Microchip Technology Inc.

Motor Patent Licensors, LLC

Howard Hendricks

Ward Brown

Thomas H Hopkins

Scott T Graham

Patrick J Stoever

Nicholas R Bries

Ward R Brown

Low cost linear Hall Effect sensors are used for determining motor shaft positions and generating voltages proportional to the motor shaft positions. The voltages from the linear Hall Effect sensors are compared to a triangle waveform and PWM signals are generated therefrom. A constant current source and constant current sink are used in the triangle waveform generator. The voltages from the linear Hall Effect sensors are adjusted to change the PWM duty cycles used to startup and vary the speed of the motor. Comparators compare the voltages from the Hall Effect sensors and product the PWM signals having duty cycles proportional to the voltage drive requirements of the motor.

Linear hall effect sensors for multi-phase permanent magnet motors with PWM drive

A pulse width modulated (PWM) trapezoidal commutation drive to a brushless direct current (BLDC) motor is sine modified so that the applied drive voltage substantially matches the induced voltage generated in the BLDC motor. The values of the cosine of the angles between &#x2212;30 degrees and +30 degrees are used to modify the duty cycle of the PWM drive signal dependent upon the rotor angular positions determined from the times between the zero crossing BEMF voltages measured at the unconnected motor terminals.

Sine modified trapezoidal drive for brushless DC motors

A radial flux permanent magnet AC motor/generator employs a flat circular stator plate having a plurality of separately-formed electromagnets mounted in a ring pattern on a top surface thereof. A circular flux ring fabricated of powdered metal is mounted to the stator plate outside the ring of electromagnets. A plurality of permanent magnets are mounted in a ring pattern on the outer cylindrical surface of a steel rotor. The stator plate and rotor are axially and diametrically aligned such that the ring of permanent magnets rotates in close proximity to and inside the ring of electromagnets. The electromagnets utilize powder metal cores shaped to have rounded corners and flat sides that permit the use of heavier gauge windings and eliminate the air gaps that exist between the core and windings of prior art electromagnets.

Radial flux permanent magnet AC motor/generator

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Prescott, AZ, United States of America

Howard Hendricks