A control strategy for stand-alone wound rotor induction machine

Abstract

A control strategy to regulate the frequency and voltage of a stand-alone wound rotor induction machine is presented. This strategy allows the machine to work as a generator in stand-alone systems (without grid connection) with variable rotor speed. A stator flux-oriented control is proposed using the rotor voltages as actuation variables. Two cascade control loops are used to regulate the stator flux and the rotor currents. A closed loop observer is designed to estimate the machine flux which is necessary to implement these control loops. The proposed control strategy is validated through simulations with satisfactory results.

Modeling and Control of DFIG Through Back-to-Back Five Levels Converters Based on Neuro-Fuzzy Controller

“…(25) (Forchetti et al 2007). By neglecting the harmonics generated by switching, machine and converter loss and considering voltage aligned with d-axis, and by using Eqs.…”

A fuzzy logic supervisor for active and reactive power control of a variable speed wind energy conversion system associated to a flywheel storage system

“…Usually, the DFIG control is ensured by a vector control of the rotor currents [9][10][11]. The maximum power point tracking (MPPT) is ensured by the converter 1 (Conv1) in the rotor side.…”

Stand-Alone DFIG FOC Sensitivity and Stability Under Mismatched Inductances

“…Stand-alone controls implement the integral of the set-point frequency as a reference angle for the stator flux linkage. Subsequently, the measured [10], [15] or estimated [13]- [14], [16]- [18] rotor position is subtracted from the flux angle to calculate the slip angle. Asymptotic field orientation along either stator flux [10]- [21] or voltage [22], [23] is then achieved in different ways.…”

“…Asymptotic field orientation along either stator flux [10]- [21] or voltage [22], [23] is then achieved in different ways. Closed-loop schemes [15]- [17] need stator flux estimation and at least one dedicated controller to force the q-axis flux component to zero directly. Flux estimation relies on different techniques such as stator EMF integration [14], state observers and flux-current relationships [15]- [17].…”

“…Closed-loop schemes [15]- [17] need stator flux estimation and at least one dedicated controller to force the q-axis flux component to zero directly. Flux estimation relies on different techniques such as stator EMF integration [14], state observers and flux-current relationships [15]- [17]. However, this adds complexity to the control layout and can potentially cause offset drift issues in the integrator or further sensitivity to parameter variation, especially when machine inductances are involved.…”