Reduced Voltage Stress Research Articles

Sustainable power conversion topology based STATCOM for reactive power compensation

The stability of AC voltage is one of the vital drawbacks affecting the power transfer capability. FACTS devices open a new control technology for mitigating this problem to a great extent. But the size, DC link utilization, and stability of the controlling device is still a major concern. The main thrust is to improve the quality of reactive current injected for voltage enhancement in the power system. This paper proposes a new inverter based STATCOM with fewer components and high DC link utilization. This will reduce voltage stresses across the devices. The required DC link voltage is being curtailed by 1.57 times. When compared to multilevel level inverters, less number of switches and one high-frequency switching is required per phase. The simultaneous switching of devices in the same leg eliminates the shoot-through problem. The proposed method improves the quality of injected current for reactive power compensation and load voltage has attained THD (total harmonic distortion) 2%. MATLAB- Simulink platform is used for simulation and verified with experimental results.

A High Voltage Gain ZVT Quasi-Z-Source Converter With Reduced Voltage Stress

In this article, a new high voltage gain quasi-Z-source (QZS) dc–dc converter suitable for renewable energy applications is presented. The proposed converter utilizes a zero voltage transition auxiliary circuit with coupled inductors to provide soft-switching conditions for all switches for a wide range of output power. In addition, a switched capacitor circuit is employed to obtain a higher voltage gain and lower voltage stress. The main advantages of the proposed converter include high voltage gain, high efficiency, reduced switch and diode voltage stress, continuous input current, and common ground between the output and input, which are important features for photovoltaic applications. In this circuit, the reverse recovery problem of diodes is alleviated. Operating principles and design considerations of the proposed converter are analyzed. Moreover, to prove the validity of the theoretical analysis, a 200-W prototype of the proposed converter is implemented and the experimental results are shown.

Nonisolated Boost Converter with New Active Snubber Structure and Energy Recovery Capability

The boost converters have become one of the most important part of renewable energy plants. The two parameters of boost converters, high voltage gain and high efficiency, have received more attention. In this paper, a boost converter with high voltage gain and high efficiency was used. The proposed topology is a boost converter with high transmission power and reduced voltage stress on the converter components, especially voltage stress on the main switch of the converter. This boost converter has a high efficiency using a new loss reduction technique called active snubber circuit with energy recovery. The proposed nonisolated topology converter was designed with a power of about 500[Formula: see text]W, an input voltage of 48[Formula: see text]V and an output voltage of 380[Formula: see text]V and efficiency of more than 97%. The simulation results of the proposed converter showed different modes of the boost converter. A laboratory model was constructed and the claims of the proposed boost converter were proved.

Ultra-High Step-Up Gain Interleaved Coupled Inductor DC–DC Converter with Reduced Voltage Stress and Eliminated Right Half Plane Zero

Ultra-High Step-Up Gain Interleaved Coupled Inductor DC–DC Converter with Reduced Voltage Stress and Eliminated Right Half Plane Zero

Modular SEPIC-Based Isolated dc–dc Converter with Reduced Voltage Stresses across the Semiconductors

This paper presents the theoretical analysis, experimental results and generalized structure for N modules of an isolated dc–dc SEPIC converter. The structure comes from the integration of N conventional SEPIC converters based on the input-series and output-parallel connection. The main advantages provided by the proposed structure are reduced voltage stress across the semiconductors and division of the current stress in the output diodes. The proposed converter is presented in a generalized approach, varying the voltage stress across the semiconductors according to the number of modules used. As the converter uses more than one switch, the commands can be either equal or phase-shifted by 360∘/N degrees. When operating with phase-shift modulation, a multilevel converter is obtained, which brings another advantage of the structure, since there is a reduction in the volume of the input inductors (Li1 and Li2) and the output capacitor (Co). In this paper, the steady-state analysis, a dynamic model, system control and experimental results are presented for phase-shift modulation and discontinuous conduction mode (DCM). The performance of the proposed converter was verified in a prototype with four modules and the following specifications: 500 W output power, 800 V input voltage, 120 V output voltage and 50 kHz switching frequency. The converter achieved 94.42% efficiency at rated power.

A three‐level isolated dc‐dc SEPIC converter with parallel‐connected output

AbstractThis paper presents a comprehensive theoretical analysis and experimental results for three‐level isolated dc‐dc converter based on the single‐ended primary‐inductance converter (SEPIC) topology. The main advantage of this structure is the reduction of voltage stress on semiconductors comparing it to the conventional SEPIC converter. Voltage stress is the major challenge associated with the conventional SEPIC structure, and contributions in this area can extend the range of applications for the family of SEPIC converters. The analyzed structure contains two switches, and their commands can be either equal or phase‐shifted by 180°. This provides four different modes of operation in discontinuous conduction mode (DCM), which have different operating stages, waveforms, and design equations. In this paper, the topology with parallel‐connected output and the static and dynamic theoretical analysis in DCM, for the four command signal profiles, are presented. The advantages and disadvantages, control strategy, experimental results, and a comparative analysis with the conventional SEPIC converter are discussed. The dc‐dc SEPIC converter was verified by experimental results from a proof‐of‐concept prototype with 500 W rated power, 400 V input voltage, 120 V output voltage, and 50 kHz switching frequency. The converter achieved 94.72% efficiency at rated power.

