| 摘要 |
PURPOSE:To compensate inner constants for temperature fluctuation without requiring a high accuracy sensor by compensating the set value of secondary resister with the difference between a detected value of average speed and an estimated speed of a motor as a temperature fluctuation of the secondary resistance. CONSTITUTION:A speed detecting circuit 12 takes out an average angular frequency omegara of a motor 2 and a correction amplifier 15 takes out the difference between the average angular frequency omegara and an estimated rotor angular frequency omegar of the motor under steady state. The detected speed omegara is an actual speed of the motor 2 and the difference, if any, between the detected speed omegara and the estimated speed omegar means some cause of error. If a primary resistor R1 has a true value, error of secondary time constant tau2, i.e., temperature fluctuation of secondary resistor R2 (fluctuation of secondary inductance is quite low), may be accounted for. Consequently, steady speeds omegara and omegar are fed to the correction amplifier 15 which corrects the slip angular frequency omegas so that the difference between the speeds omegara and omegar will be zero thus performing temperature compensation of the secondary resistor R2. |
