Rotor and rotor circuit for an electric motor

Patent metadata

Field	Value
Publication number	US-11218064-B2
Application number	US-201916439056-A
Country	US
Kind code	B2
Filing date	Jun 12, 2019
Priority date	Dec 14, 2016
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A rotor for an electric motor includes an even number n of pole pairs arranged on a rotor body with rotor windings connected in series between two electrical connections to supply or conduct away current through the rotor windings. The series circuit has a first section including n/2 rotor windings arranged first in the series circuit, and a second section including n/2 rotor windings and arranged upstream of the second electrical connection. During application of a direct-current voltage between the two connections in each of the rotor windings of the first section, the radial component of the direct-current flow in the series circuit extends through the entire respective rotor winding, from an outer side to an inner side of the rotor winding, and in each of the rotor windings of the second section, in reverse, from an outer side to an inner side of the rotor winding.

First claim

What is claimed is:

1. A rotor for a separately excited synchronous motor, the rotor comprising:
a rotor body; and
an even number, n, of pole pairs arranged on the rotor body with one rotor winding, respectively, wherein the rotor windings of the pole pairs are connected in series as a series circuit between two electrical connections of the rotor used to supply or conduct away an electrical excitation current through the rotor windings;
wherein the series circuit has a first section comprising a first n/2 rotor windings, from a first of the two electrical connections, arranged first in the series circuit, and a second section comprising a second n/2 rotor windings arranged upstream of a second of the two electrical connections; and
wherein the rotor windings and the series circuit are designed in such a way that during application of a direct-current voltage between the two electrical connections in each of the rotor windings of the first section, a radial component of the direct-current flow present in the series circuit extends through an entire respective rotor winding, from an outer side to an inner side of the rotor winding, and in each of the rotor windings of the second section, in reverse, from an outer side to an inner side of the rotor winding.

2. The rotor according to claim 1 , wherein, within the series circuit, the first section and the second section are connected at a connection point in such a way that two rotor windings, which are directly successively connected via the connection point are each connected to the connection point from a winding section lying on the outer side of their respective winding.

3. The rotor according to claim 2 , wherein the rotor windings and the series circuit are designed to be symmetrical in such a way that a first electrical stray capacitance of the first section of the rotor body corresponds to a second electrical stray capacitance of the second section of the rotor body of the rotor.

4. The rotor according to claim 1 , wherein, within the series circuit, the first section and the second section are connected at a connection point in such a way that two rotor windings, which are directly successively connected via the connection point are each connected to the connection point from a winding section lying on the inner side of their respective winding.

5. The rotor according to claim 4 , wherein the rotor windings and the series circuit are designed to be symmetrical in such a way that a first electrical stray capacitance of the first section of the rotor body corresponds to a second electrical stray capacitance of the second section of the rotor body of the rotor.

6. The rotor according to claim 1 , wherein the rotor windings and the series circuit are designed to be symmetrical in such a way that a first electrical stray capacitance of the first section of the rotor body corresponds to a second electrical stray capacitance of the second section of the rotor body of the rotor.

7. The rotor according to claim 6 , wherein a difference between the first electrical stray capacitance of the first section and the second electrical stray capacitance of the second section of the rotor body is no more than 10% of a resulting stray capacitance of the series circuit of n rotor windings of the rotor body running between the connections of the rotor.

8. The rotor according to claim 7 , wherein the difference between the first electrical stray capacitance of the first section and the second electrical stray capacitance of the second section of the rotor body is no more than 5% of the resulting stray capacitance of the series circuit of n rotor windings of the rotor body running between the connections of the rotor.

9. The rotor according to claim 7 , wherein the difference between the first electrical stray capacitance of the first section and the second electrical stray capacitance of the second section of the rotor body is no more than 2% of the resulting stray capacitance of the series circuit of n rotor windings of the rotor body running between the connections of the rotor.

10. A rotor circuit for a separately excited synchronous motor, comprising:
a rotor comprising:
a rotor body; and
an even number, n, of pole pairs arranged on the rotor body with one rotor winding, respectively, wherein the rotor windings of the pole pairs are connected in series as a series circuit between two electrical connections of the rotor used to supply or conduct away an electrical excitation current through the rotor windings;
wherein the series circuit has a first section comprising a first n/2 rotor windings, from a first of the two electrical connections, arranged first in the series circuit, and a second section comprising a second n/2 rotor windings arranged upstream of a second of the two electrical connections; and
wherein the rotor windings and the series circuit are designed in such a way that during application of a direct-current voltage between the two electrical connections in each of the rotor windings of the first section, a radial component of the direct-current flow present in the series circuit extends through an entire respective rotor winding, from an outer side to an inner side of the rotor winding, and in each of the rotor windings of the second section, in reverse, from an outer side to an inner side of the rotor winding;

a first supply line for connecting a first pole of a direct-current supply to the first of the two electrical connections of the rotor and a second supply line for connecting a second opposing pole of the direct-current supply to the second of the two electrical connections of the rotor; and
a capacitive voltage divider connected at a first connection between the first supply line and the second supply line with a first Y-capacitor between the first supply line and an electrically conductive connection to the rotor body and a second Y-capacitor between the first connection and the second supply line.

11. The rotor circuit according to claim 10 , wherein the first supply line comprises a first controllable resistor, the second supply line comprises a second controllable resistor, and a freewheeling diode for the rotor windings is connected between the first controllable resistor and the second controllable resistor and in parallel to the connections of the rotor windings.

12. The rotor circuit according to claim 11 , furthermore comprising a controller programmed to control the controllable resistors with a PWM-modulated control signal.

13. A separately excited synchronous motor for an electrically driven vehicle, comprising:
a rotor comprising:
a rotor body; and
an even number, n, of pole pairs arranged on the rotor body with one rotor winding, respectively, wherein the rotor windings of the pole pairs are connected in series as a series circuit between two electrical connections of the rotor used to supply or conduct away an electrical excitation current through the rotor windings;
wherein the series circuit has a first section comprising a first n/2 rotor windings, from a first of the two electrical connections, arranged first in the series circuit, and a second section comprising a second n/2 rotor windings arranged upstream of a second of the two electrical connections; and
wherein the rotor windings and the series circuit are designed in such a way that during application of a direct-current voltage between the two electrical connections in each of the rotor windings of the first section, a radial component of the direct-current flow present in the series circuit extends through an entire respective rotor winding, from an outer side to an inner side of the rotor winding, and in each of the r

Assignees

• Bayerische Motoren Werke Ag

Inventors

• Herrmann Hubert

Classifications

• H02K3/18

  Windings for salient poles · CPC title

• H02K3/52

  Fastening salient pole windings or connections thereto · CPC title

• H02K11/40

  Structural association with grounding devices · CPC title

• H02K19/12 Primary

  characterised by the arrangement of exciting windings, e.g. for self-excitation, compounding or pole-changing · CPC title

• H02K11/02

  for suppression of electromagnetic interference · CPC title