JP2003223841A - Ground-fault detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To locate the leakage point of the system of a drive system under operation. <P>SOLUTION: A leakage detection circuit 22 is provided near a battery 12 of the drive system 10. An electronic control unit 30 for determining the leakage point is provided. The unit 30 can communicate with the drive system control unit 18 that controls the whole system. The unit 30 determines the leakage point, by receiving a leakage signal from the leakage detection circuit 22, the on-off signal of the relay 14 from the driving system control unit 18, and the input of the cut-off signal of inverters INV1 and INV2. For example, it is determined that the leakage is generated between the inverter circuit INV1 and a motor MG1, when the condition of no leakage generation is detected, and while the relay 14 is on, the inverter circuit INV1 is on, and the inverter circuit INV2 is cut-off, and the relay 14 is on and the inverter circuits INV1 and INV2 are cut-off, after the condition of leakage generation is detected. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leakage detection device, and more specifically, to a power supply, a power conversion means capable of converting the power from the power supply into AC power by switching a switching element and supplying the AC power to a load, and the power supply. Leakage detection device for detecting a leakage of a drive system having a relay provided between the power conversion means and the power conversion means to disconnect the power line from the power source, and a control means for driving and controlling the load based on a required output. Regarding

[0002]

2. Description of the Related Art Conventionally, as this type of leakage detection device,
A device that specifies the leakage point of the system according to the operation of the ignition key of the automobile (for example, Japanese Patent Laid-Open No. 7-2743).
No. 03, etc.) and one that specifies a leakage point of a system of an in-vehicle device using a service tool prior to running inspection of an automobile (for example, Japanese Patent Laid-Open No. 10-149493).

[0003]

However, in such an earth leakage detecting device, since the time of earth leakage detection is limited, it may not be possible to specify the earth leakage location with respect to the earth leakage occurring during the operation of the system. .

An object of the leakage detecting device of the present invention is to detect the occurrence of the leakage during the operation of the drive system and to identify the leakage location. Another object of the leakage detection device of the present invention is to more accurately identify the leakage location during operation of the drive system.

[0005]

Means for Solving the Problems and Their Actions / Effects The earth leakage detection device of the present invention employs the following means in order to achieve at least a part of the above-mentioned object.

The earth leakage detection device of the present invention includes a power supply, and power conversion means capable of converting the power from the power supply into desired power by switching the switching element and supplying the power to the load.
Drive having a relay provided between the power supply and the power conversion means for connecting and disconnecting a power line from the power supply, and a control means for driving and controlling at least the power conversion means and the relay based on a drive command A leakage detection device for detecting the occurrence of leakage of the system, provided between the power supply and the relay, leakage detection means for detecting the leakage of the drive system, the said according to the drive control by the control means The gist of the present invention is to include an operating state detecting unit that detects an operating state of the drive system, and an electric leakage point determining unit that determines an electric leakage point based on the detection results of the electric leakage detecting unit and the operating state detecting unit.

In this leakage detection device of the present invention, the leakage detection means provided between the power source of the drive system and the relay detects the leakage of the drive system, and the operation state detection means is controlled by the control means of the drive system. The operating state of the drive system according to the drive control is detected. Then, the leakage point determining means determines the leakage point based on the detection results of the leakage detecting means and the operating state detecting means. Therefore, by monitoring the leakage detection by the leakage detection unit and the operating state of the drive system according to the control by the control unit, the location of the leakage even during operation of the drive system, for example, between the power supply and the relay, the relay and the power It is possible to determine where the leakage is occurring between the conversion means and between the power conversion means and the load. Here, the "operation of the drive system" includes at least the operation of the relay and the operation of the switching element of the power conversion means.

In the leakage detecting device of the present invention,
The leakage location determining means may be means for determining the leakage location based on a plurality of types of detection results by the leakage detecting means and the operating state detecting means. By doing so, it is possible to more accurately identify the leakage point from the plurality of types of detection results.

Further, in the leakage detection device of the present invention, the leakage location determining means controls the drive system to perform a predetermined operation for identifying the leakage location when the leakage location is not identified for a predetermined time. It may be a means for instructing the means and determining the leakage location based on the detection result of the leakage detecting means in the operating state of the drive system based on the instruction.

Further, in the earth leakage detection device of the present invention, the load includes an electric motor which is rotationally driven by a polyphase alternating current,
The power conversion means may include an inverter circuit capable of converting the power from the power source into multi-phase AC power by switching the switching element and supplying the multi-phase AC power to the electric motor.

