Constant Power Operation Range Research Articles

회전속도와 간극 폭에 따른 모터의 열전달 특성에 대한 수치적 연구

Three-dimensional computations are performed to investigate the flow and thermal characteristics of a synchronous reluctance motor, which is capable of wide range of constant power and variable speed operation required for industrial applications such as control devices. This work focuses on the effects of rotational speed and rotor-stator gap width on the flow and thermal characteristics. The present computations show that thermal generation and convection changes with rotational speed have a significant effect on the motor temperature distribution, and that the flow and temperature fields in the rotor-stator gap strongly depends on the rotational speed and gap width relative the critical conditions. The heat transfer path in the motor is comparatively analyzed according to the rotational speed and rotor-stator gap.

High efficiency single‐pulse controlled switched reluctance motor drive based on novel multilevel converter

Due to the high back electromotive force and short commutation time at high speed, the phase current of switched reluctance motor (SRM) is difficult to reach a large value, which limits the output performance of the motor in high-speed operation. This paper proposes a novel multilevel converter (MLC) with fast excitation and fast demagnetisation capability, which allows each phase to control independently even in overlapping conduction operation and is suitable for SRM with any number of phases. The excitation current in the rising inductance region is increased by high-voltage fast excitation, thus increasing the phase current level of the motor at high speed; the current tailing in the falling inductance region is suppressed by high-voltage fast demagnetisation, thereby reducing the generation of negative torque. Based on the novel MLC, a maximum torque per ampere (MTPA) control strategy is designed, and closed-loop control of the boost capacitor voltage is developed. By optimising control, the output torque and efficiency of switched reluctance motor drive (SRD) are greatly improved, and the constant power operation range is extended. Simulation study and experimental results verify the effectiveness of the proposed scheme.

A Novel DC-Biased Current Dual PM Vernier Machine

In this article, a novel electric machine having permanent magnets (PMs) in both stator and rotor parts, and fed with dc biased phase current is proposed. The innovative characteristic of the proposed machine is that it contains multiple field excitation sources including stator PM, rotor PM. and dc component in the phase current. Thus, the exciting field can be greatly strengthened. What is more, the exciting field is flexible and adjustable thanks to the variable dc component. Therefore, the proposed machine is expected to exhibit high torque density, wide constant power operation range. This article first illustrates the basic operation principle, slot/pole combination equation, and the topology. Then, performance of six machines with different slot/pole combination is analyzed. After that, effects of several key design parameters on machine performance are researched theoretically and by finite-element method and genetic algorithm. And neural network is applied to verify the correctness of torque and torque ripple. Finally, the electromagnetic performance including flux density, back electromotive force, torque quality of an optimized machine is illustrated.

Design, Analysis and Model Predictive Control of an Axial Field Switched-Flux Permanent Magnet Machine for Electric Vehicle/Hybrid Electric Vehicle Applications

In this paper, an axial field switched-flux permanent magnet (AFSFPM) machine with stator-PM, which has a high power/torque density and efficiency feature as well as shorter axial length, is designed, analyzed and controlled. The topology, operating principle and design procedure of the AFSFPM machine are labored and discussed. The electromagnetic performance, including the flux linkage, back-EMF, cogging torque, winding inductance and field-control capability, are studied based on 3-D finite-element analysis (FEA). In order to investigate the operating performance of the machine in the whole speed range, a continuous-control-set model predictive control (MPC) method for the AFSFPM machine is proposed. Based on the stage control targets, the maximum torque per ampere (MTPA) and maximum output power flux-weakening strategies are presented in constant torque and constant power regions, respectively. Finally, a prototype of AFSFPM machine has been manufactured and experimentally evaluated and the results show that the MTPA strategy increases the load capability and the flux-weakening strategy broadens the constant power operation range. Moreover, the anti-load-disturbance capacity and dynamic response performance are improved under the MPC method. As a result, the proposed AFSFPM machine drive system is excellent alternative for electrical vehicles (EVs) or hybrid EVs (HEVs).

Development of Dual-memory Motor Drives for Electric Vehicles

AbstractThis paper proposes a dual-memory motor drive for electric vehicles (EVs). The dual-memory motor adopts a dual-magnet arrangement which incorporates two permanent magnet materials for hybrid excitation, namely neodymium-iron-boron (NdFeB) and aluminum-nickel-cobalt (AlNiCo). The NdFeB PMs provides the main air-gap flux, while the AlNiCo PMs can be regulated online for main flux strengthening or weakening. Therefore, the dual-memory motor drives can achieve a high starting torque by flux strengthening and extend its constant power operation range by flux weakening. Firstly, the proposed motor structure is presented. Secondly, its operation principle is discussed. Thirdly, the drive system and control scheme are developed for EVs. Finally, by using the circuit-field-torque time-stepping finite element method (CFT-TS-FEM), the performance of flux strengthening is verified, and experiments are also carried out to assess its flux weakening capability.

