Three-Phase Sinusoidal Signal Generator with Harmonic Injection for Synchronous Reluctance Motor Control

This work aims to contribute to the development of control techniques for a Synchronous Reluctance Motor (SyRM) by improving a signal generator implemented in VHDL on an FPGA (Field Programmable Gate Array), where the output signals (PWM) generation will consist of a variable fundamental frequency and specific order harmonics, to attenuate noise in the motor’s current and torque signals (current ripple and torque ripple) during its operation. With a strong focus on controlling the torque signal harmonic content in SyRM, it is known that its ripple directly depends on components such as Carter’s factor, influenced by the magnetic permeability and geometry between the rotor, stator, and air gap, as well as the component generated by the SyRM magnetic flux. These components can be mitigated by improving rotor geometry with anisotropic structures. Another important ripple factor is the radial distance and stator geometry slots. The harmonic order identified through Fourier analysis of this signal is a reference for injecting noise-attenuating harmonics via PWM modulation. After assembling the signal generator and its components to generate the harmonics identified during SyRM operation, we simulated its performance and physically implemented the circuit, taking measurements on a passive, reactive load. By varying the injected harmonics, the switching frequency, and the operating frequency of the fundamental signal, we could observe the final signal composition as desired. These adjustments altered the working harmonics, the frequency range of the fundamental signal, the method of injecting and attenuating this signal, and ultimately achieved the goal of improving the efficiency of SyRM electric motors in terms of torque ripple.