WO2022080111A1

WO2022080111A1 - Earth leakage determining device

Info

Publication number: WO2022080111A1
Application number: PCT/JP2021/034918
Authority: WO
Inventors: 朝道溝口
Original assignee: 株式会社デンソー
Priority date: 2020-10-12
Filing date: 2021-09-23
Publication date: 2022-04-21
Also published as: JP7468287B2; JP2022063792A; DE112021005379T5

Abstract

An earth leakage determining device (20) for determining the presence or absence of an earth leakage between a direct-current power source (10) and a grounding portion (G1) is provided with: a detection resistance portion (31 to 33) having one end connected to the grounding portion; a first switch (S1) provided between the other end of the detection resistance portion and the positive electrode terminal of the direct-current power source; a second switch (S2) connected between the other end of the detection resistance portion and the negative electrode terminal of the direct-current power source; a charge/discharge element (51, 81, 82, Lx) and a third switch (S3) provided in a charge/discharge path (L3) connecting the grounding portion and the other end of the detection resistance portion; a control portion (40) for switching each switch on and off; and a determining portion (40) for acquiring the voltage of the detection resistance portion and determining the presence or absence of earth leakage on the basis of the acquired voltage of the detection resistance portion. The determining portion acquires the voltage to be used for determining the presence or absence of earth leakage after completion of an on-period of the third switch.

Description

Leakage judgment device

Cross-reference of related applications

This application is based on Japanese Application No. 2020-172213 filed on October 12, 2020, and the contents of the description are incorporated herein by reference.

This disclosure relates to an earth leakage determination device.

Conventionally, an electric leakage determination device for determining the presence or absence of an electric leakage between a DC power supply and a grounding portion has been known.

Patent Document 1 describes an electric leakage determination device that detects the voltage of a detection resistor portion having one end connected to the grounding portion and determines the presence or absence of electric leakage based on the detected voltage. Here, when the capacitance to ground existing between the DC power supply and the grounding portion is large, the time change of the voltage of the detection resistance portion becomes gradual. In this case, in order to detect the voltage of the detection resistor without being affected by the ground capacitance, it is necessary to wait for the ground capacitance to be charged. Therefore, if the charging to the ground capacitance is not completed within the required time, the voltage detection accuracy of the detection resistor portion may deteriorate, and the determination accuracy of the presence or absence of electric leakage may deteriorate.

In order to deal with this problem, there is known a technique of detecting a voltage used for determining the presence or absence of electric leakage after rapidly charging the ground capacitance. For example, Patent Document 2 describes a leakage determination device provided with a plurality of AC power supplies having different peak voltage values as a configuration for rapidly charging the ground capacitance. The AC power supply having the highest peak value among the plurality of AC power supplies rapidly charges the ground capacitance. Further, for example, Patent Document 3 describes an electric leakage determination device provided with a path for rapidly charging the ground capacitance. By reducing the resistance value of the resistor provided in this path, the capacitance to ground is rapidly charged.

Japanese Patent No. 5861954 Japanese Unexamined Patent Publication No. 2020-64042 Japanese Unexamined Patent Publication No. 2020-56732

The number of parts of the earth leakage determination device can be increased by adding a configuration for rapidly charging the ground capacitance. For example, in Patent Document 3, the path for charging the ground capacitance existing between the positive electrode terminal of the DC power supply and the grounded portion and the ground electrostatic capacity existing between the negative electrode terminal of the DC power supply and the grounded portion. Each of the paths for charging the capacitance is provided with a switch for switching between the conduction state and the cutoff state of the resistor. In this case, the number of switches increases, and the number of parts of the leakage determination device increases.

The present disclosure has been made in view of the above problems, and its main purpose is to provide an earth leakage determination device capable of improving the accuracy of determining the presence or absence of an electric leakage while reducing the number of parts.

The present disclosure relates to a detection resistance unit having one end connected to the grounding portion in an electric leakage determination device for determining the presence or absence of electric leakage between the DC power supply and the grounding portion, and the detection resistance portion by turning on. The first switch, which makes a conduction state between the end and the positive terminal of the DC power supply and turns off the other end of the detection resistance portion and the positive voltage terminal of the DC power supply, is turned on. As a result, the other end of the detection resistance portion and the negative voltage terminal of the DC power supply are brought into a conductive state, and by turning off, the other end of the detection resistance portion and the negative voltage terminal of the DC power supply are cut off. A charge / discharge path for connecting the grounding portion and the other end of the detection resistance portion, and a charge / discharge element provided in the charge / discharge path and having an impedance smaller than that of the detection resistance portion. And, it is provided in the charge / discharge path, and when it is turned on, the other end of the detection resistance portion and the grounding portion are made conductive, and when it is turned off, the other end of the detection resistance portion and the grounding portion are connected. A third switch that cuts off the voltage between the two, a control unit that switches on or off the first switch, the second switch, and the third switch, and the second switch that is turned on and the first switch is turned on. The voltage of the detection resistance unit, which is the voltage of the detection resistance unit in the first period in which is turned off, and the voltage of the detection resistance unit in the second period in which the second switch is turned on and the first switch is turned off. The control unit includes a determination unit that acquires the second voltage, and determines the presence or absence of the leakage based on the acquired first voltage and the second voltage, and the control unit is one of the first periods. The third switch is turned on in the unit, the third switch is turned on in a part of the second period, and the determination unit is the third of the first period after the end of the on period of the third switch. One voltage is acquired, and the second voltage after the end of the on period of the third switch in the second period is acquired.

When the capacitance to ground is large, the time change of the first voltage in the first period becomes gradual. In this case, in order to detect the first voltage without being affected by the ground capacitance, it is necessary to wait for the ground capacitance to be charged or discharged. Similarly, when the capacitance to ground is large, the time change of the second voltage in the second period becomes gradual. In this case, in order to detect the second voltage without being affected by the ground capacitance, it is necessary to wait for the ground capacitance to be charged or discharged. Therefore, charging or discharging of the capacitance to ground may not be completed within the required time, the detection accuracy of the first voltage and the second voltage may deteriorate, and the determination accuracy of the presence or absence of electric leakage may deteriorate. ..

Therefore, in the present disclosure, an on period of the third switch is provided prior to the detection of the first voltage in the first period. Further, an on period of the third switch is provided prior to the detection of the second voltage in the second period. During the on period of the third switch, the third switch makes the other end of the detection resistance portion and the grounded portion conductive, and the positive electrode side capacitance existing between the positive electrode terminal of the DC power supply and the grounded portion and the positive electrode side capacitance and the grounded portion. Charging and discharging are performed between the negative electrode side capacitance existing between the negative electrode terminal of the DC power supply and the grounding portion. Here, the impedance of the charging / discharging element is smaller than the resistance value of the detection resistance portion. Therefore, charging or discharging to the ground capacitance can be completed rapidly via the charging / discharging element. As a result, charging or discharging to the ground capacitance can be completed within the required time, the voltage detection accuracy of the detection resistor can be improved, and the determination accuracy of the presence or absence of electric leakage is improved. be able to.

In the present disclosure, the charge / discharge control of the positive electrode side capacitance and the charge / discharge control of the negative electrode side capacitance are performed by a common charge / discharge element and a third switch. Therefore, the number of switches can be reduced as compared with the case where the charge / discharge control of the positive electrode side capacitance and the charge / discharge control of the negative electrode side capacitance are performed by different switches. As a result, the number of parts of the leakage determination device can be reduced.

From the above, according to the present disclosure, it is possible to improve the accuracy of determining the presence or absence of leakage while reducing the number of parts of the leakage determination device.

