Vehicle-generator control device

• US 7,423,351 B2
• Filed: 10/10/2006
• Issued: 09/09/2008
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Maehara, Fuyuki
• Primary Examiner(s): Gonzalez; Julio
• Assistant Examiner(s): Cuevas; Pedro J
• Application Number:
  US11/544,707
• Publication Number:
  US 20070085512A1
• Time in Patent Office: 700 Days
• Field of Search: 290/40.C, 322/28
• US Class Current: 290/40.00C
• CPC Class Codes: H02J 7/243 with on/off action
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence

Abstract

The vehicle-generator control device for controlling an output voltage of a vehicle generator by on/off-controlling an excitation current flowing into an excitation winding of the vehicle generator, includes an excitation current detecting circuit detecting an excitation current flowing into the excitation winding, and a computation circuit having a first function of correcting the excitation current detected by the excitation current detecting circuit on the basis of a current flowing into an electrical load applied with the output voltage of the vehicle generator, and a second function of calculating an output current of the vehicle generator on the basis of the excitation current.

Claims

1. A vehicle-generator control device for controlling an output voltage of a vehicle generator by on/off-controlling an excitation current flowing into an excitation winding of said vehicle generator, comprising:

a first function of detecting said excitation current, a rotational speed of said vehicle generator, and an output voltage of said vehicle generator;

a second function of calculating an output current and a power generation torque of said vehicle generator on the basis of said excitation current, said rotational speed of said vehicle generator, and said output voltage of said vehicle generator detected by said first function;

a third function of limiting said excitation current to such a value that an increasing rate of said calculated power generation torque does not exceed a predetermined value;

a fourth function of detecting a current flowing into an electrical load applied with said output voltage of said vehicle generator; and

a fifth function of calculating, within a period during which an idle speed of said vehicle engine is stable, a correction coefficient of said excitation current on the basis of said output current of said vehicle generator and said current flowing into said electrical load, said second function being configured to correct said excitation current detected by said first function depending on said correction coefficient to improve calculation accuracy of said output current and said power generation torque of said vehicle generator.

2. The vehicle-generator control device according to claim 1, wherein said electric load is a vehicle battery charged by said vehicle generator, and said fifth function is configured to calculate said correction coefficient on the basis of a variation of a battery current of said vehicle battery when said excitation current is varied by a predetermined amount.

3. The vehicle-generator control device according to claim 2, wherein said fifth function is configured to calculate said correction coefficient on the basis of said variation of said battery current, and a variation of said output current calculated by said second function when said excitation current is varied by said predetermined amount.

4. The vehicle-generator control device according to claim 1, wherein a load current of said electrical load is known, and said fifth function is configured to calculate said correction coefficient on the basis of a variation of said output current calculated by said second function when said excitation current is varied by a predetermined amount, and said known load current of said electric load.

5. The vehicle-generator control device according to claim 1, wherein said correction coefficient calculated by said fifth function is stored in a nonvolatile memory included in said vehicle-generator control device.

6. The vehicle-generator control device according to claim 1, further comprising a sixth function of performing communication with outside to obtain a value of said current flowing into said electrical load and a value of said engine idle speed.

7. A vehicle-generator control device for controlling an output voltage of a vehicle generator by on/off-controlling an excitation current flowing into an excitation winding of said vehicle generator, comprising:

an excitation current detecting circuit detecting an excitation current flowing into said excitation winding; and

a computation circuit having a first function of correcting said excitation current detected by said excitation current detecting circuit on the basis of a current flowing into an electrical load applied with said output voltage of said vehicle generator, and a second function of calculating an output current of said vehicle generator on the basis of said excitation current,

wherein said electrical load is a vehicle battery charged by said vehicle generator, and said first function is configured to correct said excitation current detected by said excitation current detecting circuit on the basis of a variation of a battery current of said vehicle battery and a variation of said output current calculated by said second function when said excitation current is varied by a predetermined amount.