Further, in the earth leakage detection device of the present invention, the control means sequentially gives connection switching signals to the relay and the power conversion means, and the earth leakage point judging means based on the detection result at this time. It is preferable to determine the leakage point. As a result, it is possible to quickly identify the leakage point within a short time.

Here, based on the change in the detection result by the leakage detecting means before and after the control means gives the connection switching signal to the relay or the power converting means, the leakage location determining means causes the connection switching signal to change. It is preferable to determine whether or not there is a leakage point on the downstream side of the relay or the electric power conversion means to which the above is given. That is, it is possible to determine that there is a leakage point on the downstream side when the detection result changes, and to determine that there is no leakage point on the downstream side when the detection result does not change.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described using examples. FIG. 1 shows the motors MG1 and M.
It is a block diagram which shows the outline of a structure at the time of applying the earth leakage detection apparatus 20 which is the 1st Example of this invention to the drive system 10 which drives G2. For convenience of description, the drive system 10 will be described first, and then the leakage detection device 2 of the embodiment.
0 will be described. The drive system 10 is output from a battery 12 capable of inputting / outputting DC power, an inverter circuit INV1 that converts the DC power from the battery 12 into three-phase AC power by switching of a switching element and outputs the three-phase AC power, and an inverter circuit INV1. A motor MG1 that receives and rotates three-phase AC, and an inverter circuit INV1
Inverter circuit INV2 configured to share positive electrode bus 16 and negative electrode bus 17 and converting DC power from battery 12 into three-phase AC power by switching of switching elements and outputting the three-phase AC power, and inverter circuit INV2 A motor MG2 that receives a phase alternating current to rotate and drive, a relay 14 that is provided between the battery 12 and the inverter circuits INV1 and INV2 to connect and disconnect the power line from the battery 12, and a required power from the motors MG1 and MG2. And a drive system control unit 18 for controlling the entire system so as to output. The inverter circuits INV1 and INV2 are composed of six switching elements, and are arranged in pairs such that the positive side bus 16 and the negative side bus 17 are on the source side and the sink side, and the motor MG1 is located at the connection point. , MG2 of each phase (U, V, W) is connected. Motor MG
1 and MG2 are configured as, for example, a synchronous generator motor capable of generating power, which includes a rotor having a permanent magnet attached to the outer surface thereof and a stator having a three-phase coil wound thereon.
Although not shown, the drive system control unit 18 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port. Prepare The drive system control unit 18 outputs an ON / OFF signal to the relay 14 and a switching control signal for controlling switching of the switching elements to the inverter circuits INV1 and INV2 through the output port. The leakage detection device 20 of the embodiment is a device that detects the leakage of the drive system 10 and identifies the leakage location.

As shown in the figure, the leakage detecting device 20 of the embodiment is provided between the battery 12 and the relay 14 to detect the leakage of the drive system 10, and the state of the relay 14 and the inverter circuit INV1. , An electronic control unit 30 that determines a leakage point from the state of INV2,
A monitor 40 as a display device is provided. Although the electronic control unit 30 is provided separately from the drive system control unit 18 described above, the drive system control unit 18 may also be configured to serve as the electronic control unit 30. As the leakage detection circuit 22, for example, various known circuits disclosed in Japanese Patent Laid-Open No. 8-70503 can be used. Therefore, detailed description of the leakage detection circuit 22 will be omitted.

The electronic control unit 30 is configured as a microprocessor centered on a CPU 32, and has a ROM 34 for storing a processing program, a RAM 36 for temporarily storing data, and an input / output port (not shown).
And a communication port (not shown). The electronic control unit 30 can communicate with the drive system control unit 18 described above through a communication port. In addition, a leakage detection signal from the leakage detection circuit 22 or the like is input to the electronic control unit 30 via the input port, and the electronic control unit 30 monitors the monitor 4 or the like.
A display signal for 0 and the like are output through the output port.

The operation of the earth leakage detection device 20 of the embodiment thus constructed, particularly the operation of determining the earth leakage location when the earth leakage is detected will be described. FIG. 2 is a flowchart showing an example of a leakage point determination processing routine executed by the electronic control unit 30 of the leakage detection device 20 of the embodiment. This routine is executed when a leakage detection signal indicating occurrence of leakage is input from the leakage detection circuit 22.

