Field detecting system for three=phase machine - produces voltages proportional to magnetic flux components using model circuit to simulate processes in machine

摘要

The system has a current model circuit (1) receiving voltages proportional to the stator current (i) and magnetisation current and a rotor-position signal. The model circuit simulates those events in the machine that convert the currents into flux components and thereby produces signals describing the flux components. The circuit output signals are passed to a zero-point controller that eliminates the dc component in the difference between the flux component determined at the ac voltage integrator and the output of the model for this component. The advantage lies in the system's functioning at high and low speeds and in having low phase and amplitude errors that are independent of the machine frequency.