Switch device and load control system

Abstract

To provide a switch device and the like, capable of inhibiting excessive stopping of the operation of a load.SOLUTION: A switch device 1 comprises: a first terminal T1 and a second terminal T2 that are provided on a power supply path SL connecting an AC power supply AC and a load L; a first semiconductor switch 10 provided between the first terminal T1 and the second terminal T2; an electromagnetic relay 40 connected in series to the first semiconductor switch 10; a second semiconductor switch 20 connected in parallel to the first semiconductor switch 10 and the electromagnetic relay 40; and a control unit 50 that controls the first semiconductor switch 10, the second semiconductor switch 20, and the electromagnetic relay 40. The control unit 50 outputs an ON command to the second semiconductor switch 20 when a voltage equal to or higher than a first threshold v1 is applied to the first semiconductor switch 10, and controls opening and closing of a contact of the electromagnetic relay 40 depending on whether or not the number of times the voltage equal to or higher than the first threshold v1 has been applied exceeds a predetermined number of times c1 during a prescribed period ta.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a switch device for controlling a load, and a load control system including the switch device. [Background technology]

[0002] Conventionally, devices for controlling a load have been known. As an example of this type of device, Patent Document 1 discloses a device including a semiconductor switch provided in a power supply path connecting a power source and a load, and an electromagnetic relay provided between the semiconductor switch and the load in the power supply path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-77447 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in a switch device, the voltage applied to a semiconductor switch is detected, and if a high voltage is detected, an electromagnetic relay is turned off to protect the semiconductor switch, etc. However, if the electromagnetic relay is turned off every time a high voltage is detected, the number of times the load is stopped increases, which is inconvenient for the user who uses the load.

[0005] The present invention provides a switch device and the like that can prevent the operation of a load from being stopped more than necessary. [Means for solving the problem]

[0006] One aspect of a switch device of the present invention includes a first terminal and a second terminal provided in a power supply path connecting an AC power source and a load, a first semiconductor switch provided in the power supply path between the first terminal and the second terminal, an electromagnetic relay provided in the power supply path between the first terminal and the second terminal and connected in series to the first semiconductor switch, a second semiconductor switch connected in parallel to the first semiconductor switch and the electromagnetic relay, and a control unit that switches between conductive and non-conductive states of the first semiconductor switch, switches between outputting an on command and releasing an on command to the second semiconductor switch, and switches between opening and closing of a contact of the electromagnetic relay, wherein the control unit outputs the on command to the second semiconductor switch when a voltage equal to or greater than a first threshold is applied to the first semiconductor switch, and controls the opening and closing of the contact of the electromagnetic relay depending on whether the number of times a voltage equal to or greater than the first threshold is applied in a specified period exceeds a predetermined number of times. Effect of the Invention

[0007] The switch device etc. of the present invention can prevent the operation of the load from being stopped more than necessary. [Brief description of the drawings]

[0008] [Figure 1] 1 is a circuit diagram of a switch device and a load control system according to an embodiment. [Diagram 2] 4 is a timing chart showing an operation during normal operation of the switch device according to the embodiment. [Diagram 3] 11 is a diagram showing an example of a first threshold, a specified period, and a predetermined number of times. FIG. [Figure 4] 6 is a timing chart showing an example of an operation when a voltage equal to or greater than a first threshold is detected in the switch device according to the embodiment. [Diagram 5] 10 is a timing chart showing another example of the operation when a voltage equal to or greater than the first threshold is detected in the switch device according to the embodiment. [Figure 6]4 is a flowchart showing the operation of the switch device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims showing the highest concept of the present invention will be described as optional components.

[0010] In addition, each drawing is a schematic diagram and is not necessarily a precise illustration. In each drawing, the same reference numerals are used for substantially the same configurations, and duplicated explanations are omitted or simplified.

[0011] (Embodiment) A switch device according to an embodiment will be described with reference to FIG.

[0012] FIG. 1 is a circuit diagram of a switch device 1 and a load control system 2 according to an embodiment.

[0013] As shown in FIG. 1, the load control system 2 includes an AC power source AC, a load L, and a switch device 1.

[0014] The AC power source AC is, for example, a commercial power source of 100V AC or 200V AC. The AC power source AC outputs a sinusoidal AC current (or AC voltage) having a constant period. Figure 1 shows a single-phase two-wire power supply path SL that connects the AC power source AC and a load L.

