Control device, semiconductor shutdown system, control method for semiconductor switch, control program, and recording medium

Abstract

To provide a control device, etc. that can suppress the generation of surge voltage regardless of a load connected to a semiconductor switch.SOLUTION: A control device (3) comprises a detection current inclination acquisition unit (31) that acquires temporal changes in the detection current as the inclination of the detection current, and an open / close control unit (32) that performs open / close control of a semiconductor switch (2) using the results obtained by the detection current inclination acquisition unit (31).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a control device for a semiconductor switch that performs an interruption operation. [Background technology]

[0002] In recent years, semiconductor interruption systems equipped with semiconductor switches have been used in power systems that supply power from a power source to a load. When an overcurrent flows through the semiconductor switch in the event of a short circuit accident on the load side, for example, the semiconductor interruption system operates the semiconductor switch to quickly interrupt the power.

[0003] A conventional semiconductor switch control device is disclosed that includes a gate voltage pattern generator that generates a pattern voltage in which the voltage change rate of the voltage applied to the gate electrode of the semiconductor switch is changed during a period from the start to the end of the semiconductor switch's cut-off operation, and a gate voltage drive amplifier that drives the semiconductor switch to turn off in accordance with the pattern voltage (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-150462 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional semiconductor switch control device as described above, there has been a problem in that the occurrence of a surge voltage cannot be suppressed depending on the load connected to the semiconductor switch.

[0006] The present disclosure has been made in consideration of the above problems, and aims to provide a control device and the like that can suppress the occurrence of surge voltage regardless of the load connected to a semiconductor switch. [Means for solving the problem]

[0007] In order to solve the above problems, a control device according to one aspect of the present disclosure is a semiconductor system including a semiconductor switch having one end connected to a power source and the other end connected to a load, and cutting off a current from the power source to the load, and a current sensor detecting a current flowing from the power source to the semiconductor switch, the control device controlling the semiconductor switch including a detected current slope acquisition unit that determines a change over time in the detected current detected by the current sensor and acquires the determined change over time in the detected current as a slope of the detected current, and an opening / closing control unit that uses the result acquired by the detected current slope acquisition unit to control the opening and closing of the semiconductor switch.

[0008] Moreover, a semiconductor interruption system according to one aspect of the present disclosure includes a semiconductor switch having one end connected to a power source and the other end connected to a load, which interrupts a current from the power source to the load, a current sensor which detects a current flowing from the power source to the semiconductor switch, and the above-mentioned control device.

[0009] Moreover, a control method for a semiconductor switch according to one aspect of the present disclosure is a control method for controlling a semiconductor switch in a semiconductor system including a semiconductor switch having one end connected to a power source and the other end connected to a load, and cutting off a current from the power source to the load, and a current sensor detecting a current flowing from the power source to the semiconductor switch, the control method including a detected current slope acquisition step of determining a change over time in the detected current detected by the current sensor and acquiring the determined change over time in the detected current as a slope of the detected current, and an opening / closing control step of controlling the opening and closing of the semiconductor switch using a result acquired in the detected current slope acquisition step.

[0010] In addition, the control device according to one aspect of the present disclosure may be realized by a computer. In this case, the control program of the control device that realizes the control device on a computer by causing the computer to operate as each part (software element) of the control device, and the computer-readable recording medium on which it is recorded, also fall within the scope of the present disclosure. Effect of the Invention

[0011] According to one aspect of the present disclosure, it is possible to provide a control device and the like that can suppress the occurrence of a surge voltage regardless of the load connected to a semiconductor switch. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram showing a control device according to an embodiment of the present disclosure and a semiconductor shutdown system including the control device; [Diagram 2] 2 is a diagram for explaining a specific example of the configuration of a driver shown in FIG. 1; [Diagram 3] 5 is a flowchart showing an example of the operation of the control device. [Figure 4] 2 is a waveform diagram illustrating the relationship between the time change of a passing current (detection current) in the semiconductor switch shown in FIG. 1 and N pieces. FIG. [Diagram 5] 11 is a table showing the relationship between the number N and the gradient of the detected current. [Figure 6] 5 is a waveform diagram showing a specific change in voltage applied to a gate electrode of the semiconductor switch in the control device. FIG. [Figure 7] 4 is a diagram for explaining a specific example of the voltage and application time applied to each of the N gate electrodes. FIG. [Figure 8] FIG. 4 is a waveform diagram illustrating an example of the operation of the control device. [Figure 9] FIG. 11 is a waveform diagram illustrating another example of the operation of the control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [Embodiment] Hereinafter, one embodiment of the present disclosure will be described in detail.

[0014] (Configuration of power system to which semiconductor circuit breaker system 1 is applied) Fig. 1 is a schematic diagram showing a control device 3 according to an embodiment of the present disclosure and a semiconductor interruption system 1 including the control device. As shown in Fig. 1, the semiconductor interruption system 1 of this embodiment is electrically connected to a power source 51 on its input side and to a load 52 on its output side. In the following description, a case in which the semiconductor interruption system 1 of this embodiment is applied to a DC power system K will be described as an example.

[0015] The semiconductor interruption system 1 of this embodiment is a system that appropriately interrupts DC power from the power source 51 side, and the semiconductor interruption system 1 is a semiconductor circuit breaker that interrupts a current from the power source 51 to the load 52. The power source 51 is not limited to a DC power source, and may be an AC power source. However, when the power source 51 is an AC power source, an AC-DC converter is installed between the power source 51 and the semiconductor interruption system 1, and the AC power from the power source 51 is converted into DC power by the AC-DC converter and then supplied to the semiconductor interruption system 1.

