JP2007147391A - Insulation resistance measurement system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation resistance measuring system capable of reducing the measurement errors of an insulation resistance sensor 5, even if the floating capacitance of a high-voltage part changes according to the state of connection among an electric motor 1, and to provide a fuel cell 2, to and a secondary cell 3. <P>SOLUTION: An insulation resistance measuring system is provided with a high-voltage part comprising at least an electric motor 1; a fuel cell 2 for supplying electric power for the electric motor; a secondary cell 3 for charging and discharging electric power between the electric motor and the fuel cell; and a high-voltage path 4 for electrically connecting between the electric motor, the fuel cell, and the secondary cell; an insulation resistance sensor 5 for measuring the insulation resistance between the high-voltage part and the ground potential; and a cut-off part for cutting off the electric motor, the fuel cell, and the secondary cell from the high-voltage path. A sensor correction part 14 corrects the sensor value that is measured by the insulation resistance sensor, according to the state of connection between the electric motor, the fuel cell, and the secondary cell. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an insulation resistance measurement system that takes into account the stray capacitance of a measurement object.

  In a high voltage system including a high voltage secondary battery as a drive source like an electric vehicle, a vehicle body (ground potential) and a secondary battery (high voltage section) are provided to prevent electric shock from the secondary battery. Generally, the structure is electrically insulated.

  However, there has been a problem that, for example, due to material deterioration or deposits of the secondary battery, the insulation characteristics deteriorate and the vehicle body and the secondary battery are electrically connected.

Therefore, conventionally, an insulation resistance deterioration detection method has been proposed in which the insulation resistance between the vehicle body and the secondary battery is measured in time series to detect the deterioration of the insulation resistance (see, for example, Patent Document 1). . In Patent Document 1, when a stray capacitance is present in a high voltage device such as a secondary battery, the stray capacitance of the high voltage system is inspected in advance, and the sensor value of the insulation resistance is calculated based on a certain correction value calculated from the stray capacitance. (Measurement value) is corrected.
JP 2002-323526 A

  In Patent Document 1, it is assumed that the stray capacitance of the high voltage system does not change. However, in a system in which the stray capacitance changes, an error occurs in the insulation resistance value.

  In particular, since a fuel cell vehicle includes a plurality of units mounted on a high voltage unit such as a fuel cell, an electric motor, and an auxiliary device for driving the fuel cell, the floating capacity is larger than that of an electric vehicle. These fluctuations in the stray capacitance become an error factor of the capacitor coupling type insulation resistance sensor, and the detection accuracy of the insulation resistance value is lowered.

  It is an object of the present invention to suppress a measurement error of an insulation resistance sensor to be small even in a case where a stray capacitance to be measured changes in an insulation resistance measurement system that measures insulation resistance using a capacitor coupling type insulation resistance sensor. .

  The present invention relates to an electric motor, a fuel cell that supplies electric power to the electric motor, a secondary battery that charges and discharges electric power between the electric motor and the fuel cell, an electric motor, a fuel cell, and a secondary battery. A high-voltage unit having at least a high-voltage path that is electrically connected to each other, an insulation resistance sensor that measures an insulation resistance between the high-voltage unit and the ground potential, an electric motor, a fuel cell, and a secondary battery. An insulation resistance measurement system including a cutoff unit that cuts off from a voltage path, wherein the sensor correction unit corrects a sensor value measured by the insulation resistance sensor according to a connection state of the electric motor, the fuel cell, and the secondary battery. It is characterized by that.

  According to the present invention, there is provided an insulation resistance measurement system that suppresses measurement errors of an insulation resistance sensor even when the stray capacitance of a high voltage portion changes according to the connection state of an electric motor, a fuel cell, and a secondary battery. Can do.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[Constitution]
With reference to FIG. 1, an insulation resistance measurement system according to an embodiment of the present invention will be described. Here, a case will be described in which the insulation resistance measurement system is applied to a fuel cell system that generates power by a chemical reaction between a fuel gas and an oxidant gas. Further, an example of a fuel cell vehicle in which the fuel cell system is mounted on a vehicle and used as a vehicle drive source will be described.

  The insulation resistance measurement system includes a high voltage portion to which a high voltage is applied, an insulation resistance sensor 5 that measures the insulation resistance between the high voltage portion and the ground potential, and a high value from the sensor value of the insulation resistance measured by the insulation resistance sensor 5. And a controller 6 for obtaining an insulation resistance value of the voltage section.

