Method for Identifying the Spatial Harmonic Flux-Map of a Synchronous Electrical Machine, and Method for Torque Ripple Map Evaluation Without Torque Measurement

A method for identifying the spatial harmonic flux-map of an electrical machine, the method comprising:

• driving said electrical machine at a constant speed by an external driver;
• scanning a dq current plane of said electrical machine by a proportional-integral current controller;
• acquiring phase current, line voltage and rotor position of said electrical machine during said scanning;
• calculating a stator flux-linkage, in a stationary reference frame αβ, from a voltage equation from at least one electrical cycle data as
• λ
• αβ
• =
• ∫
• (
• v
• αβ
• -
• R
• s
• ⁢
• i
• αβ
• )
• ⁢
• dt
• wherein
• λαβ is the stator flux-linkage vector in a stationary reference frame;
• vαβ is the stator voltage vector in a stationary reference frame;
• Rs is the stator resistance and
• iαβ is the stator current vector in a stationary reference frame;
• extracting harmonics in the measured phase current by a Fourier transform;
• extracting harmonics in the estimated stator flux in a synchronous reference frame by a Fourier transform;
• wherein the expressions Λd=IdLd+Λm;
• Λq=IqLq hold
• wherein
• Λd;
• Λq;
• λm are columns vector flux matrix,
• Id;
• Iq are a square matrix,
• Ld;
• Lq are inductance columns vector matrix.