We design power electronics equipped with advanced control and diagnostics tools, for power conversion and energy storage systems. We are experienced in electrochemical impedance spectroscopy and wireless power transfer systems. Although our research has focused on batteries, the same technology is applicable to other electrical energy storage systems such as supercapacitors and fuel cells. Our research finds also applications in biomedical engineering. We practice almost all aspects of power electronics including:

  • Circuit design,
  • Modeling,
  • Simulation,
  • Design of control and condition monitoring systems,
  • Practical implementation, and evaluation.

Electrochemical Impedance Spectroscopy

Electrochemical impedance spectroscopy (EIS) has been a powerful tool for characterization, parameterization, and measurement of ohmic resistance, double layer capacitance, polarization, charge transfer, and diffusion processes in electrochemical and biomedical systems. State-of-charge (SOC) and state-of-health (SOH) of energy storage systems such as batteries, fuel cells, and super-capacitors, are estimated by using EIS. Known as electrical impedance tomography (EIT) in medicine, EIS is a proven technique for medical imaging, neural engineering, medical tissues characterization, and cancer detection.

We study and design EIS circuits, control systems and data analytics. We design multipurpose robust controllable EIS devices, which control the process of excitation signal despite circuit and batteries’ uncertainties using quantitative feedback theory (QFT) and H-infinity. Our EIS devices are capable of running offline and online tests, during charge and discharge for energy storage systems monitoring and diagnostics. Our EIS devices provide the user with an option to apply and study various types of excitation signals based on advanced system identification theories. We developed various system identification and Bayesian inference algorithms for the analysis and modeling of EIS data in both frequency and time domains. We worked on the identification of both fractional and ordinary Randles circuit models, which are widely used in the study of EIS data. 

Wireless Power Transfer Systems

Because of easy adaptation, galvanic isolation, portability, and high reliability in harsh environments, wireless or inductive power transfer (WPT or IPT) system is gaining popularity, and has been a promising technology for various applications in transportation electrification, electric appliances, robotics, and biomedical engineering.

We work on modeling and control of WPT systems. In a recent work, we developed a method for transfer function modeling of WPT systems. We develop robust control techniques, which guarantee satisfactory operations of WPT systems around the desired resonant frequency in the presence of uncertainties. We worked on two-degree-of-freedom and proportional-integral (PI) robust control of WPT systems by using quantitative feedback theory (QFT), fixed -structured H-infinity, and Skogestad Internal Model Control (SIMC) methods.  

The video demonstrates the effectiveness of the proposed QFT-based robust control technique on an experimental WPT system that we built in the lab. The experimental WPT system includes a full-bridge inverter, full-bridge rectifier, series-series capacitor-based compensation circuits, and uncertain DC loads. 

Selected Publications

  • M Abareshi, E Sadeghi, M Saif, M Hamzeh, SMM Alavi, “Multi-Purpose Controllable Electrochemical Impedance Spectroscopy Using Synchronous Buck Converter,” Journal of Energy Storage, 2022 (In Press). 
  • R Naghash, SMM Alavi, E Afjei, “Robust Control of Wireless Power Transfer Despite Load and Data Communications Uncertainties,” IEEE Journal of Emerging and Selected Topics in Power Electronics, 9(4), pp. 4897-4905, 2021.
  • E Sadeghi, MH Zand, M Hamzeh, M Saif, SMM Alavi, “Controllable Electrochemical Impedance Spectroscopy: From Circuit Design to Control and Data Analysis,” IEEE Transactions on Power Electronics, 35(9), pp. 9935-9944, 2020. 
  • SMM Alavi, S Fekriasl, SN Niyakan, M Saif, “Fault detection and isolation in battery power electronics and chargers,” Journal of Energy Storage, 25, 100807, 2019.
  • SMM Alavi, M Saif, B Shafai, “Accurate state estimation in DC-DC converters using a Proportional-Integral Observer (PIO),” IEEE 23rd International Symposium on Industrial Electronics (ISIE), pp. 1304-1309, 2014.