| 摘要 |
PURPOSE:To obtain a simple and inexpensive PWM inverter by dividing the frequency of the output of the first voltage-to-frequency converter, applying it to a memory, and counting the number of the output pulses of the second voltage-to- frequency converter until coinciding with the data of the memory. CONSTITUTION:A pulse proportional to the control voltage V outputted from the first voltage-to-frequency converter 1 is divided in frequency, and applied to an ROM block 3 which stores data of the different pulse width in each phase of AC output to be converted. The pulses of high frequency from the first converter 1 outputted from the second voltage-to-frequency converter 6 is counted until coinciding with the data of the block 3 by six counters 4, transistors Tr1-Tr6 of a drive circuit 8 are controlled through a flip-flop 5, thereby driving a motor 7. Accordingly, the rotating speed can be controlled without a frequency inverter, and the configuration is simplified and reduced in cost. |
