Title: Modelling and Control of Non-isolated single-input multi-output (SIMO) DC-DC Converters
Time: 10.30 A.M
Venue: ESB 244
Speaker: Sreeshma M (EE16S012)
Guide: Dr. Arun D. Mahindrakar
Co-Guide: Dr. Ramkrishna Pasumarthy
Dr. Sridharan K (Chairperson) (EE)
Dr. Joel George M (AE)
Many battery operated portable devices, such as, LCD or CCD subsystems, mobile phones, digital cameras etc. include sub-modules that can provide different functionalities. These sub-modules demand power supply at different voltage levels and polarities. One way to build such supplies in an efficient way is to use multiport converters. For example, single-input-multi-output (SIMO) converters could be configured to obtain output voltages at different levels and polarities. Conventional implementation of a SIMO converter requires separate inductors and switches for each of the outputs. This is a hindrance when used in battery operated portable devices as they have size constraints. Non-isolated SIMO converters with single inductor and single switch can be used to overcome this hindrance.
In this work we focus on the modelling and control of non-isolated SIMO converters with the Zeta- Buck-Boost (ZBB) converter as an example. The difficulties in modelling non-isolated SIMO converters arises due to the switching among multiple differential algebraic equations (DAEs) governing the circuit. This is addressed by using the ideas of quasi Weierstrass transformation and flow matrix to get an averaged ordinary differential equation (ODE) model of the converter. It is verified through simulations that the model derived from the above method accurately captures the averaged steady-state and the transient behaviour of the ideal converter.
It is observed that the algebraic constraint governing the converter, gives rise to an uncontrollable mode in the averaged model. The controllable subsystem is used to design a linear state-feedback controllerwith integral action for the task of line regulation. We see that, although line regulation is successfully achieved, there are large deviations from the set-point in the transient phase.This leads us toexplore a non-linear controller based on Lyapunov redesign technique. A hardware setup of the ZBB converter is built to test the effectiveness of the averaged model and working of proposed control schemes.
All are cordially invited.