CN111094074A

CN111094074A - Interlocking device for high-voltage equipment

Info

Publication number: CN111094074A
Application number: CN201880059656.7A
Authority: CN
Inventors: 吉田浩
Original assignee: Sanden Automotive Conponents Corp
Current assignee: Sanden Corp
Priority date: 2017-09-14
Filing date: 2018-08-13
Publication date: 2020-05-01
Anticipated expiration: 2038-08-13
Also published as: DE112018005169T5; JP6889642B2; CN111094074B; JP2019051790A; WO2019054128A1

Abstract

The invention provides an interlock device for high-voltage equipment, which can accurately detect the disconnection of a connector to be in an unsafe state (disconnection, failure and the like of the connector) when the interlock device including an interlock ring is in failure. It has the following components: an interlock ring 16 provided with the HV connector 7 for connecting the electric compressor to the HV battery 8; a voltage level generating part for generating different voltage levels based on the state of the interlocking ring; a voltage level determination unit for outputting a determination result (L/H signal) based on the voltage level generated by the voltage level generation unit; and a controller 9 for outputting the L/H signal and diagnosing the state of the interlocking ring based on the output of the voltage level determination unit.

Description

Interlocking device for high-voltage equipment

Technical Field

The present invention relates to an interlock device for detecting disconnection of a connector for connecting a high-voltage device such as an electric compressor mounted on a vehicle to a high-voltage power supply.

Background

An electric compressor constituting, for example, an air conditioning device of a vehicle is connected to a high voltage power supply (HV battery) by a connector (HV connector). Since there is a risk of an accident such as an electric shock occurring when the connector is disconnected, an interlock ring of an interlock device is provided together with the connector in order to detect the disconnection of the connector.

The interlock ring also becomes a closed circuit or an open circuit when the connector is connected or disconnected (disengaged). A signal (H level or L level) of a fixed level is output from the controller to the interlock loop, and the interlock loop is opened and the signal level to the controller is inverted, thereby detecting disconnection (disconnection) of the connector (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-11959

Disclosure of Invention

Technical problem to be solved by the invention

As described above, the conventional interlock device has the following problems: that is, although the disconnection of the connector can be detected, the disconnection of the connector cannot be accurately detected when a power supply short circuit or a ground short circuit occurs in the interlock ring or when a failure occurs in the interlock device itself.

The present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide an interlock device for high-voltage equipment, which is capable of diagnosing a connected or disconnected state of a connector when the interlock device is normal, and accurately detecting a disconnection of the connector as an unsafe state (disconnection, failure, etc. of the connector) even when the interlock device itself including an interlock ring failure has failed.

Technical scheme for solving technical problem

In order to solve the above problem, an interlock device for a high-voltage device according to the present invention includes: an interlock ring provided together with an HV connector for connecting a high-voltage device mounted on a vehicle to a high-voltage power supply; a voltage level generating part that generates different voltage levels based on a state of the interlock loop; a voltage level determination section that outputs a determination result composed of an L/H signal according to the voltage level generated by the voltage level generation section; a failure diagnosis unit which diagnoses a state of the interlock loop based on an output of the voltage level determination unit; and a detection switching signal output part outputting an L/H signal, the voltage level generation part generating different voltage levels according to a state of the interlock loop and an output of the detection switching signal output part, and the fault diagnosis part diagnosing the state of the interlock loop according to a combination of an output of the voltage level determination part with respect to an output of the detection switching signal output part.

In the interlock device for high voltage equipment according to the invention of claim 2, in each of the above inventions, the failure diagnosis unit diagnoses a failure of the interlock device itself including at least a failure of the interlock ring, a failure of the HV connector, and a failure of the connected or disconnected HV connector.

In the interlock device for high voltage equipment according to the invention of claim 3, in each of the above inventions, the voltage level generating section is constituted by a voltage dividing circuit having a plurality of resistors and connected to the same power supply as the voltage level determining section, and the interlock ring is connected to the voltage dividing circuit.

In the interlock device for high voltage equipment according to the invention of claim 4, in each of the above inventions, the voltage level determination section is constituted by a plurality of comparators.

The interlock device for high-voltage equipment according to the invention of claim 5 is characterized in that, in each of the above inventions, it is provided in the high-voltage equipment.

In the interlock device for high-voltage equipment according to the invention of claim 6, in each of the above inventions, the high-voltage equipment is an electric compressor mounted on a vehicle.

