The insulation resistance tester is direct-current high-voltage power supply

The utility model provides a DC high-voltage power supply for an insulation resistance tester, which comprises a low-voltage DC power supply, a power converter, a voltage doubling rectifying circuit and a PWM controller, and the power converter comprises a switch tube S1, a switch tube S2, a boosting transformer T1 and a capacitor C3. According to the power converter provided by the utility model,zero-voltage turn-off of the switch tube S1 and zero-voltage turn-on and turn-off of the switch tube S2 are realized through the clamping capacitor C3, the leakage inductor of the boosting transformer T1 and the parasitic capacitor of the switch tube, so that the switching loss is reduced; forward conversion is adopted, an active clamping circuit composed of a switch tube S2 and a capacitor C3 isused for achieving automatic reset of the magnetic flux of the boosting transformer T1, no reset measure needs to be additionally added, the exciting current I2 can circulate in the positive and negative directions, the magne