JP2013073824A - Power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply unit which, although compact and available at low cost, detects sticking of a relay and, even when a relay is actually stuck, secures sufficient safety.SOLUTION: A power supply unit 1A comprises a main power supply 3 which receives electricity supply from an input power supply 2 via a pair of power supply lines L1 and L2, transfer contact type relays TRL1 and TRL2 which are disposed on the respective power supply lines, a controller 4, and a detection circuit 5A. A common contact c of each relay is connected to the input power supply, and each normally-closed contact a is connected to the main power supply. In each relay, the common contact and the normally-closed contact are connected, and the common contact and a normally-open contact are connected by a relay on/off signal sent from the controller, respectively. The detection circuit, which is connected between the normally-open contacts, outputs a detection signal on the basis of a voltage or a current fed from the input power supply. When no detection signal is output while a relay-off signal is being sent, the controller determines that the relay is stuck.

Description

  The present invention relates to a power supply device.

Conventionally, for example, a power supply device described in Patent Literature 1 is known as a power supply device with reduced standby power.
As shown in FIG. 4, the power supply device 1 </ b> X includes a main power supply 3, relays RL <b> 1 and RL <b> 2, a control unit 4 </ b> X, and a standby power supply 6.

The main power supply 3 receives power supply from the input power supply 2 through a pair of power supply lines L1 and L2, and drives main equipment (not shown).
The relays RL1 and RL2 are interposed in the pair of power supply lines L1 and L2, respectively, and have one contact connected to the input power supply 2 and the other contact connected to the main power supply 3. The relays RL1 and RL2 are simultaneously turned on / off by a relay on / off signal (relay drive signal) sent from the control unit 4X to the relay drive coil (induction coil).
The control unit 4X controls each operation of the relays RL1 and RL2 and the main power source 3.
The standby power supply 6 supplies power to a minimum necessary circuit or the like (for example, the control unit 4X) during standby (when the main power supply 3 is not driving the device).

According to the power supply device 1X, the control unit 4X sends a relay-off signal and puts the relays RL1 and RL2 into a non-conductive state during standby, whereby the main power supply 3 is electrically disconnected from the input power supply 2 and the main power supply The power consumption at 3 becomes zero, and the standby power is reduced.
However, in this power supply device 1X, if welding occurs in one of the relays RL1 and RL2 due to some cause (for example, overcurrent), the main power supply 3 is connected to the input power supply 2 even if the control unit 4X sends a relay off signal. In some cases, it was not possible to be electrically disconnected from the door, and its safety was not sufficiently ensured.
Specifically, when both relays RL1 and RL2 are welded at a time, the main power source 3 cannot be turned off, and a failure can be detected. However, when only one of the relays RL1 and RL2 is welded, it is used without detecting the welding of the relay on the live side by opening / closing the neutral side relay of the polarity (live / neutral) of the input power supply 2 Therefore, safety cannot be secured sufficiently. That is, when opening and closing with only one relay, it is necessary to open and close the relay on the live side, but when the input power source 2 is a two-pole outlet of AC 100 [V], the outlet is not particularly polar. If there is no polarity in the plug of the power cord connected to the outlet, it is unclear which side of the relays RL1 and RL2 will be live, so if only one of the relays RL1 and RL2 is welded The safety was not ensured enough.

By the way, in Chapter 2 “Equipment Measures Necessary for Interconnection” of the grid connection regulation “JEAC9701” of the NEC Association, for example, “gate block by an open signal using one mechanical switching point and internal contactor” (The operation of the main power supply etc. is stopped) ”, and facility measures for safety in the event of an abnormality in the power supply device are defined. This rule is only for power supply devices related to photovoltaic power generation and power storage, but it goes without saying that the same facility measures are required for other general power supply devices.
For this reason, in recent years, there has been a demand for a power supply apparatus that detects welding of a relay and secures sufficient safety by stopping the operation of the main power supply even at the time of welding.