Effects of the invention

The high-voltage equipment coupler of the invention comprises: an interlock ring provided together with an HV connector for connecting a high-voltage device mounted on a vehicle to a high-voltage power supply; a voltage level generating part that generates different voltage levels based on a state of the interlock loop; a voltage level determination section that outputs a determination result composed of an L/H signal according to the voltage level generated by the voltage level generation section; a failure diagnosis unit which diagnoses a state of the interlock loop based on an output of the voltage level determination unit; and a detection switching signal output section that outputs an L/H signal, the voltage level generation section generates different voltage levels according to the state of the interlock loop and the output of the detection switching signal output section, and the failure diagnosis section diagnoses the state of the interlock loop according to a combination of the output of the voltage level determination section with respect to the output of the detection switching signal output section, so that it is possible to diagnose a failure of the interlock device itself including a failure of the interlock loop and a connection and non-connection of the HV connector by the failure diagnosis section as shown in the invention of claim 2.

Thus, even when the interlock device itself for high voltage equipment including the failure of the interlock ring fails, the disconnection of the connector can be accurately diagnosed (erroneous diagnosis such as the connection of the connector does not occur) as an unsafe state (disconnection of the connector, failure, etc.).

Further, according to the invention of claim 3, when the voltage level generating section is configured by a voltage dividing circuit connected to the same power supply as the voltage level determining section and having a plurality of resistors, and the interlock loop is connected to the voltage dividing circuit, the voltage level generated by the voltage level generating section changes in the state of the interlock loop (closed loop, open loop, power short circuit, ground short circuit), and the above-described situation can be diagnosed accurately.

Further, according to the invention of claim 4, when the voltage level determination unit is configured by a plurality of comparators, the determination result including the L/H signal can be output to the voltage level of the voltage level generation unit which changes based on the state of the interlock loop.

In particular, according to the invention of claim 5, by providing the interlock device for high-voltage equipment in the high-voltage equipment, it is possible to perform failure diagnosis on the high-voltage equipment side without connecting the interlock ring to the controller of the vehicle, as in the case of the high-voltage equipment mounted on the vehicle, for example.

The high-voltage device interlock device is extremely effective when applied to an electric compressor of a high-voltage device mounted on a vehicle as described in the invention of claim 6.

Drawings

Fig. 1 is a functional block diagram of an inverter 1 for an electric compressor as an embodiment of a high-voltage device to which the present invention is applied.

Fig. 2 is a diagram showing one embodiment of a circuit of the state detection determination circuit 17 in fig. 1.

Fig. 3 is a diagram illustrating the state of the interlocking ring of fig. 2, the voltage levels at the respective points, and the operation of the switch 31.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 shows functional blocks constituting an inverter 1 for an electric compressor as a vehicle air conditioner to which the high voltage device of the present invention is applied. In fig. 1, reference numeral 2 denotes a motor for driving the electric compressor, and is driven by an inverter output circuit 3. Reference numeral 4 denotes a high voltage detection sensor, and 6 denotes a filter/capacitor, which are connected to an HV battery 8 as a high voltage power supply mounted on the vehicle via an HV connector 7.

Further, reference numeral 9 denotes a controller constituted by a microcomputer, and the controller 9 drives and controls the motor 2 of the electric compressor. The controller 9 is connected to a LIN transceiver (transmitter) 13 via a bidirectional digital isolator 11 and an optical coupler 12, and the LIN transceiver 13 is connected to a vehicle-side controller (ECU), not shown, via a connector (LV connector) 14 and a vehicle communication bus 15. Further, the controller 9 is connected to the inverter output circuit 3, outputs a drive signal and controls the inverter output circuit 3 in accordance with instruction information from the controller on the vehicle side obtained from the LIN transceiver 13.

Further, 16 is an interlock ring provided together with the HV connector 7, and when the HV connector 7 is connected, the loop is closed (closed circuit), and when not connected (disconnected), the loop is opened (open circuit). The interlock loop 16 is connected to a state detection decision circuit 17, and the state detection decision circuit 17 is connected to the controller 9.

