PQ Control of Micro Grid Inverters with Axial Voltage Regulators

Chen, Yang,Zhao, Jinbin,Qu, Keqing,Li, Fen The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a PQ control strategy for micro grid inverters with axial voltage regulators. The inverter works in the voltage-controlled mode and can help improve the terminal power quality. The inverter has two axial voltage regulators. The 1st regulator involves the output voltage amplitude and output impedance, while the 2nd regulator controls the output frequency. The inverter system is equivalent to a controllable voltage source with a controllable inner output impedance. The basic PQ control for micro grid inverters is easy to accomplish. The output active and reactive powers can be decoupled well by controlling the two axial voltages. The 1st axial voltage regulator controls the reactive power, while the 2nd regulator controls the active power. The paper analyses the axial voltage regulation mechanism, and evaluates the PQ decoupling effect mathematically. The effectiveness of the proposed control strategy is validated by simulation and experimental results.

PQ Control of Micro Grid Inverters with Axial Voltage Regulators

Yang Chen,Jinbin Zhao,Keqing Qu,Fen Li 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a PQ control strategy for micro grid inverters with axial voltage regulators. The inverter works in the voltage-controlled mode and can help improve the terminal power quality. The inverter has two axial voltage regulators. The 1st regulator involves the output voltage amplitude and output impedance, while the 2nd regulator controls the output frequency. The inverter system is equivalent to a controllable voltage source with a controllable inner output impedance. The basic PQ control for micro grid inverters is easy to accomplish. The output active and reactive powers can be decoupled well by controlling the two axial voltages. The 1st axial voltage regulator controls the reactive power, while the 2nd regulator controls the active power. The paper analyses the axial voltage regulation mechanism, and evaluates the PQ decoupling effect mathematically. The effectiveness of the proposed control strategy is validated by simulation and experimental results.

A Decupled PQ Control strategy of Voltage - Controlled Inverters

Yang Chen,Jinbin Zhao,Jinlong Wang,Keqing Qu,Shuuichi Ushiki,Masaaki Ohshima 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper deals with problems caused by high distributed generation penetration and proposes a simple and precise PQ control strategy for voltage-controlled inverters in micro grids. The widely-used current-controlled inverters cannot provide voltage support for micro grids and have to develop seamless transfer strategy between gird connected mode and islanded mode. A voltage-controlled inverter is raised in the paper due to the problems. The new inverter can be regarded as a voltage source cascaded with controllable output impedance. By adopting a new phase-locked loop, the output voltage amplitude and frequency are well decoupled. Thus output active and reactive powers are decoupled satisfactory. The output response is fast and precise. The idea is verified by simulation and experiment results.

Prediction of Pathologic Response to Neoadjuvant Chemoradiotherapy in Patients with Esophageal Squamous Cell Carcinoma Incorporating Hematological Biomarkers

Yingjia Wu,Jinbin Chen,Lei Zhao,Qiaoqiao Li,Jinhan Zhu,Hong Yang,Suping Guo,Mian Xi 대한암학회 2021 Cancer Research and Treatment Vol.53 No.1

Purpose This study aimed to develop a nomogram for predicting pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma (ESCC) by integrating hematological biomarkers and clinicopathological characteristics. Materials and Methods Between 2003 and 2017, 306 ESCC patients who underwent neoadjuvant CRT followed by esophagectomy were analyzed. Besides clinicopathological factors, hematological parameters before, during, and after CRT were collected. Univariate and multivariate logistic regression analyses were performed to identify predictive factors for pCR. A nomogram model was built and internally validated. Results Absolute lymphocyte count (ALC), lymphocyte to monocyte ratio, albumin, hemoglobin, white blood cell, neutrophil, and platelet count generally declined, whereas neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) increased significantly following neoadjuvant CRT. After surgery, 124 patients (40.5%) achieved a pCR. The pCR group demonstrated significantly more favorable survival than the non-pCR group. On multivariate analysis, significant factors associated with pCR included sex, chemotherapy regimen, post-CRT endoscopic finding, pre-CRT NLR, ALC nadir during CRT, and post-CRT PLR, which were incorporated into the prediction model. The nomogram indicated good accuracy in predicting pCR, with a C-index of 0.75 (95% confidence interval, 0.71 to 0.78). Conclusion Female, chemotherapy regimen of cisplatin/vinorelbine, negative post-CRT endoscopic finding, pre-CRT NLR (≤ 2.1), ALC nadir during CRT (> 0.35×109/L), and post-CRT PLR (≤ 83.0) were significantly associated with pCR in ESCC patients treated with neoadjuvant CRT. A nomogram incorporating hematological biomarkers to predict pCR was developed and internally validated, showing good predictive performance.