For example, a power supply device described in Patent Document 2 is known as a power supply device that can detect the welding of the relay.
As shown in FIG. 5, the power supply device 1Y includes relays RL1 and RL2, an auxiliary relay RL3, and a detection circuit (abnormality detection circuit) 5Y. For simplification of explanation, the auxiliary relay and detection circuit arranged on the relay RL2 side are omitted in FIG.

The auxiliary relay RL3 is disposed on the relay RL1 side and has an auxiliary contact. The auxiliary relay RL3 enters a conductive / non-conductive state in conjunction with the relays RL1 and RL2 based on a relay on / off signal sent from the control unit 4Y to the relay drive coil (induction coil).
The detection circuit 5Y includes a resistor RY and a voltage detection unit 8. One side of the resistor RY is connected to a low-voltage power supply (not shown), and the other side is connected to one contact of the voltage detector 8 and the auxiliary relay RL3. The other contact of the auxiliary relay RL3 is connected to GND.

In this power supply device 1Y, when it is normal (when the relays RL1 and RL2 are not welded), when the control unit 4Y sends a relay on signal to the relay drive coil, the relays RL1 and RL2 and the auxiliary relay RL3 are in a conductive state, and the low The voltage power supply is connected to GND via the resistor RY, and an L level detection signal is output from the voltage detection unit 8 of the detection circuit 5Y. On the other hand, when the control unit 4Y sends a relay-off signal to the relay drive coil, the relays RL1 and RL2 and the auxiliary relay RL3 are in a non-conductive state, and the voltage detection unit 8 outputs an H level detection signal.
On the other hand, the power supply device 1Y has a structure in which the auxiliary relay RL3 cannot be opened / closed when there is an abnormality in which welding has occurred in one or both of the relays RL1 and RL2. For this reason, even when the control unit 4Y sends a relay-off signal at the time of abnormality, all of the relays RL1, RL2 and the auxiliary relay RL3 are not in a non-conductive state, so that no detection signal is output from the detection circuit 5Y.
Therefore, according to the power supply device 1Y, based on the detection signal from the detection circuit 5Y in the conductive / non-conductive state of the auxiliary relay RL3 interlocked with the relays RL1 and RL2, and the relay drive signal from the control unit 4Y, Whether or not RL1 and RL2 are welded can be detected.

  However, in this power supply device 1Y, the distance between the secondary side component consisting of the auxiliary relay RL3 and the relay drive coil and the primary side component consisting of the relays RL1 and RL2 is set between the primary side component and the secondary side component. It is necessary to ensure enough to satisfy the safety standards applied to For this reason, compared with the power supply device using the relay which does not have an auxiliary contact, the point which becomes large in size and expensiveness has been a problem.

JP 2005-295632 A JP 2005-295698 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply device that is small and low-cost, and that detects welding of a relay and ensures sufficient safety even during the welding.

In order to solve the above problems, the present invention provides (1) a main power supply that receives power supply from an input power supply via a pair of power supply lines, and a transfer contact type relay disposed on each of the pair of power supply lines. A normally open contact, a normally closed contact connected to the main power source, and a common contact connected to the input power source, respectively, and the common contact and the normal contact by a relay-on signal sent from a control unit. A relay connected to the common contact and the normally-open contact by a relay-off signal sent from the control unit; and a connection between the normally-open contact of each relay; A detection circuit that outputs a detection signal based on the voltage or current supplied from the control circuit, wherein the control unit sends the relay-off signal to the relay. If there is no output of the detection signal from the serial detection circuit, in which a power supply device and judging a welding of the relay occurs.
According to this configuration, the transfer contact type relay is disposed on each of the pair of power supply lines between the input power source and the main power source, and the connection state of each contact of the relay is determined by the relay on signal and the relay off signal from the control unit. When the switching is performed and at least one of the relays is welded, the control unit is connected to the relay by utilizing the fact that the detection circuit is not connected to the input power supply (the detection signal is not output from the detection circuit). Based on the relay-off signal sent and the detection signal from the detection circuit, the presence or absence of relay welding is determined. Therefore, by using a transfer contact type relay, an auxiliary relay having an auxiliary contact can be made unnecessary (more specifically, the secondary side component is a relay drive coil compared to the conventional auxiliary relay having an auxiliary contact). As a result, all parts other than the relay drive coil can be used as primary parts, and the distance between the primary parts and the secondary parts can be further shortened). Therefore, it is possible to realize a power supply device that detects relay welding at a much smaller size and at a lower cost.

