Input DC Source Research Articles

Multiple‐Input and Multiple‐Output–Based Cascaded Boost Hybrid Interlink Converter

ABSTRACTThe multiple‐input and multiple‐output (MIMO) DC–DC converters offer various advantages such as improved efficiency and reduced component count. However, the preference of these converters over other types of converters is dependent on the specific application and requirements. Various types of boost‐derived MIMO DC–DC converters are discussed in the literature. However, these converters are either nonisolated or isolated types. In the paper, a MIMO‐based cascaded boost hybrid interlink converter (CBHIC) has been proposed. The proposed converter includes four DC–DC boost converters that are supplied power by two input DC sources. The boosted DC output of these converters can be used independently or in a cascaded manner depending upon the requirement of the load. Further, the cascaded action of these four boost converters leads to the production of two high‐frequency AC outputs. By using bridge rectifiers and high‐frequency transformers, high‐frequency AC voltages are converted into DC. Therefore, two isolated DC output voltages can be achieved using CBHIC. The complementary operation of the cascaded boost converters results in reduction of source current ripples. The design, operating modes, and performance evaluation of the proposed CBHIC have been included in the paper. To validate the efficacy of the proposed CBHIC, a lab prototype of 400 W is prepared. The rms value of high‐frequency AC output voltage at each is isolated port is 141 V. The CBHIC exhibits an efficiency of 94.3 at 400 W. The operation of the converter during voltage control mode is further explored and its dynamic response is studies with the help of experimental results. The obtained simulation and experimental results validate the effectiveness of the proposed converter.

A modular multiport Landsman converter-driven hybrid EV charging station with adaptive power management system

This article presents the implementation of a hybrid charging station that utilizes renewable energy sources to power its operations. The core of this system is a modular multiport Landsman converter, which serves as the interface between diverse renewable sources, including photovoltaic panels, wind turbines and fuel cells. A sophisticated multi-agent-based energy management system is employed to address the intermittency of renewable energy supply throughout the day. Additionally, a fuzzy logic controller (FLC) facilitates the seamless charging of electric vehicles within the system. The FLC detects the state of charge (SoC) of the vehicle's battery and the battery present in the station, enabling efficient EV charging. The multi-agent energy management system with load shedding controller (MAEMLS) and FLC continuously monitor the power availability, power demand, charging time, and charging duration of the charging station. This approach reduces the charging rate for EV owners during peak demand periods. The proposed system is modelled and tested using MATLAB/SIMULINK software, and a laboratory prototype has been constructed. The results demonstrate that the anticipated converter is highly suitable for integrating hybrid energy sources and charging electric vehicles (EVs). Notably, this converter exhibits an efficiency ranging from 85 %-95.05 %, based on the availability of input DC sources.

Finite‐time control of DC–AC boost converter: The limit cycle approach

AbstractThis paper proposes a novel finite‐time limit cycle controller for DC to AC conversion in power boost converters. The stable limit cycle is categorized as a positive limit set. Achieving the control law, based on the concepts of set stability and finite‐time stability, is a challenging problem. To fulfill the control objective, a novel sliding manifold is suggested concerning the structure of the wanted limit cycle which facilitates conditions for the development of finite‐time stability for the limit cycle. By utilizing the sliding mode control method, a control strategy is proposed that guarantees the desired stable limit cycle is created in the phase plane of the closed‐loop system and the phase trajectories reach it in a finite time and remain on it for all future times. This ensures the finite‐time generation of the biased sinusoidal oscillations in the output of the power boost converter from a DC input source. The simulation results of a practical boost converter have validated the effectiveness and feasibility of the presented algorithm.

