Importance

Loading Importance Indicators...

Abstract

An apparatus and method for controlling a brushless direct current motor having a pulse width modulated variable frequency drive in a blower system so that the blower system provides a specific fluid flow. A start-up program causes the motor to ramp up to approximately a predetermined steady state speed. A required blower torque is calculated by operating on a table of blower constants, a selected flow rate and a motor speed which is read from a commutation Hall sensor in the motor. A developed motor torque is calculated by operating on a table of motor specific constants, a modulation index and the motor speed taken from the commutation Hall sensor. The calculated required blower torque is repeatedly compared with the calculated developed motor torque. The modulation index to the pulse width modulated variable frequency drive is modified to force the developed motor torque to converge with the required blower torque in a steady state.

Loading the Abstract Image...

First Claim