Winding Interior Permanent Magnet Research Articles

A Tapped Winding Interior Permanent Magnet Synchronous Machine for Medium-Duty Delivery Trucks

A Tapped Winding Interior Permanent Magnet Synchronous Machine for Medium-Duty Delivery Trucks

Open-fault diagnosis and tolerant control of a dual inverter fed open-end winding interior permanent magnet synchronous motor

Open-fault diagnosis and tolerant control of a dual inverter fed open-end winding interior permanent magnet synchronous motor

D-Q Axis Inductance Analytical Calculation for Fractional-Slot Distributed Winding IPM Motor Based on Big-Small Pole Space Method

The d-q axis inductance is the crucial parameter for the interior permanent magnet (IPM) motor. In order to facilitate the design, analysis, and optimization of IPM motors, it is of great significance to develop an accurate and simplified inductance analytical calculation method. Among the existing calculation methods, the magnetic equivalent circuit (MEC) has advantages in the inductance calculation of the IPM motor due to the simple modeling, the fine processing of the saturation region and the visualization of the magnetic field distribution. However, the traditional MEC method is only applicable to the IPM motor with integer-slot distributed winding (ISDW) or fractional-slot concentrated winding (FSCW), while lacking of in-depth research on fractional-slot distributed winding (FSDW). The magnetic circuit topology of FSDW IPM motors is not as single as that of FSCW/ISDW IPM motors. It leads to problems in the traditional MEC method when dividing the d/q axis flux path in FSDW motors. To solve this problem and expand the applications of MEC method, a big-small pole space (BSPS) method is proposed after fully considering the common characteristics of MMF distribution and reluctance distribution in FSDW motors, which fills the gap of MEC method applied to FSDW motors. The BSPS method divides the d-axis flux path according to the asymmetry of the d-axis magnetomotive force (MMF). Based on the divided flux paths, an improved nonlinear MEC model that considers the saturation of stator and rotor is established to calculate d- and q-axis inductances. The results of finite element analysis (FEA) verify the validity of the proposed MEC model with different geometry parameters. Experimental results of an 84-pole/360-slot FSDW I-type IPM wind generator further confirm the validity of the proposed MEC model

Differential mode voltage reduction in dual inverters used to drive open-end winding interior permanent magnet synchronous motors

Differential mode voltage reduction in dual inverters used to drive open-end winding interior permanent magnet synchronous motors

Simple predictive torque control of an open‐end winding interior permanent magnet synchronous motor drive without weighting factor for electric vehicle applications

AbstractPermanent magnet synchronous motor (PMSM) drives are effectively used in the application of electric vehicles (EVs) due to their ease of construction and simpler in operation. Model predictive control (MPC) is an efficient control strategy used in motion control applications. Predictive torque control (PTC) is a type of MPC that selects a suitable voltage vector (VV) from a set of 19 VVs in order to minimize the cost function. However, as the control variables in the cost function in PTC are distinct, a weighting factor is essential. The tuning of the weighting factor is a burdensome control process. To address the limitations, the proposed PTC (P‐PTC) removes the weighting factor by using two cost functions, thus reducing flux ripples and torque ripples. Firstly, the P‐PTC evaluates the torque cost function for 19 VVs, and the VV that gives less value of torque error is used to find the sector number. The sector number is used to choose the five VVs from that sector and evaluate flux cost function to get an optimal VV. Therefore, the P‐PTC give less ripples in torque and flux by enhancing steady‐state response. The effectiveness of the P‐PTC is validated through both simulation and experimentation for a 3.7 kW OEW‐IPMSM drive using d‐SPACE RTI1104 controller. The P‐PTC is also tested with a typical urban dynamometer drive cycle (UDDC) with rapid accelerations and decelerations to ensure its application in EVs using the OPAL RT 1250 controller.

Design Optimization of Four-Layer Fraction Slot Concentrated Winding Spoke-Type Interior Permanent Magnetic Machine for Range Extender

<div>In this article, the design optimization of a four-layer fractional slot concentrated winding (FSCW) interior permanent magnet (IPM) machine for range extender is proposed for high energy efficiency and excellent torque/back-electromotive force (EMF) performance. The design starts with the comparison of four-layer FSCW patterns in terms of efficiency distribution based on a predesign spoke-type rotor model. Magnet segments and rotor auxiliary notches (ANs) are applied and optimized to reduce eddy current losses and torque ripples in the permanent magnets (PMs). Then, an efficient two-step optimization of multiple performances for a machine is presented. The rotor parameters are designed by an analytical model with a Pareto optimizer for torque capacity and ripple. An interpolation-based design method for adaptive stator slot parameters and winding configurations is presented to quickly obtain the optimal stator slot winding designs corresponding to the rotor design to achieve optimal efficiency. The multi-bridge design is applied to rotor laminations to suppress flux leakage, making the rotor core easy to manufacture. Finally, an 18s-16p four-layer FSCW prototype was built and tested to verify the design optimization results, with a maximum efficiency of 96% and rated shaft ripple as low as 3%.</div>

