JP6278815B2 - Terminal block and power equipment - Google Patents

Description

  The present invention relates to a terminal block and a power device.

  In a power converter (power device) such as a solar power generation facility, a terminal block formed by attaching a metal terminal fitting to a resin block is used to connect an external electric wire. In such a terminal block, an electric wire is connected to the conductive part of the terminal block by a terminal screw. If the current flows with the terminal screw loosened, the resistance between the electric wire and the terminal fitting will increase, and a spark will fly or heat will be generated. If such a heat generation state continues for a long time, the resin block may be deformed to cause ignition or smoke.

  In order to avoid such a situation, for example, Patent Document 1 discloses a configuration in which a thermal fuse that is blown when a set temperature is reached is embedded in a resin block. According to such a configuration, when the resistance between the electric wire and the terminal fitting increases and the resin block generates heat, the thermal fuse is blown to prevent energization and prevent the heat generation state from continuing. Yes.

JP 2002-343459 A

  However, according to the conventional terminal block, it is possible to prevent the heat generation state from continuing due to the melting of the thermal fuse, but the once fused thermal fuse cannot be reused. Therefore, in order to restore the operation of the solar power generation facility, there is a problem that repair by an engineer is necessary and it takes time to restore.

  Also, heat generated when the terminal screw is loose is likely to occur in a device in which a large current flows through the terminal block. Although the temperature inside the device rises due to the flow of a large current, this temperature rise is not an abnormality of the device. Therefore, it is necessary to use a temperature fuse with a set temperature that does not blow due to the temperature rise due to the flow of a large current. Therefore, there is a problem that it is difficult to select a set temperature of the thermal fuse. For example, if the set temperature of the thermal fuse is too high, the terminal block and wiring are likely to be damaged due to continued heat generation, and if the set temperature of the thermal fuse is too low, the temperature fuse may be blown out even though it is not a device malfunction. Operation is likely to occur.

  The present invention has been made in view of the above, and it is intended to obtain a terminal block capable of improving the detection accuracy of heat generation in a state where the terminal screw is loosened and facilitating the restoration work. Objective.

  The present invention has been made in view of the above, and when the terminal screw generates heat in a loose state, the power can be cut off to prevent the heat generation from continuing, and even if repair or the like is not performed. It aims at obtaining the terminal block of the power equipment which can be restored.

  In order to solve the above-described problems and achieve the object, the present invention provides a resin block, a conductive plate attached to the resin block, and one side and the other side of the conductive plate. A terminal screw for connecting the wiring, a first thermal element attached at a position away from the conductive plate installation area where the conductive plate is installed in plan view, and a conductive plate installation area where the conductive plate is installed in plan view And a second thermosensitive element attached to a position overlapping with the second thermosensitive element.

  According to the present invention, it is possible to improve the detection accuracy of heat generation in a state where the terminal screw is loosened, and to facilitate the restoration work.

FIG. 1 is a diagram illustrating a schematic configuration of a photovoltaic power generation system including a terminal block according to the first embodiment of the present invention. FIG. 2 is a perspective view showing the terminal block according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA shown in FIG. FIG. 4 is a wiring diagram inside the power converter and the substrate to which the thermistor is attached. FIG. 5 is a diagram showing the temperature of the thermistor when the terminal screw is not loose (normal). FIG. 6 is a diagram showing the temperature of the thermistor when heat generation due to loosening of the terminal screw occurs in the external wiring near the thermistor. FIG. 7 is a diagram illustrating the temperature of the thermistor when a failure occurs in the thermistor. FIG. 8 is a perspective view showing a terminal block according to the second embodiment of the present invention. 9 is a cross-sectional view taken along line BB shown in FIG.

  Hereinafter, a terminal block and a power device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a schematic configuration of a photovoltaic power generation system including a terminal block according to the first embodiment of the present invention. In the solar power generation system, DC power generated by the solar cell 1 is converted into AC power by a power converter (power device) 2 called a power conditioner. The AC power converted by the power converter 2 is supplied to the commercial power 4 through the distribution board 3 or supplied to the load 15 by a technique called grid connection. Here, when the generated power generated by the solar cell 1 is less than the power of the load 15, the insufficient power is supplied from the commercial power 4 to the load 15, and when the generated power is larger than the power of the load 15, The supplied power is supplied to commercial power 4. In addition, the capacity | capacitance of the power converter for homes currently marketed has many things of about 2kW-6kW.

