This study proposes a non‐isolated quadratic boost converter (QBC) that features a low‐output‐voltage ripple with respect to traditional QBCs. This advantage is in contrast with other topologies that require a higher amount of stored energy by capacitors to achieve the same output‐voltage ripple specification. This benefit permits to design a compact converter, since the size of capacitors is proportional to their energy storage rating. Moreover, the proposed transformerless topology is suitable for applications that require high‐voltage gains as in the case of renewable energy applications. The main properties of the converter are corroborated as well as its advantages by providing mathematical models, analytical waveforms and experiments.

The conduction modes of the quadratic boost converter are explored in the context of high-dc-gain applications. A complete analytical description of the steady-state behavior of the converter operating in four possible inductor current discontinuous-conduction modes is presented. Boundaries between modes are determined together with the corresponding transitions. The study covers the operation of the converter using a pulse width modulator for constant switching frequency, and employing a hysteresis comparator for variable switching frequency. Both cases are analyzed for the same set of converter parameters and different constant resistive loads, while the converter is fed by a low dc voltage ranging from 20- to 30-V dc. Several simulations are used to verify the waveforms and average values predicted by the theoretical analysis. Experimental results in a 60-W prototype are in good agreement with the theoretical predictions, and efficiency measurements reveal that one of the discontinuous-conduction modes can compete with the continuous-conduction mode in high-dc-gain applications.

In this paper, output voltage regulation in a boost converter with constant power load (CPL) is carried out by means of sliding-mode control (SMC) with an estimation loop of the output power. The estimation procedure is based on the integral of an odd-symmetric function of the output voltage error, which confers an adaptive nature to the switching regulator. Rational, trigonometric, sigmoid and sign-type odd-symmetric functions are analyzed to select the best candidate for output power estimation. In addition, a two-degree polynomial surface is considered to induce the sliding motions. Subsequently, the corresponding conditions for the existence of the sliding mode and for the stability of the equilibrium point including the estimation dynamics are derived. One of the mainn features of this proposal is that the resulting controller can be implemented analogically, requiring operational amplifier-based circuits plus a divider. PSIM© and MATLAB© simulations show a fast recovery in response to large-signal disturbances in the load power and zero steady-state output voltage error. Experimental results obtained from a 500 W prototype are in perfect agreement with both theoretical predictions and numerical simulations.

This brief presents a control law based on a hybrid dynamical systems theory for a dc-ac converter. This theory is very suited for an analysis of power electronic converters, since it combines continuous (voltages and currents) and discrete (on-off state of switches) signals avoiding, in this way, the use of averaged models. Here, practical stability results are induced for this tracking problem, ensuring a minimum dwell time associated with an Linear–Quadratic Regulator (LQR) performance level during the transient response and an admissible chattering around the operating point. The effectiveness of the resultant control law is validated by means of experiments.

The unstable on and off state trajectories of a boost converter supplying a constant power load (CPL) are appropriately combined using sliding-mode control (SMC) with a suitable surface to yield a stable trajectory that reaches a specified equilibrium point. Selecting the optimum surface involves a comparative analysis among potential candidates in terms of stability, disturbance rejection, conduction losses and inrush current. The performance as switching function of polynomials of degree zero (non-zero constant), degree one (affine function) and degree 2 (quadratic function) are analyzed in depth to conclude that the affine function leads to the best static and dynamic results. The theoretical predictions are verified by means of simulations and measurements in a prototype.