Power control device for on-vehicle solar panel

Abstract

To quickly detect and track the maximum power point in a power control device for an on-vehicle solar panel.SOLUTION: A control unit 28 of a power control device 10 for an on-vehicle solar panel sequentially performs a first search control of each of multiple power conversion units 30 so that the first search control of each power conversion unit 30 is shifted in period from the first search control of the other power conversion units 30. The control unit 28 performs the first search control for each of the multiple power conversion units 30, and then performs a second search control for each of the multiple power conversion units 30 in sequence so that the second search control for each power conversion unit 30 is shifted in period from the second search controls for the other power conversion units 30. The control unit 28 performs tentative tracking control on each power conversion unit 30 to make the power on one side of the power conversion unit 30 track the power based on the first maximum power during the period from the first search control to the second search control.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power control device for an on-vehicle solar panel. [Background technology]

[0002] Patent Document 1 discloses a technology related to a vehicle equipped with a solar panel. In this technology, a control device controls a power converter using a maximum power point tracking (MPPT) method based on the output voltage and output current of the solar panel so that the maximum output power can be obtained from the solar panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-62841 Summary of the Invention [Problem to be solved by the invention]

[0004] The relative position of solar panels mounted on vehicles changes with the movement of the vehicle, and so situations where the sun is blocked by buildings or trees can occur suddenly, and the surrounding environment often changes quickly, for example, between tunnels, buildings, shade, sunlight, etc. In this way, when controlling solar panels whose environments are prone to change suddenly in a short period of time, there is a concern that general MPPT control methods will not be able to search for and track the maximum power point in time, resulting in a decrease in efficiency.

[0005] The present invention has been made to solve at least one of the above-mentioned problems, and has an object to quickly detect and track the maximum power point in a power control device for an on-vehicle solar panel. [Means for solving the problem]

[0006] The power control device for a vehicle-mounted solar panel of the present disclosure includes: A power control device for controlling power input from a plurality of solar panel units, each having one or more solar panels, in a vehicle equipped with a plurality of solar panel units, comprising: A plurality of power conversion units capable of outputting power to the conductive path; A control unit that controls the plurality of power conversion units; a power storage unit that is charged and discharged through the conductive path; having Each of the power conversion units converts input power based on the power supplied from the corresponding solar panel unit to step up or step down the input power, and supplies output power to the conductive path. The control unit repeatedly executes a power adjustment control for each of the power conversion units, the power adjustment control being a search control followed by a tracking control, The search control includes a first search control and a second search control, The first search control is a control for increasing or decreasing a voltage on one of the input side and the output side of the power conversion unit stepwise by a first voltage range, and detecting a first maximum power that is a maximum power among the powers on the one side at each step of the first voltage range, the second search control is a control for increasing the voltage of one side stepwise in a second voltage range smaller than the first voltage range from an intermediate voltage value that is smaller than the voltage value of the one side at the first maximum power in the first search control and larger than the lowest voltage value among the steps of the first search control, or for decreasing the voltage of one side stepwise in the second voltage range from a voltage value that is larger than the voltage value of the one side at the first maximum power in the first search control and smaller than the highest voltage value among the steps of the first search control, and detecting a second maximum power that is the maximum power of the one side at each step of the second voltage range, the tracking control is control for causing the power on the one side of the power converting unit to track the second maximum power detected by the search control, The control unit is performing the first search control of each of the power conversion units in sequence so that the first search control of each of the power conversion units is shifted in time from the first search control of the other power conversion units, and then performing the second search control of each of the power conversion units in sequence so that the second search control of each of the power conversion units is shifted in time from the second search control of the other power conversion units; A tentative tracking control is performed for each of the power conversion units to make the power of the one side track the power based on the first maximum power during the period from the first search control to the second search control. Effect of the Invention

[0007] According to the present disclosure, in a power control device for an in-vehicle solar panel, it is possible to quickly detect and track the maximum power point. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating a schematic configuration of a vehicle including a power control device for an in-vehicle solar panel according to the first embodiment. [Diagram 2] FIG. 2 is a circuit diagram illustrating a schematic example of an MPPT circuit and a control unit included in the power control device of FIG. [Diagram 3] FIG. 3 is a graph showing the relationship between elapsed time and input current, the relationship between elapsed time and input voltage, and the relationship between elapsed time and input power during the first search control. [Figure 4] FIG. 4 is an explanatory diagram illustrating the relationship between the period of one step, the voltage increase width, and the like when the input voltage is increased stepwise during the first search control. [Diagram 5] FIG. 5 is an explanatory diagram illustrating the relationship between the period of one step, the voltage increase width, and the like when the input voltage is increased stepwise during the second search control. [Figure 6] FIG. 6 is the first half of a flowchart showing the flow of processing performed by the control unit. [Figure 7] FIG. 7 shows the second half of the flowchart illustrating the flow of the processing performed by the control unit. [Figure 8] FIG. 8 is a timing chart showing execution timings of the first search control, the tentative tracking control, the second search control, and the tracking control for each power conversion unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiments of the present disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] A power control device for controlling power input from a plurality of solar panel units, each having one or more solar panels, in a vehicle equipped with a plurality of solar panel units, comprising: A plurality of power conversion units capable of outputting power to the conductive path; A control unit that controls the plurality of power conversion units; a power storage unit that is charged and discharged through the conductive path; having Each of the power conversion units converts input power based on the power supplied from the corresponding solar panel unit to step up or step down the input power, and supplies output power to the conductive path. The control unit repeatedly executes a power adjustment control for each of the power conversion units, the power adjustment control being a search control followed by a tracking control, The search control includes a first search control and a second search control, The first search control is a control for increasing or decreasing a voltage on one of the input side and the output side of the power conversion unit stepwise by a first voltage range, and detecting a first maximum power that is a maximum power among the powers on the one side at each step of the first voltage range, the second search control is a control for increasing the voltage of one side stepwise in a second voltage range smaller than the first voltage range from an intermediate voltage value that is smaller than the voltage value of the one side at the first maximum power in the first search control and larger than the lowest voltage value among the steps of the first search control, or for decreasing the voltage of one side stepwise in the second voltage range from a voltage value that is larger than the voltage value of the one side at the first maximum power in the first search control and smaller than the highest voltage value among the steps of the first search control, and detecting a second maximum power that is the maximum power of the one side at each step of the second voltage range, the tracking control is control for causing the power on the one side of the power converting unit to track the second maximum power detected by the search control, The control unit is performing the first search control of each of the power conversion units in sequence so that the first search control of each of the power conversion units is shifted in time from the first search control of the other power conversion units, and then performing the second search control of each of the power conversion units in sequence so that the second search control of each of the power conversion units is shifted in time from the second search control of the other power conversion units; A tentative tracking control is performed on each of the power conversion units to make the power on the one side track the power based on the first maximum power during the period from the first search control to the second search control. Power control device for vehicle-mounted solar panels.

