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US 12,749,975 B2Granted
Light-load recovery in a multi-level converter
AssigneeMurata Manufacturing Co., Ltd.
InventorGregory Szczeszynski
Life of this patent
Estimating the term…
Abstract
Circuits and methods that solve the light-load problem of a multi-level converter by generating a ripple signal in the control loop of the multi-level converter that causes a large output current ripple during light load conditions. This added current ripple does not change the average output current but does create a temporary positive and negative current that can be used to balance and charge/discharge the fly capacitors of the multi-level converter. An alternative approach is to add extra switching cycles for the fly capacitors when the output ripple current crosses zero.
Claims20
A multi-level converter including:
- an M-level converter cell comprising:
- an input terminal;
- a set of switches series-coupled between a voltage source and a reference voltage, wherein the set of switches has a switching frequency;
- an output terminal coupled to an innermost pair of the set of switches and configured to be coupled to an inductor;
- switch control inputs coupled to the set of switches;
- and
- at least one fly capacitor coupled in series with certain respective switches and in parallel with switches situated in between the respective switches;
- wherein the M-level converter cell is configured to transform an input voltage applied to the input terminal to an output voltage on the output terminal in response to control signals on the switch control inputs;
- a controller coupled to the switch control inputs and configured to couple to the inductor, the controller configured to monitor an output of the M-level converter cell and dynamically generate a set of switch control input values to the M-level converter cell in response to such monitoring;
- and
- a sub-harmonic signal generator coupled to the controller and configured to selectively inject a sub-harmonic signal into a signal path of the controller, wherein the sub-harmonic signal has a frequency about one-half or less than one-half the switching frequency of the set of switches.
8 more elements
A multi-level converter comprising;
- an M-level converter cell comprising:
- an input terminal;
- a set of switches series-coupled between a voltage source and a reference voltage;
- an output terminal coupled to an innermost pair of the set of switches and configured to be coupled to an inductor;
- switch control inputs coupled to the set of switches;
- and
- at least one fly capacitor coupled in series with certain respective switches and in parallel with switches situated in between the respective switches;
- wherein the M-level converter cell is configured to transform an input voltage applied to the input terminal to an output voltage on the output terminal in response to control signals on the switch control inputs;
- a controller coupled to the switch control inputs and configured to couple to the inductor, the controller configured to monitor an output of the M-level converter cell and dynamically generate a set of switch control input values to the M-level converter cell in response to such monitoring;
- and
- a sub-harmonic signal generator coupled to the controller and configured to selectively inject a sub-harmonic signal into a signal path of the controller, wherein the sub-harmonic signal enables charge balancing of the at least one fly capacitor.
8 more elements
A multi-level converter comprising:
- an M-level converter cell comprising:
- an input terminal;
- a set of switches series-coupled between a voltage source and a reference voltage;
- an output terminal coupled to an innermost pair of the set of switches and configured to be coupled to an inductor;
- switch control inputs coupled to the set of switches;
- and
- at least one fly capacitor coupled in series with certain respective switches and in parallel with switches situated in between the respective switches;
- wherein the M-level converter cell is configured to transform an input voltage applied to the input terminal to an output voltage on the output terminal in response to control signals on the switch control inputs;
- a controller coupled to the switch control inputs and configured to couple to the inductor, the controller configured to monitor an output of the M-level converter cell and dynamically generate a set of switch control input values to the M-level converter cell in response to such monitoring;
- and
- a sub-harmonic signal generator coupled to the controller and configured to selectively inject a sub-harmonic signal into a signal path of the controller, wherein the sub-harmonic signal generator is configured to scale the sub-harmonic signal as a function of the absolute value of an average current through the inductor to obtain a scaled sub-harmonic signal and inject the scaled sub-harmonic signal.
8 more elements
Dependencies are inferred from the claim text.