The above objectives and other objectives, features and advantages of the present disclosure will be further clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a configuration diagram of an electric leakage determination device according to the first embodiment. FIG. 2 is a diagram showing a current path when the first switch is turned on and the second and third switches are turned off. FIG. 3 is a diagram showing a current path when the second switch is turned on and the first and third switches are turned off. FIG. 4 is a diagram showing a current path when the first and third switches are turned on and the second switch is turned off. FIG. 5 is a diagram showing a current path when the second and third switches are turned on and the first switch is turned off. FIG. 6 is a time chart showing changes in the detected voltage and the like when the charge / discharge period is insufficient. FIG. 7 is a time chart showing changes in the detected voltage and the like when the charge / discharge period is excessive. FIG. 8 is a time chart showing changes in the detected voltage and the like when the charge / discharge period is appropriate. FIG. 9 is a correspondence table between the time change amount of the first and second voltages and the first and second charge / discharge periods. FIG. 10 is a flowchart of the process performed by the control device. FIG. 11 is a time chart showing an example of the processing performed by the control device. FIG. 12 is a configuration diagram of an electric leakage determination device according to a comparative example. FIG. 13 is a correspondence table between the time change amount of the first and second voltages and the first and second charge / discharge periods according to the second embodiment. FIG. 14 is a flowchart of the process performed by the control device. FIG. 15 is a time chart showing an example of the processing performed by the control device. FIG. 16 is a block diagram of the leakage determination device according to the third embodiment. FIG. 17 is a configuration diagram of the leakage determination device according to the fourth embodiment. FIG. 18 is a time chart showing changes in the current and voltage of the positive electrode side capacitance and the negative electrode side capacitance. FIG. 19 is a diagram showing a current path when the first and third switches are turned on and the second switch is turned off. FIG. 20 is a diagram showing a current path when the second and third switches are turned on and the first switch is turned off. FIG. 21 is a time chart showing an example of the processing performed by the control device. FIG. 22 is a configuration diagram of the leakage determination device according to the first modification of the fourth embodiment. FIG. 23 is a configuration diagram of the leakage determination device according to the second modification of the fourth embodiment.

<First Embodiment>
Hereinafter, the first embodiment in which the leakage determination device according to the present disclosure is embodied will be described with reference to the drawings. The leakage determination device of the present embodiment is mounted on a control system of an electrified vehicle such as a hybrid vehicle or an electric vehicle, for example.

As shown in FIG. 1, the control system includes a storage battery 10 as a "DC power source" and an electric leakage determination device 20. The positive electrode terminal of the storage battery 10 and the first external terminal P1 of the leakage determination device 20 are connected by a positive electrode side path L1. The negative electrode terminal of the storage battery 10 and the second external terminal P2 of the leakage determination device 20 are connected by a negative electrode side path L2.

The storage battery 10 is an assembled battery in which a plurality of battery cells are connected in series, and the voltage Vc between terminals of the storage battery 10 is, for example, 100 V or more. As the battery cell, for example, a lithium ion storage battery or a nickel hydrogen storage battery can be used. The voltage Vc between the terminals of the storage battery 10 is supplied to a rotary electric machine as an in-vehicle main engine via an inverter. In FIG. 1, the inverter and the rotary electric machine constituting the control system are not shown.

The positive electrode side path L1 is electrically insulated from the grounding portion G1 of the vehicle body or the like. The insulation state between the positive electrode side path L1 and the ground contact portion G1 can be expressed as the positive electrode side ground fault resistance Rp. Further, between the positive electrode side path L1 and the grounding portion G1, there is a capacitor as a passive element for noise reduction and a ground capacitance such as stray capacitance, which are collectively represented as a positive electrode side capacitance Cp.

The negative electrode side path L2 is electrically insulated from the ground contact portion G1 of the vehicle body or the like. The insulation state between the negative electrode side path L2 and the grounding portion G1 can be expressed as the negative electrode side ground fault resistance Rn. Further, between the negative electrode side path L2 and the grounding portion G1, there is a capacitor as a passive element for noise reduction and a ground capacitance such as stray capacitance, which are collectively represented as the negative electrode side capacitance Cn.

In this embodiment, the positive electrode side and negative electrode side capacitances Cp and Cn include, but are not limited to, the capacitance of the capacitor as a passive element in addition to the stray capacitance. For example, in the case of a control system in which a capacitor as a passive element is not provided between the positive electrode side / negative electrode side paths L1 and L2 and the grounding portion G1, the positive electrode side and negative electrode side capacitances Cp and Cn are only stray capacitances. That is, the positive electrode side and negative electrode side capacitances Cp and Cn are composed of at least stray capacitance.

The leakage determination device 20 includes a first switch S1 and a second switch S2. One end of the first switch S1 and one end of the second switch S2 are connected at the connection point M. The other end of the first switch S1 is connected to the first external terminal P1. When the first switch S1 is turned on, the positive electrode terminal of the storage battery 10 and the connection point M are in a conductive state, and when the switch S1 is turned off, the positive electrode terminal of the storage battery 10 and the connection point M are cut off. .. The other end of the second switch S2 is connected to the second external terminal P2. When the second switch S2 is turned on, the negative electrode terminal of the storage battery 10 and the connection point M are in a conductive state, and when the switch S2 is turned off, the negative electrode terminal of the storage battery 10 and the connection point M are cut off. ..

The leakage determination device 20 includes a voltage detection unit 30. The voltage detection unit 30 includes a first resistor 31, a second resistor 32, a third resistor 33, and a constant voltage source 34 with reference to the grounding portion G1. One end of the first resistor 31 is connected to the connection point M. The other end of the first resistor 31 is connected to one end of the second resistor 32. Let N be the connection point between the other end of the first resistor 31 and one end of the second resistor 32. The other end of the second resistor 32 is connected to the grounding portion G1. The constant voltage source 34 is connected to one end of the third resistor 33, and the other end of the third resistor 33 is connected to the connection point N. Note that FIG. 1 shows the output voltage of the constant voltage source 34 in Vdc.

The leakage determination device 20 includes a control device 40. The control device 40 outputs a signal for switching on / off of the first and second switches S1 and S2. A voltage signal corresponding to the voltage of the connection point N is input to the control device 40. The control device 40 has a storage unit that stores various information including the input voltage signal. The storage unit is a non-transitional substantive recording medium other than ROM (for example, a non-volatile memory other than ROM). In the present embodiment, the control device 40 corresponds to the "control unit".

In the first to third resistors 31 to 33, the resistance values R1 to R3 of the resistors 31 to 33 are set in order to step down the voltage signal to a voltage range (for example, 0 to 5 V) that can be input to the control device 40. To. In the present embodiment, the resistance value R1 of the first resistor 31 is larger than the resistance value R2 of the second resistor 32 and the resistance value R3 of the third resistor 33. For example, the resistance value R1 of the first resistor 31 is several MΩ, and the resistance values R2 and R3 of the second and

third resistors

32 and 33 are several kΩ. The control device 40 detects the voltage at the connection point N based on the input voltage signal. In the present embodiment, the first to third resistors 31 to 33 correspond to the "detection resistance section".

The leakage determination device 20 includes a rapid charge / discharge unit 50. The rapid charge / discharge unit 50 has a rapid charge / discharge path L3, a fourth resistor 51, and a third switch S3. The rapid charge / discharge path L3 connects the connection point M and the third external terminal P3 of the leakage determination device 20. The third external terminal P3 is connected to the grounding portion G1. The fourth resistor 51 and the third switch S3 are provided in the rapid charge / discharge path L3. One end of the fourth resistor 51 is connected to the third external terminal P3. The third switch S3 connects the other end of the fourth resistor 51 to the connection point M. The third switch S3 is switched on and off by the control device 40. In the present embodiment, the resistance value R4 of the fourth resistor 51 is, for example, several hundred kΩ, which is smaller than the combined resistance value (R1 + R2) of the first resistor 31 and the second resistor 32. In the present embodiment, the fourth resistor 51 corresponds to the “charge / discharge element”.

Next, the method of calculating the resistance values of the local entanglement resistances Rp and Rn will be described.

FIG. 2 shows a current path when a sufficient time has elapsed after the first switch S1 is turned on and the second and third switches S2 and S3 are turned off. FIG. 3 shows a current path when a sufficient time has elapsed after the second switch S2 is turned on and the first and third switches S1 and S3 are turned off. In the circuits shown in FIGS. 2 and 3, a current path including a positive electrode terminal of the storage battery 10 → a ground fault resistance Rp on the positive electrode side → a ground fault resistance Rn on the negative electrode side → a negative electrode terminal of the storage battery 10 is commonly formed.

In FIG. 2, in addition to the above-mentioned current path, the positive electrode terminal of the storage battery 10 → the first switch S1 → the first resistor 31 → the second resistor 32 → the grounding portion G1 → the negative electrode side ground fault resistance Rn → the negative electrode of the storage battery 10. A current path consisting of terminals is formed. In this case, the positive electrode side ground fault resistance Rp is connected in parallel to the first and

second resistors

31, 32. Therefore, the voltage drop amount of the positive electrode side ground fault resistance Rp is smaller than the voltage drop amount of the negative electrode side ground fault resistance Rn. That is, the voltage applied to the positive electrode side capacitance Cp is lower than the voltage applied to the negative electrode side capacitance Cn. The control device 40 acquires the detection voltage Vr of the voltage detection unit 30 in this state as the first voltage V1 and uses it for calculating the resistance values of the interrelated resistances Rp and Rn.

