Circuit Apparatus for Protecting a Pre-Charge Resistance Using an Interlock Switch
The present invention relates to a circuit apparatus for protecting a pre-charge resistance using an inter-lock switch, and more particularly, to a circuit apparatus for protecting a pre-charge resistance by controlling a current flowing to a voltage transformer of an electric vehicle using an inter-lock switch and a polyswitch. The present invention provides a circuit apparatus for protecting a pre-charge resistance using an inter-lock switch, including a pre-charge resistance, a pre-charge relay and a main relay placed between a battery of a hybrid electric vehicle and a voltage transformer, wherein the circuit apparatus includes an inter-lock switch which is operated complementarily with the pre-charge relay and is for preventing continuous flow of an overcurrent to the voltage transformer and the resulting damage of the pre-charge resistance.
1 . A circuit apparatus for protecting a pre-charge resistance using an inter-lock switch, comprising a pre-charge resistance, a pre-charge relay and a main relay placed between a battery of a hybrid electric vehicle and a voltage transformer,
wherein the circuit apparatus further comprises an inter-lock switch which is operated complementarily with the pre-charge relay and is for preventing continuous flow of an overcurrent to the voltage transformer and the resulting damage of the pre-charge resistance.
2 . The circuit apparatus for protecting a pre-charge resistance using an inter-lock switch as set forth in claim 1 , wherein the inter-lock switch is placed between a DC link capacitor and a low voltage DC-DC converter which are included in the voltage transformer.
3 . The circuit apparatus for protecting a pre-charge resistance using an inter-lock switch as set forth in claim 1 , further comprising:
a polyswitch which cuts off the overcurrent flowing through the pre-charge resistance as its temperature is raised and its resistance value is increased when the overcurrent flows continuously to the pre-charge resistance.
4 . The circuit apparatus for protecting a pre-charge resistance using an inter-lock switch as set forth in claim 3 , wherein the polyswitch is placed between the pre-charge resistance and the pre-charge relay or between the battery of the hybrid electric vehicle and the pre-charge resistance.