  FIG. 2 is a perspective view showing the terminal block 30 according to the first exemplary embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA shown in FIG. The terminal block 30 is provided inside the power converter 2. The terminal block 30 is connected to the external wiring 5 of the DC input and AC output of the power converter 2. Similarly, the internal wiring 6 connected to the equipment in the power converter 2 is also connected to the terminal block 30.

  The terminal block 30 has the conductive plate 8 attached to the resin block 7 and electrically connects the external wiring 5 and the internal wiring 6. Terminal screws 9 are attached to the conductive plate 8 on one side and the other side, respectively. By fastening the terminal screw 9, the external wiring 5 and the internal wiring 6 are fixed to the conductive plate 8. As a result, the conductive plate 8 is electrically connected to the external wiring 5 and the internal wiring 6.

  A substrate 10 that is a printed wiring board is attached to the central portion of the resin block 7, and a plurality of thermistors 11 (11 a to 11 c) that are thermal elements are attached to the substrate. Among the plurality of thermistors 11, at least one thermistor (first thermal element) 11a is located at a position (outside of the terminal block 30) outside the conductive plate installation area C where the conductive plate 8 is installed in plan view. It is attached. The other thermistors (second heat sensitive elements) 11b and 11c are attached to positions (in the vicinity of the terminal screws 9) that overlap the conductive plate installation region C where the conductive plate 8 is installed in plan view.

  FIG. 4 is a wiring diagram inside the substrate 10 and the power converter 2 to which the thermistor 11 is attached. The plurality of thermistors 11 are connected to the connector 12 by outputting the common lines and the thermistors 11a to 11c independently so that the temperature of the thermistors 11 can be measured. The connector 12 is connected to a control circuit (control unit) 13 of the power converter 2.

  Next, the operation of the present invention will be described with reference to FIGS. FIG. 5 is a diagram showing the temperature of the thermistors 11a to 11c when the terminal screw 9 is not loose (normal). The horizontal axis indicates time, and the vertical axis indicates temperature. When the power converter 2 starts to operate at point A on the time axis, the thermistors 11 a to 11 c rise in temperature because the ambient temperature rises due to heat generated by the internal loss of the power converter 2. When the power converter 2 is stopped at the point A on the time axis, the thermistors 11a to 11c are lowered in temperature.

  The power converter 2 is designed so that the maximum temperature at this time is equal to or lower than the allowable temperature of the terminal block 30 (generally the upper limit temperature of the resin block 7). As described above, when the temperatures of the thermistors 11a to 11c (Ta, Tb, Tc) are all measured in the vicinity of the terminal block 30 in the normal state, a large difference does not appear. The thermistors 11b and 11c usually have a higher temperature than the thermistor 11a due to the contact resistance between the internal wiring 6, the conductive plate 8, and the terminal screw 9.

  FIG. 6 is a diagram showing the temperature of the thermistor 11 when heat generation due to loosening of the terminal screw 9 occurs in the external wiring 5 in the vicinity of the thermistor 11c. The looseness of the terminal screw 9 increases the contact resistance between the terminal screw 9, the external wiring 5, and the conductive plate 8, and heat is generated at the terminal screw 9 due to Joule heat generated by the current flowing therethrough. Due to this heat generation, the temperature Tc of the thermistor 11c suddenly rises as shown in FIG.

  The heat generation at this time is affected by the contact resistance described above, and the heat generation increases as the contact resistance increases. However, this contact resistance is not constant and changes depending on the degree of tightening of the terminal screw 9. Further, the temperature Tc of the thermistor 11c varies depending on the temperature transmission from the heat generating portion. For these reasons, when the temperature Tc of the thermistor 11c is monitored and the power converter 2 is stopped when it reaches a predetermined value, the operation is the same as when a conventional thermal fuse is used. It is difficult to prevent the terminal block 30 and the wirings 5 and 6 from being damaged.

