Research Of On-Line UPS Based On DSP

Uninterruptible Power Supply (UPS) is a power electronic device which provideshigh quality and uninterruptible electronic power. It is used so widely that it hasbecome standard device in many fields. How to realize digital control of UPS withDSP is now concerned about by many UPS designers. There are two main aspectsin which DSP is applied to UPS, one is to adopt various advanced control methods forinverter real-time numerical control and the other is to achieve more accurate andmore rapid phase-lock loop (PLL).This paper analyses the present control patterns of inverter. Taking into accountthat the disturbance and high frequency waveform of inverter output voltage appearperiodically;this paper adopts repetitive control to improve the steady statequalification of inverter output. Because the effect of repetitive control is delayed forone period, this paper also adopts PID control to improve the transient qualification ofinverter output. After analyzing the common control pattern of repetitive control, onthe basis of establishing the model of inverter and filter, this paper designs a newcontrol pattern which combines PID and repetitive control together. The new controlpattern is simulated in MATLAB and the result proves that the design is effective.The interface circuits of DSP and other UPS circuits are designed which includesthe power supply circuit of DSP, low cell voltage detection circuit, and voltage zerocross detection circuit. This paper allocates the resources of DSP and makes full useof its abound resources and the notable operation speed.This paper designs the whole program which includes the main program,software phase-lock loop and sine wave generation program, the outputroot-mean-square quality control program and the relevant interruption and protectionprograms.The experiment circuits are established according to the present devices. Thetheorem and the circuits of the experiment are demonstrated. The experiment set canbe used for inverter control and phase-lock loop control.This paper combines PID and repetitive control together to control inverter. Thesimulation proves the effectiveness of the control pattern. This paper also studies thedigital control of UPS with DSP. All this has promotion effect in technique advance inUPS.