New integration algorithms for flux estimation of AC machines

Two new integration algorithms for motor flux estimation based on voltage model are proposed in this paper. The algorithms can effectively solve the problems associated with pure integrators. Integration error in a flux estimation system comprises a drift produced by the integrator, somehow related to an initial condition, and the drift produced by an error present in the back electromotive force for the measurement of voltages and currents. The first algorithm is based on the combination of two different time phasors. The second algorithm, in which a phase-shift network of time phasor and a rotator of space vector are used. The new integration algorithms not only completely eliminate the integration drift, but also realize errorless flux estimation in steady state. The performance of these algorithms is studied and verified through simulation.