Summary Recently, with the development of electric vehicles (EVs), in order to compensate for the undesirable effects of charging stations on grid characteristics, paying attention to the local generators based on renewable energy has increased and has caused to develop of the peripheral systems. In this paper, a high step‐up multistage structure consisting of several integrated boost flyback converter (IBFC) has been proposed. In the combination of these stages, the boost subconverters are interleaved in order to charge the battery bank and are in series with the flyback subconverters in order to supply the variable loads. The proposed structure has advantages, such as applicability in high voltage step‐up cases, enhanced reliability in photovoltaic system, and flexibility against variable power consumption. In addition, this structure at the no‐load condition has the ability to charge the battery system with proper voltage and supply several vehicles simultaneously without any voltage drop. Furthermore, the energy stored in leakage inductor can be recycled instead of damping with passive snubbers, resulting in high conversion efficiency and simple circuit structure with fewer components. The performance of proposed structure is analyzed in detail at no‐load, loading, and input power outage conditions. Then, the proposed converter with solar panel input power in order to supply the EV charging system is simulated in Matlab/Simulink to verify the analytical results. Finally, a three‐stage prototype (17.3–240 V) with 60 W solar panel input has been developed, which validates the feasibility and the effectiveness of the proposed topology using variable loads (180, 360, 720 W).

This paper presents a new version of the incremental conductance algorithm for more accurate tracking of the maximum power point (MPP). The modified algorithm is called self-predictive incremental conductance (SPInC), and it recognizes the operational region. It is capable of detecting dynamic conditions, and it detects sudden changes in power resulting from changes in the intensity of radiation or temperature. By selecting the appropriate step size, it obtains maximum power from the panel at any moment. The improved algorithm reduces output power ripple and increases the efficiency of the system by detecting the operating area and selecting the appropriate step size for each region. The SPInC algorithm divides the system’s work areas into three operating zones. It calculates the size of the appropriate step changes for each region after identifying the regions, which allows for more accurate tracking of the MPP and increases the system efficiency at a speed equal to the speed of the conventional method. These additional operations did not result in a system slowdown in the tracking maximum power. According to the MATLAB/Simulink simulation results, the SPInC algorithm is more efficient than conventional InC, and the ripple output power is reduced. SPInC is also compared to the improved perturb and observe (P&O) algorithm. In general, SPInC can compete with the popular algorithms that have been recently proposed for MPPT in the other researches.

Summary This paper proposes a new adaptive clamp based on the hybrid operation of the interleaved two‐switch flyback micro‐inverter in one‐phase and two‐phase discontinuous conduction modes (DCM) depending on the output power of the PV panel. The proposed adaptive clamp controls the second switch of the two‐switch flyback structure based on the drain‐to‐source voltage spike of the flyback's main switch during the turn‐off process. Thus, in low‐voltage regions, a conventional flyback (single‐switch) operation is achieved with reduced switching, gate driving, and clamp diodes losses. Also, in the low output powers of the micro‐inverter, only one phase of the micro‐inverter operates to decrease the power loss associated with one phase. The theoretical analysis, simulation, and experimental results show the effectiveness of the proposed adaptive clamp and the phase control methods in improving the efficiency in all power ranges.

In the unfolding-type interleaved two-switch flyback inverter (ILTFI) operating in discontinuous conduction mode (DCM), the hybrid control strategy combining the one-phase DCM and the two-phase DCM has a significant impact on improving the efficiency under all load conditions. In the situation where the marginal power of this control strategy is increased, the converter may enter CCM. Consequently, the converter cannot track the reference current and the output current quality is notably decreased. To tackle this issue, a novel hybrid control method is proposed which varies the switching frequency based on the output power. The proposed approach is immune to the loss analysis and power losses of the components. Hence, it is independent of components selection and their characteristics. In this case, the smooth transition between the one-phase and the two-phase operation modes is guaranteed without affecting the output power quality and the stability of the converter in DCM. The control complexity of the proposed scheme is low and the converter can be easily controlled in DCM. The performance of the flyback microinverter with the proposed hybrid control scheme is verified by the simulation and the experimental results together with the loss analysis.

No abstract

This paper introduces a new fuzzy control system that is consisted of uncertainty to extract maximum possible power of wind. This system is based on fuzzy logic that can be tracked maximum power point of wind conversion system based on Permanent Magnet Synchronous Generator. In this type of fuzzy system determination of membership function is not with exact and membership functions are determined by a bound of operating.

A simple and efficient control structure of a flyback converter is proposed in this paper considering its intrinsic dynamic characteristics. The proposed control strategy makes use of a PI controller with a low pass filter to overcome the limitations on determining the gains of the feedback control system result from the right-half-plane (RHP) zero and LC filter dynamics. Therefore, the target output current is properly tracked and the disturbances are attenuated by the proposed control system. Furthermore, the stability requirements are satisfied and a zero steady-state error is obtained by appropriately regulating the control signal. This control method is very fast applying the minimum number of delays in its scheme which causes the computational burden to be significantly reduced. Finally, the theoretical claims are confirmed by simulation and experimental results on a 200-W laboratory prototype.