[0016] The load 52 is a device that operates on DC power. The load 52 has an LC filter consisting of a capacitor and a coil on its input side, and is configured to stabilize the input power and take measures against noise. The load 52 also has a power storage device such as a capacitor on its input side, and the power storage device is configured to compensate for the operating voltage when the supply of DC power is interrupted momentarily. In addition to the above description, the load 52 that operates on AC power can be used. In this case, for example, a DC-AC converter that converts the DC power from the semiconductor interruption system 1 into AC power is installed inside the load 52.

[0017] (Configuration of semiconductor shutdown system 1) 1, the semiconductor interruption system 1 of the present embodiment includes a first line L1, a second line L2, a semiconductor switch 2, a control device 3, and a current sensor 4. The first line L1 connects a positive electrode (not shown) of a power source 51 and a load 52. The second line L2 connects a negative electrode (not shown) of the power source 51 and the load 52. The first line L1 and the second line L2 respectively constitute a part of a main line and a return line of a DC power system K.

[0018] The semiconductor switch 2 is located between a power source 51 and a load 52 on the first line 11, with one end connected to the power source 51 and the other end connected to the load 52. The semiconductor switch 2 includes a semiconductor switch body 21 and a parasitic diode 22 formed in the semiconductor switch body 21. The control device 3 controls the semiconductor switch 2 using the detection result of the current sensor 4 and a cutoff operation region (FIGS. 4 and 5 shown below) that is preset in the control device 3 (details will be described later).

[0019] Furthermore, since the other end of the semiconductor switch 2 is connected to the load 52, when DC power is supplied from the power source 51 to the load 52 via the semiconductor switch 2, an inrush current may flow to the load 52. That is, since the load 52 is provided with a power storage device as described above, the load 52 has a capacitance component when viewed from the power source 51. Therefore, when DC power is supplied, an inrush current, which is an excessive charging current to the power storage device of the load 52, may flow from the power source 51 via the semiconductor interruption system 1.

[0020] 1, the current sensor 4 is provided between the power supply 51 and the semiconductor switch 2. The current sensor 4 is configured using an ammeter such as a known current transformer, and detects the current flowing from the power supply 51 to the semiconductor switch 2 (i.e., the passing current passing through the semiconductor switch 2 toward the load 52) as a detection current. The current sensor 4 outputs the detection result (the value of the detected current) to the control device 3.

[0021] The semiconductor switch 2 may be, for example, a bipolar transistor, a metal-oxide-semiconductor field-effect transistor (MOSFET), or an insulated gate bipolar transistor (IGBT).

[0022] (Configuration of control device 3) The control device 3 includes a detected current gradient acquiring unit 31, an opening / closing control unit 32, a driver 33, and a storage unit 34. The control device 3 controls the semiconductor switch 2 by outputting an instruction signal to the semiconductor switch body 21. In other words, the control device 3 controls the semiconductor switch 2 by applying a voltage as the instruction signal to a gate electrode 21g (hereinafter referred to as the gate electrode 21g of the semiconductor switch 2) included in the semiconductor switch body 21.

[0023] Specifically, when the control device 3 performs a cutoff operation of the semiconductor switch 2, the control device 3 selects one of the N predetermined cutoff operation regions (N is an integer equal to or greater than 2) based on the slope of a detected current described below. Then, the control device 3 generates an instruction signal to be output to the gate electrode 21g (FIG. 2) of the semiconductor switch 2 based on gate voltage change information predetermined in accordance with the selected cutoff operation region. Then, the control device 3 controls the semiconductor switch 2 by outputting the generated instruction signal from the driver 33 to the gate electrode 21g.

[0024] The detected current slope acquisition unit 31 obtains a change over time in the detected current detected by the current sensor 4, and acquires the obtained change over time in the detected current as a slope of the detected current. The detected current slope acquisition unit 31 outputs the obtained slope of the detected current to the opening / closing control unit 32.

[0025] In the above description, the detected current slope acquisition unit 31 always acquires the slope of the detected current when the semiconductor switch 2 is in an ON state (i.e., when the semiconductor switch 2 is in an ON state and current is permitted to flow from the power source 51 to the load 52). However, the present disclosure is not limited to this. For example, the detected current slope acquisition unit 31 may acquire the slope of the detected current only when a shutoff determination processing unit 32a (to be described later) of the opening / closing control unit 32 determines that the semiconductor switch 2 needs to be shut off.

[0026] The switching control unit 32 includes a cutoff determination processing unit 32a, a cutoff operation selection unit 32b, and a cutoff operation execution unit 32c. The cutoff determination processing unit 32a compares the detected current detected by the current sensor 4 with a predetermined overcurrent threshold to determine whether or not a cutoff operation of the semiconductor switch 2 is required. The cutoff operation selection unit 32b selects one cutoff operation region from N predetermined cutoff operation regions based on the result of acquisition of the slope of the detected current from the detected current slope acquisition unit 31. The cutoff operation execution unit 32c causes the semiconductor switch 2 to execute a cutoff operation corresponding to the cutoff operation region selected by the cutoff operation selection unit 32b.

[0027] Specifically, the cutoff operation executing unit 32c creates the instruction signal for each of the N cutoff operation regions based on predetermined gate voltage change information (FIG. 7) and outputs it to the gate electrode 21g of the semiconductor switch 2, thereby controlling the gate electrode 21g to cause the semiconductor switch 2 to perform a cutoff operation. As will be described later in detail, the gate voltage change information includes multiple sets of change information each consisting of a voltage applied to the gate electrode 21g and an application time for that voltage.

[0028] Furthermore, when the interruption operation execution unit 32c determines, based on the detection result from the current sensor 4, that the detected current passing through the semiconductor switch 2 and flowing toward the load 52 has become zero, it terminates the interruption operation of the semiconductor switch 2. As a result, in this embodiment, the interruption operation of the semiconductor switch 2 can be appropriately terminated, making it possible to accurately control the semiconductor switch 2. In addition to this description, the interruption operation execution unit 32c may terminate the interruption operation of the semiconductor switch 2 when the interruption determination processing unit 32a determines that the detected current has become zero.

