Five-phase EV Drive with Switched-Autotransformer (LCCAt) Inverter

The paper presents closed-loop electric vehicle (EV) drive with 5-phase induction motor operating with switched-autotransformer (LCCAt) inverter. Electrical drives with five-phase induction motors are considered for application in electric vehicles. Space vector modulation (SVM) is the most common option for controlling a five-phase inverter. However, if the battery level cannot ensure the controllability over a wide speed range of EV drive, the supply voltage has to be elevated. Bidirectional impedance source inverters (e.g. Z-source inverter, qZ-source inverter) have been presented suitable for EVs. The concept of Z-source/qZ-source inverters has been recently extended to transformer-based inverters (e.g. Trans-Z-source inverter, T-source inverter) which use coupled inductors with an appropriate turns ratio. Unfortunately, coupled inductors store significant portion of the energy during boost operation which tends their cores to saturate at higher currents. The use of four element LCCAt-source (inductor-capacitor-capacitor-autotransformer) network allows proposed switched-autotransformer inverter for obtaining high voltage gain while ensuring high modulation index and reduced volume of inductive elements. Simulation and preliminary experimental results using the laboratory model of switched-autotransformer inverter with designed 4.3 kW, 30V five-phase induction motor are shown to verify the effectiveness of the proposed system.