When the leakage point determination processing routine is executed, the CPU 32 of the electronic control unit 30 first causes the drive system control unit 18 via the communication port.
From the operating state of the drive system 10 and the leakage detection circuit 2
The information regarding the presence / absence of electric leakage from 2 is read (step S100), and the processing for determining the location of the electric leakage is performed from the read operating state and the information regarding the presence / absence of electric leakage (step S102). The operating state of the drive system 10 includes the on / off state of the relay 14 and the inverter circuits INV1 and INV1.
This is an ON / OFF state of the NV2 switching element (a state of whether all six switching elements are OFF (shutdown state)). Hereinafter, the process of determining the leakage location will be described.

In the drive system 10, the process for determining the leakage point is performed by the power supply line from the battery 12 to the relay 14 and from the relay 14 to the inverter circuits INV1 and INV.
DC line up to V2, first AC line from inverter circuit INV1 to motor MG1, inverter circuit IN
This is a process of determining in which part of the second AC line from V2 to the motor MG2 the leakage has occurred. For example, in the first routine, when the occurrence of leakage is detected by the leakage detection circuit 22 and the off state of the relay 14 is detected, the electric power from the battery 12 is supplied to the relay 1
Since it is cut off by No. 4, it can be determined that the above-mentioned power leak has occurred in the power supply line. Further, when the occurrence of leakage is detected and the ON state of the relay 14 and the shutdown state of both the inverter circuits INV1 and INV2 are detected, the power from the battery 12 is cut off by the inverter circuits INV1 and INV2. ,
It can be determined that a leak has occurred in any of the above-mentioned power supply line or DC line. Further, when the occurrence of leakage is detected and the ON state of the relay 14 and the drive state of one of the inverter circuits INV1 and INV2 and the shutdown state of the other are detected, the above-mentioned power supply line or DC line, the first or first It can be determined that leakage has occurred in any of the two AC lines corresponding to the driving inverter circuit. Further, when the occurrence of leakage is detected and the ON state of the relay 14 and the driving state of both inverter circuits INV1 and INV2 are detected, the power supply line or the DC line, the first and second lines are detected.
It can be determined that a leak has occurred in one of the AC lines. In this way, the leakage point is determined based on the operating state of the drive system 10 when the leakage is detected. However, depending on the operating state of the drive system 10 as described above, it may not be possible to specify one leakage point, and in this case, the processing from step S108 described below is executed.

As a result of the leakage point determination processing, it is determined whether or not the leakage point is identified as one location (step S104),
When it is determined that the leakage point has been specified in one place,
The identified leakage point is output to the monitor 40 (step S106), and this routine ends. For example, when the occurrence of the electric leakage is detected and the OFF state of the relay 14 is detected, the power supply line can be identified as the electric leakage point, and thus the electric leakage point is output to the monitor 40. On the other hand, when it is not possible to identify the leakage point as one, step S10
The determination information of the leakage point determination process of 2 is stored (step S108). That is, there are a plurality of places where there is a possibility of leakage (for example, leakage occurs in any of the power supply line and the DC line, the power supply line and the DC line and the first AC line, the power supply line, the DC line and the second AC line). Information). Then, it is determined whether or not a predetermined time has elapsed since the execution of this routine was started (step S
110), if it is determined that the time has not elapsed, then the flow returns to the process of step S100. Thereby, step S10
The process of 0 is executed again. For example, step S108
When the information that the electric leakage occurs in either the power supply line or the DC line is stored in, the step S is performed again.
When the occurrence of the electric leakage of the drive system 10 is not detected in the processing of 100 and the OFF state of the relay 14 is read as information, it is determined that the electric leakage is occurring in the DC line in the electric leakage point determination processing of step S102. it can. In step S108, the power line, the DC line and the first
When the information that the leakage is occurring in any of the AC lines is stored, the occurrence of the leakage of the drive system 10 is not detected again in the process of step S100, and the relay 1 is detected.
4 ON state and inverter circuits INV1, INV2
When the shutdown state is detected, it can be determined that the first AC line is leaking. Therefore, at this time, it is determined that the leakage point is identified in step S104, and this leakage point is output to the monitor 40 in step S106. Thus, even when the leakage point is not specified in the first routine, the leakage points are narrowed down by finally repeating the processes of steps S100 to S108, and the leakage point is finally specified.

