Winding Permanent Magnet Synchronous Motor Research Articles

Asymmetric dual winding three‐phase PMSM for fault tolerance of overheat in electric braking system of autonomous vehicle

In this paper, an asymmetric dual winding three-phase permanent magnet synchronous motor (PMSM) is proposed for enhancing the fault-tolerance of overheat in autonomous vehicles. A conventional dual winding three-phase motor is divided into two three-phase windings, one for the master part and one for the slave part. It is advantageous to have a redundant system by combining two electric control units (ECU) with one motor instead of two motors. However, when the motor is burned out due to excessive overload driving beyond the motor design value, there is a possibility that no operation can be performed even though there are two ECUs. The proposed dual winding three-phase asymmetric motors are designed differently in the master and slave windings so that the simultaneous burnout of master and slave can be avoided. The coil temperature rise according to the asymmetrical winding design of the motor is estimated by the thermal equivalent circuit method. Also, optimal design for proposed model is conducted using the radial basis function (RBF) and the experimental design method. The optimized proposed asymmetric dual winding three-phase PMSM is applied to the design of motor for electric brake systems of an autonomous vehicle and is verified its usefulness.

Direct Torque Control for Three-Phase Open-End Winding PMSM With Common DC Bus Based on Duty Ratio Modulation

This article introduces the classical direct torque control (DTC) to a three-phase open-end winding permanent magnet synchronous motor with common dc bus for the first time. The electromagnetic torque and the stator flux are controlled at the same time. However, the zero-sequence current is not suppressed, and the ripples of the electromagnetic torque and stator flux are large. To improve the operation performance of this drive system, a DTC based on a duty ratio modulation (DRM-DTC) is proposed. First, a deadbeat zero-sequence current controller is proposed in the DRM-DTC to suppress the zero-sequence current. Second, another strategy, which is based on a graphical analysis method and a simple deadbeat direct torque and flux controller, is proposed to optimize the duty ratio of the active voltage vector. Thus, the electromagnetic torque and stator flux ripples can be reduced. Finally, an optimized pulsewidth modulation implementation strategy is proposed in the DRM-DTC to further reduce the switching frequency of inverters. The classical DTC and the proposed DRM-DTC are compared through simulation and experiment, and the results verify the effectiveness of the proposed strategy.

SVPWM Strategy Based on the Hysteresis Controller of Zero-Sequence Current for Three-Phase Open-End Winding PMSM

Owing to high driving power, good controllability, and strong fault-tolerant ability, a three-phase open-end winding permanent magnet synchronous motor driven by a dual inverter with common dc bus is considered as a competitive solution. However, a path for zero-sequence current is provided in this drive topology. Thus, the system loss would be increased, and the maximum output power is limited. In order to suppress the zero-sequence current, a novel space vector pulsewidth modulation (SVPWM) strategy based on the hysteresis controller of zero-sequence current is proposed in this paper. The voltage vectors, whose polarity of zero-sequence voltages (ZSVs) is opposite with the polarity of zero-sequence current, are selected as the basic voltage vectors of SVPWM for fundamental plane. Meanwhile, the linear modulation range is analyzed. According to the analysis results, the proposed strategy has the advantage of wide linear modulation range of ZSV under the condition of high fundamental modulation ratio. The experimental results show that the zero-sequence current is effectively suppressed by the proposed modulation strategy. Furthermore, the comparative evaluation of the proposed modulation strategy, the conventional SVPWM, the SVPWM with zero ZSVs, and the zero vector redistribution SVPWM with zero-sequence current proportional-resonant controller is conducted to demonstrate the superiority of the proposed strategy.

Position sensorless direct torque control for six‐phase permanent magnet synchronous motor under two‐phase open circuit

A position sensor is usually required in the existing fault-tolerant direct torque control (FT-DTC) system for the multiphase permanent magnet synchronous motor (PMSM). Thus, the volume, weight, and cost of the system is increased, and the reliability is decreased. The conventional high-performance position sensorless strategies for the multiphase motor under fault-free condition cannot be directly applied to FT-DTC system. To improve this situation, a high-speed position sensorless FT-DTC strategy for a six-phase symmetrical winding PMSM with two opened phases is proposed in this study. Firstly, modified variables and a new rotating coordinate system are defined to achieve the symmetrical and decoupled mathematical model. Secondly, a stator flux observer based on the modified variables and a new coordinate system is proposed. According to the current model of modified stator flux, the estimated modified stator current can be achieved. Then, the estimated error of the modified stator current is sent to the integrator of the modified stator flux observer to correct the voltage model. Finally, the proposed stator flux observer is applied in FT-DTC for six-phase PMSM with two opened phases to realize the position sensorless operation at high speed. The experimental results verify the feasibility and effectiveness of the proposed strategy.

