The dynamic operation requirement for grid flexibility provision (e.g., load shifting and frequency regulation) can cause accelerated aging of electric motors. For example, the left plot of the figure below shows aggressive demand response control could result in motor aging rates 60% faster than aging-conscious control strategies. Through a DOE grant, the team is currently working to characterize motor aging behaviors under different operating conditions and develop an aging-aware control solution to mitigate the lifetime impact of dynamic motor operations. The goal will be achieved through (1) conducting laboratory tests to gather empirical evidence on impacts of flexibility provision on the lifetime of electric motors; (2) developing a calibrated numerical model to characterize motor aging behavior and estimate the lifetime impact under dynamic operating conditions; and (3) synthesizing an aging-aware control strategy that strikes an optimal balance between the aging effect and financial gain for flexibility provision. A multi-factor motor aging model will be developed by combining transient electromagnetic simulations and winding insulation degradation models that capture thermal, electrical, and mechanical stresses of insulation materials.


Fig. Left – Compressor life consumption rates with conventional load shifting and aging-aware load shifting control strategies. Right – Weighted harmonic factor method to characterize temperature rise and thermal aging rate of motor winding insulation.


  • Sanchez, J., Jiang, Z. and Cai, J., Modeling and Mitigating Lifetime Impact of Demand Responsive Control of HVAC Systems, Journal of Building Performance Simulation, 2022, preprint. DOI: 10.1080/19401493.2022.2094466.
  • Cai, J., Zhang, H. and Jin, X., Aging-Aware Predictive Control of PV-Battery Assets in Buildings, Applied Energy, 2018, preprint. DOI: 10.1016/j.apenergy.2018.12.003.