Biography:

Prof. Kai Yang is a Doctoral Supervisor and the Vice Dean of the School of electrical and electronic engineering at Huazhong University of Science and Technology (HUST). He is a visiting scholar of the KU Leuven in Belgium, a visiting professor of the Changwon National University in South Korea, the Director of the Engineering Center of the Ministry of Education of "New Motors and Special Electromagnetic Equipment", the Executive Deputy Director of the Collaborative Innovation Center of the Ministry of Education of "Strong Electromagnetic", the Head of the National New Energy Technology Business Incubator and Specialized MakerSpace of the Ministry of Science and Technology, the Executive Director of the IEEE PES Electric Vehicle Electric Drive Subcommittee, the Senior Member of IEEE and the Chinese society for electrical engineering, the Vice Chairman of Hubei Electrical Engineering Society and Director of Electrical Machinery Committee, and the Vice Chairman of Hubei New Energy Industry Promotion Association.

He has been committed to the theoretical research and technology research and development of new motor systems in the fields of new energy vehicles, wind power generation, high-end machine tools, and engineering machinery. He has presided over four projects of the National Natural Science Foundation of China, one project of National Key R&D Program of China, two National Science and Technology Major Projects, one National Science and Technology Support Program in China and more than 40 key projects of other provincial ministries and commissions and school-enterprise research projects. He has published more than 200 high-level academic papers as the first author or corresponding author, of which 170 are included in SCI/EI. He has authorized 22 invention patents, 28 utility model patents and six software copyrights.

Speech title: New type of direct-drive permanent magnet motor and its robust control technology


Abstract: Direct-driving permanent magnet machine is the key component of advanced equipment such as construction machinery, power equipment, electric vehicles and intelligent appliances. In the direct drive system, the gear box is no longer required, thus the shaft of the machine is coupled with the load directly. In this case, any torque ripples from the machine will be directly passed to the load. Therefore, for direct drive system, it is vital that the torque quality of the machine be guaranteed.
To reach higher torque density and lower torque ripple, a novel axial-radial flux permanent magnet machine (ARFPMM) and its control system are proposed. T-type SMC core, axial rotor, and radial rotor are applied to support axial-radial flux path and make full use of the space. A dimensionality reduction method is proposed to transform the FEA model from 3D to 2D. The error between the proposed 2D model and the standard 3D model is less than 1%, while the calculation time is reduced more than 90%. A new topology of fractional slot concentrated winding (FSCW) with unbalanced phase belt is proposed, which reduces the harmonic magnetomotive force by 76%. The concentration effect and stratification effect of FSCW is first introduced and the influence on short pitch factor is analyzed. The high frequency harmonic magnetomotive force is reduced by optimizing the width of stator tooth. Asymmetric bidirectional skewing technology is proposed to optimize the cogging torque. The cogging torque is reduced by 86% while the average torque is reduced by 0.3%.
On the other hand, the torque ripple of the machine is also relevant to the harmonic components of the current. Therefore, the control strategy of such kind of machine is also worth researching. To suppress current harmonics of the machine, a novel ADRC controller combining a complex coefficient extended state observer (CCF-ESO) is proposed. CCF-ESO takes advantage of the orthogonality of d-axis current harmonics and q-axis current harmonics to accurately extract AC disturbance. Then, the current loop ADRC controller based on the CCF-ESO is able to achieve a desired AC disturbance rejection performance. Experimental results shows that the proporsed method can reduce the 6th order harmonics of d- and q-axis by 42%.