Method and apparatus for providing a power factor correction (PFC) compatible solution for electronic devices
Methods and apparatuses for providing a solution for incompatibility between nonsinusoidal waveform uninterruptible power supply (UPS) systems and active power factor correction (PFC) loads are disclosed. An embodiment of the invention includes generating a nonsinusoidal signal waveform (e.g., a voltage waveform), to be delivered to the load, with a pulse width modulation (PWM) duty width, sampling the nonsinusoidal signal waveform to collect output signal samples, and adjusting the duty width to control the nonsinusoidal signal waveform as a function of the output signal samples to deliver a desired signal characteristic (e.g., RMS signal level) to the load. In embodiments of the invention, the output duty width is adjusted differently in cases of rising and falling power consumption, respectively, by the load. Techniques disclosed herein find broad applicability in electronic devices, such as servers, computers, UPS systems and inverters and improve efficiency and reliability for end users and utility providers.
1. An electronic device comprising:
a microcontroller, configured to generate a nonsinusoidal signal waveform for delivery to a load by the electronic device, the microcontroller responsive to the nonsinusoidal signal waveform delivered to the load, the microcontroller further configured to:
sample the nonsinusoidal signal waveform to collect output signal samples; and
adjust at least one parameter of the nonsinusoidal signal waveform by adjusting generation of the nonsinusoidal signal waveform responsive to an effect of the load on the nonsinusoidal signal waveform, the effect of the load being due to the load's demand for more or less power and determined from the output signal samples collected, wherein the electronic device is a server.
2. The electronic device of claim 1 wherein the at least one parameter includes duty width.
3. The electronic device of claim 1 wherein the load includes an active power factor correction (PFC) controller.
4. The electronic device of claim 1 wherein the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect the output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
determine whether the load is demanding less power over time based on a comparison of a change in samples representing the nonsinusoidal signal waveform during the given cycle against a threshold.
5. The electronic device of claim 1 wherein the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect the output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle; and
determine whether consecutive cycles indicate that the load is demanding more power over time by comparing a change in samples representing the nonsinusoidal signal waveform from cycle-to-cycle against a threshold.
6. The electronic device of claim 1 wherein the at least one parameter includes duty width and the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect the output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle; and
re-calculate the duty width using a current cycle's peak output voltage if the current cycle's peak output voltage is less than the previous cycle's peak output voltage and, otherwise, re-calculate the duty width based on an average of the current cycle's peak output voltage and the previous cycle's peak output voltage.
7. The electronic device of claim 1 wherein the at least one parameter includes duty width, the nonsinusoidal waveform is a nonsinusoidal voltage waveform, and further wherein the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle; and
calculate a Root Mean Square (RMS) voltage for a present half cycle of a given cycle including all output voltage samples collected in the present half cycle and setting a voltage of the nonsinusoidal voltage waveform to zero if the RMS calculated has reached a nominal output voltage.
8. A method of controlling an output signal to be delivered to a load, the method comprising:
by a microcontroller of an electronic device, generating a nonsinusoidal signal waveform for delivery to the load;
by the microcontroller, sampling the nonsinusoidal signal waveform to collect output signal samples; and
by the microcontroller, adjusting at least one parameter of the nonsinusoidal signal waveform by adjusting the generating responsive to an effect of the load on the nonsinusoidal signal waveform, the effect of the load being due to the load's demand for more or less power and determined from the output signal samples collected, wherein the electronic device is a server.
9. The method of claim 8 wherein the at least one parameter includes duty width.
10. The method of claim 8 further comprising including an active power factor correction (PFC) controller in the load.
11. The method of claim 8 further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
determining whether the load is demanding less power over time based on a comparison of a change in samples representing the nonsinusoidal signal waveform during the given cycle against a threshold.
12. The method of claim 8 further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
determining whether consecutive cycles indicate that the load is demanding more power over time by comparing a change in samples representing the nonsinusoidal signal waveform from cycle-to-cycle against a threshold.
13. The method of claim 8 wherein the at least one parameter includes duty width, the method further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
re-calculating the duty width using a current cycle's peak output voltage if the current cycle's peak output voltage is less than the previous cycle's peak output voltage and, otherwise, re-calculating the duty width based on an average of the current cycle's peak output voltage and the previous cycle's peak output voltage.
14. The method of claim 8 wherein the at least one parameter includes duty width, the nonsinusoidal waveform is a nonsinusoidal voltage waveform, the method further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
calculating a Root Mean Square (RMS) voltage for a present half cycle of a given cycle including all output voltage samples collected in the present half cycle and setting a voltage of the nonsinusoidal voltage waveform to zero if the RMS calculated has reached a nominal output voltage.
15. The method of claim 8 further comprising:
adjusting the at least one parameter, in compensation for the load's demanding more or less power, to control the nonsinusoidal signal waveform in order to deliver a desired signal characteristic to the load, wherein the desired signal characteristic is a desired root mean square (RMS) signal level.
16. The method of claim 8 , wherein the at least one parameter includes duty width, the method further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis; and
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform, wherein, in a case of falling output signal samples, adjusting the at least one parameter includes increasing the duty width, and further wherein, in a case of rising output voltage samples, adjusting the at least one parameter includes decreasing the duty width, and optionally wherein decreasing the duty width matches the RMS signal level of output voltage samples to the desired RMS signal level.
