Solar control device, method, program, and vehicle

Abstract

To provide a solar controller and the like, capable of determining whether there is a short-circuit fault or an open-circuit fault in each of arms of a DC-DC converter while avoiding erroneous determination due to a decrease in the amount of solar radiation.SOLUTION: Provided is a solar controller configured to control a solar unit including: a solar panel; a step-up and step-down DC-DC converter configured to receive, as an input, electric power generated by the solar panel, convert the received electric power to predetermined electric power, and output the predetermined electric power; and a regulator circuit inserted between an output of the DC-DC converter and a ground potential. The solar controller includes; a voltage acquisition part that acquires input and output voltages of the DC-DC converter; a current acquisition part that acquires input and output currents of the DC-DC converter; and a control part that controls the regulator circuit and switching elements that respectively make up arms included in the DC-DC converter and determines whether an abnormality in each of the arms in the DC-DC converter has occurred based on values acquired by the voltage acquisition part and the current acquisition part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a solar control device that controls a solar charging system that charges a battery using power generated by a solar panel. [Background technology]

[0002] Patent Document 1 discloses a device that detects the occurrence of a short-circuit fault in elements (switching elements and rectifier elements) that constitute each arm of a DCDC converter that receives power generated by a solar panel as input. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-093559 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the judgment method using the device described in the above Patent Document 1, the presence or absence of an abnormality is judged even when the amount of solar radiation decreases and the power generated by the solar panel is low, so there is a risk of erroneously judging a short-circuit fault in the elements that make up each arm of the DCDC converter.

[0005] In addition, the determination method using the device described in Patent Document 1 above is capable of determining an abnormality caused by a short-circuit failure of elements that configure each arm of the DC-DC converter, but is unable to determine an abnormality caused by an open-circuit failure of these elements.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a solar control device and the like that can determine abnormalities such as short-circuit and open-circuit faults in each arm of a DCDC converter while avoiding erroneous judgments caused by a decrease in solar radiation. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the disclosed technology is a solar control device that controls a solar unit that includes a solar panel, a step-up / step-down type DCDC converter that inputs power generated by the solar panel and converts it to a predetermined power and outputs it, and an adjustment circuit that is inserted between the output of the DCDC converter and ground potential, and the solar control device includes a voltage acquisition unit that acquires the input voltage and output voltage of the DCDC converter, a current acquisition unit that acquires the input current and output current of the DCDC converter, and a control unit that controls the switching elements and adjustment circuits that constitute each arm of the DCDC converter and determines an abnormality in each arm of the DCDC converter based on the value of the voltage acquisition unit or the current acquisition unit. Effect of the Invention

[0008] According to the solar control device disclosed herein, it is possible to appropriately determine abnormalities such as short circuit failures and open circuit failures in each arm of the DCDC converter while avoiding erroneous determinations caused by a decrease in the amount of solar radiation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a solar unit including a solar control device according to an embodiment of the present disclosure. [Diagram 2] A flowchart explaining a first abnormality determination process executed by a solar control device. [Diagram 3] The state of each switching element of the solar DDC and the adjustment circuit in the first abnormality determination process [Figure 4] A diagram showing the current in a normal solar unit during the first abnormality determination process. [Diagram 5] A diagram showing the current in an abnormal solar unit during the first abnormality determination process. [Figure 6] A flowchart explaining a second abnormality determination process executed by the solar control device. [Figure 7]The state of each switching element of the solar DDC and the adjustment circuit in the second abnormality determination process [Figure 8] A diagram showing the current in a normal solar unit during the second abnormality determination process [Figure 9A] A diagram showing the current in an abnormal solar unit during the second abnormality determination process. [Figure 9B] FIG. 11 is a diagram showing another current in an abnormal solar unit during the second abnormality determination process. [Figure 10] A flowchart explaining a third abnormality determination process executed by a solar control device. [Figure 11] The state of each switching element of the solar DDC and the adjustment circuit in the third abnormality determination process [Figure 12] A diagram showing the current in a normal solar unit during the third abnormality determination process [Figure 13A] A diagram showing the current in an abnormal solar unit during the third abnormality determination process. [Figure 13B] A diagram showing other currents in an abnormal solar unit during the third abnormality determination process. [Figure 14] A flowchart explaining a fourth abnormality determination process executed by the solar control device. [Figure 15] The state of each switching element of the solar DDC and the adjustment circuit in the fourth abnormality determination process [Figure 16] A diagram showing the current in a normal solar unit during the fourth abnormality determination process [Figure 17] A diagram showing the current in an abnormal solar unit during the fourth abnormality determination process. [Figure 18] FIG. 1 is a diagram showing a schematic configuration of a solar unit including a solar DDC according to a first modified example. [Figure 19] States of the switching elements of the solar DDC and the adjustment circuit in the first to fourth abnormality determination processes of the first modification [Figure 20] FIG. 13 is a diagram showing a schematic configuration of a solar unit including a solar DDC according to a second modified example. [Figure 21]States of the switching elements of the solar DDC and the adjustment circuit in the first to fourth abnormality determination processes of the second modification [Figure 22] A diagram showing the schematic configuration of a solar unit as an application example. [Figure 23] The state of each switching element of the solar DDC and the adjustment circuit of the solar unit of the application example in the first to fourth abnormality determination processes DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The solar control device according to the present disclosure determines short-circuit and open-circuit faults in the buck upper arm, buck lower arm, boost upper arm, and boost lower arm that make up the DCDC converter using the input / output voltage and input / output current values ​​of the DCDC converter and a large-capacity capacitor connected to the output side of the DCDC converter. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] <Embodiment> [composition] FIG. 1 is a block diagram showing a schematic configuration of a solar unit including a solar control device according to an embodiment of the present disclosure. The solar unit 1 illustrated in FIG. 1 includes a solar panel 10, an output circuit 20, a solar DDC 30, an adjustment circuit 40, a solar control device 50 according to the present embodiment, an input voltage detection unit Vin, an input current detection unit Iin, an output voltage detection unit Vout, an output current detection unit Iout, and a capacitor C. In FIG. 1, a connection line for transmitting and receiving power is indicated by a solid line, and a connection line for communicating control instructions, detection values, and the like is indicated by a dotted line. This solar unit 1 can be mounted on a vehicle or the like.

