Design Of A New Style Electronic Load System Based On 80C196KC Single-chip Microcomputer

Uninterruptible power supplies(UPS) are more and more extensively applied in each section of industry. Production and research of UPS has became a hotspot in power electronic industry. Testing of UPS is very necessary before they are used. Traditional UPS reliability testing usually takes the measures of discharging by the big resistance, this measure not only wastes a great deal of electronical power, but also because volume of resistance load is very huge and needs special cooling device, it takes up production room. The dissertation brings forward a kind of automatic electronic load, it can not only replace of resistance load to discharge, but also transfer output energy back to AC power network in testing of UPS and the other high-power supplies. This measure saves energy, reduces production cost and has the merits of small volume and light weight. The dissertation presents the design of a new style single-phase electronic load system based on 80C196KC single-chip microcomputer by which boost and invert process are controlled according to actual requirement. The design can make output electronical energy be transferred back to AC power network at unit power factor. It saves greatly energy and reduces harmonic pollution.The dissertation analyzes the principle of BOOST transform circuit and designs DC/DC boost converter circuit according to this principle. The circuit controls input current and bus voltage by means of double loop PWM control. The dissertation builds up computer simulating model of voltage loop control.The dissertation designs single-phase full-bridge inverter by analyzing the principle of voltage inverter and method of current control. The system can make output current of inverter follow power network voltage by using software lock-phase to inspected signal of power network voltage. The dissertation analyzes harmonic current and the dead time effect of inverter. The dissertation analyzes the control system hardware design in detail and introduces design method of system software. It presents the selection method of digital control PI adjusting parameter on the basis of simulating model. And it also presents a part of hardware schematics and software flowcharts.At the end of this dissertation, the experiment results of the system are provided, and these results show that the system can obtain well output current following performance and unit power factor. And in the experiment process, the voltage and current do not shift, and the process of lock-phase is very quick and smooth. The system basically realizes the function that the energy discharged by UPS is transferred back to AC power network.