[0029] Here, the driver 33 will be specifically described with reference to Fig. 2. Fig. 2 is a diagram for explaining a specific example of the configuration of the driver 33 shown in Fig. 1.

[0030] The driver 33 includes a DAC (Digital Analog Converter) 33a, a buffer circuit 33b, and a gate resistor 33c. The DAC 33a performs digital-to-analog conversion on an instruction signal from the cutoff operation execution unit 32c of the switching control unit 32 to generate an analog instruction signal (voltage signal) and outputs it to the buffer circuit 33b. The buffer circuit 33b performs a predetermined voltage correction on the instruction signal from the DAC 33a and outputs it to the gate resistor 33c.

[0031] The gate resistor 33c has a predetermined resistance to prevent malfunction of the semiconductor switch 2, and appropriately reduces the voltage value of the voltage signal from the buffer circuit 33b and supplies the reduced voltage signal to the gate electrode 21g. In this manner, the driver 33 drives the semiconductor switch 2 based on the instruction signal from the opening / closing control unit 32.

[0032] The storage unit 34 is configured using, for example, a rewritable non-volatile memory, and is capable of storing a control program that controls each part of the control device 3. The storage unit 34 also stores in advance the overcurrent threshold value, the N cutoff operation regions, and the gate voltage change information.

[0033] (Operation of control device 3) Next, an example of the operation of the control device 3 of this embodiment will be specifically described with reference to Figs. 3 to 7. Fig. 3 is a flowchart showing an example of the operation of the control device 3. Fig. 4 is a waveform diagram explaining the relationship between the time change of the passing current (detection current) in the semiconductor switch 2 shown in Fig. 1 and the number of N. Fig. 5 is a table showing the relationship between the number of N and the slope of the detection current. Fig. 6 is a waveform diagram showing a specific change in the voltage applied to the gate electrode 21g of the semiconductor switch 2 in the control device 3. Fig. 7 is a diagram explaining a specific example of the voltage and application time applied to the gate electrode 21g for each of the N.

[0034] 3, in the control device 3, the detected current slope acquisition unit 31 acquires the slope of the detected current based on the detection result of the current sensor 4. In other words, the detected current slope acquisition unit 31 performs a detected current slope acquisition step of calculating a time change (did / dt) of the detected current detected by the current sensor 4 and acquiring the calculated time change of the detected current as the slope (did_set / dt) of the detected current. Then, in the control device 3, the detected current slope acquisition unit 31 outputs the acquired detected current slope to the switching control unit 32. As a result, in the control device 3, the switching control unit 32 performs an opening and closing control step of controlling the opening and closing of the semiconductor switch 2 by using the acquisition result of the detected current slope acquisition step.

[0035] Specifically, first, as shown in step S2, in the control device 3, the interruption determination processing unit 32a determines whether or not the passing current passing through the semiconductor switch 2 is an overcurrent, based on the detection result of the current sensor 4. In other words, the interruption determination processing unit 32a performs an interruption determination step of determining whether or not an interruption operation of the semiconductor switch 2 is required by comparing the detected current detected by the current sensor 4 with a predetermined overcurrent threshold value.

[0036] When the interruption determination processing unit 32a determines that the value of the detected current from the current sensor 4 is smaller than the overcurrent threshold value stored in the memory unit 34 (NO in step S2), the interruption determination processing unit 32a determines that it is not necessary to open the semiconductor switch 2, and returns to step S1. In other words, the opening and closing control unit 32 determines that an interruption operation of the semiconductor switch 2 is not necessary, and maintains the semiconductor switch 2 in the on state (closed conductive state).

[0037] On the other hand, when the interruption determination processing unit 32a determines that the value of the detected current from the current sensor 4 is equal to or greater than the overcurrent threshold value stored in the memory unit 34 (YES in step S2), the interruption determination processing unit 32a determines that the semiconductor switch 2 needs to be immediately opened, and proceeds to step S3. In other words, the opening and closing control unit 32 determines that an interruption operation is required in the semiconductor switch 2, and sets the semiconductor switch 2 to the OFF state (open state).

[0038] Next, as shown in step S3, in the control device 3, the cutoff operation selection unit 32b selects N values ​​of N corresponding to the slope (did_set / dt) of the detected current from the detected current slope acquisition unit 31. In other words, the cutoff operation selection unit 32b performs a selection step of selecting one of the N predetermined cutoff operation regions based on the acquisition result in the detected current slope acquisition step.

[0039] Here, in this embodiment, the N cutoff operation regions selected by the cutoff operation selection unit 32b will be specifically described. First, the slope (did_set / dt) of the detected current acquired by the detected current slope acquisition unit 31 will be specifically described with reference to Fig. 4. Next, the relationship between the slope (did_set / dt) of the detected current and the N cutoff operation regions will be specifically described with reference to Fig. 5.

[0040] 4, in the control device 3, the change in current per unit time (did / dt) that can be detected by the current sensor 4 is within a range indicated by a maximum value did_(1) / dt and a minimum value did_(k+1) / dt. In the control device 3, N cutoff operation regions into which the above region is divided are determined in advance and stored in the memory unit 34.

