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The circuit performance of conventional active neutral point-clamped (ANPC) inverter is widely accepted in many renewable energy-based applications like photovoltaic (PV) or electric vehicle grid-connected systems. This is mainly because of its excellent characteristics in terms of voltage/current stress profile of the switches, bidirectional power flow capability, and efficient operation. Nonetheless, due to its half-dc link voltage utilization in the ac output voltage, another power processing stage with additional active and passive elements is required to make its output voltage compatible with the grid when low and wide varying input dc source is available. In this paper, a novel ANPC-based five-level (ANPC5L) inverter with a single-stage boost-integrated circuit design is presented. The proposed topology is able to make the peak output voltage of the conventional ANPC5L inverter followed by a front-end bidirectional boost converter double using the same number of power switches but with less total standing voltage across semiconductors. The working principles of the proposed topology is discussed. Experimental results obtained from 1.3 kW laboratory-built prototype under the grid-connected condition are also given to support the discussion.

Transfomerless grid-connected inverters with common-grounded circuit architectures and single-stage dy-namic voltage boosting gain are promising candidates for PV energy conversion applications. In this work, a new five-level (5L) variant of this category of inverters is introduced. Key features of the presented inverter are the reduced current stress profile, modularity, uniform peak voltage stress across the switches, higher power handling capability, and bi-directional power flow operation. The proposed topology is comprised of two input inductors, two capacitors, and ten power switches. Through a modular design with a phase-shifted SPWM technique, the injected grid current can be shared among the modules, while the size of the grid-interface filters can be reduced. The working principle of the converter is discussed, and some simulation and experimental results are presented to validate its feasibility.

The switched-capacitor-based cascaded multilevel inverters (CMI) have been emerging due to their voltage boosting capability. Unfortunately, they suffer from impulse charging current and nonuniform operation. This article presents a topology termed as dual-T-type five-level CMI to resolve these problems without compromising the desirable voltage boosting characteristic. The main idea is to integrate a half bridge and an inductor to soft charge a capacitor that is connected in series with the dc source. The capacitor enables the voltage gain boosted to two, while the control of eight power switches that constitutes a dual-T structure enables five voltage levels generation. In addition, uniform operation is achieved for cascaded extensions. The operating principle of the proposed topology is analyzed and elaborated. For validation, simulation, and experimental results of a prototype are presented.

Conventional active-neutral-point-clamped (ANPC) inverters exhibit low voltage gain that inherently leads to a high dc-link voltage requirement. An improved ANPC inverter that is capable of generating five voltage levels has recently reduced the dc-link voltage twofold to achieve unity gain. This led to the development of a single-stage dc–ac power converter with no frontend boost dc–dc converter. This article proposes novel ANPC inverters capable of unity or boosted voltage gain while generating higher voltage levels. The first topology can provide a voltage gain of 1.5 and extends the number of levels to seven by incorporating only one additional switch. The topology can also be extended by adding three switches and one floating capacitor to generate nine levels with unity voltage gain, or 11 levels with a voltage gain of 2.5. The proposed ANPC inverters and their operations are comprehensively discussed. Experimental results are provided to validate the feasibility of the proposed ANPC inverters.

Direct torque control (DTC) suffers from flux droop owing to the long zero-voltage vectors at low motor speeds. Previous studies were able to attain flux regulation by imposing the continuous switching of forward and reverse active-voltage vectors by causing torque overshoots in the torque hysteresis bands (THBs). This led to an excessive increase in the switching frequency and larger torque and current ripples, thus reducing the drive efficiency. In this paper, a modified flux regulation method is proposed for the classical DTC using a single THB when flux droop occurs in a low-rotor-speed range. The proposed method can protect the DTC from flux droops at low speeds by reducing the duration of zero-voltage vectors and minimizing the number of reverse-voltage vectors. In addition, the proposed strategy is efficient in reducing torque and current ripples while operating at low motor speeds. Furthermore, a significant reduction in the switching frequency is obtained. The effectiveness of the proposed strategy is confirmed by simulation and experimental results.

Recently multilevel inverters (MLIs) have received wide attention from industry and academia, as they are changing into a viable technology for diverse applications. To produce high-quality output using less switch count, development of novel reduced switch MLI (RS MLI) topologies has been a focus of current research theme. This paper presents design and control of a switched-diode dual source single switch MLI (SDDS MLI). The generalized SDDS MLI is first designed using an asymmetric basic unit. Proposed SDDS MLI requires less switch count and driver circuit count compared with the few recently developed RS MLI topologies. To improve the voltage quality by eliminating targeted low-order harmonics, a modified version of fish swarm optimization algorithm is examined for computing optimum switching angles required to control the SDDS MLI. Moreover, suitability and superiority of the derived algorithm are established by comparing with traditional selective harmonic elimination techniques. The developed topology is investigated through several MATLAB simulations as well as experimental tests in the laboratory applying the modified control approach.

This paper proposes a new family of multilevel inverter topology that is able to generate seven voltage levels by utilizing one or two floating capacitors and 10 power switches. This novel boost switched-capacitor seven-level inverter possesses voltage boosting capability with an achievable maximum voltage level 1.5 times the input direct current (dc) voltage. The generation of higher output voltage does not incur high-voltage stress on any power switch in this topology, as the peak inverse voltages of all power switches do not exceed the input source voltage. In addition, capacitor voltage balancing is not essential since the floating capacitors are effectively balanced during the charging and discharging processes. Furthermore, the proposed topology eliminates the need for multiple isolated dc sources, and a single dc source is sufficient in both its single-phase and three-phase topologies. The operating principle and steady-state analysis of the proposed topology are elaborated. Experimental results from a single-phase prototype are then presented to verify the validity of the proposed topology.

