초록 ▼

In a motor with permanent magnets and a motor system, the value .alpha. produced by dividing, by the induced voltage constant ke, the product of the inductance Lm of the motor itself or the inductance Ls of the motor system in the d-q coordinate system is selected to meet a predetermined condition.

In a motor with permanent magnets and a motor system, the value .alpha. produced by dividing, by the induced voltage constant ke, the product of the inductance Lm of the motor itself or the inductance Ls of the motor system in the d-q coordinate system is selected to meet a predetermined condition. The range of rotational speeds in which the motor can be operated while maintaining a predetermined output under field weakening control can be widened. If a condition is established to determine a ratio by which the rated rotational speed under normal operating conditions is multiplied into a rotational speed under field weakening control, then conditions for a motor or a motor system that can be used can be determined.

대표청구항 ▼

[ I claim:] [1.] A synchronous motor optimized for running under equivalent field weakening control, havinga rotor comprising permanent magnets;an inductance La which is determined by an equation (a), where Ip is a rated current, Ke is an induced voltage constant in a d/q-axis conversion system of t

[ I claim:] [1.] A synchronous motor optimized for running under equivalent field weakening control, havinga rotor comprising permanent magnets;an inductance La which is determined by an equation (a), where Ip is a rated current, Ke is an induced voltage constant in a d/q-axis conversion system of the synchronous motor, and .alpha. is in a range represented by an inequality (b): ]EQU16 ] where k is a ratio by which a rated rotational speed can be multiplied to a rotational speed for operation without reducing motor output below rated output.