**3. Hardware Setup**

#### *3.1. Real-Time Simulator And RT-Lab*

The processing unit of the digital twin is an OP4510 entry-level DRTS of OPAL-RT. Real-time computations are performed by a dedicated multi-core CPU capable of time step of 2 μs. For applications requiring smaller time step, one may rather opt for a higher-end DRTS or FPGA based platforms instead. Table 2 sums up the main technical specifications of the DRTS used in this work.


**Table 2.** Technical specifications of the OP4510 real-time digital simulator.

The OP4510 needs to be connected via an ethernet cable to a personal computer (PC) with RT-LAB installed. RT-LAB is a software environment for real-time simulation to interface with OPAL-RT's DRTS. Using a PC and RT-LAB, user can:


#### *3.2. Voltage and Current Measurement*

Measured voltages are the inputs of the model. Currents are also measured, but they are used for validation purposes to compare with the RTDT's outputs. A printed circuit board (PCB) was designed for voltage and current acquisition from the machine. The signals are then sampled using the DRTS's analog input channels.

## *3.3. Angular Position Sensor*

The angular position of the rotor is needed to retrieve the inductance matrix from the lookup table. It is measured using an absolute shaft encoder. The measured position is encoded in a 12 bits signal sent through a parallel communication interface. Each bit is acquired by a digital input channel of the DRTS and binary to decimal conversion is performed in software.
