Loss Calculation in a 3-Phase 3-Level Inverter Using SimPowerSystems and Simscape

SimPowerSystems(SPS) and Simscape are used to calculate losses in a 3-phase, 3-level inverter.

From a +/- 1800 volts DC source, a 400-kW, 3-phase 3-level inverter delivers variable power to a
distribution power system. The inverter output is connected to the 25-kV, 40 MVA, 50-Hz system
through a 2200 V / 25 kV transformer.

Each 3-level leg of the 3-phase 400-kW inverter comprises three commercial half-bridge IGBT modules. Phase-A leg is implemented using the “Half-bridge IGBT with Loss Calculation” block provided in a SPS local library. Based on the thermal characteristics of the selected IGBT module, both switching and conduction losses are calculated. Thermal blocks of the Simscape foundation library are used to model the heat dissipation provided by the heat sink. The simulation illustrates the achievable output power versus switching frequency for the 3-phase, 3-level inverter and compares results with the manufacturer’s reference document.

A Help file containing useful information on the model is also included.

Authors: Pierre Giroux, Gilbert Sybille, Olivier Tremblay
Hydro-Quebec Research Institute (IREQ)