China
Africa
Explore chapters and articles related to this topic
Propulsion Systems
Published in Dorin O. Neacşu, Automotive Power Systems, 2020
Since the actual propulsion involves an electric motor, the selection and design of the electric motor drive is very important. Depending on the size of the vehicle, the electrical motor generally needs to deliver in between 45 kW (60 HP) and 150 kW (200 HP). Due to reliability and efficiency concerns, a brushed dc motor is rarely used. Furthermore, such high-power levels can be achieved easier with three-phase ac machines, which can be induction motors, synchronous motors, permanent magnet (brushless dc motors), or switched reluctance motors. Any of these motors can be a possible solution and actually used in vehicle propulsion applications. Using an ac motor requires a power converter for supplying sinusoidal currents out of the dc battery and distribution bus.
Brushed-DC Electric Machinery for Automotive Applications
Published in Ali Emadi, Handbook of Automotive Power Electronics and Motor Drives, 2017
Electric motors have played a crucial role in the evolution of the automotive industry. Existing trends in more electrification of automobiles indicate a further increase in deployment of electromechanical energy devices in coming years. Due to historical, technical, and economical incentives DC-brushed machines have been the favorite choice for numerous automotive applications ranging from starters to auxiliary devices. Ease of control, capital investment, and relatively low cost of manufacturing compared to other energy conversion devices are among the main reasons to justify the substantial use of DC-brushed machines, as advanced motor drive technologies emerge. Although maintenance and durability are still considered as main impeding factors, an impressive compactness and relative high efficiency seems to be of higher significance in the automotive industry. Introduction of power electronics into automotive products over the past two decades has further paved the road for high-grade performance and flexibility in four-quadrant applications. However, it must be mentioned that DC-brushed motor drives are primarily employed for smaller size motors; hence, the design practices should be done in the context of the application to maintain engineering and commercial sense. This necessitates an investigation of drive performance in the presence of the high temperatures that are typical in automotive applications. The present chapter provides an overview of the fundamentals, magnetic design, and control practices for DC-brushed motor drives. Due attention is given to permanent magnet DC-brushed motor drives, as they represent the dominant magnetic configuration used in most automotive DC-brushed motors.
UAS Subsystem Nexus: The Electrical System
Published in Douglas M. Marshall, R. Kurt Barnhart, Eric Shappee, Michael Most, Introduction to Unmanned Aircraft Systems, 2016
Brushed motors can operate directly on source DC, and motor speed can effectively be controlled by increasing or decreasing the strength of the magnetic field by using a variable resistance to vary the intensity of the current flowing in the windings. In comparison to brushless designs, the control of brushed motor rpm is much more easily achieved. However, brushes produce friction that increase heat and reduce output power, constantly wear and will eventually require replacement. Significantly, the interface of the brushes and commutator is a source of potential arcing that may cause EMI and corrosion. In addition, the brushes are made of carbon, a semiconductor material having a measure of inherent resistance that reduces the overall efficiency of the motor. As will be subsequently described, brushless motors control the timing and orientation of the associated magnetic fields by what might be referred to as electronic commutation—no brushes, no segments, and no arcing. Brushless motors offer greater reliability, operate more quietly, and afford greater specific torque and thrust. BLDC propulsors also provide more torque per ampere of consumed current. In the nineteenth century, remotely piloted unmanned aircraft (e.g., the Radio Queen and the Magicfly) were powered by brushed motors. Not until improvements in the transistor design and microprocessor technology permitted, around the onset of the millennium, the economic miniaturization of the necessary controlling micro-circuitry (in the form of an electronic speed control, ESC) did the widespread use of brushless motors in sUAS propulsors became possible (Büchi 2012). Although small, brushed motors (e.g., the RS 540 and Speed 600) continue to be available for hobby RPA, the advantages of brushless motors dictate their pervasive use in electrically powered UASs.
Developments and clinical evaluations of robotic exoskeleton technology for human upper-limb rehabilitation
Published in Advanced Robotics, 2020
Akash Gupta, Anshuman Singh, Varnita Verma, Amit Kumar Mondal, Mukul Kumar Gupta
Of the above-listed actuators, Electric Motors are the commonest choice [1,76] due to their ease of control, actuation, maintenance, compactness, and portability. However, they are held back because of the high impedance values. The pneumatic actuators composed of the pneumatic cylinder offers high power to weight ratio if the weight of the compressor unit required for cylinder actuation is not considered. The hydraulic actuators are the most powerful among the above mentioned, but it is relatively heavier and suffers from fluid leakage problems, which is not suitable for rehabilitation application. Another innovation in the field of actuators is pneumatic muscle actuators [77]. These actuators have a very good power/weight ratio like pneumatic actuators and exhibit the properties of the human muscle system [78]. They are light and transfer force in a single direction with the help of internal rubber structure and braided mesh shell [1]. Electric motors are the most widely used actuators in upper and lower limb exoskeletons due to their reliability, favorable torque to weight ratio, high speed, good overloading capacity, and precision. There are two types of electric actuators: AC motors and DC motors, mostly brushless. Because permanent-magnet motors provide high torque despite the motor shaft being stationary, they are preferred by most in the industry. In the case of mobile exoskeleton devices, a lightweight motor is ideal to use. Brushed DC motors provide high torque, high efficiency, and performance [79].
Multi-Objective Modified Imperialist Competitive Algorithm for Brushless DC Motor Optimization
Published in IETE Journal of Research, 2019
MohammadAli Sharifi, Hamed Mojallali
A DC motor is a kind of electrical machine that converts direct current electrical power into mechanical power. The most common types rely on the forces produced by magnetic fields. In order to have a more reliable, more efficient, and less noisy operation, brushless DC (BLDC) motors have been introduced. BLDC motors are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor. They have been successfully used in electronic, computer, and automotive applications [1–4]. Compared to the brushed motors with the same power output, they are more efficient and lighter and also require less maintenance due to absence of brushes. In addition, they are more versatile mainly because of their ability in the speed and torque domain [1–4]. The motor presented in this work is a wheel motor which propels a solar vehicle during a race. Materials and manufacturing costs are not essential while the motor efficiency and the axial bulk are the key points [5]. In this paper, an analytical model of BLDC motor is used as a benchmark composed of 78 nonlinear equations implemented with five design variables and six inequality constraints [5]. In other words, the design process is estimating five parameters to maximize efficiency, minimize the total mass, and also satisfy six inequality constraints simultaneously. To achieve these objects, a multi-objective optimization technique is required.
A periodic adaptive controller for the torque loop of variable speed brushless DC motor drives with non-ideal back-electromotive force
Published in Automatika, 2022
In recent years, there has been a sustained increase in demand for brushless direct current (BLDC) motor drives for industrial application areas such as automotive, aerospace, medical equipment, home appliances. Their increasing popularity is due to their high efficiency and reliability, as well as other attractive features including long life, higher power-torque density, and drive simplicity. Generally, the differences of brushless motors from brushed motors can be listed as high speed and high torque efficiency, quiet operation, and ease of maintenance. The BLDC motor is a type of synchronous motor with permanent magnets on the rotor and with trapezoidal-like back-EMF.