In the configuration (1), (2) when the control unit determines that the relay is welded, the control unit sends a main power supply stop signal for stopping the operation of the main power supply to the main power supply. Is preferred.
According to this configuration, even if the input power supply and the main power supply are connected when the relay is welded, the control unit sends a main power supply stop signal to stop the operation of the main power supply. Can be realized.

Further, in the above configuration (1) or (2), (3) the detection circuit is configured such that the detection resistor connected between the normally open contacts of each relay and the voltage between both ends of the detection resistor. And a voltage detector that outputs the detection signal based on the above.
According to this configuration, since the detection circuit includes only the detection resistor and the voltage detection unit, a power supply device having an extremely simple configuration can be realized.

In the configuration (1) or (2), (4) the detection signal is output based on (4) a light emitting element connected between the normally open contacts of the relays and light emission caused by a current flowing through the light emitting element. It is preferable to consist of a light receiving element.
According to this configuration, the detection circuit includes only the light emitting element and the light receiving element, and the detection signal using light emission is generally not easily affected by noise. It is possible to realize a power supply device that can determine welding.

  ADVANTAGE OF THE INVENTION According to this invention, while being small and low-cost, while detecting the welding of a relay, the power supply device which ensured sufficient safety | security at the time of the welding can be provided.

It is a block diagram which shows the power supply device which concerns on 1st Example of this invention. It is a graph which shows operation | movement of each part of a power supply device, (a) is a time waveform of a relay drive signal (relay on / off signal), (b) is a time waveform of a detection signal, (c) is a time waveform of a main power supply stop signal. Indicates. It is a block diagram which shows the power supply device which concerns on 2nd Example of this invention. It is a block diagram which shows the conventional power supply device. It is a block diagram which shows the other conventional power supply device.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a power supply device according to a first embodiment of the present invention.
The power supply device 1A includes a main power supply 3, transfer contact type relays TRL1 and TRL2, a control unit 4, and a detection circuit 5A.

  The main power supply 3 receives power supply from the input power supply 2 through a pair of power supply lines L1 and L2, and drives main equipment (not shown).

The transfer contact type relays TRL1 and TRL2 are interposed in a pair of power supply lines L1 and L2, respectively, and have a normally closed contact a, a normally open contact b, and a common contact c. Each normally closed contact a is connected to the main power supply 3. Each normally open contact b is connected to a detection circuit 5A described later. Each common contact c is connected to the input power source 2.
In these relays TRL1 and TRL2, the connection states of the contacts a, b, and c are switched by a relay on / off signal (relay driving signal) sent from the control unit 4 to the relay driving coil (induction coil). . That is, the common contact c and the normally closed contact a are connected by the relay ON signal, and the common contact c and the normally open contact b are connected by the relay OFF signal.
Note that the relay on / off signal is sent from the control unit 4 to the relays TRL1 and TRL2 via a relay drive circuit (not shown) including transistors and the like.

The control unit 4 controls each operation of the relays TRL1, TRL2 and the main power source 3.
Moreover, the control part 4 determines the presence or absence of welding of this relay based on the relay-off signal sent to relay TRL1 and TRL2, and the detection signal from 5 A of detection circuits which are mentioned later. The control unit 4 determines that the relay is welded when no detection signal is output even though the relay-off signal is transmitted.
Further, when it is determined that the relay is welded, the controller 4 sends a main power supply stop signal for stopping the operation of the main power supply 3 to the main power supply 3.

