# US 2011/0031942 A1 · System and method for reducing line current distortion

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2011/0031942 A1
- Document ID: US20110031942A1
- Status: Published application
- Kind: A1
- Application number: 12/852,578
- Filed: 2010-08-09
- Published: 2011-02-10
- Earliest claimed: 2009-08-10
- Assignees: Emerson Climate Technologies, Inc.
- Inventors: Charles E. Green
- Web page: https://patentgrep.com/patent/US20110031942A1

## CPC

- H02M 1/4208: {Arrangements for improving power factor of AC input}
- H02M 1/4225: {using a non-isolated boost converter}
- H02M 1/0085: {Partially controlled bridges}
- H02M 3/1584: {with a plurality of power processing stages connected in parallel}
- 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)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A power factor correction (PFC) system includes an adjustment module, a compensation module, and a duty cycle control module. The adjustment module generates N time advances based on N predetermined time advances and (N−1) time advance adjustments, wherein N is an integer greater than zero. The compensation module generates N compensated versions of an input alternating current (AC) line signal by predicting ahead of the input AC line signal using a gradient of a sinusoidal reference signal and the N time advances, respectively, wherein the sinusoidal reference signal is synchronized with the input AC line signal in phase and frequency. The duty cycle control module generates PFC duty cycles based on the N compensated versions of the input AC line signal.

## Claims

### Claim 1

A power factor correction (PFC) system, comprising:
an adjustment module that generates N time advances based on N predetermined time advances and (N−1) time advance adjustments, wherein N is an integer greater than zero;
a compensation module that generates N compensated versions of an input alternating current (AC) line signal by predicting ahead of the input AC line signal using a gradient of a sinusoidal reference signal and the N time advances, respectively, wherein the sinusoidal reference signal is synchronized with the input AC line signal in phase and frequency; and
a duty cycle control module that generates PFC duty cycles based on the N compensated versions of the input AC line signal.

### Claim 2 (depends on 1)

The PFC system of claim 1, further comprising:
a predicted zero-crossing detection module that generates an inversion signal based on predicted zero-crossings of the input AC line signal,
wherein the predicted zero-crossing detection module predicts the zero-crossings based on the input AC line signal,
wherein the PFC duty cycles are inverted based on the inversion signal.

### Claim 3 (depends on 2)

The PFC system of claim 2, wherein:
full inversion of the PFC duty cycles occurs over a first length of time,
the predicted zero-crossing detection module switches a state of the inversion signal based on a predicted zero-crossing of an advanced version of the input AC line signal,
the predicted zero-crossing detection module generates the advanced version of the input AC line signal by predicting ahead by a time advance, and
the time advance is based on a sum of a control system delay of the PFC system and half of the first length of time.

### Claim 4 (depends on 3)

The PFC system of claim 3, wherein the predicted zero-crossing detection module generates the advanced version of the input AC line signal by extrapolating a present value of the input AC line signal by the time advance along a present gradient of the sinusoidal reference signal.

### Claim 5 (depends on 2)

The PFC system of claim 2, further comprising:
a notch filter that generates a filtered AC signal by filtering out a predetermined frequency of the input AC line signal, wherein the predetermined frequency is based on a control system delay of the PFC system, wherein the compensation module generates the N compensated versions of the input AC line signal by predicting ahead of the filtered AC signal, and wherein the predicted zero-crossing detection module predicts the zero-crossings based on the filtered AC signal.

### Claim 6 (depends on 1)

The PFC system of claim 1, further comprising:
a notch filter that generates a filtered AC signal by filtering out a predetermined frequency of the input AC line signal, wherein the predetermined frequency is based on a control system delay of the PFC system, and wherein the compensation module generates the N compensated versions of the input AC line signal by predicting ahead of the filtered AC signal.

### Claim 7 (depends on 1)

The PFC system of claim 1, wherein for each version of the N compensated versions of the input AC line signal, the compensation module generates the version by extrapolating a present value of the input AC line signal by a corresponding one of the N time advances along a present gradient of the sinusoidal reference signal.

