ESTABLISHMENT OF AN FPGA-BASED REAL-TIME IM EXPERIMENTAL SETUP AND ONLINE IM MODEL VERIFICATION

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In this study, Serial Peripheral Interface (SPI) communication between the ADS 8568 EVM-PDK (Evolution Performance Development Kit) Analog to Digital Converter (ADC) developed by Texas Instrument and Xilinx XC5VLX110T FPGA board is implemented in order to verify Induction Motor (IM) model in real-time. Analog datas obtained from the voltage, current and torque transducers are converted to digital datas by ADC and read with FPGA simultaneously in real-time. Thus, the αβ- stator stationary axis components of the stator voltage ( and ) and αβ- axis components of the stator current ( and ) are calculated by Clarke transformation. The load torque  is obtained by passing the measured signals from the torque transducer through the low-pass filter which is implemented on the FPGA using 64-bit double floating number format. In addition, the signals obtained from the incremental encoder are read by the FPGA after the voltage level shifting with 74LS245P Integrated Circuit (IC), so that mechanical speed  (or ) of the rotor can be measured. All measurement algorithms except for the lowpass filter constructed for load torque measurement are implemented with VHDL by using 32-bit single floating numbers. The real-time verification of the rotor flux-based IM model is performed offline before it is implemented on FPGA by using the stator voltages, currents and load torque measured from the IM by using the simultaneous measurement unit in real-time. Thus, an FPGA-based real-time open-loop experimental setup of IM is established for the future works about the estimator/observer based speed-sensorless control of IMs.