Fuzzy controller for dynamic performance improvement of a half-bridge isolated DC–DC converter

Design and dSPACE Implementation of a Simplified Fuzzy Control of a DC-DC Three-Level Converter

The design of an efficient DC-DC converter depends critically on its suitable control. In this paper, a new simplified output tracking control strategy for a DC-DC three-level boost converter is presented. The proposed strategy is characterized by its good tracking performances, its simplicity of design, and the stability that is ensured over the entire operating range. Thanks to (i) the adopted Takagi–Sugeno (TS) fuzzy approach; (ii) the small-signal model derived under the large domain of operating conditions, and (iii) the proportional-integral (PI) controllers’ merit. After introducing the three-level boost converter topology, the operating principles and mathematical modeling are addressed. Then, the proposed output control strategy is developed based on the PI control and the TS fuzzy approximation. A controller ensuring the capacitor voltages balancing has been also introduced in this paper. Experimental results using dSPACE (DS1104) and a laboratory prototype of three-level boost converter demonstrate the flexibility of the proposed controller, its reference tracking capability, and its ability to satisfy the performance specification over the whole operating range of the system.

A Compound Controller Design for a Buck Converter

In order to improve the performance of the closed-loop Buck converter control system, a compound control scheme based on nonlinear disturbance observer (DO) and nonsingular terminal sliding mode (TSM) was developed to control the Buck converter. The control design includes two steps. First of all, without considering the dynamic and steady-state performances, a baseline terminal sliding mode controller was designed based on the average model of the Buck converter, such that the desired value of output voltage could be tracked. Secondly, a nonlinear DO was designed, which yields an estimated value as the feedforward term to compensate the lumped disturbance. The compound controller was composed of the terminal sliding mode controller as the state feedback and the estimated value as the feedforward term. Simulation analysis and experimental verifications showed that compared with the traditional proportional integral derivative (PID) and terminal sliding mode state feedback control, the proposed compound control method can provide faster convergence performance and higher voltage output quality for the closed-loop system of the Buck converter.