Vehicle charging apparatus, vehicle charging control method, and vehicle charging system

A vehicle charging control method carried out in order to charge a vehicle driving battery mounted in a vehicle from an external power source external to the vehicle, the vehicle charging control method carried out by a vehicle charging apparatus mounted in the vehicle,

• the vehicle charging apparatus comprising:
• a charging circuit that charges the vehicle driving battery, an input side of the charging circuit being connected to the external power source via a first switching device and an output side of the charging circuit being connected to the vehicle driving battery in the order of a DC/DC converter and a second switching device, the DC/DC converter connected to an auxiliary battery that is a drive source for an in-vehicle device;
• a charging control unit that controls the charging circuit and is connected to a signal line of a pilot signal output from a switching control circuit that controls the first switching device;
• an external power supply enabling circuit connected to the signal line to change a potential of the signal line, and
• a power supply unit that supplies power to the charging control unit,
• the power supply unit being a capacitor charging circuit provided on a charging path that connects the signal line and the charging control unit, and the capacitor charging circuit supplies power to the charging control unit, and
• the capacitor charging circuit includes, in order from the signal line of the charging path, a first resistor, a first switch, a first diode arranged such that an anode is toward the first switch and a cathode is toward the charging control unit, and a capacitor
• the vehicle charging control method comprising:
• when a voltage of the auxiliary battery drops,
• actuating, by the charging control unit, the charging circuit in a state in which the second switching device is open, and starting charging the auxiliary battery by the DC/DC converter;
• and
• after starting charging the auxiliary battery, closing the second switching device, and starting charging the vehicle driving battery by the charging circuit.

A vehicle charging system comprising:

• a vehicle driving battery mounted in a vehicle;
• an external power source external to the vehicle;
• an electric circuit switching unit connected to the external power source, the electric circuit switching unit having a first switching device and a switching control circuit that controls the first switching device;
• a vehicle charging apparatus connected to the electric circuit switching unit, the vehicle charging apparatus including
• a charging circuit connected to the first switching device,
• a charging control unit connected to a signal line of a pilot signal output from the switching control circuit so as to control the charging circuit,
• an external power supply enabling circuit connected to the signal line to change a potential of the signal line, and
• a power supply unit that supplies power to the charging control unit,
• the power supply unit being a capacitor charging circuit provided on a charging path that connects the signal line and the charging control unit, and the capacitor charging circuit supplies power to the charging control unit, and
• the capacitor charging circuit includes, in order from the signal line of the charging path, a first resistor, a first switch, a first diode arranged such that an anode is toward the first switch and a cathode is toward the charging control unit, and a capacitor;
• a DC/DC converter arranged between the charging circuit and the vehicle driving battery;
• a second switching device arranged between the DC/DC converter and the vehicle driving battery;
• and
• an auxiliary battery that is connected to the DC/DC converter and is a drive source for an in-vehicle device.