Power switching module

Abstract

To provide a power switching module that can prevent an increase in the temperature of a power switch.SOLUTION: The present power switching module comprises: an electric circuit that connects a power supply and a load to each other; a power switch that switches between a conduction state and a non-conduction state of the electric circuit by switching of a mechanical contact; and a control unit that receives an on-command from a host device, and when the time elapsed from when the power switch is switched to the non-conduction state is equal to or more than a predetermined time, switches the power switch to the conduction state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power switching module. [Background technology]

[0002] Conventionally, there have been proposed devices that monitor the temperature rise of an electrical appliance such as a relay and determine whether or not to stop the operation depending on whether or not an abnormality has occurred. For example, Patent Document 1 discloses a device that is provided with a temperature measurement module that measures the temperature of the electrical appliance, and determines whether or not an abnormality has occurred in the electrical appliance based on the temperature measurement result and the current measurement result. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-68855 Summary of the Invention [Problem to be solved by the invention]

[0004] In a relay, if the contacts are turned on in a short period of time after being turned off, the contacts may become hot. To dissipate the heat from the hot contacts, adding heat dissipation components can be considered, but adding heat dissipation components can be an obstacle to making the device smaller and cheaper.

[0005] An object of one aspect of the disclosed technology is to provide a power switching module that can suppress a temperature rise in a power switch. [Means for solving the problem]

[0006] One aspect of the disclosed technology is exemplified by the following power switching module: The power switching module includes an electric circuit connecting a power source and a load, a power switch provided in the electric circuit and switching between a conductive state and a non-conductive state of the electric circuit by switching a mechanical contact, and a control unit that receives an on command from a higher-level device and switches the power switch to the conductive state when a predetermined time or more has elapsed since the power switch was switched to the non-conductive state.

[0007] Even when the power switching module receives the ON command, it does not switch the power switch to the conductive state until the predetermined time has elapsed since the power switch was turned OFF. This prevents the power switch from being turned ON in a short period of time. This power switching module can therefore prevent the power switch from being turned ON in a short period of time without using a heat dissipation component such as a heat sink. Here, the power switch may be a relay.

[0008] The power switching module may further include the following feature. The control unit acquires the temperature of the power switch, and if the acquired temperature is equal to or less than the temperature threshold, places the power switch in the conductive state in response to the ON command, even if the elapsed time is less than the predetermined time. If the temperature is equal to or less than the predetermined temperature threshold, it is considered that a temperature rise in the power switch is suppressed even if the power switch is placed in the conductive state. In a power switching module having such features, if the temperature is equal to or less than the temperature threshold, the power switch is placed in the conductive state in response to the ON command, even if the predetermined time has not elapsed. Therefore, the power switching module suppresses a temperature rise in the power switch, and shortens the time from the ON command until the power switch is placed in the conductive state when the temperature is equal to or less than the temperature threshold.

[0009] The control unit acquires a current value of a current flowing through the electrical path, and the acquired current value is set to a predetermined value. If the current value is equal to or less than the current threshold, the power switch is brought into the conductive state in response to the ON command even if the elapsed time is less than the predetermined time. If the current value is equal to or less than the current threshold, it is believed that even if the power switch is brought into the conductive state, a temperature rise in the power switch is suppressed. In a power switching module having such characteristics, if the current value is equal to or less than the current threshold, the power switch is brought into the conductive state in response to the ON command even if the predetermined time has not elapsed. Therefore, this power switching module reduces the time from the ON command until the power switch is brought into the conductive state when the current value is equal to or less than the temperature threshold, while suppressing a temperature rise in the power switch. [Effects of the Invention]

[0010] According to the disclosed technology, the power switching module can suppress the temperature rise of the power switch. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a charging system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a change in temperature of the contacts of the relay when the relay is switched on and off. [Figure 3] FIG. 3 is a diagram illustrating an example of a processing block of the control unit according to the embodiment. [Figure 4] FIG. 4 is a first diagram schematically showing the timing at which the relay is turned on in response to an on command in this embodiment. [Figure 5] FIG. 5 is a second diagram schematically showing the timing at which the relay is turned on in response to an on command in this embodiment. [Figure 6] FIG. 6 is a third diagram schematically showing the timing at which the relay is turned on in response to an on command in this embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of a processing flow of the control unit in the embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of a charging system according to a first modified example. [Figure 9] FIG. 9 is a diagram illustrating an example of a processing block of a control unit according to the first modified example. [Figure 10] FIG. 10 is a diagram illustrating an example of a processing flow of the control unit in the first modified example. [Figure 11] FIG. 11 is a diagram showing an example of a charging system according to a second modification. [Figure 12] FIG. 12 is a diagram illustrating an example of a processing block of a control unit according to the second modified example. [Figure 13] FIG. 13 is a diagram illustrating an example of a processing flow of the control unit in the second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Application example> An application example of the present invention will be described below. An example of the application of the present invention is a power switching module 200 as shown in Fig. 1. In the power switching module 200, a storage battery of an EV 230 connected to an outlet 220 is charged with power supplied from an AC power source 210 via an electrical path PL1.

