Power systems and estimation methods

Abstract

SOLUTION: Provided are an electric power device and an estimation method, in which an ECU, which is an information processing device, estimates a resistance value Rs from a detection point to a photovoltaic power generator, on the basis of a non-load voltage Voc and non-load current I0 that are detected while a plug and a jack are in a connected state and a voltage Vn and a current In that are detected thereafter.EFFECT: If the resistance value is large, it is possible to grasp that something abnormal has occurred, and a user, as a result, is able to safely use an electric power device.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to Power systems and estimation method In the law .

Background Art

[0002] Patent Document 1 discloses a power device including a power storage unit. The power device outputs the power of the power storage unit to the outside. Further, the power device stores the power supplied from the outside in the power storage unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a photovoltaic power generation system such as a solar power generation system includes a photovoltaic power generation device and a power device. The photovoltaic power generation device is, for example, a solar panel. The photovoltaic power generation device converts light energy into electric power. The power device has a power storage unit. The power device charges the power storage unit with the power output from the photovoltaic power generation device.

[0005] In such a photovoltaic power generation system, there are cases where the power device and the photovoltaic power generation device are not sold as one system, and only the power device is sold. In this case, the user purchases only the photovoltaic power generation device. Therefore, the user can purchase a desired photovoltaic power generation device from the photovoltaic power generation devices sold by many manufacturers. As a result, there is an advantage that the user has more options for the photovoltaic power generation device. However, the ideas regarding the design concept, reliability, etc. of the photovoltaic power generation device vary greatly depending on the manufacturer.

[0006] In this case, when drawing power from a photovoltaic power generator to a power supply unit, it is necessary to connect the connection point of the power supply unit to the connection point of the photovoltaic power generator. Specifically, the power supply unit and the photovoltaic power generator are connected by inserting a plug, which is a connection point on the wiring extending from the photovoltaic power generator, into the jack, which is the connection point of the power supply unit. In this case, the photovoltaic power generator, the wiring extending from the photovoltaic power generator, and the plug on the wiring are commercially available products from different manufacturers than the power supply unit and the jack.

[0007] Therefore, the design tolerances and materials of the contact points between the plug and the jack may differ. Also, when connecting the plug and the jack, if the contact pressure at the contact points is insufficient, or if rust or other corrosion occurs on the surface of the contact points, the contact resistance of the contact points will increase. Furthermore, if the photovoltaic power generation device is damaged by impact or other means, the internal resistance of the photovoltaic power generation device will increase. As a result, when current flows from the photovoltaic power generation device to the power supply device, malfunctions such as overheating of the contact points may occur.

[0008] The present invention aims to solve the problems described above. [Means for solving the problem]

[0009] A first aspect of the present invention is an information processing apparatus, the information processing apparatus comprising: an acquisition unit that acquires current and voltage inside the power device beyond the second connection part detected by the detection unit in a connected state in which a first connection part of a photovoltaic power generation apparatus having a photovoltaic unit and a second connection part of a power device having a detection unit are connected; and an estimation unit that estimates the resistance value from the detection unit to the photovoltaic power generation apparatus based on the current and voltage acquired by the acquisition unit, wherein the estimation unit estimates the resistance value based on a first detected amount which is the current and voltage detected by the detection unit at a first time in the connected state, and a second detected amount which is the current and voltage detected by the detection unit at a second time after the first time.

[0010] A second aspect of the present invention is an information processing apparatus, wherein the information processing apparatus comprises an energy storage unit and lightThe power output device comprises a first connection port of a power output device having at least one of the power generation units and outputting power to the outside, and a second connection port of a power device having a detection unit, and in a connected state in which these are connected, an acquisition unit that acquires the current and voltage inside the power device beyond the second connection port detected by the detection unit, and an estimation unit that estimates the resistance value from the detection unit to the power output device based on the current and voltage acquired by the acquisition unit, wherein the estimation unit estimates the resistance value based on a first detected amount which is the current and voltage detected by the detection unit at a first time in the connected state, and a second detected amount which is the current and voltage detected by the detection unit at a second time after the first time.

[0011] A third aspect of the present invention is an estimation method for estimating a resistance value in a connected state in which a first connection part of a photovoltaic power generation device having a photovoltaic unit is connected to a second connection part of a power device, the estimation method comprising: setting the connection state; detecting voltage and current at a position inside the power device beyond the second connection part during a first time in the connection state; acquiring the current and voltage detected during the first time as a first detected quantity; detecting voltage and current at the position during a second time after the first time; acquiring the current and voltage detected during the second time as a second detected quantity; and estimating the resistance value from the position to the photovoltaic power generation device based on the first detected quantity and the second detected quantity. [Effects of the Invention]

[0014] According to the present invention, the resistance value from the detection points (detection units) of the first and second detected quantities to the photovoltaic power generation device or power output device can be easily estimated. That is, the resistance value including the photovoltaic power generation device or power output device, the connection portion between the first connection portion and the second connection portion, and the wiring between the photovoltaic power generation device or power output device and the power device can be estimated. As a result, if the estimated resistance value is large, it can be easily determined that some kind of malfunction has occurred between the detection unit and the photovoltaic power generation device or power output device. For example, it can be determined that some kind of malfunction has occurred in the connection portion between the first connection portion and the second connection portion. Alternatively, it can be determined that some kind of malfunction has occurred in the photovoltaic power generation device or power output device. As a result, it is possible to avoid malfunctions such as heat generation caused by contact resistance in the connection portion between the first connection portion and the second connection portion, or internal resistance of the photovoltaic power generation device or power output device.

[0015] Thus, in this invention, the resistance value can be accurately estimated using the first and second detected quantities. This allows the user to understand that some kind of abnormality is occurring if the resistance value is high. As a result, the user can use the power device safely. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a diagram showing the configuration of a photovoltaic power generation system. [Figure 2] Figure 2 is a diagram showing the configuration of the power supply unit. [Figure 3] Figure 3 is a circuit diagram of the transformer section. [Figure 4] Figure 4 is a schematic circuit diagram illustrating the resistance present between the power supply device and the photovoltaic power generation device. [Figure 5] Figure 5 is a flowchart of this embodiment. [Figure 6] Figure 6 is a flowchart of this embodiment. [Figure 7] Figure 7 is a flowchart of this embodiment. [Figure 8]FIG. 8 is a graph showing the relationship between the power taken out from the photovoltaic device, the current flowing through the jack, and the voltage of the jack. [Figure 9] FIG. 9 is a graph showing duty up control and duty down control. [Figure 10] FIG. 10 is a graph showing the resistance value estimation process. [Figure 11] FIG. 11 is a circuit diagram of a modified example. [Figure 12] FIG. 12 is a graph showing the resistance value estimation process.

BEST MODE FOR CARRYING OUT THE INVENTION

[0017] FIG. 1 is a configuration diagram of a photovoltaic system 12 including a power device 10. The photovoltaic system 12 includes a power storage unit 14, a power device 10, a photovoltaic device 16, two wirings 18 and 20, and a connector 22.

[0018] The power storage unit 14 is electrically connected to the power device 10. The power storage unit 14 may be externally electrically connected to the power device 10. Alternatively, as shown in FIG. 2, the power storage unit 14 may be mounted or built in the power device 10. The power storage unit 14 may be detachable from the power device 10, or may be fixed to the power device 10.

[0019] When the power storage unit 14 is detachable from the power device 10, the power storage unit 14 is preferably a mobile battery. For example, a lithium-ion battery is suitable. When the power storage unit 14 is detachable from the power device 10, the power device 10 and the power storage unit 14 are connected via a connector. For example, by attaching or detaching a male connector (not shown) of the power device 10 and a female connector (not shown) of the power storage unit 14, the power storage unit 14 can be easily attached to and detached from the power device 10. In the following description, the case where the power storage unit 14 is detachably built in the power device 10 will be described.

