Voltage controller for vehicle using averaged status signal

• US 8,138,730 B2
• Filed: 08/27/2008
• Issued: 03/20/2012
• Est. Priority Date: 08/29/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tsuzuki, Tomomi
• Primary Examiner(s): Leung, Quyen
• Assistant Examiner(s): Truong, Thomas
• Application Number:
  US12/230,311
• Publication Number:
  US 20090058372A1
• Time in Patent Office: 1,301 Days
• Field of Search: 290 40 A- 40 F, 322/18
• US Class Current: 322/44
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/305 controlling voltage H02P9/302 takes precedence
• 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

In a voltage controller for a vehicle, voltage controlling means controls an output voltage of a power generator mounted on the vehicle and a terminal voltage of a battery connected to the power generator, by controlling of a field current passing through a field winding of the power generator. This control is performed by operating switching means connected to the field winding so that the switching means is conducted intermittently. Signal generating means generates a power generator state signal by measuring a state of the power generator at predetermined measurement periods. Signal averaging means performs an exponentially weighted averaging of the power generator state signal. The signal averaging means executes the averaging within a predetermined averaging period and updates the averaging at every predetermined measurement period.

Claims

1. A voltage controller electrically connected to a power generator mounted on a vehicle, the power generator having a field winding electrically connected in series to a switching means and the power generator being connected to a battery, the voltage controller comprising:

a voltage controlling means for controlling an output voltage of the power generator and a terminal voltage of the battery by intermittently switching the switching means on and off to control an amount of field current flowing through the field winding to control the output voltage of the power generator and the terminal voltage of the battery;

a signal generating means for generating a power generator state signal by repeatedly measuring a state of the power generator at predetermined measurement periods; and

a signal averaging means for performing an exponentially weighted averaging of the power generator state signal generated by the signal generating means, wherein

the signal averaging means executes the weighted averaging within a predetermined averaging period and updates the weighted averaging at each of the predetermined measurement periods,

the signal generating means generates at least one of a duty ratio of the switching means that is conducted intermittently and a current value of the field current flowing to the field winding as the power generator state signal,

the switching means is intermittently conducted at a predetermined period, and

the signal generating means measures one of the duty ratio and the current value and generates the power generator state signal at the predetermined measurement period that is equal to the predetermined period of the switching means, regardless if the switching means is in operation.

2. The voltage controller for a vehicle according to claim 1, wherein

the signal averaging means changes the predetermined averaging period depending on a state of the power generator for the vehicle.

3. The voltage controller for a vehicle according to claim 1, wherein

the signal averaging means sets the predetermined averaging period to a period corresponding to a time constant of the field winding.

4. The voltage controller for a vehicle according to claim 1, wherein

when the power generator state signals generated by the signal generating means have a same value that continues for a predetermined amount of time or a predetermined number of consecutive times, the signal averaging means outputs power generator state signals in which the same value is continued, instead of the weighted averaged power generator state signal.

5. The voltage controller according to the claim 1, further comprising:

a communicating means for communicating to a vehicle-side controller by using a predetermined protocol enabling a bidirectional communication therebetween, wherein the communication means is adapted to transmit the weighted averaged power generator state signal averaged by the signal averaging means to the vehicle-side controller and receive a communication signal transmitted by the vehicle-side controller.

6. The voltage controller for a vehicle according to claim 5, wherein

the signal averaging means changes the predetermined averaging period depending on the communication signal transmitted from the vehicle-side controller.