Induction machine with integrated magnetic gear and related methods

A method of determining the number of ring pieces and machine dimensions for an induction machine integrated with magnetic gear, comprising:

• e. providing operating conditions of a machine, wherein the operating conditions are selected from the required speed and torque,
• f. providing an induction machine with internal magnetic gear having two stators and two rotors, wherein the rotors include a high speed rotor and a low speed rotor,
• g. determining a combination of rotor bar numbers, pole pairs and permanent magnet pole pieces and a combination of modulating segments and number of permanent magnet pole pieces on the high speed roto and the low speed rotor are selected in accordance with an equation comprising:
• τ
• =
• p
• L
• 
• π
• 
• 
• rlgM
• H
• 
• ∏
• o
• 
• 
• M
• L
• 
• ∏
• 1
• 4
• 
• 
• μ
• o
• 
• sin
• 
• 
• p
• L
• 
• α
• .
• (
• 12
• )
• wherein r is the machine radius, l is the core length, g is the air gap length;
• p is the number of poles and co is the rotational speeds, subscripts “H” “L” and “S” denote high speed rotor and low speed rotor magnet pieces and modulating ring respectively;
• and
• h. incorporating the determined combinations into the two stators and two rotors.

A method of integrating an induction machine with a magnetic gear, comprising

• a. providing an induction machine with internal magnetic gear having two stators and two rotors, wherein the two rotors comprise a high speed rotor and a low speed rotor,
• b. determining the number of ring pieces and machine dimensions comprising the steps of:
• i. providing operating conditions of a machine, wherein the operating conditions are selected from the required speed and torque,
• ii. determining a combination of rotor bar numbers, pole pairs and permanent magnet pole pieces and a combination of modulating segments and number of permanent magnet pole pieces on the high speed roto and the low speed rotor are selected in accordance with an equation comprising:
• τ
• =
• p
• L
• 
• π
• 
• 
• rlgM
• H
• 
• ∏
• o
• 
• 
• M
• L
• 
• ∏
• 1
• 4
• 
• 
• μ
• o
• 
• sin
• 
• 
• p
• L
• 
• α
• .
• (
• 12
• )
• wherein r is the machine radius, l is the core length, g is the air gap length;
• p is the number of poles and co is the rotational speeds, subscripts “H” “L” and “S” denote high speed rotor and low speed rotor magnet pieces and modulating ring respectively;
• c. incorporating the determined combinations into the two stators and two rotors;
• and
• d. integrating the induction machine with the magnetic gears to achieve the desired operating conditions.

An induction machine with integrated magnetic gears, comprising:

• i) an outer stator defining stator slots and having a plurality of pole pairs, the outer stator comprising AC windings located in the stator slots, the AC windings being operationally connected to a power supply operating at a supply frequency, the outer stator for producing a rotating magnetic field synchronized with the supply frequency;
• ii) a high speed rotor positioned within the outer stator, the high speed rotor comprising a combination of rotor bars and permanent magnet pole pieces, the combination of rotor bars, pole pairs and permanent magnet pole pieces being configured for the permanent magnet pole pieces to not interact with the outer stator magnetic field, a rotation of the high speed rotor being asynchronously coupled to the outer stator rotating magnetic field, the high speed rotor generating a magnetic field;
• iii) an inner stator with ferromagnetic steel segments that modulate the magnetic field produced by the high speed rotor permanent magnets;
• and
• iv) a low speed inner rotor comprising other permanent magnet pole pieces, the low speed inner rotor being configured to counter rotate with respect to the high speed rotor,
• the outer stator, the high speed rotor and the low speed inner rotor each comprising a respective ferromagnetic material,
• the high speed rotor, low speed inner rotor, outer stator and inner stator being arranged concentrically about a shaft;
• the low speed inner rotor being synchronously coupled to the high speed rotor using modulation harmonics;
• and
• the combination of the ferromagnetic segments, the permanent magnet pole pieces of the high speed rotor and the other permanent pole pieces on the low speed inner rotor providing a magnetic gearing between the high speed rotor and the low speed rotor.

A method of determining the number of ring pieces and machine dimensions for an induction machine integrated with magnetic gears, the induction machine having two stators and two rotors, comprising the steps of:

• e. providing speed and torque operating conditions for an induction machine integrated with magnetic gears;
• and,
• f. determining operational parameters for the two stators and two rotors in accordance with an equation comprising:
• τ
• =
• p
• L
• 
• π
• 
• 
• rlgM
• H
• 
• ∏
• o
• 
• 
• M
• L
• 
• ∏
• 1
• 4
• 
• 
• μ
• o
• 
• sin
• 
• 
• p
• L
• 
• α
• .
• wherein r is the machine radius, l is the core length, g is the air gap length, p is the number of permanent pole pieces and subscripts “H” “L” and “S” denote high speed rotor and low speed rotor magnet pieces and modulating ring respectively;
• wherein the operational parameters are a combination of rotor bar numbers, pole pairs and permanent magnet pole pieces, the other permanent pole pieces and the ferromagnetic steel segments;
• and,
• wherein the rotors include a high speed rotor and a low speed rotor.

A method of integrating an induction machine with magnetic gears, the induction machine having two stators and two rotors, comprising the steps of:

• c. determining the number of ring pieces and machine dimensions comprising:
• i. providing speed and torque operating conditions for an induction machine integrated with magnetic gear;
• and,
• ii. determining operational parameters for the two stators and two rotors in accordance with an equation comprising:
• τ
• =
• p
• L
• 
• π
• 
• 
• rlgM
• H
• 
• ∏
• o
• 
• 
• M
• L
• 
• ∏
• 1
• 4
• 
• 
• μ
• o
• 
• sin
• 
• 
• p
• L
• 
• α
• .
• wherein r is the machine radius, l is the core length, g is the air gap length, p is the number of permanent pole pieces and subscripts “H” “L” and “S” denote high speed rotor and low speed rotor magnet pieces and modulating ring respectively and the operational parameters are a combination of rotor bar numbers, pole pairs and permanent magnet pole pieces, the other permanent pole pieces and the ferromagnetic steel segments;
• and,
• d. integrating the induction machine with the magnetic gears using the operational parameters;
• wherein the two rotors comprise a high speed rotor and a low speed rotor,