[0041] Specifically, in the control device 3, as shown in Figs. 4 and 5, when the slope (did_set / dt) of the detection current is equal to or less than the time change value did_(1) / dt and equal to or more than the time change value did_(2) / dt, the cutoff operation selection unit 32b selects the cutoff operation region with N value 1 from among the N cutoff operation regions. When the slope (did_set / dt) of the detection current is less than the time change value did_(2) / dt and equal to or more than the time change value did_(3) / dt, the cutoff operation selection unit 32b selects the cutoff operation region with N value 2 from among the N cutoff operation regions. When the slope (did_set / dt) of the detection current is less than the time change value did_(k) / dt and equal to or more than the time change value did_(k+1) / dt, the cutoff operation selection unit 32b selects the cutoff operation region with N value N from among the N cutoff operation regions.

[0042] In the control device 3 of this embodiment, the value of N is appropriately determined from values ​​equal to or greater than 2 by a user based on the magnitude of the breaking current in the semiconductor switch 2, and set in the storage unit 34. In other words, in the control device 3 of this embodiment, the upper limit of the value of N is determined based on the magnitude of the breaking current in the semiconductor switch 2.

[0043] In the control device 3 of this embodiment, the value of k in each of the N cutoff operation regions is an integer equal to or greater than 1, and is appropriately determined by the user according to the operation characteristics of the semiconductor switch 2, the output characteristics such as the power supply of the power source 51 connected to the semiconductor switch 2, and / or the load characteristics such as the power consumption of the load 52, and is stored in the storage unit 34. The value of k indicates the order of the cutoff operation in each of the N cutoff operation regions. Specifically, the value of k indicates the order in which the pulse width ts and the applied voltage VGS shown in FIG. 7 are set. The value of k is sequentially incremented by 1 according to the number of times the cutoff operation is performed (see step S7 in FIG. 3). Furthermore, the value of k can be set to the same value or different values ​​in each of the N cutoff operation regions.

[0044] Next, a specific example of the cutoff operation performed by the cutoff operation executing unit 32c using the gate voltage change information in this embodiment will be specifically described with reference to FIG.

[0045] As shown in FIG. 6, in the control device 3 of this embodiment, the shutoff operation execution unit 32c generates an instruction signal to be output to the driver 33 so that the applied voltage VGS to the gate electrode 21g is reduced in stages, and supplies the instruction signal to the driver 33.

[0046] Specifically, the cutoff operation execution unit 32c instructs the gate electrode 21g to apply a predetermined voltage between time 0 and time T1 as the instruction signal, and to supply an application voltage that is smaller than the predetermined application voltage by ΔVGS to the gate electrode 21g during a period ts from time T1 to time T2. Thereafter, the cutoff operation execution unit 32c instructs the gate electrode 21g to gradually reduce the application voltage during a period from time T2 to time T3 and a period from time T3 to time T4.

[0047] Moreover, the cutoff operation execution unit 32c is configured to perform a cutoff operation in the semiconductor switch 2 so that the voltage VGS applied to the gate electrode 21g is reduced stepwise, regardless of each of the N cutoff operation regions. However, in each cutoff operation region, the magnitude (the magnitude of the applied voltage that is reduced stepwise) and application time of the voltage applied to the gate electrode 21g are determined in advance as gate voltage change information including multiple sets of change information consisting of the voltage and application time applied to the gate electrode 21g for each cutoff operation region according to the cutoff characteristics of the semiconductor switch 2, and are stored in the storage unit 34.

[0048] Specifically, when the value of N is 1, the table shown in 701 of Fig. 7 is stored in advance in the storage unit 34 as gate voltage application information for the cutoff operation region where the value of N is 1. That is, according to this gate voltage application information, as shown in 701 of Fig. 7, during the period from the start of the cutoff operation to the application time ts_(11) specified by the pulse width ts, VGS_(11) is applied as the voltage applied to the gate electrode 21g. Thereafter, during the periods until the application time ts_(12), application time ts_(13), ..., and application time ts_(1k) have passed in sequence, VGS_(12), VGS_(13), ..., and VGS_(1k) with successively reduced magnitudes are applied as the voltage applied to the gate electrode 21g, respectively.

[0049] Similarly, when the value of N is 2, the table shown in 702 of Fig. 7 is stored in advance in the storage unit 34 as gate voltage application information for the cutoff operation region where the value of N is 2. That is, according to this gate voltage application information, as shown in 702 of Fig. 7, during the period from the start of the cutoff operation to the application time ts_(21) specified by the pulse width ts, VGS_(21) is applied as the voltage applied to the gate electrode 21g. Thereafter, during the periods until the application time ts_(22), application time ts_(23), ..., and application time ts_(2k) have passed in sequence, VGS_(22), VGS_(23), ..., and VGS_(2k), which are successively reduced in magnitude, are applied as the voltage applied to the gate electrode 21g, respectively.

[0050] Similarly, when the value of N is 3, the table shown in 703 of Fig. 7 is stored in advance in the storage unit 34 as gate voltage application information for the cutoff operation region where the value of N is 3. That is, according to this gate voltage application information, as shown in 703 of Fig. 7, during the period from the start of the cutoff operation to the application time ts_(31) specified by the pulse width ts, VGS_(31) is applied as the voltage applied to the gate electrode 21g. Thereafter, during the periods until the application time ts_(32), application time ts_(33), ..., and application time ts_(3k) have passed in sequence, VGS_(32), VGS_(33), ..., and VGS_(3k), which are successively reduced in magnitude, are applied as the voltage applied to the gate electrode 21g, respectively.

[0051] Similarly, when the value of N is N, the table shown in 704 of Fig. 7 is stored in advance in the storage unit 34 as gate voltage application information for the cutoff operation region where the value of N is N. That is, according to this gate voltage application information, as shown in 704 of Fig. 7, during the period from the start of the cutoff operation to the application time ts_(N1) specified by the pulse width ts, VGS_(N1) is applied as the voltage applied to the gate electrode 21g. Thereafter, during the periods until the application time ts_(N2), application time ts_(N3), ..., and application time ts_(Nk) have passed in sequence, VGS_(N2), VGS_(N3), ..., and VGS_(Nk) with successively reduced magnitudes are applied as the voltage applied to the gate electrode 21g, respectively.

