Abstract: An electronic motor drive for powering permanent magnet air core synchronous motors having sinusoidal back emf includes a switchmode power converter coupled to a connection of an input power supply. The power converter converts power from the input power supply with a current-mode control output and regulates current to a variable voltage link that supplies the regulated current to a non-modulating commutation inverter that energizes multi-phase air core armature windings of the air core motor. The motor drive employs 6-step position sensorless commutation exciting only two phase legs at a time controlled through measurement of the back emf. The switchmode power converter includes a low pass inductance and capacitance filter ahead of a power supply of the commutation inverter. The regulated current is switched at a regulation frequency high enough to preclude significant switching-induced harmonic ripple currents to the air core armature windings.

Abstract: A slotless rotating electric machine includes a rotor having multiple alternating polarity permanent magnets that drive magnetic flux across a magnetic airgap formed with a slotless ferromagnetic stator. The stator includes a helical backiron formed from a ferromagnetic strip wound edgewise and extending axially, and an adhesive film on the radial airgap surface of the backiron. Armature windings of wire having individually insulated twisted strands diametrically enveloped by an outer serve are adhered to the adhesive film. The adhesive film holds the said serve to the backiron and the serve holds the strands to the adhesive film. The armature windings pressed into the adhesive film as a group after they are formed and adhered while the adhesive cures, such that the wire is both bonded to the radial airgap surface of the helical stator backiron and is additionally partially embedded in the adhesive film.

Abstract: An electronic motor drive for powering permanent magnet air core synchronous motors having sinusoidal back emf includes a switchmode power converter coupled to a connection of an input power supply. The power converter converts power from the input power supply with a current-mode control output and regulates current to a variable voltage link that supplies the regulated current to a non-modulating commutation inverter that energizes multi-phase air core armature windings of the air core motor. The motor drive employs 6-step position sensorless commutation exciting only two phase legs at a time controlled through measurement of the back emf. The switchmode power converter includes a low pass inductance and capacitance filter ahead of a power supply of the commutation inverter. The regulated current is switched at a regulation frequency high enough to preclude significant switching-induced harmonic ripple currents to the air core armature windings.

Abstract: An electronic motor drive for powering permanent magnet air core synchronous motors having sinusoidal back emf includes a switchmode power converter coupled to a connection of an input power supply. The power converter converts power from the input power supply with a current-mode control output and regulates current to a variable voltage link that supplies the regulated current to a non-modulating commutation inverter that energizes multi-phase air core armature windings of the air core motor. The motor drive employs 6-step position sensorless commutation exciting only two phase legs at a time controlled through measurement of the back emf. The switchmode power converter includes a low pass inductance and capacitance filter ahead of a power supply of the commutation inverter. The regulated current is switched at a regulation frequency high enough to preclude significant switching-induced harmonic ripple currents to the air core armature windings.

Abstract: A slotless rotating electric machine includes a rotor having multiple alternating polarity permanent magnets that drive magnetic flux across a magnetic airgap formed with a slotless ferromagnetic stator. The stator includes a helical backiron formed from a ferromagnetic strip wound edgewise and extending axially, and an adhesive film on the radial airgap surface of the backiron. Armature windings of wire having individually insulated twisted strands diametrically enveloped by an outer serve are adhered to the adhesive film. The adhesive film holds the said serve to the backiron and the serve holds the strands to the adhesive film. The armature windings pressed into the adhesive film as a group after they are formed and adhered while the adhesive cures, such that the wire is both bonded to the radial airgap surface of the helical stator backiron and is additionally partially embedded in the adhesive film.

Abstract: An air core motor-generator has a rotor that is journalled to rotate about an axis of rotation, and a stator that is stationary and magnetically applies torque to the rotor. The rotor has magnetic poles that drive magnetic flux across an armature airgap, and the stator has an air core armature located in the armature airgap. Windings on the armature cause AC voltage to be induced in the windings as the rotor rotates. The windings include active length portions that are located in the armature airgap to receive the magnetic flux and induce the AC voltage, and end turn portions that traverse circumferentially and connect together the active length portions. The magnetic poles have a circumferential pole pitch, Y, and the active length portions of the windings having an active length circumferential width of a single phase, X, such that 0.5 Y<X<Y.