A new method for selecting optimum levels in asymmetric Cascaded H‐Bridge‐Multilevel Inveter with variable DC sources

SummaryIn general, cascaded H‐bridge multilevel inverters (CHB‐MLI) are typically operated with either symmetrical or asymmetrical input DC sources, set at predefined specific ratios such as binary (1:2) or trinary (1:3) in the case of asymmetry, to achieve the desired output voltage waveform. However, if any DC source fails to provide the predefined voltage magnitude, or CHB‐MLIs with unspecified DC source ratios are utilized, the output voltage waveform may exhibit unequal magnitudes between consecutive levels, thereby causing a significant increase in total harmonic distortion (THD). Conventionally, to mitigate this effect, the corresponding H‐bridge is bypassed through zero voltage switching, which leads to an additional burden on the remaining H‐bridges to serve the same load. To reduce the burden on the remaining cells and improve the THD profile of the inverter, this article proposes a novel method for CHB‐MLI with varying DC magnitudes. It aims to enhance the quality of the output voltage waveform by strategically selecting optimum voltage levels rather than utilizing all available levels when CHB‐MLI has unspecified or variable DC sources. This approach can achieve a more balanced distribution of voltage magnitudes across successive levels by eliminating redundant states. Moreover, the proposed technique can reduce switch losses and enhance the converter's efficiency. The proposed method is validated through MATLAB/Simulink software simulations, followed by experimental verification.

Performance evaluation of novel 9-level RSMLI topology for grid-tied solar-PV system

The shortage of traditional fossil fuels like coal, petrol and natural-gas are increased day-by-day, fulfills the most of energy demand. Most of engineers are trying to maximize the energy demand by employing renewable energy with existing micro-grid system. Owing to merits, the solar-PV system plays a significant alternative among all other renewable energy sources due to abundant and virtuous nature. For grid-tied solar-PV system, the cascaded H-bridge multilevel inverter is the most significant over the classical 2-level inverter due to provision of isolated input DC sources. But the cascaded H-bridge topology is designed for limited voltage levels due to its larger number of switches for higher voltage levels, high cost, large-size, and more weight. To alleviate these demerits, a reduced-switch multilevel inverter has been generally preferable for higher voltage levels. In this work, a novel 9-level reduced-switch multilevel inverter (RSMLI) topology has been proposed by utilizing low number of switching devices. The performance of proposed novel 9-level RSMLI topology has been verified in grid-tied solar-PV system by using MATLAB/Simulink tool, simulation results are presented with attractive comparisons.

An integrated common ground‐based grid‐connected current‐fed switched inverter

AbstractA current‐fed switched inverter and its derivatives are gaining more attention in solar PV grid‐connected applications. In these inverters, the absence of galvanic isolation generates the leakage current, leading to the injection of harmonics and the degradation of solar PV panel life span. This paper proposes an integrated common ground‐based grid‐connected current‐fed switched inverter. The common ground between the input DC source and output AC grid eliminates the leakage current and makes the inverter immune to high‐frequency common‐mode voltage variations. It utilizes the shoot‐through state to boost the input DC voltage and obtain the rated AC output voltage. Moreover, as compared to the contemporary common ground‐based inverter topologies, the number of passive reactive elements and active switches is less. Thereby, the size, cost of the system, and associated power loss are reduced. The proposed inverter's continuous input current and buck–boost nature make it suitable for applications like solar PV systems. The steady‐state analysis of the proposed inverter is validated using the MATLAB Simulink tool, and furthermore, the simulation results during grid‐tied mode have been cross‐verified with the help of real‐time simulator OPAL‐RT. Further, the power loss and thermal loss analysis are carried out using the PLECS software. Finally, the performance of the inverter and simulation results are verified with the experimental results.

A New Five-Level Switched-Capacitor-Based Transformer-less Common-Grounded Grid-Tied Inverter

This paper proposes a new switched-capacitor grid-tied inverter. The proposed topology can eliminate leakage current using a common-grounded strategy. Also, the proposed topology generates a five-level output voltage waveform using a single input dc source with a voltage boosting factor of 2. This structure uses six power switches, two diodes, and two self-balanced capacitors. The proposed inverter has some advantages such as a common-grounded feature, eliminated leakage current, and voltage boosting feature with single-stage energy conversion operation. Also, the proposed topology can support both active and reactive powers and generate a perfect sinusoidal output current injected into the grid. Also, to control both active and reactive powers an efficient control strategy is applied. To generate the precise gate pulses for the power switches, the introduced efficient control strategy is applied. Also, comprehensive discussions on the operating modes of the proposed inverter, Capacitor charging current analysis, the control technique, and design considerations are presented. To show the advantages and differences of the proposed inverter with some other recently presented switched-capacitor-based grid-tied inverters a comparison study is considered. Finally, to validate the performance and feasibility of the proposed inverter, various experimental results based on a 620 W experimental prototype are presented.

