Insulation detecting circuit, power converting device and insulation impedance value detecting method

A power converting device, comprising:

• a dc-dc converting circuit configured to convert a dc input voltage to a dc bus voltage;
• a dc-ac converting circuit electrically coupled to the dc-dc converting circuit and configured to convert the dc bus voltage to an ac voltage;
• and
• an insulation detecting circuit electrically coupled to the dc-dc converting circuit, the insulation detecting circuit comprising:
• a first switching unit;
• a second switching unit electrically coupled to the first switching unit;
• a detecting resistor;
• a processing unit configured to control the first switching unit and the second switching unit;
• and
• a voltage detecting unit configured to obtain a first voltage value across the detecting resistor when the processing unit controls the first switching unit to be on and the second switching unit to be off, wherein
• the voltage detecting unit is further configured to obtain a second voltage value across the detecting resistor when the processing unit controls the first switching unit to be off and the second switching unit to be on, and wherein
• the processing unit is further configured to operate in a first mode and calculate an insulation impedance value of the power converting device according to the first voltage value and the second voltage value.

An insulation impedance value detecting method, comprising:

• in a first mode, controlling, by a processing unit, a first switching unit to be on and a second switching unit to be off;
• detecting, by a voltage detecting unit, a first voltage value across a detecting resistor;
• controlling, by the processing unit, the first switching unit to be off and the second switching unit to be on;
• detecting, by the voltage detecting unit, a second voltage value across the detecting resistor;
• and
• calculating, by the processing unit, an insulation impedance value of a power converting device according to the first voltage value and the second voltage value.