MOTOR DRIVE SYSTEM

摘要

In a system for driving an AC motor in which motor current is feedback-controlled, normally, a motor current instruction is generated according to a torque instruction value on the optimal efficiency characteristic line (CL0) so as to select an optimal current phase to obtain a maximum output torque against the same motor current amplitude. On the other hand, when an excessive generation power exceeding the regenerative power from the AC motor is generated on the AC motor, consumption operation is performed to intentionally increasing the power loss in the AC motor. During the consumption operation, s motor current instruction is generated in accordance with the torque instruction value on the loss increase characteristic line (CL1 to CL3) so as to change the current phase from the optimal value Thus, it is possible to consume surplus power by increasing the power loss in the AC motor without causing instability of the motor control.