[0015] The load L is, for example, a lighting device or an air conditioning device. The load L is installed, for example, on a ceiling, which is an example of a building construction material. Although one load L is shown in the figure, the present invention is not limited to this, and the load L may be composed of a plurality of devices connected in parallel to each other. The operation of the load L is controlled by the AC waveform of the AC power source AC and the switch device 1.

[0016] The switch device 1 switches between supplying and not supplying power output from an AC power source AC, thereby controlling the operation of a load L. The switch device 1 is installed, for example, on a wall, which is an example of a construction material of a building.

[0017] As shown in FIG. 1, the switch device 1 includes a first terminal T1, a second terminal T2, a first semiconductor switch 10, a second semiconductor switch 20, an electromagnetic relay 40, a power supply circuit section 30, and a control section 50.

[0018] The first terminal T1 and the second terminal T2 are provided on a power supply path SL that connects an AC power source AC and a load L. In this example, the first terminal T1 is located closer to the AC power source AC than the second terminal T2, and the second terminal T2 is located closer to the load L than the first terminal T1. In other words, the first terminal T1 is located closer to the AC power source AC than the first semiconductor switch 10, and the second terminal T2 is located closer to the load L than the first semiconductor switch 10.

[0019] The first semiconductor switch 10 is provided between a first terminal T1 and a second terminal T2 in a power supply path SL. The first semiconductor switch 10 is composed of two field effect transistors 11 and 12 connected in series to each other. The field effect transistors are, for example, N-type MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0020] Of the two field effect transistors, one field effect transistor 11 has a gate connected to the control unit 50, a drain connected to the first terminal T1, and a source connected to the source of the other field effect transistor 12. The other field effect transistor 12 has a gate connected to the control unit 50, a drain connected to the electromagnetic relay 40, and a source connected to the source of the one field effect transistor 11.

[0021] The first semiconductor switch 10 switches between a conductive state and a non-conductive state in response to a first gate signal s1 output from the control unit 50. For example, the field effect transistors 11 and 12 of the first semiconductor switch 10 are instantly turned on by an ON command of the first gate signal s1, and are instantly turned off by an OFF command of the first gate signal s1. After being turned off, the first semiconductor switch 10 maintains the non-conductive state until the next ON command is received.

[0022] The electromagnetic relay 40 is provided between the first semiconductor switch 10 and the second terminal T2 in the power supply path SL, and is connected in series to the first semiconductor switch 10. The electromagnetic relay 40 is, for example, a contact relay that switches between open and closed contacts by a pulse signal output from the control unit 50. The electromagnetic relay 40 is, for example, a self-holding latching relay that can maintain a closed or open state after switching. By using a latching relay as the electromagnetic relay 40, it is possible to reduce power consumption compared to using a self-resetting relay. In addition, in this switch device 1, since the electromagnetic relay 40 is connected in series to the first semiconductor switch 10, it is possible to lower the voltage applied to the first semiconductor switch 10 and to employ low-voltage field effect transistors 11 and 12 as the first semiconductor switch 10.

[0023] The contacts of the electromagnetic relay 40 are closed during normal operation. Normal operation refers to a time when the first semiconductor switch 10 and the like are operating periodically based on the alternating current power source AC (see FIG. 2). The opening and closing operation of the contacts of the electromagnetic relay 40 will be described later.

[0024] The second semiconductor switch 20 is a semiconductor element that has a higher withstand voltage and is capable of passing a large current than the first semiconductor switch 10. The second semiconductor switch 20 is connected in parallel to the first semiconductor switch 10 and the electromagnetic relay 40. Specifically, one end of the second semiconductor switch 20 is connected to a node n1 between the first terminal T1 and the first semiconductor switch 10, and the other end of the second semiconductor switch 20 is connected to a node n2 between the electromagnetic relay 40 and the second terminal T2. In this example, the first terminal T1 and the node n1 are at the same potential, and the second terminal T2 and the node n2 are at the same potential.

[0025] The second semiconductor switch 20 is a silicon controlled rectifier (SCR) such as a thyristor or a bidirectional thyristor (e.g., a triac). The second semiconductor switch 20 switches between a conductive state and a non-conductive state based on the second gate signal s2 output from the control unit 50 and the current flowing through the second semiconductor switch 20 itself. For example, the second semiconductor switch 20 becomes conductive by receiving an ON command of the second gate signal s2. On the other hand, when the second semiconductor switch 20 receives the release of the ON command of the second gate signal s2, the second semiconductor switch 20 does not immediately become non-conductive but maintains the conductive state while a current flows through it, and becomes non-conductive when the current flowing through it becomes equal to or less than a certain value (e.g., zero). After becoming non-conductive, the second semiconductor switch 20 maintains the non-conductive state until the next ON command is received.

