Power conversion device and method for controlling power conversion device
A power conversion device which converts power between a power grid and a DC power supply, includes: AC/DC converters for performing conversion from AC power to DC power or from DC power to AC power between the power grid and the DC power supply; a capacitor provided on the DC power supply side of the AC/DC converters and storing DC power; and a step-up unit for charging the capacitor.
1. A power conversion device which converts power between a power grid and a DC power supply, the power conversion device comprising:
an AC/DC converter for performing conversion from AC power to DC power or from DC power to AC power between the power grid and the DC power supply;
a capacitor provided on a DC power supply side of the AC/DC converter and storing the DC power;
a step-up unit for charging the capacitor; and
an abnormality detection device provided on the DC power supply side of the AC/DC converter, wherein
the step-up unit generates voltage for insulation diagnosis based on an insulation diagnosis reference voltage, wherein a source of the insulation diagnosis reference voltage is different from the DC power supply, and applies the voltage for insulation diagnosis to the DC power supply side of the AC/DC converter, to charge the capacitor.
2. The power conversion device according to claim 1 , wherein
the step-up unit generates voltage for pre-charging based on voltage of the DC power supply, to charge the capacitor.
3. The power conversion device according to claim 2 , wherein
the step-up unit includes a switching circuit for switching between a signal of the insulation diagnosis reference voltage and a signal of the voltage of the DC power supply.
4. The power conversion device according to claim 3 , wherein
a field effect transistor is used for the switching circuit.
5. The power conversion device according to claim 3 , wherein
an analog switch is used for the switching circuit.
6. The power conversion device according to claim 3 , wherein
an electromagnetic-contact-type relay is used for the switching circuit.
7. The power conversion device according to claim 1 , wherein
the DC power supply is a storage battery inside an electric vehicle.
8. The power conversion device according to claim 1 , wherein
the abnormality detection device is composed of both or one of a ground fault detection circuit and a current sensor.
9. The power conversion device according to claim 1 , wherein
the step-up unit generates the voltage for insulation diagnosis based on the insulation diagnosis reference voltage, using a switch and an amplifier.
10. The power conversion device according to claim 9 , wherein
the step-up unit further includes a diode between the switch and the amplifier.
11. A method for controlling a power conversion device which includes an AC/DC converter for converting power between a power grid and a DC power supply, a capacitor provided on a DC power supply side of the AC/DC converter and storing DC power, and a step-up unit for generating voltage to charge the capacitor, the method comprising:
an insulation diagnosis step of generating voltage for insulation diagnosis, by the step-up unit, and based on an insulation diagnosis reference voltage, wherein a source of the insulation diagnosis reference voltage is different from the DC power supply, and applying the voltage for insulation diagnosis between the DC power supply and the AC/DC converter; and
a pre-charge step of generating voltage for pre-charging based on voltage of the DC power supply, by the step-up unit, to charge the capacitor, wherein
the insulation diagnosis step and the pre-charge step are performed before interconnection of the power conversion device with the DC power supply is performed.
12. The power conversion device according to claim 2 , wherein
the DC power supply is a storage battery inside an electric vehicle.
13. The power conversion device according to claim 2 , wherein
the abnormality detection device is composed of both or one of a ground fault detection circuit and a current sensor.
14. The power conversion device according to claim 3 , wherein
the DC power supply is a storage battery inside an electric vehicle.
15. The power conversion device according to claim 3 , wherein
the abnormality detection device is composed of both or one of a ground fault detection circuit and a current sensor.