Hardware-in-the-Loop simulation of a complex AC-fed motor drive with triple active front-end 3-level rectifiers and induction motor drive using an intra-step-parallel state-space-nodal solver

This paper presents the Hardware-in-the-Loop (HIL) simulation results of a very complex AC-fed induction motor drive. The drive is composed of an AC-stage composed of 3 saturable zig-zag transformers in series, each connected to a 3-level NPC inverter and DC-link with RLC filter. The DC-link feeds another 3-level NPC-based induction motor drive and also comprises a precharge circuit. All switching devices of the circuit are controllable from the I/O points of the real-time simulator. Due to the high complexity of this drive and the requirement for full fault simulation capability, a new electric circuit solver called State-Space Nodal, based on state-space and nodal approach was used from within SimPowerSystems. The new algorithm is the first known example of an electric system solver algorithm that parallelizes the network equation on multi-core micro-processors without delays using computing threads. The use of parallel computing threads enables to gain up to 33% on computational time when compared to standard sequential execution of the same algorithm.