A new interleaved high step‐up soft switching converter with simple auxiliary circuit and reduced voltage stress

This paper proposes a soft-switching high step-up DC/DC interleaved boost converter. The converter uses an interleaved structure to decrease input current ripple. The coupled inductor technique achieves high voltage gain without needing the extremely increased duty cycle. The applied auxiliary circuit provides zero-voltage-switching (ZVS) condition for both main switches with a minimum number of elements. In addition, all the diodes turn off with zero-current-switching (ZCS), alleviating the reverse recovery problem. Moreover, all power switches and diodes have low voltage stress. The voltage stress of the auxiliary switch is low, resulting in low Coss losses of the auxiliary switch. The other properties of the proposed converters are continuous-low-ripple input current, no need for the floating gate drive, and small size. The theoretical analysis is validated by a 250-W prototype with 40-V input to 400-V output voltage with a 100-kHz.switching frequency.

Implementation of Two-Stage Multilevel Inverter System Using PIC Controller

In this study, the Cascaded H-Bridge Multilevel Inverter (CMLI) is described for use with infrared dryer loads. Because of the low harmonic distortion content and reduced voltage stress in the switching devices, CMLI is one of particular interest. The CMLI topology and the Selective Harmonic Elimination Pulsed Width Modulation (SHEPWM) technology were studied and evaluated. To evaluate the inverter, SHEPWM modulation was studied and applied. The system also includes a DC-DC converter. The converter was designed to be used in infrared drying system powered by direct current (DC) power where an increased output voltage is required. This study also presented an evaluation of performance using infrared load of the CMLI based on power used at 100 W. As a result, a comparison of input power was made, and an assessment into the converter's power quality in terms of harmonic content and overall efficiency was conducted. The implementation of the system by hardware had been able to reduce the harmonic to 15.5%.

A high step‐up DC‐DC converter based on coupled inductor and diode‐capacitor with improved voltage gain and efficiency, and reduced voltage stress for photovoltaic systems

AbstractThis paper proposes a nonisolated high step‐up dc‐dc converter, which optimally integrates coupled inductor, and diode‐capacitor and provides superior features such as high gain, high efficiency, and low voltage stresses on power switches. Moreover, the common ground between the input and output of the proposed converter makes it appropriate for photovoltaic systems. It consists of two power switches, one inductor, one coupled inductor (CI), four diodes, and four capacitors. The power switches are exposed to low voltage stresses and are selected from low voltage ratings and low on‐resistance semiconductors. The topology, operating principle, complete steady‐state and ac small‐signal models, loss model, and design criterion are presented and described in detail. Also, the proposed topology is compared with other previous topologies. In order to evaluate the performance of the proposed converter, a 400 V/400 W experimental prototype has been designed and built. Experimental results validate the theory and show the converter produces high gain (14.25 times in the full‐load condition tested) and operates with high efficiency (94.9% in the full‐load condition).

A High Step-Up Three-Port DC–DC Converter With Reduced Voltage Stress for Hybrid Energy Systems

In this article, a novel three-port dc–dc converter for hybridized energy applications is proposed. The suggested converter's circuit structure applies one coupled inductor (CI) and two CI-based voltage multipliers to increase the voltage gain. The input energy source can supply power to the output load and either charge or discharge the battery. The coupled inductor's leakage inductance is utilized to facilitate zero current switching of all power switches. In addition, by controlling the multiplier diodes' current falling rate, it reduces their reverse recovery losses. Furthermore, all semiconductors' voltage stresses are significantly decreased. The steady-state analyses and considerations for the proposed structure's design are discussed and presented in the various operation states. Also, a closed-loop multi-input-multi-output control method is presented and used to ensure the controllability of the system. Moreover, power management algorithm is defined and applied in the control strategy. Finally, the analysis is supported by experimental results from a 535 W laboratory prototype.