[0013] In the power switching module 200, a relay 21 is disposed on the electric circuit PL1. The relay 21 switches the electric circuit PL1 between a conductive state and a non-conductive state. When the relay 21 is turned on, the electric circuit PL1 is in a conductive state. When the relay 21 is turned off, the electric circuit PL1 is in a non-conductive state. Here, the temperature of the relay 21 is likely to rise if the relay 21 is turned on and off in a short period of time. If the temperature of the relay 21 becomes too high, a heat dissipation design such as the addition of heat dissipation components will be required, making it difficult to reduce the size and cost of the power switching module 200.

[0014] Therefore, in this application example, the control unit 24 receives a relay-on command from the management system 250. However, if the time that has elapsed since the relay 21 was turned off is less than a predetermined time, the control unit 24 does not turn on the relay 21. That is, in this application example, the control unit 24 turns on the relay 21 when it receives a relay-on command from the management system 250 and the time that has elapsed since the relay 21 was turned off is equal to or greater than a predetermined time.

[0015] According to this application example, the relay 21 is not turned on while the elapsed time since the relay 21 was turned off is less than a predetermined time, thereby suppressing a temperature rise of the relay 21 caused by the relay 21 being turned on for a short period of time. Therefore, according to this application example, a temperature rise of the relay 21 can be suppressed without using a heat dissipation component such as a heat sink.

[0016] <Embodiment> Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an example of a charging system 300 according to an embodiment. The charging system 300 is a system that charges a storage battery of an EV 230 connected via an outlet 220 of a charging facility 260 with power supplied from an AC power source 210. The charging system 300 includes a management system 250, the charging facility 260, the AC power source 210, and a network NT1.

[0017] Charging equipment 260 includes power switching module 200 and outlet 220. Outlet 220 is a connection terminal to which EV 230 is connected. Power switching module 200 is provided between AC power source 210 and outlet 220, which are connected by electrical circuit PL1. Power switching module 200 opens and closes electrical circuit PL1, and controls charging of the storage battery of EV 230 from AC power source 210.

[0018] The power switching module 200 includes a relay 21, a measuring unit 22, a communication unit 23, and a control unit 24. The relay 21 opens and closes an electric circuit PL1 that connects an AC power source 210 and an outlet 220. The relay 21 switches the electric circuit PL1 between a conductive state and a non-conductive state, for example, by opening and closing a mechanical contact. When the relay 21 is turned on, the contact closes and the electric circuit PL1 enters a conductive state. When the relay 21 is turned off, the contact opens and the electric circuit PL1 enters a non-conductive state.

[0019] Measurement unit 22 is, for example, a device that is disposed on electric line PL1 that supplies AC power from AC power supply 210 to EV 230, and measures the power or amount of power supplied from AC power supply 210 to EV 230.

[0020] The communication unit 23 is an interface that transmits and receives information between the power switching module 200 and the management system 250 using a predetermined communication method. The control unit 24 includes a processor such as an MPU and a memory, and performs overall control of the relay 21, the measurement unit 22, and the communication unit 23. The control unit 24 controls the relay 21 in response to, for example, a relay-on command and a relay-off command from the management system 250. The control unit 24 also transmits the power or amount of power measured by the measurement unit 22 to the management system 250 via the communication unit 23.

[0021] <About the characteristics of Relay 21> FIG. 2 is a diagram illustrating an example of a change in temperature of the contacts of the relay 21 when the relay 21 is switched on and off. The vertical axis of FIG. 2 illustrates temperature, and the horizontal axis illustrates time. In FIG. 2, the relay 21 is turned on at the timing indicated by the arrow, and the on state continues for five seconds, after which the relay 21 is turned off. Referring to FIG. 2, it can be seen that the temperature of the contacts of the relay 21 often rises when the relay 21 is turned on and off in a short period of time.

[0022] <Processing blocks of the control unit 24> 3 is a diagram illustrating an example of a processing block of the control unit 24 according to the embodiment. The control unit 24 includes a measurement unit 241 and an instruction unit 242. The control unit 24 executes the processes of the measurement unit 241, instruction unit 242, and other units by causing a processor such as an MPU to execute a computer program deployed in a memory.

