Electronic Control Apparatus

• US 20130090813A1
• Filed: 06/15/2011
• Published: 04/11/2013
• Est. Priority Date: 06/18/2010
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Kanekawa, Nobuyasu, Kobayashi, Ryoichi, Uehara, Atsushi, Koseki, Tomonobu, Honda, Keisuke
• Granted Patent: US 8,738,232 B2
• Time in Patent Office: Days
• US Class Current: 701/43
• CPC Class Codes: B60R 16/033 characterised by the use of electrical cells or batteries for propulsion puposes B60K1/04; supplying batteries to, or removing batteries from, vehicles B60S5/06; testing of charge state G01R31/36
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 5/0484 for reaction to failures, e.g. limp home
• CPC Class Codes: B62D 6/08 responsive only to driver input torque
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

An electronic control apparatus includes a control unit 2; a plurality of power supply units 1-1, 1-2 for supplying the control unit 2 with power; and a power supply fault detector unit 3 for detecting a fault in the plurality of power supply units 1-1, 1-2. The control unit 2 operates in a normal mode on electric power supplied from the plurality of power supply units 1-1, 1-2, when none of the plurality of power supply units 1-1, 1-2 is faulty. If at least one of the plurality of power supply units 1-1, 1-2 is faulty, the control unit 2 operates in an energy saving mode in which less power is consumed on electric power supplied from the power supply unit that remains fully operational. Thereby an electronic control apparatus is obtained that enables continued operation during a faulty condition, while preventing circuit scale, dimensions, weight, and cost from increasing.

Claims

1. An electronic control apparatus comprising:

a control unit;

a plurality of power supply units for supplying the control unit with power; and

a power supply fault detector unit for detecting a fault in the plurality of power supply units,

wherein the control unit operates in a normal mode on electric power supplied from the plurality of power supply units, when none of the plurality of power supply units is faulty; and

wherein if at least one of the plurality of power supply units is faulty, the control unit operates in an energy saving mode in which less power is consumed on electric power supplied from the power supply unit that remains fully operational.

2. The electronic control apparatus according to claim 1, wherein

the plurality of power supply units comprise a voltage regulator connected to a battery or a generator, the voltage regulator for supplying a predetermined voltage.

3. The electronic control apparatus according to claim 1,

wherein the control unit includes clock reduction means that reduces an operating clock frequency of a processor constituting the control unit in the energy saving mode.

4. The electronic control apparatus according to claim 3,

wherein the control unit includes parameter change means that changes a control parameter at the control unit in the energy saving mode.

5. The electronic control apparatus according to claim 1,

wherein the control unit includes a master control unit and a slave control unit, the master control unit being operated in the normal mode and the slave control unit being operated in the energy saving mode.

6. The electronic control apparatus according to claim 5,

wherein the slave control unit has a circuit scale smaller than that of the master control unit.

7. The electronic control apparatus according to claim 5,

wherein the slave control unit is configured with fixed logic circuitry.

8. The electronic control apparatus according to claim 5,

wherein the slave control unit is operated when a fault occurs in the master control unit with all of the plurality of power supply units remaining fully operational.

9. The electronic control apparatus according to claim 1,

wherein the plurality of power supply units are connected in parallel with each other, sharing an output current with each other.

10. The electronic control apparatus according to claim 1,

wherein the plurality of power supply units are connected in series with each other, sharing a voltage drop with each other.

11. An electric power steering control apparatus incorporating the electronic control apparatus according to claim 1,

wherein the control unit operates, having as inputs applied thereto an output from a torque sensor disposed on a shaft, an output from a rotation angle sensor disposed concentrically with a motor, and a value measured by a current sensor;

and

wherein a motor driven by the control unit applies steering torque to a steering wheel, a shaft, and a steering function.

12. An electric power steering system comprising:

a motor that applies a steering assist force to a steering system of an automobile;

a current sensor that detects motor current flowing through the motor;

a rotation angle sensor that detects a rotation angle of the motor;

a torque sensor that detects steering torque to be transmitted to the steering system;

a first control unit that controls the motor based on the motor current, the rotation angle, and the steering torque; and

a second control unit that, when a fault occurs in the first control unit, controls the motor based on the rotation angle and the steering torque in place of the first control unit.

13. The electric power steering system according to claim 12,

wherein the second control unit detects a steering effort on the steering system based on the rotation angle and the steering torque and outputs pulse width modulation current proportional to the steering effort thus detected to the motor.

14. The electric power steering system according to claim 12,

wherein the second control unit is configured with fixed logic circuitry including an analog circuit and a digital circuit.

15. The electric power steering system according to claim 12, wherein

the rotation angle sensor outputs a sin signal and a cos signal corresponding to the rotation angle;

and

the second control unit comprises;

a coordinate converter section that subjects the sin signal and the cos signal input from the rotation angle sensor to coordinate converter section into a three-phase sin signal;

a phase converter section that converts the three-phase sin signal that has undergone the coordinate converter section at the coordinate converter section to a corresponding digital phase signal;

a torque converter section that converts a torque signal input from the torque sensor to a corresponding digital torque signal; and

a multiplier section that multiplies the digital phase signal by the digital torque signal to thereby calculate a motor drive signal.

16. The electric power steering system according to claim 15,

wherein the coordinate converter section outputs three-phase sin signals having sin waveforms, each of which having a phase advancing 0, 2/3π

, and 4/3π

, respectively, from the sin signal.

17. The electric power steering system according to claim 15,

wherein the torque converter section converts the torque signal to a corresponding digital torque signal having a pulse width modulation waveform of a duty ratio that is proportional to a magnitude of the torque signal.

18. The electric power steering system according to claim 15,

wherein the phase converter section converts the three-phase sin signals to digital phase signals, each having any of three values of −

1, 0, and 1 determined according to a magnitude of waveforms of the three-phase sin signals.

19. The electric power steering system according to claim 15,

wherein the phase converter section outputs a 1 if the magnitude of the waveform of the three-phase sin signal is equal to, or greater than, a first threshold value, a −

1 if the magnitude of the waveform of the three-phase sin signal is equal to, or smaller than, a second threshold value, and a 0 if the magnitude of the waveform of the three-phase sin signal is smaller than the first threshold value and greater than the second threshold value.

20. The electric power steering system according to claim 19,

wherein the first threshold value is greater than the second threshold value.

21. The electric power steering system according to claim 15,

wherein the torque converter section converts the torque signal to a corresponding digital torque signal having a value of any of −

1, 0, and 1 determined according to a magnitude of the torque signal.

22. The electric power steering system according to claim 15,

wherein the torque converter section outputs a 1 if the magnitude of the torque signal is equal to, or greater than, a first threshold value, a −

1 if the magnitude of the torque signal is equal to, or smaller than, a second threshold value, and a 0 if the magnitude of the torque signal is smaller than the first threshold value and greater than the second threshold value.

23. The electric power steering system according to according to claim 22,

wherein the first threshold value is greater than the second threshold value.

24. The electric power steering system according to claim 15, wherein

the phase converter section outputs a digital phase signal having a pulse width modulation waveform of a duty ratio that is proportional to the magnitude of the waveform of the three-phase sin signal.

25. The electric power steering system according to claim 12, further comprising:

a fault detector unit that detects a fault of the first control unit; and

a selection changeover unit that selects control of the motor by the first control unit until the fault detector unit detects a fault and, when the fault detector unit detects a fault, selects control of the motor by the second control unit in place of the first control unit.