[0012] The solar panel 10 is a power generating device that generates power by receiving irradiation of sunlight, and is typically a solar cell module that is an assembly of solar cells. The solar panel 10 can be installed, for example, on the roof of a vehicle. The solar panel 10 is connected to a solar DDC 30, which will be described later, and the power generated by the solar panel 10 is output to the solar DDC 30.

[0013] The input voltage detection unit Vin is configured, for example, by a voltage sensor, and is provided to detect the voltage output from the solar panel 10 to the solar DDC 30 in accordance with the generated power, i.e., the voltage input to the solar DDC 30. The input voltage of the solar DDC 30 detected by the input voltage detection unit Vin is output to the solar control device 50.

[0014] The input current detection unit Iin is configured, for example, by a current sensor, and is provided to detect the current output from the solar panel 10 to the solar DDC 30 in accordance with the generated power, i.e., the current input to the solar DDC 30. The input current of the solar DDC 30 detected by the input current detection unit Iin is output to the solar control device 50.

[0015] The output circuit 20 is configured to receive the supply of electric power output from the solar DDC 30. Examples of this output circuit 20 include a high-voltage DCDC converter that supplies electric power to a high-voltage battery (not shown) that is a secondary battery such as a lithium-ion battery, and an auxiliary DCDC converter that supplies electric power to an auxiliary battery (not shown) that is a secondary battery such as a lead battery, and an auxiliary system.

[0016] The output voltage detection unit Vout is configured, for example, by a voltage sensor, and is provided to detect the voltage output from the solar DDC 30 to the output circuit 20. The voltage detected by this output voltage detection unit Vout is the voltage at the connection point (hereinafter referred to as the "middle point") that connects the output side of the solar DDC 30 and the input side of the output circuit 20 (such as the high-voltage DCDC converter and the auxiliary DCDC converter). The output voltage of the solar DDC 30 detected by the output voltage detection unit Vout is output to the solar control device 50.

[0017] The output current detection unit Iout is configured, for example, by a current sensor, and is provided to detect the current output from the solar DDC 30 to the output circuit 20. The output current of the solar DDC 30 detected by the output current detection unit Iout is output to the solar control device 50.

[0018] The capacitor C is connected to the midpoint between the solar DDC 30 and the output circuit 20 (such as the high-voltage DCDC converter and the auxiliary DCDC converter). This capacitor C is a large-capacitance storage element that is used to charge and discharge the power generated by the solar panel 10 and output from the solar DDC 30 as needed, and to stabilize the voltage at the midpoint.

[0019] The solar DDC 30 is a step-up / step-down type DCDC converter that supplies power generated by the solar panel 10 to the output circuit 20. When supplying power, the solar DDC 30 can convert (step-up / step-down) the generated voltage of the solar panel 10, which is the input voltage, to a predetermined voltage and output it to the output circuit 20. This solar DDC 30 includes in its configuration a switching element M1 which is an element of the step-down upper arm, a switching element M2 which is an element of the step-down lower arm, an inductor L, a switching element M3 which is an element of the step-up lower arm, and a rectifier element D4 which is an element of the step-up upper arm.

[0020] The switching elements M1, M2, and M3 are active elements that can be controlled to switch ON / OFF by the solar control device 50, and are, for example, transistors. These switching elements M1, M2, and M3 can pass current when they are controlled to be ON (ON voltage is applied to the gate). For example, a metal oxide semiconductor field effect transistor (MOSFET) can be used as the transistor. The rectifier element D4 is an active element that can pass current in one direction, and is, for example, a diode. For example, a Schottky barrier diode can be used as the diode. The inductor L is a passive element that can generate a magnetic field by the current that flows and store magnetic energy. This inductor L has a constant current characteristic that tries to maintain the current. For example, a choke coil can be used as the inductor L.

[0021] The source of the switching element M1 is connected to the solar panel 10 (positive output terminal). The drain of the switching element M1 is connected to the source of the switching element M2. The drain of the switching element M2 is grounded (ground potential). The cathode of the rectifier element D4 is connected to the output circuit 20 and the adjustment circuit 40. The anode of the rectifier element D4 is connected to the source of the switching element M3. The cathode of the rectifier element D4 is connected to the output circuit 20. The drain of the switching element M3 is grounded. The gates of the switching elements M1, M2, and M3 are each connected to the solar control device 50. The inductor L is inserted between the connection point between the drain of the switching element M1 and the source of the switching element M2 and the connection point between the anode of the rectifier element D4 and the source of the switching element M3.

