Flying capacitor voltage and inductor current compensation for nonlinear coupling in a three-level converter
A system may include a power inductor electrically coupled to the plurality of switches, and a flying capacitor coupled to the plurality of switches, wherein the plurality of switches are controllable among a plurality of switch configurations in order to generate an output voltage from an input voltage received by the multi-level power converter. The system may also include a flying capacitor voltage control loop configured to, based on an error signal between a measurement of a flying capacitor voltage across terminals of the flying capacitor and a flying capacitor reference voltage, generate switch control signals for switching among the plurality of switch configurations in order to regulate the flying capacitor voltage and a compensator configured to apply compensation to the flying capacitor reference voltage based on a measurement of the input voltage.
1 . A system comprising:
a multi-level power converter comprising a plurality of switches, a power inductor electrically coupled to the plurality of switches, and a flying capacitor coupled to the plurality of switches, wherein the plurality of switches are controllable among a plurality of switch configurations in order to generate an output voltage from an input voltage received by the multi-level power converter;
a flying capacitor voltage control loop configured t, based on an error signal between a measurement of a flying capacitor voltage across terminals of the flying capacitor and a flying capacitor reference voltage, generate switch control signals for switching among the plurality of switch configurations in order to regulate the flying capacitor voltage;
a power inductor current control loop configured to, based on a second error signal between a measurement of an inductor current flowing through the power inductor and a reference inductor current, generate switch control signals for switching among the plurality of switch configurations in order to regulate the inductor current; and
a compensator configured to:
apply compensation to the flying capacitor reference voltage based on a measurement of the input voltage; and
apply compensation to the power inductor current control loop based on a measurement of the flying capacitor.
2 . The system of claim 1 , wherein the compensation depends on a windowed average of the input voltage.
3 . The system of claim 2 , wherein a measurement window for the windowed average is based on one or more of the switch control signals.
4 . The system of claim 2 , wherein a measurement window for the windowed average is based on a switching frequency of the multi-level power converter.
5 . A method comprising, in a multi-level power converter comprising a plurality of switches, a power inductor electrically coupled to the plurality of switches, and a flying capacitor coupled to the plurality of switches, wherein the plurality of switches are controllable among a plurality of switch configurations in order to generate an output voltage from an input voltage received by the multi-level power converter:
based on an error signal between a measurement of a flying capacitor voltage across terminals of the flying capacitor and a flying capacitor reference voltage, generating switch control signals for switching among the plurality of switch configurations in order to regulate the flying capacitor voltage;
based on a second error signal between a measurement of an inductor current flowing through the power inductor and a reference inductor current, generating switch control signals for switching among the plurality of switch configurations in order to regulate the inductor current; and
applying compensation;
to the flying capacitor reference voltage based on a measurement of the input voltage; and
to a power inductor current control loop based on a measurement of the flying capacitor.
6 . The method of claim 5 , wherein the compensation depends on a windowed average of the input voltage.
7 . The method of claim 6 , wherein a measurement window for the windowed average is based on one or more of the switch control signals.
8 . The method of claim 6 , wherein a measurement window for the windowed average is based on a switching frequency of the multi-level power converter.