Transformerless (TL) grid-connected photovoltaic (PV) inverters with a common-ground (CG) circuit architecture exhibit some excellent features in removing the leakage current concern and improving the overall efficiency. However, the ability to cope with a wide range of input voltage changes while maintaining the output voltage in a single power conversion stage is a key technological challenge. Considering this, the article at hand proposes a novel dual-mode switched-capacitor five-level (DMSC5L)-TL inverter with a CG feature connected to the grid. The proposed topology is comprised of a single dc source and power diode, three capacitors, four unidirectional, and three bidirectional power switches. Based on the series-parallel switching conversion of the involved switches, the proposed DMSC5L-TL inverter can generate five distinctive output voltage levels during both the boost and buck operation modes with a self-voltage balancing operation for the involved capacitors. A simple dead-beat continuous current controller (DB3C) modulation technique is also used to handle both the active and reactive power exchange while ensuring a fixed switching frequency operation. The proposed circuit description with its DB3C details, the design guidelines with a comparative study, and some experimental results are also given to show the feasibility of the proposed solution for the practical applications.

Single-source inverters with integrated switched-boost (SB) module and single-stage energy power conversion architecture have become a popular solution in many power electronics applications. This paper presents a novel topology of such types of inverters, which offers a modular design with a dynamic voltage boosting feature over a wide range of input voltages. The basic configuration of the proposed topology is able to generate three output voltage levels. It is comprised of an integrated SB module and a Quasi-H-Bridge (QHB) cell. The QHB cell consists of a self-balanced floating capacitor and four power switches, and the SB cell consists of a boost inductor and a single power switch. A five-level boosted output voltage can be achieved through the differential connection of two identical QHB cells utilizing a single SB module. The circuit description of the proposed topology, a comparative study, and the simulation and measurement results are given to verify the feasibility of this proposal.

Dynamic voltage boosting feature in photovoltaic (PV) grid-integrated application is a necessity to achieve the maximum power point of PV arrays as well as boost the input voltage to the necessary dc-link voltage requirement. Such feature is usually achieved by incorporating a front-end boost or buck-boost dc-dc converter tendem with a conventional two or three-level inverter. However, such an integration cannot efficiently meet many IEEE strict grid codes from the power quality, ground leakage current, and the overall efficiency per power density aspects. The aim of this paper is to present a new five-level (5L) inverter with an integrated single-stage dynamic voltage-boosting concept and a common-grounded (CG) feature. As a result, the concern of ground leakage current is addressed through the provided CG feature, whilst both the power quality and overall efficiency of the system are improved with a 5L single-stage boosted output voltage waveform. To confirm the effectiveness of the proposal, apart from the circuit description, some experimental results are also presented.

This article presents a novel cascaded multilevel inverter as an alternative to the cascaded H-bridge (CHB). By adopting two H-bridges integrated with two inductors and two power switches, the proposed topology is able to generate a five-level voltage with merely a single dc source. Voltage-boosting capability is guaranteed despite its single-stage operation. A corresponding modulation technique is also established to charge the boost inductors with a constant duty-cycle while simultaneously generating a five-level ac voltage. Therefore, the proposed topology outperforms the CHB in reducing the isolated dc source count, enhancing the voltage gain, and lowering the dc source voltage magnitude. In addition, the modularity is preserved, where the proposed topology can be extended by cascading multiple modules. The operation and feasibility of the proposed cascaded multilevel inverter is analyzed and validated through simulation and experimental results.

Single-stage inverters with a common ac and de ground are emerging topologies which effectively eliminate the high-frequency common mode voltage. However, most of the existing common-ground-type inverters are based on switched-capacitor (SC) circuits which are inherently subjected to several important issues that lead to many practical limitations. Disadvantages such as high current spikes, high capacitor voltage ripples, and distorted ac output voltage with de offset are some significant challenges in these inverters. A new common-ground-type inverter that discard the use of SCs is therefore proposed in this paper. It consists of a single-inductor and an ac output capacitor that are controlled by 8 power switches. Sinusoidal ac voltage generation in both buck and boost modes can be achieved by controlling the inductor with a sinusoidal duty-cycle. Simulations are presented to verify the operation of the proposed topology.

This paper proposes a method to implement gain-scheduled adaptive PI control of wireless charging series-series resonant converter duty cycle control at fixed switching frequency operation. The method is applicable for both voltage mode battery charging control and current mode battery charging control. The gain scheduled PI controller look-up tables are established based on the optimized frequency domain control loop design in the entire equivalent load resistance variation range for the full battery charging cycle including both current mode charging operation and voltage mode charging operation for the voltage mode control. The same gain-scheduled PI control look-up tables are applied for the current mode battery charging control with additional loop gain applied for battery equivalent load resistance variation compensation. In both voltage mode and current mode control scheme, the DC input voltage magnitude variation and the non-linear gain of duty cycle command are both compensated so that the control system performance will not be affected by operation condition changes of DC input voltage and duty cycle level. The proposed gain scheduled PI control ensures that uniformed control loop bandwidth and satisfactory dynamic responses are achieved with sufficient stability margins in the wide range of equivalent load resistance change required for battery charging profile optimization.