[0020] As shown in Figure 1, the photovoltaic power generation device 16 is a photovoltaic power generation device such as a photovoltaic module (PV). The photovoltaic power generation device 16 has a photovoltaic unit 24 such as a cell. The photovoltaic unit 24 is configured by connecting multiple cells in series. The photovoltaic unit 24 converts light energy into DC power. Two wires 18 and 20 extend from the photovoltaic power generation device 16. Plugs 26 (first connection part) of a connector 22 are provided at the ends of the two wires 18 and 20. A jack 28 (second connection part) of the connector 22 is provided on the power device 10. Note that in Figure 1, the plug 26 and jack 28 are schematically shown.

[0021] As shown in Figure 2, the plug 26 has two terminals 30 and 32 that are connected to two wires 18 and 20. The jack 28 has two terminals 34 and 36. The power device 10 and the photovoltaic power device 16 are electrically connected by the connection of the two terminals 30 and 32 of the plug 26 and the two terminals 34 and 36 of the jack 28.

[0022] The photovoltaic power generation device 16 is a commercially available solar cell module. The connector 22 and the two wires 18 and 20 are standard connectors and wires available on the market.

[0023] When the plug 26 and jack 28 are connected, the photovoltaic power generator 16 can output the generated DC power to the power device 10 via two wires 18 and 20.

[0024] The power supply unit 10 is a power supply capable of outputting power to the outside. The power supply unit 10 outputs DC power from the energy storage unit 14 or DC power output from the photovoltaic power generation unit 16 to the outside. Specifically, the power supply unit 10 converts the DC power to AC power using an inverter (not shown) and outputs the converted AC power to the outside. Furthermore, if the power supply unit 10 has a generator (not shown), the power supply unit 10 can output the power generated by the generator to the outside.

[0025] The power device 10 may be a charger that charges the energy storage unit 14 with DC power. In this case, the power device 10 charges the energy storage unit 14 with DC power output from the photovoltaic power generation device 16. Alternatively, the power device 10 may charge the energy storage unit 14 with power generated by a generator or power supplied from an external source.

[0026] As shown in Figure 2, the power device 10 includes an ECU (electronic control unit) 40 as an information processing device according to this embodiment, a transformer unit 42, a fuse 44, and a first temperature measuring unit 46. The transformer unit 42 is electrically connected to the energy storage unit 14. The transformer unit 42 is also connected to two terminals 34 and 36 of the jack 28. A fuse 44 is interposed between the transformer unit 42 and one of the terminals 34 of the jack 28. For convenience, in the following description, the connection portion of the transformer unit 42 to the jack 28 will be referred to as the input side 50. The connection portion of the transformer unit 42 to the energy storage unit 14 will be referred to as the output side 52.

[0027] The ECU40 (information processing unit, acquisition unit, estimation unit, transformer control unit, resistance value determination unit, first temperature determination unit, second temperature determination unit) is a computer that controls each part of the power device 10 and processes various types of information. The ECU40 realizes various functions by reading and executing programs stored in the memory 54 (storage medium).

[0028] When the plug 26 and jack 28 are connected, the ECU 40 controls the transformer 42 to extract DC power from the photovoltaic power generator 16. The transformer 42 controls the voltage of the jack 28 to adjust the magnitude of the DC power extracted from the photovoltaic power generator 16, and stores the adjusted DC power in the energy storage unit 14.

[0029] When the power device 10 functions as a power supply, the transformer unit 42 extracts DC power from the energy storage unit 14 or the photovoltaic power generation device 16. The inverter converts the DC power extracted by the transformer unit 42 into AC power. The converted AC power is output externally. Alternatively, the transformer unit 42 may output the DC power extracted from the energy storage unit 14 or the photovoltaic power generation device 16 externally.

[0030] The first temperature measuring unit 46 sequentially measures the temperature of the jack 28. The first temperature measuring unit 46 sequentially outputs the measurement results to the ECU 40. The energy storage unit 14 has a second temperature measuring unit 56 built into it. The second temperature measuring unit 56 sequentially measures the temperature of the energy storage unit 14. The second temperature measuring unit 56 sequentially outputs the measurement results to the ECU 40.

[0031] Figure 3 is a circuit diagram showing the inside of the transformer unit 42. The transformer unit 42 is a DC / DC converter. When viewed from the photovoltaic power generator 16 to the power device 10, the transformer unit 42 is a boost-type DC / DC converter. That is, the voltage of the energy storage unit 14 is higher than the voltage of the photovoltaic power generator 16 (the voltage of jack 28).

[0032] The transformer unit 42 includes two capacitors 60 and 62, a diode 64, a switching element 66, a coil 68, a current sensor 70 (detection unit), a voltage sensor 72 (detection unit), and a safety switch 74.

[0033] On the other hand, capacitor 60 is electrically connected in parallel to the energy storage unit 14. A series circuit of diode 64 and switching element 66 is electrically connected in parallel to capacitor 60. The cathode of diode 64 is electrically connected to the positive electrode of the energy storage unit 14.

[0034] The switching element 66 is, for example, an N-channel MOSFET. The drain terminal of the switching element 66 is electrically connected to the anode of the diode 64. The source terminal of the switching element 66 is electrically connected to the negative electrode of the energy storage unit 14.

[0035] A control signal is supplied to the gate terminal of the switching element 66 from the ECU 40 (see Figure 2). The control signal is a pulse signal that repeats at a fixed time interval. The switching element 66 turns on and off based on the control signal supplied to the gate terminal. In other words, the ECU 40 controls the on and off of the switching element 66 by PWM (Pulse Width Modulation) control. Therefore, the ECU 40 can arbitrarily adjust the on and off times of the switching element 66 by adjusting the duty cycle of the control signal.

[0036] A series circuit of a coil 68 and a capacitor 62 is electrically connected in parallel to the switching element 66. One end of the coil 68 is electrically connected to the drain terminal of the switching element 66. The other end of the coil 68 is electrically connected to one end of the capacitor 62. The other end of the capacitor 62 is electrically connected to the source terminal of the switching element 66.

[0037] One end of the other capacitor 62 is electrically connected to one terminal 34 of the jack 28 via a current sensor 70 and a safety switch 74. The other end of the other capacitor 62 is electrically connected to the other terminal 36 of the jack 28. A voltage sensor 72 is electrically connected to the two terminals 34 and 36 of the jack 28. When the plug 26 and the jack 28 are connected, the voltage sensor 72 is electrically connected in parallel to the photovoltaic power generator 16.

[0038] Figure 4 is a circuit diagram illustrating the resistance between the power device 10 and the photovoltaic device 16. Figure 4 also shows the equivalent circuit of the photovoltaic device 16. As described above, the photovoltaic unit 24 of the photovoltaic device 16 has a configuration in which multiple cells are connected in series. Therefore, the equivalent circuit of the photovoltaic device 16 shown in Figure 4 is a simplified equivalent circuit for a configuration in which multiple cells are connected in series.

[0039] The photovoltaic power generation device 16 includes a constant current power supply 75, a diode 76, a series resistor 77, and a parallel resistor 78. One end of the series resistor 77 is electrically connected to one of the wirings 18. The other end of the series resistor 77 is electrically connected to one end of the parallel resistor 78. The other end of the parallel resistor 78 is electrically connected to the other wiring 20. The constant current power supply 75 and the diode 76 are electrically connected in parallel to the parallel resistor 78.

[0040] The constant current power supply 75 simulates the constant current sources of multiple cells that make up the photovoltaic unit 24 (see Figures 1 and 2) as a single constant current source. That is, the constant current power supply 75 is a constant current source configured by connecting the constant current sources of multiple cells in series. Each of the multiple constant current sources of the cells is a current source that generates a current corresponding to the amount of solar radiation (light energy). The constant current power supply 75 is a current source that generates a current obtained by summing the currents of these constant current sources.

