Research And Design Of UPS Rectifier Module Based On High-Efficient SiC Device

With the development of power electronics technology, the indicators of power electronic devices has been greatly improved. However, subject to the restriction of semiconductor material, device made of Si is inferior to the device made of new semiconductor material. As a representative of new semiconductor devices, important parameters of Si C power components are very advantageous. MOSFET made of Si C has higher voltage tolerance, lower on-resistance, stronger thermal stability, higher switching frequency and lower switching loss. In short, Si C MOSFET has a very good application foreground. Commissioned by an enterprise, the main task of this paper is to develop an IGBT uninterruptible power supply rectifier, and on this basis, to study Si C MOSFET uninterruptible power supply rectifier preliminarily.Firstly, this paper built the switching model of the rectifier in the three-phase stationary coordinate system, in the two-phase stationary Cartesian coordinate system and the two-phase rotating Cartesian coordinate system respectively. For each module of the rectifier control system, the paper also expounded in detail.Secondly, directed to startup overshoot using both the voltage PI control strategy and the current PI control strategy, this paper proposes a modified PI control strategy. Improved PI control strategy can be applied to the DC voltage control to effectively reduce the startup overshoot. Then the DC voltage and the AC current will changes gently during the startup process. Thus, device requirements can be lowered.Meanwhile, for rectifier using the space vector pulse width modulation, this paper determines upper and lower limits of the AC side inductance value through the analysis of the AC current harmonics, and then determine the inductance value by simulation tools. Through the method proposed by this paper, inductance meeting the harmonics requirements can be selected. In order to verify the correctness of the method, experiment have been carried out.Furthermore, the paper developed two rectifiers with Si IGBT and Si C MOSFET, and designed the corresponding peripheral circuits respectively. During the experiment, the correctness and effectiveness of the modified PI control strategy and the inductance selection method were verified, and the Si C MOSFET uninterruptible power supply rectifier was studied preliminarily.In short, this paper uses a combination of theory and practice and a combination of simulation and experiments to verify the correctness and effectiveness of the inductance selection method and the improved PI controller. And the preliminary study of Si C MOSFET uninterruptible power supply rectifier was carried out.