Double stator permanent magnet machine with magnetic flux regulation

Patent metadata

Field	Value
Publication number	US-10483891-B2
Application number	US-201715400180-A
Country	US
Kind code	B2
Filing date	Jan 6, 2017
Priority date	Jan 6, 2017
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Embodiments herein relate to a permanent magnet (PM) dynamoelectric machine. The machine includes a drive shaft, a PM rotor assembly with multiple PMs arranged around a periphery of the rotor assembly, a first stator assembly including a stator yoke, having stator teeth mounted to the stator core with distal ends proximate the outer periphery of the rotor assembly separated by a first air gap and multiple stator coils mounted between the stator teeth. The machine also includes a second stator assembly including a stator yoke, having stator teeth mounted to the stator core with distal ends forming closed slots, proximate an inner periphery of the rotor assembly separated by a second air gap and at least one control coil, the a control coil wrapped about a saturable region of the stator teeth thereof, each saturable region is operable to divert magnetic flux of the PMs through the stator teeth.

First claim

The invention claimed is:

1. A permanent magnet (PM) dynamoelectric machine with directly controllable PM flux control comprising:
a drive shaft;
a PM rotor assembly with multiple PMs arranged annularly around an outer periphery of the PM rotor assembly;
a first stator assembly comprising a ferromagnetic stator yoke, a first plurality ferromagnetic stator teeth mounted to the stator core with distal ends proximate the outer axial periphery of the rotor assembly separated by a first air gap and a first plurality of stator coils mounted between the stator teeth of the first plurality of stator teeth; and
a second stator assembly comprising a second ferromagnetic stator yoke, a second plurality of ferromagnetic stator teeth mounted to the stator core with distal ends proximate an inner periphery of the rotor assembly separated by a second air gap and at least one control coil, the at least one control coil wrapped about a saturable region of each the second plurality of stator teeth;
wherein each saturable region of the second plurality of stator teeth is operable as a magnetic diverter to divert air gap magnetic flux (Φg) generated by the multiple PMs across the second air gap through the distal ends of the second plurality of stator teeth.

2. The machine of claim 1 , wherein application of a control current Ic to the at least one control coil at least partially magnetically saturates the saturable region for the second plurality of stator teeth to reduce shunting of air gap magnetic flux Φg, thereby controlling magnetic flux linkage Ψ M between the multiple PMs and the first plurality of stator coils.

3. The machine of claim 1 , wherein application of a control current I c to the at least one control coil at least partially magnetically saturates the saturable region for the second plurality of stator teeth to reduce shunting of air gap magnetic flux Φg, thereby at least one of increasing generated electromagnetic force (EMF) and increasing electromagnetic torque T c to desired levels upon application of electrical power to the stator coils at lower levels of rotor assembly angular velocity.

4. The machine of claim 1 , wherein the second stator assembly and the second plurality stator teeth have closed distal ends forming closed slots.

5. The machine of claim 1 , wherein the first stator assembly comprises at least one of a laminated ferromagnetic alloy construction and a ferromagnetic stamping.

6. The machine of claim 1 , wherein the second stator assembly comprises at least one of a laminated ferromagnetic alloy construction and a ferromagnetic stamping.

7. The machine of claim 1 , wherein the PM rotor assembly comprises at least one of a laminated ferromagnetic alloy construction, a sintered magnetic powder construction, a solid steel structure, and a ferromagnetic stamping.

8. The machine of claim 1 , wherein the multiple PMs extend from the outer periphery of the rotor assembly to the inner periphery of the PM rotor assembly.

9. The machine of claim 1 , wherein the multiple PMs are arranged in a radial direction and magnetized tangentially.

10. The machine of claim 1 , wherein the multiple PMs are arranged with ferromagnetic material of the PM rotor assembly between the multiple PMs, thereby forming magnetic poles in the ferromagnetic material.

11. The machine of claim 1 , wherein each saturable region between stator teeth of the second stator assembly exhibits high reluctance when saturated limiting magnetic flux linkage from the multiple PMs.

12. The machine of claim 1 , wherein the at least one control coil is a plurality of control coils connected in series.

13. The machine of claim 2 , wherein the control current Ic is direct current (DC).

14. The machine of claim 13 , wherein adjacent windings of the control coils attach to each other to shunt magnetic fluxes from the multiple PMs in opposition.

15. The machine of claim 13 , wherein the at least one control coil is a plurality of control coils and a first side of each of the plurality of control coils connects to a first side of a preceding adjacent one of the plurality of control coils in series and a second side of each of the plurality of control coils opposite the first side connects to the second side of the following adjacent control coil.

16. The machine of claim 1 , wherein the second air gap is smaller than the first air gap.

17. The machine of claim 1 , wherein the machine is configured and operable as at least one of a PM generator and a PM motor.

18. A permanent magnet (PM) electric generator system with directly controllable field excitation control comprising:
a prime mover;
a main PM generator coupled to the prime mover comprising a PM rotor assembly with multiple PMs arranged around an outer axial periphery of the rotor assembly, a first stator assembly comprising a ferromagnetic stator core, a first plurality of ferromagnetic stator teeth mounted to the stator with distal ends proximate the outer axial periphery of the rotor assembly separated by an air gap and multiple stator coils mounted between the stator teeth, of the first plurality of stator teeth; and a second stator assembly comprising a second ferromagnetic stator yoke, a second plurality of ferromagnetic stator teeth mounted to the stator core with distal ends proximate an inner periphery of the rotor assembly separated by a second air gap and at least one control coil, the at least one control coil wrapped about a saturable region of the second plurality of stator teeth; and wherein each saturable region of the second plurality of stator teeth is operable as a magnetic diverter to divert air gap magnetic flux Φg generated by the multiple PMs across the air gap through the distal ends of the second plurality of stator teeth;
a main power rectifier system for converting multiphase alternating current (AC) associated with stator coils to direct current (DC) main power on a DC power bus that feeds a DC load;
an auxiliary power source;
a control current regulator that regulates current from the auxiliary power source to produce control current for a control coil;
a main power voltage feedback loop that compares voltage on the DC power bus to a reference voltage and generates a reference control current signal representative of the difference; and
a control current feedback loop that compares the control current to the reference control current signal and generates a control current regulating signal representative of the difference that changes the control current produced by the control current regulator.

19. The system of claim 18 , wherein the auxiliary power source comprises a multiphase AC auxiliary machine driven by the prime mover and a multiphase AC rectifier that converts AC power generated by the multiphase AC auxiliary machine to DC power.

20. The system of claim 18 , further comprising a pulse width modulator (PWM) circuit that receives the control current regulating signal and generates corresponding PWM control signals.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Gieras Jacek F

Classifications

• H02K21/046

  with rotating permanent magnets and stationary field winding · CPC title

• H02K16/04 Primary

  Machines with one rotor and two stators · CPC title

• H02K21/12

  with stationary armatures and rotating magnets · CPC title

• H02P9/302

  Brushless excitation · CPC title

• H02P21/06

  Rotor flux based control involving the use of rotor position or rotor speed sensors · CPC title