[0026] The power supply circuit unit 30 is a circuit that generates a drive voltage (control voltage) for driving the control unit 50. The power supply circuit unit 30 is electrically connected to a first terminal T1 (or node n1) via a first rectifier element 31, and is electrically connected to a node n1a via a second rectifier element 32. Specifically, the anode of the first rectifier element 31 is connected to the first terminal T1 (or node n1), and the cathode is connected to the power supply circuit unit 30 via a node n3 located between the first rectifier element 31 and the power supply circuit unit 30. The anode of the second rectifier element 32 is connected to the node n1a, and the cathode is connected to the power supply circuit unit 30 via the node n3.

[0027] The power supply circuit unit 30 is electrically connected to the second terminal T2 (or node n2) in addition to the node n1a. That is, the power supply circuit unit 30 is connected to the first terminal T1 via a first rectifier element 31, and to the node n1a via a second rectifier element 32, and is further electrically connected to the second terminal T2 (or node n2) via a third rectifier element 33 different from the second rectifier element 32.

[0028] The power supply circuit unit 30 obtains power from the first terminal T1 and the second terminal T2 using an AC power supply AC as a power source. The power supply circuit unit 30 converts the obtained power into a predetermined DC voltage and outputs it to the control unit 50 as a drive voltage.

[0029] The control unit 50 includes a voltage detection unit 58, a first gate circuit 51, a second gate circuit 52, and an MCU (Micro Controller Unit) 55.

[0030] The voltage detection unit 58 is a circuit that detects the voltage applied to the first semiconductor switch 10.

[0031] One end of the voltage detection unit 58 is connected to the node n1, and the other end is connected to a node n1a between the first semiconductor switch 10 and the electromagnetic relay 40. The voltage detection unit 58 is configured to detect the potential of either end of the first semiconductor switch 10 (node ​​n1 or n1a). Specifically, the voltage detection unit 58 is connected to the first terminal T1 (or node n1) via the first rectifier element 31, and detects the potential at the first terminal T1. The voltage detection unit 58 is also connected to the node n1a via the second rectifier element 32, and detects the potential at the node n1a.

[0032] The voltage detection unit 58 is connected to the second gate circuit 52 and controls the operation of the second gate circuit 52. When the voltage applied to the first semiconductor switch 10 is equal to or greater than the first threshold voltage v1, the voltage detection unit 58 activates the second gate circuit 52 to output an ON command to the second semiconductor switch 20.

[0033] Each of the first gate circuit 51 and the second gate circuit 52 is configured by a logic circuit.

[0034] The first gate circuit 51 is connected to the gate of the first semiconductor switch 10. Specifically, the first gate circuit 51 is connected to the gate of one field effect transistor 11 and the gate of the other field effect transistor 12. The first gate circuit 51 outputs a first gate signal s1 to the gates of the two field effect transistors 11 and 12, thereby switching the first semiconductor switch 10 between conductive and non-conductive states.

[0035] The second gate circuit 52 is connected to the gate of the second semiconductor switch 20. The second gate circuit 52 outputs a second gate signal s2 to the gate of the second semiconductor switch 20, thereby providing an on command and a release of the on command to the second semiconductor switch 20.

[0036] The MCU 55 is connected to the first gate circuit 51 and the second gate circuit 52. Using the first gate circuit 51 and the second gate circuit 52, the MCU 55 controls switching of the first semiconductor switch 10 between conductive and non-conductive states and switching of the output of an ON command and a release of the ON command for the second semiconductor switch 20 at every predetermined period. The predetermined period is, for example, half the period appearing in the AC waveform of the AC power source AC. Note that the predetermined period may be the same as the period appearing in the AC waveform of the AC power source AC, or may be a multiple of the half period appearing in the AC waveform.

[0037] FIG. 2 is a timing chart showing the operation of the switch device 1 during normal operation.

[0038] 2 shows the voltage detected by the voltage detector 58, the second gate signal s2 input to the second semiconductor switch 20, the first gate signal s1 input to the first semiconductor switch 10, and a contact open signal for opening the contact of the electromagnetic relay 40. Note that these detected voltages and signals are the same in the following Figures 4 and 5.

