Sensorless Multiscalar Control of Five-Phase Induction Machine with Inverter Output Filter

The paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback to linearize controlled system. The combination of flux harmonic distribution is implemented for five phase induction motor with concentrated stator windings in two reference frames alpha(1)beta(1)alpha(2)beta(2). Moreover, the speed sensorless drive operation was only possible with a dual observer structure for both reference frames. The nonlinear control structure and the observers are extended by LC filter model.