# US 2014/0152219 A1 · Control device and method for determining the rotor angle of a synchronous machine

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- Number: US 2014/0152219 A1
- Document ID: US20140152219A1
- Status: Published application
- Kind: A1
- Application number: 14/096,666
- Filed: 2013-12-04
- Published: 2014-06-05
- Earliest claimed: 2012-12-05
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Armin Niederer; Gerhard Knecht; Sebastian Paulus; Michael Koerner
- Web page: https://patentgrep.com/patent/US20140152219A1

## CPC

- H02P 6/187: {using the star point voltage}
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

Determining the rotor angle of a synchronous machine. In one aspect, the invention provides a method that includes generating a multiplicity of pulse-width-modulated drive signals for the phases of an inverter feeding the synchronous machine depending on a voltage to be fed into the synchronous machine, and applying a first phase shift to one or more of the multiplicity of pulse-width-modulated drive signals, so that the duration of the switching states of the inverter is extended in order to generate a first switching pattern for the phases of the inverter. The method also includes applying a second phase shift to one or more of the multiplicity of pulse-width-modulated drive signals for generating a second switching pattern, selecting one or more of the first and second switching patterns, determining one or more of neutral point potentials at the neutral point of the synchronous machine, and calculating the rotor angle of the synchronous machine.

## Claims

### Claim 1

A method for determining the rotor angle of a synchronous machine, the method comprising:
generating a multiplicity of pulse-width-modulated drive signals for the phases of an inverter feeding the synchronous machine depending on a voltage to be fed into the synchronous machine;
applying a first phase shift to one or more of the multiplicity of pulse-width-modulated drive signals, with the result that the duration of the switching states of the inverter in which an active voltage phasor is output is extended in order to generate a first switching pattern for the phases of the inverter;
applying a second phase shift to one or more of the multiplicity of pulse-width-modulated drive signals for generating a second switching pattern for the phases of the inverter;
selecting one or more of the first and second switching patterns for driving the inverter;
determining one or more of neutral point potentials at the neutral point of the synchronous machine during driving of the inverter with the selected switching patterns; and
calculating the rotor angle of the synchronous machine depending on the determined neutral point potentials.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the synchronous machine comprises a salient-pole machine or a non-salient-pole machine.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the calculation of the rotor angle is performed depending on differences in determined neutral point potentials.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the first and second switching patterns are selected in alternating sequence for driving the inverter.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising the following steps:
applying a third phase shift to one or more of the multiplicity of pulse-width-modulated drive signals for generating a third switching pattern for the phases of the inverter; and
selecting one or more of the first, second and third switching patterns for driving the inverter.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the first, second and third switching patterns are selected in cyclic sequence for driving the inverter.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the first, second and third switching patterns are selected alternately with respect to the pulse-width-modulated drive signals for driving the inverter.

### Claim 8 (depends on 1)

A control device for determining the rotor angle of a synchronous machine, wherein the control device is designed to implement a method according to claim 1.

### Claim 9 (depends on 8)

An electric drive system, comprising:
a control device according to claim 8;
a synchronous machine which is coupled to the control device; and
an inverter, which is coupled to the control device and the synchronous machine and which is designed to provide a supply voltage for the synchronous machine, wherein the control device is designed to drive the inverter depending on the determined rotor angle.