# US 10,312,798 B2 · Power factor correction circuits and methods including partial power factor correction operation for boost and buck power converters

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- Number: US 10,312,798 B2
- Document ID: US10312798B2
- Status: Granted
- Kind: B2
- Application number: 15/487,151
- Filed: 2017-04-13
- Published: 2017-10-19
- Granted: 2019-06-04
- Earliest claimed: 2016-04-15
- Assignees: Emerson Electric Co.
- Applicants: Emerson Climate Technologies, Inc.
- Inventors: Charles E. Green; Joseph G. Marcinkiewicz; Kraig Bockhorst
- Web page: https://patentgrep.com/patent/US10312798B2

## CPC

- H02M 1/4225: {using a non-isolated boost converter}
- F25B 49/025: {Motor control arrangements}
- H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M 1/14: Arrangements for reducing ripples from DC input or output
- H02M 1/32: Means for protecting converters other than automatic disconnection
- H02M 1/42: Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
- H02M 5/458: using semiconductor devices only
- H02M 7/06: using discharge tubes without control electrode or semiconductor devices without control electrode
- H02P 5/74: controlling two or more AC dynamo-electric motors (H02P5/46, H02P5/60 take precedence)
- H02P 23/26: Power factor control [PFC]
- H02P 27/06: using DC to AC converters or inverters (H02P27/05 takes precedence)
- F25B 2600/021: Inverters therefor
- F25B 2600/024: by controlling the electric parameters, e.g. current or voltage
- F25B 2600/111: of condenser fans
- F25B 2700/151: of the compressor motor
- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- H02M 1/0032: {Control circuits allowing low power mode operation, e.g. in standby mode}
- H02M 1/008: {Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators}
- H02M 1/327: {against abnormal temperatures}
- H02M 1/4208: {Arrangements for improving power factor of AC input}
- H02M 1/4216: {operating from a three-phase input voltage (H02M1/4233 takes precedence)}
- H02M 1/4291: {by using a Buck converter to switch the input current}
- H02M 7/53871: {with automatic control of output voltage or current}
- Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

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.

### Claim 10 (depends on 1)

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.

### Claim 11 (depends on 10)

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.

### Claim 12 (depends on 1)

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.

### Claim 13 (depends on 1)

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.

### Claim 14 (depends on 1)

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 peak current level and the maximum current level, and (ii) comparison between the peak current level and the minimum current level; and
update a commanded DC voltage for the DC bus based on the adjustment value.

### Claim 15 (depends on 1)

The power factor correction circuit of claim 1, further comprising an output module configured to:
determine a peak voltage level of the received AC voltage or the rectified AC voltage;
determine a peak current level of the detected amount of current;
set a requested voltage to a minimum voltage for the compressor;
set a temporary voltage equal to the peak voltage level plus an offset value;
based on a timer, determine whether the requested voltage is greater than or equal to the temporary voltage; and
if the requested voltage is greater than or equal to the temporary voltage, set (i) an adjustment value for a commanded DC voltage equal to 0, and (ii) the commanded DC voltage equal to the requested voltage.

### Claim 16 (depends on 1)

The power factor correction circuit of claim 1, further comprising an output module configured to:
determine a peak voltage level of the received AC voltage or the rectified AC voltage;
determine a peak current level of the detected amount of current;
set a requested voltage to a minimum voltage for the compressor;
set a temporary voltage equal to the peak voltage level plus an offset value;
based on a timer, determine whether the peak current level is greater than a maximum current level; and
if the peak current level is greater than the maximum current level or an adjustment value for a commanded DC voltage is less than 0, set the adjustment value equal to 0 and the commanded DC voltage equal to the temporary voltage.

