Voltage Balancing Research Articles

A Novel High-Gain Switched-Capacitor Multilevel Inverter with Reduced Components for Grid Integration

This paper introduces a novel Multi-Level Inverter (MLI) design which utilizes a single input and leverages capacitor voltages source to generate a four-fold increase in output voltage as the main problem that stays with the inverters is their low boost ability and efficiency while maintaining power quality at the same time. One capacitor is charged to match the input voltage magnitude, while the other two capacitors store twice this magnitude. Through a series-parallel combination with switching operations, all capacitors are effectively charged and discharged within each cycle, ensuring natural voltage balance. A comprehensive comparative analysis is conducted to highlight the advantages of this innovative approach, particularly in terms of component reduction and mitigation of voltage stress. Detailed assessment of power losses within the proposed circuit is undertaken, simulation studies are first carried out while extensive experimentation verifies its operational efficiency under diverse conditions such as varying modulation indices, loads, and supply-side fluctuations with an impressive maximum efficiency of 96.9 % at a 200 W power rating, our research contributes to advancing compact power converters, addressing crucial challenges in modern power electronics applications, and paving the way for enhanced performance and reliability in such systems.

A single DC source, seven-level switched capacitor tripple boost inverter with fewer switches for renewable energy applications

This article presents a new SSTB-MLI with 3 times voltage boosting capability for medium voltage applications with optimal efficiency. Single DC source MLI topologies are more appropriate for many applications, including grid applications and renewable energy (RE) conversion systems than multiple DC source MLI topologies. The ability of switched-capacitor multi-level inverters (SCMLIs) to raise voltage has made them more and more popular in recent years. LS-PWM technique is used for the switching scheme. Two capacitors are employed in SSTB topology to operate alternatively in charging and discharging states at the carrier frequency of this LS-PWM algorithm for making the levels of output voltage. Comparing this innovative topology to those documented in the literature. It can also minimise the number of switches and capacitors needed, their voltage stresses, and switching loss. Since the suggested topology includes built-in capacitor voltage balancing, no additional voltage balancing circuit is required. Applications requiring industrial drives as well as grid-connected and R, RL loads can employ the suggested architecture. Based on less TSV (total standing voltage), MSV (Maximum standing voltage), the number of components used, optimum efficiency 98.43%, and other factors, a comparative analysis is done between the existing topology and the proposed topology. Experimental data and thorough simulation are used to verify the suggested switched capacitor multilevel topology.

Self-Voltage Balanced Switched-Capacitor Seven-Level Inverter for Asymmetrical Solar PV Source Applications

In this paper, a novel structure of self-voltage balanced switched-capacitor-based seven-level inverter (SVB-SCSLI) is proposed for asymmetrical input energy source applications. SVB-SCSLI develops a seven-level staircase waveform with a minimum number of semiconductor devices compared to existing multilevel inverters (MLIs). The proposed converter is more suitable for the solar PV system where unequal DC voltage sources are available. The SVB-SCSLI also resolves the main difficulty of connecting many inverters in parallel to achieve staircase voltage. Besides, it attains voltage balancing capability at DC-link by holding constant capacitor voltage at every cycle. The detailed loss and steady-state analysis of the SVB-SCSLI are examined. Furthermore, the proposed converter’s efficiency improves with better power quality than other topologies reported in the literature. Finally, a prototype is fabricated, and experimental results are presented to validate the feasibility of SVB-SCSLI.

Fast and Accurate Neutral-Point Voltage Control Under Balanced and Unbalanced Neutral-Point Voltage for Coupled Ten-Switch Three-Phase Three-Level Inverter

Fast and Accurate Neutral-Point Voltage Control Under Balanced and Unbalanced Neutral-Point Voltage for Coupled Ten-Switch Three-Phase Three-Level Inverter

Fuzzy Logic Control of Two-Stage Grid- Connected Photovoltaic System

In this paper, a two-stage grid-connected photovoltaic system is presented. The optimal performance of solar panels at varying temperatures and irradiance levels is achieved by the application of a fuzzy logic-based maximum power point tracking method. Space vector modulation is used to control the inverter; to achieve capacitor voltage balance, redundant switching states of a three level inverter are used. The grid side control regulates the power and the current injected to the grid, the conventional PI controllers are replaced by fuzzy PI. Simulations have been made using Simulink environment on MATLAB to validatethe control of the proposed system.