[0039] For example, the control unit 50 outputs an ON command and a release of the ON command to the second semiconductor switch 20 so as to straddle the falling edge (t=t2) from conduction to non-conduction after making the first semiconductor switch 10 conductive (t=t1). Specifically, the control unit 50 outputs an ON command to the second semiconductor switch 20 before switching the first semiconductor switch 10 from conduction to non-conduction, thereby putting the second semiconductor switch 20 into a conductive state. In addition, the control unit 50 outputs a release of the ON command to the second semiconductor switch 20 before the current of the AC power source AC becomes zero after switching the first semiconductor switch 10 into non-conduction.

[0040] The switch device 1 of the present embodiment has the following configuration in order to protect the first semiconductor switch 10 and to prevent the operation of the load L from being stopped more than necessary.

[0041] When a voltage equal to or greater than the first threshold v1 is applied to the first semiconductor switch 10, the control unit 50 outputs an ON command to the second semiconductor switch 20. Specifically, when the voltage detection unit 58 of the control unit 50 detects that the voltage applied to the first semiconductor switch 10 is equal to or greater than the first threshold v1, the control unit 50 operates the second gate circuit 52 to output an ON command to the second semiconductor switch 20. This ON command places the second semiconductor switch 20 in a conductive state, thereby preventing a large voltage from being applied to the first semiconductor switch 10.

[0042] In addition, when a voltage equal to or greater than the first threshold value v1 is applied to the first semiconductor switch 10, the control unit 50 controls the opening and closing of the contacts of the electromagnetic relay 40 depending on whether or not the number of times that a voltage equal to or greater than the first threshold value v1 is applied within a specified period ta exceeds a predetermined number of times c1.

[0043] The control unit 50 has a counter that counts the number of times a voltage equal to or greater than the first threshold value v1 is applied. The control unit 50 also has a storage unit that stores the first threshold value v1, the specified period ta, and a predetermined number of times c1.

[0044] 3 is a diagram showing an example of the first threshold v1, the specified period ta, and the predetermined number of times c1, along with selection ranges for setting the first threshold v1, the specified period ta, and the predetermined number of times c1.

[0045] The first threshold v1 is a voltage lower than the withstand voltage of the first semiconductor switch 10, and is a voltage between 0.4 and 0.8 times the withstand voltage (or allowable voltage) of the first semiconductor switch 10. For example, when the withstand voltage of the first semiconductor switch 10 is 60V, the first threshold v1 is set to 25V. The specified period ta is a period selected from a range of 30 to 90 seconds. The specified period ta is set to, for example, 50 seconds. The specified period ta may be determined according to the General Rules for Test Methods of Grid-Interconnection Protection Devices and the like (JETGR0002-1-2.0(2011)). The predetermined number of times c1 is a detection number used as a reference for determining whether or not the load L needs to be stopped, and is the number of detections of a voltage equal to or higher than the first threshold v1. The predetermined number of times c1 is set to, for example, once or twice.

[0046] 4 is a timing chart showing an example of the operation of the switch device 1 when a voltage equal to or greater than the first threshold value v1 is detected. The figure shows the operation of the switch device 1 when the number of times a voltage equal to or greater than the first threshold value v1 is detected does not exceed a predetermined number of times c1. Here, an example is shown in which the number of detections is the first and the predetermined number of times c1 is 1, that is, an example in which "the number of detections is first time≦the predetermined number of times c1".

[0047] The control unit 50 judges whether or not a voltage equal to or greater than the first threshold value v1 is applied to the first semiconductor switch 10 based on the detected voltage detected by the voltage detection unit 58. When the control unit 50 judges that a voltage equal to or greater than the first threshold value v1 is applied to the first semiconductor switch 10, it outputs an ON command to the second semiconductor switch 20 to make the second semiconductor switch 20 conductive. The time from when the ON command is output to the second semiconductor switch 20 until the ON command is released is, for example, 100 ms. The second semiconductor switch 20 maintains the conductive state even after receiving the output of the ON command release from the control unit 50, and changes the conductive state to a non-conductive state when the current of the AC power source AC becomes equal to or less than a predetermined current value.

