Vehicle controller, vehicle and vehicle control method

1. A controller for a vehicle including at least one motor driving wheels, an inverter driving said motor, and a boosting converter supplying a dc power supply current to said inverter, comprising

a control portion performing rectangular wave control and non-rectangular wave control on said inverter in a switched manner; wherein

said control portion has an emergency switching condition for switching control from said rectangular wave control to said non-rectangular wave control upon detection of a slip of a wheel, as a determination reference, and when said emergency switching condition is satisfied while said rectangular wave control is being executed, said control portion instructs said boosting converter to perform a process for preventing excessive voltage of said inverter.

2. The vehicle controller according to claim 1 , wherein

said control portion indicates a target voltage of boosting to said boosting converter, and said target voltage is lowered as the process for preventing excessive voltage of said inverter.

3. The vehicle controller according to claim 1 , wherein

said non-rectangular wave control is overmodulation PWM control or sinusoidal PWM control.

4. The vehicle controller according to claim 1 , wherein

said control portion determines whether said emergency switching condition is satisfied or not in accordance with a current flowing from said inverter to said motor.

5. The vehicle controller according to claim 4 , wherein

said control portion determines that said emergency switching condition is satisfied when a q-axis current supplied from said inverter to said motor exceeds a prescribed threshold value.

6. The vehicle controller according to claim 5 , wherein

said prescribed threshold value of said q-axis current is determined in advance in correspondence to an I-axis current supplied from said inverter to said motor.

7. The vehicle controller according to claim 1 , wherein

said vehicle further includes a multi-speed transmission for transmitting, with variable speed, driving force of said motor to an axle; and

said control portion changes an instruction to said boosting converter in accordance with the speed of said multi-speed transmission, when said emergency switching condition is satisfied.

8. A vehicle, comprising:

at least one motor driving wheels;

an inverter driving said motor;

a boosting converter supplying a dc power supply current to said inverter; and

a control portion performing rectangular wave control and non-rectangular wave control on said inverter in a switched manner; wherein

said control portion has an emergency switching condition for switching control from said rectangular wave control to said non-rectangular wave control upon detection of a slip of a wheel, as a determination reference, and when said emergency switching condition is satisfied while said rectangular wave control is being executed, said control portion instructs said boosting converter to perform a process for preventing excessive voltage of said inverter.

9. The vehicle according to claim 8 , wherein

said control portion indicates a target voltage of boosting to said boosting converter, and said target voltage is lowered as the process for preventing excessive voltage of said inverter.

10. The vehicle according to claim 8 , wherein

said non-rectangular wave control is overmodulation PWM control or sinusoidal PWM control.

11. The vehicle according to claim 8 , wherein

said control portion determines whether said emergency switching condition is satisfied or not in accordance with a current flowing from said inverter to said motor.

12. The vehicle according to claim 11 , wherein

said control portion determines that said emergency switching condition is satisfied when a q-axis current supplied from said inverter to said motor exceeds a prescribed threshold value.

13. The vehicle according to claim 12 , wherein

said prescribed threshold value of said q-axis current is determined in advance in correspondence to an I-axis current supplied from said inverter to said motor.

14. The vehicle according to claim 8 , further comprising

a multi-speed transmission for transmitting, with variable speed, driving force of said motor to an axle; wherein

said control portion changes an instruction to said boosting converter in accordance with the speed of said multi-speed transmission, when said emergency switching condition is satisfied.

15. A method of controlling a vehicle including at least one motor driving wheels, an inverter driving said motor, and a boosting converter supplying a dc power supply current to said inverter, comprising the steps of:

determining whether rectangular wave control is being executed on said inverter or not; and

instructing, when an emergency switching condition for switching control from said rectangular wave control to non-rectangular wave control is satisfied upon detection of a slip of a wheel, while said rectangular wave control is being executed, said boosting converter to perform a process for preventing excessive voltage of said inverter.

16. The method of controlling a vehicle according to claim 15 , wherein

said vehicle further includes a multi-speed transmission for transmitting, with variable speed, driving force of said motor to an axle;

said control method further comprising the step of

changing an instruction to said boosting converter in accordance with the speed of said multi-speed transmission, when said emergency switching condition is satisfied.