INVERTER CONTROL METHOD OF NON-INTERRUPTION POWER SUPPLY APPARATUS AND NON-INTERRUPTION POWER SUPPLY APPARATUS

摘要

PURPOSE: To improve the utilization factor of a DC voltage by a method wherein a modulation method with a third harmonic, etc., is applied to a non-interruption power supply apparatus whose phase voltages are controlled by the feedback of the phase voltages detected from line voltages. ;CONSTITUTION: The line voltages of the output voltages of an inverter 2 are detected by a voltage transformer 6 and the respective phase voltages are obtained by a converting circuit 7. Phase voltage control signals corresponding to the deviations between the detected phase voltage values and command sine wave phase voltages are generated by voltage control circuits 8u, 8v and 8w. Further, in order to modulate predetermined carrier waves by modulating circuits 11u, 11v and 11w with the phase voltage control signals as modulation waves to generator PWM pulses for driving the switching devices of the inverter 2, a negative side envelope signal generating circuit 15 which superposes signals corresponding to negative envelopes related to three-phase waveforms of the command sine wave voltages or the phase voltage control signals on the modulation waves is provided. Instead of superposing the negative side envelope signals on the modulation waves, the third harmonics of the command phase voltages may be superposed on the modulation waves.;COPYRIGHT: (C)1993,JPO&Japio