[0052] In the above description, 701 to 704 in Fig. 7 are described in the case where the magnitude of the voltage applied to the gate electrode 21g is gradually reduced as shown in Fig. 6. However, the present disclosure is not limited to this, and the same applied voltage may be used in different application periods, or a voltage greater than the previous applied voltage may be used. In addition, the application times may be the same or different.

[0053] However, as described above, gradually reducing the magnitude of the voltage applied to the gate electrode 21g is preferable in terms of being able to reduce the surge voltage. Specifically, for example, if the magnitude of the applied voltage is suddenly reduced, the current supplied to the load 52, i.e., the change over time di / dt of the passing current, becomes high, and accordingly the value of the voltage VL (=L×di / dt, where L is the wiring inductance of the load 52) at the load 52 also becomes high. For this reason, the surge voltage may become higher than when the magnitude of the applied voltage is gradually reduced.

[0054] Returning to step S4 in FIG. 3, when the cutoff operation selection unit 32b selects, for example, a value of N as the value of N and selects that the slope of the detected current is in the cutoff operation region of N, the cutoff operation execution unit 32c determines that the corresponding cutoff operation region of N, that is, the table shown in 704 in FIG. 7, is to be applied to the current cutoff operation.

[0055] Next, the cutoff operation execution unit 32c initializes the value of k, that is, selects k=1 (step S5). Then, the cutoff operation execution unit 32c reads out gate voltage change information indicating the applied voltage and application time of k=1 by referring to the table shown in 704 of FIG. 7, which is stored in the storage unit 34. Specifically, the cutoff operation execution unit 32c reads out the application time ts_(N1) and the applied voltage VGS_(N1) from the storage unit 34. Then, the cutoff operation execution unit 32c creates an instruction signal based on the read application time ts_(N1) and applied voltage VGS_(N1), and causes the semiconductor switch 2 to perform a first cutoff operation via the driver 33 (step S6).

[0056] Next, the cutoff operation execution unit 32c adds 1 to the value of k (step S7). Specifically, the cutoff operation execution unit 32c selects k=2. Next, the cutoff operation execution unit 32c reads out gate voltage change information indicating the applied voltage and application time for k=2 by referring to the table shown in 704 of FIG. 7, which is stored in the storage unit 34. Specifically, the cutoff operation execution unit 32c reads out the application time ts_(N2) and the applied voltage VGS_(N2) from the storage unit 34. Then, the cutoff operation execution unit 32c creates an instruction signal based on the read application time ts_(N2) and applied voltage VGS_(N2), and causes the semiconductor switch 2 to perform a second cutoff operation via the driver 33 (step S8).

[0057] Next, the interruption determination processing unit 32a determines whether or not the passing current (detected current) flowing through the semiconductor switch 2 has become zero based on the detection result from the current sensor 4 (step S9). If the interruption determination processing unit 32a determines that the detected current has not become zero (NO in step S9), the interruption operation execution unit 32c returns to step S7 and continues the process, thereby causing the semiconductor switch 2 to execute the third and subsequent interruption operations.

[0058] On the other hand, when the cutoff determination processing unit 32a determines that the detected current is zero (YES in step S9), the cutoff operation execution unit 32c also determines that the detected current is zero, and applies the gate hold voltage VGS_min, which is the minimum value of the applied voltage VGS, as the applied voltage VGS to the gate electrode 21g (step S10). As a result, in this embodiment, the cutoff operation of the semiconductor switch 2 is terminated and the semiconductor switch 2 is opened.

[0059] Through the above steps S4 to S10, the control device 3 executes a cutoff operation execution step of causing the semiconductor switch 2 to execute a cutoff operation corresponding to the cutoff operation region selected in the selection step.

[0060] In the control device 3, the opening and closing control step includes a breaking determination step shown in step S2, a selection step shown in step S3, and a breaking operation execution step shown in steps S4 to S10.

[0061] Furthermore, as is clear from steps S6 to S9, the control device 3 of this embodiment performs the interruption operation at least two times, so that the effect of suppressing the surge voltage can be reliably achieved.

[0062] The control device 3 of this embodiment configured as described above includes a detected current slope acquisition unit 31 that determines the change over time of the detected current detected by the current sensor 4 and acquires the determined change over time of the detected current as the slope of the detected current, and an opening / closing control unit 32 that uses the result acquired by the detected current slope acquisition unit 31 to control the opening and closing of the semiconductor switch 2.

[0063] With the above configuration, in the control device 3 of this embodiment, the opening and closing control unit 32 sets the semiconductor switch 2 to an on or off state based on the slope of the detected current acquired by the detected current slope acquisition unit 31. As a result, in the control device 3 of this embodiment, the opening and closing control unit 32 can cause the semiconductor switch 2 to perform a cut-off operation in consideration of the detected current passing through the semiconductor switch 2 and flowing toward the load 52. As a result, unlike the conventional example, the control device 3 of this embodiment can appropriately cause the semiconductor switch 2 to perform a cut-off operation regardless of the load 52 connected to the semiconductor switch 2, thereby suppressing the occurrence of a surge voltage.

[0064] Furthermore, since the control device 3 of this embodiment can suppress the occurrence of surge voltage, the semiconductor shutoff system 1 using the control device 3 can omit the installation of a snubber circuit for suppressing surge voltage, for example. This makes it possible to easily configure a semiconductor shutoff system 1 that has a small number of parts, is inexpensive, and is compact.

