发表于:2003-07-30 11:56:00
2楼
ups is a CVCF inverter ,but has many commmon points with inverters in AC drive.For a ups inverter,the output voltage waveform is highly demanded,such as,when under linear loads,the THD must below 2%,and under nonlinear loads,e.g. a diode rectifier with large capacitor filtering,the THD should be limited below 8%. meantime,this kind of inverter must has good steady and dynamic performance,for instance,when add or reduce loads,the dynamic reponse time should be less than 20ms.
ups control schemes are mostly regulated with spwm method.at the same time,feedback must be designed(voltage feedback and current feedback).the reference signal then is compared with the feedback signal to get the error signal,which was modulated by triangle signal to get spwm pulse,after drive,then the power switchs can work now.a low pass filter composed of inductor and capacitor eliminate the high frequency harmonics,the pure sinusoidal can be achieved!
hope the above hints can bring u helps