This paper introduces a new set of methods to directly integrate ultracapacitor banks into cascaded multilevel inverters used for large vehicle propulsion. The idea is to replace the regular dc-link capacitors with ultracapacitors in order to combine the energy storage unit and motor drive. This approach eliminates the need for an interfacing dc-dc converter and considerably improves the efficiency of regenerative braking energy restoration in electric and hybrid vehicles. Utilizing the proposed modulation control set, the two cascaded inverters can have their dc voltage levels maintained at any ratio (even a non-integer ratio) or dynamically varied over a wide range without disrupting the normal operation of the electric motor. As an advantage, ultracapacitor voltage or state of charge can be freely controlled for braking and/or acceleration power management. An optimal regenerative energy management scheme is proposed based on the vehicle's speed range considerations. Detailed simulations verified the proposed methods.
S. Lu et al., "An Unique Ultracapacitor Direct Integration Scheme in Multilevel Motor Drives for Large Vehicle Propulsion," Conference Record of the 2006 IEEE Industry Applications Conference 41st IAS Annual Meeting, Institute of Electrical and Electronics Engineers (IEEE), Oct 2006.
The definitive version is available at http://dx.doi.org/10.1109/IAS.2006.256879
2006 IEEE Industry Applications Conference 41st IAS Annual Meeting
Electrical and Computer Engineering
Keywords and Phrases
Cascaded Multilevel Inverter; Energy Storage; Hybrid Converter; Hybrid Vehicle; Regenerative Braking; Ultracapacitor; Vehicle Power Management
Article - Conference proceedings
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