[0065] In the control device 3 of this embodiment, the shutoff determination processing unit 32a is provided in the switching control unit 32, so that it is possible to appropriately determine whether or not a shutoff operation of the semiconductor switch 2 is required. As a result, the switching control unit 32 can appropriately control the opening and closing of the semiconductor switch 2.

[0066] Moreover, in the control device 3 of this embodiment, the switching control unit 32 is provided with the cutoff operation selection unit 32b and the cutoff operation execution unit 32c. This allows the switching control unit 32 to select one of N predetermined cutoff operation regions based on the result of acquisition of the slope of the detected current acquired by the detected current slope acquisition unit 31. Furthermore, the switching control unit 32 can cause the semiconductor switch 2 to execute a cutoff operation corresponding to the selected one cutoff operation region, making it possible to further suppress the occurrence of a surge voltage regardless of the load 52 connected to the semiconductor switch 2.

[0067] Furthermore, in the control device 3 of this embodiment, the N upper limit values ​​are determined based on the magnitude of the breaking current in the semiconductor switch 2, so that the N ranges can be appropriately determined based on the magnitude of the breaking current in the semiconductor switch 2. As a result, in the control device 3 of this embodiment, an appropriate breaking operation region can be reliably determined in accordance with the characteristics of the semiconductor switch 2, and the breaking operation of the semiconductor switch 2 can be appropriately performed regardless of the load 52.

[0068] Furthermore, in the control device 3 of this embodiment, the cutoff operation execution unit 32c controls the gate electrode 21g of the semiconductor switch 2 to perform a cutoff operation for each of the N cutoff operation regions based on predetermined gate voltage change information. This allows the control device 3 of this embodiment to reliably perform an appropriate cutoff operation of the semiconductor switch 2 in accordance with the detected current.

[0069] In the control device 3 of this embodiment, the gate voltage change information includes a plurality of sets of change information each consisting of a voltage applied to the gate electrode 21g and an application time thereof. As a result, the control device 3 of this embodiment can operate the gate electrode 21g and thus the semiconductor switch 2 in a stepwise manner, and can reliably cause the semiconductor switch 2 to perform an appropriate cut-off operation.

[0070] Here, the effect of the control device 3 of this embodiment will be specifically described with reference to Figs. 8 and 9. Fig. 8 is a waveform diagram for explaining an operation example of the control device 3. Fig. 9 is a waveform diagram for explaining another operation example of the control device 3. In the following explanation, the operation example of Fig. 8 will be described by exemplifying, for example, a case where a steep current such as an inrush current flows through the semiconductor switch 2 to the load 52. Also, the operation example of Fig. 9 will be described by exemplifying, for example, a case where the wiring inductance of the load 52 is large and the increase in the current to the load 52 is relatively gradual.

[0071] 8, in an example of the cutoff operation of the semiconductor switch 2, as indicated by 801 in FIG. 8, an applied voltage VGS_(11) is applied to the gate electrode 21g during a period ts_(11) from time 0 to time T21, as indicated by a solid line 80. In addition, an applied voltage VGS_(12) is applied to the gate electrode 21g during a period ts_(12) from time T21 to time T22. In addition, an applied voltage VGS_(13) is applied to the gate electrode 21g during a period ts_(13) from time T22 to time T23.

[0072] Furthermore, during a period ts_(14) from time T23 to time T24, the applied voltage VGS_(14) is applied to the gate electrode 21g. Then, at time T24, the cutoff operation execution unit 32c in the control device 3 determines that the passing current through the semiconductor switch 2 has become zero, and applies the gate hold voltage VGS_min to the gate electrode 21g. As a result, the control device 3 opens the semiconductor switch 2 and ends the cutoff operation.

[0073] Furthermore, when the applied voltages VGS_(11), VGS_(12), VGS_(13), and VGS_(14) are applied to the gate electrode 21g during the four periods ts_(11), ts_(12), ts_(13), and ts_(14), respectively, as described above, the detection current detected by the current sensor 4, i.e., the passing current of the semiconductor switch 2, changes as shown by the solid line 90 of 802 in Fig. 8. As a result, it was confirmed that in this example of the cutoff operation, the control device 3 repeatedly performs the cutoff operation four times, thereby bringing the semiconductor switch 2 into an open state.

[0074] 9, in an example of the cutoff operation of the semiconductor switch 2, as shown in 901, an applied voltage VGS_(N1) is applied to the gate electrode 21g during a period ts_(N1) from time 0 to time T31, as indicated by a solid line 81. In addition, an applied voltage VGS_(N2) is applied to the gate electrode 21g during a period ts_(N2) from time T31 to time T32. In addition, an applied voltage VGS_(N3) is applied to the gate electrode 21g during a period ts_(N3) from time T32 to time T33.

[0075] Furthermore, during a period ts_(N4) from time T33 to time T34, the applied voltage VGS_(N4) is applied to the gate electrode 21g. Furthermore, during a period ts_(N5) from time T34, the applied voltage VGS_(N5) is applied to the gate electrode 21g, and then a cutoff operation is performed using an applied voltage smaller than the applied voltage VGS_(N5). Thereafter, in the control device 3, the cutoff operation execution unit 32c determines that the passing current passing through the semiconductor switch 2 has become zero, and applies the gate holding voltage VGS_min to the gate electrode 21g. As a result, the control device 3 places the semiconductor switch 2 in an open state and ends the cutoff operation.

[0076] Furthermore, when the applied voltages VGS_(N1), VGS_(N2), VGS_(N3), VGS_(N4), and VGS_(N5) are applied to the gate electrode 21g during the five periods ts_(N1), ts_(N2), ts_(N3), ts_(N4), and ts_(N5) as described above, the detection current detected by the current sensor 4, i.e., the passing current of the semiconductor switch 2, changes as shown by the solid line 91 of 902 in Fig. 9. As a result, in this example of the cutoff operation, it was confirmed that the semiconductor switch 2 can be opened by the control device 3 repeatedly performing the cutoff operation five or more times.

