Design and implementation of a proper modulation and control scheme for a single and three phases Dual Active Bridge Converter

Report, 2014

In this master thesis, the aim is to implement the single and three phase Dual Active Bridge converter both with simulation and experimentally. In the first phase of the thesis, as a case study, the single and three phase DAB converter are simulated in the PLECS software. The phase shift method has been implemented in order to control the converter. The operation frequency of the simulation is 5 KHz and the input and output voltage of the converters are 3KV and 6KV respectively. The transmitted power is 2MW. In the second phase of the project, the single phase dual active bridge has been implemented in the laboratory by using the dSPACE controller. The DAB converter has been tested for the frequencies of 50, 500 Hz and 1 KHz and for the maximum power of 0.5 KW. The maximum input and output voltage is 80 and 144 volts respectively. All tests for different voltage levels and frequencies have been done by simulation as well and the simulation results have been verified by the experimental results. The same tests also have been done for the three phase DAB converter which is implemented in the laboratory. These tests have been done for the frequency of 55 and 555 Hz and for the maximum power of 1.5 KW. The simulation results are also verified by the experimental results. In the last phase of the thesis, soft switching has been implemented by using snubber capacitors on both the single and three phase DAB converter and the results have been compared with the previous results. The highest possible frequency for the Single phase dual active bridge used in this thesis is 1 KHz and the highest possible frequency for the three phase case is 555 KHz by using the digital implementation of the dSPACE controller. The accuracy of the phase shift for the single phase DAB converter for the frequency of 1 KHz is 3.6 degrees and for the three phase DAB converter for the frequency of 555 Hz is 2 degrees. Loss calculation also has been done theoretically, for the simulation and also for the experimental tests. The results show that the implemented DAB converter has higher losses for higher frequencies. The implemented three phase DAB converter also has higher losses than the single phase one in this thesis due to the higher cabling and switching