# US 9,438,091 B2 · Permanent magnet machine with two stators

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- Number: US 9,438,091 B2
- Document ID: US9438091B2
- Status: Granted
- Kind: B2
- Application number: 13/224,477
- Filed: 2011-09-02
- Published: 2012-03-29
- Granted: 2016-09-06
- Earliest claimed: 2010-09-24
- Assignees: Siemens Aktiengesellschaft
- Applicants: Kenneth Pedersen
- Inventors: Kenneth Pedersen
- Web page: https://patentgrep.com/patent/US9438091B2

## CPC

- H02K 16/00: Machines with more than one rotor or stator {(machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029)}
- H02K 7/1838: {Generators mounted in a nacelle or similar structure of a horizontal axis wind turbine}
- H02K 16/04: Machines with one rotor and two stators
- H02K 29/03: with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
- Y02E 10/72: Wind turbines with rotation axis in wind direction
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A permanent magnet machine includes two stationary stators and a rotating rotor. Electromagnetic fields occurring in one stator are displaced by an angle of thirty electrical degrees with respect to electromagnetic fields occurring in the other stator due to currents fed to the stators.

## Claims

### Claim 1

A wind turbine generator, comprising:
a first stator and a second stator arranged next to each other in an axial direction on a ring shaped stator support structure connected to a main shaft, each of the first stator and second stator including a corresponding lamination stack and corresponding windings;
a rotor fixed to a rotor holding structure,
a first inverter and a second inverter, each of which connected to the respective windings of the first stator and the second stator,
wherein the first and second stators are arranged within the rotor holding structure,
wherein the rotor comprises permanent magnets mounted opposite to the lamination stacks of the first and second stators on the rotor holding structure, the permanent magnets having a length in the axial direction that corresponds to the added axial lengths of the two stators,
wherein electromagnetic fields occurring in the first stator are displaced by an angle of thirty electrical degrees with respect to electromagnetic fields occurring in the second stator, and
wherein currents fed by the first and second inverters to the respective windings of the first and second stators are displaced by thirty electrical degrees to each other.

### Claim 2 (depends on 1)

The wind turbine generator according to claim 1, wherein the first and second stators are displaced by an angle of thirty electrical degrees with respect to each other.

### Claim 3 (depends on 1)

A wind turbine, comprising:
a tower;
a main shaft connected to the tower;
a blade hub rotatively connected via a main bearing to the main shaft;
blades connected to the blade hub; and
a wind turbine generator according to claim 1 connected to the main shaft.

### Claim 4 (depends on 3)

The wind turbine according to claim 3, wherein the first and second stators are attached to the main shaft, and wherein the rotor is attached to the blade hub.