The detection circuit 5 </ b> A is configured to output a detection signal based on the voltage or current supplied from the input power supply 2 to the control unit 4. In this embodiment, the detection circuit 5A includes a detection resistor RA and a voltage detection unit 7.
Both ends of the detection resistor RA are connected between the normally open contacts b of the relays TRL1 and TRL2.
The voltage detection unit 7 is connected in parallel to the detection resistor RA, and outputs a detection signal based on the voltage across the detection resistor RA. For example, the voltage detector 7 outputs a detection signal when the voltage V across the detection resistor RA is equal to or higher than the reference voltage Vth, and does not output a detection signal when the voltage V is lower than the reference voltage Vth. Yes.

  Next, the operation of the power supply apparatus 1A of the present invention will be briefly described below with reference to FIG.

First, when the relays TRL1 and TRL2 are not welded normally, when the control unit 4 sends a relay-off signal to the relays TRL1 and TRL2 during the period from the time t1 to the time t2, as shown in FIG. The normally closed contact a becomes non-conductive, the main power source 3 is electrically disconnected from the input power source 2, and the common contacts c and normally open contacts b become conductive, so that the input power source 2 and the detection circuit 5A is connected. As a result, a current from the input power supply 2 flows through the detection resistor RA, the voltage V across the detection resistor RA becomes equal to or higher than the reference voltage Vth, and the voltage detection unit 7 outputs a detection signal.
During this period, since the relay-off signal and the detection signal are output at the same time, the control unit 4 determines that the relays TRL1 and TRL2 are not welded.
When the control unit 4 sends a relay-on signal to the relays TRL1 and TRL2 during the period of time t2 to t3, the common contact c and the normally closed contact a of each relay are in a conductive state, and the main power supply 3 is connected to the input power supply 2. In addition to being connected, each common contact c and normally open contact b become non-conductive, and the detection circuit 5A is disconnected from the input power source 2. As a result, no current flows through the detection resistor RA, the voltage V across the detection resistor RA becomes zero and becomes less than the reference voltage Vth, and the voltage detector 7 does not output a detection signal.

Next, at the time of an abnormality in which welding occurs in at least one of the relays TRL1, TRL2, even if the control unit 4 sends a relay-off signal to the relays TRL1, TRL2 during the period from time t3 to t4, each relay Since at least one of the common contact c and the normally open contact b is in a non-conductive state, the detection circuit 5A is not electrically connected to the input power source 2. For this reason, no current flows through the detection resistor RA, and the voltage detector 7 does not output a detection signal.
That is, during this period, the control unit 4 determines that welding has occurred in at least one of the relays TRL1 and TRL2 because no detection signal is output even though the control unit 4 sends a relay-off signal. To do.
In addition, when welding occurs only in one of the relays TRL1 and TRL2, power is not supplied to the main power supply 3 and the main power supply 3 stops operating, but welding occurs in both the relays TRL1 and TRL2. If so, the control unit 4 sends a main power supply stop signal for stopping the operation of the main power supply 3 to the main power supply 3. Thereby, the operation of the main power supply 3 is stopped.
Further, when the control unit 4 once sends a main power supply stop signal to the main power supply 3 at time t3, the signal is output by a latch circuit (not shown) disposed between the control unit 4 and the main power supply 3, for example. Is held after time t3 (it is kept after time t4 when the relay-off signal is turned off). The signal is reset by a reset signal from the control unit 4.

