HIGH POWER-DENSITY, HIGH BACK EMF PERMANENT MAGNET MACHINE AND METHOD OF MAKING SAME

• US 20170257050A1
• Filed: 05/19/2017
• Published: 09/07/2017
• Est. Priority Date: 11/19/2010
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: EL-Refaie, Ayman Mohamed Fawzi, King, Robert Dean
• Application Number:
  US15/600,086
• Publication Number:
  US 20170257050A1
• Time in Patent Office: Days
• CPC Class Codes: B60K 2006/264 with outer rotor and inner stator
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60L 2210/14 Boost converters
• CPC Class Codes: B60L 2210/42 Voltage source inverters
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H02P 25/024 controlled by supply frequency
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: H02P 6/14 Electronic commutators
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10S 903/906 Motor or generator
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

An electric drive system includes a permanent magnet machine having a rotor and a stator and a power converter electrically coupled to the permanent magnet machine and configured to convert a DC link voltage to an AC output voltage to drive the permanent magnet machine. The power converter includes a plurality of silicon carbide switching devices having a voltage rating that exceeds a peak line-to-line back electromotive force of the permanent magnet machine at a maximum speed of the permanent magnet machine.

Claims

1. An electric drive system comprising:

a DC link;

a permanent magnet machine comprising a rotor and a stator; and

a power converter coupled between the permanent magnet machine and the DC link, the power converter comprising a plurality of silicon carbide (SiC) switching devices having a voltage rating that exceeds a voltage of the DC link when the permanent magnet machine operates in an uncontrolled generation mode.

2. The electric drive system of claim 1 wherein the voltage rating of the plurality of SiC switching devices is at least three kV.

3. The electric drive system of claim 1 wherein the plurality of SiC switching devices comprise SiC MOSFETs.

4. The electric drive system of claim 1 further comprising:

a power source coupled to the DC link; and

a controller programmed to disconnect the power source from the DC link based on a detected line-to-line back emf of the permanent magnet machine.

5. The electric drive system of claim 1 further comprising:

a DC power source;

a bi-directional DC-to-DC power converter configured to boost an output voltage of the DC power source and supply the boosted output voltage to the DC link; and

an input filter capacitor coupled between a positive DC rail and a negative DC rail of the DC link.

6. The electric drive system of claim 1 wherein the power converter comprises a multi-phase power converter.

7. The electric drive system of claim 1 wherein the permanent magnet machine comprises a traction motor.

8. A vehicle drive system comprising:

an alternator; and

a power converter coupled to the alternator, the power converter comprising a plurality of gate driven silicon carbide (SiC) switching devices having a voltage rating that exceeds a peak line-to-line back electromotive force (emf) of the alternator.

9. The vehicle drive system of claim 8 wherein the peak line-to-line back emf of the alternator is defined at a maximum speed of the alternator.

10. The vehicle drive system of claim 8 further comprising a power source coupled to the to the power converter through a DC link.

11. The vehicle drive system of claim 10 further comprising at least contactor configured to disconnect the power source from the DC link.

12. The vehicle drive system of claim 11 wherein the at least one contactor comprises a first contactor positioned on a positive rail of the DC link and a second contactor positioned on a negative rail of the DC link.

13. The vehicle drive system of claim 10 further comprising a controller programmed to disconnect the power source from the DC link if a detected line-to-line back emf of the alternator is within a threshold percentage of the voltage rating of the power source.

14. The vehicle drive system of claim 10 wherein the power source is a DC power source.

15. The vehicle drive system of claim 14 further comprising a bi-directional DC-to-DC voltage converter coupled between the DC power source and the DC link.

16. The vehicle drive system of claim 8 wherein the alternator is coupled to a heat engine.

17. The vehicle drive system of claim 8 wherein the plurality of gate driven SiC switching devices comprise SiC MOSFETs.

18. A power converter for use in a drive system of a hybrid electric vehicle, the power converter comprising a plurality of silicon carbide (SiC) switching devices having a voltage rating of at least three kV.

19. The power converter of claim 18 wherein the SiC switching devices comprise SiC MOSFETs.

20. A power converter for use in a drive system of a hybrid electric vehicle, the power converter comprising a plurality of switching devices, each of the plurality of switching devices consisting of a silicon carbide (SiC) MOSFET and an anti-parallel diode.