Analysis of Dual-Carrier Modulator for Bidirectional Non inverting Buck–Boost Converter
A pulse-width modulation modulator for a non inverting bidirectional buck–boost converter is analyzed and a corresponding average-mode current controller design is revealed. The main feature of the modulator is the ability to create switching sequences for both converter legs without requiring any information regarding either operation mode or the direction of power flow. The modulator receives a control signal generated by the current controller, and a triangular carrier and generates driving signals with two different duty cycles, allowing tight control of the inductor current throughout the entire operating range.
Bidirectional converters are generally divided into isolated and nonisolated types. In the case where galvanic isolation is not required, a noninverting buck–boost converter is probably the most versatile topology, supporting BUCK, BOOST, and BUCK–BOOST operations.
The synchronous version of the converter allows bidirectional power flow. When a bidirectional noninverting buck–boost (BDNIBB) converter is voltage mode controlled(utilizing either hard or soft switching, the controller and modulator must be carefully designed to treat inherent nonlinearities and non smooth transients of mode transitions, which occur if the BUCK–BOOST operation is skipped to improve efficiency.
In this project, the modulator is generalized and extended to the average current-controlled bidirectional BDNIBB converter. Comprehensive analysis of the modulator operation is carried out and current controller based on the proposed modulator is designed.
It is shown that when the propose modulator is adopted, the control-to-output transfer-function gain of the current loop remains unchanged upon mode transitions and the corresponding plants differ only in terms of disturbance.
TOOLS AND SOFTWARE USED:
- MP LAB
Ilan Aharon, Student Member, IEEE, Alon Kuperman, Member, IEEE, and Doron Shmilovitz, Senior Member, IEEE, “Analysis of Dual-Carrier Modulator for Bidirectional Noninverting Buck–Boost Converter”, IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 30, NO. 2, FEBRUARY 2015.