Near Unity Power Factor Single-Phase to Three-Phase Converter Feeding an Induction Motor A. Maamoun*, A. M. Soliman* and A. M. Kheireldin** * Electronics Research Institute, El-Tahrir Street, Dokki, Cairo, Egypt Postal Code : 12622, Fax : 202-3351631, E-mail : [email protected] ** Faculty of Engineering, Ain Shams University, Cairo, Egypt Index Terms – Power converters, ac drives, power factor correction, harmonic reduction, pulse width modulation (PWM). Summary The conventional induction motor drive systems employ a rectifier-inverter structure consisting of a diode or thyristor rectifier, dc bus filter and an inverter. They have many drawbacks such as, high harmonic distortions and deterioration of power factor in the main supply. The paper presents a drive system consists of single-phase boost rectifier, space vector pulse width modulation (SVPWM) inverter, and three-phase induction motor. The single-phase boost rectifier is used to obtain near unity power factor and to reduce the harmonic distortion in the main supply. The SVPWM inverter is used to offer 15% increase in the output voltage and low output harmonic distortions compared with the conventional pulse width modulation (PWM) inverter. The boost converter is supplied from a full-wave rectified line voltage and operated so that the input current follows the input voltage. The input current shaping results in low line current harmonic distortion and a power factor close to unity at the interface between the ac line and the rectifier. The clamped-current boost rectifier is used as the proposed model for single-phase power factor correction (PFC) rectifier. Current-mode pulse width modulator is used to control the boost converter. The output dc voltage of the converter is regulated by voltage regulation loop where an error amplifier is used as a proportional –integral (PI) regulator. The output of the PI provides the reference current for the current control loop. The switch of the converter is turned on at the beginning of a switching cycle, and turned off when the switch current reaches the reference current, or when the switch duty ratio reaches the maximum duty ratio (0.5). The designed boost converter is used as a dc voltage source for SVPWM inverter feeding three-phase induction motor. The SVPWM enables to feed the motor with a higher voltage than the conventional PWM. The SVPWM allows to have a higher torque at high speeds, and a higher efficiency. The voltage/frequency control is used for open loop speed control of induction motor with a reasonable degree of accuracy. The input/output performance of the proposed model of single-phase to three-phase converter feeding an induction motor is investigated with different loading conditions.