[0023] The measurement unit 241 measures the time that has elapsed since the relay 21 was turned off. The measurement unit 241 resets the measurement of the elapsed time when the relay 21 is turned on, and resumes the measurement of the elapsed time when the relay 21 is turned off again.

[0024] For example, when the instructing unit 242 receives a relay-on command from the management system 250 to turn on the relay 21, the instructing unit 242 closes the contacts of the relay 21 and brings the electrical circuit PL1 into a conductive state after the elapsed time measured by the measuring unit 241 reaches or exceeds a predetermined time. The predetermined time is determined as appropriate based on, for example, the period until the temperature of the relay 21, which has risen after being turned on, drops to a certain level. The predetermined time is, for example, one minute. The predetermined time may also be determined as appropriate between 30 seconds and one minute and 30 seconds.

[0025] 4 to 6 are diagrams schematically showing the timing at which the relay 21 is turned on in response to an ON command in this embodiment. The timing at which the relay 21 is turned on in response to an ON command will be described below with reference to FIGS. 4 to 6.

[0026] 4 illustrates a case where an ON command is received at time T1, when the time that has elapsed since relay 21 was turned off is less than a predetermined time. Instructor 242 does not turn on relay 21 at time T1 because the time that has elapsed since relay 21 was turned off, time T0, to time T1, when the ON command is received, is less than the predetermined time from time T0. Instructor 242 turns on relay 21 at time T2, when the time that has elapsed since time T0 is equal to or greater than the predetermined time.

[0027] 5 illustrates a case where an ON command is received at time T4, when the time elapsed since charging equipment 260 was powered on is less than a predetermined time. In the example of FIG. 5, when charging equipment 260 is powered on, relay 21 is assumed to be OFF. Instructor 242 does not turn on relay 21 at time T4 because the time elapsed from time T3, when charging equipment 260 is powered on, to time T4, when the ON command is received, is less than the predetermined time from time T3. Instructor 242 turns on relay 21 at time T5, when the time elapsed since time T3 is equal to or greater than the predetermined time.

[0028] 6 illustrates a case where an ON command is received at time T7, when the time elapsed since charging equipment 260 was powered on is equal to or longer than a predetermined time. In the example of FIG. 6, when charging equipment 260 is powered on, relay 21 is assumed to be OFF. Instructor 242 turns on relay 21 at time T7 because the time elapsed from time T6, when charging equipment 260 is powered on, to time T7, when the ON command is received, is equal to or longer than a predetermined time from time T6.

[0029] <Processing flow of the control unit 24> 7 is a diagram showing an example of a processing flow of the control unit 24 in the embodiment. Hereinafter, an example of the processing flow of the control unit 24 will be described with reference to FIG.

[0030] In step S1, relay 21 is turned off. Relay 21 is turned off, for example, by powering on charging facility 260. Relay 21 is also turned off in response to a relay-off command received from management system 250, for example.

[0031] In step S2, the measurement unit 241 starts measuring the time that has elapsed since the relay 21 was turned off in step S1.

[0032] In step S3, the instruction unit 242 determines whether or not a relay-on command has been received from the management system 250. If a relay-on command has been received (YES in step S3), the process proceeds to step S4. If a relay-on command has not been received (NO in step S3), the process of step S3 is repeated.

[0033] In step S4, the instruction unit 242 determines whether the time that has elapsed since the relay 21 was turned off is equal to or greater than a predetermined time. If it is equal to or greater than the predetermined time (YES in step S4), the process proceeds to step S6. If it is less than the predetermined time (NO in step S4), the process proceeds to step S5.

[0034] In step S5, the instruction unit 242 waits until the elapsed time since the measurement was started in step S2 reaches a predetermined time.

[0035] In step S6, the instruction unit 242 turns on the relay 21 to bring the electrical line PL1 into a conductive state.

[0036] <Effects of the embodiment> In this embodiment, even if a relay-on command is received from the management system 250, the relay 21 is not turned on until a predetermined time has elapsed since the relay 21 was turned off. This prevents the relay 21 from rising in temperature due to being turned on for a short period of time. Therefore, according to this embodiment, the temperature rise of the relay 21 can be prevented without using a heat dissipation component such as a heat sink.

[0037] In this embodiment, the measurement of the predetermined time period starts when the relay 21 is turned off. Therefore, the time from when the relay-on command is received until the relay 21 is actually turned on can be shortened compared to when the measurement of the predetermined time period starts when the relay-on command is received.

