Circuits, systems, methods, and software for power factor correction and/or control

Abstract

Circuits, systems, methods and software for controlling a power conversion and/or correcting and/or controlling a power factor in such conversion(s). The present invention generally takes a computational approach to reducing or minimizing zero current periods in the critical mode of power converter operation, and advantageously reduces zero current periods in the critical mode of power converter operation, thereby maximizing the power factor of the power converter in the critical mode and reducing noise that may be injected back into AC power lines. The present power factor controller allows for greater design flexibility, reduced design complexity, and reduced resolution and greater tolerance for error in certain parameter measurements useful in power factor correction and/or control.

1. A power factor controller, comprising:
 a circuit configured to determine and/or identify a period of a periodic power signal and a length of time from a beginning of said period during which a potential is applied to a power conversion switch; 
 a voltage calculator configured to determine at least a peak voltage of said periodic power signal; 
 logic configured to calculate a time period to open said power conversion switch in response to said length of time, said period, and said peak voltage; and 
 a voltage detector configured to determine a zero voltage at an input to a power converter operating on said periodic power signal. 
 
     
     
       2. The power factor controller of  claim 1 , further comprising a comparator configured to compare a voltage of said periodic power signal to a first reference voltage and provide a first relative voltage value to said voltage calculator. 
     
     
       3. The power factor controller of  claim 2 , wherein said comparator is configured to compare said voltage of said periodic power signal to a second reference voltage and provide a second relative voltage value to a said voltage detector configured to determine a said  zero voltage at an said input to a said power converter operating on said periodic power signal. 
     
     
       4. The power factor controller of  claim 3 , further comprising first and second analog-to-digital converters respectively configured to receive a voltage feedback from an output of said power converter and a current feedback in electrical communication with said power conversion switch. 
     
     
       5. The power factor controller of  claim 1 , further comprising a digital-to-analog converter configured to receive an output from said logic and provide an analog input in communication with said power conversion switch. 
     
     
       6. The power factor controller of claim  5  4, further comprising a notch filter configured to receive an output from said first analog-to-digital converter and a second filter configured to receive an output from said second analog-to-digital converter. 
     
     
       7. The power factor controller of  claim 1 , wherein said periodic power signal comprises an alternating current power signal. 
     
     
       8. The power factor controller of  claim 1 , further comprising a first filter configured to reduce or remove harmonic noise from an output of said power converter in response to an output voltage feedback signal. 
     
     
       9. The power factor controller of  claim 1 , wherein said logic comprises a digital signal processor. 
     
     
       10. The power factor controller of  claim 1 , further comprising a filter configured to reduce or remove noise from a current feedback signal. 
     
     
       11. A power factor controller, comprising:
 a circuit configured to determine and/or identify a period of a periodic power signal and a length of time from a beginning of said period during which a potential is applied to a power conversion switch; 
 a voltage calculator configured to determine at least a value of the a peak voltage of said periodic power signal; 
 logic configured to calculate a time period to open said power conversion switch in response to said length of time, said power signal period, and said value of the peak voltage; and 
 a comparator configured to compare a voltage of said periodic power signal to a first reference voltage and provide a first relative voltage value to said voltage calculator. 
 
     
     
       12. The power factor controller of  claim 11 , further comprising a digital-to-analog converter configured to receive an output from said logic and provide an analog input in communication with said power conversion switch. 
     
     
       13. The power factor controller of  claim 12 , further comprising first and second analog-to-digital converters respectively configured to receive a voltage feedback from an output of said a power converter and a current feedback in electrical communication with said power conversion switch. 
     
     
       14. The power factor controller of  claim 13 , further comprising a notch filter configured to receive an output from said first analog-to-digital converter and a second filter configured to receive an output from said second analog-to-digital converter. 
     
     
       15. A power factor controller, comprising:
 a circuit configured to determine and/or identify a period of a periodic power signal and a length of time from a beginning of said period during which a potential is applied to a power conversion switch; 
 a voltage calculator configured to determine at least a value of the a peak voltage of said periodic power signal; 
 logic configured to calculate a time period to open said power conversion switch in response to said length of time, said power signal period, and said value of the peak voltage; and 
 a digital-to-analog converter configured to receive an output from said logic and provide an analog input in communication with said power conversion switch. 
 
     
     
       16. The power factor controller of  claim 15 , further comprising first and second analog-to-digital converters respectively configured to receive a voltage feedback from an output of said a power converter and a current feedback in electrical communication with said power conversion switch. 
     
     
       17. The power factor controller of  claim 16 , further comprising a notch filter configured to receive an output from said first analog-to-digital converter and a second filter configured to receive an output from said second analog-to-digital converter. 
     
     
       18. A method of controlling a power converter, the method comprising:
 storing energy from a periodic power signal in said power converter in response to application of a potential to a switch in electrical communication with said power converter; 
 determining a period of said periodic power signal and a length of time from a beginning of said period during which said potential is applied to said switch; 
 determining a peak voltage of said periodic power signal; 
 calculating a time period to open said switch from said length of time, said period, and said peak voltage; and 
 opening said switch during said time period. 
 
     
     
       19. The method of  claim 18 , wherein determining said peak voltage comprises comparing a voltage of said periodic power signal to a first reference voltage, sampling an output of said comparing step to generate a plurality of power signal voltage samples, and determining a maximum power signal voltage sample value, wherein said peak voltage corresponds to said maximum power signal voltage sample value. 
     
     
       20. The method of  claim 19 , further comprising timing said power signal period and/or said length of time in response to a zero voltage indication. 
     
     
       21. The method of  claim 18 , further comprising determining a zero voltage at an input to said power converter. 
     
     
       22. The method of  claim 18 , wherein said periodic power signal comprises an alternating current power signal. 
     
     
       23. The method of  claim 18 , further comprising calculating said time period when said power converter is in a critical mode. 
     
     
       24. The method of  claim 18 , further comprising filtering harmonic noise from an output of said power converter and a current feedback signal.