Finite control set model predictive control integrated with disturbance observer for battery energy storage power conversion system

Gao, Ning,Zhang, Bingtao,Wu, Weimin,Blaabjerg, Frede The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2

A typical battery energy storage system consists of a combination of battery packs and a grid-tied power conversion system. The control algorithm of the power conversion system plays an important role when interfacing the DC energy stored in battery packs with the conventional AC grid to generate an obedient bidirectional power flow. Finite control set model predictive control is believed to be one of the most effective choices for controlling power conversion systems. However, the performance of such a control strategy heavily depends on the accuracy of the predictive model. Parameter mismatch in the model leads to prediction error, which deteriorates the overall power quality performance of the power conversion system. Therefore, this paper studies a robust finite control set model predictive control method based on a discrete disturbance observer to eliminate the negative effects caused by model inaccuracy and uncertainty. The stability issue of the additional observer is discussed from the perspective of closed-loop poles. Parameter scan is performed to provide assistance in designing the feedback matrix. Finally, simulations and experimental results obtained from a downscaled prototype rated at 4.2 kVA are conducted as a validation of the presented control algorithm.

Crystallization behavior of MgO-Al2O3-SiO2 glassceramics prepared by directly heat-treating of laterite ore smelting slag

Ning Gao,Yaxu Chen,Chengyu Wang,Yanling Guo,Jieyu Zhang 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.6

In this paper, we proposed a novel method to prepare MgO-Al2O3-SiO2 (MAS) glass-ceramics through direct heat treatmentwith the slag of laterite ore. First, the Ni-Fe alloy and slag glass were prepared simultaneously by this method, and the yieldrate of Ni-Fe alloy was up to 95.69%. Then, the MAS glass-ceramics can be obtained by direct heat-treating for the slag glass. The energy consumption of glass-ceramics production was much lower than that in traditional method to make full use of thethermal energy of the molten slag. The crystallization behavior of the glass-ceramics was investigated by XRD, DSC andFESEM. The results demonstrate that many phase-separated droplets appear in the slag glass. During the heat treatment, thephase-separated droplets as favorable nucleation sites to inducing crystallization. The crystallinity and crystallite size of thesamples exhibits an increasing tendency with the increase of heat treatment temperature and time. The crystalline phases ofglass-ceramics were two different compositions magnesium aluminum silicates (MgAl2Si4O12 and (Mg,Al)SiO3). The activationenergies of the slag glass were calculated by Kissinger and Ozawa method, which were 308.81 and 309.36 kJ·mol-1, respectively. And the crystallization mechanism of the glass-ceramics was dominated by both the surface crystallization and bulkcrystallization with one-dimensional growth.

Active Disturbance Rejection Control Based on Extended State Observer for Three-Phase Battery Energy Storage Power Conversion System with LCL Filter

Gao Ning,Lin Xin,Lu Song,Xia Yue,Wu Weimin 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

Utilizing battery energy storage system is considered to be a reliable approach to improve the stability of modern power grid. By properly controlling the battery energy storage system, the redundant power can be absorbed and the lack of power can be supplemented. The control strategy of power conversion system directly aff ects the performance of battery energy storage system. Therefore, an improved active disturbance rejection control algorithm for power conversion system with LCL fi lter is presented in this paper. First of all, a pole placement strategy based on full state feedback is implemented in order to solve the resonance problem of LCL fi lter. Secondly, the total internal and external disturbances of power conversion system are compensated on basis of a linear extended state observer for purpose of improving the system robustness against inevitable interferences and parameter uncertainty. Furthermore, the stability of presented control strategy is analyzed and discussed in detail. Finally, the simulation and experimental results extracted based on a 2.6 kVA prototype are both provided, which can confi rm the feasibility and correctness of the control strategy.

Synthesis, Crystal Structure and Quantum Chemistry of a Novel Schiff Base N-(2,4-Dinitro-phenyl)-N'-(1-phenyl-ethylidene)-hydrazine

Ning-Ning Ji,Zhi-Qiang Shi,Ren-Gao Zhao,Ze-Bao Zheng,Zhi-Feng Li 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.4

A novel Schiff base N-(2,4-dinitro-phenyl)-N'-(1-phenyl-ethylidene)-hydrazine has been synthesized and structurally characterized by X-ray single crystal diffraction, elemental analysis, IR spectra and UV-vis spectrum. The crystal belongs to monoclinic with space group P21/n. The molecules are connected via intermolecular O-H···O hydrogen bonds into 1D infinite chains. The crystal structure is consolidated by the intramolecular N-H···O hydrogen bonds. weak intermolecular C-H···O hydrogen bonds link the molecules into intriguing 3D framework. Furthermore, Density functional theory (DFT) calculations of the structure, stabilities, orbital energies, composition characteristics of some frontier molecular orbitals and Mulliken charge distributions of the title compound were performed by means of Gaussian 03W package and taking B3LYP/6-31G(d) basis set. The time-dependent DFT calculations have been employed to calculate the electronic spectrum of the title compound, and the UV-vis spectra has been discussed on this basis. The results show that DFT method at B3LYP/6-31G(d) level can well reproduce the structure of the title compound.

