Disturbance observer based non‑singular fast terminal sliding mode control of permanent magnet synchronous motors

Junjie Jiang,Housheng Zhang,Duo Jin,Ao Wang,Longhao Liu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

The existence of load disturbance can lead to the instability of permanent magnet synchronous motor (PMSM) speed control systems. Therefore, a non-singular fast terminal sliding mode control (NFTSMC) strategy based on a disturbance observer is proposed in this paper. First, a new exponential reaching law is presented to relate the rate of convergence to the state error and switching function, which achieves an improvement of the system convergence speed while reducing system jitter. At the same time, to eliminate system jitter, a new smooth saturation function is introduced in place of the symbolic function. Second, a non-singular fast terminal (NFT) sliding surface is generated by combining a nonlinear function with a linear funtion, which makes the state error converge rapidly at different stages. Finally, a disturbance observer is built to boost the robustness of the control system by observing the outside disturbance value and feeding it back to the speed controller. The dependability and effectiveness of the proposed control strategy are confirmed by simulation experiments with MATLAB.

Efficacy and dosimetry analysis of image-guided radioactive 125I seed implantation as salvage treatment for pelvic recurrent cervical cancer after external beam radiotherapy

Ang Qu,Ping Jiang,Haitao Sun,Weijuan Jiang,Yuliang Jiang,Suqing Tian,Junjie Wang 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.1

Objective: To investigate the efficacy of image-guided radioactive 125I seed (IGRIS) implantation for pelvic recurrent cervical cancer (PRCC) after external beam radiotherapy (EBRT), and analyze the influence of clinical and dosimetric factors on efficacy. Methods: From July 2005 to October 2015, 36 patients with PRCC received IGRIS. We evaluated local progression-free survival (LPFS) and overall survival (OS). Results: The median follow up was 11.5 months. The 1- and 2-year LPFS rate was 34.9% and 20%, respectively. The multivariate analysis indicated recurrence site (central or pelvic wall) (hazard ratio [HR]=0.294; 95% confidence interval [CI]=0.121–0.718), lesion volume (HR=2.898; 95% CI=1.139–7.372), D 90 (HR=0.332; 95% CI=0.130–0.850) were the independent factors affecting LPFS. The 1- and 2-year OS rate was 52.0% and 19.6%, respectively. The multivariate analysis suggested pathological type (HR=9.713; 95% CI=2.136–44.176) and recurrence site (HR=0.358; 95% CI=0.136–0.940) were the independent factors affecting OS. The dosimetric parameters of 33 patients mainly included D 90 (128.5±47.4 Gy), D 100 (50.4±23.7 Gy) and V 100 (86.7%±12.9%). When D 90 ≥105 Gy or D 100 ≥55 Gy or V 100 ≥91%, LPFS was extended significantly, but no significant difference for OS. The 79.2% of 24 patients with local pain were suffering from pain downgraded after radioactive 125I seed implantation. Conclusion: IGRIS implantation could be a safe and effective salvage treatment for PRCC after EBRT, which could markedly release the pain. Recurrence site, tumor volume and dose were the main factors affected efficacy. Compared with central recurrence, it was more suitable for patients with pelvic wall recurrent cervical cancer after EBRT.

Active Voltage-balancing Control Methods for the Floating Capacitors and DC-link Capacitors of Five-level Active Neutral-Point-Clamped Converter

Junjie Li,Jianguo Jiang 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3

Multilevel active neutral-point-clamped (ANPC) converter combines the advantages of three-level ANPC converter and multilevel flying capacitor (FC) converter. However, multilevel ANPC converter often suffers from capacitor voltage balancing problems. In order to solve the capacitor voltage balancing problems for five-level ANPC converter, phase-shifted pulse width modulation (PS-PWM) is used, which generally provides natural voltage balancing ability. However, the natural voltage balancing ability depends on the load conditions and converter parameters. In order to eliminate voltage deviations under steady-state and dynamic conditions, the active voltage-balancing control (AVBC) methods of floating capacitors and dc-link capacitors based on PS-PWM are proposed. First, the neutral-point current is regulated to balance the neutral-point voltage by injecting zero-sequence voltage. After that, the duty cycles of the redundant switch combinations are adjusted to balance the floating-capacitor voltages by introducing moderating variables for each of the phases. Finally, the effectiveness of the proposed AVBC methods is verified by experimental results.

Deadbeat and Hierarchical Predictive Control with Space-Vector Modulation for Three-Phase Five-Level Nested Neutral Point Piloted Converters

Junjie Li,Xiangyu Chang,Dirui Yang,Yunlong Liu,Jianguo Jiang 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

To achieve a fast dynamic response and to solve the multi-objective control problems of the output currents, capacitor voltages and system constraints, this paper proposes a deadbeat and hierarchical predictive control with space-vector modulation (DB-HPC-SVM) for five-level nested neutral point piloted (NNPP) converters. First, deadbeat control (DBC) is adopted to track the reference currents by calculating the deadbeat reference voltage vector (DB-RVV). After that, all of the candidate switching sequences that synthesize the DB-RVV are obtained by using the fast SVM principle. Furthermore, according to the redundancies of the switch combination and switching sequence, a hierarchical model predictive control (MPC) is presented to select the optimal switch combination (OSC) and optimal switching sequence (OSS). The proposed DB-HPC-SVM maintains the advantages of DBC and SVM, such as fast dynamic response, zero steady-state error and fixed switching frequency, and combines the characteristics of MPC, such as multi-objective control and simple inclusion of constraints. Finally, comparative simulation and experimental results of a five-level NNPP converter verify the correctness of the proposed DB-HPC-SVM.