The low-voltage power source LV +/LV-connected to the inverter is supplied to the inverter circuit as a 12V power source/LVGND. Further, 18 is a DC-DC converter that generates a 15V power supply 21, a 5V power supply (HV side) 22 from a 12V power supply 19 (low voltage power supply: fig. 2) introduced as LV +, the 15V power supply 21 is connected to the inverter output circuit 3, and the 5V power supply (HV side) 22 is connected to the controller 9, the state detection determination circuit 17. In addition, a 12V power supply 19, a 5V power supply (LV side) 23 are connected to the state detection determining circuit 17.

The detection switching signal output part and the failure diagnosis part of the controller 9, the interlock loop 16, and the state detection determination circuit 17 constitute the interlock device for high voltage equipment of the present invention. The high-voltage apparatus interlock device according to the present invention is provided in an electric compressor (high-voltage apparatus), and a range indicated on the HV side in the figure indicates the high-voltage side, and a range indicated on the LV side indicates the low-voltage side.

Next, fig. 2 shows an embodiment of a circuit loop of the state detection determination circuit 17 of fig. 1. The state detection/determination circuit 17 of the embodiment includes a circuit in which voltage dividing

resistors

28 and 29 and a switch 31 as a voltage level switching element are connected in series, a voltage dividing circuit 32 including a voltage dividing resistor 42 and a diode 41, a window comparator 36 including 2

comparators

33 and 34,

optical couplers

37 and 38, a driver 39, and the like.

In this case, the voltage dividing circuit 32 is connected between the 12V power supply 19 and LVGND, and the interlock loop 16 is connected between a connection point (E) of the voltage dividing resistor 28 and the voltage dividing resistor 29 of the voltage dividing circuit 32 and a connection point (D) of the diode 41 and the voltage dividing resistor 42. The diode 41 is connected to a connection point of the voltage-dividing resistor 29 and the switch 31, the direction of which is set to the forward direction. The voltage dividing resistor 42 is connected between the connection point (D) and LVGND.

A connection point (E) of the voltage dividing circuit 32 is connected to an inverting input terminal of the comparator 33 and a non-inverting input terminal of the comparator 34. The voltage level of the non-inverting input terminal of the comparator 33 is set to 8V as a threshold (F), and the voltage level of the inverting input terminal of the comparator 34 is set to 4V as a threshold (G). Further, the output (H) of the comparator 33 and the output (I) of the comparator 34 are connected to the optical coupler 38, and the output 44 of the optical coupler 38 and the resistor 46 are connected in series between the 5V power supply 22(HV side) and the HVGND. The junction (J) of the output 44 of the optical coupler 38 and the resistor 46 is connected to the input 49 of the controller 9.

An output terminal 51 of the controller 9 is connected to an input (a) of the optical coupler 37, and an output 47 of the optical coupler 37 is connected in series with a resistor 48 between the 5V power supply (LV side) 23 and LVGND. A connection point (B) between the output 47 of the optical coupler 37 and the resistor 48 is connected to the driver 39, and the switch 31 is configured to be switched by the driver 39. The voltage divider circuit 32 in fig. 2 constitutes a voltage level generating section of the present invention, and the window comparator 36 constitutes a voltage level determining section of the present invention. The controller 9 constitutes a failure diagnosis unit and a detection switching signal output unit of the present invention, and performs failure diagnosis based on a combination of a signal input from the input terminal 49 and a detection switching signal output from the output terminal 51.

With respect to the above-described configuration, the operation of the high-voltage-device interlock apparatus according to the embodiment will be described with reference to fig. 2 and 3. Fig. 3 shows the state of the interlock loop 16, the signal levels of the output terminal 51 and the input terminal 49 of the controller 9, the voltage levels of the points (a) to (J) in fig. 2, the operation of the switch 31, and the diagnostic result of the controller 9 based on these. First, the controller 9 alternately outputs an "L" level signal and an "H" level signal from the output terminal 51 at a prescribed period in the embodiment.

(1) When the high-voltage device interlock device is normal in a state where the HV connector 7 is connected

When the HV connector 7 is currently connected, the loop of the interlock ring 16 is also closed (closed loop), and the interlock ring 16 and the state detection determination circuit 17 of the high-voltage apparatus interlock device do not malfunction. When the signal (detection switching output signal) output from the output terminal 51 is at the "L" level, if the input (a) of the optical coupler 37 is at the "H" level, and the signal output from the output terminal 51 is at the "L" level, the input (a) of the optical coupler 37 is at the "H" level, and the output 47 of the optical coupler 37 is turned off, the voltage at the connection point (B) is at the "H" level, and the output of the driver 39 turns on (closes) the switch 31.

