Impact of Modulation Ratio on Output Voltage Harmonic in UPS Inverter Circuit
This paper thoroughly analyzes the characteristics,types,evaluation indicators and control meth-ods of the core part(inverter circuit)of the UPS in detail,then,the widely used single-phase bipolar SP-WM full-bridge inverter circuit is taken as the research object,and the expression of the average output voltage of the inverter circuit is derived.The influence of typical values of frequency modulation and am-plitude modulation on output voltage harmonics is discussed by means of the combination of simulation and theory.It is found that when the carrier frequency is odd times of the modulated wave frequency,the amplitude modulation system r=0.9,and when the carrier frequency is even times of the modulation wave frequency,the amplitude modulation system r=0.5.At this time,the output inverter voltage waveform quality is better,and the harmonic content is smaller.The research has a certain reference value for impro-ving the design of inverter circuit and the selection of parameters.
uninterruptible power supplyfull bridgeinverter circuitmodulation ratioharmonic distor-tion
万方数据
维普
