Click the following title to learn more about the notice
Team Introduction
Cheng Ming, Ph.D., chief professor and doctoral supervisor of Southeast University, IEEE fellow, Iet fellow. At present, he is the director of the wind power research center of Southeast University, the director of the Institute of advanced electrical machinery and power electronic integrated system of Southeast University, the member of the academic committee of Southeast University, and the director of Jiangsu new energy vehicle electrical machinery and drive system engineering laboratory.
Over the past 30 years, he has presided over and undertaken more than 60 projects of NSFC, national 973 program and national 863 program, published more than 400 papers (more than 220 papers included in SCI); edited micro and special motors and systems, renewable energy power generation technology textbooks, published stator permanent magnet brushless motor? Theory, design and control, and new drive of electric vehicles According to the invitation of Springer publishing house, he participated in the compilation of Encyclopedia of sustainability science and technology, and at the invitation of Wiley publishing house, he participated in the compilation of Encyclopedia of automotive engineering and acted as the third volume editor; he was authorized with more than 130 Chinese invention patents, 3 PCT patents and 1 European patent.
It has won the second prize of national technological invention, the first prize of natural science of the Ministry of education, the first prize of science and technology of Jiangsu Province, the first prize of science and technology of China's machinery industry, and other academic awards. It has also won the "333 high-level talent training project" of Jiangsu Province, including young and middle-aged science and technology leaders, outstanding scientific and technological workers, academic leaders of "six talent peaks", ten outstanding patent inventors of Jiangsu Province, and Zhongda University And Jiangsu patent inventor award and other honorary titles. Employed as IEEE IAS distinguished lecturer in 2015 / 2016; enjoying the government special contribution allowance of the State Council.
Wen Honghui, Ph.D. candidate, focuses on the analysis, design and optimization of the field modulated motor. He has participated in major international (regional) cooperative research projects of NSFC and key basic research projects of the 973 Program of the Ministry of science and technology. Now he has participated in major projects of NSFC, published 5 SCI and EI papers and applied for 5 national invention patents. He has won the first prize of excellent graduation design of this college in Jiangsu Province in 2017 and IEEE IAS Myron Zucker in 2017 The second prize of undergraduate student design competition, the third best student of Jiangsu Province in 2019.
Jiangsu electric machinery and power electronics Alliance (jempel) is founded by IEEE Led by Fellow and Cheng Ming, the chief professor of Southeast University, with 12 full-time teachers in the school of electrical engineering of Southeast University as the core, a number of Yangtze River scholars, thousands of experts as the support, and more than 100 postdoctoral and doctoral and master degree students as the backbone of the research team Application.
Based on the "theory of motor field modulation", this paper defines the synchronous and Asynchronous Modulation behavior and the components of synchronous torque and asynchronous torque of the generalized field modulation motor, compares and analyzes the key differences and illustrates them with examples, and expounds the dialectical relationship between synchronous / Asynchronous Modulation and synchronous / asynchronous torque components.
Based on the above theoretical analysis and definition, this paper studies the possible operation mode, existing conditions and torque components of the BDFM, summarizes the similarities and differences between the BDFM and the electrically excited synchronous motor under the single fed synchronous mode, analyzes the topological structure of the composite rotor of the multi-layer magnetic barrier and the short-circuit coil, and qualitatively describes the auxiliary short-circuit coil in the field modulation behavior In addition, the modulation behavior and torque characteristics of the simple salient pole type field modulation motor are described.
DOI: 10.19595/j.cnki.1000-6753.tces.190255
Research background
In recent years, the new topology motor based on the principle of magnetic field modulation can use the additional effective harmonic magnetic field to improve the average torque, so its main electromagnetic torque may contain multiple torque components. Taking a simple salient pole type of field modulation motor as an example, although the motor mainly uses asynchronous modulation behavior, it can generate synchronous torque component, and the relationship between modulation behavior and torque component is complex and difficult to understand; on the other hand, the modulation behavior and torque characteristics of this type of motor are interlinked, so it can be summarized and described uniformly.
The rotor of BDFM, including short-circuit coil, simple salient pole, multilayer magnetic barrier (radial and axial) and other rotor structures, is an important member of the field modulation motor. Its essence is a new type of composite motor with two AC electrical ports and one common mechanical port. Due to the unique composite characteristics of the BDFM, the two AC electrical ports can operate in a variety of modes when they are powered in different ways, corresponding to different operation modes and rotor structures, the electromagnetic torque components of the BDFM may be different, and the relationship between the modulation behavior and the torque components is more complex. Therefore, it is necessary to define and analyze the magnetic field modulation behavior and torque components, and summarize the dialectical relationship between them, so as to provide a new way to analyze the modulation behavior and electromagnetic characteristics of GMM motor.
According to the unified theory of air gap magnetic field modulation, the basic motor unit can be standardized as a cascade of "excitation source modulator filter". According to the relative state of the initial excitation source and the modulator, the modulation behavior can be defined as synchronous modulation and asynchronous modulation. If there is relative motion between the modulator and the excitation source, it is asynchronous modulation; if the two remain relatively static, it is synchronous modulation.
The common asynchronous modulation behavior includes the Asynchronous Modulation behavior of the salient pole rotor of the reverse flux permanent magnet motor, as shown in Fig. 1A; the common synchronous modulation behavior includes the synchronous modulation behavior of the salient pole rotor of the embedded permanent magnet synchronous motor, and the modulation structure is shown in Fig. 1b.