[0011] The power control device performs the detection of the maximum power point relatively roughly by the first search control, and then performs the detection of the maximum power point more precisely by the second search control. In the second search control, the detection of the maximum power point is performed in a voltage region close to the maximum power point detected by the first search control, so that the detection can be performed more quickly than a method of performing the detection in a voltage region equivalent to the first search control. Furthermore, the power control device can concentrate the output from the multiple power conversion units on the conductive path forming the path for charging and discharging the power storage unit. Furthermore, this power control device performs each of the first search controls in sequence with a shift in time from the other first search controls, and performs each of the second search controls in sequence with a shift in time from the other second search controls. Therefore, this power control device can suppress an increase in the control load caused by multiple first search controls being performed simultaneously, and can suppress an increase in the control load caused by multiple second search controls being performed simultaneously. Furthermore, this power control device causes each power conversion unit to make the power of the one side follow the power based on the first maximum power during the period from the first search-and-control to the second search-and-control. Therefore, even while performing each of the first search-and-control in sequence, this power control device can supply power by using the power conversion units in order starting from the power conversion units that have finished the first search-and-control, making it easy to increase the overall power generation capacity.

[0012] [2] The control unit is When the power of the one side detected at the intermediate voltage value in the first search control is equal to or less than a threshold value, the second voltage step is set to a first value in the second search control corresponding to the first search control, and the second search control is started; When the power of the one side detected at the intermediate voltage value in the first search control exceeds the threshold, the second voltage step is set to a value smaller than the first value in the second search control corresponding to the first search control, and the second search control is started. A power control device for an on-vehicle solar panel described in [1].

[0013] The above-mentioned power control device can perform the second search control with a larger voltage step when the power at the start of the second search control is relatively low, and can perform the second search control with a smaller voltage step when the power at the start of the second search control is relatively high.

[0014] [3] The control unit performs the first search control in order from the power conversion unit having the largest power generation capacity of the associated solar panel unit among the plurality of power conversion units. A power control device for an on-vehicle solar panel described in [1] or [2].

[0015] The power control device can perform the first search control by giving priority to the solar panel unit with the largest power generation capacity.

[0016] [Details of the embodiment of the present disclosure] 1. First embodiment 1-1. Overview of in-vehicle systems 1 illustrates an in-vehicle system 1A that is a power control system mounted on a vehicle 1. The in-vehicle system 1A includes a solar panel unit 2, a power control device 10 for an in-vehicle solar panel (hereinafter also referred to as the power control device 10), a battery 6, and a status monitoring device 8. The type of vehicle 1 is not particularly limited, and may be, for example, an electric vehicle or a hybrid vehicle as long as it is a moving object.

[0017] The solar panel unit 2 has one or more solar panels. The solar panel is configured by connecting a plurality of solar cell cells that convert light energy into electric power, and outputs electric power generated by the plurality of solar cell cells in response to irradiated light to the electric power control device 10. The vehicle 1 is provided with a plurality of solar panel units 2. Each of the plurality of solar panel units 2 is electrically connected to the electric power control device 10. Specifically, the plurality of solar panel units 2 include solar panel units 2A, 2B, and 2C. Each of the three solar panel units 2A, 2B, and 2C is disposed at a different position from each other in the vehicle 1, and is disposed in an exposed state. The solar panel unit 2A is electrically connected to a first MPPT circuit 22A (hereinafter, also referred to as MPPT 22A) described later, and can supply electric power to the MPPT circuit 22A. The solar panel unit 2B is electrically connected to a second MPPT circuit 22B (hereinafter also referred to as MPPT 22B) described below, and can supply power to the MPPT circuit 22B. The solar panel unit 2C is electrically connected to a third MPPT circuit 22C (hereinafter also referred to as MPPT 22C) described below, and can supply power to the MPPT circuit 22C.

[0018] The battery 6 is an in-vehicle battery. The battery 6 is, for example, a high-voltage battery capable of supplying power to a drive motor (a motor that powers the wheels of a vehicle). For example, a lithium-ion battery is preferably used as the battery 6. The battery 6 can output a predetermined DC voltage from both ends thereof. The high-potential side electrode of the battery 6 is electrically connected to the second conductive path 61, and the low-potential side electrode of the battery 6 is electrically connected to the second conductive path 62.

[0019] The status monitoring device 8 is configured as a control device equipped with a detection unit, a communication unit, an information processing unit, etc., and has a function of monitoring the status of the battery 6 and a function of communicating with the outside. For example, the status monitoring device 8 has a function of detecting the output voltage (voltage across both ends) of the battery 6 and transmitting the output voltage of the battery 6 to the control unit 28. The output voltage of the battery 6 is the potential difference between the potential of the high potential side electrode, which has the highest potential, and the potential of the low potential side electrode, which has the lowest potential, in the battery 6.

[0020] Although detailed illustration is omitted, the in-vehicle system 1A is provided with a battery management system (BMS) that has functions such as preventing overcharging and over-discharging of the cells that make up the battery 6, preventing overcurrent in the cells, managing the cell temperature, calculating the remaining battery capacity, and equalizing the cell voltages (cell balancing).

[0021] The power control device 10 can receive power from each of the multiple solar panel units 2A, 2B, 2C, and supply output power based on this power to the battery 6. The power control device 10 has a function of controlling the power input from the solar panel unit 2, and can perform voltage step-down and voltage step-up operations internally.

[0022] 1-2. Basic configuration of power control device The power control device 10 includes a plurality of MPPT circuits 22A, 22B, and 22C, a capacitor 24, an isolated converter 26, and a control unit .

[0023] Of the multiple MPPT circuits 22A, 22B, and 22C, the circuit connected to the solar panel unit 2A and receiving power from the solar panel unit 2A is the first MPPT circuit 22A. The circuit connected to the solar panel unit 2B and receiving power from the solar panel unit 2B is the second MPPT circuit 22B. The circuit connected to the solar panel unit 2C and receiving power from the solar panel unit 2A is the third MPPT circuit 22C. The first MPPT circuit 22A, the second MPPT circuit 22B, and the third MPPT circuit 22C have different input connection destinations, but have the same circuit configuration and the same functions. The first MPPT circuit 22A, the second MPPT circuit 22B, and the third MPPT circuit 22C are all controlled by the control unit 28. The following description mainly relates to the first MPPT circuit 22A shown in FIG. 2, but both the MPPT circuits 22B and 22C have the same circuit configuration as the first MPPT circuit 22A.