  The high voltage unit includes an electric motor 1, a fuel cell 2 that supplies electric power to the electric motor 1, a secondary battery 3 that charges and discharges electric power between the electric motor 1 and the fuel cell 2, an electric motor 1, A high voltage path 4 that electrically connects the fuel cell 2 and the secondary battery 3, a fuel cell side relay 8 that disconnects the connection between the fuel cell 2 and the high voltage path 4, Converter 12 connected between voltage path 4, secondary battery side relay 19 connected between secondary battery 3 and converter 12, compressor 20 for supplying air to fuel cell 2, high voltage The compressor side relay 21 connected between the path 4 and the compressor 20, the low voltage auxiliary machine 22 and the low voltage battery 23 connected to the high voltage path 4, the high voltage path 4, the low voltage auxiliary machine 22, and the low voltage DCDC connected between voltage batteries 23 Inverter 24, low-voltage side relay 25 connected between high voltage path 4 and DCDC converter 24, air conditioner 26 connected to high voltage path 4, and connected between high voltage path and air conditioner 26. The air conditioner side relay 27 is provided.

  The electric motor 1 is used as a drive motor for driving a vehicle. The insulation resistance sensor 5 is grounded to the high voltage path 4.

  Connected to the fuel cell 2 are a circulation path 28 through which a coolant that cools the heat generated in power generation circulates, a radiator 30 that cools the coolant, and a circulation pump 29 that circulates the coolant. Here, the case where the pure water which the fuel cell 2 produces | generates in electric power generation is used as a cooling liquid is demonstrated. A conductivity sensor 10 that detects the conductivity of the pure water is connected to the circulation path 28. The detected conductivity is transmitted to the controller 6.

  The controller 6 corrects the sensor value of the insulation resistance measured by the insulation resistance sensor 5 to reduce the measurement error of the insulation resistance, and calculates the pure water amount from which the amount of pure water is obtained from the generated current of the fuel cell 2. Part 15.

  The sensor correction unit 14 corrects the sensor value measured by the insulation resistance sensor 5 according to the connection state of the electric motor 1, the fuel cell 2, and the secondary battery 3 (hereinafter referred to as “unit”). That is, the sensor value is corrected according to the open / close state of the shut-off unit including the fuel cell side relay 8, the secondary battery side relay 19, the compressor side relay 21, the low voltage side relay 25, and the air conditioner side relay 27. As a result, the sensor value of the insulation resistance can be corrected according to the change in the stray capacitance when each unit connected to the high voltage path is separated by the shut-off unit during the operation including starting and stopping of the fuel cell vehicle. Resistance detection accuracy can be improved.

  The sensor correction unit 14 corrects the sensor value measured by the insulation resistance sensor 5 based on the conductivity value of the coolant that the conductivity sensor 10 calculates. When the conductivity of pure water generated by the fuel cell 2 and circulated for cooling or humidification is lowered, the stray capacitance also changes. Therefore, the detection accuracy of the insulation resistance can be improved by correcting the sensor value according to the conductivity of pure water.

  The sensor correction unit 14 corrects the sensor value based on the amount of pure water calculated by the pure water amount calculation unit 15. Accordingly, the sensor value can be corrected based on the amount of pure water generated from the fuel cell 2. Therefore, even when the amount of pure water produced by the fuel cell 2 changes, the insulation resistance detection error can be reduced.

  As described above, the factors that change the stray capacitance component (the connection state of the high-voltage unit, the conductivity of pure water, and the amount of pure water generated) are examined in advance, and the characteristics that change are stored in the controller 6 for sensor correction. The unit 14 corrects the sensor value of the insulation resistance sensor 5 according to the operation of each device of the fuel cell vehicle.

  The compressor 20, the DCDC converter 24, the low voltage auxiliary machine 22, the low voltage battery 23, and the air conditioner 26 belong to the high voltage auxiliary equipment 13.

  With reference to FIG. 2, the structural example of the insulation resistance sensor 5 of FIG. 1 is demonstrated. The insulation resistance sensor 5 includes a voltage generator 301 that transmits an AC signal such as a sine wave or a rectangular wave, and a waveform detector 302 that receives the AC signal via a resistor and detects the amplitude of the waveform of the AC signal. . The high voltage unit 305 is connected to the voltage generator 301 via a capacitor and a resistor. The high voltage unit 305 is connected to the vehicle body 306 serving as a ground potential via the stray capacitance 304 and the insulation resistance 303.