Hardware Implementation of a Single Phase 11-Level Novel SC-MLI with Reduced Component Count and Boosting Capability

Conversion of DC power into AC power at medium and high level utilize Multilevel-inverter (MLI) because of many advantages of MLI over conventional inverters. The MLI converter topologies have gained a huge attraction towards various applications like photovoltaic and even electric vehicles (EVs). This article represents a new switched capacitor topology (SC-MLI). The proposed SC-MLI contains ten power electronic switches and has a boosting capability with the help of one capacitor. It also uses two input DC sources and has a voltage gain of 1.4. Also, the capacitor is self-balancing and switches have less stress as compared to other configurations. Selective Harmonic Elimination (SHE) technique is employed for the generation of eleven levels. A comparison is also made with the recently developed MLI topologies based on different parameters. Finally, a hardware prototype is developed to check the feasibility of the proposed MLI in the laboratory and satisfactory results have been presented.

A Symmetric Bipolar Quadratic Buck–Boost Converter With Synchronous Triple Switches

A novel non-isolated bipolar DC-DC converter is described in this study. The proposed converter provides negative and positive outputs with the same voltage level and common ground. It exploits three power switches with the synchronous operation, resulting in a simple controller and driver implementation. Compared with the conventional counterpart DC-DC converters, the proposed converter offers buck-boost ability with a wide control range of the switching duty cycle. Additionally, the proposed converter draws a continuous and smooth current from the DC input source, making it an excellent choice for renewable energy sources (RES) and energy storage systems (ESS). Likewise, the proposed quadratic converter can provide a higher voltage boost ability with the same switching duty cycle compared to the existing transformerless bipolar converters. Hence, it offers lower conduction losses and higher efficiency for the same demanded output voltages. Theoretical analysis and experimental results based on a sample prototype are presented to prove the proposed converter's performance in CCM mode.

A MULTIPORT NON-ISOLATED DC-DC CONVERTER FOR HYBRID ENERGY SOURCES BY USING ANN CONTROLLER

The purpose of this paper is to develop a multiport non-isolated DC-DC converter by using an Artificial Neural Network (ANN) based controlling algorithm. In the existing works, various multiport converter and controlling algorithms are developed for improving the power quality and regulating the voltage of hybrid energy storage systems. Still, some of the models are difficult to understand and require an increased component, high power loss, and reduced efficiency. Therefore, the proposed work intends to develop an ANN-based multiport converter, which helps to regulate the voltage according to the desired level properly. Moreover, this converter has many inputs that are connected and operated simultaneously. The hybrid energy sources considered in this work are solar Photovoltaic (PV) cells, wind, and fuel cells. These sources are connected in parallel, and their output is fed to the non-isolated converter as a single input. Since the input sources fluctuate, their output voltage does not maintain a constant value. In order to maintain the constant outputs, an ANN-based controlling algorithm is deployed in this paper, which helps to boost the level of output voltage properly. In addition to that, the Maximum Peak Point Tracking (MPPT) controlling method is utilized to obtain the maximum energy from the input DC source. Then, a rechargeable battery utilizes the backup supply for power generation. During simulation, the whole system is implemented and tested by using the MATLAB/Simulink platform. The obtained results reveal that the ANN-based controlling technique could efficiently reduce the spikes and maintain the constant output at all times.