When it is determined in step S110 that the predetermined time has elapsed, the mode is shifted to the test mode (step S112), and a predetermined operation command is output to the drive system control unit 18 of the drive system 10 (step S114). . The predetermined operation command is a process of instructing the operation of the drive system 10 for specifying the leakage point when the leakage point cannot be specified despite the elapse of the predetermined time. For example, when the above-described predetermined time has elapsed in a state in which the information indicating that the power source line, the DC line, or the first AC line is leaking is stored as the determination information in step S108, the process proceeds to step S114. As the drive command, for example, the electronic control unit 30 outputs a command to turn on the relay 14 and shut down both the inverter circuits INV1 and INV2 to the drive system control unit 18, and at this time, the non-occurrence of electric leakage is detected ( When the occurrence of electric leakage is not detected), it can be specified that electric leakage has occurred in the first AC line. Further, even when the leakage is detected, it is possible to determine that the leakage has occurred in any of the power supply line and the DC line, that is, exclude the first AC line from the leakage point determination target. When the leakage point is specified in this way (step S104), the leakage point is output to the monitor 40 (step S106), and this routine ends. The operation command to the drive system control unit 18 of the drive system 10 is preferably issued within a range that does not affect the normal drive of the drive system 10. Therefore, the command that affects the normal drive of the drive system 10 is issued. It is also possible to terminate this routine without performing any other operation command or as another operation command or as it is without specifying the leakage location.

According to the leakage detecting device 20 of the embodiment described above, by monitoring the state of leakage by the leakage detecting circuit 22 and the operating state of the drive system 10, the leakage points are narrowed down and the final leakage is detected. Since the location is determined,
While the drive system 10 is in operation, it is possible to detect a leakage and specify the leakage location. Therefore, the leakage of the drive system 10 can be detected earlier and the location of the leakage can be specified, so that the safety of the system can be further improved. Moreover, no special operation command is issued to the drive system control unit 18 of the drive system 10 until a predetermined time elapses after the process of determining the leakage point is started, so that the drive system 10 is normally driven. It is possible to identify the leakage point without affecting. Further, when a predetermined time has elapsed since the process of determining the leakage point was started, the operation of the drive system 10 is controlled to identify the leakage point,
Since the leakage location is specified from the leakage state by the leakage detection circuit 22 at this time, the leakage location can be determined more accurately.

In the earth leakage detection device 20 of the embodiment, the operation of the drive system 10 is controlled in order to identify the earth leakage point when a predetermined time has elapsed since the process of determining the earth leakage point was started. It doesn't matter if you don't. This will not affect the normal drive of the drive system 10 when executing the process of identifying the leakage point.

In the leakage detection device 20 of the embodiment, the DC power output from the battery 12 via the relay 14 is switched to the three-phase AC power suitable for driving the motors MG1, MG2 by switching the switching elements of the inverter circuits INV1, INV2. It is applied to the electric leakage detection in the system which is converted into the motor and is supplied to the motors MG1 and MG2.
The present invention may be applied to leakage detection in a system in which electric power supplied from a battery via a relay is converted into desired electric power by switching of a switching element of a power converter and supplied to electric equipment (load). Also,
The number of loads may be one or two or more.

Next, a second embodiment of the present invention will be described. FIG. 3 shows a power supply system 50 including a drive system.
FIG. 7 is a configuration diagram showing a schematic configuration in the case where the leakage detection device 60 according to the second embodiment is applied to FIG. This power supply system 5
0 is mounted on the vehicle and constitutes a part of the vehicle. For convenience of description, the power supply system 50 will be described first, and then
The leakage detection device 60 of the embodiment will be described.

The power supply system 50 has an inverter I for converting the direct current supplied from the battery 52 into an alternating current.
A drive system including NV1 and INV2 and motors MG1 and MG2 driven by the alternating current, DC-DC converters CON1 and CON2 that convert the direct current from the battery 52 into a predetermined direct current, and the direct current A DC supply system including electric devices D1 and D2 supplied with current, relays 54 and 56 of each system, inverters INV1 and INV2, and a converter CON1.
A system control unit 58 for providing a connection switching signal for turning ON / OFF the connection to CON2 is included.

The drive system has substantially the same structure as that of the first embodiment. A relay 54 is connected to a conductive wire extending from the battery 52, and the conductive wire extending from the relay 54 is further provided with an inverter INV which is a power conversion means.
1, INV2 and motors MG1 and MG2 are connected. The battery 52, the relay 54, and the inverter I
Although the connection lines of NV1 and INV2 are shown as a single line for simplification, they are actually two lines as in the first embodiment.