[0022] The solar DDC 30 forms a step-down circuit using the switching element M1, the switching element M2, and the inductor L, and can step down the output voltage from the solar panel 10 and output it to the output circuit 20. The solar DDC 30 also forms a step-up circuit using the inductor L, the switching element M3, and the rectifier element D4, and can step up the output voltage from the solar panel 10 and output it to the output circuit 20. This solar DDC 30 configures a solar unit including the above-mentioned solar panel 10 and an adjustment circuit 40 described later. Note that the adjustment circuit 40 may be provided outside the solar unit.

[0023] The adjustment circuit 40 is a circuit that adjusts the voltage at the midpoint where the solar DDC 30 and the output circuit 20 are connected, and is inserted between the output side of the solar DDC 30 and the ground potential. The adjustment circuit 40 includes a resistor R1, a resistor R2, a switching element M5, and a switching element M6.

[0024] The switching elements M5 and M6 are active elements that can be controlled to switch ON / OFF by the solar control device 50, and are, for example, transistors. The switching elements M5 and M6 can pass current when controlled to be ON. For the transistors, for example, MOSFETs can be used. The resistor R1 is inserted between the source of the switching element M5, whose drain is connected to the source of the switching element M6, whose drain is grounded, and the midpoint, and a short-circuit path of the midpoint via the resistor R1 is formed by controlling the switching elements M5 and M6 to be ON. The resistor R2 is inserted between the source of the switching element M6, whose drain is grounded, and the midpoint, and a discharge path of the midpoint voltage via the resistor R2 is formed by controlling the switching element M5 to be OFF (applying an OFF voltage to the gate) and controlling the switching element M6 to be ON. Therefore, the resistor R1 that performs the short circuit is set smaller than the resistor R2 that performs the discharge. As an example, the resistor R1 can be set to 0.05Ω and the resistor R2 to be 100Ω.

[0025] The solar control device 50 includes at least an acquisition unit 51 and a control unit 52. The acquisition unit 51 acquires the voltage and current values ​​detected by the input voltage detection unit Vin, the input current detection unit Iin, the output voltage detection unit Vout, and the output current detection unit Iout, respectively. The control unit 52 controls the gate voltages of the switching elements M1, M2, and M3 of the solar DDC 30 and the switching elements M5 and M6 of the adjustment circuit 40 to control the ON / OFF switching of each switching element. Note that some or all of the input voltage detection unit Vin, the input current detection unit Iin, the output voltage detection unit Vout, and the output current detection unit Iout may be configured in the solar control device 50.

[0026] The solar control device 50 according to this embodiment appropriately controls the ON / OFF state of each switching element, and performs a process of determining an abnormality in each arm (element constituting each arm) of the solar DDC 30 based on the values ​​of the input / output voltage and input / output current of the solar DDC 30 obtained from the result of the control. Details of the abnormality determination process performed by the solar control device 50 will be described later.

[0027] A part or the whole of this solar control device 50 can be configured as an electronic control unit (ECU) that typically includes a processor, a memory, an input / output interface, etc. This electronic control device can perform various controls by having the processor read and execute programs stored in the memory.

[0028] [Abnormality Judgment Control] Next, the abnormality determination control executed by the solar control device 50 will be described with further reference to Fig. 2 to Fig. 17. The solar control device 50 according to this embodiment performs each process of "first abnormality determination" for determining a short-circuit fault in the step-down upper arm, "second abnormality determination" for determining an open circuit fault in the step-down upper arm and the step-up upper arm, "third abnormality determination" for determining a short-circuit fault in the step-down lower arm and the step-up lower arm, and "fourth abnormality determination" for determining a short-circuit fault in the step-up upper arm. These abnormality determination processes are typically performed before the solar charging system including the solar unit 1 and a battery (not shown) is operated and power generation / charging control is started (the solar DDC 30 is started).

[0029] (1) First abnormality judgment process Fig. 2 is a flow chart explaining the first abnormality judgment process executed by the solar control device 50. Fig. 3 is a diagram showing the state of each switching element of the solar DDC 30 and the adjustment circuit 40 controlled in the first abnormality judgment process. Fig. 4 is a diagram showing the current flow when the switching element M1 is normal in the solar unit 1 during the first abnormality judgment process. Fig. 5 is a diagram showing the current flow when the switching element M1 is abnormal in the solar unit 1 during the first abnormality judgment process.

[0030] (Step S201) The solar control device 50 performs discharge to reduce the midpoint voltage (output voltage of the solar DDC 30). In this midpoint voltage discharge process, as shown in Fig. 3, the switching element M1 of the step-down upper arm, the switching element M2 of the step-down lower arm, and the switching element M3 of the step-up lower arm of the solar DDC 30 are each controlled to be OFF, and the switching element M5 of the adjustment circuit 40 is controlled to be OFF and the switching element M6 to be ON to form a discharge path. By controlling each switching element in this way, a current discharge path indicated by the dashed arrow in Fig. 4 is formed. Once the midpoint voltage discharge process has been performed, the process proceeds to step S202.

[0031] (Step S202) The solar control device 50 judges whether or not a first time has elapsed since the midpoint voltage discharge process was performed. This judgment is performed to reliably reduce the midpoint voltage (output voltage of the solar DDC 30) when the step-down upper arm and the step-up upper arm are not open-circuit faulted. Therefore, the first time can be set to the time required to reduce the maximum midpoint voltage that the solar DDC 30 can have in the solar unit 1 to a predetermined first voltage V1 (typically zero). If the first time has elapsed (step S202, Yes), the process proceeds to step S203. On the other hand, if the first time has not elapsed (step S202, No), the process proceeds to step S201.