The authors intent using a boost multi-level converter for the doubly fed induction machine (DFIM) used in variable-speed pumped storage plants (VS-PSP). Voltage-source converters connected on the rotor side of the machine control the active and reactive powers of the unit. The proposed boost neutral point clamped (NPC) converter topology provides a voltage output two times larger than a conventional three-level NPC (3L-NPC) with similar DC-link voltage and equal number of switches. Hence, it increases the speed variation of the unit, which improves the efficiency during generation and pumping modes. Moreover, it reduces the starting period of the unit at the pumping mode, which is significant during mode changeover time. Furthermore, it reduces switching and conduction losses in the converter. It also reduces the total harmonic distortion in the output current, as it provides five output voltage levels. These improvements show that the boost NPC converter topology is better among VS-PSP project authorities. In addition, the reliability of the proposed topology is investigated, where converter redundancy is a challenging issue in asynchronous VS-PSP units. The proposed boost NPC was compared with the conventional 3L-NPC system by examining a 250 MW DFIM hydro-generating unit.

The conventional three-level active-neutral-point-clamped (ANPC) inverter requires high dc-link voltage at least twice the peak of ac output. To reduce the dc-link voltage, a recent topology that enhanced the voltage gain from half to unity has been presented. In this letter, an alternative ANPC topology is established by using two T-type inverters. Two floating capacitors with self-voltage balancing capability are integrated to achieve a voltage-boosting gain of 1.5. In addition, the proposed topology is capable of generating seven voltage levels. Its operation is validated through circuit analysis followed by experimental results of a prototype.

This paper presents the rapid prototyping and validation of a Three-Phase Silicon Carbide (SiC) Voltage Source Inverter (VSI) in open-loop control and closed-loop control in TI C2000 microcontroller using PLECS coder real-time control tool. Comparative studies are also conducted to study the crucial factors that impacts the performance of the inverter. In open loop control, the experiment on the effect of using different PWM control strategies in terms of changing the modulation index was investigated. While in closed loop, the verification of the feedback of the PI control were studied to ensure that the output was able to maintain at the desired output level. The simulation results are compared with the hardware measurement results to validate the open and closed loop operations of the inverter. The 3-phase voltage source inverter rapid prototyping hardware platform developed is applicable for university lab teaching and advanced inverter control feature development.

This paper proposes the method to analyze the performance of wireless charging DC/DC resonant converters in various load conditions including the magnetic coupling effect. The equations for design performance analytical calculations are presented for series-series (SS) and series-parallel (SP) wireless charging DC/DC resonant converters. The equations can be applied in switching frequency sensitivity analysis at different magnetic strength and load resistance conditions to compare the performance of the resonant circuit topologies. The analytical calculation results can be used to size the voltage, current, and power rating of wireless charging resonant circuit components. The accuracy of the analytical calculation is validated by duty cycle control of wireless charging resonant converters in PLECS circuit simulation environment. Experimental results are obtained to support the conclusion drawn from the analytical solutions. The proposed method can be applied to study other wireless charging resonant converter topologies.

Switched-capacitor (SC) based inverter topologies are very attractive for renewable energy applications to step-up low dc voltage to higher ac voltage in single-stage without the need of front-end dc-dc converters, thus improving overall system efficiency, reliability and power density. This paper presents a new modular multilevel inverter based on switched-capacitor technique. Herein, series-parallel conversion technique is utilized to effectively self-balance the switched-capacitor voltages. Compared to other latest SC-based MLIs topology, the proposed structure features several advantages such as: low number of conducting semiconductor devices in load current paths and SC Charging paths. In addition, each capacitor is charged for at least half of the fundamental period that reduces voltage ripple and improves the inverter efficiency. Consequently, the presented inverter is suitable for high levels generation to achieve the rated ac voltage directly from a low voltage dc source. The merits and feasibility of the proposed inverter are verified through simulation for seven levels with sinusoidal PWM at different modulation indices and load conditions.

This paper presents the modelling and simulation of an 80kW AC microgrid network in MATLAB/Simulink environment. The network comprises a 50 kW photovoltaic system, a 10 kW fuel cell system, and a 20 kW battery energy storage system (BESS). The model is simulated under four operating conditions: (i) grid-connected mode, (ii) islanded mode (iii) islanded mode with excess power generation from Distributed Energy Resources (DERs) and (iv) islanded mode with limited power generation from DERs. Simulation results of the microgrid during various operating conditions were observed to investigate the charging and discharging characteristics of the battery and the total harmonic distortion of the power network during grid-connected mode and islanded modes.

In this paper, a novel 5-level inverter with common ac and dc ground is proposed for solar photovoltaic (PV) applications. The newly established common-ground-T-type (CGT-type) inverter is a single-stage topology restructured from the combination of a classical T-type inverter and a front-end three-level boost converter. Its distinctive topological structure can effectively eliminate the common mode voltage issue, prevent leakage currents, and ensure a continuous input current in PV systems. More importantly, it requires only two capacitors to realize an ac voltage which can be significantly boosted from a single dc source. A pulse width modulation (PWM) scheme is also established to undertake the following tasks simultaneously: charging of the boost inductor with a constant duty-cycle, and switching of two capacitors for 5-level ac voltage generation. The operation and feasibility of the proposed CGT-type inverter is analyzed and validated through simulation results.

