Variable reluctance resolver
Variable reluctance (VR) resolvers applicable to even or odd speed are provided. In an N-phase VR resolver, 2N coil-poles are evenly distributed around the stator, N being odd integer greater than or equal to three. Primary coils are wound with the same number of turns, but their winding polarities alternate across the coil-poles. The number of turns and winding polarities for sine and cosine signal sensing coils are determined by sine and cosine synthesis coefficients of N-phase zero-force transform. The coil turns ratios between sine and cosine signal sensing coils relative to the primary coil are dictated by absolute values of the coefficients, while the winding polarities are determined by signs of the coefficients. In odd-speed VR resolvers, winding polarities of pair of sensing coils symmetrically located 180 degrees apart must be identical, whereas in even-speed VR resolvers, these winding polarities must be opposite.
1. An N-phase variable reluctance resolver apparatus, N being an odd integer greater than or equal to three, the N-phase variable reluctance resolver apparatus comprising:
a stator comprising:
N number of coil-poles that are positioned at equal intervals around the inside of the stator and are referred to as odd coil-poles;
additional N number of coil-poles that are positioned paired with the N odd coil-poles, wherein each of the additional N coil-poles is located symmetrically at 180 degrees relative to its corresponding each of the N odd coil-poles, wherein the additional N number of coil-poles are referred to as even coil-poles; and
three types of coils including a primary coil, a sine signal sensing coil, and a cosine signal sensing coil, which are wound at each of the N odd and N even coil-poles, wherein all primary coils are wired with the same number of coil turns, but with alternating winding polarities between the odd and even coil-poles, wherein the number of turns and winding polarities for the sine signal and cosine signal sensing coils are determined by sine synthesis and cosine synthesis coefficients of a N-phase zero-force (ZF) transform, respectively,
wherein coil turns ratios of the sine signal sensing and cosine signal sensing coils relative to the primary coil on a pair of odd and even coil-poles at position n (1≤n≤N) are determined by absolute values of the corresponding sine synthesis and cosine synthesis coefficients at position n (1≤n≤N) of the N-phase ZF transform, respectively,
wherein coil-winding polarities of the sine signal and the cosine signal sensing coils on a pair of odd and even coil-poles at position n (1≤n≤N) are determined by signs of the corresponding sine synthesis and cosine synthesis coefficients at position n (1≤n≤N) of the N-phase ZF transform, respectively,
a rotor comprising:
a lobe defining at least one electrical period on the stator over one mechanical turn of the rotor.
2. The N-phase variable reluctance resolver apparatus of claim 1 , wherein an odd-numbered speed N-phase variable reluctance resolver is configured, the odd-numbered speed N-phase variable reluctance resolver comprising:
a stator comprising:
the sine signal sensing and cosine signal sensing coils that are wound with identical polarities between the odd and even coil-poles of each paired coil-pole; and
a rotor comprising:
a lobe defining an odd-numbered electrical period on the stator over one mechanical turn of the rotor.
3. The N-phase variable reluctance resolver apparatus of claim 1 , wherein an even-numbered speed N-phase variable reluctance resolver is configured, the even-numbered speed N-phase variable reluctance resolver comprising:
a stator comprising:
the sine signal sensing and cosine signal sensing coils that are wound with opposite polarities between the odd and even coil-poles of each paired coil-pole; and
a rotor comprising:
a lobe defining an even-numbered electrical period on the stator over one mechanical turn of the rotor.