FPGA HiL Simulation of Back-to-Back Converter PMSG Wind Turbine Systems

Zhenbin Zhang,Fengxiang Wang,Metehan Acikgoz,Xinbo Cai,Ralph Kennel 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This work presents a back-to-back power converter Permanent-magnet Synchronous Generator (PMSG) wind turbine real-time simulation system based on FPGA Hardware-in-the-Loop (HiL) concept. The proposed system can be used for Electric Control Units (ECUs) evaluation in a real-time manner. The refreshing rate effect of a HiL emulator is discussed and analyzed with real-time simulation proof. Within this work, perunit system model of a 2MW Back-to-Back converter direct-drive PMSG wind turbine system is developed both in continuous and discrete formats. The effectiveness of the discrete per-unit system model is firstly verified through off-line simulation in Matlab/Simulink environment. Then by using a so-called Single-Cycle-Timed- Loop (SCTL) technique, the per-unit discrete system model is implemented on an FPGA based platform as the emulator, achieving a very high refreshing-rate (up to 250 kHz, i.e., 4μs). The emulator refreshing rate effect is evaluated in a real-time operating manner by implementing an ECU (using FOC/VOC control scheme) in a second FPGA chassis. At the end of this paper the results are analyzed and theoretically interpreted.

Frequency Synchronization of Three-Phase Grid-Connected Inverters Controlled as Current Supplies

Zhenbin Fu,Zhihua Feng,Xi Chen,Xinxin Zheng,Jing Yin 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In a three-phase system, three-phase AC signals can be translated into two-phase DC signals through a coordinate transformation. Thus, the PI regulator can realize a zero steady-state error for the DC signals. In the control of a three-phase grid-connected inverter, the phase angle of grid is normally detected by a phase-locked loop (PLL) and takes part in a coordinate transformation. A novel control strategy for a three-phase grid-connected inverter with a frequency-locked loop (FLL) based on coordinate transformation is proposed in this paper. The inverter is controlled as a current supply. The grid angle, which takes part in the coordinate transformation, is replaced by a periodic linear changing angle from –π to π. The changing angle has the same frequency but a different phase than the grid angle. The frequency of the changing angle tracks the grid frequency by the negative feedback of the reactive power, which forms a FLL. The control strategy applies to non-ideal grids and it is a lot simpler than the control strategies with a PLL that are applied to non-ideal grids. The structure of the FLL is established. The principle and advantages of the proposed control strategy are discussed. The theoretical analysis is confirmed by experimental results.

High-Reliability Three-Phase Dual-Buck Grid-Connected Inverter without Shoot-Through Problem

Zhenbin Fu,Zhihua Feng,Xi Chen,Xinxin Zheng 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

When compared to traditional bridge-type inverters, the dual-buck inverter has a higher reliability due to the fact that its bridge legs do not have a shoot-through problem. In this paper, the working principle of the dual-buck inverter is analyzed. A comparison of the working modes under full-cycle and half-cycle control is discussed. With half-cycle control, the inverter can realize a higher efficiency. However, this results in current zero-crossing distortion. The corresponding control strategy of the dual-buck inverter is proposed in order to realize both high efficiency and low current harmonic distortion. In addition, the system stability is analyzed. Dead-time is unnecessary due to the advantages of the topology. Thus, the current harmonic distortion can be further reduced. An inverter with the proposed control strategy has the advantages of high reliability, high efficiency and low current harmonic distortion. Finally, simulation and experimental results are given to verify the theoretical analysis.

Isolation and Characterization of Collagen from the Muscle of Amur Sturgeon (Acipenser schrenckii)

Zhenbin Wang,Lin Wang,Shiman Lin,Qiufang Liang,Zhujun Shi,Junmin Xu,Haile Ma 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5

The collagen in Amur sturgeon muscle wasisolated using sodium chloride (salt-solubilized collagen,SSC, 3.02%), followed by acetic acid (acid-solubilizedcollagen, ASC, 31.56%) and then pepsin (pepsin-solubilizedcollagen, PSC, 58.49%). The collagens appeared to bedense sheet-like film linked by random-coiled filamentsunder SEM. There was no obvious difference in denaturationtemperature (about 33°C) assessed by CD, while themelting temperature of SSC (115.82°C) was significantlylower than ASC and PSC (120.23 and 118.80°C, respectively)determined by DSC. SDS-PAGE showed that the collagenswere mainly type I with similar amino acid profiles. FTIRconfirmed the triple helical structure of the collagens,and indicated more hydrogen bond in PSC and moreintermolecular crosslinks in ASC. These results providesome basis for elucidating the function of collagen in thedevelopment of meat texture during postmortem aging andprocessing.