[0041] Diode 76 simulates the PN junction present in each of the multiple cells as a single diode. Parallel resistor 78 simulates the resistance component resulting from the leakage current at the PN junction in each of the multiple cells as a single resistor. Therefore, parallel resistor 78 simulates the combined resistance of the individual resistance components of the multiple cells as a single resistor. Series resistor 77 simulates the resistance of the connection points that allow the current generated in each of the multiple cells to flow through the wiring 18 and 20 as a single resistor. Therefore, series resistor 77 simulates the combined resistance of the individual connection points of the multiple cells as a single resistor.

[0042] The following resistances exist between the power supply unit 10 and the photovoltaic power generation unit 16. Connector 22 has a contact resistance 80 between terminals 30 and 34 when connecting the plug 26 (see Figures 2 and 3) and the jack 28. Connector 22 also has a contact resistance 82 between terminals 32 and 36 when connecting the plug 26 and the jack 28. The two wires 18 and 20 have a wiring resistance 84. The photovoltaic power generation unit 16 has an internal resistance 86. The internal resistance 86 is the internal resistance of the photovoltaic power generation unit 16 when viewed from the power supply unit 10. The internal resistance 86 includes a series resistance 77 and a parallel resistance 78.

[0043] The operation of the photovoltaic power generation system 12, configured as described above, will be explained with reference to Figures 5 to 10. Figures 1 to 4 will also be referenced as needed during this explanation. Here, we will explain the operation of the power device 10 to extract DC power from the photovoltaic power generation device 16.

[0044] In step S1 of Figure 5, the ECU 40 (see Figures 2 and 3) turns off the safety switch 74. If the plug 26 and jack 28 are connected (step S1: YES), the ECU 40 proceeds to step S2.

[0045] In step S2, the photovoltaic unit 24 (see Figures 1 and 2) of the photovoltaic device 16 converts the energy of light irradiated from the outside (for example, sunlight) into DC power. The photovoltaic device 16 outputs the DC power generated by the photovoltaic unit 24 to the power device 10 via two wires 18 and 20.

[0046] The voltage sensor 72 detects the voltage (voltage V) at jack 28 and outputs the detection result to the ECU 40. In other words, the voltage sensor 72 detects the voltage at the detection point (detection location) as the voltage V at jack 28. The current sensor 70 also detects the current (current I) and outputs the detection result to the ECU 40. In other words, the current sensor 70 detects the current flowing at the detection point (detection location) as the current I flowing through jack 28. The ECU 40 acquires the voltage V detected by the voltage sensor 72 and the current I detected by the current sensor 70 as the first detected quantity.

[0047] As described above, since the safety switch 74 is off, when viewing the power supply 10 from the photovoltaic generator 16, the power supply 10 can be considered to be in an open state. At this time, the photovoltaic generator 16 is in an unloaded state. Therefore, in step S2, the first detected quantities acquired by the ECU 40 are the voltage and current when the photovoltaic generator 16 is in an unloaded state (open state).

[0048] In the following explanation, the voltage V of the first detected quantity will also be referred to as the no-load voltage Voc (first value). The current I of the first detected quantity will also be referred to as the no-load current I0. The current sensor 70 is connected to one terminal 34 of the jack 28 via a safety switch 74 (see Figure 3). As described above, since the safety switch 74 is in the off state, the no-load current I0 is approximately 0.

[0049] In the next step S3, the ECU 40 decides to control the extraction of DC power from the photovoltaic power generator 16 by controlling the transformer unit 42 using the so-called hill-climbing method. Specifically, in step S3, the ECU 40 switches the safety switch 74 from off to on.

[0050] In the next step S4, the ECU40 performs duty-up control, increasing the on-time of the switching element 66 compared to the previous control. As described above, the ECU40 controls the on-off state of the switching element 66 by PWM control. Therefore, duty-up control is a control that increments the on-time of the control signal to turn the switching element 66 on and off.

[0051] In steps S1 to S3, the ECU 40 does not operate the switching element 66; that is, the duty cycle is set to 0. Therefore, in step S4 after step S3, the ECU 40 sets the duty cycle of the control signal to the lowest duty cycle. Next, the ECU 40 supplies the control signal with the set duty cycle to the transformer 42.

[0052] The switching element 66 starts on / off operation based on the supplied control signal. By switching the switching element 66 on and off, the transformer 42 reduces the voltage V at the jack 28, which is the voltage at the input side 50, from the no-load voltage Voc to an arbitrary voltage Vx (second value) (see Figures 8 to 10). More specifically, the transformer 42 reduces the voltage V at the jack 28 from the no-load voltage Voc by lowering the impedance at the input side 50 of the transformer 42 each time the duty cycle of the control signal increases due to PWM control. The transformer 42 increases the current I flowing through the jack 28 from 0 to an arbitrary current Ix each time the duty cycle of the control signal increases. The transformer 42 also boosts the voltage at the output side 52 to the voltage at the energy storage unit 14. As a result, the transformer unit 42 supplies the DC power (power P) output from the photovoltaic power generator 16 to the energy storage unit 14. The energy storage unit 14 stores the supplied DC power.

[0053] In step S5, similar to step S2, the voltage sensor 72 detects the voltage V (voltage Vx) across the jack 28 and outputs the detection result to the ECU 40. The current sensor 70 also detects the current I (current Ix) flowing through the jack 28 and outputs the detection result to the ECU 40. The ECU 40 acquires the voltage V detected by the voltage sensor 72 and the current I detected by the current sensor 70 as a second detection quantity.

[0054] As described above, in step S4, the safety switch 74 was turned on, so when viewing the power supply 10 from the photovoltaic power generator 16, it can be considered that a load exists. In other words, the photovoltaic power generator 16 is in a load state. Therefore, in step S5, the second detected quantities acquired by the ECU 40 are the voltage and current when the photovoltaic power generator 16 is in a load state.

[0055] In the next step S6, the ECU 40 calculates the DC power (power P) extracted from the photovoltaic power generator 16 based on the second detected current I and voltage V (P = V × I).

[0056] In the next step S7, the ECU40 determines whether the calculated power P is greater than the previously calculated power P (previous value). In this case, since there is no previous value, the ECU40 proceeds to step S8.

[0057] In the next step S8, the ECU 40 determines whether the current I of the second detected quantity is greater than the current threshold Imin (see Figure 9). Since control of the transformer 42 by the hill-climbing method has just started, the current I of the second detected quantity is less than or equal to the current threshold Imin (step S8: NO). Therefore, the ECU 40 returns to step S4. After that, the ECU 40 executes the processes of steps S4 to S8 again.

[0058] The ECU 40 executes the processes in steps S4 to S8 at regular intervals. That is, the ECU 40 executes the duty-up control of step S4 at regular intervals. As a result, as shown in Figures 8 and 9, the DC power (power P) extracted from the photovoltaic power generator 16 gradually increases toward the maximum power Pmax. If the voltage V at the point corresponding to the maximum power Pmax is the voltage value Vp, then the voltage V at jack 28 (voltage at the input side 50 of the transformer unit 42) gradually decreases toward the voltage value Vp. The current I flowing through jack 28 (current flowing at the input side 50 of the transformer unit 42) gradually increases.

[0059] Figure 8 shows a graph illustrating the relationship between the power P extracted from the photovoltaic power generator 16 and the voltage V across the jack 28. Power P gradually increases as the voltage V gradually decreases from the no-load voltage Voc. When power P reaches its maximum power Pmax, the voltage V decreases to the voltage value Vp. Furthermore, power P gradually decreases as the voltage V gradually decreases from the voltage value Vp.

