Concentrated Windings in Compact Permanent Magnet Synchronous Generators: Managing Efficiency

Abstract

Abstract:In electric power generation, customers want generators with high efficiency. Nowadays, modern turbo-generators have efficiencies greater than 98%. Although this amount should not be obtained for all kind of machines, efficiency will remain one of the main parameters for customer choice. Efficiency is also linked to the life of the machine: the higher the efficiency is, the longer the machine's lifetime. During the past decade, new forms of energy production have appeared and generators have been developed to fit well into this market. For example, wind generators evolved towards permanent magnet generators having high polarity and running at low speed. Nevertheless, their structure is not fixed. An industrial company has built a prototype of such a generator which uses fractional-slot concentrated-windings (FSCW). This kind of winding is not the structure used by default in such electrical machines. Another field of interest is in autonomous generators which can be used on boats. Even if everyone has in mind large merchant ships, we must not forget smaller ships, such as fishing boats and short-range cruise ships, which spend the most of their time near the coast. This kind of ship does nothave large areas for installing the electric generation or the electric propulsion. It is the reason why, in this article, we focus on the efficiency of machines using fractional-slot concentrated-windings. In many publications which compare performances between distributed and concentrated windings, the result is almost the same. The efficiency of FSCW is not as high as the efficiency associated to the machines which are using distributed windings. Design methods have to be redrawn to integrate, as soon as possible, the loss mitigation in order to provide the best efficiency in power conversion. The following discussion, step by step, introduces the loss mitigation in every part of a machine using FSCW. To close the discussion, a design is produced and it appears that efficiency can be enhanced with suitable design methods.

Comparison of Drivetrain Topologies for an Ankle Gait Cycle

“…Equations ( 28)- (30) has the same meaning as Equations ( 17)- (19). The subscripts 'ir', 'or' and ' f ' represent the inner rotor branch, the outer rotor branch and the flywheel, respectively.…”

Influence of a Winding Short-Circuit Fault on Demagnetization Risk and Local Magnetic Forces in V-Shaped Interior PMSM with Distributed and Concentrated Winding

“…In this paper, the authors attempted to analyze two similar motors differing in the number of slots per rotor pole and in the stator winding. The first motor used distributed winding (DW) and the second motor used concentrated winding (CW) [26][27][28][29][30]. Because the electromagnetic torque of the IPM motor is developed due to an interaction between the stator winding field and the rotor PM field in the air gap, the transient electromagnetic torque during stator faulty operation should provide interesting results, pointing toward a more stable motor.…”

Design, Analysis of the Location and Materials of Neodymium Magnets on the Torque and Power of In-Wheel External Rotor PMSM for Electric Vehicles

“…Due to high efficiency, torque and generated power, the most common are permanent magnet synchronous motors and BLDC motors. The design and analysis of the BLDC motor properties for operation in the wheel hub have been presented in [21], while synchronous motor design process is presented in [22][23][24][25][26][27][28][29]. An important aspect related to motor design is to obtain as much torque and power as possible from its volume [30], while limiting the cogging torque and torque pulsations [31].…”