Interior Permanent Magnet Motor Research Articles

Effects of off-center of rotor on distributions of electromagnetic force

Some of the motors used for compressors of air-conditioners are cantilevered. The noise of the motor becomes louder when the rotor is off-centered. Therefore, it is important to analyze the motor with an off-centered rotor in order to reduce the noise from such motors, because it is not easy to measure the degree of the off-center in experiments. In this paper, an interior permanent-magnet motor with the off-centered rotor is analyzed using the three-dimensional finite-element method. Consequently, the effects of the off-center of rotor on the electromagnetic distributions and those harmonic components are quantitatively clarified.

Novel Rotor Position Extraction Based on Carrier Frequency Component Method (CFCM) Using Two Reference Frames for IPM Drives

In this paper a novel interior permanent-magnet (IPM) motor's rotor position extraction method from the carrier-frequency component signal, derived from pulsewidth-modulated (PWM) inverter switching, using two reference frames is presented. This method has been utilized for IPM motor vector control without a mechanical rotor position detector, extracting rotor position angle from the switching carrier-frequency (10 kHz) component current. It is effective for IPM motors, which have magnetic saliency, sinusoidal distributed stator winding, and are supplied by a PWM voltage-source inverter. The performance of two IPM motors' vector control without mechanical rotor position detector utilizing this method has been investigated. Experimental results demonstrating good dynamic and steady-state performance achieved are presented and discussed.

Feedback-Linearizing Control of IPM Motors Considering Magnetic Saturation Effect

This paper describes feedback-linearizing control of interior permanent magnet (IPM) motors which operate in magnetic saturation. First, we propose a current tracking controller for direct control of stator currents. Then, we explicitly characterize all torque controllers that can make the motor torque of an IPM motor exactly linear with respect to torque command even if magnetic saturation occurs. In particular, our torque controller contains a free function that can be used to achieve other control objectives as well as linear dynamic characteristics. Finally, the free function is chosen so optimal as to maximize power efficiency. The practical use of our control method is demonstrated through various simulation and experimental results.

Simulation and Analysis of Magnetisation Characteristics of Interior Permanent Magnet Motors

Modern permanent magnet (PM) synchronous brushless machines often have magnetic circuits in which the patterns of saturation are complex and highly variable with the position of the rotor. The classical phasor diagram theory of operation relies on the assumption of sinusoidal variation of flux-linkage with rotor position, and neglects the non-linear effects that arise in different operating states. The finite element method is a useful tool for detailed magnetic analysis, but it is important to verify simulation results by direct measurement of the magnetic characteristics of the motor, in terms of “magnetisation curves” of current and flux-linkage. This paper presents results from finite element simulations to determine the magnetisation in a split-phase interior permanent magnet (IPM) motor. Investigation has been made to determine the effects of the rotor geometry on the synchronous reactances and airgap flux distribution. Comparisons are made with a second IPM motor with a different rotor configuration.

Real-Time Performance Evaluation of a Genetic-Algorithm-Based Fuzzy Logic Controller for IPM Motor Drives

This work presents a novel speed control scheme using a genetic-based fuzzy logic controller (GFLC) for an interior permanent-magnet synchronous motor (IPMSM) drive. The proposed GFLC is developed to have less computational burden, which makes it suitable for real-time implementation. The parameters for the GFLC are tuned by genetic algorithm (GA). The complete drive incorporating the GFLC is successfully implemented in real-time using a digital signal processor board DS 1102 for a laboratory 1-hp interior permanent magnet motor. The efficacy of the proposed GFLC-based IPMSM drive is verified by simulation as well as experimental results at various operating conditions. A performance comparison with a conventional proportional-integral controller is also provided to show the superiority of the proposed controller. The proposed GFLC is found to be robust for high-performance industrial drive applications.

Fault detection and fault-tolerant control of interior permanent-magnet motor drive system for electric vehicle

This work presents a control strategy that provides fault tolerance to the major sensor faults which may occur in an interior-permanent-magnet-motor (IPMM)-based electric vehicle propulsion drive system. Failures of a position sensor, a dc-link voltage sensor, and current sensors are all included in the study assuming no multiple faults. For each possible sensor fault, a corresponding method of detection or diagnosis is provided. Additionally, once the fault is detected, the control scheme is automatically reconfigured to provide post-fault operational capability. A state observer is used to provide missing current information in the case of current sensor faults. Experimental results demonstrate the effectiveness of both the fault detection algorithm and the reconfigurable control scheme. The resulting IPMM drive system proves to be resilient to sensor failures while providing smooth transition to the post-fault operational mode.

