Active power factor correction circuit for a constant current power converter
First Claim
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1. A constant current power factor correction circuit, comprising:
- an input capacitor configured to receive an input current from a constant current source and produce an input voltage;
a rectifier bridge configured to receive the input current and full-wave rectify the input current;
a controller, wherein the controller senses the input current and the input voltage and continuously monitors the input voltage and compares the input voltage to a reference voltage;
a switching device coupled to the controller, wherein the switching device is switchable between a first state and an second state, wherein when the switching device is in the first state, the input capacitor is charged from the input current and the input voltage rises, and when the switching device is in the second state, the input capacitor is drained and the input voltage drops, wherein the controller switches the switching device from the first state to the second state when the input voltage reaches the reference voltage; and
a DC output bus providing an output voltage, wherein the output voltage is a conditioned form of the input voltage, wherein the input voltage is shaped to be in phase with the input current from the constant current source.
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Abstract
The present disclosure provides techniques for power factor correction on a constant current system. In an example embodiment, the present disclosure provides a power factor correction circuit which receives a constant current power input. The power factor correction circuit provides an input voltage tuned to match the phase of the input current. The input voltage is tuned via charging and draining an input capacitor by a switching device. The switching device is driven on a duty cycle synchronously associated with the input current waveform.
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Citations
17 Claims
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1. A constant current power factor correction circuit, comprising:
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an input capacitor configured to receive an input current from a constant current source and produce an input voltage; a rectifier bridge configured to receive the input current and full-wave rectify the input current; a controller, wherein the controller senses the input current and the input voltage and continuously monitors the input voltage and compares the input voltage to a reference voltage; a switching device coupled to the controller, wherein the switching device is switchable between a first state and an second state, wherein when the switching device is in the first state, the input capacitor is charged from the input current and the input voltage rises, and when the switching device is in the second state, the input capacitor is drained and the input voltage drops, wherein the controller switches the switching device from the first state to the second state when the input voltage reaches the reference voltage; and a DC output bus providing an output voltage, wherein the output voltage is a conditioned form of the input voltage, wherein the input voltage is shaped to be in phase with the input current from the constant current source. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A constant current power factor correction circuit, comprising:
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an input capacitor configured to receive an input current from a constant current source and produce an input voltage, wherein the input current comprises an input current waveform; a switching device switchable between a first state and an second state, wherein when the switching device is in the first state, the input capacitor is charged from the input current and the input voltage rises, and when the switching device is in the second state, the input capacitor is drained and the input voltage drops, wherein switching back and forth between the first state and the second state gives the input voltage a substantially sinusoidal waveform, wherein the sinusoidal waveform matches the input current waveform; and a controller coupled to the switching device, wherein the controller controls switching of the switching device, wherein the controller monitors the input voltage and compares the input voltage to a reference voltage, and wherein the controller switches the switching device from the first position to the second position when the input voltage reaches the reference voltage. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of power factor correction on a constant current system, comprising:
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receiving an input current from a constant current input source, the input current having a current waveform; allowing an input capacitor to charge from the input current, wherein an input voltage formed at the input capacitor rises as the input capacitor charges; monitoring, by a controller, the input voltage and determining if the input voltage reaches a reference voltage; switching, by the controller, a switching device from a first state to a second state when the input voltage reaches the reference voltage; allowing the input capacitor to drain, wherein the input voltage drops as the input capacitor drains; and shaping the input voltage to have a voltage waveform similar to the current waveform by controlling the switching of the switching device. - View Dependent Claims (14, 15, 16, 17)
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Specification