| CPC H02K 15/03 (2013.01) [H02K 1/246 (2013.01); H02K 19/103 (2013.01); H02K 2213/03 (2013.01); Y10T 29/49009 (2015.01)] | 12 Claims |
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1. Method of optimizing a synchronous reluctance motor (1) assisted by magnets, which method includes the following steps:
providing a stator (2) having a certain number (t) of stator slots (3) for stator windings;
providing a rotor (4) having a substantially circular crown shape, an external cylindrical surface (Se) of external radius (re), an internal cylindrical surface (Si) of internal radius (n), a rotation axis (A) and a number (p) of polar pairs;
providing in said rotor (4) a number (n) of rotor slots (7) defining axially developed flow barriers (Bn) for each pole of the motor (1), adapted to house magnets (6);
providing each of said barriers (Bn) with peripheral profile in the shape of a circular segment with convexity facing said rotation axis (A) and with concentric radii of curvature (rnA, rnB) with common centre (C) arranged along a radial axis (X);
wherein said number (n) of barriers (Bn) per pole is greater than or equal to 3 and said common centre (C) is located outside said external cylindrical surface (Se);
wherein each of said flow barriers (Bn) per pole has a constant thickness (bn) along its arcuate development defined by the difference between said radii of curvature (rnA, rnB);
wherein the thicknesses (bn) of said barriers (Bn) are progressively decreasing from the internal surface (Si) to the external surface (Se) of the rotor (4) with optimal thickness (bn) of the external barrier (Bn) equal to bn=kn−1b1,
wherein kn−1 is a numerical coefficient relative to the nth barrier, said coefficient being determined so as to obtain a substantially constant magnetic permeance across the barriers (Bn) and a response to an excitation current in quadrature with minimum harmonic content,
characterised in that said thickness (bn) of each of said barriers (Bn) per pole is obtained by the following steps:
determining a first point (G) obtained from the intersection of said external surface (Se) with a first radius (ra) of the rotor (4) forming a first angle (α) with respect to said radial axis (X);
determining a second point (D) obtained by the intersection of said internal surface (Si) with said radial axis (X) and a third point (E) obtained by the intersection of said internal surface (Si) with a secant (h) forming a second angle (B) with said radial axis (X);
determining a circumference of radius (R) passing through said first (G) and second point (D) with centre of curvature (C) located on said radial axis (X);
determining a total value of iron or solid material (F) of the rotor (4) and determining the corresponding number (m) of segments (fm) corresponding to the thickness of said iron or solid material (F) present between said barriers (Bn) per pole; and
determining said radii of curvature (rnA, rnB) and consequently the thickness (bi) of the innermost barrier (Bi),
wherein said radii of curvature (rnA, rnB) and said thickness (bn) of each barrier (Bn) per pole is determined by the relation b1+b2+ . . . +bn=ra−n−F,
wherein b2=k1b1,
wherein F=½f1+f1+f2+ . . . +fm,
wherein f2=j1f1,
wherein fm=jm−1f1,
wherein r1A=R−f½,
wherein r1B=r1A−b1,
wherein r2A=r1A−f1-b1,
wherein r2B=12A−b2,
wherein rnA=r(n−1)A−fn−1−bn−1,
wherein rnB=rnA−bn,
and wherein j1 . . . jm−1 are numerical constants relating to said segments (f) mths obtained by means of experimental simulations and results, and adapted for obtaining a substantially sinusoidal distribution of the magnetic flux in the rotor iron.
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