キャリア高調波を考慮したIPMモータの鉄損解析

In this paper, we investigate the iron loss of interior permanent magnet motors driven by PWM inverters using electromagnetic field analysis. Following 4 methods are applied: (1) Current input finite element method neglecting the carrier harmonics. (2) Voltage input finite element analysis neglecting carrier harmonics. (3) Current input finite element method with the measured armature current waveforms including the carrier harmonics. (4) Voltage input finite element method with the theoretical voltage waveforms of the PWM inverter. The calculated results are compared with the experimental ones. It is clarified that the accuracy of the calculated results are improved by considering the carrier harmonics and that the method (4) can estimate the iron loss of the IPM motor accurately before manufacturing. The variation of the iron loss components due to the driving condition is also clarified.

アキシャル構造によるHEV用IPMモータの薄型化

An interior permanent magnet synchronous motor (IPMSM) operates by two kinds of torque mechanism, just as the magnet torque and the reluctance torque, and has compact size and high efficiency. Recently, you can see increasing demand for the low-profile interior permanent magnet motor set in the hybrid electric vehicle (HEV). An axial-flux type interior permanent magnet synchronous motor (AIPMSM) is proposed as one of low-profile interior permanent magnet motors. This paper reports inspection of optimal structure for thining by use of finite element method.

Optimal Efficiency Control Strategy for Interior Permanent-Magnet Synchronous Motor Drives

In this paper, the problem of efficiency optimization in vector-controlled interior permanent-magnet (PM) synchronous motor drives is investigated. A loss model controller is introduced that determines the optimal d-axis component of the stator current that minimizes power losses. For the implementation of the suggested controller, the knowledge of the loss model is not required since an experimental procedure is followed to determine its parameters. Furthermore, it is shown that the loss model of the interior PM motor can be used as a basis for deriving loss minimization conditions for surface PM synchronous motors and synchronous reluctance motors as well. Experimental results of an interior PM motor are presented to validate the effectiveness of the proposed method and demonstrate the operational improvements.

Characterization of Noise and Vibration Sources in Interior Permanent-Magnet Brushless DC Motors

This work characterizes electromagnetic excitation forces in interior permanent-magnet (IPM) brushless direct current (BLDC) motors and investigates their effects on noise and vibration. First, the electromagnetic excitations are classified into three sources: 1) so-called cogging torque, for which we propose an efficient technique of computation that takes into account saturation effects as a function of rotor position; 2) ripples of mutual and reluctance torque, for which we develop an equation to characterize the combination of space harmonics of inductances and flux linkages related to permanent magnets and time harmonics of current; and 3) fluctuation of attractive forces in the radial direction between the stator and rotor, for which we analyze contributions of electric currents as well as permanent magnets by the finite-element method. Then, the paper reports on an experimental investigation of influences of structural dynamic characteristics such as natural frequencies and mode shapes, as well as electromagnetic excitation forces, on noise and vibration in an IPM motor used in washing machines.

Characteristics of Permanent-Magnet Synchronous Motor Driven by PWM Inverter With Voltage Booster

The steady-state characteristics of an interior permanent-magnet (IPM) motor driven by a pulse-width-modulation (PWM) inverter with voltage booster are analyzed and the transient behavior is investigated. The PWM inverter with voltage booster consists of a conventional PWM inverter and a voltage booster to control the DC-link voltage. The current trajectory on the i/sub d/-i/sub q/ plane is illustrated and the torque, voltage, and current versus speed characteristics are represented. Furthermore, the analytical and simulated results are compared to the experimental results for a 1.5 kW IPM motor and the validity of the analysis and simulation is confirmed by their agreement.

High-Efficiency Line-Start Interior Permanent-Magnet Synchronous Motors

This paper presents a successful design of a high-efficiency small but novel interior permanent-magnet motor using NdBFe magnets. It is designed to operate both at line and variable frequencies. Line start with high inertia load was a special consideration. Time-stepping finite-element analysis has been used to successfully predict the dynamic and transient performances of the prototype motors. It has been found that the proposed design has yielded successful simulation and experimental results. The maximum load inertia corresponding to the rotor-bar depth has been determined from the simulation results.

Induced voltage analysis of interior permanent magnet motor taking into account Y- or Δ-connected circuit using 3-D finite element method

In this paper, we introduce the three-dimensional finite element method (3-D FEM) taking into account the ∆- connected circuit for obtaining the induced voltages of the three-phase motor. We calculate the induced voltage of interior permanent magnet (IPM) motor taking into account the Y- or the ∆-connected circuit of motors using the proposed method. The effects of the connection on the induced voltage are numerically analyzed. The validity of our method is clarified by comparing the calculated results and measured ones.

