1,142 research outputs found
Cross-Saturation Effects in IPM Motors and Related Impact on Sensorless Control
Permanent-magnet-assisted synchronous reluctance motors are well suited to zero-speed sensorless control because of their inherently salient behavior. However, the cross-saturation effect can lead to large errors on the position estimate, which is based on the differential anisotropy. These errors are quantified in this paper as a function of the working point. The errors that are calculated are then found to be in good accordance with the purposely obtained experimental measurement
Improved rotor-position estimation by signal injection in brushless AC motors, accounting for cross-coupling magnetic saturation
This paper presents an improved signal-injection- based sensorless-control method for permanent-magnet brushless ac (BLAC) motors, accounting for the influence of cross-coupling magnetic saturation between the d- and q-axes. The d- and q-axis incremental self-inductances, the incremental mutual inductance between the d-axis and q-axis, and the cross-coupling factor are determined by finite-element analysis. An experimental method is proposed for measuring the cross-coupling factor which can be used directly in the sensorless-control scheme. Both measurements and predictions show that a significant improvement in the accu- racy of the rotor-position estimation can be achieved under both dynamic and steady-state operation compared with that which is obtained with the conventional signal-injection method
Improved rotor position estimation by signal injection in brushless AC motors, accounting for cross-coupling magnetic saturation
The paper presents an improved signal injection- based sensorless control method for permanent magnet brushless AC (BLAC) motors, accounting for the influence of cross-coupling magnetic saturation between the d- and q-axes. The d- and q-axis incremental self-inductances, the incremental mutual-inductance between the (d-axis and q-axis, and the cross-coupling factor are determined by finite element analysis. A method is also proposed for measuring the cross-coupling factor which can be used directly in the sensorless control scheme. Both measurements and predictions show that a significant improvement in the accuracy of the rotor position estimation can be achieved under both dynamic and steady-state operation, compared with that which is obtained with the conventional signal injection method
On the stator flux linkage estimation of an PMSM with extended Kalman filters
The demand for drives with high quality torque control has grown tremendously in a wide variety of applications. Direct torque control (DTC) for permanent magnet synchronous motors can provide this accurate and fast torque control. When applying DTC the change of the stator flux linkage vector is controlled. As such the estimation of the stator flux linkage is essential. In this paper the performance of the Extended Kalman Filter (EKF) for stator flux linkage estimation is studied. Starting from a formulation of the EKF for isotropic motors, the influence of rotor anisotropy and saturation is evaluated. Subsequently it is expanded to highly isotropic motors as well. In both cases the possibilities to add parameter estimations are evaluated
Estimation of Saturation of Permanent-Magnet Synchronous Motors Through an Energy-Based Model
We propose a parametric model of the saturated Permanent-Magnet Synchronous
Motor (PMSM) together with an estimation method of the magnetic parameters. The
model is based on an energy function which simply encompasses the saturation
effects. Injection of fast-varying pulsating voltages and measurements of the
resulting current ripples then permit to identify the magnetic parameters by
linear least squares. Experimental results on a surface-mounted PMSM and an
interoir magnet PMSM illustrate the relevance of the approach.Comment: IEMDC-2011 (preliminary version
Signal injection and averaging for position estimation of Permanent-Magnet Synchronous Motors
Sensorless control of Permanent-Magnet Synchronous Motors at low velocity
remains a challenging task. A now well-established method consists in injecting
a high-frequency signal and use the rotor saliency, both geometric and
magnetic-saturation induced. This paper proposes a clear and original analysis
based on second-order averaging of how to recover the position information from
signal injection; this analysis blends well with a general model of magnetic
saturation. It also experimentally demonstrates the relevance for position
estimation of a simple parametric saturation model recently introduced by the
authors
High-frequency issues using rotating voltage injections intended for position self-sensing
The rotor position is required in many control schemes in electrical drives. Replacing position sensors by machine self-sensing estimators increases reliability and reduces cost. Solutions based on tracking magnetic anisotropies through the monitoring of the incremental inductance variations are efficient at low-speed and standstill operations. This inductance can be estimated by measuring the response to the injection of high-frequency signals. In general however, the selection of the optimal frequency is not addressed thoroughly. In this paper, we propose discrete-time operations based on a rotating voltage injection at frequencies up to one third of the sampling frequency used by the digital controller. The impact on the rotation-drive, the computational requirement, the robustness and the effect of the resistance on the position estimation are analyzed regarding the signal frequency
Improved signal injection based sensorless technique for PM brushless AC drives
The accuracy of rotor position estimation in the conventional signal injection based sensorless control of permanent magnet brushless AC drives depends on the load current. This paper proposes an improved method, which significantly reduces the estimation error by accounting for the cross-coupling effect between the d-and q-axes. The conventional and proposed methods are described and their performance is compared by both simulation and experiment
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