JP2012181029A - Power supply control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply control device in which power supply to an electric device may be stopped when the electric device is not grounded or is connected to a power source with incorrect polarity and which is minimally deteriorated over time.SOLUTION: A power supply control device 1 comprises a pair of transformers 2a and 2b different from each other in turn ratios of primary coils 21 and secondary coils 22. A primary coil group 210 is connected to power supply lines 40 and 41. A point between a pair of primary coils 21a and 21b is connected to a ground line 42 of an electric device 4. A secondary coil group 220 is connected to a control circuit 3 controlling power supply to the electric device 4. The control circuit 3 detects, in accordance with an induced voltage caused in the secondary coil group 220, whether or not the electric device 4 is connected to an AC power supply 7 (commercial power supply) with incorrect polarity and whether or not the electric device 4 is grounded.

Description

  The present invention relates to a power supply control device that controls power supply to an electrical device that requires ground connection.

  2. Description of the Related Art Conventionally, there is known a power supply control device that detects whether or not an electrical device is grounded and stops power feeding to the electrical device when the ground is not grounded (see Patent Documents 1 and 2 below). .

  As shown in FIG. 11, the power supply control device includes, for example, a relay 9, a diode 971 and a voltage dividing resistor 92 connected in series, a photocoupler 97, and a transistor 98. The relay 9 is provided on the power supply lines 940 and 941 of the electric device 94. The voltage dividing resistor 92 and the diode 971 are connected between the hot power supply line 940 and the ground line 96 of the electric device 94. The photocoupler 97 includes a light emitting diode 970 connected between the voltage dividing point of the voltage dividing resistor 92 and the cold power supply line 941. The transistor 98 amplifies the secondary side voltage of the photocoupler 97.

When the ground wire 96 is grounded, the light emitting diode 970 does not emit light, the transistor 98 is turned on, and a current flows through the relay coil 99. As a result, the relay 9 is connected and power is supplied to the electric device 94.
When the ground wire 96 is not grounded, the light emitting diode 970 emits light, the transistor 98 is turned off, and no current flows through the relay coil 99. As a result, the relay 9 is cut off and the power supply to the electric device 94 is stopped.

Japanese Patent Laid-Open No. 10-116653 JP-A-8-166420

  However, the conventional power supply control device 90 has a problem that the light emitting diode 970 deteriorates with time and the light emission amount decreases. Therefore, when the power supply control device 90 is used for a long period of time, the photocoupler 97 does not operate normally, and the relay 9 is connected to the electric device 94 even though it is not grounded. Therefore, a power supply control device that is less likely to deteriorate over time has been desired.

  The commercial power supply 91 includes a cold terminal C that is grounded and a hot terminal H that is not grounded. If the power plug 93 is connected to the outlet 910 of the commercial power supply 91 with the wrong polarity, the current I may flow from the hot terminal H to the ground E through the ground wire 96. Therefore, a power supply control device that can stop power supply to the electric device 94 when the power plug 93 is connected with a wrong polarity has been desired.

  An object of the present invention is to provide a power supply control device that can stop power supply to an electrical device and is less likely to deteriorate over time when the electrical device is not connected to the ground or is connected to a power source with a wrong polarity. .

The present invention is a power supply control device for controlling power supply to an electrical device that requires ground connection,
A pair of transformers having different turns ratios of the primary coil and the secondary coil,
The primary coils of the pair of transformers are connected in series to form a primary coil group, and the secondary coils are connected in series to form a secondary coil group,
The primary coil group is connected in parallel with the electrical device to the power line of the electrical device,
Between the pair of primary coils is connected to the ground wire of the electrical equipment,
The secondary coil group is connected to a control circuit that controls power supply to the electrical equipment,
In accordance with the induced voltage generated in the secondary coil group, the control circuit determines whether or not the electric device is connected with an incorrect polarity to an AC power source having one terminal connected to the ground. It is detected whether or not the electric device is connected to the earth, and when the electric device is connected with the wrong polarity or when the electric device is not connected to the earth, the power supply to the electric device is stopped. The power supply control device is characterized in that it is configured (claim 1).

