Charge controller for vehicle

1. A charge controller for a vehicle equipped with a rotating machine, a main battery having a first maximum storage capacity for storing electrical power supplied to the rotating machine, a power storage device having a second maximum storage capacity smaller than the first maximum storage capacity, and a solar power generator, the charge controller comprising:

a power converter interposed between the solar power generator and the power storage device;

a first charging section configured to control the power converter to store electrical power generated by the solar power generator in the power storage device;

a step-up section configured to step up and output the power stored in the power storage device to the main battery;

a second charging section configured to control the step-up section to charge the main battery with the power stored in the power storage device;

while the first charging section stores the power generated by the solar power generator in the power storage device, the second charging section controls the step-up section to step up the sum of:

the power stored in the power storage device, and

an output power of the power converter; and

the power stored in the power storage device and the output power of the power converter being inputted to the step-up section;

the power storage device is charged without powering ON an electronic device to monitor a state of charge of the power storage device; and

a control section, which acts as the second charging section, is periodically powered ON and performs a charging process to charge the main battery based on a terminal voltage of the power storage device.

2. The charge controller according to claim 1 , wherein

when the vehicle is parked, the second charging section charges the main battery with the power stored in the power storage device by powering ON a second number of electronic devices mounted on the vehicle,

when the vehicle is parked, the first charging section stores the power generated by the solar power generator in the power storage device by powering ON a first number of the electronic devices, and

the first number is smaller than the second number so that power consumption is smaller when the first charging section stores the power generated by the solar power generator in the power storage device than when the second charging section charges the main battery with the power stored in the power storage device.

3. The charge controller according to claim 1 , wherein

the first charging section includes a maximum power point tracking controller for performing a maximum power point tracking control by controlling the power converter,

the second charging section controls an output power of the step-up section to a command value, and

the command value is different from an output power of the power converter.

4. The charge controller according to claim 1 , wherein

the first charging section stores the power generated by the solar power generator in the power storage device regardless of a state of charge of the main battery.

5. The charge controller according to claim 1 , wherein

when the vehicle is parked, the second charging section charges the main battery with the power stored in the power storage device regardless of an output voltage of the solar power generator.

6. The charge controller according to claim 1 , wherein

the power converter maintains an electric current inputted from the solar power generator above zero during a period of time when the power converter outputs an electric current to the power storage device.

7. The charge controller according to claim 1 , wherein

the power storage device is an auxiliary battery.

8. The charge controller according to claim 1 , wherein

when the vehicle is parked, the second charging section is periodically powered ON, and

each time the second charging section is periodically powered ON, the second charging section detects the amount of the power stored in the power storage device, and

when the amount of the power stored in the power storage device is equal to or greater than a predetermined reference value, the second charging section charges the main battery with the power stored in the power storage device.

9. The charge controller according to claim 1 , wherein

the first charging section includes an integrator for calculating an integral value of a charging current to the power storage device, and

the second charging section charges the main battery with the power stored in the power storage device based on the integral value.

10. The charge controller according to claim 1 , further comprising:

a determining section configured to determine whether an output voltage of the solar power generator is equal to or greater than a predetermined reference voltage, wherein

when the determining section determines that the output voltage of the solar power generator is equal to or greater than the reference voltage, the first charging section starts to store the power generated by the solar power generator in the power storage device.

11. The charge controller according to claim 1 , further comprising:

a charger configured to be connected to an external power source to charge the main battery with power from the external power source, wherein

the charger includes a step-up circuit acting as the step-up section.

12. The charge controller according to claim 1 , wherein

the power storage device is an auxiliary battery, and

the step-up section is a bidirectional converter for exchanging power between the main battery and the auxiliary battery.

13. The charge controller according to claim 1 , further comprising:

a main charger configured to be connected to an external power source to charge the main battery with power from the external power source, and

an auxiliary charger configured to charge the power storage device with the power from the external power source, wherein

the power storage device is an auxiliary battery,

the main charger has an isolator for transmitting power between a primary side and a secondary side of the isolator by isolating the primary side and the secondary side,

the auxiliary charger has a function to step down and apply a voltage on the primary side to the auxiliary battery,

the first charging section includes a step-up circuit, a control section, and the auxiliary charger,

the step-up circuit steps up and apply an output voltage of the solar power generator to the auxiliary charger,

the control section electronically controls the step-up circuit and the auxiliary charger, and

the step-up section includes the main charger and the auxiliary charger.

14. The charge controller according to claim 1 , wherein

the second charging section stops charging the main battery with the power stored in the power storage device based on a terminal voltage of the power storage device.

15. The charge controller according to claim 1 , further comprising:

a switch configured to connect and disconnect the main battery to and from the step-up section, wherein

when an output power of the solar power generator is greater than a predetermined reference value, the switch keeps the main battery connected to the step-up section so that the main battery is charged with the power stored in the power storage device while the power generated by the solar power generator is stored in the power storage device.