[0038] <First Modification> In the embodiment, the relay 21 is not turned on until a predetermined time has elapsed since the relay 21 was turned off, regardless of the temperature of the relay 21. In the first modified example, a configuration will be described in which, if the temperature of the relay 21 is equal to or lower than a predetermined temperature threshold, the relay 21 is turned on even if the predetermined time has not elapsed since the relay 21 was turned off. Components common to the embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted. The first modified example will be described below with reference to the drawings.

[0039] 8 is a diagram showing an example of a charging system 300A according to a first modification. The charging system 300A differs from the charging system 300 according to the embodiment in that the charging system 300A includes a charging facility 260A. The charging facility 260A also differs from the charging system 300 according to the embodiment in that the charging facility 260A includes a thermometer 25 and a control unit 24A.

[0040] The thermometer 25 measures the temperature of the relay 21. The thermometer 25 measures, for example, the temperature of the contact of the relay 21. The temperature measured by the thermometer 25 is acquired by the control unit 24A.

[0041] Based on the temperature acquired from the thermometer 25, the control unit 24A switches whether or not to turn on the relay 21 immediately after receiving the relay-on command.

[0042] 9 is a diagram showing an example of a processing block of a control unit 24A according to Modification 1. The control unit 24A differs from the control unit 24 according to the embodiment in that it includes an instruction unit 242A.

[0043] When the temperature acquired from the thermometer 25 is equal to or lower than a predetermined temperature threshold, the indicator 242A Even if the elapsed time measured by the measuring unit 241 is less than the predetermined time, the relay 21 is turned on in response to the relay-on command. The temperature threshold value is, for example, stored in advance in the memory of the control unit 24A. The temperature threshold value is also determined appropriately taking into consideration the temperature rise of the relay 21 after the relay 21 is turned on.

[0044] 10 is a diagram showing an example of a processing flow of the control unit 24A in the first modified example. Hereinafter, an example of a processing flow of the control unit 24A will be described with reference to FIG.

[0045] In step S11, the instruction unit 242A determines whether the temperature measured by the thermometer 25 is equal to or lower than the temperature threshold. If it is equal to or lower than the temperature threshold (YES in step S11), the process proceeds to step S6. If it is higher than the temperature threshold (NO in step S11), the process proceeds to step S4.

[0046] If the temperature before relay 21 is turned on is high, there is a risk that the temperature of relay 21 after it is turned on will be outside the allowable range. According to the first modification, if the temperature measured by thermometer 25 is equal to or lower than the temperature threshold, relay 21 is turned on in response to a relay-on command even if a predetermined time has not elapsed since relay 21 was turned off. Therefore, according to the first modification, the temperature rise of relay 21 is suppressed, and the time from the relay-on command to relay 21 being turned on is shortened when the temperature measured by thermometer 25 is equal to or lower than the temperature threshold.

[0047] <Second Modification> In the embodiment, the relay 21 is not turned on until a predetermined time has elapsed since the relay 21 was turned off, regardless of the current value of the current flowing through the electric circuit PL1. In the second modified example, a configuration will be described in which the relay 21 is turned on even if the predetermined time has not elapsed since the relay 21 was turned off, when the current value of the current flowing through the electric circuit PL1 is equal to or less than a predetermined current threshold. Components common to the embodiment will be assigned the same reference numerals, and their description will be omitted. The second modified example will be described below with reference to the drawings.

[0048] 11 is a diagram showing an example of a charging system 300B according to a second modification. The charging system 300B differs from the charging system 300 according to the embodiment in that it includes a charging facility 260B. The charging facility 260B also differs from the charging system 300 according to the embodiment in that it includes an ammeter 26 and a control unit 24B.

[0049] The ammeter 26 measures the current value of the current flowing through the relay 21 when the relay 21 is turned on. The current value measured by the ammeter 26 is acquired by the control unit 24B.

[0050] The control unit 24B stores the current value acquired from the ammeter 26 in memory. The control unit 24B acquires the current value from the ammeter 26 and stores the acquired current value in memory every time the relay 21 is turned on. The control unit 24B switches whether or not to turn on the relay 21 immediately upon receiving a relay-on command, based on the current value when the relay 21 was last turned on.

[0051] 12 is a diagram showing an example of a processing block of a control unit 24B according to Modification 2. The control unit 24B differs from the control unit 24 according to the embodiment in that it includes an instruction unit 242B.

