Sensorless variable speed single-phase induction motor drive system based on direct rotor flux orientation

Abstract

The single-phase induction motor (SPIM) is one of the electrical machines more used in the World, and can be found in several fractional and sub-fractional horsepower applications in houses, offices, shoppings, farms, and industries. The introduction of more sophisticated applications has required the use of variable speed drives for SPIM, where the adoption of sensorless techniques is the more reasonable option for speed control due to the low cost of this electrical machine. A proposal for sensorless variable speed SPIM drive based on direct rotor field orientation techniques is presented in this paper. None transformation is used in order to eliminate the asymmetry of the stator windings of the SPIM. The rotor speed is estimated from an flux observer, which is based on two independent linear feedback control systems. The speed and flux estimatives are used in two control loop based on PID regulators, which determine the voltages to be applied to the SPIM windings by a three-legs VSI inverter. Using computer simulations, two situations are considered in order to demonstrate the satisfactory performance of the proposed sensorless speed control for SPIM drives: variations on rotor speed reference and the application of mechanical load

High-Order Sliding Mode Block Control of Single-Phase Induction Motor

“…This idea was previous proposed for mechanical systems in [37] and, for the SPIM, was applied only in [38]. The designed observer in spite of the previously works (including the SPIM case [28]) ensures finite-time estimation error convergence in the presence of motor parameter variation. 2) A motor speed basic controller that is designed using the measured stator current and estimated rotor flux, and applying a combination of block control feedback linearization [39] and quasi-continuous SM [40] techniques, a sliding manifold on which the control tracking error is finite-time zero is formulated, as shown in [41].…”

“…Then, again the super-twisting SM algorithm for the basic control input and switching logic for the auxiliary input are proposed to ensure the designed sliding manifold be a finite-time attractive. Comparing with [28], the proposed control scheme considers practical constraints, improves the produced motor torque by controlling the rotor flux, and exhibits robustness of the closed-loop system avoiding the estimation of the load torque, and allowing to overcome an uncertainty due to the rotor resistance variations, improving the tracking accuracy. As a result, the designed controller adjusts the equivalent capacitance incrementing the SPIM electromagnetic torque during startup and improving its performance in steady-state reducing pair-electromagnetic pulsating.…”

“…For example, [28] and [30]- [32] proposed a decoupling control vector for SPIM and flux-oriented control, where it is important to remove the pair-electromagnetic pulsating and torque control. Nevertheless, there is not an auxiliary control for the switched capacitor, while in [33]- [35], it was considered the problem of controlling the capacitor only without any observer design.…”

“…Moreover, the proposed sliding function depends on the motor parameters, which in practice can vary. It can be noted that, for the SPIM, a flux observer, which uses a linear compensator in the form of real differentiator, has been designed in [28] for the nominal plant only, therefore, this observer is sensitive to motor model uncertainty and sensor noise due to using the real differentiator, moreover, stability analysis of the closedloop system, included the observer, was not carried on.…”