JP2007129867A - Relay control method and relay controller for inrush current limiting circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relay control method and a relay controller for inrush current-limiting circuit that reduces the inrush current flowing via an electrical path between a power switch for an inputting or cutting off of alternating current and a power rectifying device when the power switch is closed, by connecting a current-limiting device in series and shorting the current-limiting device by a relay contact, after the passage of the inrush current. <P>SOLUTION: This relay control method allows a relay lifetime duration to be extended, as well as, power supply circuit reliability to be improved, by flowing the current into the current-limiting device so that the current is not made to flow into the relay, when a load current in an electric instrument is low, such as in waiting state. This relay control method also allows the relay contact for shorting the current-limiting device to be opened and the current to be controlled so as to be supplied to the load through the current-limiting device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In order to reduce the inrush current flowing through the circuit between the power switch and the power rectifying element when the power switch for turning on or off the AC voltage is closed, the present invention is connected in series with the circuit. The present invention relates to a relay control method for an inrush current limiting circuit and a relay control device for an inrush current limiting circuit, in which a current limiting element is connected to the current limiting element, and the current limiting element is short-circuited by a relay contact after passing an inrush current.

  A conventional inrush current reduction method is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-225432. The inrush current reduction method is connected in series to the electric circuit in order to reduce the inrush current flowing through the electric circuit between the power switch for turning on or off the AC power supply and the primary winding of the transformer. A current limiting element and a relay contact connected in parallel to the current limiting element and short-circuiting the current limiting element after a predetermined time after the power switch is turned on.

In the inrush current reduction method, an inrush current flows in the current limiting element when a power switch is turned on. However, since the resistance value of the current limiting element rapidly increases as the current increases, the inrush current can be reduced. It is done. And the said inrush current reduction method can eliminate the loss of electric power because the load current flows through the relay contact side by short-circuiting the relay contact connected in parallel to the current limiting element after a predetermined time.
JP 11-225432 A

  However, in the inrush current reducing method as described above, current is continuously supplied to the relay coil for connecting the relay contact while the power switch is turned on regardless of the magnitude of the load current. The current that continues to flow through the relay coil is accompanied by heat generation, causing deterioration of the relay due to aging, and shortening the life of the relay itself. Further, in order to prevent the relay from deteriorating, the reliability of the power supply device is maintained by using an expensive relay. In particular, a hot water storage hot water supply apparatus or an air conditioner that uses late-night power has been used for a long time and has a long product life, and therefore, a highly reliable product is required. Therefore, an expensive relay has been adopted.

  In order to solve the above problems, the present invention focuses on the fact that the load current in the standby state is small like the hot water storage type hot water supply apparatus or the air conditioner. An inrush current limiting circuit relay control method and an inrush current limiting circuit relay control device for flowing current to a load through a current limiting element without short-circuiting the current are provided.

(First invention)
According to a first aspect of the present invention, there is provided a relay control method for an inrush current limiting circuit for reducing an inrush current flowing through an electric path between the power switch and a power supply rectifying element when a power switch for turning on or off an AC voltage is closed. , Connecting a current limiting element in series to the electric circuit, short-circuiting the current limiting element by a relay contact after passing an inrush current, detecting a load current, and when the load current is lower than a predetermined value, The relay is turned off, and a current is supplied to a load through the current limiting element.

(Second invention)
The relay control device for an inrush current limiting circuit according to the second invention is for reducing the inrush current flowing through the electric circuit between the power switch and the power supply rectifier element when the power switch for turning on or off the AC voltage is closed. The current limiting element is connected in series to the electric circuit, and the current limiting element is short-circuited by a relay contact after passing an inrush current, and a current detection means for detecting a load current and the current limiting element are short-circuited Relay contact for turning on and off, relay means for turning on and off the relay contact, load current threshold storage means for preliminarily storing a load current threshold which becomes low resistance when the load current flows through the current limiting element, and the current detection The load for determining that the load current detected by the means is lower than the load current threshold stored in the load current threshold storage means stored in advance. And when the load current determining means determines that the load current value is less than or equal to a predetermined current value, the contact in the relay means shorting the current limiting element is opened, and the current limiting element And at least control means for controlling to supply a current to the load via.

(Third invention)
The relay control device for an inrush current limiting circuit according to the third aspect of the invention further comprises relay temperature detection means for detecting the temperature to which the relay means of the second invention is exposed, and the load current detected by the current detection means is greater than a predetermined threshold value. When the temperature is low and the temperature detected by the relay temperature detecting means is equal to or higher than a predetermined temperature, the relay contact that short-circuits the current limiting element is opened, and the load is passed through the current limiting element. Control is performed to supply current.

