Effect of grid inductance on grid current quality of parallel grid-connected inverter system with output LCL filter and closed-loop control

The dynamical model of laser cladding width is identified by the method of step response experiments. Mathematical models between the cladding width and the laser power, the scanning speed, or the powder flowrate are established respectively according to corresponding experimental results. Simulating experiment results verify the validity of these models. The dynamical identification lays foundation for the closed loop control in laser shaping process so as to improve the quality of the laser formed parts.

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A Control Strategy of a Single-phase H6-type Grid-connected Inverter with Low Harmonic Current

MATEC Web of Conferences ◽

10.1051/matecconf/201817302041 ◽

2018 ◽

Vol 173 ◽

pp. 02041

Author(s):

Lin Chunxu ◽

Zhou Chunhua ◽

Li Wei ◽

Chen Rui

Keyword(s):

Control Strategy ◽

Single Phase ◽

Closed Loop ◽

High Efficiency ◽

Control Method ◽

Harmonic Distortion ◽

Outer Loop ◽

Lcl Filter ◽

Loop Control ◽

Grid Connected Inverter

In order to reduce the total harmonic distortion (THD) of the grid-connected current caused by the high-frequency switching of the inverter, this paper combines the high efficiency single-phase H6-type inverter with LCL filter. The double closed-loop control method that consists of grid-connected current outer loop and capacitor current inner loop is put forward, by which a resonance peak of a low damping LCL filter is eliminated. In the grid-connected current outer loop, quasi proportion resonant (QPR) controller is adopted to overcome the steady-state error and weak anti-jamming capability in traditional PI controller. Finally, a simulation model is built in SIMULINK to verify the research. The simulation results show that, based on the single-phase H6-type inverter and LCL filter, the double closed-loop QPR control strategy can achieve the static error free tracking control of grid-connected current, which makes the system more stable and reduces the THD of grid-connected current effectively.

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A novel dual closed-loop control scheme based on repetitive control for grid-connected inverters with an LCL filter

ISA Transactions ◽

10.1016/j.isatra.2018.01.029 ◽

2018 ◽

Vol 74 ◽

pp. 194-208 ◽

Cited By ~ 19

Author(s):

Yun-Guang Gao ◽

Fa-Yang Jiang ◽

Jian-Cheng Song ◽

Li-Jun Zheng ◽

Fei-Yan Tian ◽

...

Keyword(s):

Closed Loop ◽

Repetitive Control ◽

Closed Loop Control ◽

Lcl Filter ◽

Loop Control ◽

Control Scheme

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Online Closed-Loop Control Using Tactile Feedback Delivered Through Surface and Subdermal Electrotactile Stimulation

Frontiers in Neuroscience ◽

10.3389/fnins.2021.580385 ◽

2021 ◽

Vol 15 ◽

Author(s):

Jian Dong ◽

Winnie Jensen ◽

Bo Geng ◽

Ernest Nlandu Kamavuako ◽

Strahinja Dosen

Keyword(s):

Closed Loop ◽

Online Control ◽

Tactile Feedback ◽

Closed Loop Control ◽

Loop Control ◽

Minimal Invasiveness ◽

Electrotactile Stimulation ◽

Significant Difference ◽

The Impact

AimLimb loss is a dramatic event with a devastating impact on a person’s quality of life. Prostheses have been used to restore lost motor abilities and cosmetic appearance. Closing the loop between the prosthesis and the amputee by providing somatosensory feedback to the user might improve the performance, confidence of the amputee, and embodiment of the prosthesis. Recently, a minimally invasive method, in which the electrodes are placed subdermally, was presented and psychometrically evaluated. The present study aimed to assess the quality of online control with subdermal stimulation and compare it to that achieved using surface stimulation (common benchmark) as well as to investigate the impact of training on the two modalities.MethodsTen able-bodied subjects performed a PC-based compensatory tracking task. The subjects employed a joystick to track a predefined pseudorandom trajectory using feedback on the momentary tracking error, which was conveyed via surface and subdermal electrotactile stimulation. The tracking performance was evaluated using the correlation coefficient (CORR), root mean square error (RMSE), and time delay between reference and generated trajectories.ResultsBoth stimulation modalities resulted in good closed-loop control, and surface stimulation outperformed the subdermal approach. There was significant difference in CORR (86 vs 77%) and RMSE (0.23 vs 0.31) between surface and subdermal stimulation (all p < 0.05). The RMSE of the subdermal stimulation decreased significantly in the first few trials.ConclusionSubdermal stimulation is a viable method to provide tactile feedback. The quality of online control is, however, somewhat worse compared to that achieved using surface stimulation. Nevertheless, due to minimal invasiveness, compactness, and power efficiency, the subdermal interface could be an attractive solution for the functional application in sensate prostheses.

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Use of a Heating System to Control the Probiotic Beverage Production in Batch Bioreactor

Applied Sciences ◽

10.3390/app11010084 ◽

2020 ◽

Vol 11 (1) ◽

pp. 84

Author(s):

Jožef Ritonja ◽

Andreja Goršek ◽

Darja Pečar

Keyword(s):

Control System ◽

Fermentation Process ◽

Closed Loop ◽

Closed Loop Control ◽

Loop Control ◽

Batch Bioreactor ◽

Closed Loop Control System ◽

Loop Control System ◽

The Impact

Fermentation is a crucial bioengineering process, existentially important for modern society. The most commonly used production unit for this process is the batch bioreactor. Its main advantage is unsophisticated construction, which unfortunately results in its incapability of controlling the transient state of the fermentation process. Control of the fermentation can significantly improve the quality of the product and the economy of the process; therefore, it is useful for bioreactors to be equipped with a control system. Based on the experimental results, we used an optimization method to identify a mathematical model that describes the impact of the bioreactor’s temperature on the fermentation’s transient process. The obtained model was applied for the design and synthesis of the closed-loop control system. Simulations and experiments confirmed the effectiveness of the proposed control system. In this way, we can ensure the consistent quality of the produced probiotic product, increase the amount of the product, and shorten the fermentation time. The original results display the feasibility of the closed-loop control of the batch bioreactor’s fermentation process by changing the temperature. So far, the process has been carried without a closed-loop control system. The problem is current and has not yet been solved sufficiently. There are many attempts published; one of the last shows the possibility of controlling the fermentation process by changing the oxygen supply, which is more complex and expensive for realization than the solution from our study.

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