Electric machine with Q-offset grooved interior-magnet rotor and vehicle

• US 9,812,913 B2
• Filed: 02/18/2016
• Issued: 11/07/2017
• Est. Priority Date: 10/16/2008
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Saito, Yasuyuki, Goto, Tsuyoshi, Nakayama, Kenichi, Hino, Noriaki, Sugimoto, Shinji
• Primary Examiner(s): LE, DANG D
• Application Number:
  US15/046,813
• Publication Number:
  US 20160164354A1
• Time in Patent Office: 628 Days
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 15/025 using field orientation; Vector control; Direct Torque Control [DTC]
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/429 Current
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2270/142 acoustic
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: H02K 1/24 Rotor cores with salient poles ; Variable reluctance rotors
• CPC Class Codes: H02K 1/276 : Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/2766 : having a flux concentration effect
• CPC Class Codes: H02K 2201/06 : Magnetic cores, or permanent magnets characterised by their skew
• CPC Class Codes: H02K 2213/03 : Machines characterised by numerical values, ranges, mathematical expressions or similar information
• CPC Class Codes: H02K 29/03 : with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
• CPC Class Codes: H02K 7/006 : Structural association of a motor or generator with the drive train of a motor vehicle
• CPC Class Codes: H02P 27/06 : using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A rotating electric machine includes a stator having a stator coil and a rotor provided rotatably around a specific rotation axis with respect to the stator. The rotor includes a plurality of magnets, a plurality of magnetically-assisted salient pole members provided between poles of any adjacent two magnets from among the plurality of magnets, and a magnetoresistance variation unit provided in the magnetically-assisted salient pole member along an axial direction of the rotation axis at a position offset in a circumferential direction of the rotation axis from a q-axis passing through a salient pole center of the magnetically-assisted salient pole member. The amount of offset of the magnetoresistance variation unit from the q-axis varies depending on positions of the magnetically-assisted salient pole members so that torque fluctuations cancel each other when power is applied.

Claims

1. A rotor comprising:

a plurality of magnets;

a rotor core comprising a plurality of holes in which the magnets are provided;

wherein the plurality of magnets are arranged in regions of alternating polarity, wherein each of said regions has at least one magnet;

a plurality of magnetically-assisted salient pole members, each of which is provided in a core portion between the regions;

a first magnetic air gap formed with an edge of each of the magnets and the holes; and

a second magnetic air gap provided in each of the magnetically-assisted salient pole members along an axial direction of the rotation axis at a position offset in a circumferential direction of the rotation axis from a q-axis passing through a salient pole center of each of the magnetically-assisted salient pole members, wherein

the second magnetic air gap is formed independently from the first magnetic air gap;

the second magnetic air gap has an amount of offset from the q-axis in a cross section perpendicular to the rotation axis, the amount of offset varying depending on positions of the magnetically-assisted salient pole members so that torque fluctuations in the cross section cancel each other when power is applied; and

a magnet hole pole radian τ

g/τ

p is set from 0.5 to 0.9, wherein τ

p indicates pole pitch of the permanent magnet and τ

g indicates an angle for the magnet and the first magnetic air gaps on both sides thereof.

2. The rotor according to claim 1, wherein the magnet hole pole radian τ

g/τ

p is set from 0.7 to 0.8.

3. The rotor according to claim 1, wherein the second magnetic air gap is a groove provided on an outer periphery of the rotor core.

4. A rotating electrical machine comprising:

a stator having a stator coil; and

a rotor provided rotatably around a specific rotation axis with respect to the stator, wherein

the rotor includes;

a plurality of magnets;

a rotor core comprising a plurality of holes in which the magnets are provided;

wherein the plurality of magnets are arranged in regions of alternating polarity, wherein each of said regions has at least one magnet;

a plurality of magnetically-assisted salient pole members, each of which is provided in a core portion between the regions;

a first magnetic air gap formed with an edge of each of the magnets and the holes; and

a second magnetic air gap provided in each of the magnetically-assisted salient pole members along an axial direction of the rotation axis at a position offset in a circumferential direction of the rotation axis from a q-axis passing through a salient pole center of each of the magnetically-assisted salient pole members,

the second magnetic air gap is formed independently from the first magnetic air gap;

the second magnetic air gap has an amount of offset from the q-axis in a cross section perpendicular to the rotation axis, the amount of offset varying depending on positions of the magnetically-assisted salient pole members so that torque fluctuations in the cross section cancel each other when power is applied; and

a magnet hole pole radian τ

g/τ

p is set from 0.5 to 0.9, wherein τ

p indicates pole pitch of the permanent magnet and τ

g indicates an angle for the magnet and the first magnetic air gaps on both sides thereof.

5. The rotating electrical machine to claim 4, wherein the magnet hole pole radian τ

g/τ

p is set from 0.7 to 0.8.

6. The rotating electrical machine to claim 4, wherein the second magnetic air gap is a groove provided on an outer periphery of the rotor core.