Research On The Control Technology Of The Paralleled DC/DC Converter Modules

With the increasing demand of large power load and the development of distributed power supply system, the importance of research on paralleled power supply modules is increasing, while how to achieve the equilibration of output currents is the key technology of making the modules work in parallel. At present most current-sharing control are achieved in condition that the approximate linearization small-signal models, so it is difficult to find the scheme which can optimize the stability and dynamics at the same time. Aiming at this problem, integral sliding-mode control and one-cycle control are applied to the paralleled DC/DC converters in this thesis in order to enhance the steady and dynamic current-sharing control performances of paralleled power supply systems. From the references which have been mentioned, the researches on this aspect are seldom discussed.On the one hand, integral sliding-mode control is applied to paralleled power supply modules in this thesis. Based on the simulation model established by MATLAB/SIMULINK platform, the detailed comparisons are taken between the proposed approach and the reference's method. The simulation results show that the proposed integral sliding-mode current-sharing control scheme can achieve good steady-state voltage and steady and dynamic performances whatever large parameter differences or large signal disturbances. These results also well prove that the validation and superiority of the proposed method in this thesis.On the other hand, by analyzing the one-cycle control theory, a current-sharing control scheme using one cycle control is proposed in this thesis, and the simulation of it is done with PSPICE software. The results show that this nonlinear current-sharing control scheme is characterized by good steady and dynamic performances. On the basis of researches above, a prototype which consists of two paralleled DC/DC SEPIC converters with coupled inductors is designed. Some experiments have been made. The experimental results show that the approach proposed is accurate and feasible again.