Grid-friendly Characteristics Analysis and Implementation of a Single-phase Voltage-controlled Inverter

Shuaitao Zhang,Jinbin Zhao,Yang Chen,Chaojie He 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

Inverters are widely used in distributed power generation and other applications. However, their lack of inertia and variable impedance may cause system instability and power transfer inaccuracy. This paper proposes a control scheme for a single phase voltage-controlled inverter with some grid-friendly characteristics. The proposed control algorithm enables the inverter to function as a voltage source with an inner output impedance in both the islanded and grid-connected modes. Virtual inertia and rotor equations are embedded in the PLL part. Thus, the frequency stability can remain. The inner output impedance can be adjusted freely, which helps to accurately decouple and transmit the output active and reactive power. The proposed inverter operates like a traditional synchronous generator. Simulations and experiments are designed and carried out to verify the proposed control strategy.

Optimal Consensus Control for Heterogeneous Nonlinear Multiagent Systems with Partially Unknown Dynamics

Tao Wang,Hao Fu,Jinbin Li,Yaodong Zhang,Xinfeng Zhou,Xin Chen 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.9

This paper focuses on an optimal consensus problem for heterogeneous discrete-time nonlinear multiagent systems (MASs) with partially unknown dynamics. For those systems, it is difficult to obtain the solution of the coupled Hamilton-Jacobi-Bellman (HJB) equations, which is necessary to address the optimal consensus problem. A new hierarchical and distributed optimal control strategy is developed to derive the near solution of the HJB equations. Its control structure consists of the model reference adaptive control (MRAC) layer and distributed control layer. In the MRAC layer, the adaptive feedforward and feedback controller is designed to make the states of followers converge to ones of their corresponding reference models. Then, the optimal consensus problem of heterogeneous MASs is formulated as that of homogeneous MASs. In the distributed control layer, an online distributed value iteration algorithm is proposed to approximate the optimal solution of the HJB equations for reference models. Thereby, the optimal consensus is also achieved for the heterogeneous MASs. The two convergence properties are analyzed to demonstrate the MRAC performance and the optimal consensus, respectively. Simulation results verify the effectiveness of the proposed strategy.

Grid-friendly Characteristics Analysis and Implementation of a Single-phase Voltage-controlled Inverter

Zhang, Shuaitao,Zhao, Jinbin,Chen, Yang,He, Chaojie The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.5

Inverters are widely used in distributed power generation and other applications. However, their lack of inertia and variable impedance may cause system instability and power transfer inaccuracy. This paper proposes a control scheme for a single phase voltage-controlled inverter with some grid-friendly characteristics. The proposed control algorithm enables the inverter to function as a voltage source with an inner output impedance in both the islanded and grid-connected modes. Virtual inertia and rotor equations are embedded in the PLL part. Thus, the frequency stability can remain. The inner output impedance can be adjusted freely, which helps to accurately decouple and transmit the output active and reactive power. The proposed inverter operates like a traditional synchronous generator. Simulations and experiments are designed and carried out to verify the proposed control strategy.

Evaluating optimum tilt angle for PV modules using solar radiation models in Wuhan, China

Fen. Li,Nianjun. Ma,Jinbin. Zhao,Keqing. Qu,Xingwu. Yang,Zhenghong. Chen 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Four models are used to estimate the hourly solar radiation on 15 pieces of different tilted photovoltaic (PV) modules in Wuhan, China based on power and solar radiation data during a whole year. The optimum tilt angle (OTA) in Wuhan for yearly and semi-yearly adjustment was determined. Then it was determined that the best mode is the tilt angle of PV module adjusted every half a year. In semi-yearly adjustment, OTA in semi-year of winter and summer is found as 45°, 15°, respectively. Experimental results verify the theoretical calculated values of the OTA with high precision. Energy radio (ER) reveals PV modules with adjustment of tilt angle twice a year has a capability to improve nearly 7% in comparison with fixed type. The best model was chosen based on test results from statistical indicators. The statistical results demonstrate that among the studied models, Liu&Jordan model is the most accurate.