A transformerless common ground‐based 1‐ϕ single‐stage switched boost inverter for solar photovoltaic applications

AbstractThis paper proposes a transformerless common ground based single phase single‐stage switched boost inverter for solar photovoltaic (PV) applications. In the proposed inverter, the input DC source and output AC load share a common ground. As a result, the high‐frequency common mode voltage across the parasitic capacitance is eliminated, resulting in negligible leakage current ( ) and the associated power loss, and harmonics in the inverter. Moreover, the higher voltage gain of the inverter facilitates the inverter to operate with high modulation index and lower shoot through (ST) duty ratio. Hence, the DC link voltage requirement across the inverter leg is reduced. Consequently, the voltage stress across the switches is minimized. Here, a modified PWM control technique is adopted, where the dual active states of the proposed inverter reduce the inductor current ripple and make it suitable for solar PV applications. The voltage boosting capability of the proposed inverter is extendable with the help of an additional number of intermediate impedance sub‐networks. The detailed steady‐state analysis of the proposed inverter is verified with the help of MATLAB simulation. To verify the simulation results, a 200 W, 120 V, and 50 Hz experimental prototype is developed. The prototype is tested for unity and lagging power factor load conditions with a wide range of input DC voltages, and all the major results are included in the paper. The power and thermal loss analysis is carried out using PLECS software, and the results show that the inverter has a maximum efficiency of 97.48%. From the experimental results, it can be inferred that the proposed inverter has a higher modulation index, lesser inductor current ripple, and zero leakage current as compared to the contemporary inverters.

High Gain Magnetically Coupled Single Switch Quadratic Modified SEPIC DC-DC Converter

This article proposes, analyzes, and tests an improved high voltage gain dc-dc converter based on a single-ended primary-inductor converter (SEPIC). The proposed magnetically coupled quadratic modified SEPIC converter (MCQ-MSC) employs a coupled transformer with an optimized design to obtain a high voltage boost factor by controlling the transformer's turn ratio along with the switching duty cycle. Thanks to the unique structure of the coupled transformer, high voltage gain is obtained at low turns ratio, which is highly desirable for high voltage applications and the compact size of the converter. In addition to the coupled transformer, a voltage-boosting module is utilized to achieve a very high output voltage for a low switching duty cycle. The proposed inverter has a single switch with a wide control range of duty cycle (0<D<1), causing low conducting losses and high efficiency. Furthermore, a clamping circuit is successfully designed to remove the leakage inductance effects of the coupled transformer on the power switch. The proposed MCQ-MSC drains a continuous current from the input dc source, which makes it a suitable choice for renewable energy sources (RES). The hardware prototype of the proposed converter is tested to verify the mathematical expressions and theoretical results.

Simulation Approach for Torque Ripple Minimization of BLDC Motor

This project presents the design and implementation of neural network controller for reducing torque ripples in permanent magnet brushless DC (PMBLDCM) motor drive with trapezoidal back-emf. The performances of the proposed neural network controller are compared with the corresponding fuzzy PI controller and conventional PI controller. Simulation results are used to show the abilities and shortcomings of the proposed speed regulation scheme for brushless dc motor which is considered as a highly nonlinear dynamic complex system. Matlab/Simulink software was used to simulate the proposed model. Buck-boost converter connected in between the input DC source and three phase bridge inverter, used for minimizing the commutation torque ripples in Permanent Magnet Brushless DC Motor is presented in this paper. Torque during the commutation period depends on phase current which is not undergoing commutation, so by controlling it, torque ripple can be minimized. Moreover, a greater DC link voltage is needed during the commutation time period in comparison to the normal conduction period. The Buck-boost converter operates in boost mode in commutation period for stepping up the DC voltage to the inverter. A simple mode switching circuit is employed to amend the output modes of the Buck-boost converter in normal and commutation time intervals. Simulation studies of this topology are carried out in MATLAB/Simulink environment. Index Terms – Permanent Magnet Brushless DC Motor (PMBLDCM), Buck-boost Converter, Commutation Time period,PI Controller.