### Claim 8 (depends on 1)

The PFC system of claim 1, wherein the (N−1) time advance adjustments are based on differences between N measured currents having different phases, wherein N is an integer greater than one.

### Claim 9 (depends on 1)

The PFC system of claim 1, wherein the N predetermined time advances are set at design time.

### Claim 10

A method for power factor correction (PFC), comprising:
generating N time advances based on N predetermined time advances and (N−1) time advance adjustments, wherein N is an integer greater than zero;
generating N compensated versions of an input alternating current (AC) line signal by predicting ahead of the input AC line signal using a gradient of a sinusoidal reference signal and the N time advances, respectively, wherein the sinusoidal reference signal is synchronized with the input AC line signal in phase and frequency; and
generating PFC duty cycles based on the N compensated versions of the input AC line signal.

### Claim 11 (depends on 10)

The method of claim 10, further comprising:
generating an inversion signal based on predicted zero-crossings of the input AC line signal;
predicting the zero-crossings based on the input AC line signal; and
inverting the PFC duty cycles based on the inversion signal.

### Claim 12 (depends on 11)

The method of claim 11, wherein:
full inversion of the PFC duty cycles occurs over a first length of time;
switching a state of the inversion signal based on a predicted zero-crossing of an advanced version of the input AC line signal; and
generating the advanced version of the input AC line signal by predicting ahead by a time advance, wherein the time advance is based on a sum of a control system delay of a PFC system and half of the first length of time.

### Claim 13 (depends on 12)

The method of claim 12, further comprising generating the advanced version of the input AC line signal by extrapolating a present value of the input AC line signal by the time advance along a present gradient of the sinusoidal reference signal.

### Claim 14 (depends on 11)

The method of claim 11, further comprising:
generating a filtered AC signal by filtering out a predetermined frequency of the input AC line signal using a notch filter, wherein the predetermined frequency is based on a control system delay of a PFC system.

### Claim 15 (depends on 14)

The method of claim 14, further comprising:
generating the N compensated versions of the input AC line signal by predicting ahead of the filtered AC signal; and
predicting the zero-crossings based on the filtered AC signal.

### Claim 16 (depends on 10)

The method of claim 10, further comprising:
generates a filtered AC signal by filtering out a predetermined frequency of the input AC line signal using a notch filter, wherein the predetermined frequency is based on a control system delay of a PFC system; and
generating the N compensated versions of the input AC line signal by predicting ahead of the filtered AC signal.

### Claim 17 (depends on 10)

The method of claim 10, further comprising for each version of the N compensated versions of the input AC line signal, generating the version by extrapolating a present value of the input AC line signal by a corresponding one of the N time advances along a present gradient of the sinusoidal reference signal.

### Claim 18 (depends on 10)

The method of claim 10, wherein the (N−1) time advance adjustments are based on differences between N measured currents having different phases, wherein N is an integer greater than one.

### Claim 19 (depends on 10)

The method of claim 10, wherein the N predetermined time advances are set at design time.

### Claim 20

A method for power factor correction (PFC), comprising:
receiving an input alternating current (AC) line signal;
generating a filtered AC signal by filtering out a predetermined frequency of the input AC line signal using a notch filter, wherein the predetermined frequency is based on a control system delay of a PFC system;
generating a sinusoidal reference signal that is synchronized with the input AC line signal in phase and frequency;
generating N time advances based on N predetermined time advances and (N−1) time advance adjustments, wherein N is an integer greater than zero;
for each of N compensated versions of the input AC line signal, generating the version by extrapolating a present value of the filtered AC line signal by a corresponding one of the N time advances along a present gradient of the sinusoidal reference signal;
generating PFC duty cycles based on the N compensated versions of the input AC line signal;
predicting zero-crossings based on the filtered AC line signal;
generating an inversion signal based on predicted zero-crossings of the filtered AC line signal;
inverting the PFC duty cycles based on the inversion signal;
generating an advanced version of the filtered AC line signal by predicting ahead by a time advance that includes a sum of a control system delay of a PFC system and half of a time for full inversion of the PFC duty cycles; and
switching a state of the inversion signal based on a predicted zero-crossing of the advanced version of the filtered AC line signal.