On-Line Stator Resistance and Permanent Magnet Flux Linkage Identification on Open-End Winding PMSM Drives

This paper deals with the development and implementation of an on-line technique for the identification of the stator resistance and permanent magnet flux linkage on three-phase, open-end winding, permanent magnet synchronous motor (PMSM) drives. The stator resistance and permanent magnet flux linkage are independently determined by exploiting a special current vector control strategy, which holds one of the phase currents at zero while suitably modifying the other two in order to keep the magnetomotive force unchanged. As will be demonstrated, no additional sensors or special tests are required by the proposed technique; moreover, motor electrical parameters can be on-line estimated in a wide operating range, avoiding any detrimental impact on the torque capability of the PMSM drive. Finally, the electrical machine thermal status can be also estimated from obtained values of the stator resistance and permanent magnet flux linkage.

Analysis of Vibration and Noise in Permanent Magnet Synchronous Motors With Distributed Winding for the PWM Method

This paper describes the spatial mode, frequencies, the voltage reference update timing, and their interaction of pulsewidth modulation (PWM) harmonics, focusing on a distributed winding permanent magnet synchronous motor. We investigated the electromagnetic force generating the noise by using a couple of analyses between a circuit simulator and a two-dimensional finite element analysis. It was found that the electromagnetic noise and vibration result from a radial electromagnetic force spaced at the spatial zeroth mode of $f_{c}\pm 3f_{1},f_{c}$ , and ${{2}}f_{c}$ ( $f_{c}$ : carrier frequency, $f_{1}$ : fundamental frequency of the current). We have shown that the radial electromagnetic force of frequency $f_{c}\pm 3f_{1}$ and ${{2}}f_{c}$ results from PWM harmonics. Also, the radial electromagnetic force of frequency $f_{c}$ evidently results from the voltage reference update timing of ${{1/ }}f_{c}$ . The electromagnetic noise and the spatial mode are demonstrated in the experiment.

Vibration Reduction by Applying Carrier Phase-Shift PWM on Dual Three-Phase Winding Permanent Magnet Synchronous Motor

This paper investigates a method of reducing the vibration property of a permanent magnet synchronous motor (PMSM) with dual three-phase windings, especially focusing on carrier harmonics. Electromagnetic excitation force on carrier harmonics, which makes carrier harmonic vibration, is formulated and the relationship of the carrier phase difference between the space and the time phase difference to cancel out the excitation force is calculated for dual three-phase winding PMSM. Then, the carrier phase-shift space vector pulsewidth modulation (SVPWM), which makes any difference between the PWM carrier phase of the first and second windings, is applied to a 24-slot 20-pole PMSM. A test motor is manufactured and measured results reveal that the vibration and sound pressure can be approximately halved at around carrier harmonic and twice carrier harmonic when the carrier phase is π/2 radian compared to conventional in-phase carrier PWM.

Double Independent Three-Phase Winding Permanent-Magnet Synchronous Motors with Iron Loss

Double Independent Three-Phase Winding Permanent-Magnet Synchronous Motors with Iron Loss

Power Sharing and Voltage Vector Distribution Model of a Dual Inverter Open-End Winding Motor Drive System for Electric Vehicles

A drive system with an open-end winding permanent magnet synchronous motor (OW-PMSM) fed by a dual inverter and powered by two independent power sources is suitable for electric vehicles. By using an energy conversion device as primary power source and an energy storage element as secondary power source, this configuration can not only lower the DC-bus voltage and extend the driving range, but also handle the power sharing between two power sources without a DC/DC (direct current to direct current) converter. Based on a drive system model with voltage vector distribution, this paper proposes a desired power sharing calculation method and three different voltage vector distribution methods. By their selection strategy the optimal voltage vector distribution method can be selected according to the operating conditions. On the basis of the integral synthesizing of the desired voltage vector, the proposed voltage vector distribution method can reduce the inverter switching frequency while making the primary power source follow its desired output power. Simulation results confirm the validity of the proposed methods, which improve the primary power source’s energy efficiency by regulating its output power and lessen inverter switching loss by reducing the switching frequency. This system also provides an approach to the energy management function of electric vehicles.

