Integrated design of high‐speed permanent‐magnet machines considering sensorless operation

Abstract

Sensorless operation can significantly improve the reliability of the high-speed permanent-magnet (HSPM) machines. Thus, from the point of view of the whole system, it is necessary to consider sensorless control at the design stage for the HSPM brushless DC machines. In this paper, an integrated design is presented for sensorless control using the third-harmonic back-Electromagnetive force (EMF). Finite element (FE) method is used to integrally design the machine considering electromagnetism, temperature, and rotor structure strength, and the optimum rotor and stator structures are determined to obtain sufficient third-harmonic back-EMF for sensorless control. Simultaneously, the temperature distribution and rotor structure strength are predicted by the FE method. Finally, a prototype is fabricated and the experimental system is built to verify the machine structure, design method, and sensorless control strategy.The machine structure is shown in Fig. 1. The design of HSPM machines involves continuous iterations of electromagnetic properties, temperature, and rotor structure strength. Meanwhile, the sensorless control using third-harmonic back-EMF is considered during the integrated design process. The flowchart of integrated design for HSPM machines is shown in Fig. 2. The aim of integrated design is to gain balance of all properties of HSPM machines. Machine Topologies Considering Third-Harmonic for Sensorless OperationThe amplitude of the third-harmonic back-EMF is important to realize sensorless control of a high-speed machine, and the amplitude of fundamental back-EMF should meet the requirement of the designed machine. The fundamental equations related to back-EMF are developed in this section.

Influence of the Electromagnetic Characteristics in Air Region on High‐Speed Permanent Magnet Generator Based on Multi‐Physical Field

“…Only the fundamental electromagnetic field of the generator is calculated, the flux density (B r ) in the out surface of permanent magnets is considered as the sinusoidal distribution, as shown in (2):…”

“…In recent years, high-speed permanent magnet generators (HSPMG) have been widely used in aerospace, distributed power generation and gas turbines, because of its advantages of high efficiency, high power density and dynamic response capability [1][2][3]. In order to increase the power density, the generator is designed with the higher electromagnetic load and smaller size [4][5][6].…”

Design Factors of High- speed Turbo-electric Distributed Propulsion System

“…The application of TeDP power generation requires low weight and high-speed operation. The PM machines have low weight and are typically designed to operate in high-speed conditions, which makes them the most suitable option for application in TeDP [17,25,30,31].…”

A Position Sensorless Control of an Axial Flux-Switching Permanent-Magnet Motor Based on High-Frequency Pulsating Voltage Vector Injection

“…A high-performance transmission system needs to install a position sensor to measure the real-time rotor position, but at the same time, the speed control system has high cost, large size, and low reliability, which limits its application range. In order to overcome the defects caused by mechanical position sensors, scholars have carried out a lot of research on the position sensorless technologies of AC motors [5][6][7][8][9][10][11][12][13][14][15][16]. Sensorless technology reduces the size and cost of the motor, and improves the reliability of the system.…”

“…Sensorless technology reduces the size and cost of the motor, and improves the reliability of the system. These technologies can be divided into two categories, namely based on the back EMF [5][6][7] and the based on salient pole effect [8][9][10][11][12][13][14][15]. The method based on the back EMF has superior performance at medium and high speeds, but since the magnitude of the back EMF is proportional to the rotation speed, it is not suitable for zero-speed and low-speed operation.…”