Method and device for detecting a speed in a generator unit

Patent metadata

Field	Value
Publication number	US-10411625-B2
Application number	US-201615776962-A
Country	US
Kind code	B2
Filing date	Oct 28, 2016
Priority date	Nov 18, 2015
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A method for determining a speed (nG) of a generator unit which has an electric machine ( 100 ) with a rotor winding ( 110 ) and a stator winding ( 120 ) and a rectifier ( 130 ) connected thereto, via which rectifier the electric machine ( 100 ) is connected to an electrical system ( 150 ) of a motor vehicle, the speed (nG) being determined depending on the plot of an excitation current (IE) flowing through the rotor winding ( 110 ) of the electric machine ( 100 ). In particular, the speed is determined from a known relationship between the speed, the frequency of the excitation current, the number of pole pairs and optionally the number of phases when there is an error that leads to a constant phase voltage being output.

First claim

The invention claimed is:

1. A method for determining a speed of a generator unit which has an electric machine with a rotor winding and a stator winding and a rectifier connected thereto, via which rectifier the electric machine is connected to an electrical system of a motor vehicle, the method comprising:
determining the speed based on a plot of an excitation current flowing through the rotor winding of the electric machine.

2. The method according to claim 1 , wherein the speed is determined depending on the plot of the excitation current if an error is present in the generator unit.

3. The method according to claim 2 , wherein the speed is determined depending on a plot of a phase voltage if an error is not present in the generator unit.

4. The method according to claim 1 , wherein the speed is determined depending on the plot of the excitation current (IE) if the phase voltage is fixed to a constant value.

5. The method according to claim 4 , wherein the speed is determined depending on the value of the phase voltage.

6. The method according to claim 5 , wherein the speed is determined equal to a frequency of the excitation current divided by the number of pole pairs.

7. The method according to claim 5 , wherein the speed is determined equal to a frequency of the excitation current divided by the number of pole pairs multiplied by twice the phase number of the generator if the phase voltage lies between a high-side voltage level and a low-side voltage level of the vehicle electrical system.

8. The method according to claim 1 , wherein the speed is detected depending on an analysis of a frequency spectrum of the plot of the excitation current or depending on an edge detection in the plot of the excitation current.

9. The method according to claim 1 , wherein a start-up of the generator unit is initiated if it is detected that a frequency of the excitation current lies above a speed threshold.

10. The method according to claim 9 , wherein the generator unit is started in a secured operation if an oscillation of the excitation current is greater than a threshold value and the frequency of the excitation current lies above an emergency start frequency.

11. The method according to claim 9 , wherein the generator unit is started in a normal operation if an oscillation of the excitation current is smaller than a threshold value and the frequency of the excitation current lies above an emergency start frequency.

12. A generator controller for determining a speed of a generator unit which has an electric machine with a rotor winding and a stator winding and a rectifier connected thereto, via which rectifier the electric machine is connected to an electrical system of a motor vehicle, the generator controller configured to determining the speed based on a plot of an excitation current flowing through the rotor winding of the electric machine.

13. A machine-readable storage medium having a computer program, that when executed by a computer, cause the computer to
determine a speed of a generator unit, which has an electric machine with a rotor winding and a stator winding and a rectifier connected thereto, via which rectifier the electric machine is connected to an electrical system of a motor vehicle, based on a plot of an excitation current flowing through the rotor winding of the electric machine.

Assignees

• Bosch Gmbh Robert

Inventors

• Magini Fabio
• Mueller Manuel
• Wohlfarth Michael
• Riederer Miriam

Classifications

• H02P2203/09

  Motor speed determination based on the current and/or voltage without using a tachogenerator or a physical encoder · CPC title

• H02P29/0241

  the fault being an overvoltage · CPC title

• G01P3/48

  by measuring frequency of generated current or voltage {(in general G01R23/00)} · CPC title

• H02P9/006 Primary

  Means for protecting the generator by using control (control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10) · CPC title

• H02P2101/25

  for combustion engines · CPC title