  The amplitude of the waveform detected by the waveform detector 302 corresponds to the sensor value Am of the insulation resistance measured by the insulation resistance sensor 5. This amplitude has a correlation with the insulation resistance 303 attached to the high voltage unit 305 side. As the amplitude increases, the insulation resistance 303 increases. By examining this characteristic in advance, the insulation resistance R of the high voltage portion 305 can be derived. On the other hand, when the stray capacitance 304 is added to the high voltage unit 305, even if the insulation resistance 303 has the same value, the amplitude of the waveform detector 302 is reduced and the sensor value is output small. This is an error due to stray capacitance. In the case of a device that uses direct current instead of the method using alternating current as in the insulation resistance sensor 5, no measurement error due to the stray capacitance 304 occurs.

[Operation]
With reference to FIG. 3, the measuring method of the insulation resistance by the insulation resistance measuring system of FIG. 1 is demonstrated.

  (A) In step S01, the individual stray capacitance of each unit belonging to the following high voltage section is inspected in advance. As the inspection means, a stray capacitance meter and an LCR meter are used. Then, the individual stray capacitance of each inspected unit is stored in the memory.

Basic state C0
Fuel cell C1
Electric motor C2
Secondary battery C3
Compressor C4
DCDC converter C5
Air conditioner C6
The basic state C0 indicates a state in which the insulation resistance sensor 5 is attached to the fuel cell system, and is a state in which a minimum unit part that cannot be separated is connected. The measurement of the stray capacitance may be performed with the fuel cell system stopped. However, it is desirable that each device is operated by being energized if possible.

  (B) Next, the process proceeds to step S02, and the connection state of each unit is confirmed as shown below. If each unit is connected to the high voltage path 4, ON = 1, and if each unit is disconnected from the high voltage path 4, OFF = 0. The calculated connection status of each unit is stored in the memory.

Fuel cell D1 = 1 or 0
Electric motor D2 = 1 or 0
Secondary battery D3 = 1 or 0
Compressor D4 = 1 or 0
DCDC converter D5 = 1 or 0
Air conditioner D6 = 1 or 0
(C) Proceeding to step S03, the combined stray capacity of the entire fuel cell system is calculated. Using the parameter Dn (n is 1 to 6) indicating the connection state of each unit and the individual stray capacitance Cn (n is 0 to 6) of each unit, the combined stray capacitance (before correction) CA is calculated by the equation (1). Ask.

CA = C0 + D1 × C1 +... + D6 × C6 (1)

(D) Proceeding to step S04, a correction value corresponding to the output current of the fuel cell 2 is calculated. A correction value corresponding to the output current is stored in advance in the memory. A method for obtaining the correction value is described below.

  First, in adapting the correction value according to the output current, the fuel cell vehicle is implemented as a finished product. This is to prevent the occurrence of errors in the case where the stray capacitance inspection is performed with different configurations. In this adaptation method, the test is performed by actually grounding the insulation resistance in the fuel cell vehicle. Prepare the following before the test.

  Waveform calculation is performed by a circuit simulator using the insulation resistance sensor 5, the insulation resistance 303 that simply represents the ground fault state of the fuel cell vehicle, and the stray capacitance 304 shown in FIG. 2. This waveform calculation can be calculated by general circuit calculation software, and it is easy to obtain them. This software allows the internal configuration of the insulation resistance sensor 5 to be expressed. The amplitude value of the waveform detected by the waveform detector 302 when the values of the insulation resistance 303 and the stray capacitance 304 are changed is calculated. The relationship between the amplitude value (sensor value), the insulation resistance 303 and the stray capacitance 304 is shown in FIG.

  In the result example shown in FIG. 5, the amplitude value when the insulation resistance R is changed on the horizontal axis = sensor value is recorded, and the stray capacitance C shows sensor characteristics under a plurality of conditions. It is preferable that there are as many calculation points as possible, and the accuracy of the correction value table created using this simulation result can be improved by setting and obtaining the conditions of the stray capacitance C at fine intervals.