[0032] (Step S203) The solar control device 50 judges whether the input voltage of the solar DDC 30 is equal to or greater than the first threshold Vth1. This judgment is made to confirm whether the solar panel 10 generates enough power (whether there is a certain amount of solar radiation or more) to perform the abnormality judgment with high accuracy. Therefore, the first threshold Vth1 can be appropriately set based on the voltage required for the first abnormality judgment process. If the input voltage of the solar DDC 30 is equal to or greater than the first threshold Vth1 (step S203, Yes), the process proceeds to step S204. On the other hand, if the input voltage of the solar DDC 30 is less than the first threshold Vth1 (step S203, No), the first abnormality judgment process ends.

[0033] (Step S204) The solar control device 50 judges whether or not there is a short circuit fault in the step-down upper arm (switching element M1) of the solar DDC 30. As shown in Fig. 3, like the midpoint voltage discharge process, this step-down upper arm short circuit fault judgment process is performed as follows in a state in which the switching element M1 of the step-down upper arm, the switching element M2 of the step-down lower arm, and the switching element M3 of the step-up lower arm of the solar DDC 30 are each controlled to be OFF, and the switching element M5 of the adjustment circuit 40 is controlled to be OFF and the switching element M6 to be ON to form a discharge path for the midpoint voltage.

[0034] If the switching element M1 of the step-down upper arm is normal, no current flows between the source and drain, so even if the solar panel 10 generates power by OFF control, no current flows to the solar DDC 30. Therefore, after the first hour of continuous discharge, the midpoint voltage detected by the output voltage detection unit Vout becomes almost equal to zero. On the other hand, if an abnormality occurs in the switching element M1 of the step-down upper arm such that the source and drain are short-circuited, a current continues to flow from the solar panel 10 to the solar DDC 30 as shown in FIG. 5. Therefore, even if the first hour of continuous discharge is continued, the midpoint voltage does not become zero, and becomes almost equal to the input voltage of the solar DDC. Therefore, the solar control device 50 judges whether or not there is a short-circuit fault in the step-down upper arm based on the following judgment condition 1-1 or 1-2.

[0035] Judgment condition 1-1 If the absolute value of the difference between the input voltage (detection value of the input voltage detector Vin) and the midpoint voltage (detection value of the output voltage detector Vout) of the solar DDC 30 is less than the second threshold value Vth2 (Equation 1), it is determined that the step-down upper arm has a short-circuit fault. The second threshold value Vth2 is set to a predetermined value obtained by adding a determination margin to zero. |Solar DDC input voltage - midpoint voltage|< second threshold Vth2 ... (Equation 1)

[0036] Judgment criteria 1-2 If the midpoint voltage (the detection value of the output voltage detection unit Vout) exceeds the third threshold Vth3 (Equation 2), it is determined that the step-down upper arm has a short-circuit fault. The third threshold Vth3 is set to a value that is greater than the first voltage V1 at which the midpoint voltage drops due to the discharge process, and smaller than the first threshold Vth1 that determines whether the solar panel 10 is generating sufficient power. Midpoint voltage>third threshold Vth3 ... (Equation 2)

[0037] According to this first abnormality determination process, it is possible to determine a short circuit fault occurring in the step-down upper arm of the solar DDC 30 before the solar charging system operates and power generation / charging control is started. This makes it possible to avoid a situation in which the midpoint voltage (output voltage of the solar DDC 30) rises too much (midpoint overvoltage) and the capacitor C breaks down. In addition, when the solar panel 10 cannot generate sufficient power, the first abnormality determination process is not started or is stopped even after it has started, so that it is possible to prevent erroneous determination of a short circuit fault in the step-down upper arm.

[0038] (2) Second abnormality judgment process Fig. 6 is a flow chart explaining the second abnormality determination process executed by the solar control device 50. Fig. 7 is a diagram showing the state of each switching element of the solar DDC 30 and the adjustment circuit 40 controlled in the second abnormality determination process. Fig. 8 is a diagram showing the current flow when the switching element M1 and the rectifier element D4 are both normal in the solar unit 1 during the second abnormality determination process. Figs. 9A and 9B are diagrams showing the current flow when the switching element M1 or the rectifier element D4 is abnormal in the solar unit 1 during the second abnormality determination process.

[0039] (Step S601) The solar control device 50 performs a solar panel voltage judgment to confirm whether the solar panel 10 generates enough power (whether there is a certain amount of solar radiation or more) to perform an abnormality judgment with high accuracy. In this solar panel voltage judgment process, as shown in FIG. 7, the switching element M1 of the step-down upper arm, the switching element M2 of the step-down lower arm, and the switching element M3 of the step-up lower arm of the solar DDC 30 are each controlled to be OFF, and the switching element M5 and the switching element M6 of the adjustment circuit 40 are each controlled to be ON to form a short circuit path. By controlling these switching elements, the solar DDC 30 becomes inoperative, and the output voltage of the solar panel 10, that is, the input voltage of the solar DDC 30, can be detected and obtained. After the solar panel voltage judgment process is performed, the process proceeds to step S602.

[0040] (Step S602) When the input voltage of the solar DDC 30 becomes detectable and obtainable, the solar control device 50 judges whether the input voltage of the solar DDC 30 is equal to or higher than the fourth threshold Vth4. This judgment is made to confirm whether the solar panel 10 generates enough power (whether there is a certain amount of solar radiation or more) to perform the abnormality judgment with high accuracy. Therefore, the fourth threshold Vth4 can be appropriately set based on the voltage required for the second abnormality judgment process. Note that the fourth threshold Vth4 may be the same as or different from the first threshold Vth1 described above. If the input voltage of the solar DDC 30 is equal to or higher than the fourth threshold Vth4 (step S602, Yes), the process proceeds to step S603. On the other hand, if the input voltage of the solar DDC 30 is less than the fourth threshold Vth4 (step S602, No), the second abnormality judgment process ends.

