Dsp Controlled Soft-switching Single-phase Line Ups Research

According to the new development of Power Electronics, an experimental control system based on TMS320LF2407 for single-phase on-line UPS is proposed in the dissertation. The whole solution of hardware and software is presented based on the resource of the DSP controller chip. The hardware of the control system mainly consists of the sampling and pre-processing units of analog signals such as output voltage, output current, input voltage, etc, and the insulation and driving units of PWM signals. UC3842 is creatively used to compose the driving circuit. So it can not only achieve the basic insulation and the driving function, but also can achieve the self-dection of the driving circuit, the overcurrent protection and the zero voltage dection of IGBT. The software includes procedures to control and monitor the UPS such as software PLL(Phase-locked Loops), the value modulation of the output voltage and the producing of PWM signals. In this paper, the technique of soft switching is used in the inverter. So the efficiency of inverter is improved, the electromagnetic disturbance is reduced, and the device works in more secure range. The whole digital design make the control and debugging more convenient, the modification of control strategy, control parameter more easier and the embedding of malfunction inspection, self-diagnosis, correction and communication more easier. The number of component is decreased, so the system malfunction which is caused by the component is decreased in the same time and the reliability is enhanced.Finally based on the above theory analysis and simulation results in this paper makes some conelative experiment. Experiment result indicates that the voltage of inverter switch has become zero voltage situations before the switch trigger signal coming. So it realizes that the zero voltage soft-switching is achieved. The voltage peak value is decreased obviously at the on time, so the switch loss is decreased too. At the same time, the THD is reduced obviously, so the quality of output wave is improved. When the load is unloaded suddenly, the fluctuation of close-loop output waveform is smaller than the open-loop and the homeostatic peak value of voltage is stable. The whole system has nice input and output character. It can offer perfect power supply for many situations.