Safety device for an electric DC grid, onboard electrical system for a vehicle, vehicle, and DC charging station

An electric vehicle or hybrid vehicle comprising:

• an onboard electrical system comprising a safety device, which comprises
• a first voltage measuring device arranged between a positive potential line and a reference potential line and configured to measure a voltage between the positive potential line and the reference potential line;
• a second voltage measuring device arranged between a negative potential line and the reference potential line and configured to measure a voltage between the negative potential line and the reference potential line,
• a protective circuit configured to reduce an electric shock caused by Y-capacitors of the electric DC grid, wherein the protective circuit comprises
• a first circuit breaker between the positive potential line and the reference potential line;
• and
• a second circuit breaker between the negative potential line and the reference potential line,
• wherein a plurality of tripping criteria are predefined and the first circuit breaker or the second circuit breaker is actuatable so as to close exclusively in event of all predefined tripping criteria being met as determined by the first voltage measuring device or the second voltage measuring device,
• wherein the tripping criteria comprise
• a voltage deviation of a voltage applied between the positive potential line and the reference potential line and a voltage applied between the negative potential line and the reference potential line from a previously determined voltage value,
• a voltage changes in the voltage applied between the positive potential line and the reference potential line and the voltage applied between the negative potential line and the reference potential line,
• the voltage applied between the positive potential line and the reference potential line is of the opposite sign to the voltage applied between the negative potential line and the reference potential line, and
• an absence of a cyclical repetition of other tripping criteria,
• wherein the first circuit breaker or the second circuit breaker are actuatable only if
• the voltage deviation of the voltage present between the positive potential line and the reference potential line and the voltage present between the negative potential line and the reference potential line from the previously determined voltage value exceeds a predefined limit value, and
• the voltage changes of the voltage applied between the positive potential line and the reference potential line and the voltage applied between the negative potential line and the reference potential line exceeds a predefined limit value, and
• the voltage applied between the positive potential line and the reference potential line and is of the opposite sign to the voltage applied between the negative potential line and the reference potential line, and
• if the absence of the cyclical repetition of the other tripping criteria is determined.

A high-voltage DC charging station, comprising:

• a safety device, which comprises
• a first voltage measuring device arranged between a positive potential line and a reference potential line and configured to measure a voltage between the positive potential line and the reference potential line;
• a second voltage measuring device arranged between a negative potential line and the reference potential line and configured to measure a voltage between the negative potential line and the reference potential line,
• a protective circuit configured to reduce an electric shock caused by Y-capacitors of the electric DC grid, wherein the protective circuit comprises
• a first circuit breaker between the positive potential line and the reference potential line;
• and
• a second circuit breaker between the negative potential line and the reference potential line,
• wherein a plurality of tripping criteria are predefined and the first circuit breaker or the second circuit breaker is actuatable so as to close exclusively in event of all predefined tripping criteria being met as determined by the first voltage measuring device or the second voltage measuring device,
• wherein the tripping criteria comprise
• a voltage deviation of a voltage applied between the positive potential line and the reference potential line and a voltage applied between the negative potential line and the reference potential line from a previously determined voltage value,
• a voltage changes in the voltage applied between the positive potential line and the reference potential line and the voltage applied between the negative potential line and the reference potential line,
• the voltage applied between the positive potential line and the reference potential line is of the opposite sign to the voltage applied between the negative potential line and the reference potential line, and
• an absence of a cyclical repetition of other tripping criteria,
• wherein the first circuit breaker or the second circuit breaker are actuatable only if
• the voltage deviation of the voltage present between the positive potential line and the reference potential line and the voltage present between the negative potential line and the reference potential line from the previously determined voltage value exceeds a predefined limit value, and
• the voltage changes of the voltage applied between the positive potential line and the reference potential line and the voltage applied between the negative potential line and the reference potential line exceeds a predefined limit value, and
• the voltage applied between the positive potential line and the reference potential line and is of the opposite sign to the voltage applied between the negative potential line and the reference potential line, and
• if the absence of the cyclical repetition of the other tripping criteria is determined.