@article{hong_bai_lukic_2014, title={Closed-Form Expressions for Minimizing Total Harmonic Distortion in Three-Phase Multilevel Converters}, volume={29}, ISSN={["1941-0107"]}, DOI={10.1109/tpel.2013.2290377}, abstractNote={The total harmonic distortion (THD) of a waveform is a standard way to quantify its deviation from a sinusoid. In three-phase systems, we are interested in minimizing 3THD: the component of THD produced by odd nontriplen harmonics. However, its definition involves an infinite sum, making it difficult to evaluate and analyze. This paper solves the problem of finding equivalent closed-form expressions for the 3THD of a staircase waveform. In particular, two expressions are rigorously derived, which reveal 3THD to be a piecewise differentiable function. One expression is shorter but describes the pieces implicitly. The other is longer but describes the pieces explicitly. We minimize 3THD using the closed-form expression and provide a comparison with previous techniques. Finally, we provide experimental results that show close agreement with the theoretical results.}, number={10}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, author={Hong, David and Bai, Sanzhong and Lukic, Srdjan M.}, year={2014}, month={Oct}, pages={5229–5241} }
 @inproceedings{bai_lukic_2014, title={Modular design of cascaded H-bridge for community energy storage systems by using secondary traction batteries}, DOI={10.1109/apec.2014.6803779}, abstractNote={This paper proposed a Community Energy Storage System (CES) by using reclaimed tractions batteries. The cascaded H-Bridge topology is selected for this application after reviewing all possible solutions. Control strategies to have independent control of each H-Bridge are reviewed and existing control strategies are all centralized control. To have modular design and independent control of each module, a new control strategy is proposed for cascaded H-Bridge converter. With this control strategy, each H-Bridge module will have its own controller and there is no connection between the controllers. All the control strategies are implemented in the local controllers and no central controller is needed. A small scale CES system is built to verify the proposed control strategy with great success.}, booktitle={2014 twenty-ninth annual ieee applied power electronics conference and exposition (apec)}, author={Bai, S. Z. and Lukic, S.}, year={2014}, pages={3297–3304} }
 @article{bai_lukic_2013, title={New Method to Achieve AC Harmonic Elimination and Energy Storage Integration for 12-Pulse Diode Rectifiers}, volume={60}, ISSN={["1557-9948"]}, DOI={10.1109/tie.2012.2196903}, abstractNote={The 12-pulse rectifier is often used to supply high-power industrial loads. Its ability to effectively and cheaply mitigate the harmonics on the ac side has ensured its dominance in the industry even as active front ends become cheaper and more reliable. Despite its many benefits, the 12-pulse rectifier is not able to reduce the ac-side harmonics to a level acceptable by the pertinent IEEE standards without additional filtering. In this paper, we outline a novel method to profile the rectifier output current to be triangular which results in low ac-side harmonics. The novelty in the proposed approach is that we exploit the dc-side filter design to minimize the volt-amperes (VA) rating of the current source used to profile the dc-side rectifier current. Additional benefits of the proposed method include lower VA rating of the dc filter, simple integration of dc energy storage, and effective ac harmonic control even when the initial rectifier current is discontinuous.}, number={7}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Bai, Sanzhong and Lukic, Srdjan M.}, year={2013}, month={Jul}, pages={2547–2554} }
 @article{bai_lukic_2013, title={Unified Active Filter and Energy Storage System for an MW Electric Vehicle Charging Station}, volume={28}, ISSN={["1941-0107"]}, DOI={10.1109/tpel.2013.2245146}, abstractNote={A network of fast-charging stations is of great importance for widespread adoption of electric vehicles (EV) if the so-called range anxiety issue is to be resolved. As with petrol stations, we expect that multiple chargers will be co-located to form charging stations. This layout allows for the fast-charging station to make use of a common rectifier stage and several dc/dc stages to charge multiple EVs. This paper builds on our previous work where we proposed a novel dc-side filter for the 12-pulse rectifier and investigated the power profile for a MW fast-charging station. In this paper, we propose a novel control approach for the filter, based on the virtual resistor injection, which results in further reduction in dc ripple, ac-side harmonics, and filter VA ratings. We also demonstrate that, with the proposed topology and control, the filter stage can be used as dc-side energy storage system.}, number={12}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, author={Bai, Sanzhong and Lukic, Srdjan M.}, year={2013}, month={Dec}, pages={5793–5803} }
 @inproceedings{bai_lukic_2012, title={A 12-pulse diode rectifier with energy storage integration and high power quality on both AC and DC side}, DOI={10.1109/ecce.2012.6342274}, abstractNote={The 12-pulse diode rectifier has been widely used in high power applications. Although the dominant 5th and 7th harmonics of the input current are canceled out, the total harmonic distortion is still well above 5%. Therefore additional filtering is required to meet the pertinent standards. In this paper, several methods that deal with the input current harmonics are reviewed. The fundamentals behind these methods are discussed. By utilizing the concept of virtual resistor, a new approach is proposed in this paper to, not only eliminate the AC input current harmonics, but also eliminate DC output voltage harmonics. Moreover, the energy storage integration is possible with the proposed method. We analyze the control and operation of the proposed method. Simulation and experiment results verify the analysis.}, booktitle={2012 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Bai, S. Z. and Lukic, S.}, year={2012}, pages={4042–4048} }