Transformer-Less Seven-Level Inverter with Triple Boosting Capability and Common Ground

This paper proposes a single-phase, transformer-less, seven-level inverter that utilizes eight switches, three capacitors, and two diodes to produce seven voltage levels with triple boosting ability. The availability of the common-ground point eliminates the leakage current in PV applications. The proposed Transformer-Less Triple-Boosting Seven-Level Inverter (TLTB7LI) has the ability to feed different types of loads from non-unity to unity power factors. The voltage balancing of capacitors takes place naturally without the need for auxiliary circuits and complicated control strategies. This paper investigates the appropriateness of the proposed TLTB7LI for grid-connected application. The Peak Current Controller (PCC) is employed to generate the switching pulses and regulate the active/reactive power transfer between the converter and the output, which guarantees the high quality of injected current to the output. Moreover, the operational principles, its control technique, as well as the design procedure of the key components of the proposed inverter have been presented. The superiority of the proposed inverter over existing counterparts has been verified through comparative analysis. The simulation and experimental analysis validated the proper operation of the proposed TLTB7LI.

A 17-level octuple boost switched-capacitor inverter with lower voltage stress on devices

This paper presents a new structure for switched-capacitor multilevel inverter with octuple voltage gain capability. The proposed inverter utilizes three capacitors, 13 semiconductor switches, three diodes, and an input voltage source to achieve a 17-level output voltage. The switched capacitors naturally achieve voltage balancing without the need for sensors or additional circuits, indicating the ease of control of the proposed structure. To control the inrush current of the switched capacitors, a charge limiting inductor has been utilized in the charging path of the capacitors. This not only reduces the inrush current of the capacitors and the input source current but also enables faster capacitor charging and extends their lifetime. The switches used in the proposed structure can withstand a maximum of 4 times the input voltage value or the half of the maximum output voltage, which is a significant advantage for the proposed structure. A detailed comparison with similar structures is provided to examine the advantages and disadvantages of the suggested inverter. The procedure of self-voltage balancing of the capacitors and the functional modes of the proposed topology has been explained in detail. The proposed structure is suitable for applications such as renewable energy sources transfer to load or grid. The performance of the proposed topology under different conditions is confirmed through simulation in the Matlab\\Simulink software and the implementation of the laboratory sample.

Performance analysis of amd ryzen 5 4600h mobile processor undervolting using AMD APU tuning utility on cinebench R23

In an effort to optimize laptop performance for gaming and high-demand applications without costly hardware upgrades, this research investigates the impact of CPU undervoltage using the AMD Ryzen Mobile 4600H processor. Undervolting, the process of reducing the CPU's voltage supply, is proposed as a strategy to enhance performance by lowering operational temperatures, potentially allowing for more efficient processing. This study uses the AMD APU Tuning Utility to adjust voltage settings and assesses performance changes using a series of benchmarks. Initial findings indicate that undervoltage can indeed have beneficial effects. The most significant data point from the research is the comparison of Cinebench R23 scores before and after applying undervolting settings. From a baseline score of 6835 points, system performance increased to 7880 points in the optimal undervolting scenario, an improvement of 1045 points. This shows a noticeable enhancement in processing efficiency. However, the study also reveals some complexities in undervolting, such as an initial drop in performance in the first configuration before gains are realized in subsequent adjustments. Efficiency values varied across different settings, starting with a decrease (-0.41) and culminating in a substantial gain (+1.54) by the fourth configuration. These results suggest that while undervolting can improve performance, the outcomes depend significantly on finding the right voltage balance, highlighting the nuanced nature of CPU voltage manipulation for performance optimization.

Correction: Kim et al. Zero-Sequence Voltage Injection Method for DC Capacitor Voltage Balancing of Wye-Connected CHB Converter under Unbalanced Grid and Load Conditions. Energies 2021, 14, 1019

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Enactment of HBMMC five-level inverter based D-STATCOM using robust controllers

This paper provides the results of a concerted investigation into developing a robust voltage controller for the modular multilevel converter (MMC) used in the D-STATCOM. The simplicity of the half bridge (HB) sub-module, along with the fact that it has minimal conduction losses, led to its adoption in the MMC. For the purpose of controlling the HB MMC switches, an enhanced modulation strategy based on the phase disposition (PD) scheme has been implemented. In the presence of nonlinear load conditions, the converters are experiencing difficulties with the DC voltage balancing. The sliding mode controller (SMC) is utilized so that the DC voltage can be maintained in a balanced state. Performance characteristics including active power, reactive power, dc voltage control and THD are shown and compared. For the purpose of simulating the indicated methodology, MATLAB/Simulink is the tool of choice.

