E-T-A HVR10 high voltage contactor for electric vehicle applications: arc-free switching made easy

High Voltage Switching (ON and OFF) with the HVR10 high voltage contactor During the ON operation the HVR10 in the negative path of the high voltage battery system is closed. The pre-charge capacitors are charged through the precharge circuit. As soon as the pre-charge capacitors are fully charged the voltage difference is reduced, the battery management system switches the HVR10 in the positive path. The bypass circuitry of the HVR10 is unique in this application. The use of semiconductors combined with an auxiliary relay ensures reliable physical isolation. Initially, the auxiliary relay closes. The semiconductors become low-resistance creating a path for the current, and the HVR10 monitors the current rise. If the current sees normal current flow, it will allow the current to flow through the main contact. Now the main contact is closed and the current can flow via the main contact. Finally, the semiconductors become high-resistance again, directing the current flow through the main contact. In a short circuit situation the current rises too fast. When this happens,the semiconductor circuit becomes high-resistance again, and the auxiliary relay opens. The HVR10 independently from the battery managment system detects critical operating states and prevents switching on in the event of an error. After the HVR10 has switched on, the precharge relay can open. Now the high voltage loads are supplied with power. Both HVR10s are designed for bidirectional current flow and are capable of switching on and off in both directions at a consistently high rupture capacity. In the event of an overload, the system ensures reliable shutdown of up to 2000 Amps at 1000 Volts multiple times thus closing a critical safety gap. During the shutdown cycle, the semiconductor initially becomes low-resistance again. The main contact opens so the current can flow again completely via the bypass. Afterwards, the semiconductor becomes high-resistance again. As a result, no more current flows through the bypass. As soon as this happens, the auxiliary relay can re-open and ensures galvanic isolation. After the HVR10 in the positive path has switched off, the HVR10 in the negative path of the high voltage battery can also open with power off.