The cascaded H-bridge (CHB) inverters has drawn much attention in renewable energy and industrial applications. Conventional modulation strategies for CHB inverters face challenges in simultaneously achieving optimal output voltage harmonic characteristics and active power balancing among cascaded units. To address this issue, this article proposes a novel power-balancing modulation strategy based on carrier cycle adjustment for nine-level CHB inverters with full modulation ratio range. The proposed method extends conventional phase disposition modulation by synchronously rearranging the carriers above and below the time axis, thereby creating a new carrier period cycle that can improve the output of internal power units. Within this framework, duty cycle expressions for each cascaded unit are derived, and the corresponding fundamental voltage components are analytically obtained. The analysis demonstrates that the proposed strategy achieves effective power balancing across all cascaded units within a single fundamental cycle. Finally, both simulation and experimental results confirm the effectiveness and practicality of the method.

Although the traditional Phase Disposition (PD) carrier modulation strategy applied to Cascaded H-Bridge (CHB) multilevel inverters offers optimal output voltage harmonic characteristics, it suffers from unbalanced output power among the cascaded units. To address this issue, a novel carrier-adjusted power-balancing modulation strategy is proposed. Targeting a four-unit CHB inverter, this strategy reconstructs new carrier adjustment cycles by modifying the vertical arrangement of standard carriers based on the traditional PD modulation. Detailed derivations are provided for the output voltage expressions and the amplitudes of the fundamental components of all cascaded units across the full modulation ratio range. Analysis from the perspective of fundamental component amplitudes demonstrates that this method achieves power balancing control within one output cycle. Finally, simulations and experiments verify the correctness and feasibility of the proposed control method.

This study addresses the power imbalance issue among cascaded units in cascaded H-bridge (CHB) inverters employing traditional phase disposition (PD) modulation. A novel modulation strategy based on vertical carrier adjustment is proposed. Taking a four-unit CHB inverter as an example, the strategy first optimizes traditional PD modulation by reducing the required number of triangular carriers. Subsequently, by vertically redistributing carriers across cascaded units, detailed analytical expressions for the duty cycles and average output power of each unit are derived over the full modulation index range, proving that the method achieves power balancing within one output cycle. Finally, simulations and experiments validate the effectiveness and feasibility of the proposed approach.

This paper investigates the T-type three-level topology. Based on quantitative analysis of voltage generation mechanism, the common mode (CM) reduction space vector modulation (CMRSVM) of T-type three-level inverter was studied. Based on virtual vector construction and regulation, an improved virtual space vector modulation (IVSVM) method was proposed in this paper, which can achieve the neutral-point (NP) voltage control and CM voltage suppression. In addition, the hybrid space vector modulation (HSVM) strategy combining CMRSVM and IVSVM provides an option for achieving comprehensive optimization of modulation performance. Finally, the experiments verified the correctness and feasibility of the proposed method.

Droop control is widely utilized in parallel inverter control within microgrids. However, conventional droop control strategy struggle to achieve reactive power sharing and circulating current suppression among multiple parallel inverters due to mismatched output impedances. To address this issue, this paper proposes a current-sharing strategy for single-phase parallel inverters based on multi-loop cooperative control. The proposed control strategy comprises a voltage-current loop, a droop control loop, a virtual impedance loop, and a reactive power tracking loop. Under the multi-loop cooperative control framework, the virtual impedance can be adaptively adjusted to compensate for output impedance discrepancies, thereby achieving reactive power balance and output current sharing in the parallel system. Finally, the effectiveness and feasibility of the control strategy were verified through experimental results.

As Dual Bridge Series Resonant Converter (DBSRC) are gaining increasing attention in power electronic transformers; multiple phase shift optimization methods have been widely studied. This paper proposes a 6-DOF (Degree of Freedom) multi-objective optimization method based on asymmetric phase shifting and frequency conversion control, which can optimize the resonant tank current to the minimum while maintaining the soft switching of all switches and achieving zero reactive power, thereby maximizing the transmission efficiency of DBSRC. Compared with traditional SPS control, MCT control and M-MCT control under current optimization, this method can not only achieve soft switching in the entire load range, but also has the minimum resonant tank current value. Finally, by building an experimental prototype, a comparative implementation under four control modes was carried out, verifying the superiority of the proposed control method in terms of resonant current, soft switching range, and efficiency.

