Patent ID: 11936291
Assignee: PSEMI CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of setting output level and charge-balancing a set of fly capacitors during a switching cycle of a multi-level converter circuit that includes (1) a set of switches configured to be serially coupled between a first terminal and a second terminal, and (2) the set of fly capacitors each fly capacitor being coupled between a pair of low-side switches among the set of switches and between a pair of high-side switches among the set of switches, the method including:
(a) selecting one fly capacitor among the set of fly capacitors that has not previously been selected;
(b) if a voltage on the selected fly capacitor is above an associated target voltage and there are remaining low-side or high-side switches among the set of switches that are currently closable to enable a discharge path for the selected fly capacitor, then (1) setting the remaining low-side or high-side switches that enable the discharge path for the selected fly capacitor to a closed state, and otherwise (2) setting the remaining low-side or high-side switches that enable a charging path for the selected fly capacitor to a closed state;
(c) looping to step (a) until all fly capacitors among the set of fly capacitors have been selected; and
(d) for a remaining pair of left-over switches among the set of switches, setting an associated high-side switch or an associated low-side switch among the set of switches to a closed state based on a set of switch count rules, wherein the multi-level converter circuit has M total levels and the set of switch count rules for a level m of the multi-level converter circuit includes:
(a) M−m low-side switches among the set of switches must be closed;
(b) m−1 high-side switches among the set of switches must be closed; and
(c) low-side switches and high-side switches among the set of switches that are not required to be closed must be open.