Bridge design of interior permanent magnet motor for hybrid electric vehicle

Bridge design of interior permanent magnet motor for hybrid electric vehicle

電解コンデンサレス高力率単相ダイオード整流回路を持つインバータによるＩＰＭモータの一駆動法

This paper proposes a new inverter drive system for an interior permanent magnet (IPM) synchronous motor and an inverter control strategy to obtain the unity power factor operation of the single-phase diode rectifier. The motor drive system for home appliances requires improving the input power factor without a reactor, an electrolytic capacitor and a switching device. This paper can achieve to improve the input power factor without a reactor, a current control-switching converter and an electrolytic capacitor. The proposed system consists of only single-phase diode rectifier, small film capacitor (10uF/kW) across the dc-bus, three-phase inverter and IPM motor. Source side energy provides directly to the motor without smoothing the dc-bus voltage. There are many ripple voltages across the dc-bus. A principle of unity-power-factor operation is that the inverter makes the waveform of input current sinusoidal. The unity power factor operation is achieved by dither effect. For IPM motor, the inverter control scheme in this paper is based on direct torque control (DTC). The proposed system is constructed by the input current controller based on DTC. The additional current controller improves its input current waveform. This paper describes that the proposed method achieves the power factor 98.8% by experimental tests.

Dynamic analysis of interior permanent magnet motor based on a magnetic circuit model

This paper presents a new magnetic circuit model of an interior permanent magnet (IPM) motor for use in SPICE, which is the general-purpose circuit-simulation program. The magnetic circuit model consists of reluctances and permanent magnet magnetomotive-force sources. In the SPICE simulation, a magnetic circuit model of the IPM motor and its driving circuit are coupled by a proper circuit. Using the proposed model, we can calculate dynamic characteristics of the IPM motor easily.

Walsh function‐based position sensorless control for interior permanent magnet motor drives using ripple‐current of high‐frequency triangular‐wave‐carrier PWM inverter

AbstractThis paper proposes the Walsh function‐based position sensorless drive method of a PM motor by using high‐frequency 20‐kHz triangular‐wave‐carrier PWM inverter ripple current. The proposed method uses the Walsh harmonic of PWM inverter ripple current to estimate the motor rotor position. By using the high‐frequency switching ripple current, the period of the rotor position estimation has been decreased and improves the step response of PM motor. The Walsh function makes it possible to use a definite integrator as the Walsh harmonic detector that can separate the small ripple‐current signal from the motor drive‐current signal. The Walsh harmonic detector circuit consists of less parts than the Fourier harmonic detector circuit. The validity of the proposed method was clarified by several experimental results. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(3): 80–88, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10205

The influence of topology selection on the design of EV/HEV propulsion systems

The adoption of the 42 V Powernet standard has focused substantial research effort into the design of electric machines for hybrid vehicles. This letter investigates the potential performance benefits afforded by adopting a cascaded inverter topology on the overall system and motor performance. As a particular design example, this letter shows that a cascaded inverter driving an open winding motor can increase the high-speed power density of an induction motor by 73%. For an interior permanent magnet motor, the cascaded topology can increase low-speed torque by 9% and high-speed power by up to 300%. In all cases, the power increase is achieved without increasing the phase current over a more traditional system.

Effect of maximum torque according to the permanent magnet configuration of a brushless dc motor with concentrated winding

A brushless dc (BLDC) motor, which has a permanent magnet (PM) component, is a potential candidate for hybrid or electric vehicle applications. Minimizing the BLDC motor size is an important requirement for application. This requirement is usually satisfied by adopting a high performance permanent magnet or improved winding methods. The PM configuration is also a critical point in design. This article presents the effect of the PM configuration on motor performance, especially the maximum torque. Four representative BLDC motor types are analytically investigated under the condition that the volume of the PM and magnetic material is constant. An embedded interior permanent magnet motor has the best torque performance the maximum torque of which is more than 1.5 times larger than that of the surface mounted permanent magnet motor. The performance of back electromotive force, instantaneous torques is also investigated.

Sensorless rotor position estimation of an interior permanent-magnet motor from initial states

This paper describes a torque, speed, or position control method at standstill and low speed in the interior permanent-magnet motor (IPMM) drive system without any rotational transducer. While IPMMs have originally magnetic saliency, it varies according to the load conditions and the control performance can be easily degraded. In this paper, the saliency or impedance difference is used as the conventional methods and, nevertheless, in order to amplify the difference containing the information of the rotor angle and to maintain a reasonable performance under any load condition a high-frequency injection scheme is proposed. A speed and position estimation scheme based on the characteristics of the high-frequency impedance is proposed. The scheme extracts the high-frequency impedance components related to the rotor position. An initial angle estimation scheme for starting from an arbitrary rotor position is also proposed. It can distinguish the north magnetic pole position from the south one in several decade milliseconds. The proposed scheme enables position control of a transducerless or position-sensorless IPMM. The experimental results clarify the satisfactory operation of the proposed position control algorithm under any load condition.