[0048] As shown in FIG. 4, the control unit 50 does not output a contact open signal to open the contact of the electromagnetic relay 40 if the number of times that a voltage equal to or greater than the first threshold v1 is applied during the specified period ta does not exceed a predetermined number c1. Therefore, the contact of the electromagnetic relay 40 remains closed. In the load control system 2, while the second semiconductor switch 20 is in a conductive state, the control of the load L by the first semiconductor switch 10 is not performed, but when the second semiconductor switch 20 returns to a non-conductive state, the control of the load L is performed as in normal operation. In this way, by controlling the opening and closing of the contact of the electromagnetic relay 40 depending on the number of times that a voltage equal to or greater than the first threshold v1 is applied, it is possible to prevent the operation of the load L from being stopped more than necessary.

[0049] If the number of times that a voltage equal to or greater than the first threshold v1 has been applied during the specified period ta does not exceed a predetermined number c1, the control unit 50 resets the count of the number of times that a voltage equal to or greater than the first threshold v1 has been applied.

[0050] FIG. 5 is a timing chart showing another example of the operation when a voltage equal to or greater than the first threshold value v1 is detected in the switch device 1. In FIG.

[0051] The figure shows the operation of the switch device 1 when the number of detections of a voltage equal to or greater than the first threshold v1 exceeds a predetermined number c1. Here, an example is shown in which the number of detections is n (e.g., n=2) and the predetermined number c1 is 1, that is, "nth detection number>predetermined number c1."

[0052] For example, in the switch device 1, if there is a problem with the on operation of the second semiconductor switch 20, the off operation of the electromagnetic relay 40, or the on operation of the first semiconductor switch 10, the voltage detection unit 58 frequently detects a voltage equal to or greater than the first threshold value v1.

[0053] When the number of times that a voltage equal to or greater than the first threshold value v1 is applied during a specified period ta exceeds a predetermined number c1, the control unit 50 outputs a contact open signal to open the contact of the electromagnetic relay 40. The contact open signal is a one-pulse signal, and the pulse width of the contact open signal is, for example, 10 ms. This contact open signal causes the contact of the electromagnetic relay 40 to be in an open state.

[0054] After a predetermined time has elapsed since the one-pulse contact open signal falls, the control unit 50 outputs a release of the ON command for the second semiconductor switch 20. The predetermined time from the fall of the contact open signal to the output of the release of the ON command for the second semiconductor switch 20 is, for example, 60 ms.

[0055] By such operation control of the control unit 50, the control of the load L by the switch device 1 is stopped.

[0056] The control unit 50 outputs a signal notifying that an abnormality has occurred in the switch device 1 when the number of times that a voltage equal to or greater than the first threshold value v1 has been applied to the first semiconductor switch 10 during a specified period ta exceeds a predetermined number c1. For example, the control unit 50 may notify the outside of the information indicating the occurrence of the abnormality using an LED lamp, or may notify a communication terminal such as a smartphone via a wireless communication module. This makes it possible to notify information regarding the occurrence of an abnormality in the switch device 1 and to manage the occurrence state of the abnormality.

[0057] [Switch device operation] The operation of the switch device 1 will be described with reference to FIG.

[0058] FIG. 6 is a flowchart showing the operation of the switch device 1.

[0059] The switch device 1 detects the voltage applied to the first semiconductor switch 10 using the voltage detection unit 58 (step S10). The sampling period for voltage detection by the voltage detection unit 58 is, for example, 10 ms.

[0060] The switch device 1 determines whether or not a voltage equal to or greater than the first threshold value v1 is applied to the first semiconductor switch 10 (step S20).

[0061] If a voltage equal to or greater than the first threshold v1 is not applied (No in S20), it is determined whether or not the total time of sampling of voltage detection by the voltage detection unit 58 has passed the specified period ta (step S30). If the specified period ta has not passed (No in S30), the process returns to step S10 and voltage detection continues. If the specified period ta has passed (Yes in S30), the number of times that a voltage equal to or greater than the first threshold v1 was applied during the specified period ta was small. In this case, the switch device 1 resets the count of the number of times that a voltage equal to or greater than the first threshold v1 was applied to 0, and sets the total time of sampling of voltage detection to 0 seconds (step S40), and returns to step S10.

[0062] In step S20, when a voltage equal to or greater than the first threshold v1 is detected (Yes in S20), the switch device 1 outputs an ON command to the second semiconductor switch 20 (step S50). This causes the second semiconductor switch 20 to become conductive, thereby preventing a higher voltage from being applied to the first semiconductor switch 10.

[0063] Furthermore, when a voltage equal to or greater than the first threshold value v1 is detected, the switch device 1 increments the counter of the control unit 50 (step S60).