  According to the above power supply control device, the difference in induced voltage generated in the secondary coil group between the state in which the electrical equipment is grounded and connected to the power supply without making a mistake in polarity (normal use state) and the other state Can detect the control circuit. Therefore, when the ground connection is not established or when the polarity is wrongly connected to the power source, the power supply to the electric device can be stopped.

That is, for example, when power is supplied using a single-phase two-wire commercial power source, in the normal use state, the primary current passes from only one primary coil of the pair of primary coils from the hot terminal of the commercial power source. It flows to the ground, and no primary current flows to the other primary coil.
Also, when the electrical equipment is grounded and connected to the power supply with the wrong polarity (polarity mismatch state), the primary current flows from the hot terminal to the ground through only the other primary coil, and flows to one primary coil. The primary current does not flow.
Further, when the electrical device is not connected to the ground (non-grounded state), the primary current flows from the hot terminal to the cold terminal through both primary coils.

  The pair of transformers have different turns ratios of the primary coil and the secondary coil, so that the primary current flows only in one primary coil, the primary current flows only in the other primary coil, and both primary coils. The induced voltage generated in the secondary coil group changes depending on when the primary current flows. Therefore, the control circuit can detect whether the electric device is in a normal use state, a polarity mismatch state, or a non-grounded state by detecting the induced voltage. Therefore, when the control circuit detects that the polarity does not match or is not grounded, power supply to the electrical device can be stopped.

  In addition, unlike a light emitting element, a transformer is a component that is unlikely to deteriorate over time, so that even if the power supply control device is used for a long period of time, it is unlikely to malfunction.

  As described above, according to the present invention, it is possible to provide a power supply control device that can stop power supply to an electrical device and is less likely to deteriorate over time when the electrical device is not connected to ground or is connected to a power supply with a wrong polarity. can do.

1 is a circuit diagram of a power feeding control device in Embodiment 1. FIG. The circuit diagram of the electric power feeding control apparatus in the normal use state in Example 1. FIG. The circuit diagram of the electric power feeding control apparatus at the time of reversing the polarity of the power plug in Example 1, and connecting to an outlet. The circuit diagram of the electric power feeding control apparatus in case the electric equipment in Example 1 is not earth-connected. The circuit diagram of the electric power feeding control apparatus in Example 2. FIG. The circuit diagram of the electric power feeding control apparatus in the normal use state in Example 2. FIG. The circuit diagram of the electric power feeding control apparatus at the time of connecting in earth | ground in Example 2 and connecting the H2 terminal of a power plug accidentally to the cold terminal of an outlet socket. The circuit diagram of the electric power feeding control apparatus in the case of earth-connecting in Example 2 and when the H1 terminal of a power plug is accidentally connected to the cold terminal of the outlet. The circuit diagram of the electric power feeding control apparatus in the case of being not earth-connected in Example 2. FIG. The circuit diagram of the electric power feeding control apparatus in Example 2 when the H2 terminal of a power plug is accidentally connected to the cold terminal of an electric outlet, and it is not earth-connected. The circuit diagram of the electric power feeding control apparatus in a prior art example.

A preferred embodiment of the present invention described above will be described.
The electric device that the power supply control device controls the power supply is, for example, a charger for charging a battery mounted on an electric vehicle or a hybrid vehicle using a commercial power supply (AC power supply).

In the power supply control device, one terminal of the secondary coil group is connected to the anode terminal of the rectifier diode, the cathode terminal of the rectifier diode is connected to the control circuit, and the other terminal of the secondary coil group is It is preferable that a capacitor and a resistor are connected in parallel between the cathode terminal of the rectifier diode and the other terminal, which are grounded.
In this case, since only one terminal of the secondary coil group can be connected to the control circuit, the number of wires required for connection is smaller than when both terminals of the secondary coil group are connected to the control circuit. It is possible to reduce the number of parts. Therefore, the manufacturing cost of the power supply control device can be reduced.