Inverter Power Device Fault Detection and Fail Safe Action Strategy for Electric Vehicle With a Dual Inverter Fed Open Winding Motor

A electric vehicle (EV) needs high drive system efficiency, low motor noise and limp-home capability of the traction drive when there is a component failure. A dual inverter fed open winding interior permanent magnet synchronous motor (DIF-OW-IPMSM) drive system satisfied all the above needs. In this paper, new algorithms for the inverter power device fault detection and fail-safe action strategy for the DIF-OW-IPMSM drive system in the entire speed region of the EV are proposed to prove its high reliability. The new algorithms for the inverter power device fault detection are derived from the sensed three phase fault currents and their subsequent analytical and logical processing within the micro-computer. The fail-safe action strategy is derived such that the unbalanced three phase fault currents using the dual inverters are quickly restored to balanced three phase currents using a single inverter and hence, the effect of the vibration of the traction motor due to undesired torque ripple during inverter device fault condition is kept minimum. The proposed new algorithms are verified by suitable simulation and experimental results, and the safe limp-home capability of the DIF-OW-IPMSM drive system is demonstrated.

Advanced DPWM Method for Switching Loss Reduction in Isolated DC Type Dual Inverter With Open-End Winding IPMSM

This paper proposes an advanced discontinuous pulse-width modulation (DPWM) scheme for a dual inverter to reduce switching loss. A dual inverter is used to drive an open-end winding interior permanent magnet synchronous motor (OEW-IPMSM). It is composed of double two-level inverters with large switching loss owing to the use of 12 switching devices. When a current phase changes, the switching loss cannot be minimized by using a conventional DPWM scheme. As the conventional DPWM scheme uses reference voltage for switching, the switching loss cannot be minimized due to the difference between the phases of the stator current and phases of reference voltages. However, the proposed DPWM scheme with additional calculations of the current phase can minimize switching loss. When the current phase changes, the proposed DPWM is switched to ±30° of the maximum point of the current. Furthermore, the effectiveness of the proposed switching loss reduction ability is verified through simulations and experimental results.

Numerical Investigations on Operation Modes and Transients of IPM Machines with Dual Windings

This paper investigates the flux-weakening characteristics and transient response of a dual winding interior permanent magnet (DWIPM) machine designed using the 2010 Toyota Prius IPM Machine specifications. In order to thoroughly adjust the main flux, dual windings are fed by separate identical inverters. Thus, significantly high-torque for high-speed requirements can be simply achieved by making one of the inverters open-circuited. Transient response of the DWIPM machine, including torque and current pulsations, occurring during normal drive or deactivation of one of the inverters has also been investigated for different operation modes. The flux-weakening performance characteristics of the proposed DWIPM machine have been compared with those of its single-fed counterpart in order to highlight the benefits and drawbacks of the dual-winding topology. The steady-state performance characteristics, torque/speed and power/speed curves, efficiency maps, machine transient response, different machine design options with various numbers of turns per phase and current amplitudes, and the importance of the electromagnetic coupling between dual windings have all been addressed. For transient and steady-state analyses, 2D, nonlinear, time-stepping finite element method (FEM) has been employed. It has been revealed that the proposed DWIPM machine exhibit significantly improved flux-weakening characteristics, particularly high-power at constant power region and high efficiency at constant torque region, and quite low current and torque pulsations occurring during operation mode change.

Control Method of Electrolytic Capacitorless Dual Inverter for Harmonic Compensation Under Distorted Grid Voltage

This article proposes a harmonic compensation method using an open-end winding interior permanent magnet synchronous motor driven by an electrolytic capacitorless dual inverter under grid disturbances. In a conventional electrolytic capacitorless single inverter, harmonic currents are superimposed on the output current of the inverter owing to the increase in the dc-link voltage ripple caused by grid disturbances. Consequently, the reliability of the motor drive system is reduced, and the torque ripple causes mechanical vibrations. The proposed harmonic compensation method estimates the harmonic voltage and outputs it using a compensating inverter. The experimental results show that peak-to-peak of the motor current and the 150 Hz component of the shaft torque are reduced by 10.3 and 92.4%, respectively, compared to the conventional system under unbalanced input voltage. Therefore, the improvement of reliability of a motor drive system and reduction of the torque ripple are achieved without an energy buffer under grid disturbances.