Ginseng berry polysaccharides on infl ammation-associated colon cancer: inhibiting T-cell differentiation, promoting apoptosis, and enhancing the effects of 5-fl uorouracil

Chong-Zhi Wang,Lifei Hou,Jin-Yi Wan,Haiqiang Yao,Jinbin Yuan,Jinxiang Zeng,Chan Woong Park,Su Hwan Kim,Dae Bang Seo,Kwang-Soon Shin,Chun-Feng Zhang,Lina Chen,Qi-Hui Zhang,Zhi Liu,Clara Sava-Segal,Chun 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.2

Background: Ginseng is a commonly used herbal medicine in treating various medical conditions. Chronic gut inflammation is a recognized factor for the development of colorectal cancer (CRC). In thisproject, Asian ginseng berry polysaccharide preparations were used to assess their effects on CRC andrelated immune regulation mechanisms. Methods: Ginseng berry polysaccharide extract (GBPE) and purified ginseng berry polysaccharideportion (GBPP) were used to evaluate their activities on human HCT-116 and HT-29 CRC cell proliferation. Interleukin-8 secretion analysis was performed on HT-29 cells. Naive CD4 cell isolation and T-helper celldifferentiation were performed and determined using flow cytometry for Th1 and Treg in addition to cellcycle and apoptotic investigation. Results: GBPE and GBPP significantly inhibited interleukin-8 secretion and cancer cell proliferation,inhibited CD4þIFN-gþ cell (Th1) differentiation, and decreased CD4þFoxP3þ cell (Treg) differentiation. Compared to the GBPE, GBPP showed more potent antiinflammatory activities on the malignant cells. This is consistent with the observation that GBPP can also inhibit Th1-cell differentiation better, suggestingthat it has an important role in antiinflammation, whereas Treg cells hinder the body’s immuneresponse against malignancies. Supported by cell cycle and apoptosis data, GBPE and GBPP, at variousdegrees, remarkably enhanced the anticancer activities of 5-fluorouracil. Conclusion: Data from this project suggested that Asian ginseng berry potentially has clinical utility inmanaging enteric inflammation and suppressing CRC through immunomodulation mechanisms.

Ginseng berry polysaccharides on inflammation-associated colon cancer: inhibiting T-cell differentiation, promoting apoptosis, and enhancing the effects of 5-fluorouracil

Wang, Chong-Zhi,Hou, Lifei,Wan, Jin-Yi,Yao, Haiqiang,Yuan, Jinbin,Zeng, Jinxiang,Park, Chan Woong,Kim, Su Hwan,Seo, Dae Bang,Shin, Kwang-Soon,Zhang, Chun-Feng,Chen, Lina,Zhang, Qi-Hui,Liu, Zhi,Sava-Se The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.2

Background: Ginseng is a commonly used herbal medicine in treating various medical conditions. Chronic gut inflammation is a recognized factor for the development of colorectal cancer (CRC). In this project, Asian ginseng berry polysaccharide preparations were used to assess their effects on CRC and related immune regulation mechanisms. Methods: Ginseng berry polysaccharide extract (GBPE) and purified ginseng berry polysaccharide portion (GBPP) were used to evaluate their activities on human HCT-116 and HT-29 CRC cell proliferation. Interleukin-8 secretion analysis was performed on HT-29 cells. Naive CD4 cell isolation and T-helper cell differentiation were performed and determined using flow cytometry for Th1 and Treg in addition to cell cycle and apoptotic investigation. Results: GBPE and GBPP significantly inhibited interleukin-8 secretion and cancer cell proliferation, inhibited CD4⁺IFN-γ⁺ cell (Th1) differentiation, and decreased CD4⁺FoxP3⁺ cell (Treg) differentiation. Compared to the GBPE, GBPP showed more potent antiinflammatory activities on the malignant cells. This is consistent with the observation that GBPP can also inhibit Th1-cell differentiation better, suggesting that it has an important role in antiinflammation, whereas Treg cells hinder the body's immune response against malignancies. Supported by cell cycle and apoptosis data, GBPE and GBPP, at various degrees, remarkably enhanced the anticancer activities of 5-fluorouracil. Conclusion: Data from this project suggested that Asian ginseng berry potentially has clinical utility in managing enteric inflammation and suppressing CRC through immunomodulation mechanisms.