JP2011174895A - Electrical leak detector and electrical leak detection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical leak detector and electrical leak detection unit for certainly, easly and inexpensively detecting electrical leak. <P>SOLUTION: This electrical leak detector is equipped with: a high-voltage power supply system 1 for supplying high voltage; a plurality of components driven by high voltage; a plurality of main coils 11a that are connected to respective components and where electrical leak current flows in respective components; a plurality of electrical leak detecting coils 19 that are disposed in respective main coils and where induced current flows by a magnetic field generated when the electrical leak current flows in the main coils; and a plurality of electrical leak detection circuits 20 for detecting the voltage value of the current flowing in each electrical leak detecting coil, and, when each voltage value is a predetermined threshold or higher, detecting the electrical leak in the components. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a leakage detection device and a leakage detection unit, and more particularly to a leakage detection device and a leakage detection unit for detecting leakage in a component to which a high voltage is supplied.

  Various components such as electric compressors for vehicles applied to hybrid vehicles, fuel cell vehicles, electric vehicles, plug-in hybrid vehicles, etc. are connected to high voltage batteries and power supply circuits (hereinafter referred to as “high voltage power supply circuits”). It is driven by a high voltage power supply circuit. The high-voltage power supply circuit is insulated from the vehicle chassis from the viewpoint of ensuring safety. However, if the insulation between the high-voltage power supply circuit and the vehicle chassis is broken due to some malfunction, a serious accident will occur. May be invited. For this reason, it is necessary to detect insulation lowering or electric leakage of the vehicle system system that controls these components as well as the components connected to the high voltage power supply circuit.

  As a technique for detecting such a leakage, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-57490) is referred to as a so-called coupling capacitor method, and an AC test voltage generation circuit is connected through a coupling capacitor and an impedance element. A leakage detection device is disclosed that outputs an AC test voltage to a high-voltage battery and determines the insulation performance of the high-voltage circuit system from the voltage at the measurement point. Further, in Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-157631), a leakage detector detects that a leakage has occurred in any of the high voltage components connected to the fuel cell. A technique for specifying which of the high-voltage components is leaking by sequentially disconnecting and connecting the relays connected to the high-voltage components by the specifying unit is disclosed.

JP 2007-57490 A JP 2007-157631 A

  However, in the conventional technique described above and the technique disclosed in Patent Document 1, it can be detected that a leakage has occurred in any of the devices connected to the high voltage circuit system. There is a problem that it is impossible to detect whether or not a leakage has occurred. On the other hand, although the technique disclosed in Patent Document 2 can specify which of the high-voltage components has a leakage, the number of components is large, the weight is increased, the cost is high, and all high-voltage components are controlled. There is a problem that the system software becomes complicated.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a leakage detection device and a leakage detection unit capable of reliably detecting a leakage simply and inexpensively.

In order to solve the above problems, the present invention employs the following means.
The present invention includes a high-voltage power source that supplies a high voltage, a plurality of components driven by the high voltage, a plurality of main coils that are connected to the components and in which a leakage current flows in the components, and the main components A plurality of leakage detection coils, each of which is provided in the coil, and an induced current flows due to a magnetic field generated when the leakage current flows through the main coil, and a voltage value of the current flowing in each of the leakage detection coils is detected, Provided is a leakage detection device including a plurality of leakage detection circuits that detect leakage in a component when each voltage value is equal to or greater than a predetermined threshold.

  According to the present invention, when a leakage occurs in each component, a leakage current flows through the main coil, and a magnetic field is generated around the main coil due to the leakage current flowing. An induced current is generated in the leakage detection coil due to the magnetic field generated in the main coil, and a voltage caused by the induced current is generated at both ends of the leakage detection coil. Then, the leakage detection circuit detects the voltage value of this voltage to determine whether or not a leakage has occurred in the component according to the voltage value. A main coil, a leakage detection coil, and a leakage detection circuit for detecting such a leakage are connected to each of the plurality of components, and the plurality of leakage detection circuits detect a leakage in the component. For this reason, it is easy to identify the component in which the leakage has occurred, and it is possible to reliably detect the leakage with a simple and low cost.

  In the above invention, a control circuit for controlling each of the components is provided, and when the leakage detection circuit detects a leakage in any of the components, a leakage detection signal is output to the control circuit, and the control circuit Preferably, the component is controlled based on a leakage detection signal.

  According to the present invention, when a leakage is detected by the leakage detection circuit, a leakage detection signal indicating that the leakage has been detected is output to the control circuit, and the control circuit detects the leakage based on this signal. Control the components. Therefore, by controlling so as to protect the component in which the leakage has occurred, it is possible to limit the malfunction caused by the leakage to the minimum range including the component.