Example 1
A power supply control device according to an embodiment of the present invention will be described with reference to FIGS.
The power supply control device 1 of this example is a device that controls power supply to the electrical equipment 4 that requires ground connection. The power supply control device 1 includes a pair of transformers 2 (2a, 2b) in which the turns ratio between the primary coil 21 and the secondary coil 22 is different from each other.
The primary coils 21 a and 21 b of the pair of transformers 2 are connected in series to form a primary coil group 210. Further, the secondary coils 22 a and 22 b are connected in series to form a secondary coil group 220.

  The primary coil group 210 is connected to the power supply lines 40 and 41 of the electric device 4 in parallel with the electric device 4. Between the pair of primary coils 21 a and 21 b, the ground wire 42 of the electric device 4 is connected. The secondary coil group 220 is connected to a control circuit 3 that controls power supply to the electrical device 4.

  According to the induced voltage generated in the secondary coil group 220, the control circuit 3 makes the electric device 4 have the wrong polarity with respect to the AC power supply 7 (commercial power supply) in which one terminal (cold terminal C) is grounded. And whether or not the electrical device 4 is grounded is detected. The control circuit 3 is configured to stop the power supply to the electrical device 4 when the electrical device 4 is connected with a wrong polarity or is not grounded.

  The electric device 4 is a charger for charging a battery (not shown) mounted on a vehicle such as an electric vehicle or a hybrid vehicle using an AC power source 7. A ground wire 42 is attached to the housing 400 of the electric device 4. By connecting the connection terminal 420 of the ground wire 4 to the connected terminal 140 on the ground 14 side, the electrical device 4 is grounded.

  In addition, power lines 40 and 41 for power supply are connected to the electric device 4. A power plug 6 is provided at one end of the power lines 40 and 41.

  The AC power source 7 is a single-phase two-wire commercial power source. The AC power source 7 includes a cold terminal C that is grounded and a hot terminal H that is not grounded. By inserting the power plug 6 into the outlet 5 of the AC power supply 7, power is supplied to the electric device 4.

  The power lines 40 and 41 include a power line 40 on the hot terminal H side and a power line 41 on the cold terminal C side. One terminal 210 a of the primary coil group 210 is connected to the power line 40 on the hot terminal H side at the connection portion 48 by the wiring 28. The other terminal 210 b of the primary coil group 210 is connected to the power line 41 on the cold terminal C side at the connection portion 49 by the wiring 29.

  Relays 11 are provided in the power supply lines 40 and 41, respectively. When the relays 11a and 11b are turned on, power is supplied from the AC power source 7 to the electric device 4, and when the relays 11a and 11b are turned off, power supply to the electric device 4 is stopped. Control of the relay 11 is performed by the control circuit 3. The relays 11a and 11b are provided in the power supply lines 40 and 41 at positions closer to the electrical device 4 than the connection portions 48 and 49, respectively.

  As described above, the pair of transformers 2a and 2b have different turns ratios of the primary coil 21 and the secondary coil 22, respectively. The intermediate point 13 between the primary coil 21 a and the other primary coil 21 b of the primary coil group 210 and the ground wire 42 are connected by a connection line 130.

  One terminal 220 a of the secondary coil group 220 is connected to the anode terminal of the rectifier diode 12. The cathode terminal of the rectifier diode 12 is connected to the control circuit 3. The control circuit 3 is connected to relay coils (not shown) of the relays 11a and 11b. The other terminal 220 b of the secondary coil group 220 is connected to the control ground 27. The capacitor 10 and the resistor R are connected in parallel between the cathode terminal of the rectifier diode 12 and the other terminal 220b of the secondary coil group 220, respectively.

  FIG. 2 shows a path through which the primary current I and the secondary current i flow when the electric device 4 is connected to the AC power source 7 without mistake in polarity and is connected to the ground (normal use state). Thus, the power plug 6 is inserted into the outlet 5 and the ground wire 42 is grounded so that the hot power line 40 is connected to the hot terminal H and the cold power line 41 is connected to the cold terminal C. 14, the primary current I flows from the hot terminal H to the ground 14 through the power supply line 40, the wiring 28, one primary coil 21 a, and the connection line 130. Since the other primary coil 21b becomes a resistance against the primary current I (alternating current), the primary current I does not flow through the other primary coil 21b.

