OBSERVER BASED POLE PLACEMENT AND LINEAR QUADRATIC OPTIMIZATION FOR DC-DC CONVERTERS

Abstract

A thorough and effective analysis of the DC-DC converters is carried out in order to achieve the system stability and to improve the dynamic performance. A small signal modeling based on state space averaging technique for DC-DC converters is carried out. A state feedback gain matrix (control law) and a full order state observer (which estimates all the state variables) are designed by pole placement technique in order to achieve the stability of a completely controllable system. Using Separation Principle, state feedback matrix and the full order state observer are combined together to provide a dynamic compensation for the dc-dc converters. The state feedback matrix is optimized using Linear Quadratic Optimal Regulator method based on Riccati matrix which further improves the system performance. The analysis and operation are investigated and verified through simulation. When compared with the conventional PID controller and other existing methods the output responses obtained by these methods are very much improved with zero output voltage ripples, zero peak overshoot, much lesser settling time in the range of ms and with higher overall efficiency (>90%).