[0041] (Step S603) The solar control device 50 judges the presence or absence of an open circuit fault in the buck upper arm (switching element M1) and the boost upper arm (rectifier element D4) of the solar DDC 30. This buck upper / boost upper arm open circuit fault judgment process is performed as follows, in a state in which the switching element M1 of the buck upper arm of the solar DDC 30 is controlled to ON, the switching element M2 of the buck lower arm and the switching element M3 of the boost lower arm are controlled to OFF, and the switching elements M5 and M6 of the adjustment circuit 40 are controlled to ON to form a short circuit path in the solar panel 10.

[0042] If both the switching element M1 of the step-down upper arm and the rectifier element D4 of the step-up upper arm are normal, a short-circuit current flows from the solar panel 10 as shown in FIG. 8, and the input voltage of the solar DDC 30 becomes almost equal to zero based on the IV characteristics of the solar panel 10. On the other hand, if an open circuit occurs in the switching element M1 of the step-down upper arm, no current flows between the source and drain as shown in FIG. 9A, and the input voltage of the solar DDC 30 becomes the open circuit voltage (maximum value) based on the IV characteristics of the solar panel 10. Even if an open circuit occurs in the rectifier element D4 of the step-up upper arm, no current flows to the output side of the solar DDC 30 as shown in FIG. 9B, and the input voltage of the solar DDC 30 becomes the open circuit voltage based on the IV characteristics of the solar panel 10. Therefore, the solar control device 50 judges the presence or absence of an open circuit fault in the step-down upper arm and the step-up upper arm based on the following judgment condition 2.

[0043] Criterion 2 If the input voltage of the solar DDC 30 (the detection value of the input voltage detection unit Vin) exceeds the fifth threshold Vth5 (Equation 3), it is determined that at least one of the step-down upper arm and the step-up upper arm has an open circuit fault. The fifth threshold Vth5 is set to a predetermined value that is greater than zero and less than the fourth threshold Vth4. Solar DDC input voltage > 5th threshold Vth5 … (Equation 3)

[0044] According to this second abnormality determination process, it is possible to determine an open circuit fault occurring in the step-down upper arm or the step-up upper arm of the solar DDC 30 before the solar charging system is activated and power generation / charging control is started. This makes it possible to grasp a situation in which charging control cannot be performed using the power generated by the solar panel 10. Furthermore, when the solar panel 10 cannot generate sufficient power, the second abnormality determination process is not started, which prevents erroneous determination of an open circuit fault in the step-down upper arm or the step-up upper arm.

[0045] (3) Third abnormality judgment process Fig. 10 is a flow chart explaining the third abnormality determination process executed by the solar control device 50. Fig. 11 is a diagram showing the state of each switching element of the solar DDC 30 and the adjustment circuit 40 controlled in the third abnormality determination process. Fig. 12 is a diagram showing the current flow when the switching element M2 and the switching element M3 are normal in the solar unit 1 during the third abnormality determination process. Figs. 13A and 13B are diagrams showing the current flow when the switching element M2 or the switching element M3 is abnormal in the solar unit 1 during the third abnormality determination process.

[0046] (Step S1001) The solar control device 50 judges whether the input current of the solar DDC 30 is equal to or greater than the sixth threshold Ith6. This judgment is made to confirm whether the solar panel 10 generates enough power (whether there is a certain amount of solar radiation or more) to perform the abnormality judgment with high accuracy. Therefore, the sixth threshold Ith6 can be appropriately set based on the current required for the third abnormality judgment process. If the input current of the solar DDC 30 is equal to or greater than the sixth threshold Ith6 (step S1001, Yes), the process proceeds to step S1002. On the other hand, if the input current of the solar DDC 30 is less than the sixth threshold Ith6 (step S1001, No), the third abnormality judgment process ends.

[0047] (Step S1002) The solar control device 50 judges the presence or absence of a short circuit fault in the step-down lower arm (switching element M2) and the step-up lower arm (switching element M3) of the solar DDC 30. This step-down lower / step-up lower arm short circuit fault judgment process is performed as follows, as shown in Fig. 11, in a state in which the switching element M1 of the step-down upper arm of the solar DDC 30 is controlled to ON, the switching element M2 of the step-down lower arm and the switching element M3 of the step-up lower arm are controlled to OFF, and the switching element M5 and the switching element M6 of the adjustment circuit 40 are controlled to ON to form a short circuit path.

[0048] If both the switching element M2 of the step-down lower arm and the switching element M3 of the step-up lower arm are normal, a short-circuit current flows from the solar panel 10 to the adjustment circuit 40 as shown in FIG. 12, so that the input current and output current of the solar DDC 30 are equal to the short-circuit current of the solar panel 10. On the other hand, if an abnormality occurs in which the switching element M2 of the step-down lower arm is short-circuited, no short-circuit current flows on the output side of the solar DDC 30 as shown in FIG. 13A. Even if an abnormality occurs in which the switching element M3 of the step-up lower arm is short-circuited, no short-circuit current flows on the output side of the solar DDC 30 as shown in FIG. 13B. Therefore, the solar control device 50 judges the presence or absence of a short-circuit fault in the step-down lower arm and the step-up lower arm based on the following judgment condition 3-1 or 3-2.

