Abstract
In this article, a novel partial electrical free measurement method to improve the power-factor of four-switch three-phase (B4) inverter for sensorless induction motor drives is proposed. This method uses a simple-free of measuring current or voltage for the power factor correction circuit. The proposed controller of the B4 inverter improves the power factor to be closed to a unity with a high power quality performance and with a minimum total harmonic distortion of the supply current. The complete drive system is carried out utilizing Matlab/Simulink. Also, it is executed in real-time using a prototype system composed of a dSPACE DS-1104 digital control board and a laboratory 1.1kW three-phase squirrel cage induction motor. The simulation and experimental waveforms prove the efficacy of the proposed drive system under various operating conditions. It is found that the proposed drive system has a reduced number of switches and sensors with a minimum cost which suitable for low commercial power applications. Moreover, it enhances noise isolation between power circuit and controller.