Comparative evaluation of load observers for a quadratic boost converter

Cascaded DC-DC boost power converters are topologies that have as main advantage their high voltage step-up ratio. This feature makes them suitable in applications, for instance, in non-conventional electric energy systems such as in photovoltaic, wind-turbine, battery and fuel cell applications, among others. However, the control of these power converters, commonly requires the computation of the voltage and current references. For some controllers, which are already reported in the literature, the knowledge of the value of the load is essential for operation in load-changing conditions. In this paper is addressed a comparative evaluation of three different load observers for the two stage, or quadratic, boost converter. Numerical simulations of each estimator and discussion about its performance are presented.