Real-Time Loss Calculation of a Hysteresis Controlled Power Converter

This paper presents an algorithm for real-time calculation of losses of a hysteresis controlled power converter. The converter under consideration is a standard three-phase bridge converter, consisting of six insulated-gate bipolar transistors (IGBTs) and free-wheeling diodes. It is here utilized for vector control of a self-excited induction generator. The vector control algorithm requires measurement of two phase currents, rotor speed, and dc-link voltage. Application of the loss-calculation algorithm, on the other hand, requires knowledge of the dc-link voltage, one of the phase currents and IGBT switching signals. Hence, all three required inputs are already available, so no additional sensors need to be installed in order to implement the loss- calculation algorithm. The proposed algorithm allows the power converter losses to be determined both by type (switching/conduction losses) and device (IGBT/diode losses), thus enabling a more detailed loss analysis. In this paper, the power converter losses are determined over reasonably wide ranges of dc- link voltage and phase current values, and subsequently validated by comparison with the measured values.