Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Variable speed controller with improved efficiency of energy transfer for an ac induction motor

Patent ·
OSTI ID:6439161

A variable speed controller for an alternating current induction motor reestablishes the start time for firing pulses and clock pulses in a circuit having a uniform frequency generator generating firing and clock pulses. Feedback from the stator terminals sets an oscillator with a sawtooth type ramp output. Subsequent feedback from the stator terminals are compared with the output of the oscillator in a comparator that establishes a time or phase shift in the generated output having the same frequency, for resetting the firing pulses so that the frequency of current to the stator winding is a function of the relationship between the stator and rotor positions, and of the current amplitude in the stator windings. Adjustment of the circuit parameters reduces the difference between the rotor and stator positions and optimizes stator current to maintain flux balance.

Assignee:
Hps Inc
Patent Number(s):
US 4366429
OSTI ID:
6439161
Country of Publication:
United States
Language:
English