[0024] The input side conductive paths 11A and 11B are power paths for supplying power based on power generated by the solar panel unit 2A to the power conversion unit 30. The input side conductive path 11A is a conductive path through which an input current based on power supplied from the solar panel unit 2A flows toward the power conversion unit 30, and the input side conductive paths 11A and 11B are conductive paths to which an input voltage based on power supplied from the solar panel unit 2A can be applied. The output side conductive paths 12A and 12B are power paths through which power supplied from the first MPPT circuit 22A is transmitted. The output side conductive path 12A is a conductive path through which an output current supplied from the first MPPT circuit 22A flows. The output side conductive paths 12A and 12B are conductive paths to which an output voltage supplied from the first MPPT circuit 22A can be applied. The input side conductive path 11B and the output side conductive path 12B are conductive paths electrically connected to the ground and have a potential of zero.

[0025] The MPPT circuit 22A includes a power conversion unit 30, and detection units 41 and 42. The MPPT circuit 22A is a circuit that can be controlled by the control unit 28. The MPPT circuit 22A is a circuit that can operate under the control of the control unit 28 in accordance with an MPPT (Maximum Power Point Tracking) method.

[0026] The power conversion unit 30 is configured as a non-insulated DC-DC converter, specifically configured as a known chopper circuit. The power conversion unit 30 is provided between a pair of input side conductive paths 11A, 11B and a pair of output side conductive paths 12A, 12B, and performs a boost operation to boost the input power based on the power supplied from the solar panel unit 2A, and performs power conversion to supply the output power. When the power conversion unit 30 performs the boost operation, based on the input voltage applied between the pair of input side conductive paths 11A, 11B, boosting is performed so that an output voltage higher than the input voltage is applied between the pair of output side conductive paths 12A, 12B. The voltage applied to the input side conductive path 11A is the voltage of the input side conductive path 11A based on the input side conductive path 11B, specifically, the potential difference between the input side conductive paths 11A, 11B. The voltage applied to the output-side conductive path 12A is the voltage of the output-side conductive path 12A with respect to the output-side conductive path 12B, and more specifically, is the potential difference between the output-side conductive paths 12A and 12B.

[0027] 2, the power conversion unit 30 has a circuit configuration capable of step-up operation, but it can also be changed to a circuit configuration capable of step-down operation, or a circuit configuration capable of both step-up and step-down operations. For example, when a circuit configuration in which the power conversion unit 30 performs step-down operation is adopted, the power conversion unit 30 steps down the voltage applied between the pair of input side conductive paths 11A, 11B so as to apply a voltage lower than this voltage between the pair of output side conductive paths 12A, 12B.

[0028] The power conversion unit 30 includes a first element 31, a second element 32, an inductor 34, a drive circuit 38, and the like.

[0029] One end of the inductor 34 is connected to a connection between the first element 31 and the second element 32, and is electrically connected to the anode of the first element 31 and the drain of the second element 32. The other end of the inductor 34 is electrically connected to the input side conductive path 11A (specifically, a portion of the input side conductive path 11A that is closer to the power conversion unit 30 than the detection unit 41). The first element 31 is a diode, and the anode is electrically connected to the inductor 34 and the second element 32, and the cathode is electrically connected to the output side conductive path 12A (specifically, a portion of the output side conductive path 12A that is closer to the power conversion unit 30 than the detection unit 42). The second element 32 is composed of a semiconductor switch element, and is an N-channel MOSFET in the example of FIG. 2. The input side conductive path 11B and the output side conductive path 12B are electrically connected to the source of the second element 32. A drive signal and a non-drive signal are input to the gate of the second element 32 from the drive circuit 38. The second element 32 is turned on when a drive signal (high level signal) is provided to its gate from the drive circuit 38. The second element 32 is turned off when a non-drive signal (low level signal) is provided to its gate from the drive circuit 38.

[0030] Detection unit 41 has a current detection unit and a voltage detection unit. Detection unit 41 is provided midway along input side conductive path 11A. The current detection unit of detection unit 41 provides control unit 28 with a detection value capable of identifying a current value at a detection position of the current detection unit on input side conductive path 11A. The voltage detection unit of detection unit 41 provides control unit 28 with a detection value capable of identifying a voltage value (voltage value between input side conductive paths 11A and 11B) at a detection position of the voltage detection unit on input side conductive path 11A.

[0031] Detection unit 42 has a current detection unit and a voltage detection unit. Detection unit 42 is provided midway along output-side conductive path 12A. The current detection unit of detection unit 42 provides control unit 28 with a detection value capable of identifying a current value at a detection position of the current detection unit on output-side conductive path 12A. The voltage detection unit of detection unit 42 provides control unit 28 with a detection value capable of identifying a voltage value (voltage value between output-side conductive paths 12A and 12B) at a detection position of the voltage detection unit on output-side conductive path 12A.

[0032] The control unit 28 includes, for example, a CPU that performs various arithmetic processing, a storage unit (ROM, RAM, etc.) that stores various information, and a communication unit that is a communication interface for communicating with an external device. The control unit 28 is provided with detection signals from the detection units 41 and 42. The control unit 28 can cause the power conversion unit 30 to perform a voltage step-up operation or a voltage step-down operation. Specifically, the control unit 28 outputs a PWM signal to each of the drive circuits (drive circuit 38 in the first MPPT circuit 22A in FIG. 2) provided in the multiple MPPT circuits 22A, 22B, and 22C. Each drive circuit outputs a PWM signal synchronized with the PWM signal provided to it by the control unit 28.

[0033] The capacitor 24 corresponds to an example of a power storage unit. One electrode of the capacitor 24 is electrically connected to the first conductive path 51, and the other electrode is electrically connected to the first conductive path 52. The capacitor 24 is charged and discharged via the pair of first conductive paths 51, 52. The first conductive path 51 is electrically connected to each of the output side conductive paths 12A, 14A, and 16A so as to be short-circuited thereto. The first conductive path 52 is electrically connected to each of the output side conductive paths 12B, 14B, and 16B so as to be short-circuited thereto.

