A Bidirectional Dc Convetrer Of Automatic Eauaitzing Oltage Based On The Parallel Structure Of Soft Switch Echnology

Bi-directional DC/DC converter is an important part of the super capacitor that isauxiliary power electric automobile. It plays the role of bidirectional transfer of controlenergy, and direct impact on the dynamic performance and energy recovery of electricautomobile. Super capacitors as the direct application object of the bidirectional DC/DCconverter. Because the monomer super capacitor voltage is not high and the voltage istypically2.7V. In order to meet the needs of the capacity and the voltage value,high-power auxiliary energy systems typically constituted by a plurality of supercapacitors connected in combinations by series and parallel in practical applications. In thecharge-discharge process, due to the discrete nature of parameters between the respectivemonomers，it will lead to the cell voltage of each of the seires is increased or decreased atdifferent speeds, so that each monomer voltage unbalance, and then repeated somemonomer overcharge and over discharge, it will seriously affect the super capacitor energystorage eiffciency of its operational reliability of the group, so their need for supercapacitor in series group voltage balance. Therefore, to achieve all super capacitor voltagebalancing, you can consider the voltage balancing measures from the DC/DC converter.It’s signiifcant for researching an eiffcient bi-directional DC/DC converter with anequalizing function.Designed a parallel structure of the soft-switch technology automatically equalizingbi-directional DC-DC converter, which composed by the DC/DC circuit, DC/AC circuitand a rectiifer circuit three parts, which the DC/DC circuit adopt triple staggered parallelstructure to reduce input and output ripple current, and improve the speed of response.While no auxiliary circuit can make the switch through the phase shitf PWM control in thesoft-switching, the overall loss of the power tube, which they raised is suitable to arbitraryvariable ratio transformer super capacitor voltage equalization measures. Compared withthe existing voltage equalization measures, the method does not require a large detectioncircuit, and is compatible with arbitrary variable ratio transformer on the low accuracy,and the designed variable ratio transformer can be applied to any number of seires supercapacitor group with high lfexibility and versatility. And it can achieve high efifciency andsmall size with relatively small components.First, we propose an eiffcient bi-directional DC/DC converter with an equalizingtfinction topology, and theoretically analyses its Boost mode and Buck mode respectively.Then we design its hardware (each component parameters, IGBT driver its protection, etc.) and software (in DSP2812，including ADC sampling, PWM generation, PID controller,etc.)； Finally, we test the effect of the reducing irpple current,soft-switching group and thesuper capacitor in series equalizing rfom Simulink simulation and experimental debug.