A Distributed Turn-Off Delay Compensator Scheme for Voltage Balancing of Series-Connected IGBTs

A Distributed Turn-Off Delay Compensator Scheme for Voltage Balancing of Series-Connected IGBTs

Coordinated Capacitor Voltage Balancing Method for Cascaded H-Bridge Inverter with Supercapacitor and DC-DC Stage

Coordinated Capacitor Voltage Balancing Method for Cascaded H-Bridge Inverter with Supercapacitor and DC-DC Stage

A Novel Driving Strategy for the APMSM Based on Half-Bridge Topology With Midpoint Voltage Balancing

A Novel Driving Strategy for the APMSM Based on Half-Bridge Topology With Midpoint Voltage Balancing

An Active Virtual Space Vector Modulation Scheme for Three‐Level Neutral‐Point‐Clamped Converters

The performance of neutral‐point‐clamped (NPC) converters is subject to the regulation of neutral point balance. In the literature, researchers have addressed two main modulation methods: the active space vector PWM (SVPWM) technique and the virtual SVPWM (VSVPWM) method. However, those two approaches respectively suffer from reduced DC‐link voltage utilization and poor active regulation capability. To address this, an improved VSVPWM modulation scheme with actively strong voltage regulation capability is proposed in this paper. The fast and precise control of capacitor voltages is achieved by optimizing the synthesis scheme of the virtual vectors. When there is a voltage imbalance, the proposed technique can quickly restore and maintain the capacitor voltage balance till the full DC‐link voltage utilization without affecting the converter output quality. The experimental validation results on the NPC converter have demonstrated the benefits of the proposed active VSVPWM method. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

FRT capability improvement of a wind power system using support vector regression and deep neural network models

ABSTRACT The increasing energy demand and environmental conditions have led many countries to favor renewable energy,such as wind and solar,over conventional power plants. As per the Central Electricity Authority (CEA), India’s wind power capacity has grown substantially, reaching 45,154 MW in 2023, from 22,465 MW in 2013. However, integrating wind generators to an existing power system network can reduce transient stability during faults. To prevent wind turbine disconnection during faults, Indian grid code authorities mandate Fault Ride Through (FRT) or Low Voltage Ride Through (LVRT) capability for wind turbines. This paper proposes Dynamic Voltage Restorer (DVR) for enhancing the FRT capability of a constant speed wind turbine. Analysis and simulation are done on a fixed speed wind turbine employing Squirrel Cage Induction Generator (SCIG) under balanced and unbalanced voltage sags. Performance of DVR with two Artificial Intelligence-based controllers, Support Vector Machines(SVM) Regression Model Based Supervised Machine Learning algorithm, and Deep Neural Network (DNN) controller, is analysed and compared. The SVM Regression algorithm, achieves 100% voltage sag compensation under unbalanced voltage sags, reduces torque pulsations to 25% and maintains rotor speed at rated values, enabling the turbine to remain connected to the grid. Additionally it reduces Total Harmonic Distortion to 2%.

Modulated model predictive current control technique for triple‐boost seven‐level switched capacitor‐based inverter topology

SummaryTraditionally, the finite control set‐based model predictive current control technique (MPC2T) inherently wrenches from the variable switching frequency of operation. To obtain the fixed switching frequency of operation, different types of predictive control approaches have been reported in the literature. However, these are complex while going to single‐phase higher‐level inverter topologies and are not to be generalized in a simple manner. In this paper, a new generalized modulated MPC2T has been proposed for single‐phase switched capacitor‐based multilevel inverter (SC‐MLI) topologies. In this technique, the optimum inverter output voltage (O‐IOV) has been generated by nullifying the derivative of the cost function. The normalized O‐IOV is fed to a new single modulating floor function (F2) single carrier‐based pulse width modulation technique. Compared to all routine PWM approaches, this specific F2‐based modulation stage is extremely straightforward even for higher‐level inverter topologies. The sensorless voltage balancing of switched capacitor topologies completely eradicates the need for weighting factors in predictive algorithms. To verify the robustness and performance of the perspicuous proposed technique, the conventional triple boost SC‐MLI topology has been considered and elucidated with the different steady and dynamic operation of results.

