Brushless AC Motor Research Articles

A Machine-Learning-Based Interturn Short-Circuit Diagnosis for Multi-Three-Phase Brushless Motors

Over the past few years, Artificial Intelligence (AI) techniques have become one of the most exciting technologies of our age. This fascinating field paves the way for new possibilities and extends to almost all areas of industry and research. This paper illustrates a Short-Circuit (SC) diagnosis strategy for a multi-three-phase brushless AC motor drive based on Machine Learning (ML). A thorough model of the electrical machine is obtained through specific finite-element simulations and used to replicate various fault scenarios. This model quickly yields a large amount of data, which is then employed for training the ML algorithms. Once trained, the ML models are tested, with experimental data directly obtained from a prototype of multiphase drive, to verify the effectiveness of the diagnostic algorithms. The ML algorithms allow monitoring the health condition of the machine, distinguishing and localizing two types of faults, i.e., inter-turn SCs and Extra Turns (ETs), placed in different coils of the machine.

Curving Motion Control of a Traction Rail Mover Using a Dual BLAC Motor Drive

This article presents an improved position control method of an overhang-type rail system considering a curved path. The designed system is driven by two BLAC (brushless ac) motors, and the moving position is controlled based on the signal from a simple Hall position sensor mounted on the motor without any absolute position sensors. The rail is composed of both linear and curved paths. For the linear rail, the two motors are controlled to rotate in the same speed. However, in a curved path, the two motors must have different moving distance according to the curvature. Generally, in order to determine the proper motion commands for both traction motors, the actual curvature state and position have to be detected by a potentiometer or an encoder equipped with linear position sensor, but this method significantly increases complexity and cost of the system. This article aims to solve this problem by using a low-cost semiconductor IMU (inertia measurement unit) to estimate the actual rail condition. The IMU will then estimate the heading angle variation to compensate the motion commands for the two BLAC motors without any additional external absolute sensors. As a result, a balanced and improved motion can be achieved for an arbitrary rail path. Practical experiments using an overhang-type rail traction system were performed to verify the effectiveness of the proposed control scheme. The results show the advanced control performance in both linear and curved path, and also a smooth transition between them both.

PTP Tracking Scheme for Indoor Surveillance Vehicle by Dual BLACM With Hall Sensor

This article presents point-to-point tracking error reduction algorithm for indoor surveillance vehicle, which is driven by two in-wheel brushless ac (BLac) motors. In general, in order to control the position, additional equipment such as a separate sensor, camera, or GPS to know the absolute or relative position of the vehicle is required. However, when a large number of sensors or expensive equipment is used, the overall price of the system will also increase, which creates a problem. Also, Global Positioning System cannot be used in indoor systems due to poor signal reception. In the proposed method, the position tracking of the autonomous vehicle only adopts the hall sensor of the traction BLac motors and a gyro sensor on the controller, without any absolute position detecting sensors. From the estimated heading angle by the inertia measurement unit sensor and the calculated moving distance by the hall sensor, the tracking path and actual moving distance errors can be estimated in the proposed method. The actual real-time moving path error is compensated by adjusting the speed and heading angle in the presented control method. Through various experiments, it is verified that the position tracking performance of the indoor autonomous vehicle is improved using the proposed method.

Proposed Commutation Method for Performance Improvement of Brushless DC Motor

This study focused on the efficiency improvement and acoustic noise reduction of brushless DC (BLDC) motors by reducing current harmonics using a novel BLDC commutation method. To achieve these goals, we designed an improved 150° commutation method for a three-phase permanent magnet BLDC motor that can improve the current waveform. Although the 120° commutation method is generally employed for BLDC motors, an improved 150° commutation method is introduced to operate the BLDC with increased efficiency and acoustic noise similar to a brushless AC motor. This study investigated the attributes of various commutation methods, both theoretically and experimentally, to determine the optimal commutation method. The results of this study indicate that the improved 150° commutation method is optimal in terms of harmonic attributes and reduced torque ripple, allowing it to improve motor efficiency and reduce acoustic noise.

Motion control of the rail traction system by dual brushless AC motors using a disturbance observer

This study presents an accurate motion control scheme using a modified non-linear disturbance torque observer for a rail traction system driven by a dual brushless AC (BLAC) motor. The target application has two BLAC motors mounted on the top surface of the rail. The mover translation along the rail is handled solely by the traction motors without any external sensor. In the low-speed range, however, the conventional disturbance torque observer is unstable due to the resolution of the Hall sensor and speed detection delay. To solve this instability problem, a simple weight function with the synchronisation of torque current and the delayed speed feedback is added to the proposed torque observer. This way, zero output can be created in the selected speed region for stabilisation and torque current can be compensated. Furthermore, simple balance error compensation to synchronise both motors is added to the proposed speed and position model reference adaptive control scheme. The experiments were performed to verify the proposed control method. The results show advanced performance with reduced position and balance errors between the two BLAC motors and an improved overall control performance of the rail mover.

