Three-Level Research On Direct Current Control Strateegy Of Super Capacitor Energy Storage Converter

With the rapid economic development, energy conservation and environmental protection were gotten more and more attention. Therefore, the super capacitor came into being. For large capacity, high power density, fast charge and discharge, high efficiency, long cycle life, no pollution and so on, The super capacitor was widely used in the city rail, electric vehicles, lifting systems and power systems. The direct current control of the three-level super capacitor control strategy were studied in this paper, its content is as follow:Firstly, the working principle of the three-level converter was described. The input and output voltage relationship and the continuous and discontinuous boundary inductance were deduced in different operating modes. The relationship between inductor current ripple and duty cycle was drawn, and was compared with the two-level bidirectional converters.Secondly, the influence of three-level bidirectional DC-DC converter switching vector on neutral point potential in DC side was analyzed, and the three-level bidirectional DC-DC converter was simulated, in which pulse alternative controlling technology was adopted. The effect of three-level converter switch vector on the inductor current in Boost mode and Buck mode were analyzed in this paper. The direct current control was used to complete the charge and discharge control of the three-level super capacitor energy storage converter, According to the redundant vector, the neutral point potential in DC side can be adjusted in real time.Based on PSIM simulating software, simulation model of three-level bidirectional DC-DC super capacitor energy storage converter was constructed, in which the correctness and validity of the design method were proved. This method is simple and effective. The neutral point potential balance effect is good.Finally, the experiment platform of three-level bidirectional DC-DC super capacitor energy storage converter was built in which TMS320F28335 DSP was selected as core controller. The relevant algorithm were completed.