A performance assessment of nine-stage ternary DC source mli through various PWM topologies

ABSTRACT In modern days, MLIs comprise a lot of concentrations in academia and industry. As they are altering interest in a feasible technology in supporting frequent applications of renewable energy conversion systems and drives, these huge power and medium/higher voltage applications and MLIs are extensively used as one of the sophisticated powers converter topography. The MLIs are divided into two types such as asymmetric and symmetric. MLIs of the asymmetric kind have more amount of output AC voltage stage with fewer DC input source voltage and switching components. In this research paper, asymmetric single-phase cascade full-bridge MLI is developed with carrier-based unipolar PWM techniques. This MLI can generate nine-stage of output AC voltage through eight switches and two input DC sources. It is tested through a variety of multicarrier unipolar PWM control combinations. The Phase Disposition (PD), Alternating Phase Opposition Disposition (APOD), Carrier Overlapping (COP) and Variable Frequency (VF) are all PWM control which included in support of preference of single-phase nine-stage ternary cascade multilevel inverters. With various modulation indices (ma), the harmonic substance of output AC voltage for each approach is observed and tabulated. The proposed design for generating nine-stage output AC voltage is demonstrated using MATLAB-SIMULINK and confirmed using a laboratory-based prototype model. The results show that the unipolar Alternating Phase Opposition Disposition PWM technique that provides a high-quality output voltage with less harmonic distortion. Besides, the performance of Carrier Overlapping PWM techniques is greater since it produces a superior fundamental RMS output AC voltage.

A new transformer‐less common grounded five‐level grid‐tied inverter with leakage current elimination and voltage boosting capability for photovoltaic applications

AbstractDue to serious Concerns such as air pollution, global warming, and fossil fuels shortcoming, renewable energy sources such as photovoltaic applications are dramatically being integrated into the power generation systems all of the world. Here, a new switched‐capacitor‐based transformer‐less grid‐tied inverter has been proposed. By applying the series–parallel switching technique of the utilized switched‐capacitor module, the voltage boosting capability has been obtained. By implementing common ground technique, high overall efficiency and leakage current elimination capability have been obtained. Since the proposed inverter provides a multi‐level output voltage, the total harmonic distortion of the injected grid current is reduced. The introduced control strategy has been implemented to control both active and reactive powers and generate the switches pulses. Therefore, a high quality and adjusted current is injected to the grid. This inverter requires a single renewable energy source as input DC source. Here, the comprehensive description of the proposed inverter and its performance with design considerations have been presented. The proposed structure has been compared with several similar structures and the obtained results have been investigated. To evaluate the performance of the proposed inverter, a 620 W laboratory prototype is assembled and experimental results are analyzed.

THD Minimization and Reliability Analysis of Cascaded Multilevel Inverter

Inverters are DC to AC power converters that are widely used in AC motor drives and distributed energy generation systems. Multi-Level Inverters (MLIs) have emerged as the preferred inverter technology because of their advantages of reduced switching losses and better harmonic profile. This paper deals with the Minimization of Total Harmonic Distortion (MTHD) of Symmetric Cascaded H-bridge Multi-Level Inverter (SCMLI) and Asymmetric Cascaded H-bridge Multi-Level Inverter (ACMLI). A hybrid memetic algorithm composed of heuristic PSO (Particle Swarm Optimization) algorithm and traditional MAS (Mesh Adaptive direct Search) is proposed to optimize the switching angles. In Photo Voltaic (PV) system, the input DC voltage generally varies from its nominal value due to the change in temperature and irradiance. Thus, the sensitivity analysis of THD and harmonics is also carried out considering the variations with non-integer magnitudes of input DC sources. The experimental prototype of SCMLI and ACMLI topology is developed and validated with simulation results. The reliability and Mean Time to Failure (MTTF) of SCMLI and ACMLI are investigated based on power losses of the MOSFET and thermal parameters.

A Reduced Switch Count Multilevel Inverter for PV Standalone System using Modified JAYA Algorithm

ABSTRACT This paper introduces a hybrid multilevel inverter (MLI) with reduced switch count, which can generate higher output voltage level with minimum number of DC input sources. The operation of this proposed MLI is carried out with unequal DC sources to achieve the desired output voltage level. The reduced MLI output voltage is set to minimal total harmonic distortion (THD) with the help of modified JAYA (MJAYA) algorithm. A JAYA algorithm with improved steps by adopting an accelerating parameter has been proposed in this research work to obtain a faster convergence of the objective function. The MJAYA algorithm has provided the suitable switching angles for the proposed three-phase 15-level MLI and reduced the output voltage THD to 2.23%, which satisfies the standard set by IEEE-519. To prove the efficiency of this proposed modified algorithm, the comparative analysis is carried out through MATLAB program and Simulink tool using common JAYA and modified particle swarm optimisation algorithms. The performance and productivity of the proposed MLI have been investigated through simulation and experimental setups.