[0060] The power P changes depending on the amount of solar radiation reaching the photovoltaic unit 24 (see Figures 1 and 2). When compared at the same voltage V, the power P increases as the amount of solar radiation increases. Figure 8 illustrates the characteristics of three power P values ​​with different amounts of solar radiation. The characteristics of the three power P values ​​are one of the following: maximum power Pmax1 to maximum power Pmax3 (Pmax1 > Pmax2 > Pmax3). The characteristics of power P with maximum power Pmax1 represent the case where the amount of solar radiation is relatively high. The characteristics of power P with maximum power Pmax2 represent the case where the amount of solar radiation is intermediate. The characteristics of power P with maximum power Pmax3 represent the case where the amount of solar radiation is relatively low.

[0061] Figure 8 also shows a graph illustrating the relationship between the voltage V at jack 28 and the current I flowing through jack 28. The current I gradually increases as the voltage V gradually decreases from the no-load voltage Voc. Furthermore, when the voltage V drops to the voltage value Vp, the current I reaches one of the current values ​​Isc1 to Isc3 (Isc1>Isc2>Isc3). Moreover, as the voltage V gradually decreases from the voltage value Vp, the current I is maintained at one of the current values ​​Isc1 to Isc3. In other words, the slope of the current I relative to the voltage V changes abruptly at the voltage value Vp. Note that current values ​​Isc1 to Isc3 are the currents (short-circuit currents) that flow through jack 28 when the photovoltaic power generation device 16 is short-circuited.

[0062] Furthermore, the current I, like the power P, changes depending on the amount of solar radiation to the photovoltaic unit 24. When compared at the same voltage V, the current I increases as the amount of solar radiation increases. Figure 8 illustrates the characteristics of three currents I with different amounts of solar radiation. The characteristics of the three currents I have one of the current values ​​Isc1 to Isc3. The characteristics of current I with current value Isc1 correspond to the characteristics of power P with maximum power Pmax1. The characteristics of current I with current value Isc1 represent the case where the amount of solar radiation is relatively high. The characteristics of current I with current value Isc2 correspond to the characteristics of power P with maximum power Pmax2. The characteristics of current I with current value Isc2 represent the case where the amount of solar radiation is intermediate. The characteristics of current I with current value Isc3 correspond to the characteristics of power P with maximum power Pmax3. The characteristics of current I with current value Isc3 represent the case where the amount of solar radiation is relatively low.

[0063] As shown in Figure 9, the current I actually increases gradually in a curved manner as the voltage V gradually decreases. That is, in the actual characteristics of the current I, the slope of the current I with respect to voltage V is greatest near the no-load voltage Voc. The slope of the current I with respect to voltage V gradually decreases as the voltage V decreases. Also, the slope of the current I with respect to voltage V is smallest near V=0. In this case, the reciprocal of the slope of the current I with respect to voltage V near the no-load voltage Voc represents the resistance value of the series resistor 77 (see Figure 4). Also, the reciprocal of the slope of the current I with respect to voltage V near V=0 represents the resistance value of the parallel resistor 78.

[0064] Figure 8 simply illustrates the characteristics of the actual current I, which changes in a curve (see Figure 9), as a piecewise linear characteristic. Specifically, in Figure 8, regarding the characteristics of current I, in the region from voltage Vp to no-load voltage Voc, current I increases linearly as the voltage V decreases. Furthermore, regarding the characteristics of current I, in the region below voltage Vp, current I is maintained at current values ​​Isc1 to Isc3 regardless of the change in voltage V. Note that in both Figure 8 and Figure 10 (described later), the characteristics of current I are illustrated as a piecewise linear characteristic.

[0065] In step S8 of Figure 5, if the current of the second detected quantity becomes greater than the current threshold Imin (see Figure 9) (step S8: YES), the ECU 40 (see Figure 2) proceeds to step S9.

[0066] In the next step, S9, the ECU40 determines whether duty-up control has been performed three or more times consecutively. If duty-up control has not been performed three or more times consecutively (step S9: NO), the ECU40 returns to step S4. After that, the ECU40 executes the processes of steps S4 to S9 again.

[0067] Subsequently, if duty-up control is performed three or more times consecutively in step S9 (step S9: YES), the ECU 40 proceeds to step S10 in Figure 6.

[0068] In the next step S10, the ECU 40 (see Figure 2) obtains the voltage V (voltage Vn) across the jack 28 from the voltage sensor 72 (see Figure 3). The ECU 40 also obtains the current I (current In) flowing through the jack 28 from the current sensor 70. Therefore, in step S10 as well, the ECU 40 obtains the voltage Vn detected by the voltage sensor 72 and the current In detected by the current sensor 70 as second detected quantities.

[0069] In the next step S11, the ECU 40 calculates the resistance value Rs using the no-load voltage Voc and no-load current I0 obtained in step S2, and the second detected values ​​voltage Vn and current In obtained in step S10. The calculated resistance value Rs is the resistance value of the resistors present from the voltage V and current I detection points (current sensor 70 and voltage sensor 72) to the photovoltaic power generation device 16. Specifically, the resistance value Rs is expressed by the following equation (1). Rs = |(Vn - Voc) / (In - I0)| (1)

[0070] Regarding the characteristics of current I (see Figures 8 to 10), the slope of current I with respect to voltage V near the no-load voltage Voc is the reciprocal of the resistance value Rs. In the region between the voltage value Vp and the no-load voltage Voc, the slope of current I with respect to voltage V between two points, one point with no-load voltage Voc and no-load current I0, and another point with arbitrary voltage Vx and current Ix, can also be approximated by the resistance value Rs.

[0071] In the next step, S12, the ECU40 calculates the average resistance value Rsave, which is the average value of the resistance values ​​Rs. If the process in step S11 is performed for the first time, step S12 is skipped. Alternatively, the resistance value Rs may be temporarily set to the average resistance value Rsave.

[0072] In the next step S13, the ECU40 determines whether the average resistance value Rsave calculated in step S12, or the resistance value Rs calculated in step S11, is less than or equal to the resistance threshold Rth.

[0073] If the average resistance value Rsave or the resistance value Rs is less than or equal to the resistance threshold Rth (step S13: YES), the ECU40 returns to step S4. Then, the ECU40 repeats the processes from steps S4 to S13.

[0074] As a result, within the power device 10, the power P extracted from the photovoltaic power generator 16 increases towards the maximum power Pmax (see Figures 9 and 10). Consequently, the voltage V (voltage Vx) across jack 28 gradually decreases, while the current I (current Ix) flowing through jack 28 gradually increases.

[0075] Furthermore, if duty-up control is performed three or more times consecutively, in step S11, the ECU 40 can calculate the resistance value Rs using the current I (current In) and voltage V (voltage Vn) of the intermediate second detection quantity among three or more second detection quantities acquired at regular intervals, along with the no-load voltage Voc and no-load current I0.

[0076] For example, in Figure 9, as shown by the circles, if three second detection quantities are acquired consecutively at regular intervals, the resistance value Rs is calculated using the current In and voltage Vn of the second detection quantity (indicated by the black circle), along with the no-load voltage Voc and no-load current I0.

[0077] In this way, by using an intermediate second detection quantity, it becomes possible to calculate the resistance value Rs with high accuracy. Furthermore, by comparing the average resistance value Rsave with the resistance threshold Rth in step S13, it becomes possible to make an accurate judgment in step S13.

[0078] In step S13, if the average resistance value Rsave or the resistance value Rs exceeds the resistance threshold Rth (step S13: NO), the ECU 40 determines that there is some kind of malfunction in the connection between the plug 26 and the jack 28, the photovoltaic power generation device 16, etc.