This paper explores the feasibility of multilevel dual-active bridge-inverter (DABMI) applications for grid-connected applications of a modern Model of Predictive Direct Power Control (MPDPC) based on the conservative power theory (CPT). In the case of unbalanced grid voltages, the objective of the study is to promote continued active and reactive energy in MPDPC without reducing efficiency such as transient response and current harmonics. The nature of the instantaneous p-q theory permits only one out of three control targets to be fulfilled. The proposed control approached directly regulates the instantaneous active and reactive power to achieve three particular control objectives namely sinusoidal and symmetrical grid current, cancelling twice of fundamental grid frequency reactive power ripples, and removing twice grid frequency active power ripple. The techniques of complicated Grid part sequence extraction are unnecessary and improved at no extra expense, as is the case with current MPDPC fault-tolerant approaches. The instantaneous power at the next sampling instant is predicted with the newly developed discrete-time model. Each possible switching state will then be evaluated in the cost function defined until the optimal state which lead to the minimum power errors is determined. In MATLAB/Simulink simulation, the proposed CPT-based MPDPC measures reliability and performance at balanced and unbalanced grid voltages then compared with the conventional and existing MPDPC The proposed method manages to achieve all of three control targets which generates sinusoidal grid currents and attenuates active and reactive power ripple of twice the grid frequency exactly at the same time without losing its critical efficiency including transient reaction and current harmonics.

SUMMARYUp to 30% of thyroid nodules cannot be accurately classified as benign or malignant by cytopathology. Diagnostic accuracy can be improved by nucleic acid-based testing, yet a sizeable number of diagnostic thyroidectomies remains unavoidable. In order to develop a protein classifier for thyroid nodules, we analyzed the quantitative proteomes of 1,725 retrospective thyroid tissue samples from 578 patients using pressure-cycling technology and data-independent acquisition mass spectrometry. With artificial neural networks, a classifier of 14 proteins achieved over 93% accuracy in classifying malignant thyroid nodules. This classifier was validated in retrospective samples of 271 patients (91% accuracy), and prospective samples of 62 patients (88% accuracy) from four independent centers. These rapidly acquired proteotypes and artificial neural networks supported the establishment of an effective protein classifier for classifying thyroid nodules.

To answer the increasing need for detecting and validating protein biomarkers in clinical specimens, proteomic techniques are required that support the fast, reproducible and quantitative analysis of large clinical sample cohorts. Targeted mass spectrometry techniques, specifically SRM, PRM and the massively parallel SWATH/DIA technique have emerged as a powerful method for biomarker research. For optimal performance, they require prior knowledge about the fragment ion spectra of targeted peptides. In this report, we describe a mass spectrometric (MS) pipeline and spectral resource to support data-independent acquisition (DIA) and parallel reaction monitoring (PRM) based biomarker studies. To build the spectral resource we integrated common open-source MS computational tools to assemble an open source computational workflow based on Docker. It was then applied to generate a comprehensive DIA pan-human library (DPHL) from 1,096 data dependent acquisition (DDA) MS raw files, and it comprises 242,476 unique peptide sequences from 14,782 protein groups and 10,943 SwissProt-annotated proteins expressed in 16 types of cancer samples. In particular, tissue specimens from patients with prostate cancer, cervical cancer, colorectal cancer, hepatocellular carcinoma, gastric cancer, lung adenocarcinoma, squamous cell lung carcinoma, diseased thyroid, glioblastoma multiforme, sarcoma and diffuse large B-cell lymphoma (DLBCL), as well as plasma samples from a range of hematologic malignancies were collected from multiple clinics in China, the Netherlands and Singapore and included in the resource. This extensive spectral resource was then applied to a prostate cancer cohort of 17 patients, consisting of 8 patients with prostate cancer (PCa) and 9 with benign prostate hyperplasia (BPH), respectively. Data analysis of DIA data from these samples identified differential expressions of FASN, TPP1 and SPON2 in prostate tumors. Thereafter, PRM validation was applied to a larger PCa cohort of 57 patients and the differential expressions of FASN, TPP1 and SPON2 in prostate tumors were validated. As a second application, the DPHL spectral resource was applied to a patient cohort consisting of samples from 19 DLBCL patients and 18 healthy individuals. Differential expressions of CRP, CD44 and SAA1 between DLBCL cases and healthy controls were detected by DIA-MS and confirmed by PRM. These data demonstrate that the DPHL supported that DIA-PRM MS pipeline enables robust protein biomarker discoveries.

The conventional active neutral-point-clamped (ANPC) inverter inherits excellent high-frequency common mode voltage (CMV) mitigation ability but with a restricted voltage gain. This letter proposes a novel five-level ANPC inverter that is able to accomplish voltage-boosting within a single-stage dc–ac power conversion. A common ground in the proposed topology not only mitigates the high-frequency CMV but also enhances the dc-link voltage utilization. The proposed topology exhibits lower voltage stresses and higher compactness when compared with a conventional two-stage five-level ANPC inverter. The proposed inverter saves three power switches and one capacitor while enhancing the overall efficiency. Simulations and experimental tests have validated the overall operation, efficacy, and practicality of the proposed ANPC inverter.