[0077] As shown by solid line 90 of 802 in FIG. 8 and solid line 91 of 902 in FIG. 9, it was confirmed that the slope of the passing current during the cut-off operation can be changed depending on the operation content of the cut-off operation in the semiconductor switch 2, i.e., the voltage applied to the gate electrode 21g and / or the application time. In other words, it was demonstrated that the control device 3 of this embodiment can change the slope of the passing current during the cut-off operation depending on the slope of the detected current when an overcurrent is detected, and the cut-off operation of the semiconductor switch 2 can be appropriately performed regardless of the load 52 connected to the semiconductor switch 2.

[0078] In the above description, the overcurrent threshold, the N shutoff operating regions, and the gate voltage change information in each shutoff operating region are set and stored in advance in the storage unit 34. However, the present disclosure is not limited to this, and the overcurrent threshold, the N shutoff operating regions, and the gate voltage change information in each shutoff operating region may be appropriately set from an external device such as a server via a communication interface or the like provided in the semiconductor shutoff system 1.

[0079] [Software implementation example] The function of the control device 3 (hereinafter referred to as the "device") is a program for causing a computer to function as the device, and can be realized by a control program for causing a computer to function as the control block of the device (in particular, the detected current slope acquisition unit 31 and the opening / closing control unit 32).

[0080] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the control program. The control device and storage device execute the control program to realize each function described in the above embodiment.

[0081] The control program may be non-transitory and may be recorded in one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0082] In addition, some or all of the functions of each of the control blocks can be realized by a logic circuit. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of each of the control blocks can be realized by, for example, a quantum computer.

[0083] The recording medium may be a "non-transitory tangible medium" such as a ROM (Read Only Memory) or a tape, disk, card, semiconductor memory, programmable logic circuit, or the like. The computer may further include a RAM (Random Access Memory) into which the program is expanded. The program may be supplied to the computer via any transmission medium capable of transmitting the program (such as a communication network or broadcast waves). One aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0084] Furthermore, each process described in the above embodiment may be executed by AI (Artificial Intelligence). In this case, the AI ​​may be operated by the control device or another device (for example, an edge computer or a cloud server).

[0085] 〔summary〕 In order to solve the above problems, a control device according to a first aspect of the present disclosure is a semiconductor system including a semiconductor switch having one end connected to a power source and the other end connected to a load, and configured to cut off a current from the power source to the load, and a current sensor configured to detect a current flowing from the power source to the semiconductor switch. The control device controls the semiconductor switch, and includes a detected current slope acquisition unit that determines a change over time in the detected current detected by the current sensor and acquires the determined change over time in the detected current as a slope of the detected current, and an opening / closing control unit that uses a result acquired by the detected current slope acquisition unit to control the opening and closing of the semiconductor switch.

[0086] According to the above configuration, the switching control unit turns the semiconductor switch on or off based on the slope of the detected current acquired by the detected current slope acquisition unit. In this way, the switching control unit causes the semiconductor switch to perform an interruption operation in consideration of the detected current passing through the semiconductor switch and flowing toward the load, so that it is possible to suppress the occurrence of a surge voltage regardless of the load connected to the semiconductor switch.

[0087] In addition, in the control device according to aspect 2 of the present disclosure, in aspect 1, the opening / closing control unit may be provided with an interruption determination processing unit that determines whether or not an interruption operation of the semiconductor switch is required by comparing the detected current detected by the current sensor with a predetermined overcurrent threshold.

[0088] According to the above configuration, the switching control unit can appropriately determine whether or not the semiconductor switch needs to be turned off by the interruption determination processing unit, thereby enabling the switching control unit to appropriately control the opening and closing of the semiconductor switch.

[0089] In addition, in the control device according to aspect 2 of the present disclosure, in aspect 1 or aspect 2, the opening / closing control unit may include a shutoff operation selection unit that selects one of N predetermined shutoff operation areas (N is an integer equal to or greater than 2) based on the acquired result, and a shutoff operation execution unit that causes the semiconductor switch to execute a shutoff operation corresponding to the shutoff operation area selected by the shutoff operation selection unit.

[0090] According to the above configuration, the shutoff operation selection unit selects one shutoff operation region based on the obtained result. The shutoff operation execution unit causes the semiconductor switch to execute a shutoff operation corresponding to the selected shutoff operation region. This allows the opening / closing control unit to more appropriately perform the shutoff operation of the semiconductor switch, and can further suppress the occurrence of surge voltage regardless of the load connected to the semiconductor switch.

[0091] In addition, in the control device according to aspect 4 of the present disclosure, in aspect 3, an upper limit value of the N values ​​may be determined based on the magnitude of a breaking current in the semiconductor switch.

[0092] According to the above configuration, it is possible to appropriately determine N ranges, where N is an integer equal to or greater than 2, based on the magnitude of the breaking current in the semiconductor switch. This makes it possible to reliably determine an appropriate breaking operation region according to the characteristics of the semiconductor switch, and to allow the semiconductor switch to perform a breaking operation appropriately regardless of the load.

[0093] In addition, in the control device according to aspect 5 of the present disclosure, in aspect 3 or aspect 4, the cut-off operation execution unit may control the gate electrode of the semiconductor switch to perform a cut-off operation based on predetermined gate voltage change information for each of the N cut-off operation regions.

[0094] According to the above configuration, the cutoff operation execution unit controls the gate electrode of the semiconductor switch based on the gate voltage change information for each cutoff operation region, thereby causing the semiconductor switch to perform the cutoff operation. This makes it possible to reliably cause the semiconductor switch to perform an appropriate cutoff operation in response to the detected current.

