Liyan Qu

Liyan Qu

Contact Information:

City Campus (Lincoln)
SEC C290J
(402) 472-3771
lqu2@unl.edu

Associate Professor

Academic Degrees

  • Ph.D., Electrical Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 2007
  • M.S., Electrical Engineering, Zhejiang University, Hangzhou, China, 2002
  • B.S., Electrical Engineering, Zhejiang University, Hangzhou, China, 1999

Areas of Research and Professional Interest

  • Modeling techniques to facilitate the analysis and design of complex, high-performance electric energy systems
  • Numerical analysis and computer aided design for electric machinery and power electronic devices and circuits
  • Electric machines and drives
  • Magnetic devices and materials
  • Power management for electric energy systems, e.g., battery-powered systems
  • Renewable energy systems, e.g., wind, solar
  • Wireless power transmission
  • Energy harvesting

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Courses Taught

Selected Publications

Refereer Journal Papers:
  1. C. Jia, J. Cui, W. Qiao, and L. Qu, “Real-time model predictive control for battery-supercapacitor hybrid energy storage systems using linear parameter varying models,” IEEE Journal of Emerging and Selected Topics in Power Electronics, accepted for publication.
  2. Y. Peng, W. Qiao, and L. Qu, “Compressive sensing-based missing-data-tolerant fault detection for remote condition monitoring of wind turbines,” IEEE Transactions on Industrial Electronics, vol. 69, no. 2, pp. 1937-1947, Feb. 2022.
  3. F. Chen, W. Qiao, H. Wang, and L. Qu, “A simple zero-sequence voltage injection method for carrier-based pulse-width modulation of the three-level NPC inverter,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 9, no. 4, pp. 4687-4699, Aug. 2021.
  4. Z. Wang, W. Qiao, and L. Qu, “A real-time adaptive IGBT thermal model based on an effective heat propagation path concept,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 9, no. 4, pp. 3936-3946, Aug. 2021.
  5. J. Cui, L. Qu, and W. Qiao, "Electromagnetic transformer with a continuously and quickly adjustable voltage ratio," IEEE Transactions on Industry Applications, vol. 57, no. 3, pp. 2421-2430, May-June 2021.
  6. Y. Peng, F. Cheng, W. Qiao, and L. Qu, “Wind turbine drivetrain gearbox fault diagnosis using information fusion on vibration and current signals,” IEEE Transactions on Instrumentation and Measurement, vol. 70, Art no. 3518011, May 2021.
  7. L. Qu, W. Qiao, and L. Qu, “An extended-state-observer-based sliding-mode speed control for permanent-magnet synchronous motors,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 9, no. 2, pp. 1605-1613, Apr. 2021.
  8. L. Qu, W. Qiao, and L. Qu, “Active-disturbance-rejection-based sliding-mode current control for permanent-magnet synchronous motors,” IEEE Transactions on Power Electronics, vol. 36, no. 1, pp. 751-760, Jan. 2021.
  9. L. Qu, W. Qiao, and L. Qu, “An enhanced linear active disturbance rejection rotor position sensorless control for permanent magnet synchronous motors,” IEEE Transactions on Power Electronics, vol. 35, no. 6, pp. 6175-6184, Jun. 2020.
  10. T. Kim, W. Qiao, and L. Qu, “An enhanced hybrid battery model,” IEEE Transactions on Energy Conversion, vol. 34, no. 4, pp. 1848-1858, Dec. 2019.