In FIG. 3, in addition to the above-mentioned current path, the positive electrode terminal of the storage battery 10 → the ground fault resistance Rp on the positive electrode side → the grounding portion G1 → the second resistor 32 → the first resistor 31 → the second switch S2 → the negative electrode of the storage battery 10. A current path consisting of terminals is formed. In this case, the negative electrode side ground fault resistance Rn is connected in parallel to the first and

second resistors

31, 32. Therefore, the voltage drop amount of the negative electrode side ground fault resistance Rn is smaller than the voltage drop amount of the positive electrode side ground fault resistance Rp. That is, the voltage applied to the negative electrode side capacitance Cn is lower than the voltage applied to the positive electrode side capacitance Cp. The control device 40 acquires the detected voltage Vr in this state as the second voltage V2 and uses it for calculating the resistance values of the interfering resistors Rp and Rn. The constant voltage source 34 and the third resistor 33 are provided so that the second voltage V2 can be detected as a non-zero voltage value.

The control device 40 calculates the resistance values of the local resistances Rp and Rn based on the first and second voltages V1 and V2. As a method for calculating the resistance values of the interrelated resistances Rp and Rn, for example, a method according to the method described in Patent Document 1 may be used. In this method, the equations including the resistance value of the ground fault resistance Rp on the positive side and the equation including the resistance value of the ground fault resistance Rn on the negative side are combined to solve the simultaneous equations, and the resistances of the ground faults Rp and Rn in each region are combined. It calculates the value. The presence or absence of electric leakage is determined based on the calculated resistance values of the local resistances Rp and Rn. In the present embodiment, the control device 40 corresponds to the "determination unit".

From the time when the first switch S1 is turned on and the second and third switches S2 and S3 are turned off until the state shown in FIG. 2 is obtained, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is set. It will be charged. In this case, since the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is performed via the first resistor 31 having a large resistance value, it takes time to reach the state shown in FIG.

On the other hand, from the time when the second switch S2 is turned on and the first and third switches S1 and S3 are turned off until the state shown in FIG. 3 is obtained, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance is charged. Cn is discharged. Also in this case, since the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is performed via the first resistor 31 having a large resistance value, it takes time to reach the state shown in FIG. Therefore, charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn may not be completed within the required time, and the detection accuracy of the first and second voltages V1 and V2 may deteriorate. In particular, when the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are large, the detection accuracy of the first and second voltages V1 and V2 may be significantly deteriorated.

Therefore, in the present embodiment, the third switch S3, the fourth resistor 51, and the rapid charge / discharge path L3 are provided as a configuration for rapidly charging / discharging the positive electrode side capacitance Cp and the negative electrode side capacitance Cn.

FIG. 4 shows a current path in the first charge / discharge period Tpp in which the first and third switches S1 and S3 are turned on and the second switch S2 is turned off. The positive electrode side capacitance Cp is discharged by a current path including a first switch S1 → a third switch S3 → a fourth resistor 51 → a positive electrode side capacitance Cp. On the other hand, the negative electrode side capacitance Cn is charged by a current path including a positive electrode terminal of the storage battery 10 → a first switch S1 → a third switch S3 → a fourth resistor 51 → a negative electrode side capacitance Cn → a negative electrode terminal of the storage battery 10. As a result, the voltage applied to the positive electrode side capacitance Cp is lowered, and the voltage applied to the negative electrode side capacitance Cn is increased.

Here, the discharge of the positive electrode side capacitance Cp and the charge of the negative electrode side capacitance Cn are performed via the fourth resistor 51. Since the resistance value R4 of the fourth resistor 51 is smaller than the resistance value R1 of the first resistor 31, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is rapidly charged. As a result, the period until the state shown in FIG. 2 can be obtained can be shortened.

FIG. 5 shows a current path in the second charge / discharge period Tpn in which the second and third switches S2 and S3 are turned on and the first switch S1 is turned off. The negative electrode side capacitance Cn is discharged by a current path including a fourth resistor 51 → a third switch S3 → a second switch S2 → a negative electrode side capacitance Cn. On the other hand, the positive electrode side capacitance Cp is charged by a current path including a positive electrode terminal of the storage battery 10 → a positive electrode side capacitance Cp → a fourth resistor 51 → a third switch S3 → a second switch S2 → a negative electrode terminal of the storage battery 10. As a result, the voltage applied to the positive electrode side capacitance Cp is increased, and the voltage applied to the negative electrode side capacitance Cn is decreased.

Here, the discharge of the negative electrode side capacitance Cn and the charge of the positive electrode side capacitance Cp are also performed via the fourth resistor 51. Therefore, the negative electrode side capacitance Cn is discharged and the positive electrode side capacitance Cp is charged rapidly. As a result, the period until the state shown in FIG. 3 can be obtained can be shortened.

Next, the transition of the detected voltage Vr when each switch S1 to S3 is turned on and off will be described in detail.

FIG. 6 shows the transition of the detected voltage Vr when the first and second charge / discharge periods Tpp and Tpn are insufficient for an appropriate length. In FIG. 6, (a) shows the driving state of the first switch S1, (b) shows the driving state of the second switch S2, (c) shows the driving state of the third switch S3, and (d) shows the driving state of the third switch S3. The transition of the detected voltage Vr and the ideal voltage Vd is shown. In FIG. 6D, the detected voltage Vr is shown by a solid line, and the ideal voltage Vd is shown by a broken line. The ideal voltage Vd is a voltage when the values of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are 0, and is a voltage to be detected as the first voltage V1 and the second voltage V2. In FIG. 6, the first and second charge / discharge periods Tpp and Tpn are set to 0.

At time t1, the first switch S1 is switched on and the second and third switches S2 and S3 are turned off. In this case, since the positive electrode terminal of the storage battery 10 and the connection point M are connected, the detection voltage Vr rises. In the first period T1 from the time t1 to the time t2 when the first switch S1 is switched off, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged. When the voltage applied to the positive electrode side capacitance Cp gradually decreases, the detected voltage Vr gradually decreases. In this case, since the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is mainly performed via the first resistor 31, the gradual decrease rate of the detected voltage Vr is low. Therefore, the first voltage V1 is detected at time t2 before the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is completed. In this case, the first voltage V1 is higher than the ideal voltage Vd, and the detection accuracy of the first voltage V1 deteriorates.

At time t3, the second switch S2 is switched on. In this case, since the negative electrode terminal of the storage battery 10 and the connection point M are connected, the detection voltage Vr drops. In the second period T2 from the time t3 to the time t4 when the second switch S2 is switched off, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged. When the voltage applied to the negative electrode side capacitance Cn gradually decreases, the detected voltage Vr gradually increases. In this case, since the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is mainly performed via the first resistor 31, the gradual increase rate of the detected voltage Vr is low. Therefore, the second voltage V2 is detected at time t4 before the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is completed. In this case, the second voltage V2 is lower than the ideal voltage Vd, and the detection accuracy of the second voltage V2 deteriorates. Not only when the first and second charge / discharge periods Tpp and Tpn are 0, but also when the first and second charge / discharge periods Tpp and Tpn are insufficient for an appropriate length, the first , The detection accuracy of the second voltages V1 and V2 deteriorates.

FIG. 7 is a transition of the detected voltage Vr when the first and second charge / discharge periods Tpp and Tpn are excessive with respect to an appropriate length. 7 (a) to 7 (d) correspond to FIGS. 6 (a) to 6 (d).

At time t1, the first and third switches S1 and S3 are switched on, and the second switch S2 is turned off. From time t1 to time t2 when the third switch S3 is switched off, the current path shown in FIG. 4 is formed, the positive electrode side capacitance Cp is discharged, and the negative electrode side capacitance Cn is charged. In this case, since the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are charged and discharged via the fourth resistor 51, the speed at which the detected voltage Vr gradually decreases is such that charging and discharging are performed via the first resistor 31. Faster than it would be. Therefore, if the first charge / discharge period Tpp, which is the period from time t1 to time t2, is excessively long with respect to an appropriate length, the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are excessively charged / discharged.

At time t2, the detected voltage Vr is lower than the ideal voltage Vd. Therefore, from the time t2 to the time t3 when the first switch S1 is switched off, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged. Therefore, the detected voltage Vr gradually increases. In this case, since the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is mainly performed via the first resistor 31, the speed at which the detected voltage Vr gradually increases is charged via the fourth resistor 51. Slower than when discharging occurs. Therefore, at time t3, the detection voltage Vr remains lower than the ideal voltage Vd, and the detection accuracy of the first voltage V1 deteriorates. In FIG. 7, the time t1 to the time t3 is the first period T1.