According to this power supply device 1A, the transfer contact type relays TRL1 and TRL2 are interposed in each of the pair of power supply lines L1 and L2 between the input power supply 2 and the main power supply 3, and each contact a, b of the relay is provided. , C are switched by a relay-on signal and a relay-off signal from the control unit 4, and when the welding occurs in at least one of the relays, the detection circuit 5A is not connected to the input power source 2 (the detection circuit). Based on the relay-off signal sent to the relays TRL1 and TRL2 and the detection signal from the detection circuit 5A, the control unit 4 determines whether or not the relay is welded. Is configured to do.
Therefore, the use of the transfer contact type relays TRL1 and TRL2 eliminates the need for the conventional auxiliary relay having the auxiliary contact (more specifically, the secondary side of the auxiliary relay having the conventional auxiliary contact). Since the parts are only relay drive coils, all parts other than the relay drive coils can be used as primary parts, and the distance between the primary parts and the secondary parts can be further shortened). The welding of the relay can be detected at a much smaller size and at a lower cost as compared with the power supply apparatus.
Further, even when the input power supply 2 and the main power supply 3 are connected when the relays TRL1 and TRL2 are welded, the control unit 4 sends a main power supply stop signal to stop the main power supply 3, thereby ensuring sufficient safety. be able to.
Furthermore, since the detection circuit 5A comprises only the detection resistor RA and the voltage detection unit 7, a power supply device having a very simple configuration can be realized.

(Second embodiment)
The power supply device 1B of the second embodiment is only different from the power supply device 1A of the first embodiment in the configuration of the detection circuit. Therefore, only this point will be described.

The detection circuit 5B includes a light emitting element and a light receiving element, and the light receiving element outputs a detection signal based on light emission caused by a current flowing through the light emitting element.
As shown in FIG. 3, the detection circuit 5B includes, for example, a photocoupler PC including a light emitting diode (light emitting element) D and a phototransistor (light receiving element) Tr. The light emitting diode D is connected between the normally open contacts b of the relays TRL1 and TRL2. In addition, the phototransistor Tr outputs a detection signal to the control unit 4 based on light emission due to a current flowing through the light emitting diode D.
Therefore, according to this power supply device 1B, when the detection circuit 5B is connected to the input power supply 2, the light emitting diode D emits light and the detection signal is output to the control unit 4. Therefore, the power supply device 1A of the first embodiment. In the same manner as described above, it is possible to detect the welding of the relay and to ensure sufficient safety even during the welding while being small and low cost.
In addition, according to the power supply device 1B, the detection circuit 5B includes only the light-emitting diode D and the phototransistor Tr, and the detection signal using light emission is generally hardly affected by noise. Thus, the welding of the relay can be determined more accurately.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments.
For example, the detection circuits 5A and 5B are merely examples. The detection circuit may be configured to output a detection signal when electrically connected to the input power supply.

1A, 1B, 1X, 1Y Power supply 2 Input power supply 3 Main power supply 4, 4X, 4Y Control section 5A, 5B, 5Y Detection circuit 6 Standby power supply 7, 8 Voltage detection section a Normally closed contact b Normally open contact c Common contact D Light-emitting diode PC Photocoupler RA Detection resistance RY Resistance RL1, RL2 Relay RL3 Auxiliary relay TRL1, TRL2 Transfer contact type relay Tr Phototransistor

Claims (4)

A main power source that receives power from an input power source via a pair of power lines;
A transfer contact type relay interposed in each of the pair of power supply lines, each having a normally open contact, a normally closed contact connected to the main power supply, and a common contact connected to the input power supply, respectively. And the common contact and the normally closed contact are connected by a relay on signal sent from the control unit, and the common contact and the normally open contact are connected by a relay off signal sent from the control unit. Relay,
A detection circuit connected between the normally open contacts of each of the relays and outputting a detection signal based on a voltage or current supplied from the input power supply,
The control unit determines that the relay is welded when the detection signal is not output from the detection circuit even though the relay off signal is transmitted to the relay. Power supply.   2. The power supply device according to claim 1, wherein the control unit sends a main power supply stop signal for stopping the operation of the main power supply to the main power supply when it is determined that the relay is welded. .   The detection circuit includes a detection resistor connected between the normally open contacts of each relay, and a voltage detection unit that outputs the detection signal based on the amount of voltage between both ends of the detection resistor. The power supply device according to claim 1, wherein:   The detection circuit includes: a light emitting element connected between the normally open contacts of each relay; and a light receiving element that outputs the detection signal based on light emission by a current flowing through the light emitting element. Item 3. The power supply device according to Item 1 or 2.

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