• Energy Research

AbstractWith the advancement of the application of power converters in the power industry, the research towards the prominent power converter namely multilevel inverter has gained a lot of attraction. Here, a dual‐source configured 11 level inverter topology is being discussed, which uses nine power semiconductor devices and one capacitor. The proposed topology is able to charge the capacitor up to 2Vdc which provides the boosting feature with the voltage gain of 1.67. An extended comparison with several other topologies has been provided which highlights the major contribution of the work. A low‐power laboratory prototype has been used for the validation of the proposed 11 level topology. Further, a thorough assessment of comparable topologies has been conferred in detail.

AbstractThis article proposes an interleaved high step‐up DC–DC converter topology designed for renewable energy applications, featuring an ultra‐high voltage conversion ratio. The converter employs an interleaved structure, resulting in a low peak‐to‐peak ripple in the input source current, which is particularly advantageous for solar PV sources. To enhance the output voltage, the topology utilizes voltage multiplier cells (VMC) and coupled inductor techniques. Two coupled inductors with three windings are integrated into the proposed topology, with the secondary and tertiary windings combined with VMC. This combination effectively reduces the maximum voltage stress across power switches, enabling the use of low‐rated and cost‐effective power switches for implementation. The article offers comprehensive operation modes and steady‐state analyses to demonstrate the converter's performance. A comparison is made between the suggested structure and other similar converter topologies. To validate the mathematical analysis, a 200‐W prototype is constructed, operating at a frequency of 25 kHz and achieving a voltage conversion range of 20 to 409 V. The experimental results are presented to support the findings.

Considering the aim of having low switching losses, especially in medium-voltage and high-power converters, the pre-programmed pulse width modulation technique is very useful because the generated harmonic content can be known in advance and optimized. Among the different low switching frequency techniques, the Selective Harmonics Elimination (SHE) modulation method is most suitable because of its direct control over the harmonic spectrum. This paper proposes a method for obtaining multiple solutions for selectively eliminating specific harmonics in a wide range of modulation indices by using modified Newton–Raphson (NR) and pattern generation techniques. The different pattern generation and synthesis approach provide more degrees of freedom and a way to operate the converter in a wide range of modulation. The modified Newton–Raphson technique is not complex and ensures fast convergence on a solution. Moreover, multiple solutions are obtained by keeping a very small increase in the modulation index. In the previous methods, solutions were not obtainable at all modulation indices. In this paper, only exact solutions to the low-order harmonics elimination for Cascaded H-bridge inverter are reported for all modulation indices. Analytical and simulation results prove the robustness and correctness of the technique proposed in this paper.

For a number of applications including the power processing of low voltage renewable sources such as solar PV in grid connected systems, high gain voltage conversion is a basic requisite. A conventional boost converter will have diode recovery issues, increased current ripples, poor transient response, and low efficiency if it is being operated at high duty ratio beyond certain permissible limit. This paper discusses a new converter suitable for the mentioned application that uses three double-duty regulated switches, switched inductor–capacitor to deliver the required high voltage at a low duty cycle. This converter’s basic topology does not include complex circuitry such as transformers, coupled inductors, and cascaded/interleaved configurations. In addition, the proposed converter can operate in auxiliary charging mode, which improves the voltage gain and control flexibility while also expanding the duty ratio range. The converter in discussion has a high voltage gain, a low total voltage standing, a continuous input current, a wide range of duty ratios, and the ability to select the duty cycle as needed. The boundary conditions, as well as the CCM and DCM investigations of the proposed converter are explored. The experiment findings are used to validate the claims made in the theoretical analysis. A comparison with the available high gain DC–DC converters is made to justify the superior performance. A 200 W prototype of the converter is developed and tested in laboratory to validate its feasibility and behavior for the renewable based applications.

At the present context, Plug-in electric vehicles (PEVs) are gaining popularity in the automotive industry due to their low CO2 emissions, simple maintenance, and low operating costs. As the number of PEVs on the road increases, the charging demand of PEVs affects distribution network features, such as power loss, voltage profile, and harmonic distortion. Furthermore, one more problem arises due to the high peak power demand from the grid to charge the PEVs at the charging station (CS). In addition, the location of CS also affects the behavior of EV users and CS investors. Hence, this paper applies CS investor, PEV user, and distribution network operator who could approach to CS's optimal location and capacity. Integrating renewable energy sources (RESs) at the charging station is suggested to lower the energy stress on the grid. Moreover, to keep down the peak power demand from the grid and utilize renewable energy more efficiently, energy management strategies (EMS) have been applied through the control of charging and discharging of the battery storage system (BSS). In addition, vehicle to grid (V2G) strategy is also applied to discharge the EV battery at charging station. Furthermore, the uncertainties related to PEV charging demand and PV power generation are addressed by the Monte Carlo Simulation (MCS) method. IEEE Scopus

The current paper is concerned with introducing a predictive polar flux control (PPFC) scheme for a variable speed wind driven doubly fed induction generator (DFIG) without speed sensor. The operation of the designed PPFC is based on the power angle regulation. The adaptation process is performed through studying the relation between the generator’s torque and the power angle between the stator and rotor flux vectors. A robust observer is designed based on the back-stepping theory to estimate the rotor speed, stator currents, rotor flux and stator and rotor resistances. Furthermore, an effective maximum power point tracking (MPPT) scheme is designed to achieve the optimal wind power exploitation. To recognize the operation of the schemed PPFC, a discursive performance evaluation is performed for the modeled control scheme and the classic predictive torque control (PTC) scheme. The achieved results report that the DFIG’s performance is effectively enhanced with the proposed PPFC in comparison with the PTC technique. The improved dynamics are observed through the ripples reduction and reduced switching frequency. In addition, the designed observer has successfully managed in estimating the specified variables with high precision.

A squirrel cage induction machine (SCIM) when aggregated with relevant capacitances and a prime mover, acts as self-excited induction generator (SEIG). As it hosts energy conversion the parameters of SCIM have considerable impact on the power extraction capability of SEIG. An aspect which is missing from the available research on SEIGs is evaluation of the affects of its rotor’s moment of inertia (J) and per-phase stator winding resistance (Rs) on performance indices. This work investigates the impacts of these factors on a SCIM’s performance as series compensated, short shunt SEIG. The study considers two distinctly designed SCIMs, in terms of J and Rs, operated as SEIG. In order to simulate their performance a stationary reference frame dq model including non-linear saturation and cross coupling effects is developed and verified experimentally. Several key investigations based on series capacitance selection, losses and efficiency, on-load performance with different power factor loads, transient performance with load perturbation and variable speed operation are carried out. The study reveals that SEIG with high J and lower Rsgives considerably better performance than its counterpart. The conclusions reported in the study are important especially for standalone/off grid application of SEIGs.