  The present invention also provides a main coil through which a leakage current flows, a leakage detection coil through which an induced current flows due to a magnetic field generated when the leakage current flows through the main coil, and a voltage value of the current flowing through the leakage detection coil. An earth leakage detection unit comprising: an earth leakage detection circuit that detects and detects an earth leakage when the voltage value is equal to or greater than a predetermined threshold value.

  According to the present invention, when a leakage occurs in a device to which the leakage detection unit is applied, a leakage current flows through the main coil, and a magnetic field is generated around the main coil due to the leakage current. An induced current is generated in the leakage detection coil due to the magnetic field generated in the main coil, and a voltage caused by the induced current is generated at both ends of the leakage detection coil. Then, the leakage detection circuit detects the voltage value of this voltage to determine whether or not a leakage has occurred in the device according to the voltage value. For this reason, it is easy to identify the component in which the leakage has occurred, and it is possible to reliably detect the leakage with a simple and low cost.

  As described above, according to the present invention, it is possible to reliably detect a leakage at a simple and low cost.

It is a block diagram showing a schematic structure at the time of applying to a vehicle driven using a ground-fault detection device high voltage power supply concerning one embodiment of the present invention.

Hereinafter, an embodiment of a leakage detection device according to the present invention will be described with reference to the drawings. In the present embodiment, a case where the leakage detection device is applied to a vehicle having a high voltage power source such as an electric vehicle or a hybrid vehicle and a high voltage component driven using the high voltage power source will be described.
FIG. 1 is a block diagram showing a schematic configuration when the leakage detection device according to the present embodiment is applied to a component driven using a high-voltage power supply.

  As shown in FIG. 1, an electric vehicle includes a vehicle high-voltage system 1 including a high-voltage power source that supplies a high voltage to various components constituting the electric vehicle, an inverter-integrated electric compressor 2 (hereinafter simply referred to as “compressor”). 2 ”) and the like, and a plurality of components (not shown) driven by a high voltage supplied by a high voltage power supply of the high voltage system 1, and a leakage current that is connected to each component and detects a leakage of the component. A detection unit 3 is provided. FIG. 1 particularly shows an example in which the leakage detection unit 3 is connected to the compressor 2.

  As described above, the vehicle high-voltage system 1 is connected to various components (not shown) constituting a vehicle having a high-voltage power source such as a compressor 2, a power steering, an electric motor, an air conditioner, and a DCDC converter. High voltage is supplied to

  The compressor 2 includes a common mode coil 11, an inverter 13 including an inverter control circuit 12, a coil 14, a capacitor 15, and a three-phase output motor 16. The common mode coil 11 serves as a high-frequency rejection filter, and includes two coils 11a and 12b connected to the P-pole side and the N-pole side of the vehicle high-voltage system 1, respectively. The inverter control circuit 12 controls the inverter 13, outputs a predetermined control signal to the inverter 13, and responds to a leakage state when leakage of the compressor 2 is detected in the leakage detection circuit 20 described later. Output control signals.

  The inverter 13 converts high voltage DC power supplied from the vehicle high voltage system 1 into AC power in accordance with a control signal from the inverter control circuit 12. The inverter 13 is connected to the three-phase output motor 16. The high-voltage DC power supplied from the vehicle high-voltage system 1 is converted into AC power by the inverter 13 and supplied to the three-phase output motor. Then, the three-phase output motor 16 supplied with AC power is driven and controlled so as to perform a desired operation.

  The leakage detection unit 3 is provided in the vicinity of the coil 11a (main coil). The leakage detection coil 19 in which an induced current flows due to the magnetic field generated when the leakage current flows in the coil 11a, and the current flowing in the leakage detection coil 19 And a leakage detection circuit 20 that detects a leakage of the compressor 2 based on the voltage value. The leakage detection circuit 20 stores a predetermined threshold value for the voltage value. The leakage detection circuit 20 detects a voltage due to the induced current generated in the leakage detection coil 19 and compares the voltage value with the threshold value. When the detected voltage value is equal to or greater than the threshold value, the leakage of the compressor 2 is detected. The leakage detection circuit 20 outputs the detected voltage value together with the leakage detection signal indicating that the leakage has been detected to the inverter control circuit 12 when the leakage is detected.

Hereinafter, the operation of the leakage detection apparatus configured as described above will be described.
Normally, high voltage power from the vehicle high voltage system 1 is supplied to the compressor 2 via an inverter 13 and is driven to rotate by this high voltage power. In a state where no electric leakage occurs, the common mode coil 11 suppresses common mode noise emission from various components. The leakage detection coil 19 detects the voltage value of the induced current due to the magnetic field caused by noise, but the leakage detection circuit 20 does not detect the leakage because the voltage value of the induced current caused by noise does not exceed the threshold value.