[0079] In other words, as shown in Figure 4, the resistance present from the current sensor 70 (see Figure 3) and voltage sensor 72 to the photovoltaic device 16 consists of the contact resistances 80 and 82 between the plug 26 and the jack 28, the wiring resistance 84 of the two wires 18 and 20, and the internal resistance 86 of the photovoltaic device 16. The wiring resistance 84 and the internal resistance 86 are lower than the contact resistances 80 and 82. Therefore, it can be considered that the majority of the resistance present from the current sensor 70 and voltage sensor 72 to the photovoltaic device 16 is the contact resistance 80 and 82.

[0080] The contact resistances 80 and 82 vary greatly depending on the contact condition between the plug 26 and the jack 28. Specifically, if the plug 26 and the jack 28 are properly connected, the contact resistances 80 and 82 will be low. However, even if the plug 26 and the jack 28 are connected, if the contact pressure is low, the contact resistances 80 and 82 will be high. Alternatively, if there is rust on the surface of the contact terminals 30, 32, 34, and 36, the contact resistances 80 and 82 will be high even if the plug 26 and the jack 28 are connected.

[0081] Furthermore, if the photovoltaic unit 24 is damaged due to an impact on the photovoltaic device 16, the internal resistance 86 will be higher than the wiring resistance 84 and the contact resistances 80 and 82. In this case as well, the average resistance value Rsave or the resistance value Rs may exceed the resistance threshold Rth.

[0082] In Figures 9 and 10, a dashed-dot line (1 / Rth) is shown, representing the reciprocal of the resistance threshold Rth. When the average resistance Rsave or resistance Rs exceeds the resistance threshold Rth, the points representing the second detected quantities, current Ix and voltage Vx, are plotted to the left of this threshold line. In Figure 10, black circles indicate cases where the resistance Rs is less than or equal to the resistance threshold Rth. Also in Figure 10, white circles indicate cases where the resistance Rs exceeds the resistance threshold Rth.

[0083] In step S14 of Figure 6, the ECU 40 (see Figure 2) determines that there is a possibility of malfunctions such as overheating due to contact resistance 80 and 82 (see Figure 4). Next, the ECU 40 stops supplying control signals to the transformer unit 42 and turns off the safety switch 74 (see Figure 3). As a result, the ECU 40 stops controlling the transformer unit 42.

[0084] In the next step S15, the ECU 40 uses a notification unit (not shown), such as a display unit or sound output unit, to notify (warn) the outside that control to the transformer unit 42 has been stopped. This allows the user to recognize that control to the transformer unit 42 has been stopped by checking the notification content. The user can then take appropriate action, such as ensuring that the plug 26 and jack 28 are properly connected. Furthermore, the user can also check the photovoltaic unit 24, plug 26, and jack 28. 28 It is also possible to check whether the item is damaged or deteriorated.

[0085] After a predetermined time has elapsed (step S16: YES), the ECU 40 checks in the next step S17 whether the plug 26 and jack 28 have returned to a normal connection state. For example, if the user connects the plug 26 and jack 28 to a normal state and then operates the control unit (not shown) of the power device 10, the ECU 40 determines, based on the user's operation, that the plug 26 and jack 28 have returned to a normal connection state (step S17: YES). After that, the ECU 40 returns to step S3 and resumes processing from step S3 onward.

[0086] If it is determined that the plug 26 and jack 28 have not returned to a normal connection state (step S17: NO), for example, if no user input is received after a predetermined time has elapsed, the ECU 40 terminates (cancels) the process of extracting DC power from the photovoltaic power generator 16.

[0087] As described above, when duty-up control is performed at regular intervals, the power P extracted from the photovoltaic power generator 16 (see Figures 1 to 4) reaches its maximum power Pmax, as shown in Figure 9. As a result, the voltage V across jack 28 decreases to the voltage value Vp. When the voltage V across jack 28 decreases further, the power P extracted from the photovoltaic power generator 16 decreases from the maximum power Pmax.

[0088] Therefore, it is desirable that the power P extracted from the photovoltaic power generation device 16 be maintained at the maximum power Pmax. As shown in Figure 9, the ECU 40 performs control that continuously searches for the point where the voltage V and current I are such that the power P is at the maximum power Pmax. The ECU 40 (see Figure 2) controls the transformer 42 so that the voltage V of the second detected quantity becomes the voltage value Vp. That is, the maximum power Pmax changes moment by moment due to changes in the amount of sunlight, the partial covering of multiple cells constituting the photovoltaic power generation unit 24 with foreign matter such as leaves, etc. Therefore, the voltage value Vp also changes moment by moment. For this reason, the ECU 40 controls the voltage V to the voltage value Vp by constantly searching for the maximum power Pmax.

[0089] Therefore, if the voltage V across jack 28 decreases and the power P extracted from the photovoltaic generator 16 decreases from the maximum power Pmax, the ECU 40 uses duty-down control to return the voltage V across jack 28 to the voltage value Vp. Duty-down control is a control that reduces the on time of the switching element 66 compared to the previous control. As described above, the ECU 40 controls the on / off state of the switching element 66 by PWM control. Duty-down control is a control that turns the switching element 66 on and off by decrementing the on time of the control signal.

[0090] Specifically, in step S7 of Figure 5, if the power P calculated in step S6 is less than or equal to the previous value (step S7: NO), the ECU 40 proceeds to step S18 of Figure 7. In other words, the ECU 40 (see Figure 2) proceeds to step S18 when the power P calculated in step S6 is less than or equal to the maximum power Pmax.

[0091] In step S18, the ECU 40 performs duty cycle down control. That is, the ECU 40 sets a duty cycle with a shorter on-time than the previous control. Next, the ECU 40 supplies a control signal for the set duty cycle to the transformer 42.

[0092] The switching element 66 performs on / off operations based on the supplied control signal. As a result, the power P increases toward the maximum power Pmax. Consequently, the voltage V across jack 28 gradually increases toward the voltage value Vp.

[0093] In step S19, similar to step S5, the voltage sensor 72 detects the voltage V at jack 28 and outputs the detection result to the ECU 40. The current sensor 70 also detects the current I and outputs the detection result to the ECU 40.

[0094] In step S20, the ECU 40 calculates the power P extracted from the photovoltaic power generator 16 using the second detected current I and voltage V, similar to step S6.

[0095] In step S21, the ECU 40 determines, similar to step S7, whether the calculated power P is greater than the previous value.

[0096] If the calculated power P is less than or equal to the previous value (Step S21: NO) 、 ECU40 returns to step S4 and executes the processes from step S4 onward.

[0097] If the calculated power P is greater than the previous value (step S21: YES), the ECU 40 returns to step S18. Then, the ECU 40 repeats the processes from steps S18 to S21.

[0098] As a result, within the power device 10, the duty-down control increases the impedance of the input side 50, thereby increasing the power P extracted from the photovoltaic power generator 16 toward the maximum power Pmax. Consequently, the voltage V across jack 28 gradually increases, and the current I flowing through jack 28 gradually decreases.

[0099] Note that in the above process, step S8 may be skipped. This allows the ECU40 to calculate the resistance value Rs using a second detected quantity that is close to the no-load voltage Voc and no-load current I0.

[0100] Furthermore, in the above process, the process in step S12 may be skipped. This allows the ECU40 to compare the calculated resistance value Rs with the resistance threshold Rth in step S13.

[0101] Furthermore, in the above process, steps S16 and S17 may be skipped. This allows the ECU 40 to immediately stop the process of extracting DC power from the photovoltaic power generator 16 after the warning process in step S15.

[0102] Furthermore, in the above process, the ECU40 acquires a first detected quantity (no-load voltage Voc, no-load current I0) in step S2, and a second detected quantity (current I(In), voltage V(Vn)) in steps S5 and S10 following step S2. The first and second detected quantities are used in the resistance value Rs estimation process in step S11. In other words, the ECU40 only needs to acquire the first and second detected quantities before step S11. Therefore, in this embodiment, the ECU40 can also perform the processing in step S2 after steps S5 and S10.

