Reducing the parameter dependency of Encoderless Predictive Torque Control for reluctance machines

Abstract

Encoderless Predictive Torque Control without Signal Injection utilizes internal information of a predictive torque controller to obtain the angle of the rotor saliency. When applying this approach to the reluctance machine the circulation of the current caused by the rotation of the strong saliency needs to be compensated by a parameter dependent term. This paper presents a new technique for compensating the circulation without knowledge of machine parameters. As a result the encoderless control scheme is free of motor parameters and the Predictive Torque Controller gains robustness. The approach is derived mathematically for a reluctance machine and verified with measurement results.

Optimal switching time calculation in Predictive Torque Control

“…This is achieved by including the two filters approaches from [10] and [11] which have to be slightly modified in order to use them in the proposed variable switching time based scheme.…”

“…The estimation of the low frequent current progression Δi r LF from [10] is replaced by the estimation of the low frequent current derivative d dtî…”

“…As described in [10] the result is a low pass filter loop, that forces the prediction error e s prd to converge to zero, where the cut-off frequency can be adjusted by k 1 .…”

Continuous Control Set Nonlinear Model Predictive Control of Reluctance Synchronous Machines

“…high efficiency, reliability and compact design, RSMs are easy to manufacture and comparably cheap due to the absence of magnets. Moreover, their anisotropic magnetic path in the rotor, makes them particularly suitable for saliency-based encoderless control [29,30]. However, a major drawback of the RSM concerning control is its characteristic nonlinearity of the flux linkage, caused by magnetic saturation and cross-coupling effects in the rotor.…”

Robust sensorless predictive control of induction motors with sliding mode voltage model observer

“…Saliency based sensorless PTC method was used for the reluctance motor in [15]. The problem of parameter sensitivity was solved by means of the techniques based on the reluctance motor characteristic [16]. In [17][18][19], a sensorless predictive current control was used in the field oriented control (FOC) method.…”