Research Areas
Control theory and its applications to mechatronics, robotics, and energy systems
Control Theory
· Robust Control
· Adaptive Control
· Neural Networks
· Boundary Control of Systems Modeled by PDEs
· Real-time Optimization with Extremum Seeking
Sample Publications:
- Y. Wang, B. Ren, Q. Zhong, and J. Dai. Bounded Integral Controller with Limited Control Power for Nonlinear Multiple-Input and Multiple-Output Systems. IEEE Transactions on Control Systems Technology, vol. 29, no. 3, pp. 1348-1355, 2021.
- J. Dai, and B. Ren. UDE-based Robust Boundary Control for an Unstable Parabolic PDE with Unknown Input Disturbance. Automatica, vol. 50, no. 1, pp. 11403-11408. 2018.
- B. Ren, Q. Zhong, and J. Dai. Asymptotic Reference Tracking and Disturbance Rejection of UDE-Based Robust Control. IEEE Transactions on Industrial Electronics, vol. 64, no. 4, pp. 3166-3176. 2017.
- G. Konstantopoulos, Q. Zhong, B. Ren, and M. Krstic. Bounded Integral Control of Input-to-State Practically Stable Non-linear Systems to Guarantee Closed-loop Stability. IEEE Transactions on Automatic Control, vol. 61, no. 12, pp.4196-4202, 2016.
- B. Ren, S. S. Ge, K. P. Tee, and T. H. Lee. Adaptive Neural Control for Output Feedback Nonlinear Systems Using a Barrier Lyapunov Function. IEEE Transactions on Neural Networks. vol. 21, no.8, pp. 1339-1345. 2010.
TTU 108-Converter Smart Grid
Key Features:
· Consisting of 108 physical reconfigurable, reprogrammable converters (SYNDEM Smart Grid Research and Education Kit)
· Organized in 12 microgrids and a substation
· Reconfigurable at the device level and the systems level
· Reprogrammable and open-source
· Auto-code generation
· Suitable for validation of algorithms at all levels, such as control of power electronic converters, integration of distributed energy resources, coordination and operation of multiple power electronic converters, grid management, communication and cybersecurity
Field Testing of Virtual Synchronous Machines (VSM) Grid-forming Technology
Key Features:
· Black-start
· Grid-forming
· Voltage and frequency regulation
· Synchronization
· Islanding detection
· Grid recovery detection
· Seamless transfer between the grid-connected mode and islanded mode
Residential-Scale Microgrid
Research Activities:
· Disaster relief
· Community resiliency enhancement
· Microgrid design with 12 kW solar panels, 3 kW wind turbine, and SYNDEM converters
· Back to back grid converter for system-backup
Sample Publication:
Q.-C. Zhong, Y. Wang, and B. Ren. Connecting the Home Grid to the Public Grid: Field Demonstration of Virtual Synchronous Machines. IEEE Power Electronics Magazine, vol. 6, no. 4, pp. 41 – 49, 2019.
Microgrid Control
Research Activities:
· Autonomous operation in grid-connected or islanded mode
· Load sharing among parallel operation of inverters
· Stable operation and disturbance rejection
· Regulation of voltage and frequency
· Lab-scale microgrid platform with 8 nodes, including wind, solar, battery, generator, utility grid interface, and flexiable loads
Sample Publications:
- Y. Dong, B. Ren, and Q. Zhong. Bounded Universal Droop Control to Enable the Operation of Power Inverters Under Some Abnormal Conditions and Maintain Voltage and Frequency Within Predetermined Ranges. IEEE Transactions on Industrial Electronics, vol. 69, no. 11, pp. 11633-11643, 2022.
- Y. Wang, B. Ren, and Q.-C. Zhong. Robust Power Flow Control of Grid-Connected Inverters. IEEE Transactions on Industrial Electronics, vol. 63, no. 11, pp. 6887-6897, 2016.
Wind Energy & Grid Integration
Research Activities:
· Generator control in wind turbine
· Power flow control in weak grid
· Wind farm optimization with wake effects
· Integration of renewables with utility grid
Sample Publication:
B. Ren, Y. Wang, and Q.-C. Zhong. UDE-based Control of Variable-speed Wind Turbine Systems. International Journal of Control. vol. 90, no. 1, pp. 137-152, 2017.
Solar Energy & Grid Integration
Research Activities:
· Smart PV inverter technology
· Applications of PV + energy storage
Sample Publications:
- Y. Wang, B. Ren, and S. Liyanage. Unified Control Scheme for a Dual-stage Grid-Connected PV System with Mode Change. Solar Energy, vol. 239, pp. 88-101, 2022.
- Y. Wang, and B. Ren. Fault Ride-Through Enhancement for Grid-tied PV Systems with Robust Control. IEEE Transactions on Industrial Electronics, vol. 65, no. 3, pp. 2302-2312, 2018.
Unmanned Aerial Vehicles (UAVs)
Research Activities:
· Robust control/Geometric control
· Critical infrastructure health monitoring (e.g., wind turbine, oil/gas pipeline)
· Control of micro-UAVs in vortex flow
· Autonomous shipboard landing and take-off
· Formation control of swarm UAVs
Sample Publications:
- Y. Wang, Q. Lu, and B. Ren. Wind Turbine Crack Inspection using a Quadrotor with Image Motion Blur Avoided. IEEE Robotics and Automation Letters, vol. 8, no. 2, pp. 1069-1076, 2023.
- Q. Lu, B. Ren, and S. Parameswaran. Uncertainty and Disturbance Estimator-Based Global Trajectory Tracking Control for a Quadrotor. IEEE/ASME Transactions on Mechatronics, vol. 25, no. 3, pp. 1519-1530, 2020.
- B. Ren, S. S. Ge, C. Chen, C.-H. Fua and T. H. Lee. Modeling, Control and Coordination of Helicopter Systems. Springer, 2012.
MEMS
Research Activities:
· Precise motion control in piezoelectric stage with hysteresis compensation
· Hysteresis modeling and continuous control of functional oxide films (VO2)
Sample Publications:
- J. Dai, C. Annasiwatta, A. Bernussi, Z. Fan, J. M. Berg, and B. Ren. Continuous Phase Control of Vanadium Dioxide Films. ASME Journal of Dynamic Systems, Measurement and Control, vol. 142, no. 9, pp. 094503, 2020.
- B. Ren, J. Dai, and Q.-C. Zhong. UDE-based Robust Output Feedback Control with Applications to a Piezoelectric Stage. IEEE Transactions on Industrial Electronics, vol. 67, no. 9, pp. 7819 – 7828, 2020.
Marine / Offshore Systems
Research Activities:
· Station keeping and vibration control of mooring systems
· Offshore wind energy harvesting
Manufacturing
Research Activities:
· Laser pulse shaping and optimization
· Stage positioning control in motion systems
Sample Publication:
B. Ren, P. Frihauf, R. J. Rafac, and M. Krstic. Laser pulse shaping via extremum seeking. Control Engineering Practice. vol. 20, no. 7, pp. 674-683. 2012.