Power factor correction circuits and methods including partial power factor correction operation for boost and buck power converters

Patent metadata

Field	Value
Publication number	US-10312798-B2
Application number	US-201715487151-A
Country	US
Kind code	B2
Filing date	Apr 13, 2017
Priority date	Apr 15, 2016
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

A PFC circuit is provided. A bridge rectification circuit receives an AC voltage and generates a rectified AC voltage. A power converter converts the rectified AC voltage to a first DC voltage, where the power converter includes a switch and supplies the first DC voltage to a DC bus to power a compressor. A current sensor detects an amount of current. A control module, while operating in a correction mode: based on the rectified AC voltage, a phase angle of the rectified AC voltage, a second DC voltage of the DC bus, or the detected amount of current, control operation of the switch to transition between operating in a high activity mode and an inactive or low activity mode; transition the switch between open and closed states while in the high and low activity modes; and maintain the power converter in an OFF state while in the inactive mode.

First claim

What is claimed is:

1. A power factor correction circuit comprising:
a bridge rectification circuit configured to (i) receive an alternating current (AC) voltage, and (ii) generate a rectified AC voltage;
a power converter configured to convert the rectified AC voltage to a first direct current (DC) voltage, wherein the power converter comprises a switch and supplies the first DC voltage to a DC bus to power a compressor;
a current sensor configured to detect an amount of current (i) passing through the power converter, or (ii) returning from an output of the power factor correction circuit; and
a control module configured to, while operating in a partial power factor correction mode,
based on the rectified AC voltage, a phase angle of the rectified AC voltage, a second DC voltage, or the detected amount of current, control operation of the switch to transition between operating in (i) a high activity mode and (ii) an inactive mode or a low activity mode, wherein the second DC voltage is a detected DC voltage of the DC bus,
transition the switch between an open state and a closed state while in the high activity mode and the low activity mode; and
maintain the power converter in an OFF state while in the inactive mode.

2. The power factor correction circuit of claim 1 , wherein the control module is configured to, based on the rectified AC voltage, the phase angle of the rectified AC voltage, the second DC voltage, and the detected amount of current, control operation of the switch to transition between operating in (i) the high activity mode and (ii) the inactive mode or the low activity mode.

3. The power factor correction circuit of claim 1 , further comprising a driver configured to control operation of the switch based on an output signal,
the control module is configured to, based on the rectified AC voltage, the second DC voltage, and the detected amount of current, generate the output signal to transition the driver between operating in (i) the high activity mode and (ii) the inactive mode or the low activity mode.

4. The power factor correction circuit of claim 1 , wherein the control module is configured to:
transition the switch between the open state and the closed state at a first frequency while in the high activity mode; and
transition the switch between the open state and the closed state at a second frequency while in the low activity mode, wherein the second frequency is less than the first frequency.

5. The power factor correction circuit of claim 1 , wherein the control module is configured to:
operate the switch at a first duty cycle while in the high activity mode; and
operate the switch at a second duty cycle while in the low activity mode,
wherein the first duty cycle is less than the second duty cycle, such that the ON time of the switch per cycle is shorter during the high activity mode than during the low activity mode, or (ii) the OFF time of the switch per cycle is longer during the high activity mode than during the low activity mode.

6. The power factor correction circuit of claim 1 , wherein the control module is configured to:
operate the switch at a first duty cycle while in the high activity mode; and
operate the switch at a second duty cycle while in the low activity mode,
wherein the first duty cycle is greater than the second duty cycle, such that the ON time of the switch per cycle is longer during the high activity mode than during the low activity mode, or (ii) the OFF time of the switch per cycle is shorter during the high activity mode than during the low activity mode.

7. The power factor correction circuit of claim 1 , wherein the control module is configured to, based on the phase angle of the first DC voltage, transition the power converter between (i) the high activity mode and (ii) the inactive mode or the low activity mode.

8. The power factor correction circuit of claim 1 , wherein the control module is configured to (i) based on a load on the compressor, transition between the partial power factor correction mode and a full power factor correction mode, (ii) while in the partial power factor correction mode, transition the power converter between (a) the high activity mode and (b) the inactive mode or the low activity mode, and (iii) maintain operation in the high activity mode while in the full power factor correction mode.

9. The power factor correction circuit of claim 1 , the bridge rectification circuit comprises:
a first bridge rectifier configured to (i) receive the AC voltage, and (ii) generate the rectified AC voltage; and
a second bridge rectifier configured to (i) receive the AC voltage, (ii) generate a second rectified AC voltage, and (ii) bypass the first bridge rectifier to provide the second rectified AC voltage to the DC bus.

10. The power factor correction circuit of claim 1 , wherein the control module is configured to:
determine the phase angle of the rectified AC voltage;
if the phase angle is a start time for operating in the high activity mode, then transition to the high activity mode including transitioning the switch between the open state and the closed state to boost the second DC voltage of the DC bus to a predetermined DC voltage; and
if the phase angle is an end time for operating in the high activity mode, then transition to the inactive mode or the low activity mode.

11. The power factor correction circuit of claim 10 , wherein the control module is configured to:
generate a commanded DC voltage based on the rectified AC voltage, a phase angle of the rectified AC voltage, the second DC voltage, or the detected amount of current, wherein the power converter is a boost converter; and
if the phase angle is a start time for operating in the high activity mode and the second DC voltage is less than or equal to the commanded DC voltage, then operate in the high activity mode including transitioning the switch between the open state and the closed state to boost the second DC voltage of the DC bus to the predetermined DC voltage.

12. The power factor correction circuit of claim 1 , wherein:
the power converter is a boost converter; and
the control module is configured to
determine the phase angle of the rectified AC voltage,
if the phase angle is a start time for operating in the inactive mode or the low activity mode, then transition to the inactive mode or the low activity mode, wherein if the control module transitions to the low activity mode, the control module transitions the switch between the open state and the closed state at a lower frequency than when in the high activity mode, and
if the phase angle is an end time for operating in the inactive mode or the low activity mode, then transition to the high activity mode.

13. The power factor correction circuit of claim 1 , wherein the control module is configured to:
generate a commanded DC voltage based on the rectified AC voltage, a phase angle of the rectified AC voltage, the second DC voltage, or the detected amount of current, wherein the power converter is a buck converter; and
if the phase angle is a start time for operating in the inactive mode or the low activity mode and the second DC voltage is less than or equal to the commanded DC voltage, then transition to the inactive mode or the low activity mode.

14. The power factor correction circuit of claim 1 , further comprising an output module configured to:
determine a peak current level of the detected amount of current;
based on a timer, compare the peak current level to (i) a maximum current level, and (ii) a minimum current level;
update an adjustment value based on the (i) comparison between the

Assignees

• Emerson Climate Technologies
• Emerson Electric Co

Inventors

• Green Charles E
• Marcinkiewicz Joseph G
• BOCKHORST Kraig

Classifications

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• F25B49/025

  Motor control arrangements · CPC title

• F25B2600/024

  by controlling the electric parameters, e.g. current or voltage · CPC title

• H02M7/53871

  with automatic control of output voltage or current · CPC title

• H02P5/74

  controlling two or more AC dynamo-electric motors (H02P5/46, H02P5/60 take precedence) · CPC title