  11. F. Cheng, L. Qu, W. Qiao, C. Wei, and L. Hao, “Fault diagnosis of wind turbine gearboxes based on DFIG stator current envelope analysis,” IEEE Transactions on Sustainable Energy, vol. 10, no. 3, pp. 1044-1053, Jul. 2019.
  12. F. Cheng, L. Qu, W. Qiao, and L. Hao, “Enhanced particle filtering for remaining useful life prediction of a wind turbine drivetrain gearbox,” IEEE Transactions on Industrial Electronics, vol. 66, no. 6, pp. 4738-4748, Jun. 2019.
  13. J. Wang, W. Qiao, and L. Qu, “Wind turbine bearing fault diagnosis based on sparse representation of condition monitoring signals,” IEEE Transactions on Industry Applications, vol. 55, no. 2, pp 1844-1852, Mar.-Apr. 2019.
  14. J. C. do Prado, W. Qiao, L. Qu, and J. R. Agüero, “The next-generation retail electricity market in the context of distributed energy resources: Vision and integrating framework,” Energies, vol. 12, no. 3, 491, Feb. 2019.
  15. X. Jin, F. Cheng, Y. Peng, W. Qiao, and L. Qu, “Drivetrain gearbox fault diagnosis:  Vibration- and current-based approaches,” IEEE Industry Applications Magazine, vol. 24, no. 6, pp. 56-66, Nov.-Dec. 2018.
  16. W. Qiao and L. Qu, “Prognostic condition monitoring for wind turbine drivetrains via generator current analysis,” Chinese Journal of Electrical Engineering, vol. 4, no. 3, pp. 80-89, Sept. 2018.
  17. J. Wang, F. Cheng, W. Qiao, and L. Qu, “Multiscale filtering reconstruction for wind turbine gearbox fault diagnosis under varying-speed and noisy conditions,” IEEE Transactions on Industrial Electronics, vol. 65, no. 5, pp 4268-4278, May 2018.
  18. Y. Peng, W. Qiao, L. Qu, and J. Wang, “Sensor fault detection and isolation for a wireless sensor network-based remote wind turbine condition monitoring system,” IEEE Transactions on Industry Applications, vol. 54, no. 2, pp 1072-1079, Mar.-Apr. 2018.
  19. F. Cheng, J. Wang, L. Qu, and W. Qiao, “Rotor-current-based fault diagnosis for DFIG wind turbine drivetrain gearboxes using frequency analysis and a deep classifier,” IEEE Transactions on Industry Applications, vol. 54, no. 2, pp 1062-1071, Mar.-Apr. 2018.
  20. F. Cheng, L. Qu, and W. Qiao, “Fault prognosis and remaining useful life prediction of wind turbine drivetrain gearboxes using current signal analysis,” IEEE Transactions on Sustainable Energy, vol. 9, no. 1, pp 157-167, Jan. 2018.
  21. F. Cheng, Y. Peng, L. Qu, and W. Qiao, “Current-based fault detection and identification for wind turbine drivetrain gearboxes,” IEEE Transactions on Industry Applications, vol. 53, no. 2, pp. 878-887, Mar.-Apr. 2017.
  22. H. Wang, L. Qu, W. Qiao, and B. Liu, “Magnetic flux valve: A magnetoelectric materials-based device for conversion and control of electric power,” IEEE Transactions on Industrial Electronics, vol. 64, no. 3, pp. 2451-2458, Mar. 2017.
  23. C. Wei, Z. Zhang, W. Qiao, and L. Qu, “An adaptive network-based reinforcement learning method for MPPT control of PMSG wind energy conversion systems,” IEEE Transactions on Power Electronics, vol. 31, no. 11, pp. 7837-7848, Nov. 2016.
  24. Z. Zhang, C. Wei, W. Qiao, and L. Qu, “Adaptive saturation controller-based direct torque control for permanent-magnet synchronous machines,” IEEE Transactions on Power Electronics, vol. 31, no. 10, pp. 7112-7122, Oct. 2016.
  25. X. Bai, W. Qiao, and L. Qu, “Robust AC optimal power flow for power networks with wind power generation,” IEEE Transactions on Power Systems, vol. 31, no. 5, pp. 4163-4164, Sept. 2016.
