The Flux-Based Sensorless Field-Oriented Control of Permanent Magnet Synchronous Motors without Integrational Drift

Abstract

Abstract:The magnitude of the rotor magnetic flux linkage and its spatial orientation within a permanent magnet synchronous motor directly define the angular position of the rotor and are thus used in many sensorless applications as the governing variables. The rotor magnetic flux linkage in the stator reference frame is represented by two orthogonal sinusoids whose amplitudes and phases are determined by the integration of the orthogonal components of the corresponding voltage, which, due to DC offsets and initial conditions at transient states, result in an integrational drift. This paper proposes a solution to the problem of such integrational drift in the form of a compensation based only on orthogonal properties of waveforms in the stator reference frame. That makes it completely independent of electrical parameters of the motor. As a result, the proposed compensation of the integrational drift does not require any optimization by the user and it is functional from a standstill. The effectiveness of the proposed compensation is demonstrated analytically, by a simulation, and an experiment on a real motor by a simple observer for the sensorless field-oriented control based on the voltage model in the stator reference frame.

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

“…Since these methods contain the sums of squared values under square roots in the Cartesian to polar conversions, they require 32-bit implementation that makes them unsuitable for inexpensive applications. Solutions with integrators are proposed in [20][21][22][23], where the solution proposed in [20] exhibits limited dynamics that can be seen from the settling time in the presented measurements. 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.…”

“…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.…”

“…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. The proposed solution, therefore, offers the dynamics of the solution proposed in [23] with the filtering properties of LPFs. The idea of the proposed solution is presented analytically, its stability is proven by means of the quadratic Lyapunov theory, and its functionality is demonstrated by standalone simulations and experiments within the sensorless FOC of a permanent magnet synchronous machine (PMSM).…”

“…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.…”