| 摘要 |
PROBLEM TO BE SOLVED: To enhance power of AC voltage output by an inverter device while performing control so that crest voltage of the AC voltage is constant.SOLUTION: A control circuit 5 performs on/off control of a switching element 4 for switching input voltage to make excitation current flow in excitation winding Np of a transformer 3 during a period in which the switching element is on and output AC voltage from output winding Ns during a period in which the switching element is off. A zero-cross detection circuit 6 detects a zero-cross point of AC voltage Vf which is generated by subordination winding Nf provided on the secondary side of the transformer 3 so as to have a waveform similar to the AC voltage output from the output winding Ns and voltage extremely lower than the AC voltage. A counter circuit 7 counts zero-cross detection signals Sz from the zero-cross detection circuit 6. When a value of the count reaches a setting value of a setting unit 9, an output signal Sc of a comparison circuit 8 reverses to make the control circuit 5 perform control of switching the state of the switching element 4 from off to on. |
