Power Control Strategies for Single-Phase Voltage-Controlled Inverters with an Enhanced PLL

Jiayuan Gao,Jin-Bin Zhao,Chaojie He,Shuaitao Zhang,Fen Li 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

For maintaining a reliable and secure power system, this paper describes the design and implement of a single-phase grid-connected inverter with an enhanced phase-locked loop (PLL) and excellent power control performance. For designing the enhanced PLL and power regulator, a full-bridge voltage-controlled inverter (VCI) is investigated. When the grid frequency deviates from its reference values, the output frequency of the VCI is unstable with an oscillation of 2 doubling harmonics. The reason for this oscillation is analyzed mathematically. This oscillation leads to an injection of harmonics into the grid and even causes an output active power oscillation of the VCI. For eliminating the oscillation caused by a PLL, an oscillation compensation method is proposed. With the proposed method, the VCI maintains the original PLL control characteristics and improves the PLL robustness under grid frequency deviations. On the basis of the above analysis, a power regulator with the primary frequency and voltage modulation characteristics is analyzed and designed. Meanwhile, a small-signal model of the power loops is established to determine the control parameters. The VCI can accurately output target power and has primary frequency and voltage modulation characteristics that can provide active and reactive power compensation to the grid. Finally, simulation and experimental results are given to verify the idea.

Power Control Strategies for Single-Phase Voltage-Controlled Inverters with an Enhanced PLL

Gao, Jiayuan,Zhao, Jinbin,He, Chaojie,Zhang, Shuaitao,Li, Fen The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

For maintaining a reliable and secure power system, this paper describes the design and implement of a single-phase grid-connected inverter with an enhanced phase-locked loop (PLL) and excellent power control performance. For designing the enhanced PLL and power regulator, a full-bridge voltage-controlled inverter (VCI) is investigated. When the grid frequency deviates from its reference values, the output frequency of the VCI is unstable with an oscillation of 2 doubling harmonics. The reason for this oscillation is analyzed mathematically. This oscillation leads to an injection of harmonics into the grid and even causes an output active power oscillation of the VCI. For eliminating the oscillation caused by a PLL, an oscillation compensation method is proposed. With the proposed method, the VCI maintains the original PLL control characteristics and improves the PLL robustness under grid frequency deviations. On the basis of the above analysis, a power regulator with the primary frequency and voltage modulation characteristics is analyzed and designed. Meanwhile, a small-signal model of the power loops is established to determine the control parameters. The VCI can accurately output target power and has primary frequency and voltage modulation characteristics that can provide active and reactive power compensation to the grid. Finally, simulation and experimental results are given to verify the idea.

Study on Determination of Seven Transition Metal Ions in Water and Food by Microcolumn High-Performance Liquid Chromatography

Hu, Qiufen,Yang, Guangyu,Li, Haitao,Tai, Xi,Yin, Jiayuan Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5

A new method for the simultaneous determination of seven transition metal ions in water and food by microcolumn high-performance liquid chromatography has been developed. The lead, cadmium, mercury, nickel, cobalt, silver and tin ions were pre-column derivatized with tetra-(4-aminophenyl)-porphyrin ($T_4$-APP) to form the colored chelates which were then enriched by solid phase extraction with $C_{18}$ cartridge. The enrichment factor of 50 was achieved by eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The chelates were separated on a ZORBAX Stable Bound microcolumn ($2.0{\times}50\;mm,\;1.8\;{\mu}m$)with methanol-tetrahydrofuran (95 : 5, v/v, containing 0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0) as mobile phase at a flow rate of 0.5 mL/min and detected with a photodiode array detector from 350-600 nm. The seven chelates were separated completely within 2.0 min. The detection limits of lead, cadmium, mercury, nickel, cobalt, silver and tin are 4 ng/L, 3 ng/L, 6 ng/L, 5 ng/L, 5 ng/L, 6 ng/L, 4 ng/L respectively in the original samples. This method was applied to the determination of the seven transition metal in water and food samples with good results.

Circular RNA ROCK1, a novel circRNA, suppresses osteosarcoma proliferation and migration via altering the miR-532-5p/PTEN axis

Liu Yize,Qiu Guanzhen,Luo Yinzhou,Li Shanshan,Xu Yeqiu,Zhang Yuanzhuang,Hu Jiayuan,Li Peifeng,Pan Hai,Wang Yong 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

As the most prevalent bone tumor in children and adolescents, the pathogenesis and metastasis of osteosarcoma (OS) remain largely unclear. Here, we investigated the expression and function of a novel circular RNA (circRNA), circROCK1-E3/E4, which is back-spliced from exons 3 and 4 of Rho-associated coiled-coil containing protein kinase 1 (ROCK1) in OS. We found that circROCK1-E3/E4, regulated by the well-known RNA-binding protein quaking (QKI), was downregulated in OS and correlated with unfavorable clinical features of patients with OS. Functional proliferation and cell motility assays indicated that circROCK1-E3/E4 serves as a tumor suppressor in OS cells. Mechanistically, circROCK1-E3/E4 suppressed proliferation and migration by upregulating phosphatase and tensin homolog (PTEN) through microRNA-532-5p (miR-532-5p) sponging. In the constructed nude mouse model, circROCK1-E3/E4 inhibited tumor growth and lung metastasis in vivo. This study demonstrates the functions and molecular mechanisms of circROCK1-E3/E4 in the progression of OS. These findings may identify novel targets for the molecular therapy of OS.

Study on Determination of Seven Transition Metal Ions in Water and Food by Microcolumn High-Performance Liquid Chromatography

Qiufen Hu,Guangyu Yang*,Haitao Li,Xi Tai,Jiayuan Yin 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.5

Prevalence and Prognostic Role of PIK3CA/AKT1 Mutations in Chinese Breast Cancer Patients

Ling Deng,Xuehua Zhu,Yun Sun,Jiemin Wang,Xiaorong Zhong,Jiayuan Li,Min Hu,Hong Zheng 대한암학회 2019 Cancer Research and Treatment Vol.51 No.1

Purpose The prevalence of PIK3CA in Chinese breast cancer patients may be underestimated. Therefore, we investigated the distribution of somatic PIK3CA/AKT1mutations in Chinese breast cancer patients and explored their roles in tumor phenotypes and disease prognosis. Materials and Methods Tumors from 507 breast cancer patients were prospectively collected from the West China Hospital between 2008 and 2013. Whole exons of AKT1 and PIK3CAwere detected in freshfrozen tumors using next-generation sequencing, and correlations between PIK3CA/AKT1 mutations and clinicopathological features were analyzed. Results The AKT1mutation was found in 3.6% (18/507) of patients. Tumors from patients that carried the AKT1mutation were estrogen receptor (ER)+/progesterone receptor (PR)+/human epidermal growth factor receptor 2 (HER2) and were more likely to have high expression levels of Ki67. The prevalence of the PIK3CA mutation was 46.5% (236/507), and 35 patients carried two or three variants of the PIK3CA gene. PIK3CA mutations were associated with ER+/PR+/HER2 status. The prognosis of patients with one mutation in PIK3CA (or PIK3CA/AKT1) was not significantly different than that of patients with wild-type PIK3CA (or PIK3CA/AKT1), while patients with two or three variants in PIK3CA (or PIK3CA/AKT1) exhibited poorer outcomes in the entire group and in all three subgroups (ER+, HER2, Ki67 high), particularly with respect to overall survival. Conclusion A high frequency of somatic PIK3CA mutations was detected in Chinese breast cancer patients. In addition to the mutation frequency, the tumor mutational burden of the PIK3CA and AKT1 genes should also be of concern, as they may be associated with poor prognosis.