This work deals with a new integrated EV on-board fast charger with interleaved boost AC-DC converter at the front-end followed by a half-bridge partial power processing (PPP) converter at the DC-DC stage. The main objective is to improve the converter power density and efficiency compared with conventional integrated chargers that employ a full power processing converter (FPP). The AC-DC stage is obtained using the inverter switches and the electric motor windings as part of interleaved boost rectifier at front-end. The DC-DC stage is based on a half-bridge configuration with partial power processing, reducing the power processed by the converter significantly. The proposed topology has a minimal number of components and ensures that most of the charging power passes directly through the rectifier DC-link reducing the number of conversion stages in the charger. The partial power conversion (PPC) design further helps in achieving smaller rated devices in the converter due to differential voltage applied as per the PPP concept. The design of the converter is discussed in detail and the performance of an 11kW charger is simulated using MATLAB/Simulink and compared with that of FPP DC-DC converter-based integrated chargers published in the literature. The operating characteristics of the proposed partial power conversion scheme are experimentally verified using a 3.3kW laboratory setup, achieving a peak experimental efficiency of 97.25%.

DC-DC converters employed in fuel cell vehicles (FCVs) are expected to demonstrate characteristics such as a wide voltage gain range, low input current ripple, and high voltage gain. To meet these specifications, this paper proposes a hybrid DC-DC converter comprising an active switched inductor (ASL) cell, a switched capacitor (SC) cell, and a zero current ripple (ZCR) cell. The proposed converter achieves high voltage gain, wide voltage gain range, low switch current and voltage stresses, and near zero input current ripple. The SC cell supports the output capacitor of the switches during the OFF periods, decreasing switch voltage stress and further enhancing voltage gain. The ZCR cell helps reduce input current ripple and lowers current stress in the switches. The paper includes a discussion on the operating principles of the proposed converter, steady-state analysis, parameter design consideration, closed-loop controller design and a comparison with other hybrid ASL-SC high-gain DC-DC converters. Finally, a 720W laboratory prototype is built and tested. Experimental results are presented to verify the operation of the proposed converter. The closed-loop performance is also validated experimentally under load and input voltage variations.

This paper presents a new dual-duty triple switch (DDTM) high-voltage gain DC-DC converter topology for DC microgrids. The proposed DC-DC converter integrates a modified active switched inductors (mASL) cell with a symmetrical switched capacitors (SSC) cell to achieve very high voltage gain and very low voltage stress. The mASL cell incorporates a unidirectional switch across the inductors of the conventional ASL cell, enabling dual-duty triple-mode operation. This feature adds flexibility in achieving the desired output voltage using different combinations of duty cycles. The SSC cell of the proposed converter not only enhances the voltage gain but also suppresses voltage oscillations in the ASL cell, resulting in reduced voltage stress across the switches. The operating principles, steady-state analysis, and comparative evaluation are provided. Finally, the performance of the proposed converter is validated using a laboratory prototype (24V/318V).

This paper proposes a hybrid dynamic voltage restorer topology aimed to reduce the power rating requirements for a DVR used as a fault ride-through support for a wind turbine generator. An auxiliary dissipation resistor is employed during fault conditions to absorb some of the power generated by the turbine and reduce the DVR power evacuation burden. The design reduces the required power rating of all the DVR's components significantly. A stator voltage control scheme is proposed to ensure voltage support under symmetrical fault conditions. The performance of the proposed topology was evaluated using PSCAD/EMTDC and compared with the conventional DVR voltage restoration circuit. The results confirm that the proposed scheme successfully maintains the stator voltage at pre-fault levels while utilizing a substantially lower-rated DVR.

A bidirectional four-switch buck-boost (FSBB) converter offers more control variables than a classical buck-boost converter and can thus achieve higher power efficiencies through appropriate control. Traditionally, efficiency is optimized by reducing the inductor current rms value (or conduction loss) obtained through time-domain analysis. However, it is extremely difficult to use this time-domain approach to include converter switching losses in the efficiency optimization for all possible modulation modes. To solve this problem, this article proposes a frequency-domain analysis to estimate switching losses and establish a comprehensive loss model that allows for the efficiency to be optimized using a Gaussian quantum-behaved particle swarm optimization (GQPSO) algorithm. The switching frequency is then used as an additional optimization variable to improve the efficiency over a much wider range of operating conditions. The proposed method is verified experimentally, using 600 and 1500 W rated laboratory prototypes, and compared with existing methods. Results demonstrate the effectiveness of the proposed technique in increasing converter efficiency over the whole range of load conditions.