(Fourth invention)
The relay control device for an inrush current limiting circuit according to a fourth aspect of the invention includes a relay driving time measuring means for measuring the driving time of the relay means of the second invention or the third invention, and the relay driving time measuring means When the driving time of the relay means elapses above a certain level, it is provided with a notifying means for notifying that maintenance is necessary.

  According to the present invention, when it can be determined that the detected current detected by the current detecting means is small, the relay means for short-circuiting the current limiting element is turned OFF, and the load current is allowed to flow through the current limiting element, whereby the relay It is possible to reduce the deterioration due to heat generation of the means, improve the life of the relay means, and obtain a highly reliable and inexpensive inrush current limiting circuit relay control method and inrush current limiting circuit relay control device.

  According to the present invention, the relay temperature detecting means is provided in the vicinity of the relay means, and by monitoring the temperature in the vicinity of the relay means, in the case of a temperature that does not affect the life, the relay means is turned on regardless of the detected current, Power consumption in the current limiting element can be eliminated, and efficiency during standby can be improved.

  According to the present invention, by measuring the operating time of the relay means, it is possible to arrange for maintenance, repair, or replacement before the life of the relay means is exhausted.

(First invention)
The inrush current limiting circuit relay control method according to the first aspect of the present invention includes connecting a current limiting element in series to an electric circuit, and short-circuiting the current limiting element by a relay contact after passing the inrush current, thereby turning on or off an AC voltage. The inrush current flowing through the electric circuit between the power switch and the power rectifying element is reduced when the power switch for performing the operation is closed. The inrush current limiting circuit relay control method always detects a load current, and when the load current is lower than a predetermined value, turns off the relay and supplies current to the load via the current limiting element. Yes. That is, in the inrush current limiting circuit relay control method of the present invention, when the load current in the electronic device is small as in the standby state, by passing a current through the current limiting element, the current does not flow through the relay, In addition to extending the life of the relay, it improves the reliability of the power circuit. The load current during standby is for operating a microcomputer, for example. The current limiting element may be a simple fixed resistor.

(Second invention)
The inrush current limiting circuit relay control device according to the second aspect of the present invention reduces the inrush current flowing through the electric circuit between the power switch and the power rectifier when the power switch for turning on or off the AC voltage is closed. In order to do this, a current limiting element is connected in series with the electric circuit, and the current limiting element is short-circuited by a relay contact after passing an inrush current. The current detection means detects a load current flowing through the power supply circuit. The relay means is controlled to turn on and off a relay contact that short-circuits the current limiting element connected in series to the power supply circuit. The current limiting element may be a fixed resistance having a low resistance other than an element such as a so-called PTC.

  The load current threshold storage means stores in advance a load current threshold that becomes low resistance when the load current flows through the current limiting element. The load current determination means may determine whether or not the load current detected by the current detection means is lower than a load current threshold stored in the load current threshold storage means stored in advance. it can. When the load current determination unit determines that the load current value is equal to or less than a predetermined current value, the control unit opens the contact in the relay unit that short-circuits the current limit element, and To supply current to the load.

  That is, when the load is in a standby state, the electronic device provided with the inrush current limiting circuit relay control device, for example, has only a current necessary for the microcomputer, and the load current decreases. The load current has less voltage drop and power loss at the current limiting element or fixed resistor. Further, since only the current necessary for the standby state is passed through the current limiting element or the like, no current flows through the relay means, so that the life of the relay means is extended and the reliability of the device is improved. be able to. Moreover, since the said relay means can employ | adopt an inexpensive thing, the relay control apparatus for inrush current limiting circuits can be made inexpensive.

(Third invention)
A relay control device for an inrush current limiting circuit according to a third aspect of the present invention is provided with relay temperature detection means for detecting the temperature to which the relay means is exposed in the second aspect of the invention. The control means short-circuits the current limiting element when the load current detected by the current detection means is lower than a predetermined threshold value and the temperature detected by the relay temperature detection means is equal to or higher than a predetermined temperature. The relay contact is opened and current is controlled to be supplied to the load via the current limiting element. In the third invention, the operation of the relay means is stopped in consideration of the case where the load current is equal to or lower than the predetermined value and the case where the temperature in the vicinity of the relay means is equal to or higher than the predetermined temperature. That is, since the relay means considers the stop of the current flowing through the relay and the vicinity temperature, the life of the relay means can be extended and the reliability of the apparatus can be improved.

