A motor rotor, comprising a rotor core and a plurality of magnetic poles provided in the rotor core, wherein permanent magnets of the magnetic pole are designed to be of a W-shaped structure, the magnetic pole comprises a first permanent magnet, a second permanent magnet, and a third permanent magnet,the first permanent magnet being arranged at the central position of the corresponding magnetic pole, the second permanent magnet being arranged at two sides of the corresponding first permanent magnet, the third permanent magnet being arranged at one side, away from the first permanent magnet, of the corresponding second permanent magnet; the coercivity of the first permanent magnet is less than the coercivity of the second permanent magnet and the coercivity of the third permanent magnet; wherein the third permanent magnet is arranged on a q axis of a motor; the size relationship of the first permanent magnet, the second permanent magnet and the third permanent magnet in a cross-section orthogonal to the rotor core axis meets m/2>H1 ∗ Hcj1 ∗ L1/(H2 ∗ Hcj2 ∗ L2+1/2 ∗ H3 ∗ Hcj2 ∗ L3)>m/10, wherein L1 is the length of the first permanent magnet; H1 is the width of the first permanent magnet; Hcj1 is the intrinsic coercivity of the first permanent magnet; L2 is the length of the second permanent magnet; H2 is the width of the second permanent magnet; Hcj2 is the intrinsic coercivity of the second permanent magnet; L3 is the length of the third permanent magnet; H3 is the width of the third permanent magnet; and Hcj3 is the intrinsic coercivity of the third permanent magnet;, wherein m is a factor regarding an adjustment range of flux for the motor, and m is obtained according to the following formula: Br 2 * Hcj 2 * 2 * H 2 * L 2 + H 3 * L 3 + Br 1 * Hcj 1 * H 1 * L 1 / Br 2 * Hcj 2 * 2 * H 2 * L 2 + H3 * L3 * Br 2 * 2 * H 2 * L 2 + N 3 * L 3 / Br 2 * 2 * H 2 * L 2 + H 3 * L 3 − Br 1 * H 1 * L 1 = m, wherein Br1 is the remanence of the first permanent magnet, Br2 is the remanence of the second permanent magnet, and Br3 is the remanence of the third permanent magnet. wherein the third permanent magnet is arranged on a q axis of a motor; the size relationship of the first permanent magnet, the second permanent magnet and the third permanent magnet in a cross-section orthogonal to the rotor core axis meets m/2>H1 ∗ Hcj1 ∗ L1/(H2 ∗ Hcj2 ∗ L2+1/2 ∗ H3 ∗ Hcj2 ∗ L3)>m/10, wherein L1 is the length of the first permanent magnet; H1 is the width of the first permanent magnet; Hcj1 is the intrinsic coercivity of the first permanent magnet; L2 is the length of the second permanent magnet; H2 is the width of the second permanent magnet; Hcj2 is the intrinsic coercivity of the second permanent magnet; L3 is the length of the third permanent magnet; H3 is the width of the third permanent magnet; and Hcj3 is the intrinsic coercivity of the third permanent magnet;, wherein m is a factor regarding an adjustment range of flux for the motor, and m is obtained according to the following formula: Br 2 * Hcj 2 * 2 * H 2 * L 2 + H 3 * L 3 + Br 1 * Hcj 1 * H 1 * L 1 / Br 2 * Hcj 2 * 2 * H 2 * L 2 + H3 * L3 * Br 2 * 2 * H 2 * L 2 + N 3 * L 3 / Br 2 * 2 * H 2 * L 2 + H 3 * L 3 − Br 1 * H 1 * L 1 = m, wherein Br1 is the remanence of the first permanent magnet, Br2 is the remanence of the second permanent magnet, and Br3 is the remanence of the third permanent magnet.