@article{won_jalali_liang_zhang_srdic_lukic_2019, title={Auxiliary Power Supply for Medium-Voltage Power Converters: Topology and Control}, volume={55}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2019.2915511}, abstractNote={This paper presents an isolated auxiliary power supply for medium-voltage power electronics systems. The proposed converter comprises two stages: a non-isolated ac/dc stage that connects directly to the medium-voltage line, and an isolated dc/dc stage that provides 100-W output power at 24 V, with 10 kV isolation. The proposed modular ac/dc stage uses just one active semiconductor device per module, features an internal capacitor voltage balancing, and achieves power factor correction by employing predictive current control. High switching frequency operation of both converter stages enable a reduction in system size and weight when compared to traditional low-frequency transformer-based approach. The proposed converter is simulated and its operation is validated experimentally on a 100-W prototype.}, number={4}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Won, Jehyuk and Jalali, Gholamreza and Liang, Xinyu and Zhang, Chi and Srdic, Srdjan and Lukic, Srdjan M.}, year={2019}, pages={4145–4156} }
 @inproceedings{won_jalali_liang_zhang_srdic_lukic_2018, title={Auxiliary power supply for medium-voltage power electronics systems}, DOI={10.1109/apec.2018.8341005}, abstractNote={This paper presents an auxiliary power supply for medium-voltage (MV) power electronics systems, based on modular multilevel series-parallel converter (MMSPC). The converter connects to 2.4 kV RMS at the input, and produces 24 V dc at the output, providing 100 W of power with 10 kV isolation. Unlike the traditional solutions which use a grid-frequency bulky and heavy potential transformers, the proposed converter can operate at higher switching frequencies, thus reducing the weight and providing higher power density, compared to the traditional approach. Additionally, the proposed converter features an internal capacitor voltage balancing and achieves power factor correction (PFC) by using predictive control. The proposed converter is simulated and its operation is experimentally validated on the developed prototype at low input voltage.}, booktitle={Thirty-third annual ieee applied power electronics conference and exposition (apec 2018)}, author={Won, J. and Jalali, G. and Liang, X. Y. and Zhang, C. and Srdic, S. and Lukic, S.}, year={2018}, pages={173–179} }
 @inproceedings{mobarrez_fregosi_jalali_bhattacharya_bahmani_2017, title={A novel control method for preventing the PV and load fluctuations in a DC microgrid from transferring to the AC power grid}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85028632617&partnerID=MN8TOARS}, DOI={10.1109/icdcm.2017.8001069}, abstractNote={DC microgrids are gaining popularity due to the higher efficiency, reliability, lower costs and better compatibility with DC loads compared to their AC counterparts. Large-scale deployment of distributed renewable energy resources like solar in the microgrids, has to provide utilities and grid operators the capability to safely and reliably mitigate the impact of solar and loads intermittency on the main AC power grid. In this paper, a novel control method is proposed to prevent solar and load variations inside a DC microgrid from transferring to the AC power grid while the microgrid is operating in grid-tied mode. The control method works based on having multiple slack terminals with different voltage controller response times in parallel. The response times can be adjusted such that the battery converters of the microgrid absorb solar and load fluctuations while the grid-tied inverters contribute to their voltage regulation's shares smoothly according to their droop parameters. This method improves upon previously discussed methods in literature in that it does not require single slack terminal, DC bus signaling or converter mode changes.}, booktitle={2017 IEEE 2nd International Conference on Direct Current Microgrids, ICDCM 2017}, author={Mobarrez, M. and Fregosi, D. and Jalali, G. and Bhattacharya, Subhashish and Bahmani, M.A.}, year={2017}, pages={352–359} }
 @inproceedings{jalali_ahmed_kim_pan_2016, title={Instability detection and protection scheme for efficiency optimized V/f driven synchronous reluctance motors (SynRM).}, DOI={10.1109/ecce.2016.7855206}, abstractNote={This paper introduces a new method to stabilize synchronous reluctance motors (SynRMs) driven by efficiency optimized V/f control utilizing optimized flux. Efficiency optimized V/f driven SynRMs are prone to instabilities. Specifically, it becomes unstable for either fast ramp acceleration or large load disturbances. For example, in an efficiency optimized V/f control scheme, flux is reduced under low load to improve efficiency. However, a large load increase would lead to loss of synchronisation under this condition. In this paper, a stability analysis of efficiency optimized V/f driven SynRM is performed. Instability threshold indicators using power factor and stator current angle are proposed. A novel instability protection scheme is introduced and verified in experiment.}, booktitle={2016 ieee energy conversion congress and exposition (ecce)}, author={Jalali, G. and Ahmed, S. and Kim, H. and Pan, Z.}, year={2016} }