Boost DC-DC Converter with Switched-Capacitor and Four-State Switching Cell

The integration of switched-capacitor voltage multiplier cells in basic converter topologies has been studied to provide voltage gain and voltage stress reduction. However, SC cells do not provide current sharing and additionally they induce high current spikes in the devices, which are limitations of these structures to operate in high power levels. The main contribution of this paper is to overcome this drawback proposing the use of a multistate switching-cell for current sharing in SC-based boost converters, which reduces the current stress in the power devices and increases the power levels of this family of converters. The proposed concept can be generalized for m number of SC cells and n number of switching cells to increase the voltage gain and current levels. Furthermore, it can be applied to other basic structures. The theoretical analysis of the proposed structure was evaluated experimentally in a 3 kW boost-type dc-dc converter, achieving 200 V to 1200 V voltage gain, and reaching 98.4% of maximum efficiency.

A dual‐output single‐input non‐isolated DC‐DC converter with reduced semiconductors stress

AbstractThis work proposes a novel topology of two‐output high voltage rate DC‐DC converter based on coupled inductor and voltage multiplier cells (VMCs) techniques for renewable energy usages like photovoltaic (PV) systems. The proposed structure has two independent output ports with two voltage gains (M1 and M2). Low voltage stress across the power switch and diodes, common ground between input and output ports, high efficiency, and reduced number of elements are the advantages of the suggested converter. The used diodes are switched at zero current switching (ZCS) and zero voltage switching (ZVS) conditions, which reduce the losses of diodes and subsequently increase the power efficiency. Due to the usage of the coupled inductor, there is no need to a high value of the power switch's duty cycle. Therefore, a low conduction loss and higher efficiency can be obtained. On the other hand, because of the reduced voltage stresses, low rated semiconductors can be used for operation of the presented converter, which decrease the cost and the volume. To demonstrate the performance and effectiveness of the proposed topology, operation principles, steady‐state and efficiency analysis, and also the comparison assessment are provided. Finally, a 200 W experimental development with 50 kHz operation frequency, 20 V input voltage, and 200 and 100 V loads voltages has been implemented in the lab to prove the mathematical surveys.

Enhanced Performance of On-board EV Battery Charger with Universal Power Supply

This paper is intended to provide enhanced features of onboard EV battery chargers in terms of improved power quality feature, reduced voltage stress, reduced filter size, high efficiency and fast dynamic response for universal input voltage range (85–265 V). The proposed configuration comprises of three-level quadratic converter suitable to provide high voltage gain. The detailed operation, analysis and control scheme of the proposed converter rated for 3.2 kW, 400 V are studied under simulation and hardware in a loop environment. The on-board charger performances are assessed by charging a 40 Ah lithium ion EV battery under different charging modes. The state of charge of battery decides converter operating mode i.e. constant current and constant voltage mode to charge the battery. Enhancement in the onboard charger is observed in both operating modes tested for wide variation in supply voltages. The results reveal that the operation of converter depicts unity power factor operation, improvement in supply current harmonics and controlling output voltage/current. Under both operating modes, the proposed charger draws sinusoidal supply current from ac mains and its THD is reduced to specified limit prescribed by IEC-61000-3-2. Furthermore, the charger performance is also investigated for EV battery charging operation at wide input voltage variations and found satisfactory.

A high gain soft switched DC–DC converter for renewable applications

ABSTRACT This article presents a novel high gain soft-switching DC–DC converter with low component count and low voltage stress across switching devices. The proposed converter employs coupled inductor and voltage multiplier techniques to achieve high gain at low duty and low turn ratios. An active clamp circuit is also used to reduce voltage stress across the switch. As a result, lower voltage rating switches having lower on-state resistance (Rds-on ) are used, lowering system cost. It also helps to achieve zero voltage switching (ZVS) turn-on across both MOSFETs, reducing switching losses and improving efficiency. The leakage energy of the coupled inductor is recycled to improve the voltage gain, and the quasi resonance formed by the leakage inductance and switched capacitors helps to achieve zero current switching (ZCS) across diodes. This also helps in controlling the falling rate of output diode current, helping to mitigate the reverse recovery problem. The steady-state analysis has been carried out. A 500W prototype of the proposed converter is built up and tested to validate the working of the converter.

Two-Stage Step-up Converter with Different Voltage TransformationRatios depending on the Duty Cycle

A two-stage converter with high output voltage ratio and reduced current stress of the inductors and partly reduced voltage stress is discussed. The function is explained with the help of voltage and current diagrams. The voltage transformation ratio changes between a quadratic step-up for duty cycles lower 0.5 and a double Boost converter for duty cycles higher than 0.5. Dimensioning hints, the control law for feed-forward controls, the transient when the supply is turned on is discussed and some simulations are given. A comparison to other two-stage converters is also treated.