[0049] Judgment Criterion 3-1 If the absolute value of the difference between the input current (detection value of the input current detection unit Iin) of the solar DDC 30 and the output current (detection value of the output current detection unit Iout) of the solar DDC 30 exceeds the seventh threshold Ith7 (Equation 4), it is determined that at least one of the step-down lower arm and the step-up lower arm has a short-circuit fault. The seventh threshold Ith7 is set to a predetermined value that is greater than zero and less than the sixth threshold Ith6. |Solar DDC input current - Solar DDC output current |> 7th threshold Ith7 …(Formula 4)

[0050] Judgment condition 3-2 If the output current of the solar DDC 30 (detection value of the output current detection unit Iout) is less than the eighth threshold Ith8 (Equation 5), it is determined that at least one of the step-down lower arm and the step-up lower arm has a short-circuit fault. The eighth threshold Ith8 is set to a predetermined value obtained by adding a determination margin (such as a sensor error) to zero. Solar DDC output current < 8th threshold Ith8 … (Equation 5)

[0051] According to this third abnormality determination process, it is possible to determine a short circuit fault occurring in the step-down lower arm or the step-up lower arm of the solar DDC 30 before the solar charging system is activated and power generation / charging control is started. This makes it possible to grasp a situation in which charging control cannot be performed using the power generated by the solar panel 10. Furthermore, when the solar panel 10 cannot generate sufficient power, the third abnormality determination process is not started, which prevents erroneous determination of a short circuit fault in the step-down lower arm or the step-up lower arm.

[0052] (4) Fourth abnormality judgment process Fig. 14 is a flow chart explaining the fourth abnormality determination process executed by the solar control device 50. Fig. 15 is a diagram showing the state of each switching element of the solar DDC 30 and the adjustment circuit 40 controlled in the fourth abnormality determination process. Fig. 16 is a diagram showing the current flow when the rectifier element D4 is normal in the solar unit 1 during the fourth abnormality determination process. Fig. 17 is a diagram showing the current flow when the rectifier element D4 is abnormal in the solar unit 1 during the fourth abnormality determination process.

[0053] (Step S1401) The solar control device 50 judges whether it is within the second hour since the start of the fourth abnormality judgment process (whether the second hour has not elapsed). This judgment is made to check whether the solar panel 10 is generating enough power to complete the pre-charge process in the next step (whether there is a certain amount of solar radiation or more). The second hour is appropriately set based on the amount of solar radiation that allows pre-charging and the power generation capacity of the solar panel 10. If it is within the second hour since the start of the fourth abnormality judgment process (step S1401, Yes), the process proceeds to step S1402. On the other hand, if it is beyond the second hour since the start of the fourth abnormality judgment process (step S1401, No), the fourth abnormality judgment process ends.

[0054] (Step S1402) The solar control device 50 performs a process of precharging the voltage (output voltage of the solar DDC 30) at the midpoint connecting the solar DDC 30 and the output circuit 20. In this midpoint voltage precharge process, as shown in FIG. 15, the switching element M1 of the step-down upper arm of the solar DDC 30 is controlled to ON, the switching element M2 of the step-down lower arm and the switching element M3 of the step-up lower arm are each controlled to OFF, and the switching element M5 and the switching element M6 of the adjustment circuit 40 are each controlled to OFF. By controlling these switching elements, a charging path from the solar panel 10 to the capacitor C shown by the dashed arrow in FIG. 16 is formed. After the midpoint voltage precharge process is performed, the process proceeds to step S1403.

[0055] (Step S1403) The solar control device 50 judges whether the midpoint voltage (output voltage of the solar DDC 30) has become equal to or greater than the ninth threshold Vth9. This judgment is made to confirm whether the fourth abnormality judgment can be performed. Therefore, the ninth threshold Vth9 is set to a predetermined value equal to or less than the voltage normally stored in the capacitor C. If the midpoint voltage has become equal to or greater than the ninth threshold Vth9 (step S1403, Yes), the process proceeds to step S1404. On the other hand, if the midpoint voltage is less than the ninth threshold Vth9 (step S1403, No), the process proceeds to step S1401.

[0056] (Step S1404) The solar control device 50 judges the presence or absence of a short circuit fault in the boost upper arm (the rectifier element D4) of the solar DDC 30. This boost upper arm short circuit fault judgment process is performed as follows, in a state in which the switching element M1 of the step-down upper arm and the switching element M2 of the step-down lower arm of the solar DDC 30 are controlled to OFF, the switching element M3 of the step-up lower arm is controlled to ON, and the switching element M5 and the switching element M6 of the adjustment circuit 40 are controlled to OFF.

[0057] If the rectifier element D4 of the boost upper arm does not have a short-circuit failure, there is no path for discharging the charge stored in the capacitor C, so the midpoint voltage (output voltage of the solar DDC 30) remains at approximately the pre-charged voltage (only voltage drop due to natural discharge). In contrast, if the rectifier element D4 of the boost upper arm has a short-circuit failure, a current flows between the cathode and anode of the rectifier element D4 as shown in FIG. 17, so the charge stored in the capacitor C is discharged via the switching element M3 of the boost lower arm. Therefore, the midpoint voltage becomes approximately equal to zero. Therefore, the solar control device 50 judges whether or not there is a short-circuit failure in the boost upper arm based on the following judgment condition 4.