Taking the T-type three-level inverter as an example, this paper first analyzes the mechanisms behind the generation of common-mode (CM) voltage and neutral-point (NP) voltage in T-type three-level inverters. Next, it examines the CMR-VSVPWM (Common-mode Reduced Virtual Space Vector PWM) method, which can control NP voltage balance and suppress CM voltage based on SVPWM. To reduce the switching losses of CMR-VSVPWM while maintaining cons-istent fundamental voltage amplitude, the paper proposes the Space Vector DPWMA and a hybrid modulation strategy, HPWM. This strategy determines whether to switch the modulation strategy in the next switching cycle based on the NP voltage and the charge flowing through the neutral point. This enables control of NP voltage and suppression of CM voltage across the entire modulation index. Finally, the correctness and feasibility of the proposed modulation strategies are validated through simulations.

The Dual Bridge Series Resonant Converter (DBSRC) under traditional single phase shift control is very easy to lose soft switching under light load and non-unit voltage gain, and has a large resonant current, which seriously affects the efficiency of the converter. To solve this problem, this paper proposes a 6-Degree-of-Freedom(6-DOF) global optimization control based on asymmetric phase shift, which can enable DBSRC to operate with zero return power and minimum resonant current while ensuring soft switching of all switching devices, thereby improving the efficiency of the converter. Finally, the feasibility and correctness of the proposed control strategy are verified by simulation, and the superiority of this control method in terms of resonant current and soft switching range is demonstrated by comprehensive comparison with SPS control, MCT control and M-MCT control.

In parallel inverter systems, traditional droop control often results in low power-sharing accuracy and significant circulating currents due to mismatched inverter output impedance. To improve power-sharing accuracy and minimize circulating currents, this paper proposes a control strategy for parallel inverters based on reactive power circular-chain adaptive virtual impedance. This strategy combines droop control with Circular Chain Control (3C) to create a circular-chain structure from the reactive power output of each parallel module. By constructing an adaptive virtual impedance that adjusts in real time according to reactive power requirements, this approach compensates for output impedance mismatches, achieving precise reactive power sharing. The effectiveness and feasibility of the proposed control strategy are validated through MATLAB simulations.

A zero input current ripple dc-dc converter is proposed which can be applied to two-stage system. A smaller capacitor of the auxiliary circuit that is introduced on the basis of flyback topology is responsible for dealing with the output power pulsation. Dual voltage loops are employed in the control system in order to keep both intermediate dc bus voltage and the voltage across the auxiliary capacitor stable. Indirect current control is adopted without current sampling. The low frequency input current ripple can be eliminated while the function of voltage conversion is achieved. In this paper, the operation principle of the circuit is analyzed in details. Besides, key design considerations and control strategy are also given. Finally, experimental results from a 75W prototype are presented to verify the advantages of the proposed converter.

本文针对现有"电力电子技术"相关教材中存在的对双向变换器的分析不完善和各知识点之间缺乏联系等问题,探析了双向Buck/Boost变换器的拓扑生成原理,并且详细分析了变换器运行于电感电流过零模式下实现零电压开关的具体过程,并推导出了软开关的实现条件.本文有助于学生理解并加深双向变换器与基本Buck和Boost变换器之间的联系和差别,并了解软开关技术在基本变换器中的应用,具有一定的教学指导意义.

级联H桥型逆变器因器件数量少、易于模块化、控制自由度高等优点,得到了普遍应用.但在传统多电平调制策略下,无法实现级联单元间功率均衡与逆变器输出线电压谐波特性最优的协调控制,输出功率不均衡或输出电压谐波特性较差时会直接影响逆变器输出电压波形质量.为此,该文以载波层叠调制技术为基础,提出一种基于1/2输出周期脉冲循环的功率均衡控制策略,揭示功率均衡条件下的载波分布普遍规律,并将其推广应用至n单元级联拓扑.所提策略在保证逆变器输出电压具有相对最优谐波特性的同时,能够实现单元间的功率均衡控制,消除了功率不均衡的不利影响.仿真和实验结果验证了所提控制策略的有效性.

针对级联H桥型逆变器,为兼顾级联单元间功率均衡和逆变器输出线电压谐波特性的控制,该文基于载波控制自由度,对各级联单元的输出进行重分配,提出基于1/4和1/2输出周期脉冲循环的功率均衡方案,所提方案能够在任意调制比和功率因数角下,控制级联单元在3/2个输出周期内实现功率均衡;为简化实现过程,对所提方案进行两次优化,使得载波数量和载波调整次数均大幅减少;同时,该文比较分析了原始功率均衡方案和优化功率均衡方案的异同点,结果表明基于1/2输出周期脉冲循环的二次优化方案获得了最佳的优化效果.最后,实验结果验证了理论分析的正确性和功率均衡方案的可行性.

