Sensorless Self-Commissioning of Synchronous Reluctance Motors at Standstill Without Rotor Locking

Abstract

This paper proposes a standstill method for identification of the magnetic model of synchronous reluctance motors (SyRMs). The saturation and cross-saturation effects are properly taken into account. The motor is fed by an inverter with a short sequence of bipolar voltage pulses that are first applied on the rotor d-and q-axes separately and then simultaneously on both the axes. The stator flux linkages are computed by integrating the induced voltages. Using the current and flux samples, the parameters of an algebraic magnetic model are estimated by means of linear least squares. The proposed method is robust against errors in the stator resistance and inverter voltage, due to the high test voltages (of the order of the rated voltage). The fitted model matches very well with the reference saturation characteristics, measured using a constant-speed method, and enables extrapolation outside the sample range. The method was tested with a 2.2-kW SyRM, whose shaft was uncoupled from any mechanical load, which is the most demanding condition for this method. The proposed method can be used for automatic self-commissioning of sensorless SyRM drives at standstill.

Observers for Sensorless Synchronous Motor Drives: Framework for Design and Analysis

“…The gain matrix is normalized by dividing it by ψ a0 2 in order to simplify the following equations. The condition (27) …”

Optimal Torque Control of Saturated Synchronous Motors: Plug-and-Play Method

“…The structure of the equivalent circuit is based on the assumption that the MMFs of the d-axis current and of the PMs are in series. Under this assumption, an algebraic magnetic model [24], originally developed for SyRMs, can be extended to the PM synchronous machines as…”

“…For SyRMs, a standstill method for identification of the magnetic model is available [24]. This identification method needs only the measurements of the phase currents and the DC-bus voltage, while neither motion sensor nor AC-side voltage sensors are needed.…”

Optimal torque control of synchronous motor drives: Plug-and-play method

“…The d-axis is selected along the minimum inductance axis. For SyRMs, a self-identification method for the magnetic model in (6) is available [25].…”