n response to the growing adoption of 800V electric vehicles (EVs), which offer significantly faster charging capabilities, the onboard charger (OBC) must be adapted to handle higher voltage levels efficiently. Modern OBCs are increasingly expected to support not only grid-to-vehicle (G2V) and vehicle-to-grid (V2G) power transfer but also additional functions to enhance system integration and performance. This paper proposes a novel OBC topology derived from the conventional H-bridge converter architecture. Beyond enabling bidirectional G2V and V2G operations, the proposed design also supports high-voltage to low-voltage (H2L) power transfer, allowing energy delivery from the main traction battery to the auxiliary low-voltage battery. Compared to traditional OBC configurations, the proposed topology significantly reduces the number of active switches, leading to advantages in terms of system volume, cost, and complexity. The feasibility and performance of the proposed converter are validated through detailed simulations conducted using PLECS software.

The accurate estimation of solar irradiance probability distribution is essential when assessing the level of available solar resources and attempting to minimize the effect of solar power variability on power system planning. The Beta distribution has long been a popular choice in power systems for modeling solar data. The use of parametric models, however, has been shown to be problematic and can lead to model mis-specification. This article proposes an adaptive hybrid model combining the Beta distribution with the Kernel Density Estimation (KDE) approach for solar irradiance probability density estimation, in which the weights of the two components of the hybrid model are adjusted using the least mean square algorithm to obtain the most appropriate combination. The hybrid model is evaluated using multi-year data at six different sites in the United States. The assessment is carried out using the Kolmogorov-Smirnov goodness-of-fit test, coefficient of determination ( $R^{2}$ ), and two error measures: Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). By combining parametric and nonparametric approaches, the adaptive model achieves a better fit and substantial improvements in all metrics when compared with the Beta distribution and other statistical models. The proposed hybrid estimator is the only model for which the null hypothesis is not rejected for all considered datasets. In terms of the statistical metrics, percentage improvements of up to 92.2% ( $R^{2}$ ), 30.6% (MAE), and 26.6% (RMSE) were achieved when compared with the Beta distribution results. Similarly, when compared with the threshold-based model, percentage improvements of up to 32.7% ( $R^{2}$ ), 20.6% (MAE), and 16.0% (RMSE) were obtained.

Triple switch, triple mode (TSTM) dc-dc converters find extensive utilization in renewable energy applications. Unlike other dc-dc converters, TSTM converters operate with two duty cycles (d, d(1)), achieving maximum power point tracking (MPPT) and output voltage regulation simultaneously. However, these converters often exhibit high voltage stress on the switches due to resonance caused by mismatched switch/inductor parameters. This article proposes a new TSTM dc-dc converter for high voltage gain with low voltage stress. The advantages of the proposed converter include the following: 1) elimination of resonance due to parameters mismatch, resulting in the suppression of voltage oscillations, 2) flexibility to regulate the output voltage with two duty cycles, and 3) high voltage gain over a wide range of duty cycles. The article provides a detailed explanation of the converter topology, working principle, steady-state analysis, external characteristics, and closed-loop controller design. The design guidelines and performance comparison are also presented. A 460-W laboratory setup is built, and experimental verification is conducted for the voltage conversion from 24 to 272 V.

A bidirectional isolated dc—dc converter is normally employed in on-board charger (OBC) circuits to extend the output voltage range of the power factor correction (PFC) converter because the latter alone cannot meet the electric vehicle (EV) battery charging voltage range. The isolated dc—dc converter also prevents faults propagating from one side of the circuit to the other side and prevents the flow of leakage currents during charging, which is important for safety considerations. Because the capacitor has a higher energy density than magnetic elements, this article utilized a capacitively isolated dual-active bridge (CDAB) converter to provide isolation in the OBC. Specifically, two low equivalent series resistance (ESR) film capacitors are used to replace the transformer in the traditional dual active bridge (DAB) converter. A comprehensive analysis of the operating modes of the converter, based on single phase shift control, is presented together with a discussion of converter design parameters. A 1 kW laboratory prototype is constructed to experimentally verify the proposed topology. Compared with the conventional DAB and CLLC converters, the proposed CDAB converter has a higher power density and improved efficiency, confirming the superiority of the proposed topology.