Design and Analysis for Higher Torque Constant of Brushless Motor for High Volume Low Speed Fan

This paper deals with the design and analysis for torque constant characteristics of Brushless AC motor (BLAC) for High Volume Low-Speed Fan (HVLS). The torque constant characteristic of a BLAC motor is important to ensure higher torque performance concerning the input current. Through a previous study, the necessity of torque constant characteristic of BLAC to achieve optimum performance motor is still limited. Therefore, this paper aims to analyze the torque constant characteristic of BLAC for HVLS fan applications. Three models of BLAC motor with finite permanent magnet volume and magnetomotive force (MMF) have been simulated in order to evaluate the performances of BLAC motor. Commercial Finite Element Analysis (FEA) known as Flux 2D has been used to compute the back-electromotive force (Back-EMF), cogging torque, and transient torque in order to analyze the torque constant characteristic of different slot and pole numbers. As a result, the design of the BLAC motor for 18/20 has been chosen due to higher torque constant compared to others. As a conclusion, this research provides guidelines and an overview of designing a BLAC motor for HVLS fan application.

Sensorless Combined Control of In-wheel BLAC Motors for Mobility Scooter

This paper presents a speed control for in-wheel brushless AC (BLAC) motors using a simple hall sensor to improve steering and driving performance of mobility scooters. To achieve smooth steering and motion controls, the sensor-sensorless combined estimation method is proposed. Furthermore, a modified current model reference adaptive system (MRAS) is also proposed to increase the dynamic response and estimation accuracy. The dead-time effect is directly compensated to improve the sensorless performance in the lower speed region. From standstill to the controllable minimum speed region, fast open-loop control method is applied to the traction motors. The vehicle velocity is then controlled using the speed information obtained from the proposed sensorless-sensor combined estimation scheme. To verify the effectiveness, a prototype mobility scooter was manufactured and the proposed control method was tested. Experiment results shows that the steering and motion of the vehicle are improved and the overall performance is increased compared to that of the conventional driving method.

Simulation of Brushless DC Motor Drive System

Brushless DC motor has the operating characteristics of DC motors, and also has the advantages of brushless AC motor. It has the advantages of small size and light weight, so they are widely used in various industrial applications. In this paper, for brushless DC motor simulation, it introduces its working principle and mathematical model, using the six-step inverter to ensure the normal operation of the motor ,with closed-loop speed structure to ensure steady-state and dynamic performance, enhanced its reliability.

Design and Position Control of Overhang-Type Rail Mover Using Dual BLAC Motor

This paper presents the design and position control scheme of an overhang-type rail mover system driven by a dual Brushless AC (BLAC) motor with a simple Hall position sensor inside each motor. The overhang-type roller is chosen to reduce the slip between the roller and rail surface due to gravity. The BLAC motors are used to provide smooth translation along the rail and effective turning. Imbalances on any part of the motor and the simplicity of the Hall position sensor can create additional disturbance load, unsteady movement, and position errors. To reduce the sudden moving position error between the two motors, a balancing compensator with a Proportional-Differential (PD) position controller, which is based on the instantaneous speed and position trajectories, is presented. Furthermore, speed and position reference models are designed to compensate for the low Hall sensor resolution in the low-speed range. Therefore, steady-state position errors can then be regulated simply by using the instantaneous speed and position information. Experiments were performed to verify the viability of the proposed system and control. The results show a significant improvement in roller translation along the rail and stopping position accuracy.

System‐level optimal design process of inverter‐fed BLAC motor used for 12–48 V integrated electric brake system

In this study, to maximise the performance and efficiency of 48 V integrated electric brake (IEB) system, a system-level optimal design process is proposed for inverter-driven brushless AC (BLAC) motor, taking into account the available input voltage that varies depending on the motor operating conditions. To get available input voltages, the voltage drops of battery wiring and inverter are reversely calculated from the motor output power. In the optimal design process, the resistance components in the inverter are separated into DC and AC parts, and these are analysed by including the dq equivalent circuit for motor analysis. The battery currents are obtained using the calculated maximum output performance and the loss between the battery and inverter. The proposed design process is applied to the optimal design of the 48 V motor for IEB systems. Also, to reduce the development cost of the 48 V motor, the manufacturing tools of the previously developed 12 V motor are shared. As an optimal design results, it is confirmed that there is an efficiency improvement effect of ∼5% compared to the conventional design of 12–48 V BLAC motor.

