Electric load apparatus, electric load controlling method and computer readable recording medium recording program for causing computer to execute control of electric load

1. An electric load apparatus, comprising:

a voltage converter performing voltage conversion between a first DC voltage being output from a DC power source and a second DC voltage having a different voltage level from a voltage level of said first DC voltage;

an electric load being driven based on said second DC voltage output from said voltage converter; and

a control circuit controlling a change amount of power in said electric load to be set in a range in which a voltage converting operation of said voltage converter can be maintained when said change amount of the power exceeds a limit value, wherein

said limit value is a value set based on said change amount of the power in said electric load, and said change amount does not cause said second DC voltage to be lower than said first DC voltage.

2. The electric load apparatus according to claim 1 , wherein

the power in said electric load is consumed power in said electric load, and

said control circuit controls an increase amount of said consumed power to be at most as large as an allowable power that can be supplied to said electric load, when said increase amount of the consumed power exceeds said allowable power.

3. The electric load apparatus according to claim 2 , wherein

said control circuit limits said consumed power.

4. The electric load apparatus according to claim 1 , wherein

the power in said electric load includes generated electricity power in said electric load,

said control circuit decreases a voltage instruction value of said second DC voltage to control said voltage converter when an increase amount of the generated electricity power supplied from said electric load to said voltage converter exceeds a maximum value of response of said voltage converter.

5. The electric load apparatus according to claim 4 , wherein

said voltage converter includes

first and second switching elements for an upper arm and a lower arm, and

first and second flywheel diodes respectively connected to said first and second switching elements.

6. The electric load apparatus according to claim 2 , wherein

said control circuit increases said allowable power to control said consumed power to be at most as large as said allowable power.

7. The electric load apparatus according to claim 6 , wherein

said control circuit increases a voltage instruction value of said second DC voltage to control said voltage converter.

8. The electric load apparatus according to claim 7 , wherein

said voltage converter includes

first and second switching elements for an upper arm and a lower arm, and

first and second flywheel diodes respectively connected to said first and second switching elements.

9. The electric load apparatus according to claim 2 , wherein

said electric load includes

a motor producing torque for driving a driving wheel of a vehicle, and

an inverter converting said second DC voltage to AC voltage to drive said motor in accordance with control from said control circuit.

10. The electric load apparatus according to claim 2 , further comprising a capacitor element arranged between said voltage converter and said electric load and storing DC power; wherein

said electric load includes

a first motor producing torque for driving a driving wheel of a vehicle,

a first inverter converting said second DC voltage supplied from said capacitor element to AC voltage to drive said first motor in accordance with control from said control circuit,

a second motor generating electricity by power from an engine of said vehicle, and

a second inverter connected in parallel with said first inverter, converting AC power generated by said second motor to DC power and supplying said DC power to said capacitor element in accordance with control from said control circuit.

11. The electric load apparatus according to claim 2 , further comprising a generator connected in parallel with said electric load, wherein

said control circuit controls said generator such that the generated electricity increases.

12. The electric load apparatus according to claim 11 , wherein

said voltage converter includes

first and second switching elements for an upper arm and a lower arm, and

first and second flywheel diodes respectively connected to said first and second switching elements.

13. The electric load apparatus according to claim 12 , wherein

said electric load includes

a motor producing torque for driving a driving wheel of a vehicle, and

an inverter converting said second DC voltage to AC voltage to drive said motor in accordance with control from said control circuit, wherein

said generator generates electricity by power from an engine of said vehicle.

14. The electric load apparatus according to claim 1 , wherein

the power in said electric load is generated electricity power in said electric load, and

said control circuit controls an increase amount of the generated electricity power to be supplied from said electric load to said voltage converter to be at most as large as a response maximum value of said voltage converter, when said increase amount of the generated electricity power exceeds said response maximum value.

15. The electric load apparatus according to claim 14 , wherein

said control circuit controls said voltage converter such that the voltage level of said second DC voltage decreases.

