Control apparatus for thyristor motor

摘要

A control apparatus for thyristor motor comprises a voltage detector (27), a speed detecting circuit (600) and a correction circuit (800). The voltage detector (27) detects DC voltage (Ed) supplied to an inverter circuit (200). The speed detecting circuit (600) detects the rotational speed of a synchronous motor (3) and provides speed voltage (E omega ) proportional thereto. The correction circuit (800) detects a difference between the detected DC voltage (Ed) and the speed voltage (E omega ) and provides a correction signal to an excitation circuit (700) when a difference is detected. The excitation circuit (700) corrects field current in response to the correction signal so that the DC voltage (Ed) and the speed voltage may be equal. Thus, a proportional relation can be maintained between the instructed torque and the generated torque.