JP2005172653A - Lifetime monitoring device of power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for always monitoring automatically accurately the lifetime of a power supply device. <P>SOLUTION: The lifetime of the power supply device is determined by utilizing the fact that the lifetime of the power supply device is originated in the lifetime of an electrolytic capacitor and that the lifetime of the electrolytic capacitor appears as an increase of a ripple voltage of an output voltage of the device. Since a noise component has the most adverse effect on a load, in the ripple voltage, the lifetime is determined from the increasing rate of the noise component in the ripple voltage. A ripple voltage detection part 11 always detects the ripple voltage included in the output voltage from the power supply device, and acquires a lifetime determination output of the power supply device when the ripple voltage exceeds a set level. Detection of the ripple voltage is performed relative to the noise component. A band selecting circuit 12 selects and sets from among an AC ripple noise, a ripple, a noise, a switching ripple and an AC ripple included in the output voltage. A standard setting circuit 13 sets the set level for increase detection of the ripple voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a monitoring device for determining the life of a power supply device that requires high reliability, such as a power supply device for a protection monitoring control system of a social infrastructure directly connected to a lifeline such as a substation.

  Social infrastructure protection monitoring control systems that are directly connected to lifelines such as substations often require a design life of 23 years.

  There is a great need for a power supply device that supplies power to such a protection monitoring control system so as to widen a maintenance interval represented by replacement of an electrolytic capacitor.

  In addition to users who regularly replace for preventive maintenance, other interlocks are prepared and users are replaced after the power supply breaks down. There is a growing need to perform maintenance on the verge of breaking rather than regularly.

  Currently, there is one that measures a ripple current flowing in a storage battery or a capacitor used in an uninterruptible power supply and monitors the deterioration state of the capacitor or the storage battery from the ripple current value (see, for example, Patent Document 1).

  Another method is to measure the temperature of the electrolytic capacitor and repeat the life calculation with a microcomputer (for example, see Patent Document 2).

In addition, there are a DC power source and an AC power source as power supply devices to be monitored for life. In order to reduce the size and weight of DC power supplies, many switching power supply systems are adopted. In addition, an uninterruptible power supply composed of a CVCF inverter having a fixed voltage and a fixed frequency is often used as the AC power supply.
Japanese Patent Laid-Open No. 09-121471 Japanese Patent Laid-Open No. 2001-165879

  In the method of Patent Document 1, since the ripple current of the fundamental frequency component of the power source flowing in the capacitor or the like is measured, the deterioration of the capacitor or the storage battery alone is determined, and the life of the power supply device is not determined.

  In the method of measuring the temperature of the electrolytic capacitor and repeating the lifetime calculation with a microcomputer as in Patent Document 2, it is a calculated value to the last and has a large error from the actual lifetime. In addition, a complicated and large-scale processing apparatus is required.

  Currently, it is conceivable to use a commercially available ripple noise meter to monitor the life of a power supply, prepare predetermined criteria, measure ripple noise with manpower, and determine whether maintenance is necessary. Is not in full swing.

    SUMMARY OF THE INVENTION An object of the present invention is to provide a monitoring device that has flexibility in monitoring the life of a power supply device, and that can always perform automatic monitoring accurately without complicating the device configuration.

  In the present invention, the life of the power supply device can be regarded as the life of the electrolytic capacitor used in the device, and any one of the electrolytic capacitors provided in the device is increased as the ripple voltage included in the output of the power supply device. Focus on the fact that it appears, determine the life of the power supply by detecting the ripple voltage at the output terminal of the power supply, and pay attention to the fact that the noise component of the ripple voltage has the most adverse effect on the load. Of the ripple voltage included in the voltage, the life is determined from whether or not the noise component has exceeded the set level, thereby solving the above-mentioned problems and characterized by the following configuration.

(1) A monitoring device for determining the life of a power supply device,
A ripple voltage included in the output voltage of the power supply device is always detected, and when the ripple voltage exceeds a set level, the life of the power supply device is determined.

  (2) The detection of the ripple voltage is characterized in that when the noise of the ripple voltage exceeds a set level, a life determination output of the power supply device is obtained.

  (3) The detection of the ripple voltage is characterized in that a ripple voltage to be detected can be selected and set among AC ripple noise, ripple, noise, switching ripple, and AC ripple.

  (4) The detection of the ripple voltage is characterized in that the set level can be set.

  As described above, according to the present invention, the life of the power supply device is determined based on the ripple voltage included in the output voltage of the power supply device, and further, the life is determined from the noise component of the ripple voltage. It has the following effects.

  (1) Since the life of the power supply device is determined based on the fact that the life of many electrolytic capacitors provided in the power supply device appears as a ripple voltage of the output voltage of the power supply device, the life can be reliably monitored and judged. Along with this, it can be used to the end of the power supply life, and the maintenance cost of the user can be reduced.

  (2) The inspection cost can be reduced by constantly monitoring the end of life.

  (3) Since the actual ripple increase is monitored, the error is small.

  (4) Since it is possible to set judgment criteria such as setting of monitoring ripple waveform and increase amount, the user can freely set a safety margin for each load.

  (5) When the life is determined from an increase in the noise component of the ripple voltage, reliability can be improved as a power supply device for an important load such as a computer.

  (6) The apparatus configuration is not complicated and is inexpensive.

  FIG. 1 is a functional block diagram of a monitoring apparatus showing an embodiment of the present invention. In the figure, reference numerals 1 to 6 denote configuration examples of the power supply device for the protection monitoring control system, which are shown as switching type power supply devices.

