System and method for power factor correction

1. A power factor correction (PFC) system comprising:

a first rectifier diode electrically connected between a first input terminal where an alternating current (AC) power is received and a first output terminal where a direct current (DC) power is output, the first rectifier diode rectifying a first portion of the AC power into the DC power;

a second rectifier diode electrically connected between the first input terminal and a second output terminal, the second rectifier diode rectifying a second portion of the AC power into the DC power, a voltage of the DC power being measurable across the first and second output terminals;

a plurality of PFC switches;

an inductor electrically connected between a second input terminal and two of the plurality of PFC switches; and

first and second bypass diodes that, when switching of the PFC switches is disabled, provide a current path past the plurality of PFC switches and the inductor.

2. The PFC system of claim 1 wherein a first one of the first and second bypass diodes is electrically connected between the second input terminal and the first output terminal, and

wherein a second one of the first and second bypass diodes is electrically connected between the first input terminal and the second output terminal.

3. The PFC system of claim 1 wherein a first one of the first and second bypass diodes is electrically connected at a cathode to the second input terminal and at an anode to a negative one of the first and second output terminals, and

wherein a second one of the first and second bypass diodes is electrically connected at a cathode to a positive one of the first and second output terminals and at an anode to the second input terminal.

4. The PFC system of claim 1 wherein the first and second bypass diodes are forward biased when the switching is disabled and reversed biased when the switching is enabled.

5. The PFC system of claim 1 further comprising:

a third rectifier diode electrically connected in parallel with the first rectifier diode between the first input terminal and the first output terminal; and

a fourth rectifier diode electrically connected in parallel with the second rectifier diode between the first input terminal and the second output terminal.

6. The PFC system of claim 1 wherein the first and second bypass diodes each include a power diode.

7. The PFC system of claim 1 wherein a maximum switching frequency capability of the first and second bypass diodes is less than a predetermined minimum switching frequency of the plurality of PFC switches.

8. The PFC system of claim 1 further comprising second and third inductors,

wherein the plurality of PFC switches includes three pairs of PFC switches,

wherein the second inductor is electrically connected between the second input terminal and a first connecting node between a first pair of the three pairs of PFC switches, and

wherein the third inductor is electrically connected between the second input terminal and a second connecting node between a second pair of the three pairs of PFC switches.

9. The PFC system of claim 1 further comprising a second inductor,

wherein the plurality of PFC switches includes two pairs of PFC switches,

wherein the second inductor is electrically connected between the second input terminal and a connecting node between one of the two pairs of PFC switches, and

further comprising a plurality of anti-parallel diodes, one of the plurality of anti-parallel diodes electrically connected anti-parallel to each of the plurality of PFC switches, respectively.

10. The PFC system of claim 1 wherein, when the switching is enabled, the PFC switches increase the voltage of the DC power to greater than a peak voltage of the AC power.

11. The PFC system of claim 1 further comprising a module that selectively disables the switching based on a current demand and at least one parameter determined based on the AC power.

12. A power factor correction (PFC) system comprising:

a PFC module receiving an alternating current (AC) power, outputting a direct current (DC) power, and selectively performing switching;

an input error detection module selectively indicating that a first error is present based on at least one parameter determined based on the AC power;

a negative current demand detection module selectively indicating that a second error is present when a current demand is negative; and

a module disabling the switching when at least one of the first and second errors is present.

13. The PFC system of claim 12 wherein the input error detection module selectively indicates that the first error is present when a first magnitude of a first voltage of the AC power is less than a first predetermined voltage and a second magnitude of a difference between the first voltage and a second voltage of a signal generated to reflect the first voltage is greater than a second predetermined voltage.

14. The PFC system of claim 13 wherein the input error detection module indicates that the first error is absent when, for less than a predetermined period, the first and second magnitudes are less than and greater than the first and second predetermined voltages, respectively.

15. The PFC system of claim 12 wherein the input error detection module indicates that the first error is present when a first magnitude of a change in a difference is greater than a predetermined voltage, the difference being between a first voltage of the AC power and a second voltage of a signal generated to reflect the first voltage.

16. The PFC system of claim 15 wherein the input error detection module selectively transitions from indicating that the first error is present to indicating that the first error is absent when, for a predetermined period, the first magnitude is less than the predetermined voltage and at least one of a second magnitude of the first voltage is greater than a second predetermined voltage and a third magnitude of the difference is less than a third predetermined voltage.

17. The PFC system of claim 16 wherein the input error detection module selectively transitions from indicating that the first error is present to indicating that the first error is absent when, for a second predetermined period, the second magnitude is greater than a fourth predetermined voltage and the first magnitude is less than a fifth predetermined voltage.

18. The PFC system of claim 17 wherein the input error detection module transitions from indicating that the first error is present to indicating that the first error is absent at a zero-crossing.

19. The PFC system of claim 12 further comprising a low duty cycle detection module indicating that a third error is present when a desired duty cycle of the switching is less than a predetermined minimum duty cycle and indicating that the third error is absent when the desired duty cycle is less than the predetermined minimum duty cycle and the current demand is greater than a predetermined current,

wherein the module disables the switching when at least one of the first, second, and third errors is present.

20. A method of operating a power factor correction (PFC) system, the method comprising:

receiving, at the PFC system, alternating current (AC) power;

selectively switching a plurality of switches of the PFC system to generate direct current (DC) power based on the AC power;

selectively indicating that a first error is present based on at least one parameter determined based on the AC power;

selectively indicating that a second error is present when a current demand is negative; and

disabling the switching when at least one of the first and second errors is present.