[0064] Next, the switch device 1 determines whether or not the count number of the counter has exceeded a predetermined number c1 (step S70). If the count number has not exceeded the predetermined number c1 (No in S70), the process returns to step S10 and continues detecting the voltage.

[0065] On the other hand, if the number of times exceeds the predetermined number c1 (Yes in S70), the switch device 1 outputs a contact open signal to the electromagnetic relay 40 (step S80). When the contact of the electromagnetic relay 40 opens due to the contact open signal, control of the load L by the switch device 1 is stopped. By executing these steps S10 to S80, it is possible to prevent the operation of the load L from being stopped more than necessary, and to stop the operation of the switch device 1 when it is really necessary to stop the switch device 1.

[0066] (summary) The switch device of the present disclosure will be exemplified below.

[0067] The switch device 1 of Example 1 includes a first terminal T1 and a second terminal T2 provided in a power supply path SL connecting an alternating current power source AC and a load L, a first semiconductor switch 10 provided between the first terminal T1 and the second terminal T2 in the power supply path SL, an electromagnetic relay 40 provided between the first terminal T1 and the second terminal T2 in the power supply path SL and connected in series to the first semiconductor switch 10, a second semiconductor switch 20 connected in parallel to the first semiconductor switch 10 and the electromagnetic relay 40, and a control unit 50 that switches between conductive and non-conductive states of the first semiconductor switch 10, switches the output of an on command and release of an on command for the second semiconductor switch 20, and switches between opening and closing the contacts of the electromagnetic relay 40. When a voltage equal to or greater than a first threshold value v1 is applied to the first semiconductor switch 10, the control unit 50 outputs an ON command to the second semiconductor switch 20, and controls the opening and closing of the contacts of the electromagnetic relay 40 depending on whether the number of times a voltage equal to or greater than the first threshold value v1 is applied within a specified period ta exceeds a predetermined number of times c1.

[0068] In this way, when a voltage equal to or greater than the first threshold v1 is applied to the first semiconductor switch 10, an ON command is output to the second semiconductor switch 20, thereby preventing a higher voltage from being applied to the first semiconductor switch 10. Furthermore, by controlling the opening and closing of the contacts of the electromagnetic relay 40 depending on whether the number of times a voltage equal to or greater than the first threshold v1 is applied in the specified period ta exceeds a predetermined number c1, it is possible to reduce, for example, the number of times the contacts of the electromagnetic relay 40 are opened more than necessary. This makes it possible to prevent the operation of the load L from being stopped more than necessary.

[0069] The switch device 1 described in Example 2 is the switch device described in Example 1, and the control unit 50 may output a contact open signal to open the contacts of the electromagnetic relay 40 when the number of times a voltage equal to or greater than the first threshold value v1 is applied within a specified period ta exceeds a predetermined number of times c1.

[0070] In this way, when the number of times a voltage equal to or greater than the first threshold value v1 is applied exceeds a predetermined number c1, the contacts of the electromagnetic relay 40 are opened, so that the control of the load L can be stopped when it is truly necessary to stop the control of the load L.

[0071] The switch device 1 described in Example 3 is the switch device described in Example 2, in which the contact open signal is a pulse signal, and the control unit 50 may output a cancellation of the on command for the second semiconductor switch 20 after a predetermined time has elapsed since the contact open signal falls.

[0072] According to this, the second semiconductor switch 20 can be kept in a conductive state until the contact of the electromagnetic relay 40 that has received the contact open signal changes to an open state. This makes it possible to prevent an overvoltage from being applied to the first semiconductor switch 10.

[0073] The switch device 1 described in Example 4 is the switch device described in Example 3, and the second semiconductor switch 20 may maintain the conductive state even after receiving an output from the control unit 50 to cancel the on command, and may change the conductive state to a non-conductive state when the current of the alternating current power source AC becomes equal to or lower than a predetermined current value.

[0074] According to this, the second semiconductor switch 20 can be kept in a conductive state until the current flowing through the second semiconductor switch 20 becomes equal to or lower than a predetermined current value, thereby making it possible to prevent an overvoltage from being applied to the first semiconductor switch 10.

[0075] The switch device 1 described in Example 5 is the switch device 1 described in any of Examples 1 to 4, and the control unit 50 may reset the count of the number of times a voltage equal to or greater than the first threshold v1 has been applied if the number of times a voltage equal to or greater than the first threshold v1 has been applied within a specified period ta does not exceed a predetermined number c1.

