Active capacitor voltage stabilisation in a medium-voltage flying-capacitor multilevel active filter

[摘要] A switching state substitution must be developed that will make use of both single-phaseredundancies and three-phase redundancies in the flying-capacitor topology. Losses shouldbe taken into consideration and the algorithm must be designed for implementation on theexisting PEC33 system, with on-board DSP (TMS320VC33) and FPGA (EP1K50QC208).The specific power-electronics application is a medium-voltage active filter.Existing capacitor voltage stabilisation schemes are investigated and a capacitor-voltagebased algorithm is developed that is investigated in parallel with the Donzel and Bornardalgorithm. Detailed simulation models are built for the evaluation of both existing and theproposed algorithm. Three-phase control is also evaluated.Timing analysis of the proposed algorithm shows that a DSP-only implementation of theproposed capacitor-based solution is not feasible. Detail design of the digital controllerhereof is implemented in VHDL. Finally, a four-cell controller is fitted into the FPGA. Ascalable hardware sorting architecture is utilised.

[发布机构] Stellenbosch University