The active neutral-point-clamped (ANPC) inverter is a popular multilevel inverter for various industry applications. In a recent attempt, an improved topology that integrates a flying capacitor to enhance the voltage gain from half to unity has been presented [11]. Retaining the benefit of unity-gain, this paper proposes a new ANPC topology with two improvements. Firstly, the voltage stress of the flying capacitor is reduced by half. Secondly, the charging of the flying capacitor at 0 level is made possible to achieve uniform charging over the power cycle. Comprehensive analysis is presented and experimental results of a prototype are presented for validation. Finally, the extension of the topology with increased number of output voltage levels generation is briefly discussed.

A new family of 7-Level Boost Active Neutral Point Clamped (7L-BANPC) circuits is proposed in this paper. The proposed topology is derived from the conventional ANPC by adding one additional capacitor to boost the voltage and increase the number of output voltage levels. The proposed topology generates seven output voltage levels using one dc source and two flying capacitors. A specific modulation strategy is presented in this study to provide self-balancing for the flying capacitors of the proposed inverter. Theoretical analysis and the operational modes of the proposed 7L-BANPC are presented in this paper. Highlights of the simulation of the proposed inverter are presented to validate the proposed topology. A scaled-down prototype has been built to validate the workability of the proposed topology.

Cascaded H-bridge (CHB) multilevel inverters (MLIs) have been widely used for power electronics systems. While high-voltage blocking across power switches is not a constraint for low voltage applications, the research trend has been oriented to the design of more compact module topologies as an alternative for CHB. Despite the generation of more voltage levels with reduced switch count, the existing module topologies in recent literature take no account of the freewheeling current path during dead-time, thus, inducing multistep jumps in voltage levels and giving rise to undesirable voltage spikes. Addressing this concern, this paper proposes two symmetrical compact-module topologies for cascaded MLI, where freewheeling current path during dead-time is provided for smooth transition between voltage levels to prevent voltage spikes. The proposed 7-level and 13-level compact-modules demonstrated low number of conducting switches for all voltage levels. Comprehensive analysis and comparison with the latest module topologies are conducted. To validate the operation of the proposed compact-module topologies, simulation and experimental results are presented.

Genetically modified FVIII‐expressing autologous bone marrow‐derived mesenchymal stromal cells (BMSCs) could cure haemophilia A. However, culture‐expanded BMSCs engraft poorly in extramedullary sites. Here, we compared the intramedullary cavity, skeletal muscle, subcutaneous tissue and systemic circulation as tissue microenvironments that could support durable engraftment of FVIII‐secreting BMSC in vivo. A zinc finger nuclease integrated human FVIII transgene into PPP1R12C (intron 1) of culture‐expanded primary canine BMSCs. FVIII‐secretory capacity of implanted BMSCs in each dog was expressed as an individualized therapy index (number of viable BMSCs implanted × FVIII activity secreted/million BMSCs/24 hours). Plasma samples before and after implantation were assayed for transgenic FVIII protein using an anti‐human FVIII antibody having negligible cross‐reactivity with canine FVIII. Plasma transgenic FVIII persisted for at least 48 weeks after implantation in the intramedullary cavity. Transgenic FVIII protein levels were low after intramuscular implantation and undetectable after both intravenous infusion and subcutaneous implantation. All plasma samples were negative for anti‐human FVIII antibodies. Plasma concentrations and durability of transgenic FVIII secretion showed no correlation with the therapy index. Thus, the implantation site microenvironment is crucial. The intramedullary microenvironment, but not extramedullary tissues, supported durable engraftment of genetically modified autologous FVIII‐secreting BMSCs.

This letter proposes an improved symmetrical 4-level submodule as a basic cell for generating multiple dc voltage levels. A hybrid cascaded multilevel inverter (HCMLI) topology is formed by the combination of n submodules and a full-bridge. A comparative analysis against the recent multilevel inverters reveals that the proposed topology requires less number of switches and dc sources. In addition, the proposed submodule reduces the number of conducting switch and gate driver requirements compared to the widely used half-bridge submodule. To validate the operation of the proposed HCMLI topology, experimental results of a 9-level single-phase inverter controlled by selective harmonic elimination pulse-width-modulation is presented.

This paper focuses on a tuning-less model predictive control (MPC) strategy with unbalanced fault-ride-through capability for a three-phase modular multilevel converter (MMC). Three individual control stages are designed to cater for the multiple control objectives in MMC without the need for any weighting factor tuning. A conceptually simple power regulation approach which requires neither synchronous coordinate transformation nor grid-voltage phase angle detection is introduced into the proposed MPC. Meanwhile, two alternatives are proposed to the power regulation stage to adapt to the special needs under unbalanced grid fault. Neither of the alternatives involves any tuning work. In addition, a modified sorting algorithm is presented to resolve the problem of unnecessary switching transitions, which is inherent in conventional sorting algorithm. The proposed tuning-less MPC is capable of direct active and reactive power control, circulating current minimization, submodule capacitor voltage balancing, switching frequency reduction, and great resilience under balanced and unbalanced grid conditions. The presented simulation results confirm the effectiveness and feasibility of the proposed control method.

This paper proposes two improved cascaded H-bridge (ICHB) multilevel inverters that feature voltage-boosting capability. The conventional H-bridge with a front-end dc–dc boost converter was restructured for single-stage operation. The developed three-level topology not only saves one power switch but also exhibits lower voltage stress across its capacitor. Extension to five-level generation was also introduced by merely adding two power switches and one capacitor. The final five-level topology outperforms the classical cascaded H-bridge (CHB) multilevel inverter with a significant reduction in the power switch count, with a 42% and 50% reduction in both the isolated dc source and inductor counts. The power efficiency was also improved without compromising the modularity feature of the classical CHB multilevel inverter. The operation and theoretical analysis of the proposed topologies were validated via simulations and experimental tests.