Power Flow Control Strategy Based on the Voltage Vector Distribution for a Dual Power Electric Vehicle With an Open-End Winding Motor Drive System

A dual inverter feeding an open-end winding permanent magnet synchronous motor drive system can realize controllable power sharing or power flow between two independent power sources without a dc/dc converter. The two power sources can be selected among many options, such as fuel cells, engine generators, batteries, and supercapacitors. In this paper, the dual inverter’s voltage vector distribution and power flow principles are discussed. Based on the analyses of the overlapping area of the two inverters’ modulation ranges, the dual inverter’s modulation capability is exploited sufficiently. A novel voltage vector distribution strategy is proposed based on a dual space vector pulse-width modulation control scheme, which is composed of four patterns using basic voltage vectors, single-saturated vectors, double-saturated vectors, and linear-saturated vectors, respectively. By selecting the most suitable pattern, the power-sharing demand can be met in its maximum range while the switching frequencies of the two inverters are lowered and well-balanced. Simulation results confirm the validity and the advantages of the proposed strategy and clarify the power-sharing range in the entire operating range of the motor. This system also provides a scheme for energy management in electric vehicle applications.

Research on Control Strategies of an Open-End Winding Permanent Magnet Synchronous Driving Motor (OW-PMSM)-Equipped Dual Inverter with a Switchable Winding Mode for Electric Vehicles

An open-end winding permanent magnet synchronous motor (PMSM) has a larger range of speed regulation than normal PMSM with the same DC voltage, and the control method is more flexible. It can also manage energy distribution between two power sources without a DC/DC converter. This paper aims at an electric vehicle equipped with OW-PMSM drive system with dual power sources and dual inverters; based on analyzing the external characteristics of each winding mode, we propose a winding mode switching strategy whose torque saturation judgmental algorithm, which is insensitive to motor’s parameters, could automatically realize upswitching of the winding mode. The proposed multi-level current hysteresis modulation algorithm could set the major power source and switch it at any time in independent mode, which accomplishes energy distribution between two power sources; its two control methods, low switching frequency method and high power difference method, could achieve different energy distribution effects. Simulation results confirm the validity and effectiveness of the winding mode switching strategy and current modulation method. They also show that an electric vehicle under the proposed control methods has better efficiency than one equipped with a traditional OW-PMSM drive system under traditional control.

PWM Carrier Harmonic Iron Loss Reduction Technique of Permanent-Magnet Motors for Electric Vehicles

This paper investigates a method to increase fuel economy of motors for an electric vehicle (EV) traction system. The low-torque region of an EV motor is frequently used in everyday urban driving and in fuel economy measurement. Pulsewidth modulation (PWM) carrier harmonic iron loss accounts for a high percentage of total loss for EV motors in this region. This paper reveals the relationship between phase current and carrier harmonic iron loss for a permanent-magnet synchronous motor (PMSM) in the low-torque region. Thus, a novel carrier harmonic loss reduction technique is proposed and applied to two sets of three-phase windings for a concentrated winding PMSM. The loss is successfully reduced in a 70-kW EV motor as well as a two-dimensional finite-element method (2-D-FEM) calculation. The efficiency of the developed motor is calculated and compared with that of a conventional motor in the JC08 mode driving cycle.

Dual-Space Vector Control of Open-End Winding Permanent Magnet Synchronous Motor Drive Fed by Dual Inverter

This paper proposes a dual-space vector control scheme for the open-end winding permanent magnet synchronous motor (OEW-PMSM) drive fed by the dual inverter with a single dc supply. Potential zero-sequence current in the open-end winding drive system has to be considered since it causes circulating current in the winding and leads to high current stress of power semiconductor devices and high losses. Zero-sequence current in open-end winding ac motor drives is usually caused by the zero-sequence voltage, and therefore switching combinations which do not produce zero-sequence voltage are used to synthesize the reference voltage in existing methods. But even so, the zero-sequence voltage can also be produced by the dead time of the inverter. In order to suppress zero-sequence current in the OEW-PMSM drive, a dual-space vector control scheme is proposed and a novel dual-inverter space vector pulse width modulation (PWM) with the zero-sequence voltage reference is employed to regulate system zero-sequence voltage in this paper. Compared with existing dual inverter PWM strategies, the novel algorithm build a regulation mechanism for the zero-sequence voltage. The proposed method is compared with the conventional vector control by simulations and experiments, and the results shown that the proposed scheme can suppress zero-sequence current effectively.

