| 摘要 |
PROBLEM TO BE SOLVED: To enable application to all-purpose usages at low cost. SOLUTION: A rectifier comprises a three-phase controlling rectifying device 50 where the middle points on the sides corresponding to three respective phases with switching elements SW-A, SW-B and diodes DA, DB anti-parallel-connected with the upper side and lower side, respectively, are connected with the respective phases of a three-phase alternating-current power supply through reactors; a smoothing capacitor 70 parallel-connected with the output end of the three- phase controlling rectifying device 50 through an inrush current preventing device 60 in series; a switching element driving device 30 that outputs control signals for controlling the conduction of switching elements according to triangular-wave voltage and sine-wave voltage generated from a PWM signal generator 40; and a phase detector 10 that provides the switching element driving device with phase signals based on the phase voltages of the AC power supply. The sides of the phase detector 10, connecting the respective phases of the power supply and neutral points, are formed from a series circuit comprising a resistor and a photocoupler and a parallel circuit comprising a capacitor, respectively, and produces output to the switching element driving device based on the output of the photocouplers. |