The grid connected renewable sources with their inherent intermittent behavior are inevitably imposing significant challenge to the controller design of the voltage source converters. Majority of the control approaches have ambiguous statements in relation to their performances under non ideal grid voltage conditions which is prevalent in renewable energy integrated weak micro-grid system. On that account, this paper provides a comprehensive overview of the existing table-based direct power control (DPC) schemes and review of their performance on the basis of power tracking and total harmonic distortion (THD) of the grid current under various grid conditions. In order to mitigate the drawback of the existing table-based DPC which result in high current THD under unbalanced or distorted voltage supply, this paper also proposed a novel concept of table-based DPC which adapted the extension pq theory into the virtual flux-based DPC. The feasibility of the proposed resilient virtual flux-based DPC (RVF-DPC) is verified by using MATLAB/Simulink and a comparative study is conducted to evaluate the superiority of the proposed controller with another three representative table-based DPC schemes. Simulation results have shown that, for an increased degree of unbalance and distortion of grid voltages, the proposed RVF-DPC is able to maintain the total harmonic distortions of the grid currents to a certain extent while keeping the constant power tracking performance.

This paper proposes a novel voltage level-based predictive direct power control (PDPC) strategy integrated with voltage sorting algorithm for a three phase grid-connected modular multilevel converter (MMC). The main advantage of the proposed control strategy, compared with the predictive current controllers, is that it does not need angular information of grid parameters. Therefore, it is simpler and able to get rid of rotary transformation and inner current loop. Contrary to the phase-by-phase control in predictive current controllers, the proposed control scheme advocates three-phase control. As a result, it achieves significant improvement in terms of smaller power ripples, more accurate tracking of power references, and less current harmonics. Further study reveals that the proposed voltage level-based PDPC exhibits less switching frequency irrespective of the magnitude of power references and power angles. Meanwhile, the capability of capacitor voltage balancing control and circulating current control in the proposed PDPC is as good as in the predictive current controllers. Some in-depth simulation comparisons with one of the existing predictive current controllers are given to validate the effectiveness of the proposed strategy.

Chromosomal rearrangements are common in cancer. More than 50% occur in common fragile sites and disrupt tumor suppressors. However, such rearrangements are not known in gastric cancer. Here we report recurrent 18q2 breakpoints in 6 of 17 gastric cancer cell lines. The rearranged chromosome 18, t(9;18), in MKN7 cells was flow sorted and identified by reverse chromosome painting. High-resolution tiling array hybridization mapped breakpoints to DOK6 (docking protein 6) intron 4 in FRA18C (18q22.2) and an intergenic region in 9q22.2. The same rearrangement was detected by FISH in 22% of 99 primary gastric cancers. Intron 4 truncation was associated with reduced DOK6 transcription. Analysis of The Cancer Genome Atlas stomach adenocarcinoma cohort showed significant correlation of DOK6 expression with histological and molecular phenotypes. Multiple oncogenic signaling pathways (gastrin-CREB, NGF-neurotrophin, PDGF, EGFR, ERK, ERBB4, FGFR1, RAS, VEGFR2 and RAF/MAP kinase) known to be active in aggressive gastric cancers were strikingly diminished in gastric cancers with low DOK6 expression. Median survival of patients with low DOK6-expressing tumors was 2100 days compared with 533 days in patients with high DOK6-expressing tumors (log-rank P = 0.0027). The level of DOK6 expression in tumors predicted patient survival independent of TNM stage. These findings point to new functions of human DOK6 as an adaptor that interacts with diverse molecular components of signaling pathways. Our data suggest that DOK6 expression is an integrated biomarker of multiple oncogenic signals in gastric cancer and identify FRA18C as a new cancer-associated fragile site. Gastric tumors often harbor a chromosome abnormality that disrupts a key signaling gene, resulting in less aggressive cancers. Oi Lian Kon from the National Cancer Centre Singapore and colleagues searched for chromosomal rearrangements in 17 gastric cancer cell lines. The researchers discovered a recurrent breakpoint in six of the cell lines that mapped to a gene called DOK6, which encodes a protein that provides a docking platform for multiple signaling molecules. They also found the abnormality in 22 of 99 tissue samples taken from gastric cancer patients. This defect led to lower expression of DOK6 and, in turn, less active oncogenic signaling pathways. Patients with low DOK6-expressing gastric cancers lived longer on average than those with high DOK6-expressing tumors. The findings point to DOK6 levels as a potential drug target and diagnostic biomarker.

In this article, an optimal virtual flux predictive direct power control (VF-PDPC) is proposed for three-phase grid connected voltage source inverter (VSI) operating under unbalanced and distorted grid supply voltage. The concept of virtual flux and extension pq theory is introduced in the conventional PDPC, where the former enhances its resilience toward distorted supply voltage while the latter enhances its resilience toward unbalanced supply voltage. The inherent advantages of the conventional PDPC scheme, such as simple implementation, fast dynamic responses, and no demand of modulators are retained. Getting rid of the complicated positive and negative sequence extraction of grid components, power compensation, or any tuning work, the proposed optimal VF-PDPC achieves excellent power tracking capability, and sinusoidal grid currents with low harmonics under various grid voltage conditions. Simulation results are presented to verify the effectiveness of the proposed control scheme when compared to the conventional PDPC, conventional VF-PDPC, and optimal PDPC.