[0103] The above description described the case where the power device 10 and the photovoltaic power generation device 16 are connected. In this embodiment, as shown in the modified example in Figure 11, the power device 10 may be connected to a battery 90 (power output device) mounted on a vehicle (not shown). In this case, the power device 10 and the battery 90 may be connected using a plug 26 (see Figure 1) and a jack 28. Alternatively, the power device 10 and the battery 90 may be connected using a commercially available cigarette lighter plug and cigarette lighter socket.

[0104] The battery 90 has extremely low internal resistance compared to the photovoltaic power generator 16. Therefore, the equivalent circuit of the battery 90 is a circuit in which the DC power supply 92 (energy storage unit) is connected to the wiring 18 and 20, as shown in Figure 11.

[0105] In this modified example, the processing shown in Figures 5 to 7 can also be applied. In this case, if the calculated resistance value Rs is less than or equal to a specified value, the ECU40 (see Figure 2) replaces the resistance threshold Rth with a lower resistance value.

[0106] The photovoltaic power generator 16 has an internal resistance 86 (see Figure 4). In contrast, the internal resistance of the battery 90 is negligibly low. Therefore, in this modified example, as soon as the ECU 40 starts duty-up control on the transformer 42 and the battery 90 becomes a load, the current I rapidly increases to the duty-up control current limit value Isc4 (Isc4>Isc1), as shown by the dashed line in Figure 12. The no-load voltage Voc2 is the voltage V at jack 28 when the battery 90 is unloaded.

[0107] In other words, in this modified example, if the determination process in step S13 (see Figure 6) is performed using the resistance threshold Rth1 when the power device 10 and the photovoltaic power generation device 16 are connected, there is a possibility of misjudgment even when the plug 26 (see Figure 1) and the jack 28 are correctly connected. Therefore, in this modified example, by replacing the resistance threshold Rth with Rth2, which is lower than Rth1, the determination process in step S13 can be performed appropriately.

[0108] figure12 In this diagram, the solid line represents the current I flowing through the jack 28 when the power device 10 (see Figure 1) and the photovoltaic power generator 16 are connected. The no-load voltage when the power device 10 and the photovoltaic power generator 16 are connected is Voc1. The dashed line is a threshold line that shows the reciprocal of the resistance threshold Rth1 used in the determination process when the power device 10 and the photovoltaic power generator 16 are connected.

[0109] The dashed line indicates the current I flowing through jack 28 when the power device 10 and battery 90 (see Figure 11) are connected. The current I rises sharply even if the voltage V drops only slightly from the no-load voltage Voc2, and is limited by the current limit value Isc4. The dashed line is a threshold line that shows the reciprocal of the resistance threshold Rth2 used in the judgment process when the power device 10 and battery 90 are connected.

[0110] In Figure 12, the triangle indicates that when the power device 10 is connected to the photovoltaic device 16 (see Figure 1) or the battery 90 (see Figure 11), the resistance value Rs is less than or equal to the resistance threshold Rth1 or resistance threshold Rth2. The white circle indicates that when the power device 10 is connected to the photovoltaic device 16, the resistance value Rs exceeds the resistance threshold Rth1.

[0111] Furthermore, in this embodiment, when the power device 10 and the energy storage unit 14 are connected, the processing shown in Figures 5 to 7 can be applied to determine the resistance value Rs from the current sensor 70 (see Figure 3) and voltage sensor 72 to the energy storage unit 14. In this case as well, if the calculated resistance value Rs is less than or equal to a specified value, the resistance threshold Rth can be replaced with a lower resistance value. In this case, for example, the male connector of the power device 10 can be connected to the female connector of the energy storage unit 14.

[0112] Furthermore, in this embodiment, the energy storage unit and lightWhen a power output device having at least one of the power generation units is connected to the power device 10, it is also possible to apply the processes shown in Figures 5 to 7 to determine the resistance value Rs from the current sensor 70 (see Figure 3) and voltage sensor 72 to the energy storage unit 14. In this case, for example, the jack 28 of the power device 10 can be connected to the plug of the power output device.

[0113] Furthermore, in the processing shown in Figures 5 to 7, ECU40 (figure (See reference 2) If the first temperature measuring unit 46 determines that the temperature of the jack 28 has been measured and exceeds the first temperature threshold, the ECU 40 may stop controlling the transformer unit 42. Also, if the second temperature measuring unit 56 determines that the temperature of the energy storage unit 14 has been measured and exceeds the second temperature threshold, the ECU 40 may stop controlling the transformer unit 42. In either case, the power device 10 can be operated properly.

[0114] In the above description, the cases in which connector 22 is either a plug 26 and a jack 28, or a cigarette lighter plug and a cigarette lighter socket were described. In this embodiment, connector 22 may be any commercially available standard connector.

[0115] The above description describes the case where the ECU 40 within the power unit 10 primarily performs the processing shown in Figures 5 to 7. In this embodiment, detection results such as current I and voltage V may be transmitted to an external information processing device, and various processing may be performed by the external information processing device. That is, an information processing device may be provided outside the power unit 10, and the information processing device may be provided. of It may also function as an ECU40. Examples of such information processing devices include external servers. In this case, the information processing device can be realized using cloud computing or edge computing. In this case, the power device 10 is controlled by the external information processing device. Alternatively, the control function of the transformer unit 42 by the ECU40 may be entrusted to the external information processing device.

[0116] The above description described the case where the transformer unit 42 extracts power P from the photovoltaic power generator 16. In this embodiment, the power generator 10 can also take in power P directly from the photovoltaic power generator 16 without providing the transformer unit 42. In this case, the energy storage unit 14 stores the power P directly.

[0117] Furthermore, the present invention is not limited to the embodiments described above, and various configurations can be taken without departing from the spirit of the invention.

[0118] The inventions that can be understood from the above embodiments are described below.

[0119] A first aspect of the present invention is an information processing device (40), the information processing device comprising: an acquisition unit (40) that acquires current (I) and voltage (V) inside the power device beyond the second connection part detected by the detection unit in a connected state in which a first connection part (26) of a photovoltaic power device (16) having a photovoltaic power generation unit (24) and a second connection part (28) of a power device (10) having detection units (70, 72) are connected; and an estimation unit (40) that estimates the resistance value (Rs) from the detection unit to the photovoltaic power device based on the current and voltage acquired by the acquisition unit, wherein the estimation unit estimates the resistance value based on a first detected amount (Voc, Voc1, I0) which is the current and voltage detected by the detection unit at a first time in the connected state, and a second detected amount (Vn, Vx, In, Ix) which is the current and voltage detected by the detection unit at a second time after the first time.

[0120] According to the present invention, the resistance value from the detection points (detection units) of the first and second detected quantities to the photovoltaic power generation device can be easily estimated. That is, the resistance value including the photovoltaic power generation device, the connection between the first and second connection parts, and the wiring between the photovoltaic power generation device and the power device can be estimated. As a result, if the estimated resistance value is large, it can be easily determined that some kind of malfunction has occurred between the detection unit and the photovoltaic power generation device. For example, it can be determined that some kind of malfunction has occurred in the connection part between the first and second connection parts. Alternatively, it can be determined that some kind of malfunction has occurred in the photovoltaic power generation device. As a result, it is possible to avoid malfunctions such as overheating caused by contact resistance at the connection part between the first and second connection parts, or internal resistance of the photovoltaic power generation device.

[0121] Thus, in this invention, the resistance value can be accurately estimated using the first and second detected quantities. This allows the user to understand that some kind of abnormality is occurring if the resistance value is high. As a result, the user can use the power device safely.

