Rockwell Automation Technologies Incorporated

Kai Tian

Zhongyuan Cheng

Bin Wu

David Dewei Xu

Navid RezA Zargari

Methods and charging apparatus are presented for charging cell capacitors of a multilevel power conversion system, in which an auxiliary charging source is selectively applied across DC bus terminals while one or more selected multilevel converter cells are alternately switched between a first state to bypass the selected cell or cells and a second state to charge the cell capacitor or capacitors of the selected cell via charging current from the auxiliary charging source.

Modular multilevel converter and charging circuit therefor

Multilevel converters and space vector modulation operating methods are presented in which fewer than all possible switching states are employed for space vector modulation of rectifier and inverter circuits to promote common mode voltage contribution cancellation or reduction therebetween and by using subsets of possible space vector modulation switching states associated with minimal positive or negative common mode voltages and in some cases using virtual vectors which have zero common mode voltages to eliminate the 3rd order harmonic components in common mode voltage as well as to reduce common mode voltage affects associated with multilevel inverter stages.

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Toronto, Canada

Kai Tian