Motor vehicle having an externally excited synchronous machine

Patent metadata

Field	Value
Publication number	US-12424963-B2
Application number	US-202318358863-A
Country	US
Kind code	B2
Filing date	Jul 25, 2023
Priority date	Jul 26, 2022
Publication date	Sep 23, 2025
Grant date	Sep 23, 2025

Abstract

A motor vehicle, having an externally excited synchronous machine and an inverter associated with the synchronous machine and connected to a high-voltage network and an exciter circuit associated with the synchronous machine to energize an exciter winding of the synchronous machine, comprising a power electronics layout having at least one intermediate circuit capacitor at the high-voltage network side, wherein the motor vehicle comprises a cooling device for cooling the power electronics layout and a voltage surge protection circuit is associated with the intermediate circuit capacitor, comprising at least one varistor, which becomes electrically conducting by the voltage imposed on it when a voltage threshold value is exceeded, wherein at least the one varistor of the voltage surge protection circuit forms part of an exciter module comprising the exciter circuit and a housing, which is thermally coupled to a cooling element of the cooling device for cooling the exciter module.

First claim

The invention claimed is:

1. A motor vehicle, comprising:
an externally excited synchronous machine;
an inverter associated with the synchronous machine and connected to a voltage network;
an exciter circuit which, in operation, energizes an exciter winding of the synchronous machine;
a power electronics layout having at least one intermediate circuit capacitor at a side of the voltage network;
a cooling device which, in operation, cools the power electronics layout; and
a voltage surge protection circuit associated with the at least one intermediate circuit capacitor and including at least one varistor which, in operation, becomes electrically conducting by a voltage imposed on the at least one varistor when a voltage threshold value is exceeded,
wherein the at least one varistor of the voltage surge protection circuit forms part of an exciter module including the exciter circuit and a housing,
wherein the housing is thermally coupled to a cooling element of the cooling device, and
wherein the at least one varistor includes at least two varistors switched in series in one varistor branch or in at least two parallel varistor branches each having at least one of the at least two varistors.

2. The motor vehicle according to claim 1 , wherein the at least one varistor, in operation, is switched in parallel with the at least one intermediate circuit capacitor.

3. The motor vehicle according to claim 1 , wherein the at least one intermediate circuit capacitor includes two intermediate circuit capacitors that, in operation, are switched in series along at least one capacitor branch of the power electronics layout, and for at least one varistor branch of the voltage surge protection circuit having the at least two varistors a first connection point situated between one of the two intermediate circuit capacitors of the at least one capacitor branch and a second connection point situated between the at least two varistors of the at least one varistor branch are connected across an electrical connection section.

4. The motor vehicle according to claim 1 , wherein at least one voltage value of the at least one varistor is such that the at least one varistor becomes electrically conducting upon reaching a defined critical value of an intermediate circuit voltage on the at least one intermediate circuit capacitor.

5. The motor vehicle according to claim 1 , wherein the exciter circuit is configured as a bridge circuit forming at least one half-bridge.

6. The motor vehicle according to claim 1 , wherein at least one part of the inverter is thermally connected to the cooling element of the cooling device.

7. The motor vehicle according to claim 6 , wherein the at least one part of the inverter includes at least one power module including a module housing.

8. A motor vehicle, comprising:
an externally excited synchronous machine;
an inverter associated with the synchronous machine and connected to a voltage network;
an exciter circuit which, in operation, energizes an exciter winding of the synchronous machine;
a power electronics layout having at least one intermediate circuit capacitor at a side of the voltage network;
a cooling device which, in operation, cools the power electronics layout; and
a voltage surge protection circuit associated with the at least one intermediate circuit capacitor and including at least one varistor which, in operation, becomes electrically conducting by a voltage imposed on the at least one varistor when a voltage threshold value is exceeded,
wherein the at least one varistor of the voltage surge protection circuit forms part of an exciter module including the exciter circuit and a housing,
wherein the housing is thermally coupled to a cooling element of the cooling device,
wherein at least one voltage value of the at least one varistor is such that the at least one varistor becomes electrically conducting upon reaching a defined critical value of an intermediate circuit voltage on the at least one intermediate circuit capacitor, and
wherein the defined critical value is greater than 800 volts.

9. The motor vehicle according to claim 8 , wherein the defined critical value is greater than 850 volts.

10. A motor vehicle, comprising:
an externally excited synchronous machine;
an inverter associated with the synchronous machine and connected to a voltage network;
an exciter circuit which, in operation, energizes an exciter winding of the synchronous machine;
a power electronics layout having at least one intermediate circuit capacitor at a side of the voltage network;
a cooling device which, in operation, cools the power electronics layout; and
a voltage surge protection circuit associated with the at least one intermediate circuit capacitor and including at least one varistor which, in operation, becomes electrically conducting by a voltage imposed on the at least one varistor when a voltage threshold value is exceeded,
wherein the at least one varistor of the voltage surge protection circuit forms part of an exciter module including the exciter circuit and a housing,
wherein the housing is thermally coupled to a cooling element of the cooling device,
wherein at least one voltage value of the at least one varistor is such that the at least one varistor becomes electrically conducting upon reaching a defined critical value of an intermediate circuit voltage on the at least one intermediate circuit capacitor, and
wherein the defined critical value is 1 to 3% greater than an operating voltage of the at least one intermediate circuit capacitor.

11. A motor vehicle, comprising:
an externally excited synchronous machine;
an inverter associated with the synchronous machine and connected to a voltage network;
an exciter circuit which, in operation, energizes an exciter winding of the synchronous machine;
a power electronics layout having at least one intermediate circuit capacitor at a side of the voltage network;
a cooling device which, in operation, cools the power electronics layout; and
a voltage surge protection circuit associated with the at least one intermediate circuit capacitor and including at least one varistor which, in operation, becomes electrically conducting by a voltage imposed on the at least one varistor when a voltage threshold value is exceeded,
wherein the at least one varistor of the voltage surge protection circuit forms part of an exciter module including the exciter circuit and a housing,
wherein the housing is thermally coupled to a cooling element of the cooling device,
wherein at least one voltage value of the at least one varistor is such that the at least one varistor becomes electrically conducting upon reaching a defined critical value of an intermediate circuit voltage on the at least one intermediate circuit capacitor, and
wherein the defined critical value is 5 to 15 volts greater than an operating voltage of the at least one intermediate circuit capacitor.

Assignees

• Audi Ag

Inventors

• Ruppert Daniel

Classifications

• H02K11/33

  Drive circuits, e.g. power electronics (H02K11/38 takes precedence) · CPC title

• H02P25/022

  Synchronous motors (H02P25/064 takes precedence) · CPC title

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• B60L50/60

  using power supplied by batteries (in combination with fuel cells B60L50/75) · CPC title

• H02M1/00

  Details of apparatus for conversion · CPC title