  26. X. Jin, W. Qiao, Y. Peng, F. Cheng, and L. Qu, “Quantitative evaluation of wind turbine faults under variable operational conditions,” IEEE Transactions on Industry Applications, vol. 52, no. 3, pp. 2061-2069, May/Jun. 2016.
  27. Z. Wang, B. Tian, W. Qiao, and L. Qu, “Real-time aging monitoring for IGBT modules using case temperature,” IEEE Transactions on Industrial Electronics, vol. 68, no. 2, pp. 1168-1178, Feb. 2016.
  28. H. Wang, L. Qu, and W. Qiao, “Adjustable-voltage-ratio magnetoelectric transformer,” IEEE Magnetics Letters, vol. 6, Article# 6000104, Sept. 2015.
  29. C. Ma and L. Qu, “Multiobjective optimization of switched reluctance motors based on design of experiments and particle swarm optimization,” IEEE Transactions on Energy Conversion, vol. 30, no. 3, pp. 1144-1153, Sept. 2015.
  30. C. Wei, Z. Zhang, W. Qiao, and L. Qu, “Reinforcement learning-based intelligent maximum power point tracking control for wind energy conversion systems,” IEEE Transactions on Industrial Electronics, vol. 62, no. 10, pp. 6360-6370, Oct. 2015.
  31. Z. Zhang, Y. Zhao, W. Qiao, and L. Qu, “A discrete-time direct-torque control for direct-drive PMSG-based wind energy conversion systems,” IEEE Transactions on Industry Applications, vol. 51, no. 4, pp. 3504-3514, July-Aug. 2015.
  32. J. Zeng, W. Qiao, and L. Qu, “An isolated three-phase bidirectional DC-DC converter for photovoltaic systems with energy storage,” IEEE Transactions on Industry Applications, vol. 51, no. 4, pp. 3493-3503, July-Aug. 2015.
  33. J. Zeng, W. Qiao, and L. Qu, “LCL-resonant single-switch isolated DC-DC converter,” IET Power Electronics, vol. 8, no. 7, pp. 1209-1216, July 2015.
  34. Z. Zhang, Y. Zhao, W. Qiao, and L. Qu, “A space-vector modulated sensorless direct-torque control for direct-drive PMSG wind turbines,” IEEE Transactions on Industry Applications, vol. 50, no. 4, pp. 2331-2341, Jul./Aug. 2014.
  35. J. Zeng, W. Qiao, L. Qu, and Y. Jiao, “An isolated multiport DC-DC converter for simultaneous power management of multiple different renewable energy sources,” IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 2, no. 1, pp. 70-78, Mar. 2014.
  36. T. Kim, W. Qiao, and L. Qu, “Power electronics-enabled self-X multicell batteries:  A design toward smart batteries,” IEEE Transactions on Power Electronics, vol. 27, no. 11, pp. 4723-4733, Nov. 2012.
  37. L. Qu and W. Qiao, “Constant power control of DFIG wind turbines with supercapacitor energy storage,” IEEE Transactions on Industry Applications, vol. 47, no. 1, pp 359-367, Jan.-Feb. 2011.
  38. W. Qiao, L. Qu, and R. G. Harley, “Control of IPM synchronous generator for maximum wind power generation considering magnetic saturation,” IEEE Transactions on Industry Applications, vol. 45, no. 3, pp. 1095-1105, May-June 2009.
  39. L. Qu and P. L. Chapman, “Extraction of low-order nonlinear inductor models from a high-order physics-based representation,” IEEE Transactions on Power Electronics, vol. 21, no.3, pp. 813-817, May 2006.
  40. L. Qu, J. Wu, and Y. Chen, “Automatic generation and fast implementation of finite element mesh,” Electric Machines and Control, vol. 6, no.1, pp. 34-38, Mar. 2002.
  41. L. Qu, J. Wu, and Y. Chen, “Object-oriented visualization CAD system for DC motor,” Small & Special Electrical Machines, vol. 28, no. 6, pp. 40-42, 2000.