Voltage balancing for active power filter using dual-frequency multicarrier modulation with balanced H-bridge control

In this paper, a switching control method integrated with voltage balancing feature is presented to manage operation of single-phase 5-level cascaded H-bridge (CHB) inverter as parallel-connected active power filter (PAPF), and at the same time maintain its voltage balance. CHB inverters are always preferred for PAPF due to their dominating features of modularity, flexibility and least components count. However, inherent voltage unbalance issues of CHB inverter which is due particularly to unequal switching operation across its individual H-bridge module have always been the most troublesome when handling CHB inverter. For consistent voltage balance across each H-bridge module, proportional-integral (PI) controller for voltage balancing control and multicarrier sinusoidal pulse-width modulation (MCSPWM) for switching control have commonly been integrated together. However, these conventional approaches do not directly address the issue of unequal switching. Hence, in this work, effort is performed to allow each individual H-bridge module to operate with balance switching pattern, by evenly distributing the PWM switching signal to them. Design concept of the proposed method is modeled in MATLAB-Simulink platform. To critically assess its effectiveness, comparative analysis involving two types of highly nonlinear rectifier loads and distorted grid is performed. The presented simulation findings confirmed effectiveness of the proposed method in maintaining voltage balance of the 5-level CHB inverter when mitigating harmonics under adverse grid.

A new triple voltage gain seven level switched capacitor-based inverter with minimum voltage stress

Abstract This paper presents, a new seven level triple voltage gain inverter topology is proposed based on switched capacitor technique. The proposed inverter topology has minimum voltage stresses on the switches and balanced capacitor voltages. This paper briefs the operation of proposed topology, voltage stress analysis, capacitor sizing and generation gate signals for the switches. In addition, proposed topology is modeled in industrial based software PLECS with practical switches to study thermal behavior and efficiency analysis. Further, the proposed inverter topology is compared with competitive topologies in the recent literature. The proposed topology has merits like minimum total standing voltage, switching redundancy and inherent polarity generation. Furthermore, MATLAB based simulations and experimental analysis is done to validate the superior performance the proposed topology. The experimental results for the proposed seven-level inverter are presented and discussed in brief by considering different types of loads, amplitude modulation variations and frequency variations.

A bidirectional resonant CLLC converter combining three‐level characteristic and bipolar DC structure

SummaryIn order to meet the efficient and convenient usage requirements for bidirectional DC‐DC converters in some fields such as DC microgrids and vehicle power conversion systems, a bidirectional resonant CLLC converter combining three‐level characteristic and bipolar DC structure is used and analyzed in this paper. A three‐level topology is adopted in the resonant CLLC converter, which can achieve stable and wider range voltage regulation through the frequency adjustment combined with duty cycle and phase shift modulation, and can also increase the flexibility of control strategy. The application of bipolar DC structure enables this resonant CLLC converter to have multi‐port on one side, and the method of using two interleaved inductors combined with synchronous rectification enables the output voltage of the converter to maintain a certain balance. In this paper, the voltage gains and running states of the three‐level regulation method are analyzed, and then these operation modes and the bipolar DC voltage balance effect of the converter under synchronous rectification control are verified by the experiment results.

Clustered Voltage Control and Modulation Scheme With Switching Loss Reduction for High Power Hybrid Cascaded Converter

The hybrid cascade converters (HCC) is a potential solution to achieve harmonic current compensation in medium and high voltage applications due to the characteristics of having high frequency module. However, the high switching frequency inevitably leads to an increase of undesirable switching loss. In addition, since the reduction of power loss and the balance of clustered voltage are mutually interrelated, the existing modulation and control schemes cannot cope with them decently. To address this problem, the HCC is divided into a high-frequency module (HFM) and a low-frequency module (LFM), and a corresponding hybrid modulation scheme is proposed to reduce the power loss while maintaining a high harmonic compensation performance. Then, based on the analysis of the system voltage constraints, the dc-link voltage and threshold voltage under different parameters are redesigned. Furthermore, since the power flow between modules has been changed with the hybrid modulation scheme, the conventional clustered voltage control strategy is not capable of clustered control. Therefore, based on the re-modeling of the power flow, a negative-sequence voltage injection control strategy is proposed to achieve voltage balance. Finally, simulation and experimental results are demonstrated to verify the effectiveness of the proposed scheme.