  On the other hand, when electric leakage occurs in the compressor 2, that is, when insulation deterioration or breakdown occurs, for example, when a person touches the vehicle high-voltage system in a state where insulation of the inverter 13 or the like of the compressor 2 is lowered. In addition, a leakage current flows through the compressor 2. At this time, a leakage current flows through the coil 11 a of the common mode coil 11 provided in the compressor 2. Since the leakage current flows, a magnetic field is generated in the vicinity of the coil 11a, so that an induced current is generated in the leakage detection coil 19 disposed in the vicinity of the coil 11a.

  The leakage detection circuit 20 detects the voltage value of the induced current generated in the leakage detection coil 19 and compares this voltage value with a threshold value. In the leakage detection circuit 20, when the detected voltage value is equal to or greater than the threshold value as a result of the comparison between the voltage value and the threshold value, it is detected that the leakage has occurred in the compressor 2, and the detected voltage value together with the leakage detection signal is obtained. Output to the inverter control circuit 12.

  In the inverter control circuit 12, the state of leakage is determined from the leakage detection signal and the voltage value, and, for example, the rotational speed of the three-phase output motor 16 is decreased until the leakage current becomes a specified value or less according to the voltage value. Then, a control signal for stopping the compressor 2 itself is output to the inverter 13. The inverter 13 adjusts the power output to the three-phase output motor 16 according to this control signal. As a result, the three-phase output motor 16 reduces its rotation speed or stops its rotation.

  According to the present invention, when a leakage current flows through the common mode coil as the main coil, an induced current is generated in the leakage detection coil due to the magnetic field generated in the vicinity of the common mode coil due to the leakage current, and the induced current is generated at both ends of the leakage detection coil. A voltage resulting from is generated. Then, the leakage detection circuit detects the voltage value of this voltage to determine whether or not a leakage has occurred in the compressor according to the voltage value. Since each coil is a simple and low-priced part, it is possible to reliably detect a leakage at a simple and low cost.

  In addition, when leakage is detected, the inverter control circuit controls to protect itself (compressor) in response to the leakage detection signal from the leakage detection circuit. It can be kept in. Furthermore, since the leakage detection coil and the leakage detection circuit are not directly connected to the vehicle high voltage system and the compressor, the insulation of the vehicle high voltage system does not deteriorate.

  In addition, according to the present invention, there is a low possibility of a decrease in insulation of the vehicle high-voltage system, and even when a leakage occurs in the compressor, the leakage can be accurately detected and the protection operation can be performed. It is also possible to apply an inexpensive PAG oil that is lower in insulation than the POE oil used in the compressor but is widely used as a belt drive compressor.

  In the above-described embodiment, for the sake of convenience of explanation, the configuration in which the leakage detection unit is provided in the compressor as an example of the component has been mainly described. However, the leakage detection is performed for each of the other components connected to the vehicle high voltage system. It is preferable that a unit is provided to detect a leakage in each component. With this configuration, it is possible to easily identify in which component the leakage has occurred as the leakage detection device.

  The inverter control circuit 12 is not limited to the configuration described above, and is configured to further output a leakage detection signal to a higher-order control system such as a control system that controls the vehicle via, for example, CAN (Control Area Network) or local communication. Also good. In this case, the host control system that has received the leakage detection signal has a control signal for stopping driving the compressor 2, a control signal for reducing the rotational speed of the motor 16 of the compressor 2 until the leakage current becomes a specified value or less, and A control signal for stopping the supply of high-voltage power is output, or a control signal for stopping the supply of high-voltage power to the entire vehicle or a control signal for notifying the vehicle crew is appropriately output. be able to.

DESCRIPTION OF SYMBOLS 1 Vehicle high voltage system 2 Inverter integrated electric compressor 3 Leakage detection unit 11 Common mode coils 11a and 11b Coil 12 Inverter control circuit 13 Inverter 16 Three-phase output motor 19 Leakage detection coil 20 Leakage detection circuit

Claims (3)

A high voltage power supply for supplying high voltage;
A plurality of components driven by the high voltage;
A plurality of main coils connected to each of the components, and through which a leakage current flows in the components;
A plurality of leakage detection coils each provided in the main coil, wherein an induced current flows due to a magnetic field generated when the leakage current flows in the main coil;
Detecting a voltage value of a current flowing through each of the leakage detection coils, and detecting a leakage in the component when each voltage value is equal to or greater than a predetermined threshold; and
An earth leakage detection device. A control circuit for controlling each of the components;
When the leakage detection circuit detects a leakage in any of the components, a leakage detection signal is output to the control circuit,
The leakage detection device according to claim 1, wherein the control circuit controls the component based on the leakage detection signal. A main coil through which a leakage current flows;
A leakage detection coil in which an induced current flows due to a magnetic field generated when the leakage current flows in the main coil;
A leakage detection circuit that detects a voltage value of a current flowing through the leakage detection coil and detects a leakage when the voltage value is equal to or greater than a predetermined threshold;
Leakage detection unit equipped with.

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