This paper aims to provide a comprehensive study of sliding mode controller (SMC) performance for closedloop voltage control of DC-DC three-cells buck converter based on hysteresis modulation (HM) where an adaptive feedforward technique is adopted. To fix the switching frequency, the approach is to incorporate a feedforward adaptive scheme which is effectively a variant of SM control. Further, the use of an adaptive feedforward control that makes the hysteresis band variable in the hysteresis modulator of the SM controller to restrict the switching frequency variation feeding parameters uncertainties and loads disturbance, in order to overcome the design constraints and to mitigate the undesired transient response. The results obtained under load change, input change and reference change clearly demonstrates a great dynamic response of the proposed technique, as well as provide stability in any operating conditions, the effectiveness is fast with a smooth tracking of the desired output voltage. Simulations studies in MATLAB/Simulink environment have been performed to verify the concept.

Introduction. This paper describes the simulation and the robustness assessment of a DC-DC power converter designed to interface a dual-battery conversion system. The adopted converter is a Buck unidirectional and non-isolated converter, composed of three cells interconnected in parallel and operating in continuous conduction mode. Purpose. In order to address the growing challenges of high switching frequencies, a more stable, efficient, and fixed-frequency-operating power system is desired. Originality. Conventional sliding mode controller suffers from high-frequency oscillation caused by practical limitations of system components and switching frequency variation. So, we have explored a soft-switching technology to deal with interface problems and switching losses, and we developed a procedure to choose the high-pass filter parameters in a sliding mode-controlled multicell converter. Methods. We suggest that the sliding mode is controlled by hysteresis bands as the excesses of the band. This delay in state exchanges gives a signal to control the switching frequency of the converter, which, in turn, produces a controlled trajectory. We are seeking an adaptive current control solution to address this issue and adapt a variable-bandwidth of the hysteresis modulation to mitigate nonlinearity in conventional sliding mode control, which struggles to set the switching frequency. Chatter problems are therefore avoided. A boundary layer-based control scheme allows multicell converters to operate with a fixed-switching-frequency. Practical value. Simulation studies in the MATLAB / Simulink environment are performed to analyze system performance and assess its robustness and stability. Thus, our converter is more efficient and able to cope with parametric variation.

This manuscript describes a comparative analysis between the variable-bandwidth (VBW) of the hysteresis modulation (HM) and the unipolar pulse-width modulation (PWM) by double intersection, both based on the conventional sliding mode (CSM) strategy. The two adopted techniques are applied to a new topology of a bidirectional asynchronous multichannel DC-DC Buck converter. The cells are parallelconnected and operating in continuous conduction mode (CCM).Our study contributes to the control method and the implementation, the command is applied at the same time without phase shift to an identical three cells of a non-isolated and asynchronous converter, this topology is rarely studied. The aim is to fix the switching frequency of the converter while referring to an adaptive feedback approach. Therefore, we integrate a hysteresis modulator and develop a variable hysteresis band function to attenuate the non-linearity phenomenon of the conventional sliding mode. Then, we apply an adaptive feedback current control technique to surpass the dilemma of the variable switching frequency for high power converters. The results demonstrate that the studied system became more stable, more efficient, and able to cope with variations in input voltage, load, and desired output voltage. The same results clearly show the areas where significant differences have been found between the two strategies. Simulation studies in the MATLAB® / Simulink™ environment are performed to analyze system performance and assess its robustness and stability under parametric variation.

Higher efficiency and lower losses are widely considered as the best metrics to optimize, in a high-power converter performance context. To provide a solution to the ever-increase of high switching frequencies challenges, we must explore soft-switching technologies to resolve interface issues and reduce the switching losses. This manuscript describes a comparative analysis between the fixed-bandwidth (FBW) and the variable-bandwidth (VBW) of the hysteresis modulation (HM) based on the conventional sliding mode (CSM) strategy. The two adopted techniques are applied to a bidirectional multichannel DC-DC asynchronous Buck converter. The cells are parallel-connected and operating in continuous conduction mode (CCM). The objective is to have a system that is more stable, more efficient and able to cope with variations in input voltage, load and desired output voltage. That requires, first, to attenuate the non-linearity phenomenon of the conventional sliding mode by placing a hysteresis modulation. Then, after applying this technique, we confronted the dilemma of the variable switching frequency. Our hypothesis was to incorporate a variable bandwidth of the hysteresis modulation. The results obtained under parametric variation clearly show the areas where significant differences have been found between the two approaches. Likewise, they both share several key features. Simulation studies in the MATLAB ® / Simulink ™ environment are performed to analyze system performance and assess its robustness and stability.

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