Flux estimation algorithms for electric drives: A comparative study

Abstract

This paper reviews the stator flux estimation algorithms applied to the alternating current motor drives. The socalled voltage model estimation, which consists of integrating the back-electromotive force signal, is addressed. However, in practice, the pure integration is prone to drift problems due to noises, measurement error, stator resistance uncertainty and unknown initial conditions. This limitation becomes more restrictive at low speed operation. Several solutions, reported in the literature, are reviewed and compared. Emphasis is placed on the low-pass filter based algorithms that show good performance in steady-state as well as in transient operating conditions.

A Driftless Estimation of Orthogonal Magnetic Flux Linkages in Sensorless Electrical Drives

“…For qualitative comparisons of the proposed compensation with the state of the art, the standard solution with LPFs instead of the integrators presented in [5][6][7][8][9][10][11] was chosen as the first reference method, while the previous compensation introduced in [23] and presented by the diagram in Figure 9 was chosen as the second reference method.…”

“…Figure 13 are shown in Figure 14, from which it can be noticed that the proposed compensation preserves the dynamic of the previous compensation in [23] while having the filtering properties of LPFs, but without any undesirable influence on |λ s | and φ λ in steady states. obtained by the simulation of the standard solution with LPFs presented in [5][6][7][8][9][10][11], the previous compensation presented in [23], and the proposed compensation, all with the noisy test signals.…”

“…The same effect can be achieved with a high-pass filter (HPF) in a cascade with each of the integrators. Such solutions with the fixed cut-off frequencies of the filters affect both the magnitude and the phase of the output waveforms of the magnetic flux linkages, as it can be seen from the results presented in [5][6][7][8][9][10][11]. The influence of the cut-off frequency on the magnitude for the frequencies more than two octaves above it is practically negligible, while the influence on the phase can be considered negligible for the frequencies more than two decades above the cut-off frequency.…”

“…The solutions in [21,22] are fundamentally identical and have good dynamics, but the downside is the requirement of the reference value of the magnitude of the resulting magnetic flux linkage. A solution based on orthogonal properties of the waveforms of input voltages and resulting magnetic flux linkages in the frame of reference fixed to the geometry of the stator is presented in [23], where from the presented results of simulations and experiments it can be seen that the settling times, and therefore the dynamics, are exceptionally good.According to the results of the comparative simulations presented in [23] of the solution proposed in [23] with the solutions from [5][6][7][8][9][10][11]21,22], the solution proposed in [23] appears to be the most promising for further investigations. Hence, this paper proposes a simple self-contained solution that is based on the idea introduced in [23] and introduces improvements in the performance regarding fixed-point implementations on digital signal processors (DSPs) and filtering capabilities.…”

“…According to the results of the comparative simulations presented in [23] of the solution proposed in [23] with the solutions from [5][6][7][8][9][10][11]21,22], the solution proposed in [23] appears to be the most promising for further investigations. Hence, this paper proposes a simple self-contained solution that is based on the idea introduced in [23] and introduces improvements in the performance regarding fixed-point implementations on digital signal processors (DSPs) and filtering capabilities.…”