At time t4, the second and third switches S2 and S3 are switched on. From time t4 to time t5 when the third switch S3 is switched off, the current path shown in FIG. 5 is formed, the positive electrode side capacitance Cp is charged, and the negative electrode side capacitance Cn is discharged. In this case, since the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are charged and discharged via the fourth resistor 51, the speed at which the detected voltage Vr gradually increases is such that charging and discharging are performed via the first resistor 31. Faster than it would be. Therefore, if the second charge / discharge period Tpn, which is the period from time t4 to time t5, is excessively long with respect to an appropriate length, the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are excessively charged / discharged.

At time t5, the detected voltage Vr is higher than the ideal voltage Vd. Therefore, from the time t5 to the time t6 when the second switch S2 is switched off, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged. Therefore, the detected voltage Vr gradually decreases. In this case, since the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is mainly performed via the first resistor 31, the speed at which the detected voltage Vr gradually decreases is charged via the fourth resistor 51. Slower than when discharging occurs. Therefore, at time t6, the detection voltage Vr remains higher than the ideal voltage Vd, and the detection accuracy of the second voltage V2 deteriorates. In FIG. 7, the time t4 to the time t6 is the second period T2.

FIG. 8 shows the transition of the detected voltage Vr when the first and second charge / discharge periods Tpp and Tpn are set to appropriate lengths. 8 (a) to 8 (d) correspond to FIGS. 6 (a) to 6 (d).

At time t1, the first and third switches S1 and S3 are switched on, and the second switch S2 is turned off. From the time t1 to the time t2 when the first charge / discharge period Tpp has elapsed, the current path shown in FIG. 4 is formed, the positive electrode side capacitance Cp is discharged, and the negative electrode side capacitance Cn is charged. At time t2, the detected voltage Vr coincides with the ideal voltage Vd. Therefore, from the time t2 to the time t3 when the first switch S1 is turned off, the current path shown in FIG. 2 is formed, and the detected voltage Vr becomes constant. Therefore, the control device 40 can accurately detect the first voltage V1 at, for example, at time t3 when the first switch S1 is switched off. In FIG. 8, the time t1 to the time t3 is the first period T1.

At time t4, the second and third switches S2 and S3 are switched on. From the time t4 to the time t5 when the second charge / discharge period Tpn has elapsed, the current path shown in FIG. 5 is formed, the positive electrode side capacitance Cp is charged, and the negative electrode side capacitance Cn is discharged. At time t5, the detected voltage Vr coincides with the ideal voltage Vd. Therefore, from the time t5 to the time t6 when the second switch S2 is switched off, the current path shown in FIG. 3 is formed, and the detected voltage Vr becomes constant. Therefore, the control device 40 can accurately detect the second voltage V2, for example, at time t6. In FIG. 8, the time t4 to the time t6 is the second period T2.

As described in FIGS. 6 and 7, if the first and second charge / discharge periods Tpp and Tpn are not set to appropriate lengths, the detection accuracy of the first and second voltages V1 and V2 may deteriorate. .. Therefore, in the present embodiment, it is assumed that the first and second voltages V1 and V2 are detected at predetermined intervals, and the next cycle is based on the time change amounts dVp and dVn of the first and second voltages V1 and V2. It was decided that the first and second charge / discharge periods Tpp and Tpn in the above were set.

FIG. 9 shows the correspondence between the time change amount dVp of the first voltage V1 and the increase / decrease of the first charge / discharge period Tpp, and shows the time change amount dVn of the second voltage V2 and the increase / decrease of the second charge / discharge period Tpn. The correspondence relationship of is shown.

When the time change amount dVp of the first voltage V1 is a negative value, the first charge / discharge period Tpp in the next cycle is increased. When the time change amount dVp of the first voltage V1 is a positive value, the first charge / discharge period Tpp in the next cycle is shortened. As a result, the first charge / discharge period Tpp in the next cycle is set so as to reduce the time change amount dVp of the first voltage V1. When the time change amount dVp of the first voltage V1 is 0, the first charge / discharge period Tpp in the current cycle is used as the first charge / discharge period Tpp in the next cycle. In the present embodiment, the determination of whether or not the time change amount dVp of the first voltage V1 is 0 determines whether or not the absolute value of the time change amount dVp of the first voltage V1 is smaller than the predetermined value k. It is done by judging.

In the present embodiment, feedback control is performed in which the operation amount is set to the first charge / discharge period Tpp in order to set the time change amount dVp of the first voltage V1 to 0. As the feedback control of the first voltage V1, the proportional integral control shown in the following equation (e1) is used.

The first term on the right side of the above equation (e1) is a proportional term, the second term on the right side is an integral term, and the third term on the right side is the initial value of the first charge / discharge period Tpp or the first charge / discharge in the previous control cycle. The period Tpp. The coefficient KP is a proportional coefficient and the coefficient KI is an integral coefficient.

When the time change amount dVn of the second voltage V2 is a positive value, the second charge / discharge period Tpn in the next cycle is increased. When the time change amount dVn of the second voltage V2 is a negative value, the second charge / discharge period Tpn in the next cycle is shortened. As a result, the second charge / discharge period Tpn in the next cycle is set so as to reduce the time change amount dVn of the second voltage V2. When the time change amount dVn of the second voltage V2 is 0, the second charge / discharge period Tpn in the current cycle is used as the second charge / discharge period Tpn in the next cycle. In the present embodiment, the determination of whether or not the time change amount dVn of the second voltage V2 is 0 determines whether or not the absolute value of the time change amount dVn of the second voltage V2 is smaller than the predetermined value k. It is done by judging.

In the present embodiment, feedback control is performed in which the operation amount is set to the second charge / discharge period Tpn in order to set the time change amount dVn of the second voltage V2 to 0. As the feedback control of the second voltage V2, the proportional integral control shown in the following equation (e2) is used.

The first term on the right side of the above equation (e2) is a proportional term, the second term on the right side is an integral term, and the third term on the right side is the initial value of the second charge / discharge period Tpn or the second charge / discharge in the previous control cycle. The period Tpn. The feedback control of the first and second voltages V1 and V2 is not limited to the proportional integral control, and may be, for example, the proportional integral differential control.

FIG. 10 shows a procedure of processing performed by the control device 40. This process is performed when the start condition is met. The start condition is set arbitrarily.

In step S100, the initial values of the first and second charge / discharge periods Tpp and Tpn are set. In the present embodiment, the first charge / discharge period Tpp = 0 and the second charge / discharge period Tpn = 0 are set as initial values.

In step S101, the first switch S1 is switched on. As a result, the first period T1 is started. In step S102, the third switch S3 is switched on. As a result, the first charge / discharge period Tpp is started. In step S103, after the third switch S3 is turned on, the process waits for the first charge / discharge period Tpp. During this standby period, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged by the current path shown in FIG. In step S104, the third switch S3 is turned off. This ends the first charge / discharge period Tpp.

In step S105, the first voltage V1 immediately after the third switch S3 is turned off is detected, and the detected value is stored in the storage unit as V1a. The process of step S105 is performed at a timing slightly delayed from the off timing of the third switch S3. As a result, it is possible to suppress the noise generated when the third switch S3 is switched off from being mixed in the detection voltage Vr. In step S106, after the third switch S3 is turned off, the process waits only for a period excluding the first charge / discharge period Tpp from the first period T1. In step S107, the first voltage V1 after standby is detected and stored in the storage unit as V1b. In step S108, the first switch S1 is turned off. As a result, the first period T1 is terminated. The process of step S107 is performed at a timing slightly earlier than the off timing of the first switch S1. As a result, it is possible to suppress the noise generated when the first switch S1 is switched off from being mixed in the detection voltage Vr. In step S109, the patient waits for a predetermined third period T3.

In step S110, the second switch S2 is turned on. As a result, the second period T2 is started. In step S111, the third switch S3 is turned on. As a result, the second charge / discharge period Tpn is started. In step S112, after the third switch S3 is turned on, the process waits for the second charge / discharge period Tpn. During this standby period, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged by the current path shown in FIG. In step S113, the third switch S3 is turned off. As a result, the second charge / discharge period Tpn is terminated.

In step S114, the second voltage V2 immediately after the third switch S3 is turned off is detected and stored in the storage unit as V2a. The process of step S114 is performed at a timing slightly delayed from the off timing of the third switch S3. As a result, it is possible to suppress the noise generated when the third switch S3 is switched off from being mixed in the detection voltage Vr. In step S115, the standby is performed only for a period excluding the second charge / discharge period Tpn from the second period T2. In step S116, the second voltage V2 after standby is detected and stored in the storage unit as V2b. In step S117, the second switch S2 is turned off. As a result, the second period T2 is terminated. The process of step S116 is performed at a timing slightly earlier than the off timing of the second switch S2. As a result, it is possible to suppress the noise generated when the second switch S2 is switched off from being mixed in the detection voltage Vr.

