Bridgeless boost power factor correction circuit for constant current input
First Claim
1. A bridgeless 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 first switching device coupled to the input capacitor and the current source, wherein the first switching device is operable during a first half cycle of the input current and shorted during a second half cycle of the input current, and wherein when operable, the first switching device switches between an ON state and an OFF state;
a second switching device coupled to the input capacitor and the current source, wherein the second switching device is operable during the second half cycle of the input current and shorted during the first half cycle of the input current, and wherein when operable, the second switching device switches between the ON state and the OFF state;
a controller coupled to the first switching device and the second switching device, wherein the controller switches the first or second switching device between the ON state and the OFF state, depending on which half cycle the input current is in, wherein when one of the first or second switching devices is in the OFF state, the input capacitor charges and the input voltage rises, and when one of the first or second switching devices is in the ON state, the input capacitor drains and the input voltage drops; 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 in phase with the input current.
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Accused Products
Abstract
The present disclosure provides techniques for power factor correction on a constant current system without the use of a diode rectifier bridge. In an example embodiment, the present disclosure provides a power factor correction circuit which includes two switching MOSFETs biased in opposite directions which operate during opposite half cycles of the input current. The power factor correction circuit generates an input voltage to match the phase of the input current. The input voltage is generated via charging and draining of an input capacitor by the MOSFETs. The MOSFETs are driven on a duty cycle synchronously associated with the input current wave form.
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Citations
20 Claims
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1. A bridgeless 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 first switching device coupled to the input capacitor and the current source, wherein the first switching device is operable during a first half cycle of the input current and shorted during a second half cycle of the input current, and wherein when operable, the first switching device switches between an ON state and an OFF state; a second switching device coupled to the input capacitor and the current source, wherein the second switching device is operable during the second half cycle of the input current and shorted during the first half cycle of the input current, and wherein when operable, the second switching device switches between the ON state and the OFF state; a controller coupled to the first switching device and the second switching device, wherein the controller switches the first or second switching device between the ON state and the OFF state, depending on which half cycle the input current is in, wherein when one of the first or second switching devices is in the OFF state, the input capacitor charges and the input voltage rises, and when one of the first or second switching devices is in the ON state, the input capacitor drains and the input voltage drops; 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 in phase with the input current. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A bridgeless 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 a current waveform; a first MOSFET switchable between an ON state and an OFF state when the input current is in a first half cycle; a second MOSFET switchable between the ON state and the OFF state when the input current is in a second half cycle, wherein when one of the first or second MOSFETs is in the OFF state, the input capacitor is charged from the input current and the input voltage rises, and when one of the first or second MOSFETs is in the ON state, the input capacitor is drained and the input voltage drops, wherein switching back and forth between the OFF state and the ON state gives the input voltage a substantially sinusoidal waveform, wherein the sinusoidal waveform is in phase with the input current waveform; and a controller coupled to the first and second MOSFETs, wherein the controller controls switching of the first and second MOSFETs. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. 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; determining if the input voltage reaches a reference voltage; when the input current is in a first half cycle, switching a first switching device from a first state to a second state when the input voltage reaches the reference voltage; when the input current is in a second half cycle, switching a second 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 first and second switching devices. - View Dependent Claims (17, 18, 19, 20)
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Specification