Electronic pole changing technique of multiphase induction motor based on vector control

SUMMARY In order to extend the range of a constant-power operation regulation of the AC drive system, the electronic pole changing (EPC) technique for multiphase induction motor (IM) is proposed based on multiphase system transformation theory and the vector control (VC). This proposed technique can extremely expand a constant-power operation range without increasing the volume or current of an IM. The harmonic currents are generated in different orthogonal planes by VC to realize EPC without the poweroff. The EPC process is continuous and smooth, and the torque impulse is not obvious. An EPC experiment of a nine-phase IM is demonstrated in this paper. The experimental results verify that the proposed EPC technique has the ability to extend the operation range of multiphase IM. Copyright © 2012 John Wiley & Sons, Ltd.

Design and Finite-Element Analysis of Interior Permanent Magnet Synchronous Motor With Flux Barriers

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The paper presents a finite-element method-based design and analysis of interior permanent magnet synchronous motor with flux barriers (IPMSMFB). Various parameters of IPMSMFB rotor structure were taken into account at determination of a suitable rotor construction. On the basis of FEM analysis the rotor of IPMSMFB with three-flux barriers was built. Output torque capability and flux weakening performance of IPMSMFB were compared with performances of conventional interior permanent magnet synchronous motor (IPMSM), having the same rotor geometrical dimensions and the same stator construction. The predicted performance of conventional IPMSM and IPMSMFB was confirmed with the measurements over a wide-speed range of constant output power operation. </para>

Design and Analysis of an Interior Permanent Magnet (IPM) Machine With Very Wide Constant Power Operation Range

This paper evaluates the design of a new segmented interior permanent magnet (SIPM) machine with very wide constant power operation range. The machine uses segmentation of the rotor magnets with the help of iron bridges between magnet segments. This provides for an inherent flux-weakening capability to the interior permanent magnet (IPM) machine. A very wide flux-weakening range has been achieved by using a standard distributed stator winding only. The flux-weakening capability of the proposed SIPM motor was compared to a conventional IPM machine. The same stator was used in both machines for direct comparison. The paper also presents the design optimization process and experimental verification of the performance of the proposed machine as a case study of a 42 V alternator operation in which the speed range is from 600 to 6000 r/min.

Analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation

The paper presents the analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation. The analysis is based on finite element method and uses the information on local flux density variation in the motor components. The total iron loss is calculated by summing up separately the hysteresis, classical eddy current and excess losses for each element of discretization over one electrical cycle of magnetic field variation in all parts of motor iron. The results of iron loss calculation were compared with the results obtained from experiments on the actual machine.

Transient performance analysis of a six-phase pole change induction motor for electric vehicles

We previously proposed a six-phase pole change induction motor (six-phase PCIM) for electric vehicles (EVs), and have presented its operating principle and steady state characteristics. The six-phase PCIM expands the constant power operation range using the pole change technique without mechanical contactors; therefore it possesses superb characteristics for miniaturizing EV driving systems. This paper proposes a new analysis method for the six-phase PCIM in order to derive basic equations which can be used to analyze transient phenomena caused by pole change and to create control methods. First, a “six-phase tensor-transformed rotational d-q axis” is defined and its physical meaning made clear. By using this axis, voltage and torque equations which can uniformly deal with the steady state and transient states will be derived. Next, we compare measured and simulated results of voltage, current, and torque characteristics in steady state and in transient states at the pole change operation and both-pole dual operation. Through these comparisons, the validity of our theory and its effectiveness to performance analysis and application to the control method for the six-phase PCIM is discussed in detail. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(2): 59–71, 1997

Basic principle and maximum torque characteristics of a six-phase pole change induction motor for electric vehicles

In addition to basic characteristics such as small size, lightweight and easy maintenance, the electric vehicle (EV) motor is required to possess characteristics that allow for the production of high torque in low-speed region and to realize a wide-speed range of constant power in high-speed region. In an attempt to improve further the constant power operation of the induction motor (IM), this paper proposes a six-phase pole change IM (six-phase PCIM). The six-phase PCIM further expands the constant power operation range without increasing either volume or current of IM. To clarify the basic principle and torque characteristics of the six-phase PCIM, its winding method and distribution of magnetomotive force (mmf) will first be examined. Then, by establishing a performance calculation method based on a quasisinusoidal wave method, the feasibility of a highly precise performance calculation sufficient for actual use will be demonstrated. Furthermore, by clarifying through experiment the maximum torque characteristics, the feasibility of expansion of the constant power operation range will be confirmed and its effectiveness in the EV will be discussed. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (3): 78–91, 1997

A Control Method of an Inverter-Fed Six-Phase Pole Change Induction Motor for Electric Vehicles.