This paper deals with the design and simulation of Dual Active Bridge Multilevel Inverter (DABMI) based Model Predictive Direct Current Control (MPDCC) for grid connected application. To achieve multilevel output voltage waveforms, the second inverter will be supply with half of the dc-link voltage. Model predictive direct current control used to control the grid current component in order to achieve minimum grid current error. Modulation is unnecessary in this system because the switching pattern is produce by the possible switching that determined by the proposed MPDCC. The voltage vector which minimizes the cost function will be selected and applied to track the reference current. The performance of the proposed MPDCC is observe and implement by MATLAB/Simulink Software.

This paper presents a new transformerless inverter topology which is termed as a single-stage common-ground boost inverter (S2CGBI) for single-phase solar photovoltaic (PV) systems. The proposed topology provides a common-ground for both the dc source and ac output to eliminate the leakage current induced by the parasitic capacitance of PV cells. Voltage-boosting is made possible with the incorporation of only one inductor, which renders the realization of single-stage power conversion. The proposed pulse width modulation (PWM) technique is capable of charging the inductor with a constant duty-cycle while guaranteeing ac output generation. The operation of the proposed S2CGBI is analyzed. Simulation and experimental results are provided to validate the effectiveness of the proposed topology and modulation scheme.

This paper presents a comparative study of the proportional-integral-based (PI-based) synchronous current control strategy with derivative-feedback-based active damping and the finite-control-set model-predictive-control-based (FCS-MPC-based) synchronous current control strategy with cost-function-based active damping. For a fair comparison, the sensor requirement and the average switching frequency of FCS-MPC are made equivalent to that of the pulse-width-modulation-based counterpart through internal model estimation and control sampling frequency adjustment. The comparative study considers gain/weighting-factor tuning, delay compensation, switching harmonics, and active damping performance at the critical frequency operating point. The overall performance of both schemes is validated through the same experimental setup and test scenarios. The results conclude that the emerging FCS-MPC has the potential to produce similar results as the classical PI-based counterpart while carrying some practical features. These include being intuitive in active damping design and tuning, guaranteeing fast dynamics, and being sufficiently robust to grid impedance shifting. These findings essentially justify the potential of model predictive control being a viable alternative for this area of application.

Thiopurines are used in the treatment of inflammatory bowel disease (IBD) but remain clinically challenging to manage due to wide interpatient variability in clinical outcomes and adverse events. Apart from genetic variants in thiopurine S-methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15) genes, polymorphisms in FTO alpha-ketoglutarate dependent dioxygenase (FTO) were found predictive of thiopurine-induced leukopenia, albeit with conflicting results. To clarify the role of FTO variants in a multiethnic Asian IBD cohort, we recruited 149 patients on thiopurine-based therapy and genotyped two FTO variants p.Ala134Thr (rs79206939) and rs16952570 T C using Sanger sequencing. FTO p.Ala134Thr (rs79206939) was non-polymorphic and absent whereas intronic rs16952570 T C was equally prevalent in Chinese (22%) and Indians (18%) and higher in Malays (28%). Higher nadir white blood cell (WBC) and absolute neutrophil count (ANC) levels were observed in patients harboring FTO rs16952570 CC genotypes compared with TT carriers at 4, 8, and 12 weeks after start of thiopurine therapy (P 0.05). A similar trend was observed in patients carrying the previously well-characterized NUDT15 rs116855232 wild-type CC genotypes. Further in silico analysis suggests that FTO variants linked to rs16952570, particularly rs74018601, may play a regulatory role in altering the FTO expression. The findings from this study indicate a novel protective association with the FTO variant rs16952570 CC genotype and hematological parameters.

Double fed induction machine (DFIM) is preferred in various industrial applications, as it provides variable speed operation with reduced power converter rating and high dynamic stability. On rotor side, back-to-back voltage source converter (VSC) is act as excitation system and controls real and reactive power of the machine. Boost multi-level neutral point clamped (NPC) VSC is emerging in industrial applications due to the high dc link voltage utilization and less current THD. Full power converter redundancy in large rated VSC fed DFIM is challengeable and it is not yet employed in any practical applications such wind power generation and pumped-hydro power units. Therefore, fault-tolerant control (FTC) of VSC is mandatory for the continuous operation of unit by the project authorities of the units. This paper presents the fault tolerant and reconfiguration control approach for a boost NPC converter fed DFIM unit at open circuit faults in all controlled switches/devices. FTC during open-switch faults are investigated with the help of converter output voltage. Fault detection and isolation is achieved through the rotor currents and dc link voltage. A 2 MW DFIM is simulated in Matlab/Simulink environment to verify the operation of the proposed fault tolerant control.

This paper presents a three-phase off-board charger for plug-in electric vehicles (PEV) with model predictive direct power control (MPDPC) for PEV battery charging. In the paper, the system description of the PEV charger is explained and its control is thoroughly discussed. Then, the steady-state characteristics of the charger is verified using MATLAB Simulink to confirm the feasibility of the PEV charger using MPDPC. Results show good power delivery for battery charging with respect to preset active and reactive power references while providing constant battery charging voltage and current.