  Ripple or the like is removed from the direct current output of the direct current power source 1 composed of a rectifier or the like by an input smoothing circuit 2 composed of an electrolytic capacitor or the like. The switching unit 3 composed of a high-frequency transformer and a semiconductor switch converts and outputs high-frequency power of a predetermined voltage by high-frequency switching control of the semiconductor switch by the control unit 4. The filter 5 removes a switching frequency component from the output of the switching unit 3. The output smoothing circuit 6 rectifies and smoothes the high-frequency power passed through the filter 5 to convert it into DC power, and supplies DC power of a predetermined voltage to a load 7 such as a computer.

  In such a power supply device, the lifetime can be regarded as the lifetime of the electrolytic capacitor. That is, among the components used in the power supply device, the aluminum electrolytic capacitor is the component having the shortest life. Other parts having a lifetime include a resin such as an insulating material, but they have a lifetime of 20 to 30 years or more, and hardly cause a problem when a general electronic device is targeted.

  Therefore, in this embodiment, the lifetime of the aluminum electrolytic capacitor is detected to determine the lifetime of the power supply device. The life of this electrolytic capacitor is such that the capacitance falls below the allowable value (dry up: evaporation phenomenon of the electrolyte used in the electrolytic capacitor), the dielectric loss tangent (tan δ) increases, or the leakage current increases. Since this phenomenon appears as an increase in the ripple voltage, the ripple voltage is detected to determine the life of the electrolytic capacitor, that is, the life of the power supply device.

  Here, the circuit portion in which the aluminum electrolytic capacitor is used in the power supply device is mainly provided in the input / output smoothing circuits 2 and 6, the internal auxiliary power supply circuit, the phase correction circuit of the control unit 4, etc. The effect on the power supply differs depending on the end of the service life.

・ Input smoothing circuit: High ripple voltage → Power supply stop ・ Output smoothing circuit: High ripple voltage → Rectangular wave output voltage ・ Auxiliary power supply circuit: Control operation stopped → Power supply stop ・ Phase correction of control circuit: Uncorrectable → Output oscillation In the embodiment, the deterioration of the electrolytic capacitor used in any of the above circuits appears as an increase in the ripple voltage at the output of the output smoothing circuit 6, and the ripple voltage included in the output has the greatest influence on the operation of the load. Paying attention to this, the ripple voltage included in the output voltage of the power supply apparatus determines the life of the apparatus.

  In FIG. 1, reference numerals 11 to 14 denote monitoring apparatuses according to the present embodiment. The ripple detection unit 11 detects a ripple voltage included in a DC output supplied from the rectifying / smoothing circuit 6 to the load 7 and determines the life of the power supply device by monitoring the ripple voltage.

  Here, the ripple voltage is as shown in FIG. 2, and can be roughly classified into the following five types.

(A) AC ripple noise (b) Ripple (c) Noise (d) Switching ripple (e) AC ripple Of these, the increase in ripple voltage generally has an adverse effect on computers such as the load 7 in general. For this reason, it is preferable that the voltage increase rate (or increase amount) of the above (c) noise is set in advance, and the life is determined when it exceeds this.

  The band selection circuit 12 makes it possible to select and set the band of the ripple to be detected among the above five types of ripple voltages as the band detected by the ripple voltage detector 11. In this setting, for example, the circuit constant of the band filter is made variable, and (c) a noise band is set. The reference setting circuit 13 sets the increase rate of the noise voltage detected by the ripple voltage detection unit 11, for example. In this setting, for example, the voltage dividing ratio of the voltage dividing circuit for the reference voltage is made variable and can be set to 50%, for example.

  The ripple voltage detection unit 11 detects whether or not the noise component has exceeded the set increase rate based on the settings by the band selection circuit 12 and the reference setting circuit 13. The determination output unit 14 generates a life determination output of the power supply device when a detection output is made to the ripple voltage detection unit 11.

  The ripple voltage detection unit 11 extracts only the voltage component of (c) noise, for example, by passing the voltage signal of the power line of the load 7 through a narrow band filter, amplifies the noise voltage with an amplifier, and amplifies this The voltage is rectified by a diode and smoothed by a capacitor and converted to a DC voltage, and the voltage comparison circuit detects whether or not the DC voltage has reached a level exceeding a set increase rate.

  Although the above monitoring apparatus shows the case where it applies to monitoring of a switching type power supply device, it can apply to monitoring of AC power supplies, such as an uninterruptible power supply, and can obtain an equivalent effect.

The functional block diagram of the monitoring apparatus which shows embodiment of this invention. The wave form diagram explaining the kind of ripple voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Input smoothing circuit 3 Switching part 4 Control part 5 Filter 6 Output smoothing circuit 7 Load 11 Ripple voltage detection part 12 Band selection circuit 13 Reference setting circuit 14 Judgment output part

Claims (4)

A monitoring device for determining the life of a power supply device,
A life monitoring device for a power supply device, characterized in that a ripple voltage included in an output voltage of the power supply device is always detected, and the life of the power supply device is determined when the ripple voltage exceeds a set level.   2. The power supply device life monitoring apparatus according to claim 1, wherein the ripple voltage is detected by obtaining a life determination output of the power supply device when noise exceeds a set level in the ripple voltage.   The life of the power supply apparatus according to claim 1 or 2, wherein the ripple voltage is detected by selecting a ripple voltage to be detected from AC ripple noise, ripple, noise, switching ripple, and AC ripple. Monitoring device.   The life monitoring apparatus for a power supply apparatus according to any one of claims 1 to 3, wherein the setting of the setting level is enabled for detection of the ripple voltage.

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