Range anxiety is one of the main problems for electric vehicles (EVs) due to low battery power density and low charging speeds. The charging speed can be improved by increasing the charging power. The maximum charging power can be increased by raising the battery voltage level from 400V to 800V. However, if the number of new 800V DC fast charging piles cannot increase quickly, charging will become a new problem for 800V EVs. To solve this problem, a method is proposed to allow the 400V charging station to charge the 800V EV. The motor winding and inverter are used to form a boost converter that connects to the 400V charging station through the DC charging port of EVs. With one additional switch, the proposed method can be compatible with 400V and 800V charging piles. The proposed method is verified by simulation and a 500W laboratory prototype.

The nominal behaviour of a DC chopper fed DC drive under proportional integral (PI) control is a periodic orbit whose period equals that of the clock. But as some controller parameters are varied, this nominal orbit loses stability via a Neimark-Sacker bifurcation leading to the birth of a quasi periodic orbit (the so called torus) with a considerable impact on the losses and lifetime of the system. Further variation of the system parameters leads to several period-adding, phase-locking and chaotic phenomena as the torus breaks down. In this paper, by employing the Monodromy matrix, we were able to determine analytically when this occurs, and hence appropriate action can be taken when the controller is designed. Analytical and numerical results validate our findings.

In this article, we propose an improved high-boost-gain split-source inverter (SSI) for renewable energy generation. The proposed inverter retains the features of the existing SSIs, such as single-stage boost inversion with a reduced number of passive components and elimination of the inverse modulation–duty relationship constraint of the impedance-source inverters. It also provides additional features that include higher boost inversion ability than existing SSIs to connect low-voltage renewable energy sources to the grid, no voltage-source short-circuit issue, which increases the robustness of the proposed inverter and pulsewidth modulation dead times can be relieved, and the negative input dc-terminal and ac-neutral are electrically connected in the proposed inverter, resulting in a constant common-mode voltage and elimination of leakage ground currents for grid-interfaced PV power systems. A detailed circuit operation and analysis is provided, and experiments are performed on a 400-VA prototype inverter to confirm the working of the proposed topology.

A wireless charging using wireless power transfer (WPT) technique is the future of electric vehicles (EVs). With the implementation of wireless charging, efforts on modifying the plug-in EV charging infrastructure compatibility could be reduced. WPT system basically works on the principle of electromagnetic induction. WPT has basic two types, inductive power transfer (IPT) and magnetic resonance coupling (MRC) power transfer. For a conventional IPT, two-stage structure is one of the most common topologies, of which the efficiency will be dramatically decreased by a cascaded dc–dc converter. To overcome the issue, in this paper, various partial power processing (PPP) converter (PPPC) architectures for wireless chargers are shown and a detailed analytical evaluation of S-S and LCL-S compensated topologies is given. With PPP based architectures, the system efficiency is improved, and the converter size is reduced. The WPT receiver is divided into the main receiver and the auxiliary receiver, i.e. dual receiver. Most of the power is transferred to the load through the main receiver, whereas the auxiliary receiver is used to regulate the output voltage. As a result, the switching loss and device stress of the dc–dc cascaded at receiver can be significantly reduced.

This letter deals with a single-phase, nonisolated on-board charger (OBC) for electric vehicles (EVs) based on a four-switch three-port (FSTP) converter topology with a power decoupling function. However, in the published literature, the size of the decoupling cell (inductor and capacitor) is generally large, making promotion and application challenging. To minimize the decoupling cell size, an improved power decoupling control method is proposed in this letter. Specifically, the decoupling cell inductor current reference value is generated by using the output of a proportional integral (PI) plus proportional-resonant (PR) controller so that the decoupling cell can absorb double-line frequency power to the maximum extent. The proposed control method is implemented in a 500Wlaboratory prototype. Compared with the existing control method, under the same operating condition, the proposed approach reduces the output direct current (dc) voltage ripple by 71.2%, the decoupling capacitance by 40%, and the decoupling inductance by 66.6%.