[0095] In addition, in the control device according to aspect 6 of the present disclosure, in addition to aspect 5, the gate voltage change information may include a plurality of sets of change information each including a voltage applied to the gate electrode and an application time thereof.

[0096] According to the above-mentioned configuration, the gate electrode and therefore the semiconductor switch can be operated in a stepwise manner, and an appropriate cutoff operation can be reliably performed in the semiconductor switch.

[0097] In addition, in the control device according to aspect 7 of the present disclosure, in any one of aspects 3 to 6, the cutting operation execution unit may terminate the cutting operation of the semiconductor switch when it determines that the detected current has become zero.

[0098] According to the above configuration, the interruption operation of the semiconductor switch can be appropriately terminated, so that the semiconductor switch can be controlled with high precision.

[0099] In addition, a semiconductor interruption system according to aspect 8 of the present disclosure includes a semiconductor switch having one end connected to a power source and the other end connected to a load, which interrupts a current from the power source to the load, a current sensor which detects a current flowing from the power source to the semiconductor switch, and a control device according to any one of aspects 1 to 7.

[0100] In addition, in the semiconductor shutoff system according to aspect 9 of the present disclosure, in aspect 8, a bipolar transistor, a MOSFET, or an IGBT may be used for the semiconductor switch.

[0101] Furthermore, a method for controlling a semiconductor switch according to aspect 10 of the present disclosure is a method for controlling a semiconductor switch in a semiconductor system including a semiconductor switch having one end connected to a power source and the other end connected to a load, and configured to cut off a current from the power source to the load, and a current sensor for detecting a current flowing from the power source to the semiconductor switch, the method including a detected current slope acquisition step of determining a change over time in the detected current detected by the current sensor and acquiring the determined change over time in the detected current as a slope of the detected current, and an opening / closing control step of controlling the opening and closing of the semiconductor switch using a result acquired in the detected current slope acquisition step.

[0102] In addition, a control program according to aspect 11 of the present disclosure is a control program for causing a computer to function as a control device of any one of aspects 1 to 5, and causes a computer to function as the detected current slope acquisition unit and the opening / closing control unit.

[0103] A recording medium according to a twelfth aspect of the present disclosure is a computer-readable recording medium having the control program of the ninth aspect recorded thereon.

[0104] According to the configurations of the eighth to twelfth aspects, the same effects as those of the first aspect can be achieved.

[0105] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0106] 1. Semiconductor Interrupter System 2. Semiconductor Switch 21g Gate electrode 3. Control device 31 Detected current gradient acquisition unit 32 Opening and closing control section 32a Blocking judgment processing unit 32b Cut-off operation selection unit 32c Cut-off operation execution unit 4 Current Sensor 51 Power supply 52 Load

Claims

1. a semiconductor switch having one end connected to a power source and the other end connected to a load, the semiconductor switch cutting off a current from the power source to the load; a current sensor that detects a current flowing from the power supply to the semiconductor switch, a detected current gradient acquisition unit that acquires a temporal change in the detected current detected by the current sensor and acquires the acquired temporal change in the detected current as a gradient of the detected current; a switching control unit that uses an acquisition result from the detected current gradient acquisition unit to perform opening and closing control of the semiconductor switch.

2. The opening / closing control unit is 2. The control device according to claim 1, further comprising: an interruption determination processing unit that determines whether or not an interruption operation of the semiconductor switch is required by comparing a detection current detected by the current sensor with a predetermined overcurrent threshold.

3. The opening / closing control unit is a cutoff operation selection unit that selects one of N predetermined cutoff operation regions (N is an integer equal to or greater than 2) based on the acquired result; The control device according to claim 1 , further comprising: a cutoff operation execution unit that causes the semiconductor switch to execute a cutoff operation in accordance with the cutoff operation region selected by the cutoff operation selection unit.

4. 4. The control device according to claim 3, wherein an upper limit of the N number of values ​​is determined based on the magnitude of a breaking current in the semiconductor switch.

5. 4. The control device according to claim 3, wherein the cutoff operation execution unit controls a gate electrode of the semiconductor switch to perform a cutoff operation for each of the N cutoff operation regions based on predetermined gate voltage change information.

6. 6. The control device according to claim 5, wherein the gate voltage change information includes a plurality of sets of change information each consisting of a voltage applied to the gate electrode and an application time thereof.

7. The control device according to claim 3 , wherein the interruption operation execution unit terminates the interruption operation of the semiconductor switch when it determines that the detected current has become zero.

8. a semiconductor switch having one end connected to a power source and the other end connected to a load, the semiconductor switch cutting off a current from the power source to the load; a current sensor for detecting a current flowing from the power supply to the semiconductor switch; A semiconductor shutdown system comprising: a control device according to any one of claims 1 to 7.

9. 9. The semiconductor shutoff system of claim 8, wherein the semiconductor switch is a bipolar transistor, a MOSFET, or an IGBT.

10. A control method for controlling a semiconductor switch in a semiconductor system including a semiconductor switch having one end connected to a power source and the other end connected to a load, the semiconductor switch interrupting a current flowing from the power source to the load, and a current sensor detecting a current flowing from the power source to the semiconductor switch, the method comprising: a detected current gradient acquisition step of determining a temporal change in a detected current detected by the current sensor and acquiring the determined temporal change in the detected current as a gradient of the detected current; an opening and closing control step of controlling the opening and closing of the semiconductor switch by using a result acquired in the detected current gradient acquisition step.

11. A control program for causing a computer to function as the control device according to claim 1 , the control program causing a computer to function as the detected current gradient acquisition section and the switching control section.

12. A computer-readable recording medium having the control program according to claim 11 recorded thereon.

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