Enhanced quadratic boost converter based on voltage lift technique for fuel cell powered electric vehicle

The proton exchange membrane fuel cells (PEMFC) are inherently low voltage and high current sources. Since high voltage is required for motor drives present in fuel cell-powered electric vehicles (FCEV), power converters are required for the integration of PEMFC into the motor drive system. To address this need, the study presented below describes the development and analysis of the proposed high gain step-up converter as a power electronic interface in FCEV. The proposed converter configuration utilizes the voltage lift technique in conjunction with the quadratic boost converter (QBC). The voltage lift technique uses a pair of diodes and capacitors to enhance the voltage gain and to reduce voltage stress across the power switch. A reduction in the voltage stress allows utilizing a low on-state resistance for the switch resulting in improved efficiency of the converter. In addition, the proposed converter draws a continuous or non-pulsating input current from the fuel cell stack which helps to improve its life cycle as well. The performance of the proposed converter is superior to alike converters in terms of voltage gain, voltage stress and the number of components utilized. The operating principles, steady-state analysis in continuous conduction mode (CCM) and key design parameters are described below to prove the superiority of the proposed converter. Finally, a hardware prototype of 200 W is fabricated and tested to affirm the validity of the theoretical analysis. The proposed converter exhibits an efficiency of 94.02%.

Single-Phase Boost Switched-Capacitor-Based Multilevel Inverter Topology With Reduced Switching Devices

A multilevel inverter (MLI) with a step-up feature has become significant for connecting a low-voltage PV system with a utility grid. An MLI has been presented in this article with a lower component count. The described structure has achieved nine distinguish voltage levels using 12 switches and a switched capacitor unit having twice voltage boost. A self-balancing of the floating capacitor voltage without any auxiliary circuits and precharging has been obtained. The new topology includes fewer switches, reduced voltage stress, and an inherent reversing polarity without the back-end H-bridge, which has been the additional feature of the proposed circuitry. The topology proposed has been controlled with the nearest level control pulsewidth control technique (NLC-PWM). A comprehensive comparative analysis with several similar topologies has been presented in this article to show the merits of the recommended topology. A number of simulation results using PLECS software have been discussed along with experimental results that have been obtained from a laboratory prototype. The validation of the proposed topology has been carried out using different steady-steady and transient operating conditions.

High-Gain Compact Interleaved Boost Converter With Reduced Voltage Stress for PV Application

This article proposes an interleaved, highly efficient, high-gain modified boost converter. High-gain and transformerless converter operation makes the converter suitable for integrating photovoltaic (PV) power to standalone dc microgrid. A coupled inductor is used with two diodes and one switch per phase with a common clamping capacitor to modify the conventional boost converter. The common clamping capacitor and the coupled inductor reduce the converter’s component count and size; thus, high efficiency is achieved at a low cost. The proposed converter achieves a high step-up gain and low voltage stress on switches. Interleaved converters are deemed ideal for PV power extraction as they exhibit low input current ripple. A 900-W prototype of a two-phase interleaved modified boost converter is designed and developed to verify the working principle of the converter and performance testing.

Design a Simulation of Multilevel Inverter for Reduction of Harmonics for Grid Connected PV System

Abstract: The existing topologies, Multilevelinverters acts as a promising solution for medium voltage, high power applications due to their modularity and reduced voltage stress across the power switches. They are becoming popular due to reduced voltage stress of the power switches and low THD. Among the different multilevel configurations, H bridge multi-level inverter (HBMLI) is found to beattractive for grid connected PV applications. H Bridge Multilevel Inverters (HB-MLI) are being considered as the best choice for grid connected Photovoltaic (PV) systems since they require several sources on the DC side. By means of high-quality output with less harmonic distortion is obtained compared to a two-level inverter. Different levels of output viz. three level is examined and conclusions are drawn mainly based on the number of switches andTotal Harmonic Distortion (THD). The main advantages of the multilevel inverter are that the regulation of the DC buses is simple. More number of levels results in reduced THD and nearly sinusoidal output. Simulation is performed using Matlab/Simulink.

Design of quasi‐Z source converter for vehicle to vehicle to battery charging application

AbstractThe Quasi‐Z‐source converter (QZSC) is the favorite dc‐dc converter that can be applied to applications like EV battery charging, microgrid, distributed generator, etc. QZSC is the modified version of the Z‐source converter (ZSC) which has the additional qualities of uninterrupted input current and a broad range of input voltage over ZSC. In this article, QZSC is especially developed for the dc‐dc like vehicle‐to‐vehicle (V2V) battery charging application. Due to the availability of shoot‐through conditions, QZSC overcomes the burden of the additional dc‐dc booster, unlike a two‐stage converter. This additional benefit of the shoot‐through condition makes QZSC more worthy than a conventional converter. The elaborated design analysis of the QZSC is presented in this article which found reduced voltage stress across one of the capacitors, unlike the traditionalistic impedance source converter. The hardware prototype of QZSC is developed and experimental results are obtained. The experimental results are verified by using simulation and theoretical results. Experimental results suggest that the QZSC converter concept could be most suitable for the V2V battery charging applications. Simulation results are obtained for QZSC by using a matrix laboratory.