Here, when the

voltage dividing resistors

28, 29, and 42 have the same resistance value and the forward voltage of the diode 41 is set to 1V, the voltage level of the connection point (D) becomes 1V and the voltage level of the connection point (E) also becomes 1V by turning on the switch 31. When the voltage level of the connection point (E) becomes 1V, the output (H) of the comparator 33 becomes "H" level, and the output (I) of the comparator 34 becomes "L" level, so that the input of the optical coupler 38 becomes "L" level. When the input of the optical coupler 38 becomes "L" level, the output 44 is turned on, and the voltage at the connection point (J) becomes "L" level, and the signal at the input terminal 49 of the controller 9 also becomes "L" level.

On the other hand, when the signal output from the output terminal 51 becomes the "H" signal, the voltage of the input (a) of the optical coupler 37 becomes the "L" level, and the output 47 of the optical coupler 37 is turned on, so that the voltage of the connection point (B) becomes the "L" level, the driver 39 stops outputting, and the switch 31 is turned off (opened).

When the switch 31 is turned off, the voltage level at the connection point (D) becomes 6V, and the voltage level at the connection point (E) also becomes 6V (12V is divided by the voltage dividing resistors 28 and 42). When the voltage level of the connection point (E) becomes 6V, the output (H) of the comparator 33 becomes "H" level, and the output (I) of the comparator 34 also becomes "H" level, so that the input of the optical coupler 38 becomes "H" level. Thus, since the output 44 of the optical coupler 38 is turned off, the voltage at the connection point (J) becomes "H" level, and the signal at the input terminal 49 of the controller 9 also becomes "H" level.

When the signal of the input terminal 49 becomes "L" level when the signal of "L" level is output from the output terminal 51, and when the signal of the input terminal 49 becomes "H" level when the signal of "H" level is output, the controller 9 diagnoses that the HV connector 7 is in the connected state.

(2) When the high-voltage device interlock device is normal in a state where the HV connector 7 is not connected (disconnected)

Next, the following will be explained: that is, when the HV connector 7 is not connected, the loop of the interlock ring 16 is opened (open loop), and the interlock ring 16 and the state detection/determination circuit 17 of the high-voltage apparatus interlock device do not malfunction. In this case as well, when the signal output from the output terminal 51 of the controller 9 is at the "L" level, the voltage at the input (a) of the optical coupler 37 becomes the "H" level, and the output 47 of the optical coupler 37 is off, so that the voltage at the connection point (B) becomes the "H" level, and the output of the driver 39 turns on (closes) the switch 31.

Since the interlock loop 16 is now open, when the switch 31 is turned on, the voltage level at the connection point (E) is divided into 6V by the

voltage dividing resistors

28 and 29. When the voltage level of the connection point (E) becomes 6V, the output (H) of the comparator 33 becomes "H" level, and the output (I) of the comparator 34 also becomes "H" level, so that the input potential of the optical coupler 38 becomes "H" level. Thus, since the output 44 of the optical coupler 38 is turned off, the voltage at the connection point (J) becomes "H" level, and the signal at the input terminal 49 of the controller 9 also becomes "H" level.

On the other hand, when the signal output from the output terminal 51 becomes "H" level, the voltage of the input (a) of the optical coupler 37 becomes "L" level, and the output 47 of the optical coupler 37 is turned on, so that the voltage of the connection point (B) becomes "L" level, the driver 39 stops outputting, and the switch 31 is turned off (opened).

Since the interlock loop 16 is currently open, when the switch 31 is turned off, the voltage level at the connection point (D) is maintained at 0V, and the voltage level at the connection point (E) is 12V. When the voltage level of the connection point (E) becomes 12V, the output (H) of the comparator 33 becomes "L" level, and the output (I) of the comparator 34 becomes "H" level, so that the input of the optical coupler 38 becomes "L" level. Thus, since the output 44 of the optical coupler 38 is turned on, the voltage at the connection point (J) becomes "L" level, and the signal at the input terminal 49 of the controller 9 also becomes "L" level.

When the signal of the input terminal 49 becomes "H" level when the "L" level signal is output from the output terminal 51, and when the signal of the input terminal 49 becomes "L" level when the "H" level signal is output, the controller 9 diagnoses that the HV connector 7 is in the unconnected state.