17. The method of claim 8 , further comprising, by the microcontroller:
sampling the nonsinusoidal signal waveform on a cycle-to-cycle basis; and determining whether the load is demanding more power over time based on consecutive cycles, wherein adjusting the at least one parameter includes increasing a duty width of the nonsinusoidal signal waveform to compensate for the load's demanding more power.
18. An electronic device comprising:
a microcontroller, configured to generate a nonsinusoidal signal waveform for delivery to a load by the electronic device, the microcontroller responsive to the nonsinusoidal signal waveform delivered to the load, the microcontroller further configured to:
sample the nonsinusoidal signal waveform to collect output signal samples; and
adjust at least one parameter of the nonsinusoidal signal waveform by adjusting generation of the nonsinusoidal signal waveform responsive to an effect of the load on the nonsinusoidal signal waveform, the effect of the load being due to the load's demand for more or less power and determined from the output signal samples collected, wherein the electronic device is a computer.
19. The electronic device of claim 18 wherein the at least one parameter includes duty width.
20. The electronic device of claim 18 wherein the load includes an active power factor correction (PFC) controller.
21. The electronic device of claim 18 wherein the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect the output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
determine whether the load is demanding less power over time based on a comparison of a change in samples representing the nonsinusoidal signal waveform during the given cycle against a threshold.
22. The electronic device of claim 18 wherein the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect the output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle; and
determine whether consecutive cycles indicate that the load is demanding more power over time by comparing a change in samples representing the nonsinusoidal signal waveform from cycle-to-cycle against a threshold.
23. The electronic device of claim 18 wherein the at least one parameter includes duty width and the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect the output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle; and
re-calculate the duty width using a current cycle's peak output voltage if the current cycle's peak output voltage is less than the previous cycle's peak output voltage and, otherwise, re-calculate the duty width based on an average of the current cycle's peak output voltage and the previous cycle's peak output voltage.
24. The electronic device of claim 18 wherein the at least one parameter includes duty width, the nonsinusoidal waveform is a nonsinusoidal voltage waveform, and further wherein the microcontroller is further configured to:
sample the nonsinusoidal signal waveform to collect output signal samples on a cycle-to-cycle basis;
sample the nonsinusoidal signal waveform at multiple instants within a given cycle; and
calculate a Root Mean Square (RMS) voltage for a present half cycle of a given cycle including all output voltage samples collected in the present half cycle and setting a voltage of the nonsinusoidal voltage waveform to zero if the RMS calculated has reached a nominal output voltage.
25. A method of controlling an output signal to be delivered to a load, the method comprising:
by a microcontroller of an electronic device, generating a nonsinusoidal signal waveform for delivery to the load;
by the microcontroller, sampling the nonsinusoidal signal waveform to collect output signal samples; and
by the microcontroller, adjusting at least one parameter of the nonsinusoidal signal waveform by adjusting the generating responsive to an effect of the load on the nonsinusoidal signal waveform, the effect of the load being due to the load's demand for more or less power and determined from the output signal samples collected, wherein the electronic device is a computer.
26. The method of claim 25 wherein the at least one parameter includes duty width.
27. The method of claim 25 further comprising including an active power factor correction (PFC) controller in the load.
28. The method of claim 25 further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
determining whether the load is demanding less power over time based on a comparison of a change in samples representing the nonsinusoidal signal waveform during the given cycle against a threshold.
29. The method of claim 25 further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
determining whether consecutive cycles indicate that the load is demanding more power over time by comparing a change in samples representing the nonsinusoidal signal waveform from cycle-to-cycle against a threshold.
30. The method of claim 25 wherein the at least one parameter includes duty width, the method further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
re-calculating the duty width using a current cycle's peak output voltage if the current cycle's peak output voltage is less than the previous cycle's peak output voltage and, otherwise, re-calculating the duty width based on an average of the current cycle's peak output voltage and the previous cycle's peak output voltage.
31. The method of claim 25 wherein the at least one parameter includes duty width, the nonsinusoidal waveform is a nonsinusoidal voltage waveform, the method further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis;
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform; and
calculating a Root Mean Square (RMS) voltage for a present half cycle of a given cycle including all output voltage samples collected in the present half cycle and setting a voltage of the nonsinusoidal voltage waveform to zero if the RMS calculated has reached a nominal output voltage.
32. The method of claim 25 further comprising:
adjusting the at least one parameter, in compensation for the load's demanding more or less power, to control the nonsinusoidal signal waveform in order to deliver a desired signal characteristic to the load, wherein the desired signal characteristic is a desired root mean square (RMS) signal level.
33. The method of claim 25 , wherein the at least one parameter includes duty width, the method further comprising, by the microcontroller:
collecting the output signal samples on a cycle-to-cycle basis; and
sampling the nonsinusoidal signal waveform at multiple instants within a given cycle of the nonsinusoidal signal waveform, wherein, in a case of falling output signal samples, adjusting the at least one parameter includes increasing the duty width, and further wherein, in a case of rising output voltage samples, adjusting the at least one parameter includes decreasing the duty width, and optionally wherein decreasing the duty width matches the RMS signal level of output voltage samples to the desired RMS signal level.
34. The method of claim 25 , further comprising, by the microcontroller:
sampling the nonsinusoidal signal waveform on a cycle-to-cycle basis; and determining whether the load is demanding more power over time based on consecutive cycles, wherein adjusting the at least one parameter includes increasing a duty width of the nonsinusoidal signal waveform to compensate for the load's demanding more power.