 @inproceedings{lomaskin_bai_lukic_2012, title={Current sharing control for cascaded h-bridge applied to secondary use batteries in community energy storage systems}, DOI={10.1109/ecce.2012.6342455}, abstractNote={This paper presents a cascaded H-bridge inverter topology for the application of secondary-use batteries as grid-connected energy storage. The proposed control strategy allows a degree of control over individual battery currents while the total system follows an arbitrary current command. This enables the aggregation and optimal use of battery packs with different capacities and states of health, overcoming a significant drawback of existing implementations.}, booktitle={2012 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Lomaskin, M. and Bai, S. Z. and Lukic, S.}, year={2012}, pages={2107–2111} }
 @inproceedings{pantic_bai_lukic_2011, title={A new tri-state-boost-based pickup topology for inductive power transfer}, DOI={10.1109/ecce.2011.6064241}, abstractNote={In this paper we present a new circuit design for multi-pickup high-power inductive power transfer systems. The proposed design combines parallel compensated resonant tank with tri-state boost converter. By synchronizing tri-state boost switching period with the half-period of resonant tank voltage, we position the inherently discontinuous current pulse drawn by tri-state boost to control both active and reactive power flow from the resonant circuit to tri-state boost. Controllable reactive current can be used effectively to emulate appropriate inductance or capacitance to tune the resonant tank and achieve optimal power transfer.}, booktitle={2011 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Pantic, Z. and Bai, S. Z. and Lukic, S.}, year={2011}, pages={3495–3502} }
 @article{pantic_bai_lukic_2011, title={ZCS LCC-Compensated Resonant Inverter for Inductive-Power-Transfer Application}, volume={58}, ISSN={["1557-9948"]}, DOI={10.1109/tie.2010.2081954}, abstractNote={Inductive power transfer (IPT) is commonly used to transmit power from an extended loop (track) to a number of galvanically isolated movable pick-ups. To maximize the power transfer and minimize converter requirements, various compensation circuits have been proposed for both the track (primary) and the pick-up (secondary). This paper investigates the suitability of the LCC series-parallel compensation for IPT primary design. A new compensation-circuit design procedure is proposed that considers high-order current harmonics and results in inverter zero-current switching. The proposed compensation is compared with the classical compensation designed for zero phase angle between the inverter voltage and current fundamental components. Expressions for the bifurcation boundary, voltampere rating of reactive-compensation elements, and the current at the moment of switching are derived and analyzed. Analytical results are verified both via PSpice simulations and experimentally using a 1-hp MOSFET-based prototype.}, number={8}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, publisher={IEEE}, author={Pantic, Zeljko and Bai, Sanzhong and Lukic, Srdjan M.}, year={2011}, month={Aug}, pages={3500–3510} }
 @inproceedings{bai_pantic_lukic_2010, title={A comparison study of control strategies for ZVS resonant converters}, DOI={10.1109/iecon.2010.5675019}, abstractNote={This paper studies three fundamental switching patterns for resonant converters to achieve Zero Voltage Switching (ZVS) operation. To evaluate the performance of the three control methods, three resonant topologies are taken into consideration: series resonant, parallel resonant and seriesparallel resonant. The criteria functions for ZVS operation are derived for each control method and topology. The results show that the Asymmetrical Clamped Mode control (ACM) can guarantee lower switching frequency than other two control methods while keeping ZVS operation. Moreover, the circulating power for each control method is analyzed. The relationships between the switching frequency and the maximum power transfer of the three resonant topologies are derived and the series-parallel resonant topology shows a superior characteristic. Experiment results are given to verify some of the results.}, booktitle={Iecon 2010: 36th annual conference of the ieee industrial electronics society}, author={Bai, S. Z. and Pantic, Z. and Lukic, S.}, year={2010} }
 @article{du_zhou_bai_lukic_huang_2010, title={Review of Non-isolated Bi-directional DC-DC Converters for Plug-in Hybrid Electric Vehicle Charge Station Application at Municipal Parking Decks}, ISSN={["1048-2334"]}, DOI={10.1109/apec.2010.5433359}, abstractNote={There is a growing interest on plug-in hybrid electric vehicles (PHEV's) due to energy security and green house gas emission issues, as well as the low electricity fuel cost. As battery capacity and all-electric range of PHEV's are improved, and potentially some PHEV's or EV's need fast charging, there is increased demand to build high power off-board charging infrastructures. A charge station architecture for municipal parking decks has been proposed, which has a DC microgrid to interface with multiple DC-DC chargers, distributed renewable power generations and energy storage, and provides functionalities of normal and rapid charging, grid support such as reactive and real power injection (including V2G), current harmonic filtering and load balance. Several non-isolated bidirectional DC-DC converters suited for charge station applications have been reviewed and compared, as the major focus of this paper. Half bridge converter is a good candidate but it is difficult to maintain high efficiency in wide battery pack voltage range. A variable frequency pulse width modulation (VFPWM) scheme is proposed to mitigate this issue. Finally three-level bi-directional DC-DC converter is suggested to be employed in this application. A 10kW prototype verifies that 95.1–97.9% full load efficiency can be achieved in charging mode with 180–360V battery pack voltage. In addition, the inductor size is only one third of the half bridge counterpart, which is a great advantage for high power converters.}, journal={2010 TWENTY-FIFTH ANNUAL IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION (APEC)}, author={Du, Yu and Zhou, Xiaohu and Bai, Sanzhong and Lukic, Srdjan and Huang, Alex}, year={2010}, pages={1145–1151} }
 @inproceedings{pantic_bai_lukic_2009, title={Inductively coupled power transfer for continuously powered electric vehicles}, booktitle={2009 ieee vehicle power and propulsion conference, vols 1-3}, author={Pantic, Z. and Bai, S. and Lukic, S. M.}, year={2009}, pages={1097–1104} }