[0034] The isolated converter 26 is an isolated DC-DC converter. The isolated converter 26 can perform a boost operation of boosting the voltage applied between the pair of first conductive paths 51, 52 and applying a DC voltage to the second conductive paths 61, 62. The isolated converter 26 can perform a step-down operation of stepping down the voltage applied between the pair of second conductive paths 61, 62 and applying a DC voltage to the first conductive paths 51, 52. The isolated converter 26 is controlled by, for example, the control unit 28.

[0035] 1-3. Operation of power control device In the following description, "one side" refers to the solar panel unit 2 side when the power conversion unit 30 is used as a reference, and in the MPPT circuit 22A, it refers to the input side conductive paths 11A, 11B side. "Voltage on one side" refers to the voltage applied between the input side conductive paths 11A, 11B, and "power on one side" refers to the power transmitted by the input side conductive paths 11A, 11B.

[0036] In the power control device 10, the control unit 28 may perform power adjustment control. The power adjustment control is a control that performs search control and then tracking control. The control unit 28 performs search control on the power conversion unit 30 at predetermined fixed time intervals (for example, every 60 to 600 seconds). Then, the control unit 28 performs a tracking control that reflects the search control on the power conversion unit 30 after the search control. Specifically, when the control unit 28 performs search control on the power conversion unit 30 at a certain time, the control unit 28 performs tracking control on the power conversion unit 30 so that the "power on one side" follows the second maximum power P2 obtained in the most recent search control from the end of the search control until the start time of the next search control arrives. The control unit 28 thus repeatedly performs "power adjustment control that performs search control and then tracking control". Then, the search control performed by the control unit 28 includes a first search control and a second search control.

[0037] The first search control is a control that controls the power conversion unit 30 to perform a power conversion operation (specifically, the above-mentioned boost operation) while gradually increasing the voltage (voltage on one side) applied between the input side conductive paths 11A, 11B by a first voltage step-up Δ1, and detects the maximum power (first maximum power) of the input side conductive paths 11A, 11B in all the gradually increased stages based on the power (power on one side) of the input side conductive paths 11A, 11B at each stage when the voltage between the input side conductive paths 11A, 11B is gradually increased by the first voltage step-up Δ1.

[0038] When performing the first search control, the control unit 28 performs on-off control (specifically, PWM control) to give the second element 32 an on-off signal (specifically, a PWM (Pulse Width Modulation) signal) that alternately repeats a drive signal and a non-drive signal, and causes the power conversion unit 30 to perform a boost operation by turning the second element 32 on and off. In this embodiment, in both the search control and the tracking control, the frequency of the PWM signal output by the control unit 28 and the frequency of the PWM signal output by the drive circuit 38 to the second element 32 are 1 kHz or more, and preferably 100 kHz or more. Note that the frequency of the PWM signal is preferably 1000 kHz or less from the viewpoints of high-frequency losses of the switching device and peripheral elements used and EMC (electromagnetic compatibility).

[0039] The control unit 28 controls the power conversion unit 30 to increase the voltage applied between the input side conductive paths 11A and 11B (the voltage on one side) stepwise by a first voltage width Δ1 while causing the power conversion unit 30 to perform a boost operation by such PWM control. During the first search control, the control unit 28 adjusts the duty of the PWM so that the voltage applied between the input side conductive paths 11A and 11B (the voltage on one side) becomes the target voltage at each step. For example, in a situation where the voltage applied between the input side conductive paths 11A and 11B should be V1 during the first search control, the control unit 28 acquires the detection value of the detection unit 41 and monitors the voltage applied between the input side conductive paths 11A and 11B, while adjusting the duty of the PWM signal provided to the gate of the second element 32 so as to maintain the voltage applied between the input side conductive paths 11A and 11B at V1. The control unit 28 sets the length T1 of each period of each step when switching the voltage between the input-side conductive paths 11A and 11B in the first search control to be equal to or longer than 0.05 ms and shorter than 100 ms. In a typical example, T1 is, for example, 1 ms.

[0040] When the initial target voltage immediately after starting the first search control is V1, the control unit 28 adjusts the voltage between the input side conductive paths 11A and 11B to V1 (first stage adjustment) for time T1, then adjusts the voltage between the input side conductive paths 11A and 11B to V1+Δ1 (second stage adjustment), and then adjusts the target voltage by Δ1 to V1+Δ1 (third stage adjustment), and then adjusts the voltage between the input side conductive paths 11A and 11B to V1+Δ1×2. In this way, the control unit 28 causes the power conversion unit 30 to perform the above-mentioned boost operation while stepwise increasing the voltage between the input side conductive paths 11A and 11B every time T1 so that the n-th stage target voltage is V1+Δ1×(n-1).

[0041] The graph in the middle of FIG. 3 is a graph showing the correspondence relationship between the input voltage (the voltage between the input side conductive paths 11A and 11B) and the elapsed time during such a first search control. In the graph in FIG. 3, V1 is the first target voltage, and V4 is the last target voltage among all the steps. That is, in the example of FIG. 3, the voltage is increased stepwise from the voltage value V1 to the voltage value V4 for each Δ1. The graph in the upper part of FIG. 3 is a graph showing the correspondence relationship between the input current (the current flowing through the input side conductive path 11A) and the elapsed time during the first search control. The graph in the lower part of FIG. 3 is a graph showing the correspondence relationship between the input power (the power supplied through the input side conductive paths 11A and 11B) and the elapsed time during the first search control. FIG. 4 is a graph showing the correspondence relationship between the input voltage and the elapsed time during a part of the period during the first search control, and is an explanatory diagram explaining the relationship between the times T1, T2, and Δ1. Δ1 is, for example, a value of 1 / X of the rated voltage or maximum voltage of the solar panel unit 2A that supplies power to the power conversion unit 30. The value of X can be made larger than the number of stages in the above-mentioned first search control. Δ1 is desirably within the range of 1% to 10% of the rated voltage of the solar panel unit 2A, for example.