Further, the DC supply system includes a battery 52.
The relay 56 is connected to the conductive wire extending from
DC-DC converters CON1 and CON2, which are power conversion means, are further connected to the conductive wire extending from the relay 56. The converters CON1 and CON2 are connected to the electric devices D1 and D2, and supply a direct current to the electric devices D1 and D2. Here, the electric devices are various devices that operate by receiving the supply of the DC voltage. The converters CON1 and CON2 are composed of a plurality of switching elements and the like, and when all the switching elements are turned off, the battery 52 and the electric devices D1 and D2 are disconnected from each other to enter a shutdown state.

Next, the leakage detection device 60 of this embodiment will be described. The leakage detection device 60 is connected between the battery 52 and the relays 54 and 56, and detects the leakage of the power supply system 50, the state of the relays 54 and 56, the inverters INV1 and INV2, and the converter CO.
The monitor 80 includes an electronic control unit 70 that determines a leakage point from the states of N1 and CON2. The leakage detection circuit 62 detects the peak value, and when the detected peak value is small, the insulation resistance is large. Therefore, when this state continues for a predetermined time (generally about 30 seconds), the leakage is detected. It is to be noted that the predetermined time is required until the detection because the detected peak value may be momentarily reduced due to the influence of other devices mounted on the vehicle.

The earth leakage detection device 60 performs the processing described below. First, the system control unit 58
Provides an OFF signal for turning off the connection to the relays 54, 56, and an OFF signal for shutting down the inverters INV1, INV2 and the converters CON1, CON2.

Next, the relays 54 and 56 and the inverter IN
An ON signal and an OFF signal are sequentially applied to V1 and INV2 and converters CON1 and CON2 one by one. Explaining the drive system as an example, first, an ON signal is given to the upstream relay 54 to bring it into an ON state. Then, in this state, an ON signal is given to the inverter INV1 on the downstream side of the relay 54, and an OFF signal is given to the inverter INV1 after a predetermined time. Inverter I
Similarly, an ON signal and an OFF signal are applied to NV2.
Next, an ON signal is given to the relay 54 located upstream of the inverters INV1 and INV2, and an OFF signal is given after a predetermined time. Similarly, for the DC supply system, the ON signal and the OFF signal are sequentially supplied from the switches or converters CON1 and CON2 on the downstream side.

The electronic control unit 70 is an ON signal or an OFF signal when the system control unit 58 gives the ON signals and the OFF signals to the relays 54, 56 and the power conversion means INV1, INV2, CON1, CON2 in the above-described procedure. The leakage detection circuit 62 detects a change in the detected peak value before and after applying a signal, and performs a process of identifying a leakage point based on the change in the detected peak value. This processing will be described below.

FIG. 4 shows an example of changes in the detected peak value detected by the electronic control unit 70. In the example of FIG. 4A, the detected peak value changes only when the relay 54 is turned on and off. In this case, it is determined that there is a leakage point on the downstream side of the relay 54 where the detection result changes. Further, it is determined that there is no leakage point on the downstream side of the inverters INV1 and INV2 where the detection result does not change and on the DC supply system. Therefore, the relay 54 and each inverter I
It is determined that there is a leakage point on the conductive wire connecting NV1 and INV2.

In the example of FIG. 4B, the inverter I
Only when the NV2 is turned on / off, the detected peak value changes. In this case, the inverter IN whose detection result changes
It is determined that there is a leakage point on the downstream side of V2. Further, between the relay 54 and each of the inverters INV1 and INV2, the downstream side of the inverter INV1 where the detection result does not change,
And it is determined that the DC supply system has no leakage points. The leakage point is specified by the processing described above.

In the present embodiment described above, the relay 5
4, 56, power conversion means INV1, INV2, CON
An ON signal and an OFF signal are sequentially given to 1 and CON2 one by one, and the leakage point is determined based on the detection result by the leakage detection circuit 62 at that time, so that the leakage point can be quickly detected within a short time. There is an effect that can be specified. Therefore, the processing of the present embodiment is performed in a short time period such as a time period from when the key is inserted into the vehicle to start and the motor is driven, or a time period after the motor is stopped and the vehicle is completely stopped. You can also do

At this time, based on the change in the detection result by the leakage detection circuit 62 before and after the system control unit 58 outputs the connection switching signal,
The presence / absence of leakage points on the downstream side is determined. Since the information about the change in the detection result can be acquired only by the time until the detected peak value changes, it is possible to more quickly determine the leakage point.