(Fourth invention)
The relay control device for an inrush current limiting circuit according to the fourth aspect of the present invention further includes relay drive time measuring means for measuring the drive time of the relay means in addition to the second or third aspect of the invention. The relay driving time measuring means measures the driving time of the relay means, and when the driving time has passed a predetermined time or more, the notifying means informs that maintenance is necessary. Therefore, the inrush current limiting circuit relay control device according to the fourth aspect of the invention can quickly take measures such as repair or replacement before failure.

  FIG. 1 is a schematic diagram for explaining an inrush current limiting circuit relay control apparatus according to an embodiment of the present invention. In FIG. 1, a power supply circuit includes an AC power supply 1, a power switch 2, a fuse 3, a current limiting element (PTC resistance element) 4, a current detection element 5, a bridge diode 6, and a smoothing electrolytic capacitor 7. Are connected as shown. In addition, a motor control circuit 8 and a load power supply circuit 9 are connected to the power supply circuit. Further, a relay contact 12 is connected to the current limiting element 4 in parallel.

  A motor 10 is connected to the motor control circuit 8. Further, the load power supply circuit 9 includes a relay coil 11 for turning on and off a relay contact 12 for short-circuiting the current limiting element 4, a temperature sensor 13 for monitoring a temperature in the vicinity of the relay coil 11, and the relay coil. 11 and a load control circuit 14 (microcomputer) for controlling the temperature sensor 13 are connected. The load control circuit 14 is connected to a state notification unit 15.

  When the power switch 2 is turned on, the load current passes through the fuse 3, the current limiting element 4, the current detecting element 5, and the bridge diode 6, and charges the smoothing electrolytic capacitor 7. Since the resistance value of the current flowing through the current limiting element 4 increases due to the characteristics when the power switch 2 is turned on, a sudden inrush current can be prevented, but the current necessary for the load cannot be passed. Therefore, the relay contact 12 connected in parallel to both ends of the current limiting element 4 detects the load current by the load control circuit 14 when the power switch 2 is turned on, and is turned on by the relay coil 11 to turn on the current limiting element 4. Short circuit.

  A temperature sensor 13 is provided in the vicinity of the relay coil 11 to constantly monitor the temperature in the vicinity of the relay coil 11. The load control circuit 14 always detects the load current by the current detection element 5, and when it is determined that the load current is small (for example, in a standby state), the load control circuit 14 stops supplying power to the relay coil 11, The relay contact 12 is opened, and current is supplied from the current limiting element 4 to the load. Since the load current in the standby state is small, power consumption due to the current flowing through the current limiting element 4 can be reduced. Thus, the relay coil 11 can extend its life because no current flows during the standby state.

  When the load control circuit 14 monitors the temperature in the vicinity of the relay coil 11 with the temperature sensor 13 and determines that the temperature is not related to the life of the relay coil 11, the detected current in the current detection element 5 is Even if it is small, power is supplied to the relay coil 11, the relay contact 12 is turned on, and the current limiting element 4 is short-circuited. As a result, the power consumption in the current limiting element 4 can be reduced and the efficiency can be improved.

  The load control circuit 14 performs ON / OFF control of the relay coil 11 and ambient temperature monitoring. For example, the load control circuit 14 measures the drive time of the relay coil 11 when a predetermined temperature is exceeded, and can notify the life of the relay coil 11 by the state notification means 15. Since the user can arrange maintenance, repair, replacement, etc. as soon as possible by the notification of the state notification means 15, inconvenience due to failure of the electronic device can be prevented in advance.

  FIG. 2 is a schematic block diagram for explaining an example of the load control circuit in FIG. In FIG. 2, the load control circuit 14 includes, for example, a current detection unit 211 that detects a load current, a load current threshold storage unit 212 that stores a load current threshold value in advance, and a current detected by the current detection unit 211. The load current determination means 213 compares the load current threshold stored in advance and determines whether or not to interrupt the current supplied to the relay coil, and the load current determination means 213 determines the current to the relay coil. Relay current interrupting means 214 for interrupting the current, relay means (contact) 215 for interrupting the current, temperature detecting means 216 comprising a temperature sensor for monitoring the temperature in the vicinity of the relay, and surroundings for reducing the life of the relay in advance Temperature threshold storage means 217 for storing a temperature threshold; temperature detected in the vicinity of the relay; and the temperature stored in advance Temperature determination means 218 for comparing and determining the temperature of the value storage means 217, relay drive time measurement means 219 for measuring the drive time of the relay means 215, relay drive time threshold storage means 220, and the measured relay drive A relay drive time determination means 221 for comparing and determining a time and a previously stored relay drive time threshold value, and a message, sound, or display when the relay is driven for a predetermined time or more by the relay drive time determination means 221 The relay driving time notifying means 222 for notifying by such means, and the control means 223 for controlling the respective blocks.