Gestational diabetes mellitus is a progressive and complex pregnancy complication, which threatens both maternal and fetal health. It is urgent to screen for specific biomarkers for early diagnosis and precise treatment, as well as to identify key moleculars to better understand the pathogenic mechanisms. In the present review, we comprehensively summarized recent studies of gestational diabetes using mass spectrometry-based proteomic technologies. Focused on the entire experimental design and proteomic results, we showed that these studies have covered a broad range of research contents in terms of sampling time, sample types, and outcome associations. Although most of the studies only stayed in the stage of initial discovery, several proteins were further verified to be efficient for disease diagnosis. Functional analysis of all the combined significant proteins also showed that a small number of proteins are known to be involved in the regulation of insulin or indirect signaling pathways. However, many factors such as diagnostic criteria, sample processing, proteomic method, and statistical method can greatly affect the identification of reproducible and reliable protein candidates. Thus, we further provided constructive suggestions and recommendations for carrying out proteomic or follow-up studies of gestational diabetes or other pregnancy complications in the future.

对于级联H桥型逆变器,传统载波同相层叠调制策略和载波移相调制策略均无法使逆变器既具有最优线电压谐波特性,又能够实现级联单元间的功率均衡.为此,提出一种载波周期脉冲调整的功率均衡方法,此方法基于载波控制自由度,以载波周期为单位对传统载波排列进行调整;阐明了三单元载波分布的特征规律,仅需满足在第二层各级联单元载波均匀分布,即可以较少的载波数量在单位输出周期内实现级联单元间的功率均衡,且逆变器具有与传统载波同相层叠调制策略相同的线电压谐波特性.与此同时,详细推导了任意调制比和功率因数角下的级联单元输出特性,表明所提功率均衡方法的功率均衡效果不受调制比与功率因数角影响.仿真与实验结果验证了理论分析的正确性和功率均衡控制方法的可行性.

Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder occurred in pregnant women, and the mechanism for such disease is still unclear. The bioinformatics analysis of our previous study has revealed the abnormal expression of endoplasmic reticulum protein 29 (ERp29) in placental tissue of ICP patients. In this study, the function of ERp29 was further explored using in vitro model of ICP. The results showed that up-regulation of ERp29 occurred in TCA (taurocholic acid)-treated human trophoblast HTR-8/SVeno cells, and ERp29 inhibition reversed TCA toxicity via attenuating G2/M arrest and cell apoptosis. Mechanical study revealed ERp29 inhibition suppressed phosphorylation and kinase activity of p38, thus subsequently affecting expression and phosphorylation of p53 (ser18) as well as the transcriptional activity of p53. The conduction of this study might confirm the important role of ERp29 in ICP and which would be helpful for the development of target therapeutic method for ICP.

提出了一种基于离散一致性算法的多微电网互联运行分布式分层控制策略,初级控制确保单个直流微电网母线电压平衡;二级电压二次控制消除初级控制引入的电压偏差;三级功率流控制均衡直流微电网群的负载功率使得直流微电网能源、器件应力及寿命得到充分利用.所提控制策略中,各直流微电网只需与其邻接的单元通信获得全局信息实现互联稳定运行,通信压力降低.最后,搭建实验平台验证所提方法的有效性.

Phase disposition (PD) modulation method,compared with carrier phase shift (CPS),is better in terms of harmonic performance of line-line voltage for cascaded H-bridge multilevel inverter,but it results in power imbalance among cascaded cells.In order to solve this problem,this paper proposed a novel power balance strategy with PD modulation method.Firstly,the traditional PD modulation method was modified based on the modulation wave control degree of freedom,which can effectively reduce the number of carriers and roughly balance the active power of different cells.And then the cartier control degree of freedom was taken into consideration.By adjusting the arrangement of the cartier in the vertical direction,the secondary adjustment of every cell's output voltage is realized without changing the output voltage characteristic of the inverter and the power balance is achieved in one output cycle.This paper,taking three cells cascaded multilevel inverter as the example,gave the definition of power balance and the mechanism of power imbalance in traditional PD modulation and analyzed the principle of the proposed modulation method.Simulation and experimental results verified the validity of the proposed strategy.

Under the level-shifted pulse width modulation (LS-PWM) strategy, the expected output voltage of the cascaded H-bridge (CHB) inverter is superimposed by a variety of basic voltage waveforms, and the output power of every cell may be different with the different basic voltage waveforms. Therefore, to achieve the power balance among the cascaded cells, the output voltage of every cascaded cell must include all the basic voltage waveforms which have different output power in a certain time. In order to achieve this goal, a power balance control method and its optimization method based on carrier rotation in 1/4 output period were proposed in this paper, which combine the redundancy characteristics of the synthesis methods for the inverter's output levels and LS-PWM strategy control degree of freedom. The proposed power balance control method can realize the power balance among the cascaded cells in the shortest time without changing the harmonic characteristics of the output voltage of the inverter. Three cells cascaded multilevel inverter was taking as the example in this paper for the theoretical analysis, and simulation and experimental results were given to verify the correctness of the theoretical analysis.