| 摘要 |
PURPOSE:To reduce the size and to shorten the processing time by detecting the current flowing through an inverter circuit and determining a current command value based on the difference between the detected current value and a target current value thereby employing only one current detector. CONSTITUTION:A current control means 10 amplifies the difference between a target current value Ic fed from a host system or a speed amplifier and a current value If fed back from a current detector and a current command value is fed to a multiplying means 9. The multiplying means 9 multiplies the output from the current control means 10 by three signals, obtained by converting the output from a position detector 2 according to a ROM table in a sine wave generating means 8, and provides the products to PWM circuits 5, 6, 7, respectively. Switching transistor in an inverter circuit 3 is then turned ON/OFF by the PWM signal and current flows through each phase coil of a synchronous motor 1 thus rotating the synchronous motor 1. Since only one current detector is required, the size of controller is reduced and since multiplication is required only one time, processing time of microcomputor is shortened in current control. |
