초록 ▼

A microcomputer for use with an induction motor drive system processes machine drive system currents, voltages and speed to compute real time machine efficiency. From real time machine efficiency determinations, the microcomputer determines the optimum combination of machine slip frequency and machi

A microcomputer for use with an induction motor drive system processes machine drive system currents, voltages and speed to compute real time machine efficiency. From real time machine efficiency determinations, the microcomputer determines the optimum combination of machine slip frequency and machine air gap flux. The magnitude and frequency of machine stator current are regulated, responsive to the difference in magnitude between optimum machine air gap flux and actual machine air gap flux, and the difference in magnitude between optimum slip frequency and actual slip frequency, respectively, to assure machine steady state operation at maximum efficiency irrespective of machine load conditions.

대표청구항 ▼

A method of controlling an induction machine drive during steady state operation using a microcomputer having stored machine constants, the machine drive having an stator current control loop and a stator frequency control loop, said method comprising the steps of: (1) measuring induction machine sl

A method of controlling an induction machine drive during steady state operation using a microcomputer having stored machine constants, the machine drive having an stator current control loop and a stator frequency control loop, said method comprising the steps of: (1) measuring induction machine slip, torque and air gap flux; (2) determining machine stator copper loss, rotor copper loss and iron loss from measured variables and machine constants; (3) determining machine efficiency from machine losses and power input to the machine; (4) processing machine efficiency as a function of air gap flux to determine whether air gap flux should be increased or decreased to increase machine efficiency; (5) varying air gap flux by a predetermined amount in the direction determined in step 4; (6) varying frequency so that the previously determined torque is maintained; (7) commanding the new values of air gap flux and frequency in said stator current control loop and said stator frequency control loop, respectively; and (8) repeating steps 1-8.