In attempt to improve the constant power operation properties of the induction motor (hereafter, IM) for electric vehicles, we have developed a six- phase pole change IM (hereafter, six-phase PCIM). The six- phase PCIM can expand the constant power operation range without increasing the volume and current of IM. This advantage is realized by making use of the difference of the IM's maximum torque in the dissimilarity in the number of poles.This paper can be summarized as follows:A six- phase PCIM which can be operated as 4-pole and 8-pole is smaller than a 4-pole IM with the same rating.The method of vector control based on the six- phase to two pairs of rotational d- q axis transformation is established.When a six-phase PCIM is operated with a six-phase inverter, a mechanical contactor to change the number of poles is not necessary and the pole change is carried out automatically at the proper speed.The pole change can be done smoothly without the large torque variation by the technique of controlling the flux levels of both modes independently.The characteristics of the proposed control method are shown through the simulations and experimental results, and the usefulness of this control method for the electric vehicle drive system is made clear.

Electric Vehicle Related Technologies. Basic Principle and Maximum Torque Characteristics of A Six-Phase Pole Change Induction Motor for Electric Vehicles.

In addition to basic characteristics such as a small size, light weight and easy maintenance, the electric vehicle (EV) motor is required to possess characteristics which allow for the production of a high torque at a low speed region and to realize a wide range of constant power operation at a high speed region.In an attempt to further improve the constant power operation properties of the induction motor (IM), this paper proposes a six-phase pole change IM (six-phase PCIM). The six-phase PCIM further expands the constant power operation range without increasing the volume and current of IM.To clarify the basic principle and the torque characteristics of the six-phase PCIM, first, its winding method and distribution of mmf will be examined. Next, by establishing a performance calculation method based on quasi-sinusoidal wave method, the feasibility of a highly precise performance calculation sufficient for actual use will be demonstrated. Furthermore, by clarifying the maximum torque characteristics through experiment, the feasibility of the expansion of the constant power operation range will be confirmed and its effectiveness in the EV will be discussed.

Transient Performance Analysis of A Six-Phase Pole Change Induction Motor for Electric Vehicles.

We have already proposed a six-phase pole change induction motor (six-phase PCIM) for electric vehicles (EV), and have been making clear about its operation principle and steady state characteristics. The six-phase PCIM further expands the constant power operation range using the pole change technique without mechanical contactors, therefore it possesses the superb characteristics to miniaturize the EV's driving systems.This paper proposes a new analyzing method for the six-phase PCIM in order to derive the basic equations which can be utilized to analyze the transient phenomena caused by pole change and to create the control methods. First, a “six-phase tensor-transformed rotational d-q axis” (provisional name) will be defined, and its physical meanings will be made clear. By using this axis, the voltage and torque equations which can uniformly deal with the steady state and the transient state will be derived.Next, comparative examinations between the measured results and the simulated results regarding the voltage, current and torque characteristics on the steady state and the transient state at the pole change operation and the both poles dual operation will be achieved. Through these examinations, the propriety of this theory and its effectiveness in the further detail performance analysis and the application to the control method for the six-phase PCIM will be discussed.

Variable Speed Drive System of Permdnent Magnet Synchronous Motors with Flux-weakening Control.

Permanent magnet synchronous (PM) motors are widely used for industrial applications. In traction and spindle drives, the constant power operation and wide speed range are desirable. With DC motor drives, these are achieved by the appropriate reduction of the field current as the speed increases. In the PM motor, the direct control of magnet flux is not available. The air-gap flux, however, can be weakened by the direct axis armature reaction. This control technique is called “flux-weakening” instead of “field-weakening”. This paper describes a variable speed drive system of PM motor for the constant power and wide speed range operations. In the proposed control system, a novel flux-weakening technique is applied. The current vector is controlled so that the maximum torque per armature current can be obtained at low speeds and the terminal voltage is kept within its limited value at high speeds. The control performances are examined by the simulations and the experimental results.