16. The electric load apparatus according to claim 15 , wherein

said voltage converter includes first and second switching elements for an upper arm and a lower arm, and

said control circuit increases a time in which said first switching element is turned on to drive said voltage converter.

17. The electric load apparatus according to claim 14 , wherein

said electric load includes

a motor producing torque for driving a driving wheel of a vehicle, and

an inverter converting said second DC voltage to AC voltage to drive said motor in accordance with control from said control circuit.

18. The electric load apparatus according to claim 14 , further comprising a capacitor element arranged between said voltage converter and said electric load and storing DC power, wherein

said electric load includes:

a first motor producing torque for driving a driving wheel of a vehicle;

a first inverter converting said second DC voltage supplied from said capacitor element to AC voltage to drive said first motor in accordance with control from said control circuit;

a second motor generating electricity by power from an engine of said vehicle; and

a second inverter connected in parallel with said first inverter, converting AC power generated by said second motor to DC power and supplying said DC power to said capacitor element in accordance with control from said control circuit.

19. The electric load apparatus according to claim 1 , wherein

the power in said electric load is one of consumed power and generated electricity power in said electric load, and

said control circuit controls

an increase amount of said consumed power to be at most as large as an allowable power that can be supplied to said electric load, when said increase amount of the consumed power exceeds said allowable power, and

an increase amount of said generated electricity power supplied from said electric load to said voltage converter to be at most as large as a response maximum value of said voltage converter, when said increase amount of the generated electricity power exceeds said response maximum value.

20. An electric load apparatus controlling method, said electric apparatus includes a voltage converter performing voltage conversion between a first DC voltage being output from a DC power source and a second DC voltage having a different voltage level from a voltage level of said first DC voltage and an electric load being driven based on said second DC voltage output from said voltage converter, said method comprising:

a first step of detecting a change amount of power in said electric load;

a second step of determining whether said detected change amount of power exceeds a limit value; and

a third step of controlling said change amount of power in said electric load to be set in a range in which a voltage converting operation of said voltage converter can be maintained, when said change amount of power exceeds said limit value, wherein

said limit value is a value set based on said change amount of the power in said electric load, and said change amount does not cause said second DC voltage to be lower than the said first DC voltage.

21. The electric load apparatus controlling method according to claim 20 , wherein

said first step detects an increase amount of a consumed power in said electric load,

said second step determines whether said increase amount of the consumed power exceeds an allowable power that can be supplied to said electric load, and

said third step controls said change amount of the consumed power to be at most as large as said allowable power, when said increase amount of the consumed power exceeds said allowable power.

22. The electric load apparatus controlling method according to claim 21 , wherein

said third step limits said consumed power.

23. The electric load apparatus controlling method according to claim 21 , wherein

said third step controls said voltage converter converting said first DC voltage being output from DC power source to said second DC voltage such that a voltage level of said second DC voltage being converted from said first DC voltage increases.

24. The electric load apparatus controlling method according to claim 21 , wherein

said third step controls a generator connected in parallel with said electric load such that generated electricity in said generator increases.

25. The electric load apparatus controlling method according to claim 20 , wherein

said first step detects an increase amount of generated electricity power in said electric load being supplied to said voltage converter converting said second DC voltage from said electric load to said first DC voltage having a voltage level different from a voltage level of said second DC voltage,

said second step determines whether said detected increase amount of the generated electricity power exceeds a response maximum value of said voltage converter, and

said third step controls said voltage converter such that said increase amount of the generated electricity power becomes at most as large as said response maximum value of said voltage converter, when said increase amount of the generated electricity power exceeds said response maximum value.

26. The electric load apparatus controlling method according to claim 25 , wherein

said third step controls said voltage converter such that the voltage level of said second DC voltage decreases.

