| 摘要 |
PROBLEM TO BE SOLVED: To obtain a control method in which a constant output can be controlled over a wide range by a method wherein the phase angle of a two-phase current command signal generated by a current-command DC/AC conversion circuit is prescribed by a specific linear function with reference to the rotation speed of a permanent-magnet synchronous motor. SOLUTION: A current-distribution-signal generation part 12 is formed at a command-current DC/AC conversion circuit 8, and the phase angle θ of every phase-current signal generated from the part is prescribed by an expression as a linear function of θ(N)=θi +γ.N with reference to the rotation speed N of a motor, and the motor is controlled. In the equation, θi represents a phase angle command when N=0, γ represents a positive grade when γ=(θmax -θi )/ Nmax , θmax represents a phase angle command at a maximum rotation speed, and Nmax represents a maximum rotation speed. Thereby, in a constant torque region, the motor can be controlled at an optimum phase angle at which a reluctance torque can be used most efficiently, and, in a constant output region in which a voltage is saturated, the motor is controlled by a weak field system. As a result, a constant output can be controlled over a wide range. |
