Power conversion system with increased detection accuracy

Patent metadata

Field	Value
Publication number	US-12413151-B2
Application number	US-202318308926-A
Country	US
Kind code	B2
Filing date	Apr 28, 2023
Priority date	May 24, 2022
Publication date	Sep 9, 2025
Grant date	Sep 9, 2025

Abstract

A power conversion apparatus includes an input power terminal, an output power terminal, a power conversion circuit, a signal generation circuit, and a control circuit. The power conversion circuit converts supplied electric power and outputs the converted electric power. The power conversion circuit includes a sensor that generates a first detection signal corresponding to an output voltage or an output current. The signal generation circuit generates a second detection signal corresponding to the first detection signal. The control circuit controls operation of the power conversion circuit. The signal generation circuit includes a corrector, a photocoupler, and an output circuit. The corrector performs correction processing on the first detection signal. The photocoupler includes a light receiving device generating a light reception signal. The output circuit outputs the second detection signal corresponding to the light reception signal. The corrector performs the correction processing corresponding to a current transfer ratio of the photocoupler.

First claim

What is claimed is:

1. A power conversion apparatus comprising:
an input power terminal;
an output power terminal;
a power conversion circuit configured to convert electric power supplied via the input power terminal and to output converted electric power via the output power terminal, the power conversion circuit including a sensor configured to generate a first detection signal corresponding to an output voltage or an output current;
a signal generation circuit configured to generate a second detection signal corresponding to the first detection signal; and
a control circuit configured to control operation of the power conversion circuit,

wherein
the signal generation circuit includes
a corrector configured to perform correction processing on the first detection signal,
a photocoupler including a light emitting device and a light receiving device, the light emitting device being configured to emit light at a luminance corresponding to the first detection signal having undergone the correction processing, the light receiving device being configured to receive the light emitted by the light emitting device and to generate a light reception signal corresponding to an amount of the light received from the light emitting device, and
an output circuit configured to output the second detection signal corresponding to the light reception signal,
the corrector is configured to perform the correction processing corresponding to a current transfer ratio of the photocoupler,

the signal generation circuit includes
a first analog-to-digital conversion circuit configured to generate a first digital value by performing analog-to-digital conversion on the first detection signal,
a digital isolator,

a second analog-to-digital conversion circuit configured to generate a second digital value by performing analog-to-digital conversion on the second detection signal, and
a processing circuit configured to estimate the current transfer ratio, based on the first digital value supplied via the digital isolator and the second digital value, and to generate a parameter corresponding to the current transfer ratio estimated, and

the corrector is configured to perform, based on the parameter, the correction processing corresponding to the current transfer ratio.

2. The power conversion apparatus according to claim 1 , wherein the processing circuit is configured to correct the second detection signal, based on the first digital value supplied via the digital isolator and the second digital value.

3. The power conversion apparatus according to claim 1 , further comprising a signal terminal led to a terminal, the terminal allowing for output of the second detection signal of the signal generation circuit, wherein
the control circuit is configured to control the operation of the power conversion circuit, based on a voltage at the signal terminal and a voltage of the second detection signal.

4. The power conversion apparatus according to claim 2 , further comprising a signal terminal led to a terminal, the terminal allowing for output of the second detection signal of the signal generation circuit, wherein
the control circuit is configured to control the operation of the power conversion circuit, based on a voltage at the signal terminal and a voltage of the second detection signal.

5. A power conversion system comprising
a plurality of power conversion apparatuses, each of the power conversion apparatuses including:
an input power terminal;
an output power terminal;
a power conversion circuit configured to convert electric power supplied via the input power terminal and to output converted electric power via the output power terminal, the power conversion circuit including a sensor configured to generate a first detection signal corresponding to an output voltage or an output current;
a signal generation circuit configured to generate a second detection signal corresponding to the first detection signal;
a signal terminal led to a terminal, the terminal allowing for output of the second detection signal of the signal generation circuit; and
a control circuit configured to control operation of the power conversion circuit, based on a voltage at the signal terminal and a voltage of the second detection signal, wherein

the respective signal terminals of the power conversion apparatuses are coupled to each other,
the signal generation circuit includes
a corrector configured to perform correction processing on the first detection signal,
a photocoupler including a light emitting device and a light receiving device, the light emitting device being configured to emit light at a luminance corresponding to the first detection signal having undergone the correction processing, the light receiving device being configured to receive the light emitted by the light emitting device and to generate a light reception signal corresponding to an amount of the light received from the light emitting device, and
an output circuit configured to output the second detection signal corresponding to the light reception signal,
the corrector is configured to perform the correction processing corresponding to a current transfer ratio of the photocoupler,

the signal generation circuit includes
a first analog-to-digital conversion circuit configured to generate a first digital value by performing analog-to-digital conversion on the first detection signal,
a digital isolator,

a second analog-to-digital conversion circuit configured to generate a second digital value by performing analog-to-digital conversion on the second detection signal, and
a processing circuit configured to estimate the current transfer ratio, based on the first digital value supplied via the digital isolator and the second digital value, and to generate a parameter corresponding to the current transfer ratio estimated, and

the corrector is configured to perform, based on the parameter, the correction processing corresponding to the current transfer ratio.

6. The power conversion system according to claim 5 , wherein
the output power terminal of each of the power conversion apparatuses includes a power terminal and a reference power terminal, and
the power conversion apparatuses include
a first power conversion apparatus having the power terminal coupled to a first power node and the reference power terminal coupled to a second power node, and
a second power conversion apparatus having the power terminal coupled to the first power node and the reference power terminal coupled to the second power node.

7. The power conversion system according to claim 5 , wherein
the output power terminal of each of the power conversion apparatuses includes a power terminal and a reference power terminal, and
the power conversion apparatuses include
a first power conversion apparatus having the power terminal coupled to a first power node and the reference power terminal coupled to a second power node, and
a third power conversion apparatus having the power terminal coupled to the second power node and the reference power terminal coupled to a third power node.

8. The power conversion system according to claim 6 , wherein the power conversion apparatuses further include a third power conversion apparatus having the power terminal coupled to the second power node and the reference power terminal coupled to a third power node.

Assignees

• Tdk Corp

Inventors

• Takegami Eiji

Classifications

• H02M1/0009 Primary

  Devices or circuits for detecting current in a converter · CPC title

• H02M3/1584

  with a plurality of power processing stages connected in parallel · CPC title

• H02M3/33515

  with digital control · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M3/33523 Primary

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title