Frequency Synchronization of Three-Phase Grid-Connected Inverters Controlled as Current Supplies

Fu, Zhenbin,Feng, Zhihua,Chen, Xi,Zheng, Xinxin,Yin, Jing The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

In a three-phase system, three-phase AC signals can be translated into two-phase DC signals through a coordinate transformation. Thus, the PI regulator can realize a zero steady-state error for the DC signals. In the control of a three-phase grid-connected inverter, the phase angle of grid is normally detected by a phase-locked loop (PLL) and takes part in a coordinate transformation. A novel control strategy for a three-phase grid-connected inverter with a frequency-locked loop (FLL) based on coordinate transformation is proposed in this paper. The inverter is controlled as a current supply. The grid angle, which takes part in the coordinate transformation, is replaced by a periodic linear changing angle from $-{\pi}$ to ${\pi}$. The changing angle has the same frequency but a different phase than the grid angle. The frequency of the changing angle tracks the grid frequency by the negative feedback of the reactive power, which forms a FLL. The control strategy applies to non-ideal grids and it is a lot simpler than the control strategies with a PLL that are applied to non-ideal grids. The structure of the FLL is established. The principle and advantages of the proposed control strategy are discussed. The theoretical analysis is confirmed by experimental results.

High-Reliability Three-Phase Dual-Buck Grid-Connected Inverter without Shoot-Through Problem

Fu, Zhenbin,Feng, Zhihua,Chen, Xi,Zheng, Xinxin The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

When compared to traditional bridge-type inverters, the dual-buck inverter has a higher reliability due to the fact that its bridge legs do not have a shoot-through problem. In this paper, the working principle of the dual-buck inverter is analyzed. A comparison of the working modes under full-cycle and half-cycle control is discussed. With half-cycle control, the inverter can realize a higher efficiency. However, this results in current zero-crossing distortion. The corresponding control strategy of the dual-buck inverter is proposed in order to realize both high efficiency and low current harmonic distortion. In addition, the system stability is analyzed. Dead-time is unnecessary due to the advantages of the topology. Thus, the current harmonic distortion can be further reduced. An inverter with the proposed control strategy has the advantages of high reliability, high efficiency and low current harmonic distortion. Finally, simulation and experimental results are given to verify the theoretical analysis.

Transcriptome analysis revealed regulatory mechanisms of light and culture density on free-living sporangial filaments of Neopyropia yezoensis (Rhodophyta)

Bangxiang He,Zhenbin Zheng,Jianfeng Niu,Xiujun Xie,Guangce Wang 한국조류학회I 2023 ALGAE Vol.38 No.4

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation–brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

Current Balancing Control of High Power Parallel-Connected AFE with Small Current Ripples

Xinbo Cai,Zhenbin Zhang,Liang Cai,Ralph Kennel 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Parallel connected Active Front End (AFE) voltage converters are widely employed in high-power grid interfaces for renewable energy applications. With parallel connected two level power converters, the power rating of the system can be easily increased with higher stability and less control efforts than multilevel power converter based solutions. However, due to unmatched modules, unbalanced currents inevitably happen to different modules of the same phase, which seriously impacts the efficiency and performances of the converter. This paper presents an improved current balancing control methods for a high power (600 kVA) parallel connected AFE for wind energy applications. The proposed current balancing method is integrated within a well-known Voltage Oriented Control Scheme with few implementation efforts. The simulation results show that with the proposed strategy the current ripples of each parallelconnected converter leg decrease evidently and the THDs are therefore decreased. Moreover, the effectiveness of the proposed method is also confirmed by experimental results with a grid-code compatible testing set-up.

Saliency Detection based on Global Color Distribution and Active Contour Analysis

( Zhengping Hu ),( Zhenbin Zhang ),( Zhe Sun ),( Shuhuan Zhao ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.12

In computer vision, salient object is important to extract the useful information of foreground. With active contour analysis acting as the core in this paper, we propose a bottom-up saliency detection algorithm combining with the Bayesian model and the global color distribution. Under the supports of active contour model, a more accurate foreground can be obtained as a foundation for the Bayesian model and the global color distribution. Furthermore, we establish a contour-based selection mechanism to optimize the global-color distribution, which is an effective revising approach for the Bayesian model as well. To obtain an excellent object contour, we firstly intensify the object region in the source gray-scale image by a seed-based method. The final saliency map can be detected after weighting the color distribution to the Bayesian saliency map, after both of the two components are available. The contribution of this paper is that, comparing the Harris-based convex hull algorithm, the active contour can extract a more accurate and non-convex foreground. Moreover, the global color distribution can solve the saliency-scattered drawback of Bayesian model, by the mutual complementation. According to the detected results, the final saliency maps generated with considering the global color distribution and active contour are much-improved.

Compressive Sensing Based Predictive Current Control of Electrical Drives

Ferdinand Grimm,Zhenbin Zhang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

We propose a novel control approach for two level inverter drives that is based on a reformulation of the model predictive current control framework. Using inverse modeling we define a sparse optimization problem to achieve the control goal. In order to reduce the computational effort the optimization problem is relaxed to an l1-minimization. A structured iterative hard thresholding algorithm is proposed to solve the `1-minimization. Furthermore, an outlook to multistep model predictive control is given. The results are then verified by means of simulations.