Basic Study on Loss Factor Evaluation of Concentrated Winding Permanent Magnet Synchronous Motor

SUMMARYThis paper describes the influence of pulse width modulation (PWM) inverter harmonic loss on concentrated winding interior permanent magnet synchronous motor characteristics by using finite element method (FEM) analysis and several measurements. In the measurements, the PWM inverter harmonic loss was evaluated by using a PWM inverter and a sinusoidal power supply. By using the FEM analysis, it was confirmed that the PWM inverter harmonic mainly caused an increase of eddy current losses in the magnetic steel sheet and the permanent magnet. The results indicate that higher inductance of the motor is effective in reducing the harmful effects of PWM inverter harmonics.

Harmonic Winding Factors and MMF Analysis for Five-phase Fractional-slot Concentrated Winding PMSM

To enhance torque density by harmonic current injection, optimal slot/pole combinations for five-phase permanent magnet synchronous motors (PMSM) with fractional-slot concentrated windings (FSCW) are chosen. The synchronous and the third harmonic winding factors are calculated for a series of slot/pole combinations. Two five-phase PMSM, with general FSCW (GFSCW) and modular stator FSCW (MFSCW), are analyzed and compared in detail, including the stator structures, star of slots diagrams, and MMF harmonic analysis based on the winding function theory. The analytical results are verified by finite element method, the torque characteristics and phase back-EMF are also taken into considerations. Results show that the MFSCW PMSM can produce higher average torque, while characterized by more MMF harmonic contents and larger ripple torque.

Reduction of Vibration in Concentrated Winding Permanent Magnet Synchronous Motor by Means of Skew Effects of Rotor

SUMMARYGlobal warming and the problem of successfully incorporating environmental safeguards are promoting the need for a more power‐efficient motor. Therefore, as a driving source, permanent magnet synchronous motors (PMSMs) with concentrated winding are widely used in a variety of fields. However, a PMSM with a concentrated winding generates more vibration than one with a distributed winding because of the radial electromagnetic force. This paper describes the effect of a new skewed rotor on the characteristics of a concentrated winding PMSM. We investigated this effect by three‐dimensional finite element method (3D FEM) analysis and measurement. We also demonstrate that the proposed rotor is effective in reducing the radial electromagnetic force without decreasing motor efficiency. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(2): 33–43, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22400

Basic Study on Loss Factor Evaluation of Concentrated Winding Permanent Magnet Synchronous Motor

SUMMARY This paper describes the influence of pulse width modulation (PWM) inverter harmonic loss on concentrated winding interior permanent magnet synchronous motor characteristics by using finite element method (FEM) analysis and several measurements. In the measurements, the PWM inverter harmonic loss was evaluated by using a PWM inverter and a sinusoidal power supply. By using the FEM analysis, it was confirmed that the PWM inverter harmonic mainly caused an increase of eddy current losses in the magnetic steel sheet and the permanent magnet. The results indicate that higher inductance of the motor is effective in reducing the harmful effects of PWM inverter harmonics.

A Mixed Function for Actuation and Power Flow Control in Embedded Networks

This paper proposes an original association of a three-phase electrical machine, here a permanent-magnet synchronous motor (PMSM) fed by two inverters, which allows to combine two different functions: actuation and power transfers between two DC buses which supply the inverters. The considered AC machine is an open-end winding PMSM allowing the connection of two inverters supplied by two different DC buses inside a high-voltage DC network. The control part of this system uses the Park's theory not only to drive the actuator in motor as well as in generator operating modes but also to control the energy transfer from one DC bus to the other. The concept, mixing two main functions, is named MAPFC, for “mixed actuation and power flow control.” It has been particularly developed for aeronautic applications even if other application fields could be targeted. The complete modeling and operation of the system are described. Simulation studies and experimental results are presented, which are validating the proposed concepts.

Study on Reduction in Vibrations of Concentrated Winding Permanent Magnet Synchronous Motor by Skew Effects of Rotor

Study on Reduction in Vibrations of Concentrated Winding Permanent Magnet Synchronous Motor by Skew Effects of Rotor

Reduction of Vibration on Concentrated Winding Permanent Magnet Synchronous Motors with Considering Radial Stress

Concentrated winding motors have a tendency to increase its vibration, and the vibration is bigger than distributed winding motors. This phenomenon is caused by tugging force between two neighboring teeth. Accordingly, we tried to reduce the vibration with considering radial stress of the motor. In this paper, it is shown that radial stress becomes partly big, and it makes excitation of stator core in natural mode of radial vibration. Therefore, air gap length where radial force is big should be enlarged. Furthermore, we found that radial stress in air gap becomes smoothly by enlarging air gap partly, and we can reduce the vibration the motors without decreasing its efficiency.