Low-speed High-torque Motor Research Articles

Loss Study of Dual Stator Low Speed High Torque Synchronous Motor with Hybrid Rotor

Low speed and high torque machines are widely used in industrial production, oilfield mining, wind power generation, etc. Low speed high torque motors have large internal space, in order to make full use of internal space this paper proposes a dual stator low speed high torque synchronous motor. The rotor adopts a surface-mounted permanent magnet rotor structure on one side, and a spliced reluctance rotor structure on the other side. A magnetic ring is added in the middle to make permanent magnet and magnetic resistance independent of each other. The motor has a special structure, and the loss distribution is different from that of a normal motor. The loss will affect the performance of the motor. This paper establishes the iron loss model considering the effects of alternating magnetic field, rotating magnetic field, and harmonics. Considering the influence of temperature on copper loss. Then establish a mathematical model of core loss and copper loss. Then studying the motor iron loss and copper loss distribution characteristics. Finally, the results are compared with the finite element method (FEM) to verify the effectiveness of the loss calculation in the paper.

A review: high power density motors for electric vehicles

The review of High Power Density Motor (HPDM) is presented, the high power density refers to ratio of output power to volume of the motor. As a result even a small envelope motor can have high power output. HPDM are also known as low speed high torque motors. The HPDM are compact, lightweight, has high torque and less cogging torque, finding application in automotive field, especially in electric and hybrid electric vehicles. This paper analyses the design, performance and efficiency of various HPDM. Comparative analysis of thirteen different HPDM are reviewed and tabulated for power density, speed, weight, rating and its applications.

Electromagnetic and Structural Design of a Novel Low-Speed High-Torque Motor With Dual-Stator and PM-Reluctance Rotor

The low-speed high torque motor has attracted more and more attention in many fields. The objective of this paper is to investigate the electromagnetic design principle, mechanical structure and cooling system of a novel dual-stator low-speed high-torque motor (DS-LSHTM) with permanent magnet-reluctance hybrid rotor. The proposed motor has the advantages both of the permanent magnet (PM) motor and reluctance synchronous motor. In addition, the greatest feature of this proposed motor is to explicitly separate magnet torque and reluctance torque components so that the two stators can be designed individually with more flexibility. Design principles including electromagnetic characteristics, sizing equation and structure configuration are elaborated. The electromagnetic performance, mechanical properties and temperature rise characteristics of the proposed motor are simulated and analyzed by the finite element analysis (FEA) method. The simulation results show that the rationality of the design and the feasibility of the motor.

Experimental Comparisons Between Modular Multilevel DSCC Inverters and TSBC Converters for Medium-Voltage Motor Drives

This paper makes an intensive comparison in operating performance between a modular multilevel double-star chopper-cells (DSCC) inverter and a modular multilevel triple-star bridge-cells (TSBC) converter. Both inverter and converter are intended to drive medium-voltage motors in industrial applications. First, it makes numerical comparisons, thus, resulting in revealing that the torque and frequency of a driven motor produce a significant effect on capacitor-voltage fluctuation and arm or cluster current in the individual DSCC inverter and TSBC converter. Next, a three-phase DSCC inverter and a three-phase TSBC converter with the same rating as 400 V and 15 kW are designed and compared to drive the following two general purposes and specially-designed induction motors; one is rated at the 380-V, 15-kW, 50-Hz four-pole motor, and the other is at the 320-V, 15-kW, 38-Hz six-pole motor. This experimental comparison based on the two downscaled drive systems confirms the validity of the numerical comparison. Finally, this paper concludes that the DSCC inverter is more suitable for driving medium-voltage high-speed motors loaded with quadratic-torque-to-speed profiles like fans, blowers, pumps, and centrifugal compressors. On the other hand, the TSBC converter is more suitable for driving medium-voltage low-speed high-torque motors like mills, kilns, conveyors, and extruders.

TSBC方式モジュラー・マルチレベル・カスケード変換器（MMCC-TSBC）を用いた低速高トルクモータ駆動

SUMMARY This paper provides an experiment-based discussion on a modular multilevel cascade converter based on triple-star bridge cells (MMCC-TSBC) for a low-speed high-torque motor drive. The TSBC is a direct ac-to-ac power converter capable of achieving bidirectional power flow as well as drawing and feeding three-phase sinusoidal input (supply-side) and output (motor-side) currents with any power factor at both sides. This paper discusses active dc-capacitor-voltage control applied to the low-speed, high-torque motor drive. A specially designed downscaled system combining a 320-V, 38-Hz, 6-pole, 15-kW induction motor with a 400-V, 15-kW TSBC is constructed and tested to confirm the validity of the motor drive. Experimental waveforms obtained from the downscaled system confirm stable operation with the rated load torque across a range from a standstill to the rated speed, including satisfactory start-up performance.