In this embodiment, all the relays 5
4, 56 and power conversion means INV1, INV2, CON
1, CON2, the change in the detected peak value is stored, and the leakage point is identified from the stored information. However, in another embodiment, the relays 54, 56 when the detected peak value changes or Power conversion means INV1, INV
It is also possible to store only 2, CON1 and CON2 and identify the leakage point from that information.

Although the embodiments of the present invention have been described with reference to the embodiments, the present invention is not limited to the embodiments of the present invention, and various embodiments are possible without departing from the gist of the present invention. Of course, it can be implemented in.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a configuration when a leakage detection device 20 of a first embodiment of the present invention is applied to a drive system 10 that drives motors MG1 and MG2.

FIG. 2 is a flowchart showing an example of a leakage point determination processing routine executed by the electronic control unit 30 of the leakage detection device 20 of the embodiment.

FIG. 3 is a configuration diagram showing an outline of a configuration when an electric leakage detection device 60 of a second embodiment is applied to a power supply system 50.

FIG. 4 is an explanatory diagram showing an example of changes in a detected peak value detected by an electronic control unit 70.

[Explanation of symbols]

10 drive system, 12 battery, 14 relay,
16 positive bus, 17 negative bus, 18 drive system control unit, 20 leakage detection device, 22 leakage detection circuit, 30 electronic control unit, 32 CPU, 3
4 ROM, 36 RAM, 40 monitor, INV1,
INV2 inverter circuit, MG1, MG2 motor.

Continued front page    F-term (reference) 5G004 AA02 AA04 AB02 BA01 CA01                       DC14                 5G030 XX15 YY12

Claims (8)

[Claims] 1. A power supply, power conversion means capable of converting power from the power supply into desired power by switching of a switching element and supplying the power to a load, and the power conversion means provided between the power supply and the power conversion means. A leakage detection device for detecting the occurrence of leakage of a drive system, comprising: a relay that disconnects a power line from a power source; and a control unit that controls drive of at least the power conversion unit and the relay based on a drive command. Provided between the power source and the relay, a leakage detection unit for detecting a leakage of the drive system, an operation state detection unit for detecting an operation state of the drive system according to drive control by the control unit, An electric leakage detection device, comprising: an electric leakage point determining unit that determines an electric leakage point based on detection results of the electric leakage detecting unit and the operation state detecting unit. 2. The leakage detection device according to claim 1, wherein the leakage location determination means determines the leakage location based on a plurality of types of detection results by the leakage detection means and the operation state detection means. Leakage detection device. 3. The earth leakage detection device according to claim 1, wherein the earth leakage location determination means performs a predetermined operation for identifying the earth leakage location when the earth leakage location is not identified for a predetermined time. To the control means of the drive system, and the electric leakage detection device is means for determining the electric leakage point based on the detection result of the electric leakage detection means in the operating state of the drive system based on the instruction. 4. The leakage detection device according to claim 1, wherein the load includes an electric motor that is rotationally driven by a multi-phase alternating current, and the power conversion unit is switched from the power source by switching a switching element. Leakage detection device including an inverter circuit capable of converting the electric power of the above into multi-phase AC power and supplying the same to the electric motor. 5. The leakage detection device according to claim 1, wherein the control unit sequentially supplies a connection switching signal to the relay and the power conversion unit, and the leakage location determination unit An electric leakage detection device characterized by determining an electric leakage point based on a detection result at the time. 6. The earth leakage detection device according to claim 1, wherein the earth leakage detection means is provided before and after the control means gives the connection switching signal to the relay or the power conversion means. The leakage detection device, wherein the leakage point determination means determines the presence or absence of a leakage point on the downstream side of the relay or the power conversion means to which a connection switching signal is given, based on a change in the detection result. 7. The leakage detection device according to claim 6, wherein when the detection result by the leakage detection means changes, the leakage location determination means is caused by the relay or the power conversion means to which the connection switching signal is given. An electric leakage detection device characterized by determining that there is an electric leakage point on the downstream side. 8. The leakage detection device according to claim 6, wherein when the detection result by the leakage detection means does not change, the leakage location determination means is the relay or the power conversion means to which the switching signal is given. An electric leakage detection device characterized by determining that there is no electric leakage point on the downstream side.