Parallel connection of two single-phase ac-dc-ac three-leg converter with interleaved technique

This paper presents a reversible paralleled single-phase to single-phase dc-link converter which can be applied in line voltage regulator, power factor correction (PFC) and uninterruptible power supplies (UPS). It is composed of two single-phase three-leg ac-dc-ac converters with a leg shared by both load and grid sides. Suitable modelling and control strategy of the system are developed. A pulse width-modulation (PWM) technique based on a single and interleaved carriers PWM (double and quadruple carriers) is presented. Proposed topology permits to improve the harmonic distortion reducing the switching stress in dc-link capacitor and power losses. Generalized topology with N parallel dc-link converters is presented. Simulation and experimental results are also presented for confirmation of the performance of the proposed topology.