Measurement of High Frequency Impedance Characteristics for Induction Machine at Zero Stator Frequency by using FPGA

This paper reports the measurement results of the high frequency (HF) impedance characteristics using FPGA for the purpose of improving the low speed and regenerative operation performance, including zero stator frequency, for the induction machine (IM) sensorless drive. HF impedance is measured from the amplitude ratio of the injected HF voltage reference to the measured HF actual current. The FPGA is used to extract the amplitude of the HF current. The amplitude of the extracted HF current is taken into the digital signal processor (DSP), then the HF impedance is calculated with the amplitude of the HF voltage reference. As a result, the measurement results of HF impedance characteristics at various injection signals using FPGA are shown. In addition, the measurement results assuming real-time detection of HF impedance are shown to confirm the effectiveness of fast sampling using FPGA.