  When the primary current I flows through one primary coil 21a, an induced voltage is generated in one secondary coil 22a. The induced voltage is half-wave rectified by the rectifier diode 12 and smoothed by the capacitor 10. As a result, a DC voltage is applied to the connection part 30 of the control circuit 3.

  As shown in FIG. 3, when the electric device 4 is connected to the AC power source 7 with the wrong polarity and is connected to the ground (polarity mismatch state), the primary current I flows only through the other primary coil 21b. . That is, when the hot-side power line 40 is connected to the cold terminal C, the power plug 6 is inserted so that the cold-side power line 41 is connected to the hot terminal H, and the earth wire 42 is connected to the ground 14, A primary current I flows from the hot terminal H to the ground 14 through the power supply line 41, the wiring 29, the other primary coil 21 b, and the connection line 130. Since one primary coil 21a becomes a resistance with respect to the primary current I (alternating current), the primary current I does not flow into one primary coil 21a.

  In the normal use state, the primary current I flows only in one primary coil 21a, whereas in the polarity mismatch state, the primary current I flows only in the other primary coil 21b. As described above, the transformers 2a and 2b have different turns ratios of the primary coil 21 and the secondary coil 22. Therefore, in the polarity mismatch state, an induced voltage different from that in the normal use state is generated in the secondary coil group 220. Then, a voltage different from the normal use state is applied to the connection part 30 of the control circuit 3.

  As shown in FIG. 4, when the ground wire 42 is not connected to the ground 14 (non-grounded state), the primary current I is supplied from the hot terminal H to the hot power line 40, the wiring 28, and one primary coil 21a. , Flows through the other primary coil 21b, the wiring 29, and the power line 41 on the cold side to the cold terminal C. That is, the primary current I flows through both primary coils 21a and 21b of the primary coil group 210.

  In FIG. 4, the power plug 6 is connected without making a mistake in polarity. However, when the polarity is wrong, the primary current I flows through both the primary coils 21 a and 21 b in the same manner as described above.

  Thus, since the primary current I flows through both primary coils 21a and 21b in the non-grounded state, the secondary coil group 220 has a normal use state (see FIG. 2) and a polarity mismatch state (see FIG. 3). Produces different induced voltages. Therefore, a voltage different from the normal use state and the polarity mismatch state is applied to the connection part 30 of the control circuit 3.

For example, in one transformer 2a, the turns ratio N1 / N2 = 34 of the number of turns N1 of the primary coil 21a and the number of turns N2 of the secondary coil 22a is set to 34, and the number of turns N3 of the primary coil 21b and the secondary coil 22b of the other transformer 2b. When the turn ratio N3 / N4 = 120, the capacitance of the capacitor 10 is 10 μF, and the resistance R is 10 MΩ, the voltage applied to the connection portion 30 is 4.16 V in a normal use state (see FIG. 2). It becomes. Further, it is 1.18V in the polarity mismatch state (see FIG. 3), and 1.84V in the non-ground state.
Therefore, for example, if the relay 11 is connected only when the voltage applied to the connection unit 30 is 3.0 V or more, and the relay 11 is disconnected when the voltage is less than 3.0 V, the normal use state is achieved Only in this case, it is possible to supply power to the electric device 4.

The effect of this example will be described.
According to the power supply control device 1 of the present example, the secondary coil group 220 generates a state in which the electrical device 4 is grounded and connected to the power supply without making a mistake in polarity (normal use state), and other states. The control circuit 3 can detect the difference in induced voltage. Therefore, when the ground connection is not established (non-grounded state) or when the polarity is wrongly connected to the power source (polarity mismatch state), the power supply to the electrical device 4 can be stopped.

  As a result, power is supplied to the electric device 4 in a state where it is not grounded (non-grounded), an electric shock occurs, or the power plug 6 is connected with the wrong polarity (polarity mismatch state), and a large ground current is grounded. It is possible to prevent a malfunction that flows in the line 42.

  In addition, unlike the light emitting element, the transformer 2 is a component that does not easily deteriorate over time, and therefore, it is unlikely to malfunction even when the power supply control device 1 is used for a long period of time.

