Other

Abb Oy

Samuli J Heikkil&auml;

Kalyan P Gokhale

Douglas W Karraker

The direct torque control (DTC) principle is used to control the torque of a wound ring rotor slip induction machine, also known as a doubly fed or cascade machine, by utilizing a solid state inverter on the rotor side. In addition, the DTC principle is used to control the power factor at the stator terminals of the doubly fed machine to a desired level and also to perform the task of synchronization of stator voltage to the grid voltage. An integrated controller is used to implement these three functions.

Controller for a wound rotor slip ring induction machine

A method for a frequency converter, when the frequency converter controls a motor and operates torque-controlled partly or entirely in a field weakening region. The method comprises the steps of defining the direction of travel and sector of a stator flux vector ({overscore (&psgr;)} ) in the motor, predicting a torque estimate (T ) produced by a voltage vector of the output of the frequency converter at the end of the voltage vector when a voltage vector change occurs at the instant of prediction, comparing the predicted torque estimate (T ) with a reference torque (T ) of the frequency converter, and implementing the voltage vector change when the predicted torque estimate (T ) is smaller than the reference torque (T ) and the stator flux vector ({overscore (&psgr;)} ) is moving in a positive direction of travel or when the torque estimate (T ) is greater than the reference torque (T ) and the stator flux vector ({overscore (&psgr;)} ) is moving in a negative direction of travel.

Growing community of inventors

Helsinki, Finland

Samuli J Heikkilä

Growing community of inventors

Helsinki, Finland

Samuli J Heikkil&auml;

Samuli J Heikkilä