[0076] In this way, by resetting the count when the number of times a voltage equal to or greater than the first threshold value v1 is applied within the specified period ta is small, it is possible to prevent the operation of the load L from being stopped more than necessary.

[0077] The switch device 1 according to a sixth embodiment is the switch device according to any one of the first to fifth embodiments, and the first threshold value v1 may be a voltage lower than the withstand voltage of the first semiconductor switch .

[0078] In this manner, by setting the first threshold v1 to a voltage lower than the withstand voltage of the first semiconductor switch 10, application of an overvoltage to the first semiconductor switch 10 can be suppressed.

[0079] The switch device 1 according to Example 7 is the switch device according to any one of Examples 1 to 6, and the specified period ta may be a period selected from the range of 30 seconds to 90 seconds.

[0080] This makes it possible to control the opening and closing of the contacts of the electromagnetic relay 40 depending on whether the number of times a voltage equal to or greater than the first threshold value v1 is applied exceeds a predetermined number c1 during a period selected from the above range. Therefore, for example, it is possible to reduce the number of times the contacts of the electromagnetic relay 40 are opened more than necessary. This makes it possible to prevent the operation of the load L from being stopped more than necessary.

[0081] The switch device 1 according to an eighth embodiment is the switch device according to any one of the first to seventh embodiments, and the predetermined number of times c1 may be one or two.

[0082] According to this, the opening and closing of the contacts of the electromagnetic relay 40 can be controlled depending on whether the number of times that a voltage equal to or greater than the first threshold value v1 is applied during the specified period ta exceeds one or two times. Therefore, for example, the number of times that the contacts of the electromagnetic relay 40 are opened more than necessary can be reduced. This makes it possible to prevent the operation of the load L from being stopped more than necessary.

[0083] The switch device 1 described in Example 9 is the switch device described in any of Examples 1 to 8, and the control unit 50 may output a signal notifying that an abnormality has occurred in the switch device 1 when the number of times a voltage equal to or greater than the first threshold value v1 is applied within a specified period ta exceeds a predetermined number c1.

[0084] This makes it possible to notify information regarding the occurrence of an abnormality in the switch device 1 and to manage the occurrence state of the abnormality.

[0085] The switch device 1 described in Example 10 is the switch device described in any of Examples 1 to 9, and the control unit 50 may have a voltage detection unit 58 that detects a voltage applied to the first semiconductor switch 10, and may determine whether a voltage equal to or greater than a first threshold value v1 has been applied to the first semiconductor switch 10 based on the detection voltage detected by the voltage detection unit 58.

[0086] In this manner, by detecting the voltage applied to the first semiconductor switch 10 using the voltage detection unit 58, application of an overvoltage to the first semiconductor switch 10 can be prevented.

[0087] The switch device 1 described in Example 11 may be the switch device described in Example 10, in which the voltage detection unit 58 is connected to one end of the first semiconductor switch 10 via the first rectifying element 31 and to the other end of the first semiconductor switch 10 via the second rectifying element 32.

[0088] This configuration makes it possible to reliably detect the voltage applied across the first semiconductor switch 10. This makes it possible to prevent an overvoltage from being applied to the first semiconductor switch 10.

[0089] A load control system 2 according to Example 12 includes the above-mentioned switch device 1 and a load L connected to the switch device 1.

[0090] This makes it possible to provide the load control system 2 that can prevent the operation of the load L from being stopped more than necessary.

[0091] (Other forms) Although the switch device has been described above based on the embodiment, the present invention is not limited to the above embodiment. For example, the present invention also includes forms obtained by applying various modifications to the above embodiment that a person skilled in the art can conceive, and forms realized by arbitrarily combining the components and functions of the embodiment within the scope of the gist of the present invention.

[0092] In the above, the electromagnetic relay 40 is disposed on the load L side as viewed from the first semiconductor switch 10, but this is not limiting. For example, the electromagnetic relay 40 may be disposed on the AC power source AC side as viewed from the first semiconductor switch 10. In other words, the electromagnetic relay 40 may be provided between the first semiconductor switch 10 and the first terminal T1 in the power supply path SL.