In step S118, the time change amount dVp of the first voltage V1 and the time change amount dVn of the second voltage V2 are calculated. The time change amount dVp of the first voltage V1 is obtained by the following equation (e3).

Here, V1a is the detection voltage stored in the storage unit in step S105, V1b is the detection voltage stored in the storage unit in step S107, and Δt1 is the first standby time. In the present embodiment, the first standby time Δt1 is a period shorter than the period obtained by removing the first charge / discharge period Tpp from the first period T1. This is because the processing of step S105 is slightly delayed from the off timing of the third switch S3, and the processing of step S107 is slightly earlier than the off timing of the first switch S1.

The time change amount dVn of the second voltage V2 is obtained by the following equation (e4).

Here, V2a is the detection voltage stored in the storage unit in step S114, V1b is the detection voltage stored in the storage unit in step S116, and Δt2 is the second standby time. In the present embodiment, the second standby time Δt2 is a period shorter than the period obtained by removing the second charge / discharge period Tpn from the second period T2. This is because the processing of step S114 is slightly delayed from the off timing of the third switch S3, and the processing of step S116 is slightly earlier than the off timing of the second switch S2.

In step S119, the first and second charge / discharge periods Tpp and Tpn in the next control cycle are calculated by performing feedback control of the first and second voltages V1 and V2.

In step S120, the absolute value of the calculated time change amount dVp of the first voltage V1 is smaller than the predetermined value k, and the absolute value of the calculated time change amount dVn of the second voltage V2 is larger than the predetermined value k. Determine if it is small.

If a negative determination is made in step S120, it is determined that the first and second charge / discharge periods Tpp and Tpn are not appropriate lengths, and the process proceeds to step S122. In step S122, only the third period T3 is awaited.

If an affirmative determination is made in step S120, it is determined that the first and second charge / discharge periods Tpp and Tpn have appropriate lengths, and the process proceeds to step S121. In step S121, the resistance values of the local entanglement resistors Rp and Rn are calculated based on the first and second voltages V1b and V2b detected in this cycle. Then, the process proceeds to step S122.

In step S123, it is determined whether or not the stop condition of this process is satisfied. The stop condition can be set arbitrarily. If a negative determination is made in step S123, the process returns to step S101, and this process is repeatedly performed using the updated first and second charge / discharge periods Tpp and Tpn. On the other hand, if an affirmative determination is made in step S123, this process ends.

FIG. 11 shows an example of the control performed by the control device 40. In FIG. 11, (a) shows the driving state of the first switch S1, (b) shows the driving state of the second switch S2, (c) shows the driving state of the third switch S3, and (d) shows the driving state of the third switch S3. The transition of the detected voltage Vr and the ideal voltage Vd is shown. In FIG. 11D, the detected voltage Vr is shown by a solid line, and the ideal voltage Vd is shown by a broken line. FIG. 11 shows the transition of the on / off and the detection voltage Vr of the first to third switches S1 to S3 over four cycles.

In the first cycle Ts1, the time change amount dVp of the first voltage V1 is set to a negative value, and the time change amount dVn of the second voltage V2 is set to a positive value. This state is the same as the state described with reference to FIG. 6, and the charge / discharge of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is insufficient. Therefore, the feedback control in step S119 updates the first and second charge / discharge periods Tpp and Tpn so that the first and second charge / discharge periods Tpp and Tpn in the second cycle Ts2 increase.

In the second cycle Ts2, the time change amount dVp of the first voltage V1 is made smaller than the time change amount dVp of the first voltage V1 in the first cycle Ts1, and the time change amount dVp of the second voltage V2 is the first cycle. It is made smaller than the time change amount dVp of the second voltage V2 in Ts1. However, since the time change amount dVp of the first voltage V1 is set to a negative value and the time change amount dVp of the second voltage V2 is set to a positive value, the feedback control in step S119 again causes the third cycle Ts3. The first and second charge / discharge periods Tpp and Tpn are updated so that the first and second charge / discharge periods Tpp and Tpn increase.

In the third cycle Ts3, the time change amount dVp of the first voltage V1 is set to 0, and the time change amount dVp of the second voltage V2 is set to 0. This state is the same as the state described with reference to FIG. 8, and the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is completed. Therefore, in the 4th cycle Ts4, the 1st and 2nd charge / discharge periods Tpp and Tpn in the 3rd cycle Ts3 are used. The calculation of the resistance values of the interrelated resistances Rp and Rn is carried out in the third cycle Ts3 and the fourth cycle Ts4.

FIG. 12 describes a case where the circuit unit 60 of the comparative example is provided in the leakage determination device 20 instead of the rapid charge / discharge unit 50 of the present embodiment. In FIG. 12, the configurations shown in FIG. 1 above are designated by the same reference numerals for convenience.

The circuit unit 60 includes a fourth resistor 51, a fourth switch S4, and a fifth switch S5. One end of the fourth resistor 51 is connected to the third external terminal P3. The other end of the fourth resistor 51 is connected to the intermediate point A of the fourth switch S4 and the fifth switch S5. The fourth switch S4 connects the intermediate point A and between the first external terminal P1 and the first switch S1. The fifth switch S5 connects the intermediate point A and between the second external terminal P2 and the second switch S2.

When the 4th switch S4 is turned on and the 5th switch S5 is turned off, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged. Further, when the fifth switch S5 is turned on and the fourth switch S4 is turned off, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged. However, in this case, two switches are required to charge and discharge the positive electrode side capacitance Cp and the negative electrode side capacitance Cn. As a result, in the comparative example, the number of parts of the leakage determination device 20 increases.

According to the present embodiment described in detail above, the following effects can be obtained.

Prior to the detection of the first voltage V1, the first charge / discharge period Tpp is provided. In the first charge / discharge period Tpp, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged via the fourth resistor 51. On the other hand, a second charge / discharge period Tpn is provided prior to the detection of the second voltage V2. In the second charge / discharge period Tpn, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged via the fourth resistor 51. As a result, charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is completed earlier than in the case of charging / discharging the positive electrode side capacitance Cp and the negative electrode side capacitance Cn via the first and

second resistors

31 and 32. be able to. Therefore, an appropriate first voltage V1 can be detected in the first period T1, and an appropriate second voltage V2 can be detected in the second period T2. As a result, the detection accuracy of the first voltage V1 and the second voltage V2 can be improved, and by extension, the determination accuracy of the presence or absence of electric leakage can be improved.

Charging / discharging of the positive electrode side capacitance Cp and charging / discharging of the negative electrode side capacitance Cn are performed by the common fourth resistor 51 and the third switch S3. Therefore, the number of switches can be reduced as compared with the case where the charge / discharge of the positive electrode side capacitance Cp and the charge / discharge of the negative electrode side capacitance Cn are controlled by different switches. As a result, the number of parts of the leakage determination device 20 can be reduced.

Feedback control is carried out with the operation amount as the first charge / discharge period Tpp and the time change amount dVp of the first voltage V1 as 0. Further, feedback control is performed in which the operation amount is set to the second charge / discharge period Tpn and the time change amount dVn of the second voltage V2 is 0. As a result, even if the positive electrode side capacitance Cp and the negative electrode side capacitance Cn change and the time required for charging / discharging to the positive electrode side capacitance Cp and the negative electrode side capacitance Cn changes, the first and first are appropriate in response to the changes. 2 Charge / discharge periods Tpp and Tpn are set. As a result, the detection accuracy of the first and second voltages V1 and V2 can be improved.

The first charge / discharge period Tpp is set based on the time change amount dVp of the first voltage V1, and the second charge / discharge period Tpn is set based on the time change amount dVn of the second voltage V2. As a result, the number of parts of the leakage determination device 20 can be reduced as compared with the configuration in which parts for setting the first and second charge / discharge periods Tpp and Tpn are newly added.

From the above, according to the present embodiment, it is possible to improve the accuracy of determining the presence or absence of electric leakage while reducing the number of parts of the electric leakage determination device 20.

<Second Embodiment>
Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the method of setting the first and second charge / discharge periods Tpp and Tpn is changed.

