High-voltage system and failure diagnosis method for high-voltage system
Provided are a reliable high-voltage system and a failure diagnosis method thereof, in which a vibration damping mechanism using an electrorheological fluid as a working fluid is a load, and can prevent electric shock due to leakage current and the influence on surrounding electronic devices. There are provided a first circuit that includes a power source and a ground, a second circuit that is magnetically coupled to the first circuit via a transformer and includes a load connected to the ground, a controller that is connected to the ground, a third circuit that is connected to the second circuit and the ground, a first resistor that is provided between a connection point at a high potential end of the second circuit and the ground, and a second resistor that is provided between a connection point at a low potential end of the second circuit and the ground, and has a resistance value different from a resistance value of the first resistor.
1. A high-voltage system, comprising:
a first circuit that includes a power source and a ground;
a second circuit that is magnetically coupled to the first circuit via a transformer and includes a load connected to the ground;
a controller that is connected to the ground;
a third circuit that is connected to the second circuit and the ground;
a first resistor that is provided between a connection point at a high potential end of the second circuit and the ground; and
a second resistor that is provided between a connection point at a low potential end of the second circuit and the ground, and has a resistance value different from a resistance value of the first resistor;
wherein a resistance value (R40) of the second resistor is calculated by Inequality 1:
R
40
≤
R
load
_
min
·
R
39
R
load
_
min
+
R
39
·
V
CT
_
max
V
load
_
max
-
V
CT
_
max
.
2. The high-voltage system according to claim 1 , wherein the load is a vibration damping mechanism.
3. The high-voltage system according to claim 2 , wherein a working fluid of the vibration damping mechanism is an electrorheological fluid.
4. The high-voltage system according to claim 3 , wherein
the vibration damping mechanism includes
an inner cylinder into which a rod is inserted,
an outer cylinder that is provided outside the inner cylinder,
an intermediate cylinder that is an electrode provided between the inner cylinder and the outer cylinder, formed with a passage, between the inner cylinder and the outer cylinder, through which the electrorheological fluid flows from one end side to the other end side of the vibration damping mechanism in an axial direction as the rod reciprocates,
a rod guide that is provided to close an end portion of the one end side of the inner cylinder and the outer cylinder, and supports the rod,
a base valve that is provided in an end portion of the other end side of the inner cylinder and the outer cylinder, and
a seal member that seals the rod guide and an end portion of one end side of the intermediate cylinder, and
the inner cylinder, the outer cylinder, the base valve, and the rod guide are fixed to each other while maintaining a residual axial force.
5. The high-voltage system according to claim 2 , wherein the vibration damping mechanism is attached to at least two wheels of a vehicle.
6. The high-voltage system according to claim 1 , wherein the second circuit and the load are connected by a cable.
7. The high-voltage system according to claim 6 , wherein the first circuit, the transformer, the second circuit, the controller, the third circuit, the first resistor, the second resistor, the cable, and at least one additional load are included, and the first circuit, the transformer, the second circuit, the controller, the third circuit, the first resistor, and the second resistor, are stored in one housing.
8. The high-voltage system according to claim 1 , wherein the third circuit is a current detection unit for detecting a current of the load.
9. The high-voltage system according to claim 1 , wherein a resistance value of the second resistor is lower than a resistance value of the first resistor.
10. A high-voltage system, comprising:
a first circuit that includes a power source and a ground;
a second circuit that is magnetically coupled to the first circuit via a transformer and includes a load connected to the ground;
a controller that is connected to the ground;
a third circuit that is connected to the second circuit and the ground;
a first resistor that is provided between a connection point at a high potential end of the second circuit and the ground; and
a second resistor that is provided between a connection point at a low potential end of the second circuit and the ground, and has a resistance value different from a resistance value of the first resistor;
wherein, when a voltage across the second resistor is equal to or higher than a predetermined threshold voltage, an operation of the first circuit is stopped or an alarm is output.
11. The high-voltage system according to claim 10 , wherein the threshold voltage (Vfault) is calculated by the following expression:
V
fault
≤
R
40
R
load
_
max
·
R
39
R
load
_
max
+
R
39
·
R
40
·
V
out
_
min
.
12. A failure diagnosis method for a high-voltage system which includes:
a first circuit that includes a power source and a ground;
a second circuit that is magnetically coupled to the first circuit via a transformer and includes a load connected to the ground;
a controller that is connected to the ground;
a third circuit that is connected to the second circuit and the ground;
a first resistor that is provided between a connection point at a high potential end of the second circuit and the ground; and
a second resistor that is provided between a connection point at a low potential end of the second circuit and the ground, and has a resistance value different from a resistance value of the first resistor,
wherein, when a voltage across the second resistor is equal to or higher than a predetermined threshold voltage, it is determined that the high-voltage system has failed.
13. The failure diagnosis method for the high-voltage system according to claim 12 , wherein the threshold voltage (Vfault) is calculated by the following expression:
V
fault
≤
R
40
R
load
_
max
·
R
39
R
load
_
max
+
R
39
+
R
40
·
V
out
_
min
.