AC losses test of HTS racetrack coils for HTS motor winding

Current work is dedicated to determination of AC losses of racetrack coils that are intended to be used in HTS motor winding. Coils were tested at temperature of boiling nitrogen with sine waveform current with frequencies from 50Hz to 200Hz and corresponding levels were taken as a basis for comparison. Current waveforms, distinctive for brushless DC and brushless AC motors, induced by high-frequency modulation, were compared. Two coils with same dimensions and numbers of turns, but with different tapes (AMSC/SuperOx) were compared in terms of the levels of losses on described current forms.

Optimization of surface-mounted permanent magnet brushless AC motor using analytical model and differential evolution algorithm

Abstract This paper discusses the optimization of surface-mounted permanent magnet brushless AC (PMBLAC) motor using Analytical Sub-domain model with Differential Evolution Algorithm (ASDEA). Only two regions were considered in this analytical sub-domain model, ie magnet and airgap regions, with assistance of Complex Relative Permeance Function (CRPF) to account for the stator slotting effect. Five machine parameters were chosen to be optimized, namely the magnet arc-pole-pitch ratio, slot opening width, magnet thickness, airgap length and stator inner radius. The optimization process has four objectives, ie minimum torque ripple, low cogging torque, high efficiency, and high output torque. The results from the optimized ASDEA were compared with the Analytical Sub-domain Genetic Algorithm (ASGA) and further validated against 2-D finite element model (FEM). Results show a good agreement between analytically optimized models and finite element model. The ASDEA has faster computational time compared to ASGA, and this provides benefit in terms of reducing the machine design parameterization time and less redundancy work required to achieve motor design specifications.

Design of Low-Cost BLAC Motors for Integrated Electric Brake Systems

During motor production processes, the influence of motor manufacturing tooling costs on motor prices is mostly negligible and considered to be insignificant. The manufacturing cost, particularly the molding cost, may not be a significant issue for mass production, but it would become a crucial issue for modern small-scale application-oriented design. When the total number of motors produced per motor manufacturing tool such as stator and rotor pressing tool is reduced, the effect of the motor manufacturing tool cost on the motor price can be greatly increased. To reduce the cost, we present a new design approach of a brushless AC (BLAC) motor that shares motor manufacturing tools, unlike many previous studies on low-cost designs. The design approach of a BLAC motor is applied to integrated electric brake (IEB) systems of various specifications. In addition, to analyze the motor performances in IEB systems, the BLAC vector control system, FEM, design of experiment, and moving least square method are used. Furthermore, to predict the available operating time of a motor, a heat compensation coefficient that uses the experimental data of an existing motor is proposed. By implementing this design approach, we have effectively designed motors that satisfy performance requirements such as speed response, available operating time, and total harmonics distortion (THD) of back EMF with minimum stator core volume, in the IEB systems, and achieve a 25.5% reduction in cost through sharing of motor manufacturing tools.

Fuzzy-Variable Gain PI Mode Control Applied to a Brushless AC Motor Drive

More strategies were developed to control a Brushless Motor’s Speed. Among them, vector control is one of widely used. Variable Gain PI controller is developed and gives a performed control result. Fuzzy logic control is proposed to optimize the control system. In this paper, the system combines the performance of the Variable Gain PI and fuzzy logic controllers. All these strategies were simulated with Matlab and Simulink for comparison. Behind this, the main objective is to improve the best performance of the Fuzzy-Variable Gain PI mode control applied to a Brushless AC Motor drive where implementations, to an MSK23335 Board with a PM50 module and a 90W BLAC Motor, are shown to improve the result.