The control device 40 repeatedly turns the third switch S3 on and off during the first charge / discharge period Tpp. Of the first charge / discharge period Tpp, each on period of the third switch S3 is the first minute period Tp. The first minute period Tp is a sufficiently short period as compared with the period required for the discharge of the positive electrode side capacitance Cp to be completed and the charging of the negative electrode side capacitance Cn to be completed. Therefore, in the period until the discharge of the positive electrode side capacitance Cp and the charge of the negative electrode side capacitance Cn are completed, the discharge amount of the positive electrode side capacitance Cp and the charge amount of the negative electrode side capacitance Cn are in a state of being insufficient. Further, of the first charge / discharge period Tpp, the off period of the third switch S3 sandwiched between the first minute period Tp adjacent in time is set as the minute standby period Tw.

The control device 40 repeatedly turns the third switch S3 on and off during the second charge / discharge period Tpn. Of the second charge / discharge period Tpn, each on period of the third switch S3 is the second minute period Tn. The second minute period Tn is a sufficiently short period as compared with the period required for the charging of the positive electrode side capacitance Cp to be completed and the discharge of the negative electrode side capacitance Cn to be completed. Therefore, in the period until the charging of the positive electrode side capacitance Cp and the discharging of the negative electrode side capacitance Cn are completed, the charging amount of the positive electrode side capacitance Cp and the discharging amount of the negative electrode side capacitance Cn are considered to be insufficient. Further, of the second charge / discharge period Tpn, the off period of the third switch S3 sandwiched between the second minute period Tn adjacent in time is set as the minute standby period Tw.

FIG. 13 shows the correspondence between the time change amount dVp of the first voltage V1 and the continuation or stop of the first charge / discharge period Tpp, and shows the time change amount dVn of the second voltage V2 and the second charge / discharge period Tpn. Shows the correspondence with continuation or suspension. When the time change amount dVp of the first voltage V1 is a positive value, the first charge / discharge period Tpp is continued, and when the time change amount dVp of the first voltage V1 is 0, the first charge / discharge period Tpp is stopped. Will be done. When the time change amount dVn of the second voltage V2 is a positive value, the second charge / discharge period Tpn is continued, and when the time change amount dVn of the second voltage V2 is 0, the second charge / discharge period Tpn is stopped. Will be done.

FIG. 14 shows a procedure of processing performed by the control device 40. This process may be carried out at a predetermined cycle, or may be carried out when the conditions for starting the process are satisfied. The start condition may be set arbitrarily.

In step S200, the value of the first counter i is set to 1, and the value of the second counter j is set to 1. The first counter i is used to calculate the duration of the first charge / discharge period Tpp, and the second counter j is used to calculate the duration of the second charge / discharge period Tpn.

In step S201, the first switch S1 is turned on. As a result, the first period T1 is started. In step S202, the third switch S3 is turned on. In step S203, the patient waits for the first minute period Tp. In step S204, the third switch S3 is turned off. In step S205, the first voltage V1 immediately after the third switch S3 is turned off is detected and stored in the storage unit as V1α. In step S206, only the minute waiting period Tw is waited. In step S207, the first voltage V1 after standby is detected and stored in the storage unit as V1β.

In step S208, the time change amount dVp of the first voltage V1 is calculated. The time change amount dVp of the first voltage V1 is obtained by the following equation (e5).

Here, V1α is the detection voltage stored in the storage unit in step S205, and V1β is the detection voltage stored in the storage unit in step S207. In the above equation (e5), the time change amount dVp of the first voltage V1 is set to a positive value.

In step S209, it is determined whether or not the time change amount dVp of the first voltage V1 is smaller than the predetermined value k. If a negative determination is made in step S209, the process proceeds to step S210. In step S210, the value of the first counter i is incremented. Then, the process returns to step S202. As a result, the first charge / discharge period Tpp is continued. On the other hand, if an affirmative determination is made in step S209, the process proceeds to step S211. As a result, the first charge / discharge period Tpp is stopped. In the present embodiment, the first charge / discharge period Tpp is a period from the first step S202 to a positive determination in step S209.

In step S211, only the first residual period is waited. The first residual period is the period obtained by excluding the first charge / discharge period Tpp from the first period T1. In the present embodiment, the first charge / discharge period Tpp is i × (Tp + Tw), and the first residual period is T1-i × (Tp + Tw).

In step S212, the first voltage V1 is detected and stored in the storage unit. In step S213, the first switch S1 is turned off. As a result, the first period T1 is terminated.

In step S214, only the third period T3 is waited. In step S215, the second switch S2 is turned on. As a result, the second period T2 is started. In step S216, the third switch S3 is turned on. In step S217, the patient waits for a second minute period Tn. In step S218, the third switch S3 is turned off. In step S219, the second voltage V2 immediately after the third switch S3 is turned off is detected and stored in the storage unit as V2α. In step S220, only the minute waiting period Tw is waited. In step S221, the second voltage V2 after standby is detected and stored in the storage unit as V2β.

In step S222, the time change amount dVn of the second voltage V2 is calculated. The time change amount dVn of the second voltage V2 is obtained by the following equation (e6).

Here, V2α is the detection voltage stored in the storage unit in step S219, and V2β is the detection voltage stored in the storage unit in step S221.

In step S223, it is determined whether or not the time change amount dVn of the second voltage V2 is smaller than the predetermined value k. If a negative determination is made in step S223, the process proceeds to step S224. In step S224, the value of the second counter j is incremented. After that, the process returns to step S216. As a result, the second charge / discharge period Tpn is continued. On the other hand, if an affirmative determination is made in step S223, the process proceeds to step S225. As a result, the second charge / discharge period Tpn is stopped. In the present embodiment, the second charge / discharge period Tpn is a period from the first step S216 to a positive determination in step S223.

In step S225, wait only for the second residual period. The second residual period is the period obtained by removing the second charge / discharge period Tpn from the second period T2. In the present embodiment, the second charge / discharge period Tpn is j × (Tn + Tw), and the second residual period is T2-j × (Tn + Tw).

In step S226, the second voltage V2 is detected and stored in the storage unit. In step S227, the second switch S2 is turned off. As a result, the second period T2 is terminated.

In step S228, the resistance values of the interrelated resistances Rp and Rn are calculated based on the first voltage V1 stored in the storage unit in step S212 and the second voltage V2 stored in the storage unit in step S226. In step S229, the process waits only for the third period T3 and ends this process.

FIG. 15 shows an example of the control performed by the control device 40. In FIG. 15, (a) shows the driving state of the first switch S1, (b) shows the driving state of the second switch S2, (c) shows the driving state of the third switch S3, and (d) shows the driving state of the third switch S3. The transition of the detected voltage Vr and the ideal voltage Vd is shown. In FIG. 15D, the detected voltage Vr is shown by a solid line, and the ideal voltage Vd is shown by a broken line.

In the example shown in FIG. 15, the third switch S3 is turned on and off six times in the first period T1. In the period from the first turn to the fifth turn of the third switch S3, the calculated time change amount dVp1 to dVp5 of the first voltage V1 is a positive value. Therefore, the on / off of the third switch S3 is continued, and the first charge / discharge period Tpp is continued. In the period when the number of on / off times of the third switch S3 is the sixth time, the calculated time change amount dVp6 of the first voltage V1 is 0. Therefore, the third switch S3 is turned off, and the first charge / discharge period Tpp is stopped. In this case, since the discharge of the positive electrode side capacitance Cp and the charge of the negative electrode side capacitance Cn are completed, the subsequent detection voltage Vr becomes constant. Therefore, after only the first residual period has elapsed, an appropriate first voltage V1 is detected.

In the example shown in FIG. 15, the on / off of the third switch S3 is repeated 6 times even in the second period T2. In the period from the first to the fifth on / off frequency of the third switch S3, the calculated time change amounts dVn1 to dVn5 of the second voltage V2 are positive values. Therefore, the on / off of the third switch S3 is continued, and the second charge / discharge period Tpn is continued. In the period when the number of on / off times of the third switch S3 is the sixth time, the calculated time change amount dVn6 of the second voltage V2 is 0. Therefore, the third switch S3 is turned off, and the second charge / discharge period Tpn is stopped. In this case, since the charging of the positive electrode side capacitance Cp and the discharging of the negative electrode side capacitance Cn are completed, the subsequent detection voltage Vr becomes constant. Therefore, an appropriate second voltage V2 is detected after only the second residual period has elapsed.

In this embodiment, in addition to the same effects as in the first embodiment, the following effects can be obtained.

In the first period T1, the first charge / discharge period Tpp is continued until the time change amount dVp of the first voltage V1 becomes 0. As a result, during the first period T1, the discharge of the positive electrode side capacitance Cp and the charge of the negative electrode side capacitance Cn are completed, and an appropriate first voltage V1 is detected. Further, in the second period T2, the second charge / discharge period Tpn is continued until the time change amount dVn of the second voltage V2 becomes 0. As a result, during the second period T2, the charging of the positive electrode side capacitance Cp and the discharging of the negative electrode side capacitance Cn are completed, and an appropriate second voltage V2 is detected. As a result, the time required for the appropriate first and second voltages V1 and V2 to be detected can be shortened.

