Electric motor

Patent metadata

Field	Value
Publication number	US-2024421745-A1
Application number	US-202218701442-A
Country	US
Kind code	A1
Filing date	Oct 17, 2022
Priority date	Oct 20, 2021
Publication date	Dec 19, 2024
Grant date	—

Abstract

An electric motor is provided that includes a rotor, a stator, and a filter. The stator includes a stator core and windings. The filter is a magnetic low-pass filter including a coil having one or more turns and one or more capacitors connected in series with the coil. Excitation of the windings generates stator flux, the coil is linked to the stator flux, and the filter attenuates harmonics in the stator flux.

First claim

1 . An electric motor comprising:
a rotor; a stator comprising a stator core and windings; and a magnetic low-pass filter comprising a coil having one or more turns and one or more capacitors connected in series with the coil, wherein excitation of the windings generates stator flux, the coil is linked to the stator flux, and the filter attenuates harmonics in the stator flux.

2 . The electric motor as claimed in claim 1 , wherein the rotor comprises one or more magnets.

3 . The electric motor as claimed in claim 1 , wherein the filter has a resonant frequency greater than a running frequency of the motor.

4 . The electric motor as claimed in claim 3 , wherein the resonant frequency is at least twice that of the running frequency.

5 . The electric motor as claimed in claim 3 , wherein an impedance of the filter at the running frequency is at least ten times an impedance of the filter at the resonant frequency.

6 . The electric motor as claimed in claim 1 , wherein the filter has a resonant frequency less than a switching frequency of the motor.

7 . The electric motor as claimed in claim 6 , wherein an impedance of the filter at the switching frequency is no more than five times an impedance of the filter at the resonant frequency.

8 . The electric motor as claimed in claim 1 , wherein an impedance of the filter at a running frequency of the rotor is at least three times an impedance of the filter at a switching frequency of the windings.

9 . The electric motor as claimed in claim 1 , wherein the filter is mounted to the rotor.

10 . The electric motor as claimed in claim 1 , wherein the rotor comprises one or more magnets, and each magnet is segmented and comprises a plurality of magnet segments.

11 . The electric motor as claimed in claim 1 , wherein the rotor comprises one or more magnets, and the electric motor comprises a filter for each magnet.

12 . The electric motor as claimed in claim 11 , wherein the coil of the filter is wound about the magnet.

13 . The electric motor as claimed in claim 1 , wherein the capacitors are located within a cavity in one of the rotor and the stator.

14 . The electric motor as claimed in claim 13 , wherein the filter comprises a plurality of capacitors located along a length of the cavity.

15 . The electric motor as claimed in claim 1 , wherein the filter is passive.

Assignees

• Dyson Technology Ltd

Inventors

• Artacho López Adrián
• Smith Daniel James Bernard
• Mecrow Barrie Charles

Classifications

• H02P2207/05

  Synchronous machines, e.g. with permanent magnets or DC excitation · CPC title

• H02K11/028

  Suppressors associated with the rotor · CPC title

• H02K11/012

  Shields associated with rotating parts, e.g. rotor cores or rotary shafts · CPC title

• H02K1/223

  Rotor cores with windings and permanent magnets (for additional excitation in synchronous motors or generators H02K21/042; in synchronous motors having additional short-circuited winding for starting as an asynchronous motor H02K21/46) · CPC title

• H02K1/2773

  consisting of tangentially magnetized radial magnets · CPC title