Current ripple sensing controller for a single-stage LED driver
AssigneeQueen's University at Kingston
InventorsYajie Qiu, Yan-Fei Liu
Life of this patent
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Abstract
A current-ripple-based control strategy for an AC-DC converter with a series ripple cancellation converter (RCC). Embodiments provide series ripple cancellation by sensing the load current information, and significantly simplify the control circuitry. In addition, the embodiments allow input voltage of the series RCC to tightly track its output voltage peak value with no extra control circuit, thus minimizing the RCC component voltage stress as well as the RCC loss. Embodiments are suitable for driving an LED load, where they eliminate LED light flicker caused by the power factor correction (PFC) stage, and significantly reduce its output capacitance.
Claims15
A controller for an alternating current-to-direct current (AC-DC) power converter comprising a main power factor correction (PFC) stage, the controller comprising:
- a sensing circuit that senses a power converter load current;
- a main PFC stage control loop that regulates an average load current;
- and
- a current ripple control loop including an AC current ripple sensing block and a compensation network that uses the sensed power converter load current to generate a signal corresponding to a double-line-frequency ripple of the load current, and uses the signal to regulate a series ripple cancellation converter output;
- wherein the series ripple cancellation converter output substantially cancels the double-line-frequency ripple in the load current.
A method for controlling an alternating current-to-direct current (AC-DC) power converter comprising a main power factor correction (PFC) stage, comprising:
- sensing a power converter load current via a sensing circuit;
- using a main PFC stage control loop to regulate an average load current;
- and
- using a current ripple control loop including an AC current ripple sensing block and a compensation network to generate a signal corresponding to a double-line-frequency ripple of the load current, and using the signal to regulate a series ripple cancellation converter output;
- wherein the series ripple cancellation converter output substantially cancels the double-line-frequency load current ripple.
Dependencies are inferred from the claim text.