  In this example, as shown in FIG. 1, one terminal 220 a of the secondary coil group 220 is connected to the anode terminal of the rectifier diode 12, and the cathode terminal of the rectifier diode 12 is connected to the control circuit 3. The other terminal 220b of the secondary coil group 220 is grounded. The capacitor 10 and the resistor R are connected in parallel between the cathode terminal of the rectifier diode 12 and the other terminal 220b. In this way, only one terminal 220 a side of the secondary coil group 220 can be connected to the control circuit 3. Therefore, compared with the case where both terminals 220a and 220b of the secondary coil group 220 are connected to the control circuit 3, the number of wirings required for connection can be reduced, and the number of parts can be reduced. Thereby, the manufacturing cost of the electric power feeding control apparatus 1 can be reduced.

  As described above, according to the present invention, it is possible to provide a power supply control device that can stop power supply to an electrical device and is less likely to deteriorate over time when the electrical device is not connected to ground or is connected to a power supply with a wrong polarity. can do.

(Example 2)
In this example, as shown in FIG. 5, an electric device is connected to a single-phase three-wire AC power source 7. The AC power supply 7 of this example includes a cold terminal C that is grounded and two hot terminals H1 and H2. An AC current having an effective value of 100 V flows through the hot terminals H1 and H2 with the cold terminal C as a reference. The currents flowing through one hot terminal H1 and the other hot terminal H2 are 180 degrees out of phase with each other.

As in the first embodiment, a pair of power lines 40 and 41 are connected to the electric device 4. One power line 40 is connected to one hot terminal H1 of the AC power supply 7, and the other power line 41 is connected to the other hot terminal H2.
Similarly to the first embodiment, the electric device 4 includes a housing 400. A ground wire 42 is connected to the housing 400. By connecting the ground wire 42 to the ground 14, the electrical device 4 is grounded.

  The power supply control device 1 of this example stops power supply to the electric device 4 when the electric device 4 is not connected to the ground or when the power lines 40 and 41 are not connected to the hot terminals H1 and H2, respectively. It is configured to do.

As shown in FIG. 6, when the power lines 40 and 41 are connected to the hot terminals H1 and H2, respectively, and the ground wire 42 is connected to the ground 14 (normal use state), the primary current I1 from one hot terminal H1 is It flows to the ground 14 through the power line 40, the wiring 28, one primary coil 21 a, and the connection line 130. Further, the primary current I2 flows from the other hot line H2 to the ground 14 through the power line 41, the wiring 29, the other primary coil 21b, and the connection line 130. Since the intermediate point 13 is grounded, a voltage of 100 V is applied to each primary coil 21a, 21b.
Thus, in the normal use state, the primary current I flows through both the primary coils 21a and 21b. Along with this, an induced voltage is generated in the secondary coil group 220, and a DC voltage is applied to the connection part 30 of the control circuit 3.

Further, as shown in FIG. 7, the earth line 42 may be connected to the ground 14, the power line 40 may be connected to one hot terminal H <b> 1, and the power line 41 may be erroneously connected to the cold terminal C. In this case, the primary current I flows from one hot terminal H 1 to the ground 14 through the power line 40, the wiring 28, one primary coil 21 a, and the connection line 130. The primary current I does not flow through the other primary coil 21b.
Thus, since the primary current I flows through only one primary coil 21a, an induced voltage different from that in the normal use state (see FIG. 6) is generated in the secondary coil group 220. A voltage different from that in the normal use state is applied to the connection unit 30.

  Further, as shown in FIG. 8, the earth line 42 may be connected to the ground 14, the power line 41 may be connected to the other hot terminal H <b> 2, and the power line 40 may be erroneously connected to the cold terminal C. In this case, the primary current I flows from the other hot terminal H2 to the ground 14 through the power line 41, the wiring 29, the other primary coil 21b, and the connection line 130. The primary current I does not flow through the primary coil 21a. Along with this, an induced voltage is generated in the secondary coil group 220, and a DC voltage is applied to the connection part 30 of the control circuit 3. A voltage different from the normal use state (see FIG. 6) and the connection state shown in FIG.