The on-board charger (OBC) of an electric vehicle (EV) is desired to perform many functions, such as transferring power from the grid to the vehicle (G2V), transferring power from the vehicle to the grid (V2G), and so on. To meet these requirements, a topology based on a four-switch three-port converter is proposed in this paper. In addition to the G2V and V2G functions, the proposed converter can transfer power from the high-voltage battery to the auxiliary low-voltage battery (H2L). Compared to the traditional OBC topology, the proposed circuit has a lower number of switches, reducing the cost of the system. Simulation results using PLECS software to demonstrate the effectiveness of the proposed topology.

Active switched inductor (ASL) DC-DC converters utilize parallel charging and series discharging of inductors, which improves the voltage gain. In practice, the inductors often have unequal values, leading to variations in instantaneous currents when switching from parallel charging to series discharging. This leads to an increase in voltage stress across the switches of ASL cells. This paper proposes a symmetrical ASL hybrid DC-DC converter, providing a current path of the inductor currents when circuit configuration changes from parallel charging and series discharging of inductors, lowering the voltage stress. The operating principle, design equation, and device stress are analyzed. Finally, a laboratory prototype (22/308V) generating 430W is developed and tested to validate the analytical analysis.

Vehicle-to-vehicle (V2V) energy sharing is an approach that can help alleviate the range anxiety of electric vehicle (EV) drivers because it can solve the “last kilometer” problem that can prevent an EV with a low charged battery arriving at a destination or a charging station. V2V chargers utilizing the motor winding and inverter are preferred because they can achieve higher transmission powers at no extra cost. However, compared with onboard chargers that use isolation transformers to share energy between vehicle and vehicle, these converters (that make use of the motor winding and inverter) provide no isolation and cannot stop the propagation of a fault from one vehicle to the other. To solve this problem, a capacitor-isolated V2V converter that utilizes the drive motor winding and inverter is proposed in this paper, based on the principle of capacitor isolation in the gate driver chip. A 400W laboratory prototype is used to experimentally verify the performance and feasibility of the proposed method.

Probability density estimation of stochastic electric load is of importance nowadays in power system operations and urban planning due to the uncertainties in network demand that affects the operating states of power systems. This in turn requires accurate and reliable methods to estimate network loads, especially in distribution networks. This paper proposes employing the root-unroot method in combination with local linear regression for estimating electric load probability density. Using measured load data obtained for a range of commercial enterprises, the performance of the proposed model is compared with two kernel density estimation models and two traditional parametric models (Gaussian and Gamma) and is assessed using a variety of error metrics and statistical tests. Results confirm the accuracy of the nonparametric models over the parametric models with the root transform model performing the best across all error metrics and K-S goodness-of-fit test.

Precise estimation of available wind speed at a certain location is of paramount importance when planning and designing power distribution networks. Parametric Families of Probability Distributions (PFPDs) have been popular choices in the literature. These, however, apply certain assumptions that are too restrictive and may often end up in wrong model identification. To mitigate these limitations, Nonparametric Family of Probability Distributions (NPFPDs), such as the Kernel Density Estimation (KDE), have been considered in recent power systems studies. In this article, three popular PFPDs (Rayleigh, Weibull and Gaussian), and two recently suggested PFPDs for power systems studies (Birnbaum-Saunders and Nakagami-m) are assessed and compared with the KDE approach using Ruleof-Thumb (ROT) for bandwidth estimation. The resulting probabilistic wind speeds are then used to estimate the productivity of the wind turbine by means of energy yield. Results show that PFPDs produced high error values; leading to inaccurate decisions when conducting power systems planning studies. In contrast, the KDE-ROT estimator achieved the lowest estimated absolute error. As such, nonparametric approaches present better candidates for accurately estimating wind turbine energy.

The widespread use of three-phase cage induction motors in so many critical industrial, commercial and domestic applications means that there is a real need to develop online diagnostic systems to monitor the state of the machine during operation. This paper presents a hybrid diagnostic system that combines a model-based strategy with a fuzzy logic classifier to identify abnormal motor states due to single-phasing or inter-turn stator winding faults. Only voltage and current measurements are required to extract the fault symptoms, which are represented as model parameters variations in an equivalent virtual healthy motor, negating the need to use complex models of faulty machines. A trust-region method is used to estimate the machine model parameters, with the final decision on the type, location and extent of the fault being made by the fuzzy logic classifier. The proposed diagnostic system was experimentally verified using a 1.0 hp three-phase test induction motor. Results show that the proposal method can efficiently diagnose single phasing and inter-turn stator winding faults even when operating with unbalanced supply voltages and in the presence of significant levels of measurement noise.