[0042] The control unit 28 detects the power (power on one side) of the input side conductive paths 11A, 11B at each stage when the voltage between the input side conductive paths 11A, 11B is increased stepwise by a first voltage width Δ1, as shown in the graph in the middle of Fig. 3. Specifically, as shown in Fig. 4, at time T1 of each stage, the power of the input side conductive paths 11A, 11B is detected a predetermined number of times (N times) at a constant sampling interval at time T2 after a predetermined time T3 (T3 = T1 - T2) has elapsed from the start time point t0, and the power detection values ​​of the N times are evaluated using a predetermined statistical method to calculate the power of each stage. The "evaluation using a predetermined statistical method" may be, for example, the average value of the N times, the median value of the N times, the average value excluding the maximum and minimum values ​​of the N times, or another statistical method. In a representative example, an average value of N times is used. For example, in a first stage at time T1 when the voltage of the input side conductive paths 11A and 11B is V1, the power of the input side conductive paths 11A and 11B is detected N times at a constant sampling interval at time T2 after a predetermined time T3 (T3=T1-T2) has elapsed from the start point of the first stage, and the average value of the N power detection values ​​is set as the power value of the first stage (period of voltage value V1). For each period of the second stage, third stage, etc., each power value is calculated in a similar manner. The control unit 28 performs such a first search control for all of the predetermined number of stages, and after each power value of all stages is obtained, the maximum value of each power value of all stages is set as the first maximum power. In the example of the graph in the middle part of FIG. 3, the first maximum power is P1, and the input voltage (voltage of the input side conductive paths 11A and 11B) during the period when this first maximum power P1 is obtained is V3. It should be noted that time T3 is a predetermined percentage of length T1, and the time slot of time T2 is a time slot after a predetermined percentage of length T1 has elapsed in each period.

[0043] After the above-mentioned first search control, the control unit 28 performs the second search control before performing the next tracking control. The second search control is a control that controls the power conversion unit 30 so as to increase the voltage (voltage on one side) between the input side conductive paths 11A, 11B stepwise by a second voltage width Δ2 while making the power conversion unit 30 perform a boosting operation, and detects the maximum power (second maximum power P2) of the input side conductive paths 11A, 11B in all the stepwise increased steps based on the power (power on one side) of the input side conductive paths 11A, 11B at each step when the voltage between the input side conductive paths 11A, 11B is increased stepwise by the second voltage width Δ2. The control of each step of the second search control is the same as the control of each step of the first search control. The second voltage width Δ2 is a value smaller than the first voltage width Δ1, and is preferably in the range of 1% to 50% of Δ1, for example.

[0044] The start voltage value V2 in the second search control is a voltage value (corresponding to an intermediate voltage value) that is smaller than the value V3 of the input voltage (the voltage of the input side conductive paths 11A, 11B) at the first maximum power in the first search control and is larger than the lowest voltage value V1 among the steps of the first search control. In the example of FIG. 3, the start voltage value V2 is a value obtained by lowering the step of the first search control by Z steps from the voltage value V3, and can be expressed by, for example, a formula of V2=V3-Δ1×Z. In the example of FIG. 3, Z is 8, but may be a value other than this. The second search control increases the voltage between the input side conductive paths 11A, 11B (the voltage on one side) stepwise from the start voltage value V2 by a second voltage width Δ2. The control unit 28 also performs the above-mentioned PWM control in the second search control, and causes the power conversion unit 30 to perform a boost operation by providing a PWM signal to the second element 32.

[0045] The control unit 28 controls the power conversion unit 30 to increase the voltage (voltage on one side) between the input side conductive paths 11A and 11B stepwise by the second voltage width Δ2 while causing the power conversion unit 30 to perform a boost operation by such PWM control. The control unit 28 adjusts the duty of the PWM so that the voltage (voltage on one side) between the input side conductive paths 11A and 11B becomes the target voltage at each step even during the second search control. For example, in a situation where the voltage between the input side conductive paths 11A and 11B should be V2 during the second search control, the control unit 28 acquires the detection value of the detection unit 41 to monitor the voltage between the input side conductive paths 11A and 11B, and adjusts the duty of the PWM signal provided to the gate of the second element 32 so as to maintain the voltage between the input side conductive paths 11A and 11B at V2. In the second search control, the control unit 28 also sets the length T1 of each period of each step when switching the voltage between the input side conductive paths 11A and 11B in a stepwise manner to 0.05 ms or more and less than 100 ms. In a typical example, T1 is, for example, 1 ms. The relationship between T1, T2, and Δ2 in the second search control is as shown in FIG. 5.

[0046] When the first target voltage immediately after starting the second search control is V2, the control unit 28 adjusts the voltage between the input side conductive paths 11A, 11B to V2 (first stage adjustment) for time T1, then adjusts the voltage between the input side conductive paths 11A, 11B to V2+Δ2 (second stage adjustment), and then adjusts the target voltage by Δ2 to V2+Δ2 (third stage adjustment), and then adjusts the target voltage by further Δ2 to V2+Δ2×2 (third stage adjustment). In this way, the control unit 28 causes the power conversion unit 30 to perform the above-mentioned boost operation while stepwise increasing the voltage between the input side conductive paths 11A, 11B every time T1 so that the m-th stage target voltage is V2+Δ2×(m-1).

[0047] During the second search control, the control unit 28 detects the power (power on one side) of the input side conductive paths 11A, 11B at each stage when the voltage between the input side conductive paths 11A, 11B is increased stepwise by the second voltage width Δ2. Specifically, as shown in FIG. 5, at time T1 of each stage, the power of the input side conductive paths 11A, 11B is detected a predetermined number of times (N times) at a constant sampling interval at time T2 after a predetermined time T3 (T3=T1-T2) has elapsed from the start time t0, and the power detection values ​​of the N times are evaluated using a predetermined statistical method to calculate the power of each stage. The "evaluation using a predetermined statistical method" may be, for example, an average value of the N times, a median value of the N times, an average value excluding the maximum and minimum values ​​of the N times, or another statistical method. In a representative example, an average value of N measurements is used. For example, at time T1 in the first stage where the voltage between the input side conductive paths 11A and 11B is V2, the power of the input side conductive paths 11A and 11B is detected N times at a constant sampling interval at time T2 after a predetermined time T3 (T3=T1-T2) has elapsed from the start of the first stage, and the average value of the N power detection values ​​is set as the power value of the first stage (period of voltage value V2). For each period of the second stage, third stage, etc., each power value is calculated in a similar manner. The control unit 28 performs such second search control for all stages from voltage values ​​V2 to V4, and after the power values ​​of all stages are obtained, the maximum value of the power values ​​of all stages is set as the second maximum power P2.

[0048] The tracking control is a control for making one side power of the power conversion unit 30 follow the second maximum power P2 detected by the search control. Specifically, it is a control for making the power conversion unit 30 perform a boost operation so that the input power of the power conversion unit 30 (the power supplied via the input side conductive paths 11A and 11B) becomes the above-mentioned power P2. In a situation where the input power supplied via the input side conductive paths 11A and 11B should be set to P2 in the tracking control, the control unit 28 acquires the detection value of the detection unit 41 and monitors the current flowing through the input side conductive path 11A and the voltage between the input side conductive paths 11A and 11B, while adjusting the duty of the PWM signal provided to the gate of the second element 32 so that the input power supplied via the input side conductive paths 11A and 11B becomes P2.