<Third Embodiment>
Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In the present embodiment, instead of using the time change amounts dVp and dVn of the first and second voltages V1 and V2 for setting the first and second charge / discharge periods Tpp and Tpn, the rapid charge / discharge path L3 is used. The flowing current is used.

FIG. 16 shows the configuration of the leakage determination device 20 according to the present embodiment. In FIG. 16, the configurations shown in FIG. 1 above are designated by the same reference numerals for convenience.

The leakage determination device 20 includes a current sensor 71, an amplifier 72, and a filter 73. The current sensor 71 is provided between the fourth resistor 51 and the third switch S3 in the rapid charge / discharge path L3. The current sensor 71 can detect a current in a non-contact manner with the rapid charge / discharge path L3, such as a current sensor including a Hall element. A voltage is supplied to the current sensor 71 from the constant voltage source 34 via the amplifier 72. The voltage detected by the current sensor 71 is input to the control device 40 via the filter 73. The control device 40 detects the current flowing in the rapid charge / discharge path L3 based on the input voltage.

The control device 40 sets the first and second charge / discharge periods Tpp and Tpn suitable for completing the charge / discharge of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn based on the detected current Ir of the current sensor 71.

In this embodiment, the first and second charge / discharge periods Tpp and Tpn are set based on the detected current Ir. As a result, the first and second charge / discharge periods Tpp and Tpn suitable for completing the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn are set. Therefore, an appropriate first voltage V1 can be detected in the first period T1, and an appropriate second voltage V2 can be detected in the second period T2. As a result, the detection accuracy of the first voltage V1 and the second voltage V2 can be improved.

Also in this embodiment, the charging / discharging of the positive electrode side capacitance Cp and the charging / discharging of the negative electrode side capacitance Cn are performed by the common fourth resistor and the third switch S3, so that the leakage determination device is similar to the first embodiment. The number of 20 switches can be reduced.

From the above, according to the present embodiment, it is possible to improve the detection accuracy of the first and second voltages V1 and V2 while reducing the number of parts of the leakage determination device 20.

<Fourth Embodiment>
Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the configuration of the leakage determination device 20 is changed.

As shown in FIG. 17, the leakage determination device 20 includes a DCDC converter 80. In the present embodiment, the DCDC converter 80 is a non-isolated converter. In FIG. 17, the configurations shown in FIG. 1 above are designated by the same reference numerals for convenience. The DCDC converter 80 includes a first diode D1 and a second diode D2. The first diode D1 is connected in parallel to the first switch S1, the anode is connected to the connection point M, and the cathode is connected to the first external terminal P1. The second diode D2 is connected in parallel to the second switch S2, the anode is connected to the second external terminal P2, and the cathode is connected to the connection point M.

The DCDC converter 80 includes a reactor Lx instead of the fourth resistor 51. Here, the impedance of the reactor Lx is smaller than the combined impedance of the first resistor 31 and the second resistor 32. In the present embodiment, the reactor Lx corresponds to the "charge / discharge element".

The DCDC converter 80 includes a current sensor 71. The current sensor 71 is provided between the third switch S3 and the connection point M in the rapid charge / discharge path L3. In the present embodiment, the current sensor 71 can detect the current flowing in the rapid charge / discharge path L3 in a non-contact manner, and the detected current Ir of the current sensor 71 is input to the control device 40. The sign of the detection current Ir is positive when it flows from the third switch S3 toward the reactor Lx.

FIG. 18 is a diagram showing changes in the current and voltage of the ground capacitance when the electric charge is charged to the ground capacitance. In FIG. 18, (a) shows the transition of the energization current I flowing through the ground capacitance, and (b) shows the transition of the voltage V of the ground capacitance. In FIGS. 18A and 18B, the transition of the current-carrying current Icr and the voltage Vcr of the ground capacitance in the first embodiment is shown by a solid line, and the current-carrying current Icl and the voltage between terminals of the ground capacitance in the present embodiment are shown. The transition of Vcl is shown by a broken line.

In the configuration according to the first embodiment, the energization current Icr is set to the maximum value Imax immediately after the start of charging the ground capacitance, but is gradually reduced thereafter. Therefore, the ascending speed of the voltage Vcr gradually decreases. In this case, the time required to complete the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn becomes long.

Therefore, in the present embodiment, the DCDC converter 80 is provided as a configuration for maintaining the energization current Icl at a constant value. As a result, the time required for the voltage Vcl to reach the target voltage V * can be shortened.

Next, the control of the DCDC converter 80 will be described.

The control device 40 turns on / off the first switch S1, turns off the second switch S2, and turns on the third switch S3 in order to control the detected current Ir to a positive target current in the first charge / discharge period Tpp. Further, in the second charge / discharge period Tpn, the control device 40 turns off the first switch S1, turns the second switch S2 on and off, and turns on the third switch S3 in order to control the detected current Ir to a negative target current. do.

FIG. 19 shows the current paths I1 and I2 formed when the first and third switches S1 and S3 are turned on and the second switch S2 is turned off. The first current path I1 is a current path including the positive electrode side capacitance Cp → the first switch S1 → the third switch S3 → the reactor Lx. The second current path I2 is a current path including the negative electrode side capacitance Cn → the second diode D2 → the third switch S3 → the reactor Lx. As a result, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged.

FIG. 20 shows the current paths I3 and I4 formed when the second and third switches S2 and S3 are turned on and the first switch S1 is turned off. The third current path I3 is a current path including the positive electrode side capacitance Cp → the reactor Lx → the third switch S3 → the first diode D1. The fourth current path I4 is a current path including the negative electrode side capacitance Cn → reactor Lx → third switch S3 → second switch S2. As a result, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged.

FIG. 21 shows an example of the control performed by the control device 40. In FIG. 21, (a) shows the driving state of the first switch S1, (b) shows the driving state of the second switch S2, (c) shows the driving state of the third switch S3, and (d) shows the driving state of the third switch S3. The transition of the detected current Ir is shown, and (e) shows the transition of the detected voltage Vr and the ideal voltage Vd. In FIG. 21 (e), the transition of the detected voltage Vr is shown by a solid line, and the transition of the ideal voltage Vd is shown by a alternate long and short dash line.

In the first charge / discharge period Tpp, the first switch S1 is turned on / off, the second switch S2 is turned off, and the third switch S3 is turned on. During the period in which the first switch S1 is turned on in the first charge / discharge period Tpp, the current paths I1 and I2 shown in FIG. 19 are formed, the positive electrode side capacitance Cp is discharged, and the negative electrode side capacitance Cn is charged. .. As a result, the detected current Ir is controlled to a positive target value. As a result, the duration of the first charge / discharge period Tpp can be shortened. The duration of the first charge / discharge period Tpp may be set, for example, according to the target value of the detected current Ir in the first period T1.

In the second charge / discharge period Tpn, the first switch S1 is turned off, the second switch S2 is turned on and off, and the third switch S3 is turned on. During the period in which the second switch S2 is turned on in the second charge / discharge period Tpn, the current paths I3 and I4 shown in FIG. 20 are formed, the positive electrode side capacitance Cp is charged, and the negative electrode side capacitance Cn is discharged. .. As a result, the detected current Ir is controlled to a negative target value. As a result, the duration of the second charge / discharge period Tpn can be shortened. The duration of the second charge / discharge period Tpn may be set, for example, according to the target value of the detected current Ir in the second period T2.

In this embodiment, the detected current Ir is maintained at the target value. As a result, the current flowing through the positive electrode side capacitance Cp and the negative electrode side capacitance Cn is also maintained at a constant value. As a result, the time required to complete the charging / discharging of the positive electrode side capacitance Cp and the negative electrode side capacitance Cn can be shortened.

<Modification 1 of the fourth embodiment>
The current sensor 71 is not limited to the one capable of detecting the current without contacting the rapid charge / discharge path L3, and may have a shunt resistor directly attached to the rapid charge / discharge path L3. FIG. 22 shows an example of a configuration including a shunt resistor.

As shown in FIG. 22, the leakage determination device 20 includes a shunt resistor Rs and a differential amplifier circuit 90. One end of the shunt resistor Rs is connected to the third external terminal P3, and the other end is connected to the reactor Lx. The differential amplifier circuit 90 includes an operational amplifier 91, resistors 92 to 95, and a constant voltage source 96. The output voltage of the differential amplifier circuit 90 is input to the control device 40. The control device 40 sets a reference voltage based on the direction of the current flowing through the shunt resistance Rs so that the input voltage from the differential amplifier circuit 90 falls within the voltage range (for example, 0 to 5V) that can be input to the control device 40. The input voltage from the differential amplifier circuit 90 is detected by setting and setting the set reference voltage to 0V. Note that FIG. 22 shows the output voltage of the constant voltage source 96 in Vdc2.