Decitabine in the Treatment of Acute Myeloid Leukemia and Myelodysplastic Syndromes, Which Combined with Complex Karyotype Respectively

Gao, Su,Li, Zheng,Fu, Jian-Hong,Hu, Xiao-Hui,Xu, Yang,Jin, Zheng-Ming,Tang, Xiao-Wen,Han, Yue,Chen, Su-Ning,Sun, Ai-Ning,Wu, De-Pei,Qiu, Hui-Ying Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: We conducted a study exploring the clinical safety and efficacy of decitabine in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), combined with a complex karyotype. Materials and Methods: From April 2009 to September 2013, a total of 35 patients with AML/MDS combined with a complex karyotype diagnosed in the First Affiliated Hospital of Soochow University were included for retrospective analysis. All patients were treated with decitabine alone ($20mg/m^2$ daily for 5 days) or combination AAG chemotherapy (Acla 20mg qod*4d, Ara-C $10mg/m^2$ q12h*7d, G-CSF $300{\mu}g$ qd, the dose of G-CSF adjusted to the amount in blood routinely). Results: In 35 patients, 15 exhibited a complete response (CR), and 6 a partial response (PR), the overall response rate (CR+PR) being 60% (21 of 35). Median disease-free survival was 18 months and overall survival was 14 months. In the 15 MDS patients with a complex karyotype, the CR rate was 53.3% (8 of 15); in 20 AML patients with complex karyotype, the overall response rate was 65% (13 of 20). The response rate of decitabine alone (22 cases) was 56.5% (13 of 22), while in the combination chemotherapy group (13 cases), the effective rate was 61.5% (8 of 13)(P>0.05). There are 15 patients with chromosome 7 aberration, after treatment with decitabine, 7 CR, 3 PR, overall response rate was 66.7% (10 of 15). Of 18 patients with 3 to 5 kinds of chromosomal abnormalities, 66.7% demonstrated a response; of 17 with more than 5 chromosomal abnormalities, 52.9% had a response. In the total of 35 patients, with one course (23 patients) and ${\geq}$two courses (12 patients), the overall response rate was 40.9% and 92.3% (P<0.05). Grade III to IV hematological toxicity was observed in 27 cases (75%). Grade III to IV infections were clinically documented in 7 (20%). Grades I to II non-hematological toxicity were infections (18 patients), haematuria (2 patients), and bleeding (3 patients). With follow-up until September 2013, 7 patients were surviving, 18 had died and 10 were lost to follow-up. In the 6 cases who underwent allogeneic hematopoietic stem cell transplantation (HSCT) all were still relapse-free survivors. Conclusions: Decitabine alone or combination with AAG can improve outcome of AML/MDS with a complex karyotype, there being no significant difference decitabine in inducing remission rates in patients with different karyotype. Increasing the number of courses can improve efficiency. This approach with fewer treatment side effects in patients with a better tolerance should be employed in order to create an improved subsequent chance for HSCT.

An Improved Control Method for Power Conversion System under a Weak Grid by the Adoption of Virtual Resistors

Gao, Ning,Sang, Shun,Li, Rui,Cai, Xu The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3

The control of the power conversion system (PCS) in a battery energy storage system has a challenge due to the existence of grid impedance. This paper studies an impedance model of an LCL-based PCS in the d-q domain. The feature of a PCS connected to a weak grid is unveiled by use of an impedance model and a generalized Nyquist criterion. It is shown that the interaction between grid impedance and the PCS destabilizes the cascaded system in certain cases. Therefore, this paper proposes a novel control method that adopts virtual resistors to overcome this issue. The improvement in the control loop leads the PCS to a more stable condition than the conventional method. Impedance measurement is implemented to verify the correctness of the theoretical analysis. Experimental results obtained from a down-scaled prototype indicate that the proposed control method can improve the performance of the PCS under a weak grid.