### Claim 17 (depends on 1)

The power factor correction circuit of claim 1, further comprising an output module configured to:
determine a peak voltage level of the received AC voltage or the rectified AC voltage;
determine a peak current level of the detected amount of current;
set a requested voltage to a minimum voltage for the compressor;
set a temporary voltage equal to the peak voltage level plus an offset value;
based on a timer, determine whether an adjustment value is greater than a difference between the temporary voltage and the requested voltage;
if the adjustment value for a commanded DC voltage is greater than a difference between the temporary voltage and the requested voltage, set (i) the adjustment value equal to the difference between the temporary voltage and the requested voltage, and (ii) the commanded DC voltage equal to the requested voltage; and
if the adjustment value for the commanded DC voltage is less than or equal to the difference between the temporary voltage and the requested voltage, set the commanded DC voltage equal to a difference between the temporary voltage and the adjustment value.

### Claim 18 (depends on 1)

The power factor correction circuit of claim 1, wherein:
the switch is a first switch;
the power converter comprises a plurality of switches and a plurality of diodes;
the plurality of switches include the first switch;
each of the plurality of diodes is connected in parallel with a respective one of the plurality of switches; and
the control module is configured to, based on the rectified AC voltage, the phase angle of the rectified AC voltage, the second DC voltage, or the detected amount of current, control operation of the plurality of switches to transition between operating in (i) the high activity mode and (ii) the inactive mode or the low activity mode.

### Claim 19 (depends on 1)

The power factor correction circuit of claim 1, wherein the control module is configured to (i) determine a load condition, (ii) if the load condition is determined to be a light load condition, maintain the switch in an ON state, (iii) if the load condition is determined to be a heavy load condition, pulse width modulate the switch.

### Claim 20 (depends on 1)

The power factor correction circuit of claim 1, wherein the control module is configured to (i) determine an inverter output current level, (ii) if at least one of the rectified AC voltage is less than a predetermined maximum voltage and the inverter output current level is less than a predetermined maximum current level, maintain the switch in an ON state, and (iii) if at least one of the rectified AC voltage is greater than or equal to the predetermined maximum voltage and the inverter output current level is greater than or equal to the predetermined maximum current level, pulse width modulate the switch.

### Claim 21 (depends on 1)

The power factor correction circuit of claim 1, wherein the control module is configured to (i) determine an inverter power circuit temperature, (ii) if at least one of the rectified AC voltage is less than a predetermined maximum voltage and the inverter power circuit temperature is inbound, maintain the switch in an ON state, and (iii) if at least one of the rectified AC voltage is greater than or equal to the predetermined maximum voltage and the inverter power circuit temperature is outbound, pulse width modulate the switch.

### Claim 22 (depends on 1)

The power factor correction circuit of claim 1, further comprising a relay, wherein the control module is configured to (i) determine a load condition, (ii) if the load condition is determined to be a light load condition, control the relay such that the power factor correction circuit receives single phase power and is performing a single phasing operation, (iii) if the load condition is determined to be a heavy load condition, control the relay such that the power factor correction circuit receives 3-phase power.

### Claim 23

A method of operating a power factor correction circuit, the method comprising:
receiving an alternating current (AC) voltage;
generating a rectified AC voltage via a bridge rectification circuit;
converting the rectified AC voltage to a first direct current (DC) voltage via a power converter, wherein the power converter comprises a switch;
supplying the first DC voltage to a DC bus to power a compressor;
detecting an amount of current (i) passing through the power converter, or (ii) returning from an output of the power factor correction circuit; and
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, controlling 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,
transitioning the switch between an open state and a closed state while in the high activity mode and the low activity mode, and
maintaining the power converter in an OFF state while in the inactive mode.

### Claim 24 (depends on 23)

The method of claim 23, comprising, 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.

### Claim 25 (depends on 23)

The method of claim 23, further comprising:
controlling operation of the switch via a driver based on an output signal; and
based on the rectified AC voltage, the second DC voltage, and the detected amount of current, generating 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.

### Claim 26 (depends on 23)

The method of claim 23, further comprising:
transitioning the switch between the open state and the closed state at a first frequency while in the high activity mode; and
transitioning 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.

### Claim 27 (depends on 23)

The method of claim 23, further comprising:
operating the switch at a first duty cycle while in the high activity mode; and
operating 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.

### Claim 28 (depends on 23)

The method of claim 23, further comprising:
operating the switch at a first duty cycle while in the high activity mode; and
operating 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.