  When the load current determination unit 213 determines that the load current detected by the current detection unit 211 does not exceed a predetermined load current threshold, the load current determination unit 213 supplies the relay current in the relay unit 215 to the relay coil. To interrupt the current. As a result, the current limiting element is supplied with, for example, a load current in a standby state, but consumes less power because the current is small. Since the current is interrupted, the relay coil can extend its life.

  The temperature determination means 218 is a temperature that reduces the life of the relay coil by comparing the temperature in the vicinity of the relay coil detected by the temperature detection means 216 with a temperature threshold value stored in advance, and the current detection means When the current value detected by 211 is less than or equal to a certain value, the relay current interrupting unit 214 interrupts the current to the relay unit 215. When the relay driving time determination unit 221 determines that the driving time is equal to or greater than a predetermined time compared to the relay driving time threshold storage unit 220 and the relay driving time measurement unit 219 that measures the relay driving time, This is notified by the driving time notification means 222. The relay driving time notifying means 222 can take measures early as the user sees or listens.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example. The present invention can be modified in various ways without departing from the scope of the claims. For example, the block in this embodiment can be achieved by known or well-known technical means. In addition, the power source in this embodiment can be applied to known or well-known electronic devices.

It is the schematic for demonstrating the relay control apparatus for inrush current limiting circuits which is an Example of this invention. Example 1 FIG. 2 is a schematic block configuration diagram for explaining an example of a load control circuit in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... AC power source 2 ... Power switch 3 ... Fuse 4 ... Current limiting element (PTC resistance element)
DESCRIPTION OF SYMBOLS 5 ... Current detection element 6 ... Bridge diode 7 ... Smoothing electrolytic capacitor 8 ... Motor control circuit 9 ... Power supply circuit for load 10 ... Motor 11 ... Relay coil 12 ... Relay contact 13 ... Temperature sensor 14 ... Load control circuit (microcomputer)
DESCRIPTION OF SYMBOLS 15 ... State notification means 211 ... Current detection means 212 ... Load current threshold storage means 213 ... Load current judgment means 214 ... Relay current interruption means 215 ... Relay means 216 ... Temperature Detection means 217... Temperature threshold storage means 218... Temperature determination means 219... Relay drive time measurement means 220... Relay drive time threshold storage means 221. Driving time notification means 223... Control means

Claims (4)

When closing the power switch that turns on or off the AC voltage, a current limiting element is connected in series with the circuit to reduce the inrush current that flows through the circuit between the power switch and the power rectifier. In the relay control method for an inrush current limiting circuit in which the current limiting element is short-circuited by the relay contact after passing the inrush current,
A relay control method for an inrush current limiting circuit, wherein a load current is detected, and when the load current is lower than a predetermined value, the relay is turned off and a current is supplied to the load via the current limiting element. When closing the power switch that turns on or off the AC voltage, a current limiting element is connected in series with the circuit to reduce the inrush current that flows through the circuit between the power switch and the power rectifier. In the relay control device for the inrush current limiting circuit that short-circuits the current limiting element by the relay contact after passing the inrush current,
Current detection means for detecting a load current;
A relay contact for short-circuiting the current limiting element and a relay means for ON-OFF the relay contact;
Load current threshold storage means for storing in advance a load current threshold that becomes low resistance when the load current flows through the current limiting element;
Load current determination means for determining that the load current detected by the current detection means is lower than the load current threshold stored in the load current threshold storage means stored in advance;
When the load current determining means determines that the load current value is equal to or less than a predetermined current value, the contact in the relay means that short-circuits the current limiting element is opened, and the load is passed through the current limiting element. Control means for controlling to supply current;
A relay control device for an inrush current limiting circuit.   A relay temperature detecting means for detecting a temperature to which the relay means is exposed; a load current detected by the current detecting means is lower than a predetermined threshold value; and a temperature detected by the relay temperature detecting means The control is performed so that a current is supplied to a load through the current limiting element by opening a relay contact that short-circuits the current limiting element when the temperature is equal to or higher than a predetermined temperature. The relay control device for the inrush current limiting circuit described.   A relay drive time measuring means for measuring the drive time of the relay means is provided, and the relay drive time measuring means informs that maintenance is required when the drive time of the relay means has exceeded a certain time. The relay control device for an inrush current limiting circuit according to claim 2 or 3, further comprising a notification unit.

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