  (E) Returning to the description of the main flow in FIG. 3, the process proceeds to step S05 to check whether the fuel cell 2 is connected (D1 = 1). If connected (YES in step S05), the process proceeds to step S06. If disconnected (NO in step S05), the process ends.

  (F) In step S06, correction according to the conductivity of pure water used for cooling and humidification in the fuel cell 2 is performed. A method for creating a correction table used in step S06 will be described. First, in a state where the conductivity of pure water is very low, the variable resistor 41 is connected to the high voltage path 4 as shown in FIG. In this state, the insulation resistance of the vehicle is measured with a mega ohm tester or the like. This insulation resistance value is defined as insulation resistance A. The relationship between the sensor value at this time and the insulation resistance of the entire vehicle measured with a DC resistance meter is recorded.

  Next, assuming that the conductivity of pure water is increased due to impurities or the like, the measurement is performed under the condition of maximum conductivity. It should be noted that the variable resistor 41 is adjusted so as to have the same value as the insulation resistance A measured by the mega ohm tester. When the variable resistance 41 is adjusted and the insulation resistance measured by the mega ohm tester is confirmed to be the same value as the insulation resistance A, the sensor value at that time is recorded.

  The above relationship will be described with reference to FIG. When the conductivity of pure water is low, the plot point 61 is obtained. If the variable resistance 41 is left as it is and the state of conductivity is high, the insulation resistance of the vehicle also decreases and the result of the plot point 62 is obtained. Since the plot points 61 and 62 cannot be compared as they are, the variable resistor 41 is adjusted and moved to the plot point 63 where the insulation resistance becomes the insulation resistance A.

  From the comparison of the plot points 61 and 63, it is possible to know the difference in sensor value when the insulation resistance A is the same and the conductivity of pure water is different. Similar to the creation of the correction table according to the output current at step S04, the difference obtained by subtracting the capacitance value in the state of low conductivity from the capacitance in the case of high conductivity is used as the correction amount. By increasing the insulation resistance conditions to be compared in the same way, the set point of the correction table can be increased. With the above procedure, a correction table corresponding to the conductivity of pure water as shown in FIG. 4A can be created. Using this correction table, the correction amount Cws of the stray capacitance in step S06 is calculated.

  (G) Next, in step S07, a correction value is calculated according to the amount of pure water generated when the fuel cell generates power. First, in order to adapt the correction value, the fuel cell vehicle is implemented as a finished product. This is to prevent the occurrence of errors in the case where the stray capacitance inspection is performed with different configurations. In addition, in correcting based on the amount of pure water, the amount of pure water generated is estimated. In the present embodiment, the fact that the amount of pure water generated and the amount of hydrogen used are proportional is utilized, and the fact that the amount of hydrogen used is proportional to the generated current is utilized. Therefore, the correction amount is calculated by estimating the pure water generation amount from the generated current.

  A method for creating a correction table according to the amount of pure water generated will be described. This test is performed by actually grounding the insulation resistance in a fuel cell vehicle. The state of the fuel cell vehicle to be tested is shown in FIG. FIG. 6 shows an example of test conditions, and a configuration in a normal state in which the fuel cell 2 can generate power in a fuel cell vehicle may be used. The high voltage part of the fuel cell vehicle is grounded with the variable resistor 41 interposed therebetween. The variable resistance 41 is matched with the resistance value within the measurement range of the insulation resistance sensor 5 within the range of the insulation resistance to be measured. In this state, the insulation resistance of the fuel cell vehicle is measured with a DC-type resistance sensor. Next, the vehicle is started with the variable resistor 41 attached, and the sensor value when the fuel cell 2 is kept in the idle state is recorded. Further, the output of the fuel cell 2 is increased, and the sensor value and the output current are recorded.

  After the recording is completed, the difference in stray capacitance between the idle state and the output state of the fuel cell 2 is calculated in the same insulation resistance state. FIG. 8 shows a case where, for example, the condition of the insulation resistance B is selected as the condition for grounding the insulation resistance by the variable resistance 41. The stray capacitance C in the idle state and the output state is obtained using FIG. On the dotted line 71 of the insulation resistance B, a plot point 72 and a plot point 73 of the measurement result are obtained. The value of the stray capacitance is obtained by confirming which stray capacitance C line each plot point 72 and plot point 73 is on. The plot point 72 is C = CT2, and the plot point 73 is C = CT4.