### Claim 29 (depends on 23)

The method of claim 23, further comprising, based on the phase angle of the first rectified AC voltage, transitioning the power converter between (i) the high activity mode and (ii) the inactive mode or the low activity mode.

### Claim 30 (depends on 23)

The method of claim 23, further comprising:
based on a load on the compressor, transitioning between the partial power factor correction mode and a full power factor correction mode;
while in the partial power factor correction mode, transitioning the power converter between (i) the high activity mode and (ii) the inactive mode or the low activity mode; and
maintaining operation in the high activity mode while in the full power factor correction mode.

### Claim 31 (depends on 23)

The method of claim 23, further comprising:
receiving the AC voltage at a first bridge rectifier;
generating the rectified AC voltage via the first bridge rectifier;
receiving the AC voltage at a second bridge rectifier;
generating a second rectified AC voltage via the second bridge rectifier; and
bypassing the first bridge rectifier to provide the second rectified AC voltage to the DC bus.

### Claim 32 (depends on 23)

The method of claim 23, further comprising:
determining the phase angle of the rectified AC voltage;
if the phase angle is a start time for operating in the high activity mode, then transitioning 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 transitioning to the inactive mode or the low activity mode.

### Claim 33 (depends on 32)

The method of claim 32, further comprising:
generating 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 operating the switch 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.

### Claim 34 (depends on 23)

The method of claim 23, further comprising:
determining 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 transitioning to the inactive mode or the low activity mode, wherein if transitioning to the low activity mode, transitioning 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 transitioning to the high activity mode.

### Claim 35 (depends on 34)

The method of claim 34, further comprising:
generating 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 transitioning to operating the switch in the inactive mode or the low activity mode.

### Claim 36 (depends on 23)

The method of claim 23, further comprising:
determining a peak current level of the detected amount of current;
based on a timer, comparing the peak current level to (i) a maximum current level, and (ii) a minimum current level;
updating an adjustment value based on the (i) comparison between the peak current level and the maximum current level, and (ii) comparison between the peak current level and the minimum current level; and
updating a commanded DC voltage for the DC bus based on the adjustment value.

### Claim 37 (depends on 23)

The method of claim 23, further comprising:
determining a peak voltage level of the received AC voltage or the rectified AC voltage;
determining a peak current level of the detected amount of current;
setting a requested voltage to a minimum voltage for the compressor;
setting a temporary voltage equal to the peak voltage level plus an offset value;
based on a timer, determining whether the requested voltage is greater than or equal to the temporary voltage; and
if the requested voltage is greater than or equal to the temporary voltage, setting (i) an adjustment value for a commanded DC voltage equal to 0, and (ii) the commanded DC voltage equal to the requested voltage.

### Claim 38 (depends on 23)

The method of claim 23, further comprising:
determining a peak voltage level of the received AC voltage or the rectified AC voltage;
determining a peak current level of the detected amount of current;
setting a requested voltage to a minimum voltage for the compressor;
setting a temporary voltage equal to the peak voltage level plus an offset value;
based on a timer, determining whether the peak current level is greater than a maximum current level; and
if the peak current level is greater than the maximum current level or an adjustment value for a commanded DC voltage is less than 0, setting the adjustment value equal to 0 and the commanded DC voltage equal to the temporary voltage.

### Claim 39 (depends on 23)

The method of claim 23, further comprising:
determining a peak voltage level of the received AC voltage or the rectified AC voltage;
determining a peak current level of the detected amount of current;
setting a requested voltage to a minimum voltage for the compressor;
setting a temporary voltage equal to the peak voltage level plus an offset value;
based on a timer, determining whether an adjustment value is greater than a difference between the temporary voltage and the requested voltage;
if the adjustment value for a commanded DC voltage is greater than a difference between the temporary voltage and the requested voltage, setting (i) the adjustment value equal to the difference between the temporary voltage and the requested voltage, and (ii) the commanded DC voltage equal to the requested voltage; and
if the adjustment value for the commanded DC voltage is less than or equal to the difference between the temporary voltage and the requested voltage, setting the commanded DC voltage equal to a difference between the temporary voltage and the adjustment value.