Induction Motor PI Observer with Reduced-Order Integrating Unit

Abstract

This article presents an innovative induction motor state observer designed to reconstruct magnetic fluxes and the angular speed of an induction motor for speed sensorless control system applications such as field-oriented control (FOC). This observer is an intermediate solution between the proportional observer and the classical proportional-integral (PI) observer with respect to which the order of the integrating unit is reduced. Additional modifications of the observer’s structure have been implemented to ensure stability and to improve its functional properties. As a result, two versions of the observer structure were produced and experimentally tested using a sensorless FOC control system. Both structures resulted in correct control system operation for a wide range of angular speeds, including low speed ranges.

Normalized-Model Reference System for Parameter Estimation of Induction Motors

“…Normalized fixed gain (20) while ensuring its adaptive parameter tends to the systems parameter over time, i.e., Θ(t) → Θ.…”

“…Moreover, beyond variable speed drives, fault detection, diagnosis, and prognosis also require the knowledge of these parameters [17,18]. Furthermore, efficiency estimation for energy savings planning [19] and other techniques for supervising the IM operation conditions [20], benefit from this information. These requirements motivate the development of identification techniques for IM parameters.…”

“…In contrast, the base value does not, and the inverter impacts the results, as described in [27,28]. Moreover, algorithms for controlling FOC and DTC [16] are robust under this level of accuracy, similar to those for supervising operating conditions [17][18][19][20].…”

Induction Motor Field-Oriented Sensorless Control with Filter and Long Cable

“…The obtained model can be considered a linear system with a time-varying parameter ω, as shown in Equations ( 7)- (9). It should be noted that ω has a dynamic slower than the other states variables; hence, its value can be considered as a constant.…”

“…However, its dynamics are too slow to be used in a control algorithm. Moreover, it is also well known that an observer obtained using only the motor model is affected by a certain error caused by the uncertainty of the motor parameters, it is necessary to introduce a system observer as studied in [7][8][9]. In fact, the motor parameters are affected primarily by measurement errors and parameter variations, mainly as a function of the temperature, especially affecting the rotor resistance in the case of induction machines.…”