  However, since the temperature Ta of the thermistor 11a is mounted so as to be located outside the terminal block 30, as shown in FIG. 6, heat generated by the loosening of the terminal screw 9 is generated in the external wiring 5 near the thermistor 11c. Even if it occurs, it will not rise significantly. Therefore, when the temperature difference Tc−Ta between the temperature Ta and the above-described Tc becomes larger than a predetermined value, the control circuit 13 cuts off the power supply from the power converter 2. Thereby, it is possible to prevent the current from flowing before the terminal block 30 and the wirings 5 and 6 are damaged, and to prevent the heat generation state from continuing. In this way, by monitoring the temperature difference Tc−Ta, it is possible to monitor the temperature rise caused by the looseness of the terminal screw 9 substantially. Therefore, it is possible to improve the accuracy of the determination to cut off the power supply.

  At this time, the control circuit 13 transmits an abnormal signal in order to quickly notify the user of the abnormality. Based on the reception of the abnormal signal, an alarm is issued by an LED (not shown), an alarm sound, or the like. The alarm device or LED that issues an alarm may be provided in a building in which the solar power generation system is installed or in the power converter 2 itself.

  Further, the control circuit 13 restores the supply of power when a reset operation is performed. The reset operation is, for example, a re-operation of a power switch (not shown) of the power converter 2. In this case, the power switch of the power converter 2 serves as a reset operation means for performing a reset operation. In addition, you may provide a reset operation means in the room | chamber interior of the building in which a solar power generation system is installed. Further, temperature difference information and the like for determining a temperature abnormality is stored in the storage unit 14 provided in the power converter 2. Further, the storage unit 14 and the control circuit 13 may be provided in the terminal block 30. Since the power supply can be restored only by a reset operation, troublesome work such as fuse replacement can be omitted, and the restoration work can be facilitated.

  The temperature difference Tc-Ta determined in advance for stopping the power converter 2 is affected by the actual structure of the terminal block 30, the mounting position of the thermistor 11, and the like. Therefore, it is determined by experiments or simulations that actually cause the terminal screws 9 to loosen. Further, the reference for stopping the power converter 2 can be a temperature difference in the vicinity of another terminal screw 9 as in the temperature difference Tc−Tb. However, when the other terminal screws 9 are also loose, the temperature rises in both thermistors 11b and 11c, so that the temperature difference Tc−Tb does not reach a predetermined value, and the power converter 2 is not stopped. In some cases, damage to the terminal block 30 and the wirings 5 and 6 cannot be prevented.

  Further, the temperature of the thermosensitive element such as the thermistor 11 may not be detected due to a failure or the like. In this case, usually, even if there is a temperature change, the resistance value or the like does not change, and in many cases always shows a constant temperature. FIG. 7 is a diagram showing the temperature of the thermistor 11 when such a failure occurs in the thermistor 11c.

  In FIG. 7, the thermistors 11a and 11b are the same as those in FIG. The thermistor 11c is out of order, and the temperature Tc caused thereby is always a constant value. As described above, the control circuit 13 transmits an abnormal signal even when a failure occurs such that the thermosensitive element such as the thermistor 11 has a constant temperature value. For example, when the temperature of the thermistor 11c does not change during a predetermined period or when the width of the temperature change is smaller than a predetermined value, the control circuit 13 determines that the temperature change of the thermistors 11a and 11b is in advance. When the value is larger than the predetermined value, it is determined that the thermistor 11c has failed, and an abnormal signal is transmitted. If it is determined that the thermistor has failed, an alarm different from the alarm at the time of temperature abnormality described above is issued. When the temperature of the thermosensitive element such as the thermistor 11 is a value that is not normal, for example, −30 degrees or less or 150 degrees or more, it is determined that the temperature is abnormal without comparing with other thermistors.

  Although the thermistor is shown as the thermosensitive element, other thermosensitive elements such as a thermocouple and a platinum thermometer can be applied in the same manner.

Embodiment 2. FIG.
FIG. 8 is a perspective view showing the terminal block 30 according to the second embodiment of the present invention. 9 is a cross-sectional view taken along line BB shown in FIG. In addition, about the structure similar to the said Embodiment 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. In the first embodiment, the case where the substrate 10 is installed in the central portion of the resin block 7 is shown. However, in the second embodiment, an example in which the substrate 10 is attached to the conductive plate 8 is shown.

