METHOD FOR DETECTING OPEN-PHASE OF POWER SUPPLY OF THREE-PHASE CONVERTER

摘要

An open-phase detecting method wherein a simple hardware structure is used to achieve a reduced cost; the IRQ number is reduced to reduce the load on a CPU; the open phase detection is performed in two terms, that is, a phase difference and a voltage sign to reduce the possibility of occurrence of erroneous detections; and any phase that is open can be also determined. In the method for detecting any open phase of the power supply of a three-phase converter, a neutral point (N1) is connected to the negative pole side bus (N) of the DC side output of rectifying means; an end of a first resistor of each phase, which corrects the first resistor to a second resistor of a respective phase, is connected to an AD converter via a high input impedance means of the respective phase to detect the voltage of the respective phase; the voltage of the respective phase is outputted to a CPU that serves as open-phase detecting means; and an open phase is detected when the signs of two of the three-phase interline voltages determined based on the voltages of the respective phases are different from each other and the phase difference exhibits a half-wave rectification waveform of 180 degrees.