Short-circuit protection apparatus, short-circuit protection method for target circuit, and power conversion device

A short-circuit protection apparatus comprising:

• a first detection branch coupled in parallel to a first terminal of a target circuit and a second terminal of the target circuit, wherein the first detection branch comprises:
• a first sampling resistor, wherein a first sampling voltage is measured across the first sampling resistor;
• and
• a first sampling capacitor coupled in parallel to the first sampling resistor;
• a second detection branch coupled in parallel to the first terminal and the second terminal and comprising a second sampling resistor, wherein a second sampling voltage is measured across the second sampling resistor, and
• wherein when the target circuit is working, a difference between a second absolute value of the second sampling voltage and a first absolute value of the first sampling voltage is a first difference;
• and
• a controller coupled to the first detection branch and the second detection branch and configured to:
• obtain a comparison result between the first absolute value and the second absolute value;
• and
• control the target circuit to stop working when the difference between the second absolute value and the first absolute value is a second difference, wherein the first difference is greater than the second difference.