  The conductive plate 8 is extended toward the internal wiring 6 than the example shown in the first embodiment (see also FIG. 2), and the substrate 10 is fixed to the extended conductive plate 8. Although the fixing position of the substrate 10 is different, at least one thermistor 11a among the plurality of thermistors 11 is located outside the conductive plate installation area C where the conductive plate 8 is installed in plan view (the outside of the terminal block 30). ). The other thermistors 11b and 11c are attached at positions (in the vicinity of the terminal screws 9) that overlap the conductive plate installation region C where the conductive plate 8 is installed in plan view. Since the other structure is the same as that of FIG. 2, description is abbreviate | omitted.

  By adopting such a structure, the thermistor 11 which is a thermosensitive element attached to the substrate 10 is in thermal contact with the conductive plate 8 having better thermal conductivity than the resin block 7, and the temperature of the conductive plate 8 is further increased. It can be measured accurately. That is, when heat is generated due to the looseness of the terminal screw 9, heat is transmitted to the conductive plate 8 having good heat conduction, so that more reliable operation can be expected as compared with the first embodiment.

  In addition, although this description demonstrated the power converter (electric power device) used for a solar power generation system, and the terminal block used for it, the temperature control apparatus which controls the inverter apparatus and heater which perform motor control etc., for example Needless to say, the present invention can be applied to a power device for controlling a relatively large power such as the above and a terminal block used for the power device.

  As described above, the terminal block according to the present invention is useful for a terminal block that easily rises in temperature when electric power is supplied.

  DESCRIPTION OF SYMBOLS 1 Solar cell, 2 Power converter (electric power device), 3 Distribution board, 4 Commercial power, 5 External wiring, 6 Internal wiring, 7 Resin block, 8 Conductive plate, 9 Terminal screw, 10 Board | substrate, 11 Thermistor, 11a Thermistor (first thermal element), 11b Thermistor (second thermal element), 11c Thermistor (second thermal element), 12 connector, 13 control circuit, 14 storage unit, 15 load, 30 terminal block, C conductive plate Installation area.

Claims (7)

A resin block;
A conductive plate attached to the resin block;
A terminal screw which is provided on one side and the other side of the conductive plate and connects a wiring to the conductive plate;
In a plan view, a first thermal element attached at a position deviating from a conductive plate installation area where the conductive plate is installed;
A second thermosensitive element attached to a position overlapping with a conductive plate installation region in which the conductive plate is installed in a plan view;
A board attached between the terminal screw provided on one side of the conductive plate and the terminal screw provided on the other side ;
It said first heat sensitive element and the second heat sensitive element, terminal blocks, characterized in Rukoto provided on the substrate. A resin block;
A conductive plate attached to the resin block;
A terminal screw which is provided on one side and the other side of the conductive plate and connects a wiring to the conductive plate;
In a plan view, a first thermal element attached at a position deviating from a conductive plate installation area where the conductive plate is installed;
A second thermosensitive element attached to a position overlapping with a conductive plate installation region in which the conductive plate is installed in a plan view;
The conductive plate is further extended to one side than the portion provided with the terminal screw on one side,
Further comprising a substrate attached to the stretched portion of the conductive plate;
It said first heat sensitive element and the second heat sensitive element, terminal block you and which are located on the substrate. A power device that supplies power input from a primary side to a secondary side,
The terminal block according to claim 1 or 2 ,
Control for judging that the temperature is abnormal and cutting off the supply of power when the difference between the temperature detected by the first thermal element and the temperature detected by the second thermal element is larger than a predetermined value. A power device comprising: a circuit; The power device according to claim 3 , wherein the control circuit transmits an abnormality signal when determining that the temperature is abnormal. 5. The power device according to claim 3 , wherein the control circuit restores the power supply when a reset operation is performed after determining that the temperature is abnormal and shutting off the power supply. 6. In the case where there is no temperature change of one of the first and second heat sensitive elements in a predetermined period, or the width of the temperature change is smaller than a predetermined value. there, when the temperature changes in the other heat sensitive element is greater than a predetermined value, said determining that one thermal element is abnormal, claim 3, characterized in that to transmit the abnormality signal 5 The power device according to any one of the above. 7. The power device according to claim 3, wherein DC power input from the primary side is converted to AC power and supplied to the secondary side. 8.

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