Power supply apparatus, control apparatus, and program therefor

Patent metadata

Field	Value
Publication number	US-2016006347-A1
Application number	US-201514747353-A
Country	US
Kind code	A1
Filing date	Jun 23, 2015
Priority date	Jul 4, 2014
Publication date	Jan 7, 2016
Grant date	—

Abstract

A power supply apparatus includes: an inductor to which an input voltage is applied; a switching element that switches a current flowing to the inductor on and off so as to cause an induced voltage to be generated; an electrolytic capacitor that smoothes the induced voltage and outputs the voltage to a load; and a control circuit that controls the switching element, wherein the control circuit outputs a second switching control signal obtained by superimposing a degradation detection-purpose signal for detecting degradation of the electrolytic capacitor on a first control signal, detects an output voltage output by switching performed by the switching element controlled by the second control signal, and estimates the degradation of the electrolytic capacitor by using the output voltage detected, a duty cycle of the first control signal, and a frequency component of the degradation detection-purpose signal contained in the output voltage detected.

First claim

What is claimed is:

1 . A power supply apparatus comprising:
a DC/DC converter comprising; an inductor to which an input voltage is applied; a switching element that switches a current flowing to the inductor on and off so as to cause an induced voltage to be generated; an electrolytic capacitor that smoothes a voltage responsive to the induced voltage and outputs the voltage to a load; and a control circuit that controls the switching element, wherein the control circuit outputs, to the switching element, a second control signal obtained by superimposing a degradation detection-purpose signal for detecting degradation of the electrolytic capacitor on a first control signal for controlling an output voltage to be output to the load, detects an output voltage output by switching performed by the switching element controlled by the second control signal, and estimates the degradation of the electrolytic capacitor by using the output voltage detected, a duty cycle of the first control signal, and a frequency component of the degradation detection-purpose signal contained in the output voltage detected.

2 . The power supply apparatus according to claim 1 ,
wherein the first control signal performs on and off control on the switching element at a switching frequency and changes the duty cycle so that the output voltage becomes a predetermined voltage, wherein the degradation detection-purpose signal has an estimation-purpose frequency lower than the switching frequency, and wherein the control circuit estimates a load current of the DC/DC converter by using the output voltage detected and the duty cycle, and estimates capacitance of the electrolytic capacitor from the load current and an estimation-purpose frequency component contained in the output voltage based on a correspondence relationship between the capacitance of the electrolytic capacitor, the load current and the estimation-purpose frequency component contained in the output voltage.

3 . The power supply apparatus according to claim 2 ,
wherein the control circuit calculates an output current output to the load of the DC/DC converter by dividing a difference between a value obtained by multiplying the input voltage by the duty cycle and the output voltage, by an internal resistance value of the DC/DC converter including internal resistances of the inductor and the switching element, and estimates, as the load current, a current obtained by extracting at least a frequency component lower than the estimation-purpose frequency component from the calculated output current.

4 . The power supply apparatus according to claim 3 ,
wherein the control circuit removes at least a frequency component not lower than the estimation-purpose frequency component from the output current, and estimates that an average value of the output current from which the frequency component not lower than the estimation-purpose frequency component has been removed is the load current.

5 . The power supply apparatus according to claim 2 ,
wherein the control circuit has a table indicating the estimation-purpose frequency component of the output voltage seen when the load current and the capacitance of the electrolytic capacitor are each changed.

6 . A control apparatus that controls a DC/DC converter including
an inductor to which an input voltage is applied, a switching element that switches a current flowing to the inductor on and off so as to cause an induced voltage to be generated, and an electrolytic capacitor that smoothes a voltage responsive to the induced voltage and outputs the voltage to a load, wherein the control apparatus outputs, to the switching element, a second control signal obtained by superimposing a degradation detection-purpose signal for detecting degradation of the electrolytic capacitor on a first control signal for controlling an output voltage to be output to the load, detects an output voltage output by switching performed by the switching element controlled by the second control signal, and estimates the degradation of the electrolytic capacitor by using the output voltage detected, a duty cycle of the first control signal, and a frequency component of the degradation detection-purpose signal contained in the output voltage detected.

7 . A computer-readable and non-transitory storage medium storing a program that controls a DC/DC converter including
an inductor to which an input voltage is applied, a switching element that switches a current flowing to the inductor on and off so as to cause an induced voltage to be generated, and an electrolytic capacitor that smoothes a voltage responsive to the induced voltage and outputs the voltage to a load, wherein the computer program causes a control apparatus to execute an operation, the operation comprising: outputting, to the switching element, a second control signal obtained by superimposing a degradation detection-purpose signal for detecting degradation of the electrolytic capacitor on a first control signal for controlling an output voltage to be output to the load; detecting an output voltage output by switching performed by the switching element controlled by the second control signal; and estimating the degradation of the electrolytic capacitor by using the output voltage detected, a duty cycle of the first control signal, and a frequency component of the degradation detection-purpose signal contained in the output voltage detected.

Assignees

• Fujitsu Ltd

Inventors

• Matsui Yoshinobu
• Hosoyama Hisato
• Sasaki Tomotake

Classifications

• G01R31/64

  Testing of capacitors · CPC title

• G05F1/46

  wherein the variable actually regulated by the final control device is DC (G05F1/625 takes precedence) · CPC title

• G01R31/40

  Testing power supplies (testing photovoltaic devices H02S50/10) · CPC title

• H02M3/155 Primary

  using semiconductor devices only · CPC title

• G01R31/003

  Environmental or reliability tests (of individual semiconductors G01R31/2642; of PCB's G01R31/2817; of IC's G01R31/2855; of other circuits G01R31/2849) · CPC title