[0058] Criterion 4 If the midpoint voltage (the detection value of the output voltage detector Vout) is less than the tenth threshold Vth10 (Equation 6), it is determined that the upper boost arm has a short-circuit fault. The tenth threshold Vth10 is set to a predetermined value that is greater than zero and less than the ninth threshold Vth9. Midpoint voltage < 10th threshold Vth10 ... (Equation 6)

[0059] According to this fourth abnormality determination process, it is possible to determine a short circuit fault occurring in the boost upper arm of the solar DDC 30 before the solar charging system operates and power generation / charging control is started. This makes it possible to avoid a situation in which the output control of the solar panel 10 is not performed normally and the solar panel 10 breaks down. In addition, when a sufficient charge cannot be precharged to the capacitor C (power generation of the solar panel 10 is insufficient), the fourth abnormality determination process is not started, so that it is possible to prevent erroneous determination of a short circuit fault in the boost upper arm.

[0060] [Variation 1] FIG. 18 shows a schematic configuration of a solar unit 2 including a solar DDC 60 of modified example 1. The solar DDC 60 of modified example 1 shown in FIG. 18 has a configuration in which the rectifier element D4 of the boost upper arm in the solar DDC 30 shown in FIG. 1 is replaced with a switching element M4. In the case of a configuration in which a switching element M4 such as a FET is used as the boost upper arm, the switching element M4 is always controlled to be OFF, so that the above-mentioned first to fourth abnormality determination processes can be executed by the rectification action of a body diode (not shown) formed in the FET. FIG. 19 shows the states of the switching elements of the solar DDC 60 and the adjustment circuit 40 of modified example 1 controlled in each of the first to fourth abnormality determination processes.

[0061] [Variation 2] FIG. 20 shows a schematic configuration of a solar unit 3 including a solar DDC 70 of modified example 2. The solar DDC 70 of modified example 2 shown in FIG. 20 is configured by replacing the switching element M2 of the step-down lower arm with a rectifying element D2 in the solar DDC 30 shown in FIG. 1. Even in the case of a configuration in which a rectifying element D2 such as a diode is used as the step-down lower arm, the rectifying element D2 functions in the same way as when the switching element M2 is constantly controlled to be OFF, so that the first to fourth abnormality determination processes described above can be executed. FIG. 21 shows the states of the switching elements of the solar DDC 70 and the adjustment circuit 40 of modified example 2 controlled in the first to fourth abnormality determination processes, respectively.

[0062] [Application example] Fig. 22 shows a schematic configuration of a solar unit 4 of an application example. The solar unit 4 of the application example shown in Fig. 22 differs from the configuration of the solar unit 1 exemplified in Fig. 1 in that it includes a first solar panel 11 and a second solar panel 12, and a first solar DDC 31 and a second solar DDC 32 provided corresponding to the first solar panel 11 and the second solar panel 12. In addition, the first solar DDC 31 and the second solar DDC 32 are provided with a voltage detection unit and a current detection unit on the input side, and an output current detection unit on the output side, respectively. In a solar unit 4 having two systems of solar panels and solar DDCs, as shown in FIG. 23, the first to fourth abnormality determination processes are performed while coordinating the ON / OFF switching control of each switching element M1, M2, and M3 constituting the first solar DDC31 and each switching element M1, M2, and M3 constituting the second solar DDC32, thereby making it possible to determine short circuit faults and open circuit faults in the upper and lower arms in each of the first solar DDC31 and the second solar DDC32.

[0063] In addition, in the solar unit 4 of the application example, by providing an adjustment circuit 40 in each of the first solar DDC 31 and the second solar DDC 32, it becomes possible to independently perform abnormality determination processing for each of the first solar DDC 31 and the second solar DDC 32.

[0064] <Actions and Effects> The solar control device according to the embodiment of the present disclosure described above can determine an open circuit fault in the upper arm as well as a short circuit fault in the step-down upper arm, the step-down lower arm, the step-up upper arm, and the step-up lower arm that constitute the DCDC converter, using the input / output voltage and input / output current values ​​of the DCDC converter and the large-capacity capacitor connected to the midpoint that is the output side of the DCDC converter. This makes it possible to suppress the occurrence of faults in the solar panel and the large-capacity capacitor, and to easily determine a state in which power generation by the solar panel is not possible.

[0065] In addition, the solar control device according to an embodiment of the present disclosure determines whether the solar panel is generating enough power to perform an abnormality determination with high accuracy, and determines whether short circuit failure or open circuit failure of each arm is occurring only when sufficient power is being generated. This makes it possible to prevent erroneous determination of short circuit failure or open circuit failure of an arm when the amount of solar radiation is low.

[0066] The above describes one embodiment of the disclosed technology, but the present disclosure can be understood as not only a solar control device, but also a method performed by the solar control device, a program for that method, a computer-readable non-transitory storage medium storing that program, a solar unit including a solar control device, and a vehicle equipped with that solar unit. [Industrial Applicability]

[0067] The solar control device disclosed herein can be used in DC-DC converters used in solar charging systems that charge batteries using power generated by solar panels, and is particularly useful in situations where it is necessary to easily determine whether a short-circuit or open-circuit fault has occurred. [Explanation of symbols]

[0068] 1, 2, 3, 4 Solar Units 10, 11, 12 Solar panels 20 Output circuit 30, 31, 32, 60, 70 Solar DDC 40 Adjustment circuit 50 Solar Control Device 51 Acquisition Department 52 Control section Vin Input voltage detection section Iin Input current detection section Vout Output voltage detector Iout Output current detection section C Capacitor D2, D4 Rectifier element (diode) L Inductor M1~M6 Switching elements (transistors) R1, R2 resistance