[0049] In the above description, the boosting operation and the step-down operation of the MPPT circuit 22A have been mainly described, but the MPPT circuits 22B and 22C also have a power conversion unit 30, and can perform boosting operation and step-down operation by being controlled by the control unit 28 in the same manner as the MPPT circuit 22A. For example, the MPPT circuit 22B can perform a boosting operation of boosting a voltage applied between a pair of input side conductive paths 13A and 13B and applying it between a pair of output side conductive paths 14A and 14B, and can also perform a step-down operation of boosting a voltage applied between a pair of output side conductive paths 14A and 14B and applying it between a pair of input side conductive paths 13A and 13B. The MPPT circuit 22C can perform a boost operation of boosting the voltage applied across the pair of input side conductive paths 15A, 15B and applying it across the pair of output side conductive paths 16A, 16B, and can also perform a step-down operation of boosting the voltage applied across the pair of output side conductive paths 16A, 16B and applying it across the pair of input side conductive paths 15A, 15B. The control unit 28 can also perform MPPT control on the MPPT circuits 22B, 22C in the same manner as the MPPT circuit 22A.

[0050] The control unit 28 performs the first search control for each of the multiple power conversion units 30 in order so that the first search control for each power conversion unit 30 is shifted in period from the first search control for the other power conversion units 30. The control unit 28 performs the first search control for the power conversion unit 30 among the multiple power conversion units 30 in order starting from the power generation capacity of the associated solar panel unit 2.

[0051] The control unit 28 performs a first search control for each of the multiple power conversion units 30, and then performs a second search control for each of the multiple power conversion units 30 in sequence so that the second search control for each power conversion unit 30 is shifted in period from the second search controls for the other power conversion units 30.

[0052] When the input-side power detected at the intermediate voltage value in the first search control (i.e., the start voltage value V2 in the second search control) is equal to or less than the threshold, the control unit 28 sets the second voltage width to the first value in the second search control corresponding to the first search control and starts the second search control. When the input-side power detected at the intermediate voltage value in the first search control (i.e., the start voltage value V2 in the second search control) exceeds the threshold, the control unit 28 sets the second voltage width to a value smaller than the first value in the second search control corresponding to the first search control and starts the second search control.

[0053] The control unit 28 performs tentative tracking control for making the input-side power track the power based on the first maximum power during the period from the first search control to the second search control for each power conversion unit 30. The power based on the first maximum power may be the first maximum power or a predetermined ratio of the first maximum power.

[0054] The tentative tracking control is a control that causes the power conversion unit 30 to perform a boost operation so that the input power (power supplied via the input side conductive paths 11A, 11B) of the power conversion unit 30 becomes power based on the first maximum power. In a situation where the input power supplied via the input side conductive paths 11A, 11B should be power based on the first maximum power in the tentative tracking control, the control unit 28 acquires a detection value of the detection unit 41 to monitor the current flowing through the input side conductive path 11A and the voltage between the input side conductive paths 11A, 11B, and adjusts the duty of the PWM signal provided to the gate of the second element 32 so that the input power supplied via the input side conductive paths 11A, 11B becomes power based on the first maximum power.

[0055] The control unit 28 performs the first search control of the other power conversion units 30 in parallel with the tentative tracking control of the power conversion unit 30 for which the first search control has been completed first. Also, the control unit 28 performs the tentative tracking control of the other power conversion units 30 in parallel with the power conversion unit 30 for which the second search control has been completed first. Also, the control unit 28 performs the second search control of the other power conversion units 30 in parallel with the tracking control of the power conversion unit 30 for which the second search control has been completed first.

[0056] When it is time to start the search control, the control unit 28 performs the processes shown in Fig. 6 and Fig. 7. In step S10 of Fig. 6, the control unit 28 sets L to 1, and in step S11 performs the first search control of the Lth power conversion unit 30. An order is set for each power conversion unit 30 in advance. In this embodiment, the order of the power conversion units 30 is set in descending order of the power generation capacity of the associated solar panel unit 2. The control unit 28 performs the first search control of the Lth power conversion unit 30 in accordance with the order set in advance in this manner.

[0057] After performing the first search control of the Lth power conversion unit 30, the control unit 28 starts the tentative tracking control of the Lth power conversion unit 30 in step S12. The control unit 28 continues the tentative tracking control of the Lth power conversion unit 30 until immediately before starting the second search control of the Lth power conversion unit 30. After starting the tentative tracking control, the control unit 28 determines in step S13 whether L is the same as the number of power conversion units 30 (three in this embodiment). If the control unit 28 determines that they are not the same, it adds 1 to L in step S14 and returns to step S11. That is, the control unit 28 performs the first search control, and then starts the tentative tracking control for each power conversion unit 30 in turn.

[0058] If the control unit 28 determines in step S13 that L is the same as the number of power conversion units 30 (three in this embodiment), it sets L to 1 in step S20 of Fig. 7. Then, in step S21, the control unit 28 determines whether the input side power detected at the intermediate voltage value in the first search control (i.e., the start voltage value V2 in the second search control) is equal to or less than a threshold value.

[0059] When control unit 28 determines in the first search control that the input-side power detected at the intermediate voltage value is equal to or less than the threshold, it sets the second voltage range to the first value in step S22 and proceeds to step S24. When control unit 28 determines in the first search control that the input-side power detected at the intermediate voltage value exceeds the threshold, it sets the second voltage range to a value smaller than the first value in step S23 and proceeds to step S24.

[0060] The control unit 28 performs the second search control of the Lth power conversion unit 30 in step S24. After performing the second search control of the Lth power conversion unit 30, the control unit 28 starts the tracking control of the Lth power conversion unit 30 in step S25. Thereafter, the control unit 28 determines whether L is the same as the number of the power conversion units 30 in step S26. If the control unit 28 determines that they are not the same, it adds 1 to L in step S27 and returns to step S21. That is, the control unit 28 performs the second search control, and then starts the tracking control for each power conversion unit 30 in order. If the control unit 28 determines that L is the same as the number of the power conversion units 30 in step S26, it ends the processing shown in FIG. 6 and FIG. 7.

[0061] 8, the control unit 28 starts the first search control of the first power conversion unit 30. When the first search control of the first power conversion unit 30 ends, the control unit 28 starts the tentative tracking control of the first power conversion unit 30 and starts the first search control of the second power conversion unit 30. Then, the control unit 28 performs the tentative tracking control of the first power conversion unit 30 and the first search control of the second power conversion unit 30 in parallel.