  Further, as shown in FIG. 9, the power lines 40 and 41 may be connected to the hot terminals H1 and H2, respectively, and the earth wire 42 may not be connected to the ground 14. In this case, the primary current I flows through both primary coils 21a and 21b. Further, since the intermediate point 13 is not grounded, a voltage different from that in the normal use state (see FIG. 6) is applied to the primary coils 21a and 21b. Therefore, an induced voltage different from the normal use state is generated in the secondary coil group 220. As a result, a voltage different from the normal use state is applied to the connection part 30 of the control circuit 3.

  Further, as shown in FIG. 10, one power line 40 may be connected to the hot terminal H1, the other power line 41 may be connected to the cold terminal C, and the earth wire 42 may not be connected to the ground 14. In this case, the primary current I flows from the hot terminal H1 to the cold terminal C through the one power line 40, the wiring 28, the primary coils 21a and 21b, the wiring 29, and the other power line 41. In this case, since only a voltage of 100 V is applied between the terminals 210a and 210b of the primary coil group 210, an induced voltage different from that in the normal use state (see FIG. 6) is generated in the secondary coil group 220. As a result, a voltage different from the normal use state is applied to the connection part 30 of the control circuit 3.

  For example, as in the first embodiment, the turns ratio N1 / N2 = 34 of the number of turns N1 of the primary coil 21a and the number of turns N2 of the secondary coil 22a of one transformer 2a is set to 34, and the primary coil 21b of the other transformer 2b When the turn ratio N3 / N4 = 120 between the turn N3 and the turn N4 of the secondary coil 22b, the capacitance of the capacitor 10 is 10 μF, and the resistance R is 10 MΩ, the voltage applied to the connection portion 30 is in a normal use state (FIG. 6)), it becomes 19.8V. Moreover, in the use state of FIG. 7, it will be 12.8V, and in the use state of FIG. 8, it will be 6.5V. 9 is 16.1V in the usage state of FIG. 9, and 7.8V in the usage state of FIG.

Therefore, for example, if the relay 11 is connected only when the voltage applied to the connection unit 30 is 18 V or more, and the relay 11 is disconnected when the voltage is less than 18 V, the electric power can be supplied only in a normal use state. It is possible to supply power to the device 4.
In addition, the same configuration as that of the first embodiment is provided.

The effect of this example will be described. In this example, even when a single-phase three-wire AC power supply is used, the electrical device 4 is not connected to the ground (FIGS. 9 and 10), or is connected to the power supply with the wrong polarity (FIG. 7, 8 and 10), the power supply to the electric device 4 can be stopped.
In addition, the same functions and effects as those of the first embodiment are provided.

DESCRIPTION OF SYMBOLS 1 Power supply control apparatus 2 Transformer 21 Primary coil 210 Primary coil group 22 Secondary coil 220 Secondary coil group 3 Control circuit 4 Electric equipment 40 Power supply line (hot side)
41 Power line (cold side)
42 Ground wire 5 Outlet 6 Power plug

Claims (2)

A power supply control device for controlling power supply to an electrical device that requires ground connection,
A pair of transformers having different turns ratios of the primary coil and the secondary coil,
The primary coils of the pair of transformers are connected in series to form a primary coil group, and the secondary coils are connected in series to form a secondary coil group,
The primary coil group is connected in parallel with the electrical device to the power line of the electrical device,
Between the pair of primary coils is connected to the ground wire of the electrical equipment,
The secondary coil group is connected to a control circuit that controls power supply to the electrical equipment,
In accordance with the induced voltage generated in the secondary coil group, the control circuit determines whether or not the electric device is connected with an incorrect polarity to an AC power source having one terminal connected to the ground. It is detected whether or not the electric device is connected to the earth, and when the electric device is connected with the wrong polarity or when the electric device is not connected to the earth, the power supply to the electric device is stopped. A power supply control device characterized by being configured.   2. The power feeding control device according to claim 1, wherein one terminal of the secondary coil group is connected to an anode terminal of a rectifier diode, a cathode terminal of the rectifier diode is connected to the control circuit, and the secondary coil group is connected. The other terminal of the rectifier diode is grounded, and a capacitor and a resistor are connected in parallel between the cathode terminal of the rectifier diode and the other terminal, respectively.

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