[0122] In a first embodiment of the present invention, the power device further includes a transformer (42) that transforms the voltage of the second connection to take in the power (P) generated by the photovoltaic power generation device, wherein the first detected amount is the current and voltage detected by the detection unit when the transformer transforms the voltage of the second connection so that the voltage of the second connection becomes a first value (Voc) at a first time, and the second detected amount is the current and voltage detected by the detection unit when the transformer transforms the voltage of the second connection so that the voltage of the second connection becomes a second value (Vx) different from the first value at a second time.

[0123] This allows for a more accurate estimation of resistance values, enabling precise detection of any abnormalities. As a result, users can use power equipment safely.

[0124] In a first embodiment of the present invention, the information processing device further comprises a resistance value determination unit (40) that determines whether the resistance value estimated by the estimation unit exceeds a resistance threshold (Rth), and either the information processing device or the power device has a voltage transformer control unit (40) that transforms the voltage of the second connection by controlling the voltage transformer, and if the resistance value determination unit determines that the resistance value exceeds the resistance threshold, the voltage transformer control unit stops controlling the voltage transformer.

[0125] This allows the control of the transformer to be stopped immediately when any malfunction is detected between the detection unit and the photovoltaic power generation device. As a result, malfunctions such as overheating caused by contact resistance can be reliably avoided.

[0126] In a first embodiment of the present invention, the detection unit detects the current and voltage inside the power device beyond the second connection as the current (I) and voltage of the second connection, and the transformer control unit controls the transformer to put the photovoltaic power generation device into an unloaded state, and then puts it into a loaded state in which the voltage of the second connection is lowered and the current is increased, the first time being the unloaded state and the second time being the loaded state.

[0127] This allows for a more accurate estimation of resistance values, enabling a more precise detection of any abnormalities. As a result, users can use power equipment more safely.

[0128] In a first embodiment of the present invention, the estimation unit estimates the resistance value when the current in the second connection is greater than the current threshold (Imin).

[0129] This allows for a more accurate estimation of resistance values.

[0130] In a first embodiment of the present invention, the transformer unit has a switching element (66) that is turned on and off by a control signal from the transformer control unit, and the transformer control unit controls the on / off status of the switching element by changing the duty cycle of the control signal at regular intervals.

[0131] This makes it possible to estimate resistance values ​​more accurately.

[0132] In a first embodiment of the present invention, the transformer control unit performs duty-up control in which, under load conditions, the on-time of the switching element is increased from the previous control at regular intervals.

[0133] This makes it possible to estimate resistance values ​​more accurately.

[0134] In a first embodiment of the present invention, when the duty-up control is performed three or more times consecutively, the estimation unit estimates the resistance value based on the first detected amount and the intermediate second detected amount among the second detected amounts acquired by the acquisition unit at regular intervals.

[0135] This allows for a more accurate estimation of resistance values.

[0136] In a first embodiment of the present invention, the transformer control unit performs the duty-up control when the voltage acquired by the acquisition unit is equal to or greater than a voltage value (Vp) corresponding to the maximum power (Pmax) output from the photovoltaic power generation device.

[0137] This makes it possible to reliably perform the resistance value estimation process.

[0138] In a first embodiment of the present invention, when the voltage acquired by the acquisition unit is lower than the voltage value, the transformer control unit performs duty-down control to reduce the on-time of the switching element compared to the previous control so that the voltage becomes equal to or greater than the voltage value.

[0139] This makes it possible to perform the resistance value estimation process more reliably.

[0140] In a first embodiment of the present invention, the resistance value determination unit replaces the resistance threshold with a lower resistance value when the estimated resistance value is less than or equal to a specified value.

[0141] This allows for appropriate and accurate determination of resistance values, as well as increased reliability of the determination results.

[0142] In a first embodiment of the present invention, the power device further includes a first temperature measuring unit (46) for measuring the temperature of the second connection, and the information processing device further includes a first temperature determination unit (40) for determining whether the temperature measured by the first temperature measuring unit exceeds a first temperature threshold, and if the first temperature determination unit determines that the temperature of the second connection exceeds the first temperature threshold, the transformer control unit stops controlling the transformer.

[0143] This ensures that, in the event of any malfunction at the connection between the first and second connection parts, problems such as overheating caused by contact resistance at the connection between the first and second connection parts can be reliably avoided.

[0144] In a first embodiment of the present invention, the power device further includes a power storage unit (14) capable of storing the power taken in by the transformer unit from the photovoltaic power generation device, and a second temperature measuring unit (56) for measuring the temperature of the power storage unit, and the information processing device further includes a second temperature determination unit (40) for determining whether the temperature measured by the second temperature measuring unit exceeds a second temperature threshold, and if the second temperature determination unit determines that the temperature of the power storage unit exceeds the second temperature threshold, the transformer control unit stops controlling the transformer unit.

[0145] Even in this case, if any abnormality occurs in the energy storage unit, the operation of the power device can be reliably stopped.

[0146] A second aspect of the present invention is an information processing apparatus, wherein the information processing apparatus includes an energy storage unit (92) and light The power output device (90) has at least one of the power generation units and outputs power to the outside, and a first connection part of the power output device (90) has a second connection part of the power device which has a detection unit. In a connected state, the power output device has a first connection part of the power device which has a detection unit, and an acquisition unit which acquires the current and voltage inside the power device beyond the second connection part detected by the detection unit, and an estimation unit which estimates the resistance value from the detection unit to the power output device based on the current and voltage acquired by the acquisition unit. The estimation unit estimates the resistance value based on a first detected amount which is the current and voltage detected by the detection unit at a first time in the connected state, and a second detected amount which is the current and voltage detected by the detection unit at a second time after the first time.

[0147] According to the present invention, the resistance value from the detection point (detection unit) of the first and second detected quantities to the power output device can be easily estimated. That is, the resistance value including the power output device, the connection part between the first connection part and the second connection part, and the wiring between the power output device and the power device can be estimated. As a result, if the estimated resistance value is large, it can be easily determined that some kind of malfunction has occurred between the detection unit and the power output device. For example, it can be determined that some kind of malfunction has occurred in the connection part between the first connection part and the second connection part. Alternatively, it can be determined that some kind of malfunction has occurred in the power output device. As a result, it is possible to avoid malfunctions such as heat generation caused by contact resistance in the connection part between the first connection part and the second connection part, or internal resistance of the power output device.

[0148] Thus, in this invention, the resistance value can be accurately estimated using the first and second detected quantities. This allows the user to understand that some kind of abnormality is occurring if the resistance value is high. As a result, the user can use the power device safely.

[0149] A third aspect of the present invention is an estimation method for estimating a resistance value in a connected state in which a first connection part of a photovoltaic power generation device having a photovoltaic unit is connected to a second connection part of a power device, the estimation method comprising: setting the connection state; detecting voltage and current at a position inside the power device beyond the second connection part during a first time in the connection state; acquiring the current and voltage detected during the first time as a first detected quantity; detecting voltage and current at the position during a second time after the first time; acquiring the current and voltage detected during the second time as a second detected quantity; and estimating the resistance value from the position to the photovoltaic power generation device based on the first detected quantity and the second detected quantity.

