Bi-Directional Current Sensing Using Unipolar Sensors With Closed Loop Feedback

Patent metadata

Field	Value
Publication number	US-2016200213-A1
Application number	US-201514595269-A
Country	US
Kind code	A1
Filing date	Jan 13, 2015
Priority date	Jan 13, 2015
Publication date	Jul 14, 2016
Grant date	—

Abstract

A vehicle includes a ferromagnetic core having a winding, defining a gap, and configured to concentrate a net field in the gap. The vehicle also includes a controller programmed to flow a current in the winding such that an angle of the net field relative to a unipolar sensor in the gap is approximately zero and an intensity of the net field is at least twice that of a bi-directional field in the gap radiated from a conductor.

First claim

What is claimed is:

1 . A vehicle comprising:
a ferromagnetic core assembly defining a gap and having a winding configured to create a base magnetic field in the gap; a conductor coupling a traction battery with an electric machine configured to radiate a bi-directional magnetic field in the gap; a unipolar sensor, having a sensitivity range, located within the gap and configured to measure an intensity of a net magnetic field in the gap; and a controller programmed to flow a current in the winding to drive an angle of the net magnetic field towards zero such that an intensity of the net magnetic field falls within the sensitivity range, wherein a magnitude of the current is proportional to a torque of the electric machine and a polarity of the current is indicative of a direction of traction battery current flow.

2 . The vehicle of claim 1 , wherein the unipolar sensor is a giant magnetoresistance (GMR) sensor.

3 . The vehicle of claim 1 , wherein the net magnetic field in the gap is formed by the bi-directional magnetic field and the base magnetic field.

4 . The vehicle of claim 1 , wherein the bi-directional magnetic field is induced by a bi-directional current in the conductor.

5 . The vehicle of claim 1 further comprising a temperature sensor coupled to the unipolar sensor, wherein the controller is further programmed to monitor a temperature of the sensor and adapt the current flowing in the winding based on the temperature and a temperature drift of the unipolar sensor.

6 . The vehicle of claim 1 further comprising a second ferromagnetic core assembly, having a second gap, and a second unipolar sensor located within the second gap configured to measure an ambient magnetic field generated by an electric system in the vehicle.

7 . The vehicle of claim 6 , wherein the controller is further programmed to drive a current in the winding to compensate for the ambient magnetic field.

8 . The vehicle of claim 1 , wherein the ferromagnetic core assembly includes a toroid and the conductor passes through an axis of the toroid.

9 . A method of controlling a traction battery comprising:
outputting a current to a winding to induce a base magnetic field in a ferromagnetic core having a conductor passing through a center thereof; adjusting, via closed loop feedback, the current such that a net magnetic field is generally maintained within a sensitivity range of a unipolar sensor operatively arranged with the ferromagnetic core, wherein a lower threshold of the sensitivity range is greater than twice a maximum absolute value of a magnitude of an induced field from a bi-directional current expected to flow through the conductor; and operating the traction battery based on the current.

10 . The method of claim 9 , wherein the unipolar sensor is a giant magnetoresistance (GMR) sensor.

11 . The method of claim 9 further comprising monitoring a temperature of the sensor and adapting the current based on the temperature and a temperature drift of the unipolar sensor.

12 . The method of claim 9 further comprising measuring an ambient magnetic field generated by a vehicle electric system including the traction battery and further adjusting the current in the winding to compensate for the ambient magnetic field.

13 . A vehicle comprising:
a ferromagnetic core having a winding, defining a gap, and configured to concentrate a net field in the gap; and a controller programmed to flow a current in the winding such that an angle of the net field relative to a unipolar sensor in the gap is approximately zero and an intensity of the net field is at least twice that of a bi-directional field in the gap radiated from a conductor.

14 . The vehicle of claim 13 , wherein the net field in the gap is formed by the bi-directional field and a base field induced by the current in the winding.

15 . The vehicle of claim 13 , wherein the unipolar sensor is a giant magnetoresistance (GMR) sensor.

16 . The vehicle of claim 13 further comprising a temperature sensor coupled to the unipolar sensor, wherein the controller is further programmed to monitor a temperature of the sensor and adapt the current flowing in the winding based on the temperature and a temperature drift of the unipolar sensor.

17 . The vehicle of claim 13 further comprising a second ferromagnetic core assembly having a second gap, and a second unipolar sensor located within the second gap configured to measure an ambient field generated by an electric system in the vehicle.

18 . The vehicle of claim 17 , wherein the controller is further programmed to drive a current in the winding to compensate for the ambient field.

Assignees

• Ford Global Tech Llc

Inventors

• Wolf Christopher
• Degner Michael W

Classifications

• G01R15/205 Primary

  using magneto-resistance devices, e.g. field plates · CPC title

• B60W20/00

  Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)} · CPC title

• G01K13/00

  Thermometers specially adapted for specific purposes · CPC title

• B60L11/1864 Primary

  Operations & Transport · mapped topic

• Y10S903/907

  Electricity storage, e.g. battery, capacitor · CPC title