27. The electric load apparatus controlling method according to claim 20 , wherein

said first step includes

a first sub-step of detecting an increase amount of a consumed power in said electric load, and

a second sub-step of detecting an increase amount of a generated electricity power in said electric load being supplied to said voltage converter converting said second DC voltage from said electric load to said first DC voltage having a voltage level different from a voltage level of said second DC voltage,

said second step includes

a third sub-step of determining whether said increase amount of the consumed power exceeds an allowable power that can be supplied to said electric load, and

a fourth sub-step of determining whether said detected increase amount of the generated electricity power exceeds a response maximum value of said voltage converter,

said third step includes

a fifth sub-step of controlling said change amount of said consumed power to be at most as large as said allowable power, when said increase amount of the consumed power exceeds said allowable power, and

a sixth sub-step of controlling said voltage converter such that said increase amount of the generated electricity power becomes at most as large as said response maximum value of said voltage converter, when said increase amount of the generated electricity power exceeds said response maximum value.

28. A computer readable recording medium recording a program for controlling an electric load apparatus, said electric load apparatus includes a voltage converter performing voltage conversion between a first DC voltage being output from a DC power source and a second DC voltage having a different voltage level from a voltage level of said first DC voltage and an electric load being driven based on said second DC voltage output from said voltage converter, said program causing a computer to execute:

a first step of detecting a change amount of power in an electric load; and

a second step of determining whether said detected change amount of power exceeds a limit value; and

a third step of controlling said change amount of power to be set in a range in which a voltage converting operation of said voltage converter can be maintained, when said change amount of power exceeds said limit value, wherein

said limit value is a value set based on said change amount of the power in said electric load, and said change amount does not cause said second DC voltage to be lower than said first DC voltage.

29. The computer readable recording medium recording the program for causing the computer to execute according to claim 28 , wherein

said first step detects an increase amount of consumed power in said electric load,

said second step determines whether said increase amount of the consumed power exceeds an allowable power that can be supplied to said electric load, and

said third step controls said change amount of the consumed power to be at most as large as said allowable power, when said increase amount of the consumed power exceeds said allowable power.

30. The computer readable recording medium recording the program for causing the computer to execute according to claim 29 , wherein

said third step limits said consumed power.

31. The computer readable recording medium recording the program for causing the computer to execute according to claim 29 , wherein

said third step controls said voltage converter converting said first DC voltage being output from DC power source to said second DC voltage such that a voltage level of said second DC voltage being converted from said first DC voltage increases.

32. The computer readable recording medium recording the program for causing the computer to execute according to claim 29 , wherein

said third step controls a generator connected in parallel with said electric load such that generated electricity in said generator increases.

33. The computer readable recording medium recording the program for causing the computer to execute according to claim 28 , wherein

said first step detects an increase amount of generated electricity power in said electric load being supplied to said voltage converter converting said first DC voltage from said electric load to said second DC voltage having a voltage level different from a voltage level of said first DC voltage,

said second step determines whether said detected increase amount of the generated electricity power exceeds a response maximum value of said voltage converter, and

said third step controls said voltage converter such that said increase amount of the generated electricity power becomes at most as large as said response maximum value of said voltage converter, when said increase amount of the generated electricity power exceeds said response maximum value.

34. The computer readable recording medium recording the program for causing the computer to execute according to claim 33 , wherein

said third step controls said voltage converter such that the voltage level of said first DC voltage decreases.

35. The computer readable recording medium recording the program for causing the computer to execute according to claim 28 , wherein

said first step includes

a first sub-step of detecting an increase amount of a consumed power in said electric load, and

a second sub-step of detecting an increase amount of a generated electricity power in said electric load being supplied to said voltage converter converting said second DC voltage from said electric load to said first DC voltage having a voltage level different from a voltage level of said second DC voltage,

said second step includes

a third sub-step of determining whether said increase amount of the consumed power exceeds an allowable power that can be supplied to said electric load, and

a fourth sub-step of determining whether said detected increase amount of the generated electricity power exceeds a response maximum value of said voltage converter,

said third step includes

a fifth sub-step of controlling said change amount of the consumed power to be at most as large as said allowable power, when said increase amount of the consumed power exceeds said allowable power, and

a sixth sub-step of controlling said voltage converter such that said increase amount of the generated electricity power becomes at most as large as said response maximum value of said voltage converter, when said increase amount of the generated electricity power exceeds said response maximum value.