Design Of 3kVA Single-Phase Emergency Power Supply

This thesis gives research on a novel single-phase emergency power supply (EPS) in order to overcome the limitations of the traditional emergency power supply. This EPS system adopts a bidirectional PWM converter, which can charge the VRLA batteries reasonably when the main is normal, if the main power supply interrupts, the system will work in an inverter state automaticaly and supply the load with an emergency power. By using the DSP digital control technique, this EPS system realized the requirements of intelligent and low cost.This paper put emphasis on the control strategy of this novel single-phase emergency power supply, the charging /discharging management of the VRLA battery, and the design process of this system. The feasibility and reliability of this system have been verified by simulation and experimental results.Chapter one introduces the development of EPS systems, and also it compares emergency power supply with uninterruptible power supply (UPS). Then some different control strategies for inverters are also introduced.Chapter two firstly introduces a small signal model of the full bridge topology. Secondly, the characters of the instantaneous current model control strategy with output filter current feedback are introduced in this chapter. And then, the parameters of the control loop are designed.Chapter three describes the charging/discharging characters of VRLA battery and main charging method nowadays.Chapter four introduces operation principles and the design flowchart of the new single-phase converter. The major parameters and design procedures for the EPS system are presented.Chapter five shows the Saber simulation results. And the experimental results from lab made prototype is presented and compared.Chapter six gives the conclusion and future research work.