Claims

1. A solar control device that controls a solar unit including a solar panel, a step-up / step-down DC-DC converter that receives power generated by the solar panel, converts the power into a predetermined power, and outputs the converted power, and an adjustment circuit that is used when determining an abnormality in each arm of the DC-DC converter and adjusts the output potential of the DC-DC converter with respect to a ground potential, A voltage acquisition unit that acquires an input voltage and an output voltage of the DC-DC converter; A current acquisition unit that acquires an input current and an output current of the DC-DC converter; A solar control device comprising: a control unit that controls the switching elements and the adjustment circuit that constitute each arm of the DCDC converter, and determines abnormalities in each arm of the DCDC converter based on values ​​acquired by the voltage acquisition unit or the current acquisition unit.

2. The control unit is When the input voltage of the DC-DC converter is equal to or greater than a first threshold, 2. The solar control device according to claim 1, further comprising: a step-down upper arm, a step-down lower arm, and a step-up lower arm of the DC-DC converter, each of the switching elements of which is controlled to be OFF; and a state in which the adjustment circuit is controlled to be a discharge path is continued for a first period of time, and then a determination is made as to whether or not a short-circuit fault has occurred in the step-down upper arm.

3. The solar control device according to claim 2 , wherein the control unit determines that the step-down upper arm has a short-circuit failure when an absolute value of a difference between an input voltage and an output voltage of the DC-DC converter is less than a second threshold value.

4. The solar control device according to claim 2 , wherein the control unit determines that the step-down upper arm has a short-circuit failure when the output voltage of the DC-DC converter exceeds a third threshold value.

5. The control unit is When the input voltage of the DC-DC converter is equal to or higher than a fourth threshold, 2. The solar control device according to claim 1, wherein the switching element of the step-down upper arm of the DCDC converter is controlled to ON, the switching elements of the step-down lower arm and the step-up lower arm are controlled to OFF, and the adjustment circuit is controlled to a short-circuit path, and the presence or absence of an open circuit failure in the step-down upper arm and the step-up upper arm is determined.

6. The solar control device according to claim 5, wherein the control unit determines that at least one of the step-down upper arm and the step-up upper arm has an open circuit fault when the input voltage of the DC-DC converter exceeds a fifth threshold value.

7. The control unit is When the input current of the DC-DC converter is equal to or greater than a sixth threshold, 2. The solar control device according to claim 1, wherein the switching element of the step-down upper arm of the DCDC converter is controlled to ON, the switching elements of the step-down lower arm and the step-up lower arm are controlled to OFF, and the adjustment circuit is controlled to a short-circuit path while determining whether or not the step-down lower arm and the step-up lower arm have a short-circuit failure.

8. The solar control device of claim 7, wherein the control unit determines that at least one of the step-down lower arm and the step-up lower arm has a short-circuit fault when the absolute value of the difference between the input current and the output current of the DC-DC converter exceeds a seventh threshold.

9. The solar control device according to claim 7 , wherein the control unit determines that at least one of the step-down lower arm and the step-up lower arm has a short-circuit failure when the output current of the DC-DC converter is less than an eighth threshold value.

10. The solar unit further includes a storage capacitor connected to an output of the DC-DC converter, The control unit is When the output voltage of the DC-DC converter is equal to or higher than a ninth threshold value in a state in which the switching element of the step-down upper arm of the DC-DC converter is controlled to be ON, the switching elements of the step-down lower arm and the step-up lower arm are controlled to be OFF, and the adjustment circuit is controlled to be open, 2. The solar control device according to claim 1, wherein the switching elements of the step-down upper arm and the step-down lower arm are controlled to be OFF, the switching element of the step-up lower arm is controlled to be ON, and the adjustment circuit is controlled to be open, and the presence or absence of a short-circuit failure of the step-up upper arm is determined.

11. The solar control device according to claim 10, wherein the control unit determines that the boost upper arm has a short-circuit failure when the output voltage of the DC-DC converter is less than a tenth threshold value.

12. A method for controlling a solar unit including a solar panel, a step-up / step-down DC-DC converter that receives power generated by the solar panel, converts the power into a predetermined power, and outputs the converted power, and an adjustment circuit that is used when determining an abnormality in each arm of the DC-DC converter and adjusts an output potential of the DC-DC converter with respect to a ground potential, the method being performed by a solar control device, acquiring an input / output voltage of the DC-DC converter; acquiring an input / output current of the DC-DC converter; and controlling the adjustment circuit and the switching elements constituting each arm of the DCDC converter to determine an abnormality in each arm of the DCDC converter based on values ​​of an input / output voltage or an input / output current.

13. A program executed by a computer of a solar control device to control a solar unit including a solar panel, a step-up / step-down DC-DC converter that inputs power generated by the solar panel, converts the power into a predetermined power, and outputs the converted power, and an adjustment circuit that is used when determining an abnormality in each arm of the DC-DC converter and adjusts the output potential of the DC-DC converter with respect to a ground potential, acquiring an input / output voltage of the DC-DC converter; acquiring an input / output current of the DC-DC converter; and controlling the adjustment circuit and a switching element that configures each arm of the DC-DC converter, and determining an abnormality in each arm of the DC-DC converter based on values ​​of an input / output voltage or an input / output current.

14. A vehicle equipped with the solar control device according to any one of claims 1 to 11.

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