| 摘要 |
PROBLEM TO BE SOLVED: To compensate for the fluctuating output voltage, without depending on negative feedback, resulting from the fluctuating main power source voltage of a PWM power converter because it is difficult to stably apply a large amount of feedback to the output voltage. SOLUTION: An oscillator 3 is controlled to generate a square wave of a carrier frequency to operate a half-bridge inverter 4. The square wave of the inverter 4 is applied to an integration circuit 7 via a transformer 5. This transformer 5 is provided to insulate between the main power source 1 and a control circuit and to supply the square wave 6 of an adequate amplitude to the integration circuit 7. A PWM signal 11 can be obtained through comparison of an input signal 9 and a PWM carrier 8 in a comparator 10. This PWM signal 11 is used to originate a control signal of a power converting circuit 12. This power converting circuit 12 switches the main power source 1 to obtain an output 13 of the PWM power converter. As a result, fluctuation of the main power source voltage can be canceled by adding a small capacity inverter to the PWM power converter. More stable operation and sufficient effect can be attained than with a method utilizing negative feedback of an output voltage. |