Active Voltage-balancing Control Methods for the Floating Capacitors and DC-link Capacitors of Five-level Active Neutral-Point-Clamped Converter

Li, Junjie,Jiang, Jianguo The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3

Multilevel active neutral-point-clamped (ANPC) converter combines the advantages of three-level ANPC converter and multilevel flying capacitor (FC) converter. However, multilevel ANPC converter often suffers from capacitor voltage balancing problems. In order to solve the capacitor voltage balancing problems for five-level ANPC converter, phase-shifted pulse width modulation (PS-PWM) is used, which generally provides natural voltage balancing ability. However, the natural voltage balancing ability depends on the load conditions and converter parameters. In order to eliminate voltage deviations under steady-state and dynamic conditions, the active voltage-balancing control (AVBC) methods of floating capacitors and dc-link capacitors based on PS-PWM are proposed. First, the neutral-point current is regulated to balance the neutral-point voltage by injecting zero-sequence voltage. After that, the duty cycles of the redundant switch combinations are adjusted to balance the floating-capacitor voltages by introducing moderating variables for each of the phases. Finally, the effectiveness of the proposed AVBC methods is verified by experimental results.

Efficient treatment of anthraquinone dye wastewater by adsorption using sunflower torus-like magnesium hydroxide microspheres

Demin Jiang,Fang Wang,Bo Lan,Dacai Wang,Kezhong Liang,Tingzhen Li,Dongfeng Zhao,Jianjun Chen,Junjie Lin,Wen Chan,Yuke Li 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.3

Novel sunflower torus-like magnesium hydroxide (MH) microsphere particles were prepared by a facile one-step, self-assembly method. The synthesized products and the mechanism of adsorption of samples of the anthraquinone dyes reactive blue 19 (RB19) and alizarin red S (ARS) were analyzed by different modern characterization techniques, such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectrometry (EDS), the Brunauer-Emmett-Teller (BET) method and Fourier transform infrared (FT-IR) spectroscopy. The adsorptive potential of the as-prepared microspheres for the removal of RB19 and ARS in aqueous solution was evaluated. The effects of multiple condition parameters, including, adsorbent dosage, adsorption time, adsorption temperature, wastewater pH, rotating speed and sodium chloride concentration on the removal of the dyes from the wastewater were studied in detail. The effect of the structural and shape properties of the MH adsorbent on the dye adsorption performances was also studied. The results showed that sunflower torus-like MH was an effective adsorbent for dye removal. The removal rates of ARS and RB19 were 91.65% and 83.03%, respectively, under the optimized conditions. The maximum adsorption capacity of the microspheres was 349.85mg/g for ARS and 231.78mg/g for RB19 at 25 oC. The equilibrium adsorption experimental data of the microsphere adsorption conformed to the Freundlich isotherm for ARS and the Langmuir isotherm for RB19. The adsorption kinetics experimental studies showed that the pseudo-second-order and pseudo-first-order model perfectly fit for both ARS and RB19 microsphere adsorption. RB19 and ARS were absorbed on the sunflower torus-like MH surface via the formation of H-bonds. Thus, the sunflower torus-like MH microsphere particles are an effective purifying agent for the removal of the anthraquinone dyes ARS and RB19 from wastewater.

Deadbeat and Hierarchical Predictive Control with Space-Vector Modulation for Three-Phase Five-Level Nested Neutral Point Piloted Converters

Li, Junjie,Chang, Xiangyu,Yang, Dirui,Liu, Yunlong,Jiang, Jianguo The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6

To achieve a fast dynamic response and to solve the multi-objective control problems of the output currents, capacitor voltages and system constraints, this paper proposes a deadbeat and hierarchical predictive control with space-vector modulation (DB-HPC-SVM) for five-level nested neutral point piloted (NNPP) converters. First, deadbeat control (DBC) is adopted to track the reference currents by calculating the deadbeat reference voltage vector (DB-RVV). After that, all of the candidate switching sequences that synthesize the DB-RVV are obtained by using the fast SVM principle. Furthermore, according to the redundancies of the switch combination and switching sequence, a hierarchical model predictive control (MPC) is presented to select the optimal switch combination (OSC) and optimal switching sequence (OSS). The proposed DB-HPC-SVM maintains the advantages of DBC and SVM, such as fast dynamic response, zero steady-state error and fixed switching frequency, and combines the characteristics of MPC, such as multi-objective control and simple inclusion of constraints. Finally, comparative simulation and experimental results of a five-level NNPP converter verify the correctness of the proposed DB-HPC-SVM.