Figure 1 common modulation behavior of magnetic field
The definition of synchronous and asynchronous torque components only depends on the source of magnetic field and the state of motor speed. If the generating mechanism of a torque component is shown in Figure 2a, which is established by the same magnetic field source, and the rotor moves relative to the magnetic field source, that is, the rotor speed is not equal to the synchronous speed of the magnetic field, then the torque is asynchronous torque; if a torque component is established by the same magnetic field response of the polar logarithm of two independent sources, and the rotor speed is equal to the equivalent synchronous speed of the two magnetic field sources, then the The torque is the synchronous torque, as shown in Figure 2B.
Fig. 2 mechanism diagram of synchronous torque and asynchronous torque
The characteristics of torque components are related to the modulation behavior, which refers to the main modulation behavior that can change the amplitude and spatial spectrum distribution of the initial magnetomotive force. The specific analysis is as follows:
(1) Synchronous modulation generates synchronous torque component. Taking the embedded permanent magnet synchronous motor shown in Fig. 1b as an example, it includes two independent magnetic field sources: permanent magnet excitation field and stator armature field; the stator salient polarity can be ignored, so it is unit modulation; the initial excitation source and salient rotor remain relatively static, and their modulation behavior is synchronous modulation; the two sets of magnetic field poles have the same logarithm and remain relatively static, and the rotor speed is constant Because of the synchronous speed of the rotating magnetic field established by the sub armature winding, the embedded permanent magnet synchronous motor only contains one synchronous torque component.
(2) Asynchronous Modulation generates synchronous torque component. Taking the flux reverse permanent magnet motor shown in Figure 1A as an example, the synchronous modulation behavior of the stator salient only changes the harmonic amplitude of the static permanent magnet excitation field without affecting its spectrum distribution; on the other hand, because the pole pairs of the excitation and the armature field are not equal, the rotor is required to operate at the equivalent synchronous speed of the two fields, so that the modulated excitation field and the modulated armature field can interact with each other To produce the average electromagnetic torque. Obviously, the rotor salient pair of flux reversal permanent magnet motor is asynchronous modulation, and the main electromagnetic torque meets the definition of synchronous torque, so asynchronous modulation can generate synchronous torque component.
(3) Asynchronous Modulation generates asynchronous torque component. Referring to Fig. 2B, taking the traditional squirrel cage induction motor as an example, it only contains one stator magnetic field source, and its main electromagnetic torque is generated by the interaction between the stator fundamental rotating magnetic field BF and the rotor fundamental magnetic field B ′ f established by the rotor current induced by the magnetic field, whose essence is established by the same magnetic field source; the logarithm of BF and B ′ f poles is the same, and regardless of the actual rotor speed, B ′ f is the same In space, the rotating speed relative to the stator is always equal to the synchronous speed of BF, so the two can react with each other to produce average torque; at the moment, the rotor moves relative to the magnetic field established by the stator winding, that is, the synchronous speed of the rotor speed and the rotating magnetic field of the stator is not equal, which is asynchronous operation (modulation), so the squirrel cage induction motor only contains an asynchronous torque component.
Because of its unique composite characteristics, it can run in a variety of different modes, such as simple asynchronous mode, cascade asynchronous mode, single fed synchronous mode, double fed synchronous mode and so on. Under the single fed synchronous mode, the bldcf induction motor and the electric excitation synchronous motor have certain similarities, which are mainly reflected in:
(1) The magnetic field structure is the same: two electrical ports are one set of DC power supply excitation, one set of AC power supply provides armature magnetic field.
(2) The mode of magnetic adjustment is similar: in this mode, the brushless doubly fed induction motor can apply excitation and adjust the power factor, such as the electric excitation synchronous motor, and its adjustable amount is only the current amplitude, so generally it can only adjust the reactive power.
(3) The main component of synchronous torque is: two sets of independent magnetic field sources are used to generate the torque of the bldcf induction motor and the electric excitation synchronous motor, and the rotor speed operates at the equivalent synchronous speed, meeting the conditions for generating the synchronous torque. On the other hand, when the PW and CW terminal voltages of the BDFM are given, the stator winding resistance and the leakage inductance are ignored, and the rotor leakage impedance is inversely proportional to the torque peak value, and the ratio of the rotor leakage impedance to the rotor resistance affects the proportion between the asynchronous torque component and the synchronous torque component. The larger the ratio is, the closer the rotor leakage impedance angle is to π / 2, and the smaller the proportion of asynchronous component is. In the limit case, when the rotor resistance is zero, the asynchronous torque component will not appear in the torque expression, only the synchronous torque component is included.
There are also differences between the brushless doubly fed induction motor and the electrically excited synchronous motor
(1) The brushless doubly fed induction motor can realize the brushless: the brushless doubly fed induction motor realizes the brushless through the modulation mode, the rotor operates at the sub natural synchronous speed under the single fed synchronous mode, and can establish the single frequency relationship between PW and CW. If the BDFM operates at PW synchronous speed or CW synchronous speed, it can not be started normally, which can also prove that the BDFM is a field modulation motor dominated by Asynchronous Modulation behavior, and there is essential difference between its working principle and that of synchronous motor.
(2) The modulation behavior is different: the rotor modulator of the electric excitation synchronous motor is relatively static with the excitation source, which is synchronous modulation, while the brushless doubly fed induction motor is asynchronous modulation.
(3) The components of torque components are different: the electric excitation synchronous motor contains only one synchronous torque component, not asynchronous torque component; while the brushless doubly fed induction motor contains two synchronous torque and asynchronous torque components respectively.
A composite rotor with multilayer magnetic barrier and short-circuit coil is formed by adding magnetic barrier layer in the core of radial laminated rotor and auxiliary short-circuit coil in the magnetic barrier rotor