Power-supply apparatus and power-supply method

Patent metadata

Field	Value
Publication number	US-11264892-B2
Application number	US-201816137597-A
Country	US
Kind code	B2
Filing date	Sep 21, 2018
Priority date	Sep 27, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A power-supply apparatus includes a power-supply circuit to which an input voltage and an input current are input, to include a switching element to be controlled by a control signal so as to generate an output voltage and an output current, a memory, and a processor coupled to the memory and the processor to calculate a first duty ratio of the control signal so that the output voltage approaches a target voltage, calculate a second duty ratio of the control signal for the switching element, based on the input voltage, the input current, the output voltage, and the output current, detect deterioration of the power-supply circuit, based on the first duty ratio and the second duty ratio, generate the control signal of the first duty ratio when the power-supply circuit has not deteriorated, and generate the control signal for stopping the power-supply circuit when the power-supply circuit has deteriorated.

First claim

What is claimed is:

1. A power-supply apparatus comprising:
a power supply circuit to which an input voltage and an input current are input, configured to include a switching element to be controlled by a control signal so as to generate an output voltage and an output current;
a memory; and
a processor coupled to the memory and the processor configured to:
calculate a first duty ratio of the control signal so that the output voltage approaches a target voltage;
calculate a second duty ratio of the control signal for the switching element, based on the input voltage, the input current, the output voltage, and the output current;
detect deterioration of the power supply circuit, based on the first duty ratio and the second duty ratio;
generate the control signal of the first duty ratio when the power supply circuit has not deteriorated; and
generate the control signal for stopping the power supply circuit when the power supply circuit has deteriorated,
in a case in which a ratio of the first duty ratio to the second duty ratio is proportional to the output current in a range in which the output current is larger than a first current threshold, the processor is configured to generate the control signal for stopping the power supply circuit when the ratio of the first duty ratio to the second duty ratio is larger than a first stop threshold and generate the control signal of the first duty ratio when the ratio of the first duty ratio to the second duty ratio is smaller than or equal to the first stop threshold,
in a case in which the ratio of the first duty ratio to the second duty ratio is inversely proportional to the output current in a range in which the output current is smaller than a second current threshold, the processor is configured to generate the control signal for stopping the power supply circuit when the ratio of the first duty ratio to the second duty ratio is larger than a second stop threshold and generate the control signal of the first duty ratio when the ratio of the first duty ratio to the second duty ratio is smaller than or equal to the second stop threshold, and
in a case in which a variation in the ratio of the first duty ratio to the second duty ratio with respect to the output current is within a threshold range, the processor is configured to generate the control signal for stopping the power supply circuit when the ratio of the first duty ratio to the second duty ratio is larger than a third stop threshold and generate the control signal of the first duty ratio when the ratio of the first duty ratio to the second duty ratio is smaller than or equal to the third stop threshold.

2. The power-supply apparatus according to claim 1 , wherein the processor is configured to:
determine a loss power by subtracting a product of the output voltage and the output current from a product of the input voltage and the input current,
determine a loss resistance corresponding to the loss power by dividing the loss power by a square of the output current, and
calculate the second duty ratio, based on the loss resistance and the input voltage, the output voltage, and the output current.

3. The power-supply apparatus according to claim 2 , wherein, when the output current is smaller than a current threshold, the loss resistance is set to a specific value.

4. The power-supply apparatus according to claim 2 , wherein the processor is configured to:
determine a load resistance by dividing the output voltage by the output current,
determine a sum of the load resistance and the loss resistance,
determine a product of the sum and the output current,
divide the product by the input voltage, and
calculate the second duty ratio based on a result of dividing the product.

5. The power-supply apparatus according to claim 4 , wherein the processor is configured to calculate the second duty ratio by multiplying the result of dividing the product by a turns ratio of a transformer in the power supply circuit.

6. The power-supply apparatus according to claim 1 , wherein the processor is configured to
generate the control signal for stopping the power supply circuit, when a ratio of the first duty ratio to the second duty ratio is larger than a stop threshold, and
generate the control signal of the first duty ratio, when the ratio of the first duty ratio to the second duty ratio is smaller than or equal to the stop threshold.

7. The power-supply apparatus according to claim 1 , wherein the processor is configured to generate a warning signal, when a ratio of the first duty ratio to the second duty ratio is larger than a warning threshold.

8. The power-supply apparatus according to claim 1 ,
wherein, in a case in which a ratio of the first duty ratio to the second duty ratio is proportional to the output current in a range in which the output current is larger than a first current threshold, the processor is configured to generate a first warning signal when the ratio of the first duty ratio to the second duty ratio is larger than a first warning threshold;
wherein, in a case in which the ratio of the first duty ratio to the second duty ratio is inversely proportional to the output current in a range in which the output current is smaller than a second current threshold, the processor is configured to generate a second warning signal when the ratio of the first duty ratio to the second duty ratio is larger than a second warning threshold; and
wherein, in a case in which a variation in the ratio of the first duty ratio to the second duty ratio with respect to the output current is within a threshold range, the processor is configured to generate a third warning signal when the ratio of the first duty ratio to the second duty ratio is larger than a third warning threshold.

9. The power-supply apparatus according to claim 1 ,
wherein, in a case in which a gradient of a ratio of the first duty ratio to the second duty ratio with respect to the output current is larger than a first positive value, the processor is configured to generate the control signal for stopping the power supply circuit when the ratio of the first duty ratio to the second duty ratio is larger than a first stop threshold and generate the control signal of the first duty ratio when the ratio of the first duty ratio to the second duty ratio is smaller than or equal to the first stop threshold;
wherein, in a case in which the gradient of the ratio of the first duty ratio to the second duty ratio with respect to the output current is smaller than a first negative value, the processor is configured to generate the control signal for stopping the power supply circuit when the ratio of the first duty ratio to the second duty ratio is larger than a second stop threshold and generate the control signal of the first duty ratio when the ratio of the first duty ratio to the second duty ratio is smaller than or equal to the second stop threshold; and
wherein, in a case in which the gradient of the ratio of the first duty ratio to the second duty ratio with respect to the output current is smaller than or equal to the first positive value and is larger than or equal to the first negative value, the processor is configured to generate the control signal for stopping the power supply circuit when the ratio of the first duty ratio to the second duty ratio is larger than a third stop threshold and generate the control signal of the first duty ratio when the ratio of the first duty ratio to the second duty ratio is not larger than the third stop threshold.

10. The power-supply apparatus according to claim 1 ,
wherein, in a case in which a gradient of a ratio of the first duty ratio to the second duty ratio with respect to the output current is larger th

Assignees

• Fujitsu Ltd

Inventors

• Nakao Hiroshi
• Yonezawa Yu
• Nakashima Yoshiyasu

Classifications

• H02M1/0009

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

• H02M3/33507

  with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence) · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H02M3/33515

  with digital control · CPC title

• H02M1/08

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