  The above calculation is performed for each measured condition to obtain the stray capacitance for each output current. Thereafter, a correction table corresponding to the amount of pure water used in step S07 is created by subtracting the idle stray capacitance from the stray capacitance for each output current. In the correction table, the difference with respect to the idle state is calculated. With the above procedure, a correction table corresponding to the amount of pure water produced (fuel cell current) as shown in FIG. 4B can be created. Using this correction table, the correction amount Cwt in step S07 is calculated.

  (H) Proceeding to step S08, the correction values (Cws, Cwt) calculated in steps S06 and S07 are added to the combined capacitance CA calculated in step S03 to obtain a corrected combined capacitance CA1.

  (I) Proceeding to step S09, the insulation resistance is calculated from the combined capacitance CA1 and the sensor value Am based on the table of FIG.

  Next, a method for creating the insulation resistance calculation table shown in FIG. There are several methods, but the sensor value = amplitude value and the values of the insulation resistance and capacitance calculated by the circuit simulator can be used as a table as they are. In this case, an error due to the influence of the high voltage portion of an actual fuel cell vehicle is not included, but it can be used if this error is at a negligible level. As for the degree of error, the difference between the insulation resistance value actually measured by the DC resistance meter and the insulation resistance value obtained from the output of the insulation resistance sensor 5 in the start-up state of the fuel cell vehicle is compared. Judgment.

  The following method is effective when the accuracy needs to be further increased. In advance, the insulation resistance of the vehicle is measured with a DC insulation resistance meter while the fuel cell vehicle is in operation. In addition, stray capacitance is also measured in advance. In either case, when measurement in the activated state is difficult, measurement in the unactivated state may be used. However, it is better that the connected part is as close to the activated state as possible. Next, as shown in FIG. 6, the variable resistor 41 is connected, the variable resistor 41 is changed from 0 kΩ to the maximum of the measurement range, and the sensor value of the insulation resistance sensor 5 at that time is recorded. When the recording is completed, the insulation resistance value and the combined resistance of the fuel cell vehicle in which the fuel cell vehicle measured in advance is calculated based on the value of the variable resistance 41 corresponding to the sensor value, and the relationship between the combined resistance and the sensor value is tabulated. . This is the basic table. This basic table corresponds to C = CE1 shown in FIG. Next, a table (C = CE2) and a table (C = CE3) when the stray capacitance increases are obtained.

  Next, the result of the circuit simulation shown in FIG. 9 is prepared, and a table line corresponding to the stray capacitance CE1 measured in the activated state is selected. There is a difference between the result of the stray capacitance CE1 of the simulation result and the result of the basic table (C = CE1) obtained by the actual measurement due to the difference between the calculation and the actual measurement.

  In order to minimize this error, the influence of the stray capacitance obtained in the simulation is added to the basic table (C = CE1). The effect of stray capacitance can be expressed by using the base value as the actual measurement method and the difference as the calculated value.

  The actual creation method will be described with reference to FIG.

  (1) First, the stray capacitance corresponding to the stray capacitance CE1 (= CT1) in the basic table is selected from the simulation result.

  (2) The difference (RD-RC) between the plot point 803 of the basic table (CT1) and the plot point 804 on the stray capacitance CT4 is obtained with the same sensor value.

  (3) The difference (RD-RC) of the stray capacitance CT4 with respect to the stray capacitance CT1 is added to the specific table (dotted line 802) of the stray capacitance CE1 obtained by actual measurement.

  By repeating the above procedure, CT2 to CTn can be tabulated. Based on the table of FIG. 4C created in this way, the insulation resistance is calculated from the sensor value of the insulation resistance and the combined stray capacitance.

[effect]
As described above, according to the embodiment of the present invention, the following effects can be obtained.

  The sensor correction unit 14 measures the insulation resistance sensor 5 according to the connection state (relay open / close state) of each unit constituting the high voltage unit, that is, the electric motor 1, the fuel cell 2, and the secondary battery 3. Correct the sensor value. As a result, the sensor value of the insulation resistance can be corrected according to the change in the stray capacitance that occurs when each unit connected to the high voltage path 4 is separated by the relay during the operation including the start and stop of the fuel cell vehicle. Insulation resistance detection accuracy is improved.

