Optimal trajectory control for LLC resonant converter for soft start-up
AssigneeVirginia Tech Intellectual Properties, Inc.
InventorsWeiyi Feng, Fred C. Lee
Life of this patent
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Abstract
By setting switching instants of a switching circuit of a resonant power converter based on current in a resonant circuit reaching a current limit of a current limitation band, soft start-up of the power converter can be achieved to avoid or limit electrical stress with full control over a trade-off between time required to settle to a full load steady-state mode of operation and the amount of electrical stress permitted while soft start up switching frequency is automatically optimized.
Claims20
A method of operating a switching resonant power converter comprising steps of setting a current limitation band, monitoring resonant inductor current, controlling switching times of switches of said switching resonant power converter during start-up to occur at times when monitored inductor current equals limits of said current limitation band thereby establishing a variable switching frequency until bias on a resonant capacitor reaches a steady state voltage, and allowing the power converter to assume a steady state mode of frequency regulation mode operation in accordance with build-up of output voltage.
A resonant power converter including a resonant circuit, a switching circuit to connect a power source to said resonant circuit, a current monitoring circuit to monitor current in said resonant circuit, and a control circuit for establishing switching times of said switching circuit to be at times when said current in said resonant circuit coincides with upper and lower current limits of a current limitation band thereby establishing a variable switching frequency during start-up and transitioning to frequency regulation mode control during steady-state operation.
Dependencies are inferred from the claim text.