A New Topology of Single-Phase Common Ground Buck-Boost Inverter With Component Voltage Rating Reduction

The combination of conventional front-end DC-DC converter and H-bridge inverter has been proposed with common-ground (CG) characteristic and voltage booting capability. However, it has drawback of low modulation index utilization which causes high component voltage rating and small conversion efficiency. In this paper, a new topology of a single-phase common-ground buck-boost inverter (1P-CG-BBI) is presented to overcome existing drawbacks of conventional CG inverters. The proposed 1P-CG-BBI uses one more active-switch and one more diode than traditional CG inverter. Note that the proposed inverter still shares the same ground for DC input source and AC output voltage, which completely eliminates the leakage current. A hybrid pulse width modulation (PWM) technique is introduced to control the buck-boost stage. Accordingly, the buck-boost stage of the 1P-CG-BBI operates similar to a conventional DC-DC boost converter in the positive half cycle. In the negative half cycle, this stage behaves as a traditional inverting DC-DC buck-boost converter. Accordingly, the DC-DC operation and DC-AC operation can be controlled, independently. Consequently, the modulation index can be significantly improved compared to previous CG inverters. High modulation index tends to reduce component voltage rating and increase system efficiency. A comparison study has been discussed to highlight these advantages. Simulation results conducted using PSIM software are considered to verify the operation of the proposed inverter. A laboratory prototype is also developed to further demonstrated the accuracy of theory. Accordingly, the proposed inverter obtains 93.12% and 91.83% efficiency at 550-W for buck and boost operating, respectively.

Modelling and Analysis of Non-ideal Two stage Lift Luo Converter with Positive Output

High power applications such as motor drive control requires a higher voltage level of the DC-DC power converter fed from low-level DC input sources. For increasing the output voltage, a gain of the converter is increased using the pump circuit consisting of inductors and capacitors connected in different forms. The effect of adding the energy storage elements includes the parasitic resistances in the converter and affects the performance. This research paper is intended to model and investigate the effects of non-idealities in two stages cascaded lift circuit type Luo converter with positive output voltage. To analyze the non-ideal effects, state-space averaging (SSA) technique is used to model the converter. The converter is modeled in the presence of equivalent series resistance (ESR) of inductances and capacitances to study the effect of parasitic resistances on the converter performances. The transient and frequency response of the converter is plotted using the MATLAB simulation and observed that the ringing in the transient response is damped and oscillation at corner frequency is mitigated. The effect of ESR reduces the voltage gain and improves the stability of the system by increasing the gain and phase margin. Step response and bode plot of the converter is plotted at ideal and non- ideal condition.

A Common-Ground-Type Five-Level Inverter with Dynamic Voltage Boost

Today, transformerless inverters (TIs) are widely applicable in different solar photovoltaic (PV) grid-connected applications owing to their promising features, such as higher efficiency and power density. However, high-frequency common-mode voltage (CMV) in these topologies can result in high leakage current, electromagnetic interference, and lack of safety, reducing the whole system’s reliability. To resolve the problems associated with TIs, this paper proposes a novel hybrid switched capacitor (SC)-based common-ground (CG) transformerless inverter (TI) topology, which can be applied in grid-connected photovoltaic (PV) applications. The boost inductor is integrated to achieve continuous input current and dynamic voltage gain. In addition, the proposed circuit comprises nine switches and two SCs with a single input DC source. It can generate five-level AC voltage with voltage boosting within a single-stage DC–AC power conversion. The working principles of the proposed topology, circuit description, and control technique are presented. Furthermore, the proposed inverter is comprehensively compared with other five-level TIs to show its superiority. Finally, a laboratory prototype is developed and tested to validate the practical viability of the proposed configuration.