<Modification 2 of the fourth embodiment>
The DCDC converter 80 is not limited to the non-isolated converter, and may be an isolated converter. As shown in FIG. 23, the DCDC converter 80 includes sixth and seventh switches S6 and S7, third and fourth diodes D3 and D4, and a transformer 81. The transformer 81 has a first coil 82 and a second coil 83. The impedances of the first and

second coils

82 and 83 are smaller than the combined impedance of the first resistor 31 and the second resistor 32. In this embodiment, the first and

second coils

82 and 83 correspond to "charge / discharge elements".

The first end of the first coil 82 is connected between the first external terminal P1 and the first switch S1. The second end of the first coil 82 is connected to one end of the sixth switch S6. The other end of the sixth switch S6 is connected to the third external terminal P3. The third diode D3 is connected in parallel to the sixth switch S6, the anode is connected to the third external terminal P3, and the cathode is connected to the second end of the first coil 82.

The first end of the second coil 83 is connected to the third external terminal P3. The second end of the second coil 83 is connected to one end of the seventh switch S7. The other end of the seventh switch S7 is connected between the second external terminal P2 and the second switch S2. The fourth diode D4 is connected in parallel to the seventh switch S7, the anode is connected between the second external terminal P2 and the second switch S2, and the cathode is connected to the second end of the second coil 83. ing.

The first coil 82 and the second coil 83 are magnetically coupled to each other, for example, via a core included in the transformer 81. When the potential of the second end with respect to the first end of the first coil 82 becomes high, an induced voltage is generated in the second coil 83 so that the potential of the first end becomes higher than that of the second end. On the other hand, when the potential of the first end with respect to the second end of the first coil 82 is high, an induced voltage is generated in the second coil 83 so that the potential of the second end is higher than that of the first end.

The control device 40 controls the sixth switch S6 on and off during the first charge / discharge period Tpp. As a result, the positive electrode side capacitance Cp is discharged and the negative electrode side capacitance Cn is charged. On the other hand, the control device 40 controls the seventh switch S7 on and off during the second charge / discharge period Tpn. As a result, the positive electrode side capacitance Cp is charged and the negative electrode side capacitance Cn is discharged. By controlling the on / off ratio in one switching cycle of the sixth and seventh switches S6 and S7, the detection current Ir can be maintained at a constant value.

<Other embodiments>
In addition, each of the above-mentioned embodiments may be changed and carried out as follows.

-In the first embodiment, in step S100, the initial values of the first and second charge / discharge periods Tpp and Tpn are set to 0, but the present invention is not limited to this. When the resistance values of the normal local entanglement resistors Rp and Rn are known, the first and second voltages V1 and V2 can be predicted. Further, when the capacitance of the positive electrode side capacitance Cp and the capacitance of the negative electrode side capacitance Cn are known, the time constant with the fourth resistor 51 can also be calculated. Therefore, the first and second charge / discharge periods Tpp and Tpn may be calculated based on these parameters and used as initial values. In this case, the period until the appropriate first and second charge / discharge periods Tpp and Tpn are set can be shortened.

In the first embodiment, the process of step S105 in FIG. 10 may be performed at the timing of switching off of the third switch S3, and the process of step S107 may be performed at the timing of switching off of the first switch S1. .. In this case, the first standby time Δt1 used in step S118 may be a period obtained by removing the first charge / discharge period Tpp from the first period T1.

-In the first embodiment, the process of step S114 may be performed at the timing of switching off of the third switch S3, and the process of step S116 may be performed at the timing of switching off of the second switch S2. In this case, the second standby time Δt2 used in step S118 may be a period obtained by removing the second charge / discharge period Tpn from the second period T2.

In the second embodiment, the same predetermined value k is used in the process of step S209 and the process of step S223, but the present invention is not limited to this. In step S209, it is determined whether or not the time change amount dVp of the first voltage V1 is smaller than the first predetermined value k1, and the time change amount dVn of the second voltage V2 is a second predetermined value different from the first predetermined value k1. It may be determined whether or not it is smaller than k2.

-The storage battery 10 is not limited to the assembled battery, but may be a single battery.

The controls and methods thereof described in the present disclosure are provided by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may be realized. Alternatively, the controls and methods thereof described in the present disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. It may be realized by one or more dedicated computers configured. Further, the computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by the computer.

Although the present disclosure has been described in accordance with the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various variations and variations within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are within the scope and scope of the present disclosure.

Claims

In the leakage determination device (20) for determining the presence or absence of leakage between the DC power supply (10) and the grounding portion (G1).
A detection resistor portion (31 to 33) having one end connected to the grounding portion,
By turning it on, the other end of the detection resistance portion and the positive electrode terminal of the DC power supply are made conductive, and by turning it off, the other end of the detection resistance portion and the positive electrode terminal of the DC power supply are connected. The first switch (S1) to shut off and
By turning it on, the other end of the detection resistance portion and the negative electrode terminal of the DC power supply are made conductive, and by turning it off, the other end of the detection resistance portion and the negative electrode terminal of the DC power supply are connected. The second switch (S2) to shut off and
A charge / discharge path (L3) connecting the grounding portion and the other end of the detection resistance portion,
Charge / discharge elements (51, 81, 82, Lx) provided in the charge / discharge path and having an impedance smaller than that of the detection resistance portion, and
It is provided in the charge / discharge path, and when it is turned on, the other end of the detection resistance portion and the grounding portion are brought into a conductive state, and when it is turned off, the other end of the detection resistance portion and the grounding portion are connected to each other. The third switch (S3) that shuts off the space,
A control unit (40) for switching on or off of the first switch, the second switch, and the third switch.
The first voltage, which is the voltage of the detection resistor portion in the first period when the first switch is turned on and the second switch is turned off, and the first switch is turned off when the second switch is turned on. A determination unit (40) that acquires a second voltage, which is the voltage of the detection resistance unit in the second period, and determines the presence or absence of the electric leakage based on the acquired first voltage and the second voltage. And with
The control unit turns on the third switch in a part of the first period, and turns on the third switch in a part of the second period.
The determination unit acquires the first voltage after the end of the on period of the third switch in the first period, and the second of the second period after the end of the on period of the third switch. An earth leakage determination device that acquires voltage.
The determination unit acquires the first voltage and the second voltage in each control cycle, and obtains the first voltage and the second voltage in each control cycle.
The control unit
The said amount included in the first period in the next control cycle so that the time change amount of the first voltage in the next control cycle is smaller than the time change amount of the first voltage acquired in the current control cycle. Set the on period of the 3rd switch,
The said is included in the second period in the next control cycle so that the time change amount of the second voltage in the next control cycle is smaller than the time change amount of the second voltage acquired in the current control cycle. The leakage determination device according to claim 1, wherein the on period of the third switch is set.
The control unit
The on / off of the third switch is repeated in the first period, the time change amount of the first voltage in the period in which the third switch is turned off in the first period is calculated, and the calculated time of the first voltage is calculated. When the amount of change is equal to or less than the first predetermined value, the third switch is turned off.
The on / off of the third switch is repeated in the second period, the time change amount of the second voltage in the period in which the third switch is turned off in the second period is calculated, and the time change of the second voltage is calculated. The leakage determination device according to claim 1, wherein the third switch is turned off when the amount is equal to or less than the second predetermined value.
The charge / discharge element is a reactor (Lx) and has a reactor (Lx).
Due to the switching control of the first switch and the second switch, the positive electrode side capacitance existing between the positive electrode terminal of the DC power supply and the grounded portion, and the negative electrode side capacitance of the DC power supply exists between the negative electrode terminal and the grounded portion. A DCDC converter (80) that transfers power to and from the negative electrode side capacitance is provided.
The leakage determination device according to any one of claims 1 to 3, wherein the control unit controls the input / output current of the DCDC converter during the on period of the third switch.
The control unit
During the on period of the third switch in the first period, the switching control of the first switch is performed in order to discharge from the positive electrode side capacitance to the negative electrode side capacitance, and then the third switch is turned off.
In the second period, during the on period of the third switch, the switching control of the second switch is performed in order to discharge from the negative electrode side capacitance to the positive electrode side capacitance, and then the third switch is turned off. The leakage determination device according to claim 4, wherein the entry output current is controlled.