| 摘要 |
PROBLEM TO BE SOLVED: To prevent the increase in losses due to the advance phase mode, and lower the current pulsation by changing switching frequency and modulating pulse width, in response to an instantaneous value of voltage of an alternating current power source. SOLUTION: Value of the instantaneous voltage of an alternating current power source which is detected by a full wave rectifier 4, and the reference voltage of a reference voltage generating circuit 5 are compared with each other, so as to decide the switching frequency of an inverter circuit 3. An adder 6 subtracts the output voltage of the reference voltage generating circuit 5 from the output voltage of the full-wave rectifier 4, so as to output the deviation thereof. A carrying wave generating circuit 7 oscillates the switching frequency of MOSFETs, Q1, Q2 of the inverter circuit 3 on the basis of the output signal of the adder 6. A modulation wave generating circuit 8 generates the signal for deciding the pulse width in relation MOSFETs to Q1, Q2. |
