Harmonic Analysis of a Regulated DC Voltage Space Vector Modulation Technique for High Speed Electrical Drives

In the field of high-speed electrical drives, the use of SiC MOSFET inverters represents a viable solution since this kind of devices allows an improvement of the converter efficiency. Notwithstanding issues related to the high frequency operation of the SiC MOSFET's, like the failure of the motor winding insulation due to the increased electrical stress and hence a reduced system reliability, are continuously arising. Additionally, SiC MOSFET's are much more expensive compared to equally rated Si IGBT's. A possible solution to keep on using a Si IGBT's based inverter in high-speed electrical drives is based on a particular version of the Space Vector Modulation that requires a regulation of the input DC voltage. The main advantage of such technique is the reduction of the power devices' switching frequency without lowering the motor control frequency. Hence, IGBT's can still be used and consequently it is possible to drastically reduce the stress on the motor winding insulation as well as the overall converter cost. To assess the real benefits of such approach, a detailed theoretical harmonic analysis has been carried out as well as an investigation on the implementation aspects. Finally, experimental results on a laboratory setup have been presented.