Patent ID: 12202357

DETAILED DESCRIPTION

FIG.1shows a schematic block diagram of a high-voltage (HV) electric device, according to an embodiment of the present disclosure. The high-voltage (HV) electrical device is any electrical device which operates with high voltage and connected to a high voltage line. Examples of the HV electrical device include, but not limited to, a HV plug, a HV charger, and a DC-DC converter, a HV Motor Control Unit, a HV Motor, a HV On-board Charger, a HV AC Compressor, a HV Battery. The HV electrical device10may be used in many applications, but not limited to, an electric vehicle or a hybrid vehicle.

The HV electrical device10comprises a connector20for connecting to a HV line. The HV electrical device10also has a low-voltage line30connected to a controller. The controller may or may not be a part of the HV electrical device10. For instance, the controller may be a part of the electrical vehicle. A resistor is connected in parallel to the low-voltage line30. In other words, the HV electrical device10is connected to the low-voltage line30through the resistor. One or more HV electrical devices10are connected to a HV line. The HV electrical devices10are also connected to the low-voltage line30through respective resistors. The resistance value of the resistors connected to each HV electrical device10is different. When there is a disconnection of one or more HV electrical devices10, the disconnected HV electrical device10can be identified based on the variation in the current drawn in the low-voltage line. Hence the disconnection in high-voltage interlock as well as precise identification of the disconnected HV electrical device10is possible. As a result, appropriate safety measures can be taken immediately. Therefore, safety of the user is improved.

FIG.2shows a schematic circuit diagram of a HV electrical system20employing a safety circuit. The HV electrical system is a part of a vehicle such as electric vehicle or a hybrid vehicle. The HV electrical system comprises one or more HV electrical devices10such as a HV plug, a HV charger, and a DC-DC converter, a HV Motor Control Unit, a HV Motor, a HV On-board Charger, a HV AC Compressor, a HV Battery, etc.

The safety circuit100of the HV electrical system comprises a low-voltage line30. A resistor40is connected in parallel to the low-voltage line30. In other words, the HV electrical device10is connected to the low-voltage line30through the resistor40.

In an embodiment of the disclosure, each HV electrical device30has integral resistor40of different resistance value. A controller50is connected to the HV electrical devices10through the low-voltage line30. The controller50may be a part of the vehicle such as electrical vehicle or hybrid vehicle. The controller50is connected to a low-voltage battery.

The controller50identifies the disconnection of one or more HV electrical devices10, based on the variation in the current drawn in the low-voltage line30. When all the HV electrical devices10are connected and working, the controller50knows the current drawn normally in the low-voltage line30. When a specific HV electrical device10is disconnected, the current variation can be detected and based on the variation in the current, the controller50identifies the disconnected HV electrical device10with the help of the pre-known resistance value of the corresponding resistor40. For example, the effective resistance and the total current drawn in the low-voltage line30, when all the HV electrical devices10are connected is stored beforehand by the controller50. When a particular HV electrical device10is disconnected, the variation in the current drawn in the low-voltage line30is detected and accordingly, the disconnected HV electrical device10is precisely identified.

Hence the disconnection in high-voltage interlock as well as precise identification of the disconnected HV electrical device10is possible. As a result, appropriate safety measures can be taken immediately which improves the overall safety of the HV electrical system.

In an embodiment of the disclosure, the different current values through the low-voltage line30are calibrated with a certain threshold range to identify which of the HV electrical device10has is triggered the High Voltage Interlock fault.FIG.3shows a graph showing the relation between current drawn and set of resistors of HV electrical devices10, according to an embodiment of the present disclosure. The same relation is explained in a below table.

EffectivePossibleResistanceCurrentCurrentHighLowsituations(Ω)(A)(mA)ThresholdthresholdR1, R2, R329.410.408408428388R2, R333.330.36360380340R3, R141.670.288288308268R1, R271.430.168168188148R1250.000.048486828R2100.000.12120140100R350.000.24240260220NoNoLimitedLimitedresistorsresistanceby VCUby VCU

In this example, there are three HV electrical devices10are connected to the low-voltage line30, through their respective resistors R1, R2, R340. The controller50knows the lower and upper threshold of current values corresponding to each HV electrical device10beforehand. When a specific HV electrical device10is disconnected, the variation in current is detected by the controller50and it is checked with the different threshold ranges of current corresponding to different HV electrical devices10and their resistors40. For example, as shown inFIG.3, the lower range and higher threshold of current corresponding to 3rd HV electrical device or the corresponding resistor R3is 220 and 260 mA, respectively. The current drawn is detected as 240 mA. Hence the controller50identifies that there is a disconnection of 3rd HV electrical device10.

Depending on which HV electrical device10has triggered HVIL fault and the resistor value, the current flow in the low voltage line30changes, which is detected by the controller50and accordingly appropriate safety measures are taken.

In an embodiment of the disclosure, where the safety circuit100is employed in a vehicular application, the controller50selectively turns on a limp-home mode, a drive stop mode or an emergency shut down mode, depending on the criticality of the disconnected HV electrical device10and the current state of the vehicle. For instance, when the criticality of the disconnected HV electrical device10is less, then the controller50turns on the limp-home mode, so that the vehicle can be driven with limited functionalities to a nearby garage or service center. When the criticality of the disconnected HV electrical device is medium, the drive stop mode is turned on by the controller50, where vehicle can be driven, and certain electrical functions like AC, etc., are turned off. If the criticality of the disconnected HV electrical device10is high, the emergency shut down mode is turned on by the controller50so that all the functionalities are switched off and vehicle is also shut down to improve the safety.

It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this disclosure. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the disclosure is only limited by the scope of the claims.