(3) In the event of a power short circuit of interlocking ring 16

Next, a case where the interlock ring 16 is short-circuited to the power source (LV +) will be described. If the interlock loop 16 is short-circuited to the power source LV (+), the voltage level of the connection point (E) is 12V regardless of whether the signal outputted from the output terminal 51 of the controller 9 is "L" level or "H" level.

When the voltage level of the connection point (E) becomes 12V, the output (H) of the comparator 33 becomes "L" level, and the output (I) of the comparator 34 becomes "H" level, so that the input of the optical coupler 38 becomes "L" level. Thus, since the output 44 of the optical coupler 38 is turned on, the voltage at the connection point (J) becomes "L" level, and the signal at the input terminal 49 of the controller 9 also becomes "L" level.

When the signal of the input terminal 49 becomes "L" level when the "L" level signal is output from the output terminal 51, and when the signal of the input terminal 49 becomes "L" level when the "H" level signal is output, the controller 9 diagnoses a failure state (in this case, a power short failure occurs in the interlock loop 16).

(4) When interlocking ring 16 is shorted to ground

Next, a case where the interlock ring 16 is short-circuited to the power supply (LV-) will be described. When the interlock loop 16 is short-circuited to the ground, the connection point (E) is 0V which is a voltage level of the ground (LV-), regardless of whether the signal outputted from the output terminal 51 of the controller 9 is "L" level or "H" level.

When the voltage level of the connection point (E) becomes 0V, the output (H) of the comparator 33 becomes "H" level, and the output (I) of the comparator 34 becomes "L" level, so that the input of the optical coupler 38 becomes "L" level. Thus, since the output 44 of the optical coupler 38 is turned on, the voltage at the connection point (J) becomes "L" level, and the signal at the input terminal 49 of the controller 9 also becomes "L" level.

As described above, when the signal of the input terminal 49 becomes the "L" level when the "L" level signal is output from the output terminal 51 and the signal of the input terminal 49 also becomes the "L" level when the "H" level signal is output, the controller 9 diagnoses a failure state (in this case, a ground short fault occurs in the interlock loop 16).

(5) Other faults (e.g. short-circuit fault in output of optical coupler 37)

Next, a case where a failure such as a short circuit of the output 47 of the optical coupler 37 occurs will be described. When the output 47 of the optical coupler 37 is short-circuited and the switch 31 is kept off, the voltage level of the connection point (E) is 6V regardless of whether the signal output from the output terminal 51 of the controller 9 is "L" level or "H" level when the interlock ring 16 is in the connected state.

When the voltage level of the connection point (E) becomes 6V, the output (H) of the comparator 33 becomes "H" level, and the output (I) of the comparator 34 becomes "H" level, so that the input of the optical coupler 38 becomes "H" level. Thus, since the output 44 of the optical coupler 38 is turned off, the voltage at the connection point (J) becomes "H" level, and the signal at the input terminal 49 of the controller 9 also becomes "H" level.

As described above, when the signal of the input terminal 49 becomes "H" level when the "L" level signal is output from the output terminal 51, and the signal of the input terminal 49 also becomes "L" level when the "H" level signal is output, the controller 9 diagnoses a failure state (in this case, the short-circuit failure occurs in the output 47 of the optical coupler 37).

As described above in detail, the interlock device for high-voltage equipment according to the present invention includes: an interlock ring 16 provided together with an HV connector 7 for connecting an electric compressor (high-voltage device) mounted on a vehicle to an HV battery 8 (high-voltage power supply); a voltage level generating section that generates different voltage levels based on the state of the interlock ring 16; a voltage level determination unit that outputs a determination result (L/H signal) based on the voltage level generated by the voltage level generation unit; a controller 9 (failure diagnosis unit) for diagnosing the state of the interlock ring 16 based on the output of the voltage level determination unit by the controller 9; and a detection switching signal output unit that outputs an L/H signal, the voltage level generation unit generates different voltage levels according to the state of the interlock ring 16 and the output of the detection switching signal output unit, and the failure diagnosis unit diagnoses the state of the interlock ring 16 according to a combination of the output of the voltage level determination unit and the output of the detection switching signal output unit, so that it is possible to diagnose a failure of the interlock device itself including a failure of the interlock ring 16, and a connection and a disconnection of the HV connector by using the controller 9.

Thus, even when the interlock device itself for high-voltage equipment including the failure of the interlock ring 16 fails, the disconnection of the connector 7 can be accurately diagnosed (erroneous diagnosis such as the connector being in a connected state does not occur) as an unsafe state (connector not connected, failure, or the like).