New Approach to a Hybrid Fuzzy-Sliding Mode Control to a Brushless AC Motor Scheme

New Approach to a Hybrid Fuzzy-Sliding Mode Control to a Brushless AC Motor Scheme - written by F. Philibert Andriniriniaimalaza , N. Jean Razafinjaka , C. Bernard Andrianirina published on 2018/07/30 download full article with reference data and citations

Field Weakening Characteristics Computed with FEM-Coupled Algorithms for Brushless AC Motors

Finite Element Method (FEM) analysis tools are the most adopted in the design of brushless alternating current motors due to the advantage of considering multi-physics effects with dependencies of variables such as cross-coupling, saturation and others that are not possible to be modeled analytically with high precision. During the design process designers compute operation points such as maximum torque per ampere or flux weakening characteristics that cannot be targeted directly on the FEM tool. Therefore, designers make a sweep of simulations and post-processed the data in order to obtain the results, this is repetitive particularly in the conceptual phase of the design where features of the motor are still not defined. This paper presents nine algorithms as an alternative to compute with iterative methods operation points that cannot be targeted directly on a FEM tool. The algorithms must be coupled to the FEM tool and can compute complex points such as the characteristic current and modes of operations limits within acceptable range of error and times of execution for practical purposes. Validation of the algorithms using Jython is presented with results for the three types of brushless motors (non-salient, interior permanent magnet and reluctance motor).

A study on the speed control of a BLAC motor by feedforward compensation of the back‐EMF using a fuzzy algorithm

Back electromotive force (back‐EMF) feedforward compensation is used to improve the control performance of a brushless AC (BLAC) motor. The back‐EMF has a speed component, and the response is slow when the back‐EMF is compensated for by the speed. The back‐EMF feedforward compensation does not operate exactly when the speed fluctuation is severe. To solve these problems, the back‐EMF is compensated by the speed of the motor operation, which is calculated by the proposed method. The speed and the delta speed are the input membership functions of the fuzzy system. The weighting used to estimate the speed is defined as the output membership function of the fuzzy system. The speed is estimated exactly using 15 rules of the fuzzy system, and the back‐EMF feedforward compensation operates using the estimated speed. The membership function and the fuzzy rules are adjusted using simulation. The root‐mean‐square (RMS) value of the error between the real speed and the reference speed is measured. It is confirmed that the performance is excellent when the back‐EMF is compensated by the speed, which is estimated by the proposed algorithm. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Steady-State Modeling and Analysis of a Double-Sided Interior Permanent-Magnet Flat Linear Brushless Motor With Slot-Phase Shift and Alternate Teeth Windings

Analytic modeling techniques of a double-sided interior permanent-magnet flat linear brushless motor (IPM-FLBM) with slot-phase shift and alternate teeth windings are proposed in this paper. Since the buried-type IPM-FLBM with the slot-phase shift and alternate teeth windings is fairly new compared with conventional linear motors, little research has been previously done in modeling and analysis. The analytic models presented in this paper provide the effective and reliable methods for this new type of linear motor. For this purpose, a simplified magnetic equivalent circuit and superposed winding function are investigated. A variable winding function is newly developed in order to evaluate the inductances of the salient motor with the alternate teeth windings. All analytic models are verified with 3-D finite-element analyses (FEAs) step by step. The steady-state thrust force is modeled using a classical closed-form solution for linear brushless ac motors. The static end-effect and cogging forces for the ripple force evaluation are investigated using FEA. The validities for performance parameters are demonstrated experimentally.

Motor Design and Characteristics Comparison of Outer-Rotor-Type BLDC Motor and BLAC Motor Based on Numerical Analysis

In this study, we dealt with the design and characteristics of an outer-rotor type motor applied for the blower system of a vehicle according to a brushless dc motor (BLDCM) and a brushless ac motor (BLACM) through finite element analysis (FEA). In order to guarantee proper back electromotive force (BEMF) waveforms for each model, 8-pole/12-slot and 16-pole/12-slot types were applied to a BLDCM and a BLACM, respectively. Furthermore, we designed and analyzed all models based on a 3-D FEA to consider the 3-D effect of the end-plate of the rotor core. As a result, the BLACM was verified as having an advantage in the reduction of torque ripple and motor size, under identical current density conditions, considering the driving method. Finally, we suggest a 4-parallel delta-winding for a 12-slot motor to improve the winding usability.

Optimal rotor shape design of 3-step skew spoke type BLAC motor to reducing cogging torque

In electric power steering (EPS), spoke type brushless ac (BLAC) motors offer distinct advantages over other electric motor types in terms of torque smoothness, reliability and efficiency. This paper deals with the shape optimization of spoke type BLAC motor, in order to minimization cogging torque. In this paper examines, 3 step skewing rotor angle, optimizing rotor core edge and rotor overlap length for minimize cogging torque in spoke type BLAC motor. The methods were applied to existing machine designs and their performance was calculated using finite- element analysis (FEA). Prototypes of the machine designs were constructed and experimental results obtained. It is shown that the FEA predicted the cogging torque to be nearly reduce using those method.