designed converter can be used in other applications requiring a voltage-controlled boost converter. Full article

The article presents the analysis of operational parameters and thermal analysis of the wheel hub motor during operation in the car drive. The authors proposed an analysis of the operation of the wheel hub motor mounted in a hybrid car, during Artemis driving cycles and while driving on the road with different slopes. The simulations were carried out in the Ansys Motor-CAD program. The calculations are based on coupled models of the electromagnetic circuit and thermal models of the motor. The conducted research is a proposal of an approach to the design of electric vehicle propulsion motors, which allows us to consider problems related to predicting at the motor design stage what are its possibilities and what risks during operation in a real drive. The analysis also includes the impact of the applied motor control strategy and the variation of the supply voltage. These are aspects that are extremely important in wheel hub motors, as they are weight-optimized motors with a limited volume and a relatively high power and torque density. Full article