Exterior view of laboratory in the Engineering Building of INET campus

Interior View of the Laboratory 

National "Twelfth Five-Year" scientific and technological innovation achievement exhibition

Multi-bearing experimental rig

Megawatt-class magnetic bearing high-speed permanent magnet motor

High and low-temperature test chambers

Publications

The Division publishs about 10 academic papers per year.

Research Highlights

1）Engineering Prototype Development for Helium Circulator

The helium circulator stands as a pivotal rotating machinery component necessitating bearings with high availability and reliability. Magnetic bearings constitute a crucial "bottleneck" technology for the helium circulator. The Division conducted in-depth research and development on several core technologies of magnetic bearings tailored to the structure, functionality, and operational requirements of the primary helium circulator for the HTR-PM Demo project. This research encompassed various key technologies, including active vibration suppression control technology for magnetic bearings, complex dynamics of the bearing-rotor system, real-time online monitoring and fault diagnosis technology, on-site electromagnetic compatibility analysis, auxiliary bearing design, and overall system reliability.

By small-scale test and full-scale engineering prototype test, the performance and reliability of the magnetic bearings, the controllers,  the sensors, the power amplifiers, and other critical equipment were comprehensively evaluated.  A thorough understanding of the core technologies of magnetic bearings, spanning from engineering design and manufacturing to testing, debugging, and operational maintenance, was achieved.  This achievement marked a significant breakthrough in domesticating the magnetic bearings for primary helium circulators of HTGRs. The achievement was awarded as one of the "Top Ten Scientific and Technological Advancements in Universities" by the Ministry of Education in 2014.

The Engineering Prototype of Helium Circulator	Nitrogen Experiment Loop for the Engineering Prototype of Primary Helium Circulator
Test Stand for the Engineering Prototype of Primary Helium Circulator

2）Helium Turbine Compressor

In the project HTR-10GT, "High-Temperature Gas-Cooled Reactor Helium Turbine Power Generation System" , the helium turbine compressor operates in a high-temperature sealed environment with helium. The rotor of the turbine unit needs to surpass two flexible critical speeds to achieve the operational speed of 15,000 r/min. Traditional bearings struggle to meet the support requirements of large, heavily loaded, high-speed flexible rotors in the unique environment of the primary loop of a nuclear reactor. Therefore, the utilization of magnetic bearings for support is considered the only feasible solution. To ensure the safe and reliable operation of the helium turbine rotor and its smooth passage through the second-order flexible critical speed, a series of corresponding theoretical and experimental studies need to be conducted extensively.

The Division has brought together talents from various disciplines such as structural design, rotor dynamics analysis, system identification, automatic control, sensors, and power electronics to overcome the challenge of surpassing the second-order critical speed of flexible rotors under controllable conditions. 

3）Automatic Detection Technology for Magnetic Bearing

During the maintenance, both electrical and mechanical characteristics of the magnetic bearings should be detected, i.e. insulation detection and gap detection. Traditional testing methods usually need manual measurement after dismantling which result in errors and cannot meet the high efficiency and precision requirements during on-site test in nuclear power plants. The Division has developed automatic detection technology for magnetic bearings. This technology avoids dismantling and can automatically detect the insulation status of magnetic bearings without affecting the existing main wiring of the bearings. It also enables one-click, multi-channel rapid gap detection without additional sensors, with an error accuracy controlled within 5%. This technology has been applied to HTR-PM Demo project.

YANG Guojun

yanggj@mail.tsinghua.edu.cn

(Last Updated: 2024-05)