  The conductivity sensor 10 measures the conductivity of the coolant that cools the fuel cell 2, and the sensor correction unit 14 corrects the sensor value measured by the insulation resistance sensor 5 based on the conductivity value obtained by the conductivity sensor 10. To do. As a result, when the conductivity of the coolant for cooling the fuel cell 2 decreases, the stray capacitance also changes. Therefore, the detection accuracy of the insulation resistance can be improved by correcting the sensor value according to the conductivity of the coolant. .

  The pure water amount calculation unit 15 obtains the amount of pure water generated by the fuel cell 2 during power generation from the generated current of the fuel cell 2, and the sensor correction unit 14 measures the insulation resistance sensor 5 based on the amount of pure water. Correct the sensor value. Thereby, since the sensor value is corrected based on the amount of pure water generated from the fuel cell 2, even when the amount of pure water generated by the fuel cell 2 changes, the detection error of the insulation resistance can be reduced.

  As described above, the present invention has been described according to one embodiment. However, it should not be understood that the description and the drawings, which form a part of this disclosure, limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it should be understood that the present invention includes various embodiments not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

It is a block diagram which shows the structure of the whole fuel cell system containing the insulation resistance measuring system concerning embodiment of this invention. It is a block diagram which shows the structural example of the insulation resistance sensor of FIG. It is a flowchart which shows the measuring method of the insulation resistance by the insulation resistance measurement system of FIG. 4A shows an example of a correction table according to the conductivity of pure water, FIG. 4B shows an example of a correction table according to the output current of the fuel cell, and FIG. 4C shows an insulation resistance. It is a graph which shows the relationship between the sensor value of a sensor, and an insulation resistance value. It is a graph which shows the example of a result of the amplitude value (sensor value) of the waveform which a waveform detector detects when the value of the insulation resistance R and the stray capacitance C in FIG. 3 is changed. FIG. 2 is a block diagram showing a state in which a variable resistor is connected to a high voltage path in the fuel cell system of FIG. 1. It is a graph which shows the preparation method of the table used when performing the correction | amendment according to the electrical conductivity according to the pure water utilized for cooling and humidification with a fuel cell. It is a graph which shows the preparation method of the correction table used when correcting according to the quantity of the pure water which a fuel cell produces | generates at the time of electric power generation. It is a graph for demonstrating the procedure which tabulates the relationship between an insulation resistance value and a sensor value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Fuel cell 3 ... Secondary battery 4 ... High voltage path 5 ... Insulation resistance sensor 6 ... Controller 8 ... Fuel cell side relay 10 ... Conductivity sensor 12 ... Converter 13 ... High voltage auxiliary devices 14 ... Sensor Correction unit 15 ... Pure water amount calculation unit 19 ... Secondary battery side relay 20 ... Compressor 21 ... Compressor side relay 22 ... Low voltage auxiliary machine 23 ... Low voltage battery 24 ... DCDC converter 25 ... Low voltage side relay 26 ... Air conditioner 27 ... Air conditioner Side relay 28 ... circulation path 29 ... circulation pump 30 ... radiator 41 ... variable resistor 301 ... voltage generator 302 ... waveform detector 303 ... insulation resistance 304 ... floating capacitance 305 ... high voltage section 306 ... vehicle body

Claims (3)

An electric motor, a fuel cell that supplies electric power to the electric motor, a secondary battery that charges and discharges electric power between the electric motor and the fuel cell, and the electric motor, the fuel cell, and the secondary battery A high voltage section having at least a high voltage path for electrically connecting
An insulation resistance sensor for measuring an insulation resistance between the high voltage portion and a ground potential;
A blocking unit that blocks the electric motor, the fuel cell, and the secondary battery from the high-voltage path;
An insulation resistance measurement system comprising: a sensor correction unit that corrects a sensor value measured by the insulation resistance sensor according to a connection state of the electric motor, the fuel cell, and the secondary battery. A conductivity sensor for measuring a conductivity of a coolant for cooling the fuel cell;
2. The insulation resistance measurement system according to claim 1, wherein the sensor correction unit corrects a sensor value measured by the insulation resistance sensor based on a conductivity value obtained by the conductivity sensor. A pure water amount calculation unit for obtaining the amount of pure water generated by the fuel cell in power generation from the power generation current of the fuel cell;
The insulation resistance measurement system according to claim 1, wherein the sensor correction unit corrects a sensor value measured by the insulation resistance sensor based on an amount of the pure water.

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