Sensorless speed control of BLDC motor drive using Volt/Hertz method

This paper presents a new sensorless speed control method for BLDC motors that combines the modified isolated Weinberg (MIW) DC-DC converter with a Volt/Hertz (V/F) control strategy. Using the V/F concept, the method eliminates the need for a commutation circuit and position sensors, which involve complex logic gates, simplifying the system. Keeping the voltage-to-frequency (V/F) ratio constant ensures minimal torque ripple, low steady-state speed error, and fast dynamic response, outperforming sensorless methods that struggle at low speeds. Including a switched inductor (SI) structure within the DC-DC converter boosts voltage gain and efficiency at various speeds. Compared to traditional methods, the V/F approach offers a more straightforward, robust alternative, providing smooth, reliable speed control without complex feedback loops. The proposed control scheme's performance is simulated using MATLAB/Simulink (2018a). The OPAL/RT simulator generates switching pulses for the inverter and isolated Weinberg converter. It validates BLDC motor results, confirming improvements in performance, energy efficiency, and system reliability, positioning V/F control as an effective solution for high-performance BLDC motor applications.