Design Consideration of Fractional Slot Concentrated Winding Interior Permanent Magnet Synchronous Motor for EV and HEV Applications

This paper presents a comprehensive study on the fractional slot concentrated winding (FSCW) interior permanent magnet synchronous motors (IPMSMs) with different pole slot combination for the application of electric vehicle (EV) and hybrid electric vehicle (HEV). Three motors with the same dimension constraint and rated parameters are designed and optimized. With the optimized motors, winding factors and magnetomotive force (MMF), inductances, torque capacity, constant power speed range (CPSR), the losses, the efficiency, demagnetization capability and vibration are investigated and compared. The comparison results show that 12/8 motor and 12/10 motor have their respective unique advantages while 12/14 motor is not as good as the others.

Maximum Torque Minimum Peak Phase Current of a Dual Winding Interior Permanent Magnet Synchronous Motor

Maximum Torque Minimum Peak Phase Current of a Dual Winding Interior Permanent Magnet Synchronous Motor

Vibration Optimization of FSCW-IPM Motor Based on Iron-Core Modification for Electric Vehicles

In this paper, to optimize vibration of the fractional slot concentrated winding interior permanent magnet (FSCW-IPM) motor for electric vehicles (EVs) without sacrificing any torque performance, modifications of iron-core structures are proposed. First, the effects of basic stator/rotor auxiliary slots on torque, cogging torque, torque ripple, and 2nd order spatial harmonic of radial force are investigated by finite element analysis (FEA). The combinations of stator/rotor auxiliary slots, which can optimize vibration with maintained torque, are analyzed. To improve torque and optimize vibration, uneven airgap rotor is proposed. With variation of the uneven air-gap rotor, torque improvement and vibration reduction do not contradict each other. The vibration levels of FSCW-IPM motors are calculated by magnetic-mechanical coupling models, while the peak vibrations are optimized with the proposed methods. Inductance, torque, and vibration experiments of the FSCW-IPM motor with the uneven airgap rotor are performed. The theoretical and experimental results both validate effectiveness of the proposed methods for torque improvement and vibration optimization.

Design and analysis of interior permanent magnet machines equipped with novel semi‐overlapping windings

A novel winding topology comprising semi-overlapped windings has been proposed in this study. The main advantages of such winding over conventional-distributed (overlapping) and fractional-concentrated (non-overlapping) windings are having very short-end winding lengths and significantly low magnetomotive force harmonic content, respectively. The key design rules, basic properties, and other merits and demerits of the proposed novel winding topology are justified. The key performance characteristics of the proposed winding topology are disclosed through an interior-permanent magnet (IPM) machine. The obtained electromagnetic analysis results are compared with those of other IPM machines having conventional-distributed and fractional-concentrated windings. It has been demonstrated that the proposed winding topology promises significant superiorities such as improved efficiency with substantially reduced total axial length, low eddy current losses, and low risk of irreversible magnet demagnetisation over other winding topologies. The analysis is verified by finite-element analysis results and experiments on a prototype novel semi-overlapping winding IPM machine.

Partially-Coupled d–q–0 Components of Magnetically-Isolated FSCW IPM Machines With Open-End-Winding Drives

Fractional-slot concentrated winding interior permanent magnet (FSCW-IPM) machines have been designed with very low winding mutual inductance for magnetic isolation features required for improving their fault-tolerant capabilities. These magnetically-isolated FSCW-IPM machines no longer adhere to the preconditions required for a conventional abc-to-dq0 transformation. As a result, it is found in this article that d-, q-axes could couple with 0-axis in magnetically-isolated FSCW-IPM machines. Considering the second-order reluctance component, this phenomenon leads to third-harmonic injection in phase voltages during normal operation, which can be cancelled out in terms of line-to-line voltage for Y-connected three-phase system. However, for open-end-winding machine drives without winding neutral point constraint, these voltage harmonics will show up in the winding voltage waveforms. Study shows that the amplitudes of these extra harmonics are determined by both saliency ratio and zero-axis current. The bandwidth of the proportional integral (PI) current regulator as well as switching frequency should be carefully determined to be able to take into account the major harmonics injected in phase voltages. Experimental verification on a 12-slot/10-pole prototype machine with spoke PMs has been carried out to show the impact of this phenomenon.