Comparison of leaf transcriptomes of cassava “Xinxuan 048” diploid and autotetraploid plants

Ling Yin,Junjie Qu,Huiwen Zhou,Xiaohong Shang,Hui Fang,Jiang Lu,Huabing Yan 한국유전학회 2018 Genes & Genomics Vol.40 No.9

Polyploidy breeding of cassava has been used to improve cassava traits over the past years. We previously reported in vitro induction of tetraploids in the cassava variety “Xinxuan 048” using colchicine. Significant differences in morphology and anatomy were found between the diploid and tetraploid plants. However, very little is known about the transcriptome difference between them. In this study, morphological and physiological characteristics including leaf thickness, plant height, internode length, chlorophyll content, and photosynthetic capacity were measured. Further, we investigated and validated the difference in gene expression patterns between cassava “Xinxuan 048” tetraploid genotype and its diploid plants using RNA sequencing (RNAseq) and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Significant differences in morphology and physiology were observed during tetraploidization. A comparison revealed that tetraploidy induced very limited changes in the leaf transcriptomes of cassava “Xinxuan 048” diploid and autotetraploid plants. However, the differentially expressed genes (DEGs) between 2× and 4× plants, especially those upregulated in 4× plants, were strongly associated with hormonal and stress responses. Large changes in morphology and physiology between the diploid cassava “Xinxuan 048” and its autotetraploid were not associated with large changes in their leaf transcriptomes. Moreover, the differently expressed genes related to the regulation of gibberellin and brassinosteroids potentially explained why the plant height and internode length of 4× plants became shorter. Collectively, our results suggest that 4× cassava is potentially valuable for breeding strains with improved stress resistance.

Structural features and thermoelectric performance of chalcopyrite Cu(In, Ga)Te2 system by isoelectronic substitution

Deng Shuping,Jiang Xianyan,Zhang Ziye,Liu Junjie,Chen Lili,Qi Ning,Tang Xinfeng,Wu Yichu,Chen Zhiquan 한국물리학회 2021 Current Applied Physics Vol.26 No.-

In this paper, a series of CuIn1-xGaxTe2 samples were prepared by vacuum melting combined with the spark plasma sintering process based on the initial stoichiometric ratios of 1: 1-x: x: 2 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0). Crystal results indicate that all Cu(In, Ga)Te2 system samples are the chalcopyrite structure with space group I42d. Thermal analysis results show that all the samples have excellent reproducibility and thermal stability. EPMA data indicates that Ga tended to replace In site instead of Cu or Te. Meanwhile, the roomtemperature carrier concentration of all p-type samples varies from 0.30 × 1019 to 1.25 × 1019cm 3, since carrier mobility changes from 15.16 to 69.27 cm2 V 1 s 1. Ultimately, the significantly reduced total thermal conductivity is observed in the Ga-doped samples, and the maximum ZT value of 0.80 is obtained at 773 K for the CuIn0.8Ga0.2Te2 sample due to the lower thermal conductivity

Isoperistaltic side-to-side anastomosis for the surgical treatment of Crohn disease

Wenhao Chen,Junjie Zhou,Min Chen,Congqing Jiang,Qun Qian,Zhao Ding 대한외과학회 2022 Annals of Surgical Treatment and Research(ASRT) Vol.103 No.1

Purpose: Increasing evidence has shown an association of surgical technique, particularly anastomotic configuration, with postoperative recurrence of CD. This pilot study aimed to evaluate short-term outcomes of isoperistaltic side-to-side anastomosis (ISSA) employed on Crohn disease (CD) patients. Methods: Data were retrieved from a prospectively maintained database. Postoperatively, all patients were followed up with close endoscopic (ileocolonoscopy) surveillance. Results: From January 2017 to May 2021, 30 patients diagnosed with CD who underwent ISSA were compared with 45 CD patients who underwent antiperistaltic side-to-side anastomosis (ASSA). The 2 groups were comparable in baseline demographics and clinical characteristics. No significant differences were observed between groups regarding postoperative safety issues, including anastomotic leak, abdominal/pelvic abscess, length of hospital stay, readmission rate within 30 days, etc. At postoperative 24th month, reduced endoscopic recurrence was observed in the ISSA group compared with that in the ASSA group (18 of 24, 75.0%, . 36 of 38, 94.7%; P = 0.024). Regarding surgical recurrence, there was 0% in the ISSA group . 4.4% (2 of 45) in the ASSA group (P = 0.510). Conclusion: In this study, we aimed to explore the influence of ISSA on postoperative recurrence in CD patients, and the preliminary results show that ISSA was technically safe and feasible, and appears to be effective in reducing postoperative recurrence in CD patients. However, our conclusion was underpowered due to small sample size and inadequate follow- up. We proposed ISSA be considered as another alternative option in the toolbox of inflammatory bowel disease surgeons when performing anastomosis on CD patients.