Steady State Performance Analysis of Hydrostatic Transmission System using Two Motor Summation Drive

Hydrostatic transmission (HST) system used in heavy earth moving machineries (HEMMs) has high power density, wide range of speed control and good overall efficiency. Hydrostatically coupled two motor summation drive is an alternative power transmission system, compared to existing closed-loop HST system with low speed high torque motor, used in HEMM. Such drive arrangement has made the possibility to design the transmission system, used in heavy vehicles, in an efficient way to cover wide range of torque-speed demand. This article studies the concept of two motor summation drive and its steady state performance. Experiments have been carried out to analyze the performance of such system. The characteristics of single and two motor drive systems are compared at different load-torque and speed levels. It is concluded that two motor hydrostatic drive systems is more effective at high load-torque and low speed compared to single motor drive system.

Numerical and Experimental Study of Hydrostatic Displacement Machine

This paper presents a simulation tool to determine the structural deflections and corresponding leakage flow in a hydrostatic displacement motor. The simulation tool is applied to a new motor principle that is categorized as an extreme low speed high torque motor with dimensions that calls for attention to the volumetric efficiency. To counteract structural deflections the motor is equipped with compensation pressure volumes that may be used to limit the leakage flow across the end faces of the circular rotor. This leakage flow is investigated by solving Reynolds equation for the pressure distribution across both end faces. The fluid pressure is combined with structural calculations in a fluid structural interaction simulation which evaluates the influence of structural deflections on the gaps and the leakage flow.The numerical work is validated by prototype tests. Both deflections and leakage flows are measured and compared with those from the simulations with good correlation. The deflections, and hence leakage flow, are reduced by the use of compensation pressure volumes, which is validated both numerically and experimentally.

Analysis of a hydrostatic transmission system using low speed high torque motor

In this paper, the performance of a Hydrostatic Transmission system, consisting of a pressure compensated swashplate controlled variable displacement pump and an Orbital Rotor Low Speed High Torque hydrostatic motor has been analysed. Bondgraph modelling technique has been used to study the dynamics of the system. While modelling, the steady state solution of the motor, considered as an input, has been termed as Quasi-static solution. The effect of some critical parameters on the overall performance of the system have been investigated. Using system equations derived from the bondgraph model, the steady state behaviour of the system has been predicted.

Computer-aided design and analysis of direct-driven wheel motor drive

This paper presents the computer-aided design (CAD) and performance analysis of a novel direct-driven wheel brushless DC motor drive for electric vehicles (EVs). The proposed motor is a permanent magnet square-wave motor, whose rotor with rare earth magnets forms the exterior of the motor, which can be fitted with a wheel tire to realize the direct drive for each wheel of an EV. The interior stator with its windings is rigidly mounted onto the suspension and frame structure of the vehicle. In order to achieve the direct drive without any mechanical transmission for EVs, the wheel motor has been designed as a low-speed high-torque motor. The design and optimization of the motor geometry was achieved with the aid of finite-element electromagnetic field analysis. Simulation studies on the transient performance of the motor drive were also carried out. This involved the creation of the motor transient model and formulation of a motor control strategy to ensure the wheel motor drive runs efficiently in the entire permitted speed and load range. The application of CAD techniques in the design of this very unconventional drive is described in this paper.

The Performance of Ball-Piston Multi-Stroke Type Low Speed High Torque Motor : Report No. 1, Experimental Study on Performance of Spherical Surface of Piston

The reliability of the Ball-Piston Multi-Stroke Type Low Speed High Torque Motor is largely influenced by the performance of the spherical bearing of the piston. The friction force and the oil leakage of the spherical bearing in several kinds of pistons were measured by an apparatus specially made for this purpose. A piston which has a wide sliding surface and a leakage controlling restrictor, and a piston designed to support the side force by hydrostatic pressure give a good performance up to the oil pressure of 300 kg f/cm2 and the pressure angle of 35°.

The Performance of Ball-Piston Multi-Stroke Type Low Speed High Torque Motor : 2nd Report, Practical Analysis on Multi-Stroke Type Cam Profile

The Performance of Ball-Piston Multi-Stroke Type Low Speed High Torque Motor : 2nd Report, Practical Analysis on Multi-Stroke Type Cam Profile

ボール・ピストン式多行程形低速高トルクモータの特性に関する研究 : 第1報、ピストンの球面軸受部の負荷特性に関する実験的研究

ボール・ピストン式多行程形低速高トルクモータの特性に関する研究 : 第1報、ピストンの球面軸受部の負荷特性に関する実験的研究