Nonlinear control of dc/dc power converters with inherent current and power limitation

Abstract

Abstract-A nonlinear controller with an inherent currentlimiting capability is presented in this paper for different types of dc/dc power converters (boost, buck-boost). The proposed controller is based on the idea of applying a dynamic virtual resistance in series with the inductor of the converter, which varies according to a nonlinear dynamical system. It is shown that the proposed approach acts independently from the converter parameters (inductance, capacitance) or the load and has a generic structure that can be used to achieve different regulation scenarios, e.g. voltage, current or power regulation. Based on the nonlinear model of the boost and the buck-boost converter, it is analytically proven that the inductor current remains always bounded below a given maximum value using input-to-state stability theory under a suitable choice of the controller parameters. Hence, the proposed control strategy offers an inherent protection property since the power of the converter is limited below a given value during transients or unrealistic power demands. Simulation results for both types of dc/dc converters are presented to verify the desired controller performance.

On Control of a Boost DC-DC Power Converter under Constrained Input

“…where and V were defined in (19) and (20), respectively, and = * + was defined in (24), it is possible to prove that the time derivative of W along the closed-loop system (27) is given byẆ…”

“…There, LMIs were used to insert the constraints in the design phase while imposing positivity 2 Complexity in the closed-loop state. Other problems with saturation in the dynamics (not in the system input) have been addressed in, for example, [20], where a nonlinear controller with an inherent current limiting capability was presented for different types of DC-DC power converters.…”

Current-Limiting DC/DC Power Converters

“…Although different current-limiting controllers have been recently designed for inverters and rectifiers [23], a generic concept for any type of dc/dc converter that achieves current limitation without suffering from integrator windup and instability has not been yet proposed. The proposed work introduces for the first time a framework that does not focus on a particular converter but is applied to a family of converters and is further extended to maximize power capacity utilization under faulty conditions, opposed to the existing previously mentioned techniques for rectifiers, inverters and specific types of dc/dc converters [24]. Extensive simulation and experimental results are presented to verify the desired operation of the proposed strategy and the current-limiting capability under both normal and abnormal conditions compared to existing current-limiting methods.…”

Bounded Control for DC/DC Converters: Application to Renewable Sources

“…Indeed, the technological progress and its rise in complexity of the required tasks, together with an always increasing demand of better performance, requires more advanced control methods. As a result, the development and application of control techniques different from the classic Proportional Integral Derivative (PID) for power converters is a well established research field, and its related literature is continuously enriched [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11].…”