China
Africa
Explore chapters and articles related to this topic
Electric Machines
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
An electric machine is an electromechanical device used for energy conversion from electrical to mechanical and vice versa. In a vehicle system, the electric machine can be designed to process supplied energy and deliver power or torque to the transaxle for propulsion. The machine also processes the power flow in the reverse direction during regeneration when the vehicle is braking converting mechanical energy from the kinematics into electrical energy. The term ‘motor’ is used for the electric machine when energy is converted from electrical to mechanical and the term ‘generator’ is used when power flow is in the opposite direction with the machine converting mechanical energy into electrical energy. The braking mode in electric machines is referred to as regenerative braking. There are electrical, mechanical and magnetic losses during the energy conversion process in either direction in an electric machine, which affect the conversion efficiency. Some energy is always lost from the system for any energy conversion process. However, the conversion efficiency of electric machines is typically quite high compared to that of other types of energy conversion devices.
D.c. Machines
Published in John Bird, Newnes Engineering Science Pocket Book, 2012
The efficiency of an electrical machine is the ratio of the output power to the input power and is usually expressed as a percentage. The Greek letter, η (eta) is used to signify efficiency and since the units are powerpower, then efficiency has no units. Thus efficiency,η=(outputpowerinputpower)×100%
D.c. machines
Published in John Bird, Electrical and Electronic Principles and Technology, 2017
The efficiency of an electrical machine is the ratio of the output power to the input power and is usually expressed as a percentage. The Greek letter, ‘η’ (eta) is used to signify efficiency and since the units are power/power, then efficiency has no units. Thus efficiency,η=(outputpowerinputpower)×100%
Model Predictive Torque Control-Based Induction Motor Drive with Remote Control and Monitoring Interface for Electric Vehicles
Published in Electric Power Components and Systems, 2023
Aydın Boyar, Ersan Kabalcı, Yasin Kabalcı
DC and AC electric machines, which are frequently used for EVs, are among the various electric machine types used in industrial applications. Permanent magnet synchronous machine (PMSM) and AC induction machine (ACIM) are the most commonly used AC-type machines in EVs. The main benefits of ACIMs are their low cost, low maintenance, and simple control features. They can be operated at a variety of speed and torque levels. In EVs, the DC voltage stored in the battery is converted to AC voltage by an inverter and used to supply the electric machine [6]. Inverter topologies are classified into two types as conventional two-level and multilevel configurations. Multilevel inverters (MLIs) provide advantages such as higher power density, higher efficiency, lower voltage stress on semiconductor devices, and improved waveform quality that make them an appealing option for EVs [7]. However, they have some disadvantages including complicated switching states and increased system costs due to the increased number of switches. The three main types of MLI topologies are the cascaded H-bridge (CHB), flying capacitors (FC), and neutral point clamped (NPC) inverters. The CHB inverter structure needs isolated DC sources for each leg of the H-bridge while the FC inverter needs complex control for proper operation due to the capacitors used for energy storage and transfer. Therefore, CHB and FC topologies are not widely used in industrial applications such as motor drives because of these drawbacks, [8].
Robust Control of the Brushless DC Motor with Variable Torque Load for Automotive Applications
Published in Electric Power Components and Systems, 2020
Alejandra de la Guerra, Luis Alvarez-Icaza
The electric machines considered for transportation applications are the Direct Current (DC) motor, the Induction Motor (IM), the Permanent Magnet Synchronous Motor (PMSM) and the Switched Reluctance Motor (SRM). When selecting the appropriate type of motor for a given application, reasonable cost and market penetration are key factors. The Brushless DC motor (BLDC) motor is a type of PMSM that complies with requirements related to power density and efficiency in transportation applications, as has been stated by Refs. [3] and [4]. These type of motors has good market availability and low cost of the associated power driver technology. However, its main drawback is that the fixed permanent magnet limits its constant power region.