| Abstract |
This paper shows a current measurement technique, which combines approaches for synchronizedinverter current measurement with an advanced system of digital transmission and filtering of currentmeasurement values. The measurement technique gives a significant increase in performance,accuracy and robustness compared to classical measuring with sampled A/D conversion or notsynchronized techniques. This advantage is achieved by using a Delta-Sigma-Modulator for A/Dconversion and realization of signal evaluation with a sinc³-filter that is implemented in an FPGA.Additionally, the benefits in the precision and robustness of a new synchronized current samplingmode in combination with the digital processing and filtering of measured values are shown. Theevaluation of the signals and the control of the inverter system are realized by using an FPGA that ispart of the used dSPACE rapid control prototyping system. Digital signal processing and filtering arerealized with a new, for the use with the synchronized measurement technique, customized sinc³-filterstructure that gives best performance and efficiency in combination with the FPGA. A detailedimplementation of the technique is shown and the whole system is verified with a laboratory setup of acommon 2-level inverter system. |