Famine exposure in early life and type 2 diabetes in adulthood: findings from prospective studies in China

Ning Feng,Zhao Jing,Zhang Lei,Wang Weijing,Sun Xiaohui,Song Xin,Zhang Yanlei,Xin Hualei,Gao Weiguo,Gao Ruqin,Zhang Dongfeng,Pang Zengchang 한국영양학회 2023 Nutrition Research and Practice Vol.17 No.4

BACKGROUND/OBJECTIVES: This study examined the relationship between famine exposure in early life and the risk of type 2 diabetes in adulthood during the 1959–1961 Chinese Famine. SUBJECTS/METHODS: A total of 3,418 individuals aged 35–74 years free of diabetes from two studies in 2006 and 2009 were followed up prospectively in 2009 and 2012, respectively. Famine exposure was classified as unexposed (individuals born in 1962–1978), fetal exposed (individuals born in 1959–1961), child exposed (individuals born in 1949–1958), and adolescent/adult exposed (born in 1931–1948). A logistic regression model was used to assess the relationship between famine exposure and diabetes after adjustment for potential covariates. RESULTS: During a three-year follow-up, the age-adjusted incidence rates of type 2 diabetes were 5.7%, 14.5%, 12.7%, and 17.8% in unexposed, fetal-exposed, child-exposed, and adolescent/adult-exposed groups, respectively (P < 0.01). Relative to the unexposed group, the relative risks (95% confidence inter val) for diabetes were 2.15 (1.29–3.60), 1.53 (0.93– 2.51), and 1.65 (0.75–3.63) in the fetal-exposed, child-exposed, and adolescent/adult-exposed groups, after controlling for potential covariates. The interactions between famine exposure and obesity, education level, and family histor y of diabetes were not obser ved, except for the urbanization type. Individuals living in rural areas with fetal and childhood famine exposure were at a higher risk of type 2 diabetes, with relative risks of 8.79 (1.82–42.54) and 2.33 (1.17–4.65), respectively. CONCLUSIONS: These findings indicate that famine exposure in early life is an independent predictor of type 2 diabetes, particularly in women. Early identification and inter vention may help prevent diabetes in later life.

A New Fuzzy Key Generation Method Based on PHY-Layer Fingerprints in Mobile Cognitive Radio Networks

( Ning Gao ),( Xiaojun Jing ),( Songlin Sun ),( Junsheng Mu ),( Xiang Lu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.7

Classical key generation is complicated to update and key distribution generally requires fixed infrastructures. In order to eliminate these restrictions researchers have focused much attention on physical-layer (PHY-layer) based key generation methods. In this paper, we present a PHY-layer fingerprints based fuzzy key generation scheme, which works to prevent primary user emulation (PUE) attacks and spectrum sensing data falsification (SSDF) attacks, with multi-node collaborative defense strategies. We also propose two algorithms, the EA algorithm and the TA algorithm, to defend against eavesdropping attacks and tampering attacks in mobile cognitive radio networks (CRNs). We give security analyses of these algorithms in both the spatial and temporal domains, and prove the upper bound of the entropy loss in theory. We present a simulation result based on a MIMO-OFDM communication system which shows that the channel response characteristics received by legitimates tend to be consistent and phase characteristics are much more robust for key generation in mobile CRNs. In addition, NIST statistical tests show that the generated key in our proposed approach is secure and reliable.

Modified Inertia Synchronization Control for a Type-IV Wind Turbine Integrated with a Battery Energy Storage Unit

Gao Ning,Lin Xin,Sang Shun 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

Inertia synchronization control is a good solution for type-IV wind turbine to provide an inertia response to the grid. To further improve its frequency support performance, this paper addresses a battery energy storage unit on the DC link side of the full power back-to-back wind energy converter. After that, the corresponding modifi ed control strategy is implemented as an upgraded version of existing inertia synchronization control from the view of emulating the behavior of a traditional synchronous generator widely used in power system for decades. Moreover, a control method based on removable virtual resistors co-operated with reconfi guration of battery energy storage unit’s control structure is studied in detail to improve the low voltage ride through performance of the wind turbine. Simulation results are obtained based on the environment of PSCAD/EMTDC, which can certify the correctness and feasibility of the presented control method in this paper.

An Improved Control Method for Power Conversion System under a Weak Grid by the Adoption of Virtual Resistors

Ning Gao,Shun Sang,Rui Li,Xu Cai 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3

The control of the power conversion system (PCS) in a battery energy storage system has a challenge due to the existence of grid impedance. This paper studies an impedance model of an LCL-based PCS in the d-q domain. The feature of a PCS connected to a weak grid is unveiled by use of an impedance model and a generalized Nyquist criterion. It is shown that the interaction between grid impedance and the PCS destabilizes the cascaded system in certain cases. Therefore, this paper proposes a novel control method that adopts virtual resistors to overcome this issue. The improvement in the control loop leads the PCS to a more stable condition than the conventional method. Impedance measurement is implemented to verify the correctness of the theoretical analysis. Experimental results obtained from a down-scaled prototype indicate that the proposed control method can improve the performance of the PCS under a weak grid.