[0093] In the above, an example has been described in which the voltage detection unit 58 is included in the control unit 50, but this is not limiting. The voltage detection unit 58 may be provided outside the control unit 50 as a separate component different from the control unit 50. In this case, the drive voltage of the voltage detection unit 58 may be supplied from the power supply circuit unit 30. Furthermore, the voltage detection unit 58 may be provided outside the MCU 55 as a separate component different from the MCU 55, or the voltage detection unit 58 may be provided inside the MCU 55. In other words, the MCU 55 may have the function of the voltage detection unit 58.

[0094] In the above, an example has been shown in which the opening and closing of the contacts of the electromagnetic relay 40 is controlled depending on whether the number of times a voltage equal to or greater than the first threshold v1 has been applied in the specified period ta exceeds a predetermined number of times c1, but the present invention is not limited to this. For example, the control unit 50 may have a second threshold different from the first threshold v1, and when the voltage applied to the first semiconductor switch 10 becomes equal to or greater than the second threshold, the control unit 50 may immediately open the contacts of the electromagnetic relay 40 and stop the operation of the switch device 1. The second threshold is a voltage that is greater than the first threshold v1 and smaller than the withstand voltage of the first semiconductor switch 10. [Explanation of symbols]

[0095] 1 Switching device 2. Load Control System 10 First semiconductor switch 11, 12 Field effect transistor 20 Second semiconductor switch 30 Power supply circuit section 31 First rectifier element 32 Second rectifier element 40 Electromagnetic Relay 50 Control section 51 First gate circuit 52 Second gate circuit 58 Voltage detection section AC alternating current power supply c1 A predetermined number of times L load SL Power supply route T1 Terminal 1 T2 Second terminal ta Specified period v1 First Threshold

Claims

1. a first terminal and a second terminal provided on a power supply path connecting an AC power source and a load; a first semiconductor switch provided in the power supply path between the first terminal and the second terminal; an electromagnetic relay provided in the power supply path between the first terminal and the second terminal and connected in series to the first semiconductor switch; a second semiconductor switch connected in parallel to the first semiconductor switch and the electromagnetic relay; a control unit that switches the first semiconductor switch between conductive and non-conductive states, switches the output of an ON command and a release of the ON command for the second semiconductor switch, and switches the open / closed contacts of the electromagnetic relay; Equipped with The control unit outputs the ON command to the second semiconductor switch when a voltage equal to or greater than a first threshold is applied to the first semiconductor switch, and controls opening and closing of a contact of the electromagnetic relay depending on whether or not the number of times that the voltage equal to or greater than the first threshold is applied within a specified period exceeds a predetermined number of times. Switch device.

2. The control unit outputs a contact open signal to open a contact of the electromagnetic relay when the number of times that the voltage equal to or greater than the first threshold value is applied during the specified period exceeds a predetermined number of times. The switch device according to claim 1 .

3. the contact opening signal is a pulse signal, The control unit outputs a release of the ON command for the second semiconductor switch after a predetermined time has elapsed since the contact open signal falls. The switch device according to claim 2 .

4. The second semiconductor switch maintains the conductive state even after receiving a release output of the ON command from the control unit, and changes the conductive state to a non-conductive state when the current of the AC power supply becomes equal to or lower than a predetermined current value. The switch device according to claim 3.

5. The control unit resets a count of the number of times a voltage equal to or greater than the first threshold is applied when the number of times a voltage equal to or greater than the first threshold is applied during the specified period does not exceed a predetermined number of times. The switch device according to claim 1 .

6. The first threshold is a voltage lower than a withstand voltage of the first semiconductor switch. The switch device according to any one of claims 1 to 5.

7. The specified period is selected from the range of 30 seconds to 90 seconds. The switch device according to any one of claims 1 to 5.

8. The predetermined number of times is once or twice. The switch device according to any one of claims 1 to 5.

9. The control unit outputs a signal notifying that an abnormality has occurred in the switch device when the number of times that the voltage equal to or greater than the first threshold value has been applied during the specified period exceeds a predetermined number of times. The switch device according to any one of claims 1 to 5.

10. The control unit has a voltage detection unit that detects a voltage applied to the first semiconductor switch, and determines whether a voltage equal to or greater than the first threshold value is applied to the first semiconductor switch based on a detected voltage detected by the voltage detection unit. The switch device according to any one of claims 1 to 5.

11. The voltage detection unit is connected to one end of the first semiconductor switch via a first rectifier element, and is connected to the other end of the first semiconductor switch via a second rectifier element. The switch device according to claim 10.

12. A switch device according to any one of claims 1 to 5, The load connected to the switch device; A load control system comprising:

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