DRIVER CIRCUIT AND METHOD FOR SINGLE-PHASE AND THREE-PHASE INDUCTION MOTORS

摘要

A control circuit for an induction motor operates to determine whether the inductor motor is of the three-phase type or single-phase type. If three-phase, a variable frequency drive operation is implemented. If single-phase, a closed loop current control process is implemented. The closed loop current control process includes an operation by the control circuit to measure winding resistances and determine a turns ratio for the main and auxiliary motor windings. The turns ratio is used in the closed loop current control process to scale a measurement of current in the auxiliary winding for the purpose of generating the control voltage for the auxiliary winding. Phase of the current in the windings is further processed to generate a phase control signal.

主权项

1. A method for controlling an induction motor having a first motor terminal, a second motor terminal and a third motor terminal, comprising:
measuring resistances of motor windings between pairs of the first, second and third motor terminals; processing the measured resistances to determine whether the induction motor is three-phase induction motor or a single-phase induction motor; if the induction motor is determined to be a three-phase induction motor, then controlling the three-phase induction motor using a variable frequency drive process; and if the induction motor is determined to be a single-phase induction motor, then controlling the single-phase induction motor using a closed loop current control process.