[0052] The instruction unit 242B stores the current value acquired from the ammeter 26 in memory. If the current value stored in the memory is equal to or less than the current threshold, the instruction unit 242B turns on the relay 21 in response to the relay-on command, even if the elapsed time measured by the measurement unit 241 is less than the predetermined time. The current threshold is stored in advance in the memory of the control unit 24B, for example. The current threshold is also determined appropriately taking into consideration the temperature rise of the relay 21 after the relay 21 is turned on.

[0053] 13 is a diagram showing an example of a processing flow of the control unit 24B in Modification 2. Hereinafter, an example of a processing flow of the control unit 24B will be described with reference to FIG.

[0054] In step S21, instruction unit 242B determines whether the current value stored in memory is equal to or less than the current threshold. If it is equal to or less than the current threshold (YES in step S21), the process proceeds to step S6A. If it is higher than the current threshold (NO in step S21), the process proceeds to step S4.

[0055] In step S6A, the instruction unit 242B turns on the relay 21 to bring the electric circuit PL1 into a conductive state. The instruction unit 242B further acquires from the ammeter 26 the value of the current flowing through the relay 21 in the on state of the relay 21, and stores the value in the memory.

[0056] When a large current flows through the relay 21, the temperature of the relay 21 is likely to rise. Therefore, when the current value of the current flowing through the relay 21 is equal to or less than the current threshold, it is considered that the temperature rise of the relay 21 is suppressed even when the relay 21 is turned on. According to the second modification, when the current value measured by the ammeter 26 is equal to or less than the current threshold, the relay 21 is turned on in response to the relay-on command even if a predetermined time has not elapsed since the relay 21 was turned off. Therefore, according to the second modification, the temperature rise of the relay 21 is suppressed while the time from the relay-on command to the relay 21 being turned on is shortened when the current value of the current flowing through the relay 21 is equal to or less than the current threshold.

[0057] The embodiments and modifications disclosed above can be combined with each other.

[0058] <Appendix 1> an electric circuit (PL1) connecting the power source (210) and the load (230); a power switch (21) provided in the electric circuit (PL1) and configured to switch between a conductive state and a non-conductive state of the electric circuit (PL1) by switching a mechanical contact; a control unit (24, 24A, 24B) that receives an ON command from a higher-level device (250) and switches the power switch (21) to the conductive state when a predetermined time or more has elapsed since the power switch (21) was switched to the non-conductive state, Power switching module (200, 200A, 200B). <Appendix 2> the control unit (24A) acquires a temperature of the power switch (21), and when the acquired temperature is equal to or lower than a predetermined temperature threshold, the control unit (24A) brings the power switch (21) into the conductive state in response to the ON command even if the elapsed time is less than the predetermined time. 2. The power switching module (200A) according to claim 1. <Appendix 3> the control unit (24B) acquires a current value of a current flowing through the electric circuit (PL1), and when the acquired current value is equal to or less than a predetermined current threshold, the control unit (24B) brings the power switch (21) into the conductive state in response to the ON command even if the elapsed time is less than the predetermined time. 2. The power switching module (200B) according to claim 1. <Appendix 4> The power switch (21) is a relay. 4. The power switching module (200, 200A, 200B) according to any one of claims 1 to 3.

[0059] 21 Relay 22...Measuring part 23. Communications Department 24 Control Unit 24A··Control unit 24B··Control unit 25...Thermometer 26...Ammeter 200 Power Switching Module 210 AC power supply 220··Outlet 230 EV 241··Measurement section 242·Instruction section 242A·Instruction section 242B··Instruction section 250··Management System 260·Charging equipment 260A·Charging equipment 260B·Charging equipment 300··Charging System 300A charging system NT1 Network PL1·Electric circuit

Claims

1. an electric circuit connecting the power source and the load; a power switch provided in the electric circuit and configured to switch between a conductive state and a non-conductive state of the electric circuit by switching a mechanical contact; a control unit that receives an on command from a higher-level device and switches the power switch to the conductive state when a predetermined time or more has elapsed since the power switch was switched to the non-conductive state, Power switching module.

2. the control unit acquires a temperature of the power switch, and when the acquired temperature is equal to or lower than a predetermined temperature threshold, the control unit places the power switch in the conductive state in response to the ON command even if the elapsed time is less than the predetermined time. The power switching module according to claim 1 .

3. the control unit acquires a current value of the current flowing through the electric circuit, and when the acquired current value is equal to or less than a predetermined current threshold, brings the power switch into the conductive state in response to the ON command even if the elapsed time is less than the predetermined time. The power switching module according to claim 1 .

4. The power switch is a relay.

4. The power switching module according to claim 1.

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