In the embodiment, since the voltage level generating unit is constituted by the voltage dividing circuit 32 having the plurality of

voltage dividing resistors

28, 29, 42, the diode 41, and the switch 31 connected to the 12V power supply 19 (low voltage power supply), and the interlock ring 16 is connected to the voltage dividing circuit 32, the voltage level generated by the voltage level generating unit (the voltage level of the connection point (E)) changes due to the connection, disconnection, power supply short circuit, and ground short circuit of the interlock ring 16, and the above-described situation can be diagnosed accurately.

In particular, by providing the interlock device for high-voltage equipment to the electric compressor (high-voltage equipment) as in the embodiment, it is possible to perform failure diagnosis on the electric compressor side without connecting the interlock ring 16 to the controller of the vehicle.

In the embodiment, the high-voltage device interlock apparatus is applied to the electric compressor as the high-voltage device mounted on the vehicle, but the present invention is not limited to this, and is effective for various high-voltage devices mounted on the vehicle.

In the embodiment, the failure of the optical coupler 37 is exemplified as the failure of the state detection and determination circuit 17, but a failure of another element can be diagnosed similarly. The voltage level determination unit is configured by the window comparator 36 shown in the embodiment, AND the logical AND (AND) of the two outputs of the window comparator 36 is obtained as the determination result, but the specific circuit configuration is not limited to this, AND the two outputs of the window comparator 36 may be individually input to the controller 9 AND diagnosed. However, according to the circuit configuration described in the embodiment, the disconnection of the HV connector 7 can be accurately detected as an unsafe state (disconnection of the connector, failure, or the like) for each of the input terminal of the controller 9 and the optical coupler.

The voltage of the 12V power supply 19 (low voltage power supply) connected to the voltage level generation unit and the voltage level determination unit is not necessarily limited to 12V, and the interlock device is allowed to operate normally as long as the voltage is within the LV + power supply input voltage range defined by the inverter.

Description of the reference symbols

1 inverter for electric compressor

2 electric motor

3 inverter output circuit

7 HV connector

8 HV battery (high voltage power supply)

9 controller (failure diagnosis part, detection switching signal output part)

16 interlocking rings

17 State detection judging circuit (Voltage level generating part, Voltage level judging part)

1912V Power supply (Low-voltage power supply)

28. 29, 42 voltage dividing resistor (voltage level generating part)

31 switch (Voltage level generating part)

33. 34 comparator

36 window type comparator (Voltage level determination part)

37. 38 optical coupler

Diode 41 (Voltage level generating part)

49 input terminal (failure diagnosis part)

And an output terminal 51 (detection switching signal output unit).

Claims

1. An interlock device for a high-voltage device mounted on a vehicle, the interlock device comprising:

an interlock ring provided with an HV connector for connecting the high voltage device to a high voltage power supply;

a voltage level generating part generating different voltage levels based on a state of the interlock ring;

a voltage level determination section that outputs a determination result composed of an L/H signal based on the voltage level generated by the voltage level generation section;

a failure diagnosis unit that diagnoses a state of the interlock ring based on an output of the voltage level determination unit; and

a detection switching signal output section that outputs an L/H signal,

the voltage level generating part generates different voltage levels based on the state of the interlock loop and the output of the detection switching signal outputting part,

and the failure diagnosing section diagnoses the state of the interlock loop based on a combination of an output of the voltage level determining section with respect to an output of the detection switching signal outputting section.

2. An interlock device for high voltage equipment according to claim 1,

the failure diagnosis unit diagnoses at least a connection and a disconnection of the HV connector, and a failure of the interlock device itself including a failure of the interlock ring.

3. An interlock device for high voltage equipment according to claim 1 or 2,

the voltage level generating part is composed of a voltage dividing circuit connected to the same power supply as the voltage level determining part and having a plurality of resistors, and the voltage dividing circuit is connected to the interlock loop.

4. An interlock device for high voltage equipment according to any one of claims 1 to 3,

the voltage level determination unit is composed of a plurality of comparators.

5. An interlock device for high voltage equipment according to any one of claims 1 to 4,

the interlock device for the high voltage device is provided in the high voltage device.

6. An interlock device for high voltage equipment according to any one of claims 1 to 5,

the high-voltage device is an electric compressor mounted on the vehicle.