[0062] When the first search control of the second power conversion unit 30 ends, the control unit 28 starts the tentative tracking control of the second power conversion unit 30 and also starts the first search control of the third power conversion unit 30. Then, the control unit 28 performs the tentative tracking control of the first power conversion unit 30, the tentative tracking control of the second power conversion unit 30, and the first search control of the third power conversion unit 30 in parallel.

[0063] When the first search control of the third power conversion unit 30 ends, the control unit 28 starts the tentative tracking control of the third power conversion unit 30 and starts the second search control of the first power conversion unit 30. Then, the control unit 28 performs the second search control of the first power conversion unit 30, the tentative tracking control of the second power conversion unit 30, and the tentative tracking control of the third power conversion unit 30 in parallel.

[0064] When the second search control of the first power conversion unit 30 ends, the control unit 28 starts the tracking control of the first power conversion unit 30 and also starts the second search control of the second power conversion unit 30. Then, the control unit 28 performs the tracking control of the first power conversion unit 30, the second search control of the second power conversion unit 30, and the tentative tracking control of the third power conversion unit 30 in parallel.

[0065] When the second search control of the second power conversion unit 30 ends, the control unit 28 starts the tracking control of the second power conversion unit 30 and also starts the second search control of the third power conversion unit 30. Then, the control unit 28 performs the tracking control of the first power conversion unit 30, the tracking control of the second power conversion unit 30, and the second search control of the third power conversion unit 30 in parallel.

[0066] When the second search control of the third power conversion unit 30 ends, the control unit 28 starts the tracking control of the third power conversion unit 30. Then, the control unit 28 performs the tracking control of all the power conversion units 30 in parallel.

[0067] 1-4.Examples of effects The power control device 10 performs relatively rough detection of the maximum power point by the first search control, and then performs more precise detection of the maximum power point by the second search control. In the second search control, the maximum power point is detected in a voltage range close to the maximum power point detected by the first search control, so that detection can be performed more quickly compared to a method of detection in the same voltage range as the first search control.

[0068] Furthermore, the power control device 10 can concentrate the outputs from the multiple power conversion units 30 to the first conductive paths 51 and 52 that form a path for charging and discharging the capacitor 24.

[0069] Furthermore, the power control device 10 performs each of the first search controls in sequence with a shift in time from the other first search controls, and performs each of the second search controls in sequence with a shift in time from the other second search controls. Therefore, the power control device 10 can suppress an increase in the control load caused by multiple first search controls being performed simultaneously, and can suppress an increase in the control load caused by multiple second search controls being performed simultaneously.

[0070] Furthermore, the power control device 10 makes the input-side power follow the power based on the first maximum power during the period from the first search-and-control to the second search-and-control for each power conversion unit 30. Therefore, even while performing the first search-and-control for each power conversion unit 30 in sequence, the power control device 10 can supply power by using the power conversion units 30 that have completed the first search-and-control, making it easy to increase the overall power generation capacity.

[0071] When the power at the start of the second search control is relatively low, the power control device 10 can perform the second search control with a larger voltage step, and when the power at the start of the second search control is relatively high, the power control device 10 can perform the second search control with a smaller voltage step.

[0072] The power control device 10 can perform the first search control by giving priority to the solar panel unit 2 having the larger power generation capacity.

[0073] <Other embodiments> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments are also included in the technical scope of the present invention. In addition, the various features of the above-mentioned embodiments and the embodiments to be described later may be combined in any combination as long as they are not contradictory.

[0074] In the above-described embodiment, the power conversion unit 30 is a circuit capable of boosting the voltage applied between the pair of input side conductive paths 11A, 11B to apply a relatively high voltage between the pair of output side conductive paths 12A, 12B, but the power conversion unit 30 may be a circuit capable of lowering the voltage applied between the pair of input side conductive paths 11A, 11B to apply a relatively low voltage between the pair of output side conductive paths 12A, 12B. Even in this case, the control unit 28 can perform MPPT control on the power conversion unit 30.

[0075] In the above embodiment, the control unit 28 periodically performs the search control at regular intervals, but the start timing of the search control is not limited to the regular intervals and may be a timing when another predetermined condition is satisfied. For example, it may be a timing when any of the indicators of the current, voltage, and power on the input side or output side of the power conversion unit 30 changes by a certain value or more during the tracking control, or a timing when the indicator changes suddenly by a certain value or more per unit time.

[0076] In the above embodiment, the pair of input-side conductive paths 11A, 11B side is one side, but the pair of output-side conductive paths 12A, 12B side may be one side. That is, the voltage applied between the output-side conductive paths 12A, 12B may be the voltage of one side, and the power transmitted by the output-side conductive paths 12A, 12B may be the power of one side. In this case, the first search control may be a control that increases the voltage between the output-side conductive paths 12A, 12B stepwise by the above-mentioned first voltage width Δ1, and detects a first maximum power (power that is maximum in the pair of output-side conductive paths 12A, 12B when the voltage between the output-side conductive paths 12A, 12B is switched in multiple steps by the first voltage width Δ1 while the power conversion unit 30 is caused to perform a step-down operation) based on the power of the pair of output-side conductive paths 12A, 12B side (one side) at each step of the first voltage width Δ1. In this case, it differs from the first embodiment in that the voltage to be controlled changes from "the voltage between the input side conductive paths 11A, 11B" to "the voltage between the output side conductive paths 12A, 12B" and that the first maximum power to be detected changes from "the maximum power on the pair of input side conductive paths 11A, 11B" to "the maximum power on the pair of output side conductive paths 12A, 12B", but otherwise is similar to the first search control performed in the first embodiment. In this case, the second search control may be a control that increases the voltage on one side (the voltage between the output-side conductive paths 12A and 12B) stepwise in a second voltage width Δ2 smaller than the first voltage width Δ1 from a voltage value that is smaller than the value of the voltage on one side (the voltage between the output-side conductive paths 12A and 12B) at the first maximum power in the first search control and is larger than the lowest voltage value among the steps of the first search control, and detects the second maximum power based on the power on one side (the power transmitted through the output-side conductive paths 12A and 12B) at each step of the second voltage width Δ2. The first voltage width Δ1 and the second voltage width Δ2 may be the same as those in the first embodiment, or either or both may be different from those in the first embodiment. However, Δ1>Δ2. In this case, the tracking control may be a control that makes the power on one side of the power conversion unit 30 (the power transmitted through the output-side conductive paths 12A and 12B) track the second maximum power detected in the search control.

