Patent ID: 6998757

Claim:
A multi-rotor synchronous machine, comprising: a pair of rotors at least one of which has permanent magnet field poles, said rotors being arrayed coaxially to be rotatable relative to each other; a stator core; armature coils wound in said stator core, interlinking with a field flux produced by said rotors; a sensor measuring a relative angle between said rotors; and a rotor-to-rotor relative angle controller working to establish a relative rotation between said rotors to change the relative angle measured by said sensor to a target angle, wherein: said stator core is made of a hollow cylindrical member, said rotors are an outer rotor disposed around an outer periphery of said stator core and an inner rotor disposed around an inner periphery of said stator core, said rotor-to-rotor relative angel controller includes a relative rotation controlling mechanism disposed inside said inner rotor for controlling a relative rotation between said rotors, said relative rotation controlling mechanism includes an elastic member laid between said rotors in a circumferential direction thereof to keep said rotors in a neutral position, and said rotor-to-rotor relative angle controller changes magnetic torques acting on said rotors to adjust a relative angle between said rotors to a target angle.