Analysis of Inter-Turn-Short Fault in an FSCW IPM Type Brushless Motor Considering Effect of Control Drive

A comprehensive analysis of inter-turn-short fault (ITSF) in a fractional slot concentrated winding (FSCW) interior permanent magnet synchronous motor (IPMSM) is presented in this article. During online fault detection, the fault signatures can be influenced by the controller action in a closed-loop control system. Therefore, this study focused on the comparison of the ITSF characteristics in an IPMSM using open-loop and closed-loop control drives. The variation rate in various parameters, such as flux density, input current, circulating current, torque ripple, and vibration under healthy and ITSF conditions are compared. Conventional six-step square-wave control (SSC) and field-oriented control (FOC) drives are respectively used for open-loop and closed-loop analysis of ITSF. Furthermore, this study also focuses on mitigating the capability of the control drives for achieving extended postfault life of the motor. Based on our analysis a fault mitigating strategy for the benchmark IPMSM is also suggested. A multidomain cosimulation technique is used to integrate the finite element method-based model of IPMSM with the control drives under different severities of ITSF for the simulation. Finally, experiments on a three-phase 400-W IPMSM are performed for verification. The result shows that in the FSCW machine the ITSF can be mitigated and FOC has a better capability of ITSF mitigation than SSC.

A Nonlinear $q$-Axis Inductance Modeling of a 12-Slot 10-Pole IPM Using Approximate Analytical Methods

This article introduces a novel nonlinear model for the $q$ -axis inductance of a Fractional Slot Concentrated Winding Interior Permanent Magnet (FSCW-IPM) machine in order to decrease the time needed to obtain a solution. The complicated geometry and nonlinear magnetic behavior of the core make analytical modeling difficult. So numerical methods are usually used to model machines in which magnetic saturation plays an important role. The winding function of a 12-slot 10-pole FSCW-IPM machine is analyzed and a magnetic equivalent circuit is obtained using the Lumped Parameter Method (LPM) according to the MMF distribution analysis. A mathematical function which represents the magnetic behavior of the core material is appropritely selected to reduce the equations, which show the relationship between the flux and MMF of every lumped parameter into the one equivalent equation. After that, perturbation theory and Pade approximants are used to solve the nonlinear equivalent equation. Finally, a new nonlinear analytical model and solution method is introduced for 12-slots 10-pole FSCW-IPM and the simulation time is decreased to under 0.5 s while it takes about 10 mins with FEA because the proposed method does not need any iteration. The proposed method is compared with FEA and experimental results and the comparison shows the proposed method has sufficient accuracy.

Torque Ripple Minimization for Inter-Turn Short-Circuit Fault Based on Open-Winding Five Phase FTFSCW-IPM Motor for Electric Vehicle Application

High reliability and fault-tolerant operation capability are the application requirements of electric vehicles(EVs). In case of the drive system suffering from inter-turn short-circuit (ITSC) fault, it is necessary to avoid the aggravation of the fault and ensure the normal output performance, this paper proposed a torque ripple minimization control strategy for ITSC fault based on the open-winding (OW) five phase fault tolerant fractional slot concentrated winding interior permanent magnet (FTFSCW-IPM) motor drive system with common DC bus. Once the ITSC fault is detected, the fault phase is active open-circuit (OC) (null the current of the normal part in the fault phase) and connected to a voltage sensor. In this way, the torque ripple minimization control strategy can deal with the OC fault and ITSC fault. For the OC fault, the equal amplitude phase current modulation strategy is adopted based on the carrier-based pulse width modulation (CPWM). For the ITSC fault, this paper proposed a feedforward compensation approach to eliminate the influence of the short-circuit loop current. The novelty of the proposed method is that the compensation can be real-time estimated using the zero-sequence voltage (ZSV) and zero-sequence current (ZSC), even the ITSC level changes. Simulation and experimental results demonstrate the effectiveness and feasibility of the proposed method.

A Design of Interior Permanent Magnet Synchronous Motor for Electric Vehicles

Fractional slot concentrated winding interior permanent magnet synchronous motor (PMSM) has the advantages of high torque density, high efficiency and simple manufacture, which has been widely used in electric vehicles. In this paper, a fractional slot concentrated winding interior permanent magnet synchronous motor (PMSM) with “▽” shape rotor is proposed. This paper focuses on how to reduce the torque ripple of the motor. The permanent magnet angle and eccentric length are optimized to maximize the fundamental air-gap flux density and minimize its torque ripple. The cogging torque, torque ripple, iron loss and efficiency of the motor are analyzed. Finally, the finite element results verify the effectiveness of the optimization.

Highly Demagnetization Performance IPMSM Under Hot Environments

This paper examines how changing the magnetic orientation of permanent magnets in concentrated winding interior permanent magnet synchronous motors (IPMSMs) affects their demagnetization resistance. We evaluated a prototype for demagnetization at 180 °C that consists of a 130° V-shaped rotor core in which parallelogram magnets with oblique orientation are arranged and confirmed by finite element analysis where the demagnetization resistance increases as magnetic field orientation angle $\alpha $ becomes larger. For demagnetization evaluation of the prototype, it is easier to change the rotor core shape of a two-pole test rotor of a multipole IPMSM than a multipole rotor, and the demagnetization evaluation is performed using a small number of magnets.