초록 ▼

A motor is reconnected to a motor drive by exciting the motor to induce a back EMF, determining a speed of rotation of the motor based on the induced back EMF induced, and reconnecting the motor drive to the motor based on the speed determined. In order to induce the back EMF, current which flows th

A motor is reconnected to a motor drive by exciting the motor to induce a back EMF, determining a speed of rotation of the motor based on the induced back EMF induced, and reconnecting the motor drive to the motor based on the speed determined. In order to induce the back EMF, current which flows through the motor is controlled using first and second regulators. The outputs of the first and second current regulators are separated from each other in phase by approximately 90.degree.. A positive feedback loop is established by using the output of one of the first and second regulators to generate an input for the other one of the first and second regulators. The positive feedback loop advantageously causes the back EMF to continually increase as the motor continues to be excited, or at least not decay so rapidly that the speed of the motor cannot be accurately determined. Additionally, to determine the speed of the motor, the back EMF may be measured by commanding a current at a current command input of a current regulator, and then examining the voltage command output of the current regulator. Because the voltage command output is determined by the current regulator (e.g., in firmware or in software), there is no requirement for additional hardware to perform the voltage measurement.

대표청구항 ▼

[ I claim:] [9.] A system comprising:an induction motor; anda motor drive, the motor drive being coupled to the induction motor, the motor drive including a control system which controls current through the motor, the control system includinga first current regulator which controls a first component

[ I claim:] [9.] A system comprising:an induction motor; anda motor drive, the motor drive being coupled to the induction motor, the motor drive including a control system which controls current through the motor, the control system includinga first current regulator which controls a first component of the current through the motor and the first current regulator having a voltage command output,a second current regulator which controls a second component of the current through the motor, the second current regulator having a current command input, and the first and second components being separated in phase by approximately 90.degree., anda positive feedback loop which connects the voltage command output of the first current regulator to the current command input of the second current regulator, the positive feedback loop exciting the motor to induce a back EMF when the motor drive is being reconnected to the motor.