초록 ▼

A brushless permanent magnet motor has a rotor constructed of spaced ferromagnetic backirons and a circumferential array of alternating polarity magnetic poles that drive magnetic flux back and forth across an armature air gap between the backirons. A stator includes an air core armature in the air

A brushless permanent magnet motor has a rotor constructed of spaced ferromagnetic backirons and a circumferential array of alternating polarity magnetic poles that drive magnetic flux back and forth across an armature air gap between the backirons. A stator includes an air core armature in the air gap with three-phase windings. An inverter includes a pulse-modulated semiconductor H-bridge that switches and regulates power to the three-phase windings to drive the rotor. Harmonic losses in the motor caused by ripple currents generated by the higher pulse switching frequency in electronic variable speed drives, due to the inherently lower inductance of air core motors, are substantially reduced by adding serial inductance between the motor and drive. The H-bridge is serially electrically connected to the three-phase armature windings through three inductors that employ a low cost powder core. Each of the inductors provides an inductance that is greater than twice the value of the leg inductance of the three-phase windings.

대표청구항 ▼

I claim: 1. A high efficiency combination motor and electronic variable speed drive comprising: a brushless permanent magnet motor that has a rotor and a stator, and an electronic drive inverter that drives said motor by providing synchronous AC power to said stator; said rotor comprising a ferroma

I claim: 1. A high efficiency combination motor and electronic variable speed drive comprising: a brushless permanent magnet motor that has a rotor and a stator, and an electronic drive inverter that drives said motor by providing synchronous AC power to said stator; said rotor comprising a ferromagnetic backiron and a circumferential array of alternating polarity magnetic poles on said backiron that drives magnetic flux back and forth across an armature air gap; said stator comprising an air core armature with three-phase windings comprised of bundled multiple individually insulated strand conductor wire, said windings are assembled together in a substantially non-ferromagnetic structure that is located in said armature air gap, whereby alternating magnetic flux from said alternating polarity magnetic poles passes through said windings as said rotor rotates; said inverter comprising a pulse modulated semiconductor H-bridge that switches and regulates power to said three-phase windings to accelerate said rotor; each of said three-phase armature windings is serially electrically connected to said H-bridge through one of three inductors respectively, said inductors having windings on a powder core, each said inductor providing an inductance that is at least twice the value of the leg inductance of said three-phase windings. 2. A high efficiency combination motor and electronic variable speed drive as described in claim 1 wherein: said inductors comprises windings that are wound around said powder core wherein said powder core is in the form of toroid. 3. A high efficiency combination motor and electronic variable speed drive as described in claim 2 wherein: said toroid is constructed of iron powder that is held together in an unsintered resin matrix. 4. A high efficiency combination motor and electronic variable speed drive as described in claim 1 wherein: said inductors adjust the full load peak value of ripple current to lie between ��th and 1/12th of the peak value of said synchronous AC power current. 5. A high efficiency combination motor and electronic variable speed drive as described in claim 4 wherein: said ripple current through said inductors from said H-bridge switching occurs at a frequency between 5 kHz and 50 kHz. 6. A high efficiency combination motor and electronic variable speed drive as described in claim 1 wherein: said inverter utilizes sensorless flux vector control to provide commutation of said synchronous AC power to said inductors and said air core armature. 7. A high efficiency combination motor and electronic variable speed drive comprising: a brushless permanent magnet motor that has a rotor and a stator, and an electronic drive inverter that drives said motor by providing synchronous AC power to said stator; said rotor comprising a ferromagnetic backiron and a circumferential array of alternating polarity magnetic poles on said rotating backiron that drives magnetic flux back and forth across an armature air gap; said stator comprising an air core armature with three-phase windings that are assembled together in a substantially non-ferromagnetic structure that is located in said armature air gap, whereby alternating magnetic flux from said alternating polarity magnetic poles passes through said windings as said rotor rotates; said inverter comprising a pulse modulated semiconductor H-bridge that switches and regulates power to said three-phase windings to accelerate said rotor; said H-bridge is serially electrically connected to said three-phase armature windings through use of three inductors with distributed gap cores, wherein said inductors increase the total efficiency of the combination motor and electronic variable speed drive by reducing the ripple current induced losses generated in said rotor, each said inductor providing an inductance that is at least twice the value of the leg inductance of said three-phase windings. 8. A high efficiency combination motor and electronic variable speed drive as described in claim 7 wherein: said inductors have windings that are wound around said powder core, wherein said powder core is in the form of toroid. 9. A high efficiency combination motor and electronic variable speed drive as described in claim 8 wherein: said toroid is constructed of iron powder that is held together in an unsintered polymer resin matrix. 10. A high efficiency combination motor and electronic variable speed drive as described in claim 7 wherein: said inductors adjust the full load peak value of ripple current to lie between ��th and 1/12th of the peak value of said synchronous AC power current. 11. A high efficiency combination motor and electronic variable speed drive as described in claim 10 wherein: said ripple current through said inductors from said H-bridge switching occurs at a frequency between 5 kHz and 50 kHz. 12. A high efficiency combination motor and electronic variable speed drive as described in claim 7 wherein: said inverter utilizes sensorless flux vector control to provide commutation of said synchronous AC power to said inductors and said air core armature. 13. A high efficiency combination motor and electronic variable speed drive as described in claim 7 wherein: said alternating polarity magnetic poles employ radial magnetizations and said windings traverse axially in said armature air gap, wherein said brushless permanent magnet motor operates with a radial armature air gap. 14. A high efficiency combination motor and electronic variable speed drive comprising: a brushless permanent magnet motor that has a rotor and a stator, and an electronic drive inverter that drives said motor by providing synchronous AC power to said stator; said rotor includes two spaced apart ferromagnetic rotor portions together defining therebetween an armature air gap, and a circumferential array of alternating polarity magnetic poles on said ferromagnetic rotor portions that drive magnetic flux back and forth across said armature air gap; said stator comprising an air core armature with three-phase windings comprised of bundled multiple individually insulated strand conductor wire, said windings are assembled together in a substantially non-ferromagnetic structure that is located in said armature air gap, whereby alternating magnetic flux from said alternating polarity magnetic poles passes through said windings as said rotor rotates; said inverter includes a pulse modulated semiconductor H-bridge that switches and regulates power to said three-phase windings to accelerate said rotor; said H-bridge is serially electrically connected to said three-phase armature windings through three inductors with windings on a powder core, each said inductor providing an inductance that is greater than the value of the leg inductance of said three-phase windings. 15. A high efficiency combination motor and electronic variable speed drive as described in claim 14 wherein: said inductors comprises windings that are wound around said powder core wherein said powder core is in the form of toroid. 16. A high efficiency combination motor and electronic variable speed drive as described in claim 15 wherein: said toroid is constructed of iron powder that is held together in an unsintered resin matrix. 17. A high efficiency combination motor and electronic variable speed drive as described in claim 14 wherein: said inductors adjust the full load peak value of ripple current to lie between ��th and 1/12th of the peak value of said synchronous AC power current. 18. A high efficiency combination motor and electronic variable speed drive as described in claim 17 wherein: said ripple current through said inductors from said H-bridge switching occurs at a frequency between 5 kHz and 50 kHz. 19. A high efficiency combination motor and electronic variable speed drive as described in claim 14 wherein: said inverter utilizes sensorless flux vector control to provide commutation of said synchronous AC power to said inductors and said air core armature. 20. A high efficiency combination motor and electronic variable speed drive as described in claim 14 wherein: said alternating polarity magnetic poles employ radial magnetizations and said windings traverse axially in said armature air gap, wherein said brushless permanent magnet motor operates with a radial armature air gap.