Double-stator PM machine with 3rd order current harmonic injection

Patent metadata

Field	Value
Publication number	US-11316463-B2
Application number	US-202016737691-A
Country	US
Kind code	B2
Filing date	Jan 8, 2020
Priority date	Jan 11, 2019
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

A double-stator PM machine having: an outer stator generating an outer electromagnetic field dependent on an outer three-phase supply current; an inner stator generating an inner electromagnetic field dependent on an inner three-phase supply current; a PM rotor rotated by the outer and inner electromagnetic fields between the outer and inner stators; and a control arrangement controlling the outer and inner supply currents. There is an electrical connection between neutral points of the outer and inner stators. The control arrangement is configured for controlling the outer and inner supply currents such that there is a relative angle shift of 30° between the outer and inner supply currents and such that a third order current harmonic component is circulated between the outer and inner stators.

First claim

The invention claimed is:

1. A double-stator PM machine comprising:
an outer stator having an outer three-phase winding on an outer core, configured to generate an outer electromagnetic field dependent on an outer three-phase supply current supplied to the outer stator;
an inner stator positioned concentrically inside of the outer stator, the inner stator having an inner three-phase winding on an inner core, configured to generate an inner electromagnetic field dependent on an inner three-phase supply current supplied to the inner stator;
a permanent magnet, PM, rotor configured to be rotated by the outer and inner electromagnetic fields in a gap formed between the outer and inner stators; and
a control arrangement configured to control the outer and inner supply currents, respectively;
wherein there is a relative mechanical shift corresponding to an electrical angle of 30° between the outer and inner stators;
wherein there is an electrical connection between a neutral point of the outer stator and a neutral point of the inner stator;
wherein the control arrangement is configured to control the outer and inner supply currents such that there is a relative angle shift of 30° between the outer and inner supply currents, corresponding to the relative mechanical shift, and such that a third order current harmonic component is circulated between the outer and inner stators; and
wherein the rotor is provided with outer permanent magnets facing the outer stator and inner permanent magnets facing the inner stator.

2. The machine of claim 1 , wherein the control arrangement comprises:
an outer power electronic converter configured to output the outer supply current based on outer voltage references; and
an inner power electronic converter configured to output the inner supply current based on inner voltage references.

3. The machine of claim 2 , wherein the control arrangement comprises a current controller configured to output the outer and inner voltage references based on at least one operation reference of the machine.

4. The machine of claim 3 , wherein the current controller comprises:
a master controller configured to output one of the outer and inner voltage references to the respective outer or inner power electronic converter and to output a component of the at least one operation reference for the other of the outer and inner voltage references to a slave controller,
the slave controller being configured to output the other of the outer and inner voltage references to the respective outer or inner power electronic converter based on the component of the at least one operation reference.

5. The machine of claim 2 , wherein paths of magnetic flux through the outer stator are in series with paths of magnetic flux through the inner stator.

6. The machine of claim 2 , wherein the control arrangement is further configured to control the outer and inner supply currents such that a fifth order current harmonic component is circulated between the outer and inner stators.

7. The machine of claim 1 , wherein paths of magnetic flux through the outer stator are in series with paths of magnetic flux through the inner stator.

8. The machine of claim 1 , wherein the control arrangement is further configured to control the outer and inner supply currents such that a fifth order current harmonic component is circulated between the outer and inner stators.

9. A method of controlling a double-stator PM machine, the machine comprising:
an outer stator having an outer three-phase winding on an outer core, generating an outer electromagnetic field dependent on an outer three-phase supply current supplied to the outer stator;
an inner stator having an inner three-phase winding on an inner core, positioned concentrically inside of the outer stator, generating an inner electromagnetic field dependent on an inner three-phase supply current supplied to the inner stator;
a permanent magnet, PM, rotor brought to rotate by the outer and inner electromagnetic fields in a gap formed between the outer and inner stators; and
a control arrangement controlling the outer and inner supply currents, respectively;
wherein there is a relative mechanical shift corresponding to an electrical angle of 30° between the outer and inner stators, and a corresponding relative angle shift between the outer and inner supply currents;
wherein there is an electrical connection between a neutral point of the outer stator and a neutral point of the inner stator;
wherein the rotor is provided with outer permanent magnets facing the outer stator and inner permanent magnets facing the inner stator;
the method including:
the control arrangement controlling the outer and inner supply currents such that a third order current harmonic component is circulated between the outer and inner stators.

10. The method of claim 9 , wherein the amplitude of the third order current harmonic component is within the range of 0.3-0.5 of the amplitude of a fundamental component of the outer and/or inner supply current.

11. A double-stator PM machine comprising:
an outer stator having an outer three-phase winding on an outer core, configured to generate an outer electromagnetic field dependent on an outer three-phase supply current supplied to the outer stator;
an inner stator positioned concentrically inside of the outer stator, the inner stator having an inner three-phase winding on an inner core, configured to generate an inner electromagnetic field dependent on an inner three-phase supply current supplied to the inner stator;
a permanent magnet, PM, rotor configured to be rotated by the outer and inner electromagnetic fields in a gap formed between the outer and inner stators; and
a control arrangement configured to control the outer and inner supply currents, respectively;
wherein there is a relative mechanical shift corresponding to an electrical angle of 30° between the outer and inner stators;
wherein there is an electrical connection between a neutral point of the outer stator and a neutral point of the inner stator;
wherein the control arrangement is configured to control the outer and inner supply currents such that there is a relative angle shift of 30° between the outer and inner supply currents, corresponding to the relative mechanical shift, and such that a third order current harmonic component is circulated between the outer and inner stators;
wherein the control arrangement includes:
an outer power electronic converter configured to output the outer supply current based on outer voltage references;
an inner power electronic converter configured to output the inner supply current based on inner voltage references; and
a current controller configured to output the outer and inner voltage references based on at least one operation reference of the machine;

wherein the current controller includes a master controller configured to output one of the outer and inner voltage references to the respective outer or inner power electronic converter and to output a component of the at least one operation reference for the other of the outer and inner voltage references to a slave controller, the slave controller being configured to output the other of the outer and inner voltage references to the respective outer or inner power electronic converter based on the component of the at least one operation reference.

12. The machine of claim 11 , wherein paths of magnetic flux through the outer stator are in series with paths of magnetic flux through the inner stator.

13. The machine of claim 11 , wherein the control arrangement is further configured to control the outer and inner supply currents

Assignees

• Abb Schweiz Ag

Inventors

• Beniakar Minos
• Peretti Luca
• Kakosimos Panagiotis

Classifications

• H02M7/5395

  by pulse-width modulation · CPC title

• H02K11/33

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

• H02M7/53871 Primary

  with automatic control of output voltage or current · CPC title

• H02M1/0067

  Converter structures employing plural converter units, other than for parallel operation of the units on a single load · CPC title

• H02P25/098

  Arrangements for reducing torque ripple · CPC title