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In recent years, people pay more and more attention to the knowledge of health care and longevity. As an important branch of the Traditional Chinese Medicine (TCM), health preservation is a subject for studying the theories and methods to prevent diseases and to maintain personal health. We aim to provide the general public as well as the TCM practitioners and students with a convenient way to access...
Thick film hybrid integrated circuit is a product of thick film technology and semiconductor technology. Because of some outstanding advantages, such as high reliability and high integration, hybrid integrated circuit has been gradually applied to aerospace electronic equipment. The situation of unstable electrical performance caused by individual parameters exceed standard in the hybrid integrated...
In this paper a kind of SSPC was designed and fabricated using thick film hybrid circuit technology. More than 1000 SSPC products went through the screening test according to GJB2438A. The screening procedure including thermal shock, high temperature power burn-in test, constant acceleration, hermetic sealing test and particle impact noise detection (PIND). Also 1000h life test was applied to samples...
This paper proposes a new bidirectional resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant DC-DC converters, and meanwhile achieves high efficiency. It is realized by configuring a full-bridge mode and a half-bridge mode operation during each switching cycle...
When distributed energy storage units (DESUs) in islanded ac microgrid are controlled by conventional P-f droop control, the state-of-charge (SOC) of DESUs becomes unbalanced due to the inconsistent line impedances and initial SOC. In order to achieve SOC balancing, an improved droop control is presented in this paper. The SOC balancing of DESUs and frequency regulation can be realized by adding a...
Middlebrook impedance analysis method is considered to be an efficient method in analyzing the high-frequency stability. This method has the two deficiency: firstly, the partition between source and load subsystems is unclear; secondly, the analysis procedure is complicated. Partition between source and load subsystems in hybrid networking islanded-microgrid is researched in this paper. An efficient...
In this paper we propose an automatic urban building extraction method for oblique aerial images. Five steps are included in this method: point cloud generation, grid partition, feature extraction, building detection and building reconstruction. Taking advantages of recent progress in large-scale Structure from Motion (SfM) and Multiple View Stereo (MVS), dense point cloud is generated first. Then,...
In LLC resonant converters, the variable duty-cycle control is usually combined with a variable frequency control to widen the gain range, improve the light-load efficiency, or suppress the inrush current during start-up. However, a proper analytical model for the variable duty-cycle controlled LLC converter is still not available due to the complexity of operation modes and the nonlinearity of steady-state...
This work presents sea wind speed model and wind disturbance model for Dynamic Positioning (DP) simulator. There were several problems in the existing DP simulator: wind speed was constant, or wind coefficients of wind disturbance was taken as to the feedforward force wind coefficients directly, or wind speed was not filtered. It caused that the feedforward force was equal to the wind disturbance,...
This paper develops an improved model predictive controller (MPC) for the dynamic positioning system of vessels by using the Laguerre functions. The set of Laguerre networks is introduced to describe the future control increment trajectory, which has fewer parameter to adjust. The improved model predictive controller have the advantages of the traditional model predictive control, which has the good...
Microgrid inverters using droop control will lead voltage and frequency at PCC to deviate from the rating in islanding mode and the droop coefficients will affect stability margin of the system. In order to reduce voltage and frequency deviations at PCC and enhance the stability margin of the microgrid, an optimized control strategy is proposed in this paper. The proposed method defines the objective...
Due to the fact that the line impedances in microgrid and initial value of State-of-Charge(SoC) are different, SoC of energy storage systems (ESS) in microgrid is unbalance and exists the phenomenon of overcharge and overdischarge of the ESS. At the same time, the conventional droop control used for balancing the output power of the inverters lead to voltage deviation in the ac island microgrid. In...
Aiming at the problems in view of existing obstacle detection method, such as low adaptability and low recognition rate in the environment of lighting, multi-objective and background interference, an obstacle detection method based on restricted region growing and saturation characteristics is proposed. Firstly, the original image containing the edge information is processed by the restricted region...
This paper presents the dual-band filter design with pole-zero distribution in the complex frequency plane. Based on specifications, the poles and zeros of each passband can be distributed as desired, such as having poles on typical Butterworth/Bessel circle, Chebyshev ellipse, etc. This can provide different passband responses to meet different specifications of each band. In order to make more obvious...
A useful fast charging method should make a balance between battery's safety/cycle life and charging time. So, the internal temperature or energy loss of battery should be controlled in charging process. This paper proposes a charging method for Li-ion battery bank to balance both energy loss and charging time. Firstly, the method gives a procedure to get the function of the internal direct current...
Bidirectional buck/boost converter is widely used in new energy storage systems. By utilizing the traditional triangular current mode (TCM) control strategy, soft-switching can be achieved for all switches. However, traditional TCM scheme needs current zero-crossing detection to regulate conduction interval and a feed-forward regulator is needed due to detection delay, which make the control more...
Based on microgrid frequency, a new photovoltaic (PV)/ battery (BA)/ fuel cell (FC) hybrid energy management strategy with modified droop control for islanded application is proposed in this paper. This strategy enables the plug and play capability in the distributed units with voltage control mode and makes it possible to avoid using the communication line or a central supervisor. The system frequency...
In this paper, a center-tapped transformer based bidirectional dc-dc converter with full ZVS operating range is proposed for wide input voltage range applications. The soft switching analysis in different modes is carried out and a simple and effective control strategy, allowing extending the practical ZVS to the whole operating range, is proposed. By dynamically adjusting the phase-shift angle between...
An improved buck-boost + LLC (IBB LLC) cascaded converter appropriate for wide input voltage situation is presented in this paper, which can be used as a constant voltage source or a constant current source charger for battery. The control strategy of dual frequency PWM (DFPWM) is introduced. For the LLC converter, ZVS for MOSFETs and ZCS for diode are achieved. As a result, the switching loss is...
Two stage cascaded converters are widely used in bidirectional applications, but the negative impedance may cause system instability. Actually the impedance interaction is much different between forward power flow and reversed power flow, which will introduce more uncertainty to the system stability. This paper proposes a control method for the constant power controlled converter in cascaded system,...
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