A grid-connected PV generator employing three-phase voltage source converter (VSC) controlled using model predictive direct power control (MPDPC) is presented in this paper. The system description of PV generator is explained and its control is thoroughly discussed. Then, the steady-state characteristics of the system is verified using MATLAB Simulink to confirm the practicality of controlling grid-connected PV generator using MPDPC. Maximum power is extracted from the PV array using maximum power point tracking algorithm while the grid compensates the remaining load active power that is required. Results show good power delivery to the load from PV array and the grid.

The single-phase split-source inverter is an emerging and attractive topology for boost dc-ac power conversion system. Such an inverter features high compactness, however, at the expense of high-frequency commutations across diodes. The corresponding hybrid PWM also confines the voltage harmonics to concentrate around the switching frequency and its multiples. This paper proposes a simplified split-source inverter which is realized by inserting only one power switch into an H-bridge. While generating the ac output, the newly developed PWM strategy ensures the inductor charged with constant duty-cycle. When compared to the existing split-source inverters, it offers the added benefits of reduced switch count, enhanced voltage boosting gain, reduced output filter requirement, and enhanced power efficiency. Comprehensive steady-state analysis is discussed while simulation and experimental results are subsequently presented to prove the validity of the proposed topology and the PWM strategy.

Costly coagulation factor VIII (FVIII) replacement therapy is a barrier to optimal clinical management of hemophilia A. Therapy using FVIII-secreting autologous primary cells is potentially efficacious and more affordable. Zinc finger nucleases (ZFN) mediate transgene integration into the AAVS1 locus but comprehensive evaluation of off-target genome effects is currently lacking. In light of serious adverse effects in clinical trials which employed genome-integrating viral vectors, this study evaluated potential genotoxicity of ZFN-mediated transgenesis using different techniques. We employed deep sequencing of predicted off-target sites, copy number analysis, whole-genome sequencing, and RNA-seq in primary human umbilical cord-lining epithelial cells (CLECs) with AAVS1 ZFN-mediated FVIII transgene integration. We combined molecular features to enhance the accuracy and activity of ZFN-mediated transgenesis. Our data showed a low frequency of ZFN-associated indels, no detectable off-target transgene integrations or chromosomal rearrangements. ZFN-modified CLECs had very few dysregulated transcripts and no evidence of activated oncogenic pathways. We also showed AAVS1 ZFN activity and durable FVIII transgene secretion in primary human dermal fibroblasts, bone marrow- and adipose tissue-derived stromal cells. Our study suggests that, with close attention to the molecular design of genome-modifying constructs, AAVS1 ZFN-mediated FVIII integration in several primary human cell types may be safe and efficacious.

Iatrogenic adverse events in clinical trials of retroviral vector-mediated gene-corrected cells have prioritized the urgent need for more comprehensive and stringent assessment of potentially genotoxic off-target alterations and the biosafety of cells intended for therapeutic applications. Genome editing tools such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced palindromic repeats (CRISPR)-Cas9 nuclease systems are being investigated as safer and efficient alternatives for site-directed genome modification. Using site-specific integration into the AAVS1 locus of primary human cells as an example, we present an integrated approach to multimodal investigation of off-target alterations and an evaluation of potential genotoxicity induced by ZFN-mediated integration of a therapeutic transgene.

This paper presents a model predictive control (MPC) for off-board plug-in electric vehicle (PEV) chargers with photovoltaic (PV) integration using two-level four-leg inverter topology. The PEV charger is controlled by a unified controller that incorporates direct power and current MPC to dynamically control decoupled active-reactive power flow in a smart grid environment as well as to control PEV battery charging and discharging reliably. PV power generation with maximum power tracking is seamlessly integrated with the power flow control to provide additional power generation. Fast dynamic response and good steady-state performance under all power flow modes and various environmental conditions are evaluated and analyzed. From the results obtained, the charger demonstrates less than 1.5% total harmonic distortion as well as low active and reactive power ripple of less than 7% and 8% respectively on the grid for all power flow modes. The PEV battery also experiences a low charging and discharging current ripple of less than 2.5%. Therefore, the results indicate the successful implementation of the proposed charger and its control for PV integrated off-board PEV chargers.

A two-stage switched-capacitor based multilevel inverter possesses a drawback such that switches in the second stage (i.e., H-bridge) endure higher voltage stress. To resolve this problem, this letter proposes a single-stage switched-capacitor module (S3CM) topology for cascaded multilevel inverter, which ensures the peak inverse voltage across all the switches within the dc source voltage. A total of nine voltage levels can be generated with only one dc source and two incorporated capacitors. Hence, the number of isolated dc sources is significantly reduced compared to a cascaded H-bridge. In addition, voltage boosting gain of two is achieved. A comparative analysis of the recent topology reveals that the proposed S3CM topology achieves switch count reduction. The operation of the proposed topology is validated through circuit analysis followed by simulation and experimental results of a single-module (9-level) prototype.

Iatrogenic adverse events in clinical trials of retroviral vector-mediated gene-corrected cells have prioritized the urgent need for more comprehensive and stringent assessment of potentially genotoxic off-target alterations and the biosafety of cells intended for therapeutic applications. Genome editing tools such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced palindromic repeats (CRISPR)-Cas9 nuclease systems are being investigated as safer and efficient alternatives for site-directed genome modification. Using site-specific integration into the AAVS1 locus of primary human cells as an example, we present an integrated approach to multimodal investigation of off-target alterations and an evaluation of potential genotoxicity induced by ZFN-mediated integration of a therapeutic transgene.