[0150] The present invention also provides the same effects as the first and second embodiments. [Explanation of Symbols]

[0155] 10...Power supply unit 14...Energy storage unit 16... Photovoltaic power generation device 24... Photovoltaic power generation unit 26... Plug (first connection point) 28... Jack (second connection point) 40…ECU (Information Processing Unit, Computer, Acquisition Unit, Estimation Unit, Resistance Value Determination Unit, Voltage Transformer Control Unit, First Temperature Determination Unit, Second Temperature Determination Unit) 42...Voltage transformer 46...First temperature measuring unit 54...Memory (storage medium) 56...Second temperature measurement unit 66…Switching element 70…Current sensor (detection unit) 72...Voltage sensor (detection unit) 90...Battery (power output device) 92...DC power supply (power storage unit)

Claims

1. A power device having a second connection part connected to a first connection part of a photovoltaic power generation device having a photovoltaic power generation part, a transformer part, and a detection part, An information processing device having an acquisition unit and an estimation unit, A power system equipped with, The second connection is connected to the input side of the transformer, The detection unit detects the current flowing on the input side of the transformer and also detects the voltage on the input side. The acquisition unit, in a connected state with the first connection unit and the second connection unit connected, acquires the current and voltage detected by the detection unit when the transformer unit transforms the voltage on the input side to take in the power generated by the photovoltaic power generation device into the power device. The estimation unit estimates the resistance value from the detection unit to the photovoltaic power generation device based on the current and voltage acquired by the acquisition unit, and estimates the resistance value based on a first detected amount which is the current and voltage detected by the detection unit at a first time in the connected state, and a second detected amount which is the current and voltage detected by the detection unit at a second time after the first time. Either the information processing device or the power device has a voltage transformer control unit that transforms the input voltage by controlling the voltage transformer, The transformer control unit controls the transformer unit to put the photovoltaic power generation device into an unloaded state, and then puts the voltage of the second connection into a load state that lowers the voltage and increases the current. The voltage transformer has a switching element that is turned on and off by a control signal from the voltage transformer control unit. The transformer control unit controls the on / off state of the switching element by changing the duty cycle of the control signal at regular intervals. The transformer control unit, under the load conditions, performs duty-up control at regular intervals to increase the on-time of the switching element compared to the previous control. The estimation unit estimates the resistance value based on the first detected amount and the intermediate second detected amount among the second detected amounts acquired by the acquisition unit at regular intervals, when the duty-up control is performed three or more times consecutively, in a power system.

2. In the power system according to claim 1, The first detected amount is the current and voltage detected by the detection unit when the transformer unit transforms the voltage on the input side so that the voltage on the input side becomes a first value during the first time period. The power system wherein the second detected amount is the current and voltage detected by the detection unit when the transformer unit transforms the voltage on the input side at a second time such that the voltage on the input side becomes a second value different from the first value.

3. In the power system according to claim 2, The information processing device further includes a resistance value determination unit that determines whether the resistance value estimated by the estimation unit exceeds a resistance threshold, A power system in which, if the resistance value determination unit determines that the resistance value exceeds the resistance threshold, the transformer control unit stops the operation of the transformer by stopping control of the transformer.

4. In the power system according to claim 3, The transformer control unit controls the transformer to put the photovoltaic power generation device into an unloaded state, and then puts the input voltage into a load state that is low and the current is high. The first time mentioned above is when the no-load condition is met. The second time is when the load condition is met, in the power system.

5. In the power system according to claim 4, The power system includes an estimation unit that estimates the resistance value when the current on the input side is greater than a current threshold set to be higher than the current when there is no load.

6. In the power system according to claim 4 or 5, The transformer control unit performs the duty cycle control so that the voltage acquired by the acquisition unit becomes a voltage value corresponding to the maximum power output from the photovoltaic power generation device, in a power system.

7. In the power system according to claim 6, The transformer control unit performs duty-down control, which reduces the on-time of the switching element compared to the previous control, so that when the voltage acquired by the acquisition unit is lower than the voltage value, the voltage becomes the voltage value.

8. In the power system according to any one of claims 3 to 7, The power device further includes a first temperature measuring unit for measuring the temperature of the second connection part, The information processing device further includes a first temperature determination unit that determines whether the temperature measured by the first temperature measurement unit exceeds a first temperature threshold, A power system in which, if the first temperature determination unit determines that the temperature of the second connection exceeds the first temperature threshold, the transformer control unit stops the operation of the transformer by stopping the control of the transformer.

9. In the power system according to any one of claims 3 to 8, The power device further includes a power storage unit connected to the output side of the transformer unit and capable of storing the power taken in by the transformer unit from the photovoltaic power generation device, and a second temperature measuring unit for measuring the temperature of the power storage unit. The information processing device further includes a second temperature determination unit that determines whether the temperature measured by the second temperature measurement unit exceeds a second temperature threshold, A power system in which, if the second temperature determination unit determines that the temperature of the energy storage unit exceeds the second temperature threshold, the transformer control unit stops the operation of the transformer unit by stopping control of the transformer unit.

10. A power device having a second connection part connected to a first connection part of a power output device having at least one of a power storage unit and a photovoltaic unit, a transformer unit, and a detection unit, An information processing device having an acquisition unit and an estimation unit, A power system equipped with, The second connection is connected to the input side of the transformer, The detection unit detects the current flowing on the input side of the transformer and also detects the voltage on the input side. The acquisition unit acquires the current and voltage detected by the detection unit when the power is taken into the power device by the transformer unit transforming the voltage on the input side in a connected state in which the first connection unit and the second connection unit that output power to the outside of the power output device are connected, and the power is taken into the power device by the transformer unit. The estimation unit estimates the resistance value from the detection unit to the power output device based on the current and voltage acquired by the acquisition unit, and estimates the resistance value based on a first detected amount which is the current and voltage detected by the detection unit at a first time in the connected state, and a second detected amount which is the current and voltage detected by the detection unit at a second time after the first time. Either the information processing device or the power device has a voltage transformer control unit that transforms the input voltage by controlling the voltage transformer, The transformer control unit controls the transformer unit to put the power output device into an unloaded state, and then puts the voltage of the second connection into a load state that lowers the voltage and increases the current. The voltage transformer has a switching element that is turned on and off by a control signal from the voltage transformer control unit. The transformer control unit controls the on / off state of the switching element by changing the duty cycle of the control signal at regular intervals. The transformer control unit, under the load conditions, performs duty-up control at regular intervals to increase the on-time of the switching element compared to the previous control. The estimation unit estimates the resistance value based on the first detected amount and the intermediate second detected amount among the second detected amounts acquired by the acquisition unit at regular intervals, when the duty-up control is performed three or more times consecutively, in a power system.

11. An estimation method for estimating resistance values ​​in a connected state where a first connection part of a photovoltaic power generation device having a photovoltaic unit is connected to a second connection part of a power device, The power device has the second connection unit, a voltage transformer, and a detection unit. The second connection is connected to the input side of the transformer, The detection unit detects the current flowing on the input side of the transformer and also detects the voltage on the input side. The estimation method described above is When the first connection part and the second connection part are connected, the transformer transforms the voltage on the input side, and the power generated by the photovoltaic power generation device is taken into the power device, the steps include detecting the voltage and the current during a first time in the connected state, A step of acquiring the current and voltage detected at the first time as the first detected amount, A step of detecting the voltage and the current at a second time after the first time, The steps include acquiring the current and voltage detected at the second time as second detected quantities, A step of estimating the resistance value from the detection unit to the photovoltaic power generation device based on the first detected amount and the second detected amount, It has, Either the information processing device capable of performing the acquisition step and the estimation step, or the power device, has a transformer control unit that transforms the input voltage by controlling the transformer unit. The transformer control unit controls the transformer unit to put the photovoltaic power generation device into an unloaded state, and then puts the voltage of the second connection into a load state that lowers the voltage and increases the current. The voltage transformer has a switching element that is turned on and off by a control signal from the voltage transformer control unit. The transformer control unit controls the on / off state of the switching element by changing the duty cycle of the control signal at regular intervals. The transformer control unit, under the load conditions, performs duty-up control at regular intervals to increase the on-time of the switching element compared to the previous control. In the estimation step, if the duty-up control is performed three or more times consecutively, the estimation method estimates the resistance value based on the first detected amount and the intermediate second detected amount among the second detected amounts acquired at regular intervals.

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