[0077] In the above-described embodiment, the power conversion unit 30 is configured by a chopper circuit, but may be changed to another DCDC converter capable of step-down and step-up operations, such as a forward-type isolated DCDC converter or a flyback-type isolated DCDC converter.

[0078] In the above-described embodiment, there are no circuits or electrical components between each of the solar panel units 2A, 2B, 2C and each of the MPPT circuits 22A, 22B, 22C, but electrical components and circuits such as relays, fuses, filters, etc. may be provided. The input power input to the power conversion unit 30 may be supplied directly from the solar panel unit 2, or may be supplied via some intermediate circuit.

[0079] In the above description of the embodiment, a driving battery (main battery) consisting of a lithium ion battery has been exemplified as the battery 6, but this is not limited thereto, and the battery 6 may be an auxiliary battery or a lead battery.

[0080] In the above embodiment, an example was shown in which three solar panel units are used and three MPPT circuits are provided, but the number of solar panel units may be two or four or more. In either case, it is sufficient that the MPPT circuits are provided corresponding to the solar panel units.

[0081] In any of the above-mentioned examples of the first embodiment or the above-mentioned examples modified from the first embodiment, the first search control may be "control for stepwise decreasing the voltage of one of the input side and the output side of the power conversion unit by a first voltage width, and detecting a first maximum power that is the maximum power of the power of the one side at each stage of the first voltage width." Specifically, in any of the above-mentioned examples, the power conversion unit 30 may be controlled so as to stepwise decrease the voltage between the input side conductive paths 11A and 11B (the voltage of one side) by a first voltage width Δ1 from the voltage value V4 to the voltage value V1 in FIG. 3 while causing the power conversion unit 30 to perform a power conversion operation, and further, the first search control may be performed so as to detect the maximum power (first maximum power) of the input side conductive paths 11A and 11B in all the steps of the stepwise decrease based on the power (the power of one side) of the input side conductive paths 11A and 11B at each stage when the voltage between the input side conductive paths 11A and 11B is stepwise decreased by the first voltage width Δ1.

[0082] In any of the above-mentioned examples of the first embodiment or the above-mentioned examples modified from the first embodiment, the second search control may be "control for gradually decreasing the voltage on one side by a second voltage width smaller than the first voltage width from a voltage value that is greater than the value of the voltage on one side at the first maximum power in the first search control and smaller than the highest voltage value among the stages of the first search control." Specifically, in any of the above-mentioned examples, the second search control may be performed so as to gradually decrease the voltage on one side by a second voltage width Δ2 smaller than the first voltage width Δ1 from a voltage value that is greater than a value V3 (FIG. 3) of the voltage (voltage on one side) between the input-side conductive paths 11A and 11B at the first maximum power P1 (FIG. 3) in the first search control and smaller than the highest voltage value V4 among the stages of the first search control.

[0083] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0084] 1. Vehicle 1A…In-vehicle system 2, 2A, 2B, 2C...Solar panel section 6…Battery 8...Condition monitoring device 10...Power control device for vehicle-mounted solar panels 11A, 11B, 13A, 13B, 15A, 15B...Input side conductive path 12A, 12B, 14A, 14B, 16A, 16B... Output side conductive path (conductive path) 22...MPPT circuit 22A…First MPPT circuit 22B…Second MPPT circuit 22C…Third MPPT circuit 24...Capacitor (electric storage unit) 26…Isolated converter 28...Control section 30...Power conversion section 31...First element 32...Second element 34…Inductor 38...Drive circuit 41, 42…Detection section 51, 52...First conductive path (conductive path) 61, 62...Second conductive path P1…1st maximum power P2…Second maximum power T3: Predetermined time V1: Voltage value V2: Starting voltage value (middle voltage value) V3…Voltage value V4…Voltage value t0: start time Δ1…First voltage step Δ2: Second voltage step

Claims

1. A power control device for controlling power input from a plurality of solar panel units, each having one or more solar panels, in a vehicle equipped with a plurality of solar panel units, comprising: A plurality of power conversion units capable of outputting power to the conductive path; A control unit that controls the plurality of power conversion units; a power storage unit that is charged and discharged through the conductive path; having Each of the power conversion units converts input power based on the power supplied from the corresponding solar panel unit to step up or step down the input power, and supplies output power to the conductive path. The control unit repeatedly executes a power adjustment control for each of the power conversion units, the power adjustment control being a search control followed by a tracking control, The search control includes a first search control and a second search control, The first search control is a control for increasing or decreasing a voltage on one of the input side and the output side of the power conversion unit stepwise by a first voltage range, and detecting a first maximum power that is a maximum power among the powers on the one side at each step of the first voltage range, the second search control is a control for increasing the voltage of one side stepwise by a second voltage width smaller than the first voltage width from an intermediate voltage value that is smaller than the voltage value of one side at the first maximum power in the first search control and larger than the lowest voltage value among the steps of the first search control, or for decreasing the voltage of one side stepwise by the second voltage width from a voltage value that is larger than the voltage value of one side at the first maximum power in the first search control and smaller than the highest voltage value among the steps of the first search control, and detecting a second maximum power that is the maximum power of the power of one side at each step of the second voltage width; the tracking control is control for causing the power on the one side of the power converting unit to track the second maximum power detected by the search control, The control unit is performing the first search control of each of the power conversion units in sequence so that the first search control of each of the power conversion units is shifted in time from the first search control of the other power conversion units, and then performing the second search control of each of the power conversion units in sequence so that the second search control of each of the power conversion units is shifted in time from the second search control of the other power conversion units; A tentative tracking control is performed on each of the power conversion units to make the power on the one side track the power based on the first maximum power during the period from the first search control to the second search control. Power control device for vehicle-mounted solar panels.

2. The control unit is When the power of the one side detected at the intermediate voltage value in the first search control is equal to or less than a threshold value, the second voltage step is set to a first value in the second search control corresponding to the first search control, and the second search control is started; When the power of the one side detected at the intermediate voltage value in the first search control exceeds the threshold value, the second voltage step is set to a value smaller than the first value in the second search control corresponding to the first search control, and the second search control is started.

2. The power control device for a vehicle-mounted solar panel according to claim 1.

3. The control unit performs the first search control in order from the power conversion unit having the largest power generation capacity of the associated solar panel unit among the plurality of power conversion units.

3. A power control device for an on-vehicle solar panel according to claim 1 or 2.

Images