3,307 research outputs found
An analysis of the benefits of signal injection for low-speed sensorless control of induction motors
We analyze why low-speed sensorless control of the IM is intrinsically
difficult, and what is gained by signal injection. The explanation relies on
the control-theoretic concept of observability applied to a general model of
the saturated IM. We show that the IM is not observable when the stator speed
is zero in the absence of signal injection, but that observability is restored
thanks to signal injection and magnetic saturation. The analysis also reveals
that existing sensorless algorithms based on signal injection may perform
poorly for some IMs under particular operating conditions. The approach is
illustrated by simulations and experimental data
Multi-physic system simplification method applied to a helicopter flight axis active control
A helicopter flight axis control, which is a complex multi-physic system, is modelled using an energetic based graphical tool: the Energetic Macroscopic Representation. Elements of the system are mainly composed of passive technologies and their number tends to increase year after year to improve the pilots comfort by adding new functions. A new methodology is proposed to transform the system into a new active one by replacing some hydro-mechanical elements by a new controllable active mechanical source. The challenge is to simplify the flight control architecture while preserving the global behaviour of the system
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
Adding virtual measurements by signal injection
We propose a method to "create" a new measurement output by exciting the
system with a high-frequency oscillation. This new "virtual" measurement may be
useful to facilitate the design of a suitable control law. The approach is
especially interesting when the observability from the actual output
degenerates at a steady-state regime of interest. The proposed method is based
on second-order averaging and is illustrated by simulations on a simple
third-order system
Energy-based modeling of electric motors
We propose a new approach to model electrical machines based on energy
considerations and construction symmetries of the motor. We detail the approach
on the Permanent-Magnet Synchronous Motor and show that it can be extended to
Synchronous Reluctance Motor and Induction Motor. Thanks to this approach we
recover the usual models without any tedious computation. We also consider
effects due to non-sinusoidal windings or saturation and provide experimental
data
Challenges in experimental data integration within genome-scale metabolic models
A report of the meeting "Challenges in experimental data integration within
genome-scale metabolic models", Institut Henri Poincar\'e, Paris, October 10-11
2009, organized by the CNRS-MPG joint program in Systems Biology.Comment: 5 page
Nouvelle contribution Ă la connaissance de la floraison et de la fructification de l'Arachide
Efficient Intra-household Allocations and Distribution Factors:Implications and Identification
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