@article{mackey_rachi_peng_husain_2020, title={Optimization and Control of a Z-Source, Ultrafast Mechanically Switched, High-Efficiency DC Circuit Breaker}, volume={56}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2020.2970657}, abstractNote={A novel design of the Z-source circuit breaker topology is presented to minimize on-state losses of the protection device. An ultrafast mechanical switch is proposed to commutate the fault current and improve the controllability of the circuit breaker. Replacing the power thyristor in the Z-source circuit breaker and integrating an advanced control scheme reduces energy losses with a low-resistance mechanical contactor. The proposed design facilitates bidirectional current flow, enhances control capability for distributed energy resources, and improves ride-through capabilities during load transients. Z-source circuit breakers utilize an impedance network to create a forced current zero crossing in the event of a fault, allowing the inline thyristor to isolate the fault from the source through reverse bias. However, full load current flows through the thyristor, resulting in high loss and heat generation. The concept is validated, and a proper control scheme is developed for this circuit breaker through an analytical estimation model of the system dynamics during a fault. Simulation and modeling are performed in power systems computer aided design (PSCAD) and piecewise linear electrical circuit simulation (PLECS). Finally, an experimental laboratory prototype is tested to validate the analytical and simulation models and certify the control logic.}, number={3}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Mackey, Landon and Rachi, Md Rifat Kaisar and Peng, Chang and Husain, Iqbal}, year={2020}, pages={2871–2879} }
 @article{peng_mackey_husain_huang_yu_lequesne_briggs_2017, title={Active Damping of Ultrafast Mechanical Switches for Hybrid AC and DC Circuit Breakers}, volume={53}, ISSN={["1939-9367"]}, DOI={10.1109/tia.2017.2740830}, abstractNote={An active damping method for Thomson coil actuated ultrafast mechanical switches is proposed, including its control. Ultrafast mechanical switches are crucial for both dc and ac circuit breakers that require fast-acting current-limiting capabilities. However, fast motion means high velocity at the end of travel resulting in over-travel, bounce, fatigue, and other undesirable effects. The active damping proposed in this paper not only avoids such issues but actually enables faster travel by removing limitations that would otherwise be necessary. This active damping mechanism is applicable in particular to medium- and high-voltage circuit breakers, but can be extended to actuators in general. A 15 kV/630 A/1 ms mechanical switch designed to enable the fast protection of medium voltage dc circuits is used as a testbed for the concept. The switch is based on the principle of repulsion forces (Thomson coil actuator). By energizing a second coil, higher opening speeds can be damped, resulting in limited over-travel range of the movable contact. The overall structure is simple and the size of the overall switch is minimized. To validate the concept and to study the timing control for best active damping performance, both finite element modeling and experimental studies have been carried out.}, number={6}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Peng, Chang and Mackey, Landon and Husain, Iqbal and Huang, Alex Q. and Yu, Wensong and Lequesne, Bruno and Briggs, Roger}, year={2017}, pages={5354–5364} }
 @inproceedings{pritchard_mackey_zhu_gregory_norris_2017, title={Modular electric generator rapid deployment DC microgrid}, DOI={10.1109/icdcm.2017.8001030}, abstractNote={The development of a rapidly deployable modular electric generator based on plug-in hybrid vehicle DC architectures provides a highly reliable DC microgrid for use in applications with unstable infrastructure or highly sensitive loads. The result is the commercial production of early stage prototype units built by Schneider Electric with onboard energy storage, combustion generator and rapid interconnects for loads, renewable energy and grid connection.}, booktitle={2017 IEEE Second International Conference on DC Microgrids (ICDCM)}, author={Pritchard, E. and Mackey, L. and Zhu, D. and Gregory, D. and Norris, G.}, year={2017}, pages={106–110} }
 @inproceedings{mackey_rachi_peng_husain_2017, title={Optimization of a Z-source, ultra-fast mechanically switched, high efficiency DC circuit breaker}, DOI={10.1109/ecce.2017.8096665}, abstractNote={A novel modification of the Z-source circuit breaker topology is presented for low voltage applications. An ultra-fast mechanical switch has been used in place of the solid-state switch (thyristor) in the Z-source circuit breaker to reduce the energy loss utilizing the very low resistance of mechanical contactors. The proposed modification also facilitates bi-directional current flow for distributed energy resource integration and improves ride through capabilities during downstream load transients. Existing Z-source circuit breaker designs utilize an impedance network to create a forced zero current crossing in the event of a fault in commutating thyristor to isolate the fault from source. However, all load current must flow through the thyristor during normal operation resulting in high loss due to on-state voltage drop of the solid-state switch. To validate the concept and develop proper control for this circuit breaker, both simulations and experimental studies have been carried out. The proposed breaker has been modelled in PSCAD for analysis. Additionally, an analytical estimation model of the system dynamics during fault has been developed to validate the simulations. A test circuit rated for 400 V and 20 A has been designed, constructed and tested.}, booktitle={2017 ieee energy conversion congress and exposition (ecce)}, author={Mackey, L. and Rachi, M. R. K. and Peng, C. and Husain, I.}, year={2017}, pages={3764–3770} }
 @inproceedings{mackey_rachi_peng_husain_2017, title={Z-source circuit breaker utilizing ultra-fast mechanical switch for high efficiency DC circuit protection}, DOI={10.1109/icdcm.2017.8001084}, abstractNote={A novel modification to Z-Source DC circuit breakers has been proposed to reduce power consumption from its predecessor significantly. The power thyristor serves as the means of circuit isolation and voltage blocking in the event of a fault in traditional Z-Source DC circuit breakers. However, Z-Source circuit breakers direct full load current through the Thyristor. The resulting voltage difference and current flow yield substantial power consumption, heat generation, and reduced efficiency. Integrating a fast-mechanical switch and associated control, a zero current crossing and circuit isolation is achieved without significant on-state switch losses.}, booktitle={2017 IEEE Second International Conference on DC Microgrids (ICDCM)}, author={Mackey, L. and Rachi, M. R. K. and Peng, C. and Husain, I.}, year={2017}, pages={452–458} }
 @inproceedings{peng_mackey_husain_huang_lequesne_briggs_2016, title={Active damping of ultra-fast mechanical switches for hybrid AC and DC circuit breakers}, DOI={10.1109/ecce.2016.7854816}, abstractNote={An active damping method for Thomson coil actuated ultra-fast mechanical switches is proposed, including its control. Ultra fast mechanical switches are crucial for both DC and AC circuit breakers that require fast-acting, current-limiting capabilities. However, fast motion means high velocity at the end of travel, resulting in over-travel, bounce, fatigue, and other undesirable effects. The active damping proposed in this paper not only avoids such issues, but actually enables faster travel by removing limitations that would otherwise be necessary. This active damping mechanism is applicable in particular to medium and high voltage circuit breakers, but can be extended to actuators in general. A 15kV/630A/1ms mechanical switch, designed to enable the fast protection of medium voltage DC circuits, is used as a testbed for the concept. It is based on the principle of repulsion forces (Thomson coil actuator). By energizing a second coil, higher opening speeds can be damped with limited over-travel range of the movable contact. The overall structure is simple, and the size of the overall switch is minimized. To validate the concept and to study the timing control for best active damping performance, both finite element modeling and experimental studies have been carried out.}, booktitle={2016 ieee energy conversion congress and exposition (ecce)}, author={Peng, C. and Mackey, L. and Husain, I. and Huang, A. and Lequesne, B. and Briggs, R.}, year={2016} }