Yong Guan

ESR estimation method for DC-DC converters based on improved EMD algorithm

Aluminum electrolytic capacitors are usually used in DC-DC converters as smoothing capacitors. According to the statistics data, they are the weakest among various power components in the DC-DC converter. With the increase of the running time, the performance degradation of electrolytic capacitors reflects in electrical parameters, mainly the Equivalent Series Resistance (ESR) and capacitance. The best indicator of the output filter capacitor failure is the increase of ESR. And the output ripple voltage of the converter increases with respect to ESR. Monitoring the ESR variation of the electrolytic capacitor, achieving by voltage and current ripple, can estimate the health state of the converter.

A high dynamic range complementary metal-oxide-semiconductor (CMOS) camera using multi-slope response and an image reconstruction algorithm

Dynamic range is a critical figure of merit for an imaging system; it describes the observable range of brightness. This paper introduces the design of a complementary metal-oxide-semiconductor (CMOS) camera for astronomical imaging using the IBIS5 sensor. The camera achieves a high dynamic range by multi-slope response using variable reset voltages. A method to convert an image captured in multi-slope response into a linear image, and thus obtain higher contrast, is developed and analysed. Finally, observation results of the sun and the moon with this camera are presented. The results confirm the practicality of this camera and the image reconstruction method in scientific applications.

Power Supply Prognostics and Health Management of High Reliability Electronic Systems in Rugged Environment

The high reliable embedded system in rugged environment has huge potential application value. There are 34% faults in electronic system by the cause of the fault of power system. So the prognostics mechanism and the algorithm of power health has been a core support technology in applications. the fault and the deterioration and healing model of the power system in rugged environment is constructed by analysis of FFP, DFP and healing(alleviation)for improving the reliability, the usability and the maintainability. And many questions such as fixed-time maintenance and back-down maintenance depending on conventional statistical method are solved fundamentally. Finally, the prognostics and health management methods of power health in domestic and foreign presently are contrasted and analyzed.

Design and evaluation of a high-performance charge coupled device camera for astronomical imaging

The Space Solar Telescope (SST) is the first Chinese space astronomy mission. This paper introduces the design of a high-performance 2K × 2K charge coupled device (CCD) camera that is an important payload in the Space Solar Telescope. The camera is composed of an analogue system and a digital embedded system. The analogue system is first discussed in detail, including the power and bias voltage supply circuit, power protection unit, CCD clock driver circuit, 16 bit A/D converter and low-noise amplifier circuit. The digital embedded system integrated with an NIOS II soft-core processor serves as the control and data acquisition system of the camera. In addition, research on evaluation methods for CCDs was carried out to evaluate the performance of the TH7899 CCD camera in relation to the requirements of the SST project. We present the evaluation results, including readout noise, linearity, quantum efficiency, dark current, full-well capacity, charge transfer efficiency and gain. The results show that this high-performance CCD camera can satisfy the specifications of the SST project.

Failure prediction of electrolytic capacitors in Switching-Mode Power Converters

The degradation of electrolytic capacitor is the cause of most faults of Switching-Mode Power Converters. Various tests showed that the increase of the internal Equivalent Series Resistance (ESR) of the capacitors is good indicator of their faulty state. This paper presents the equivalent model of electrolytic capacitor, analyzes several different methods of detecting the value of ESR, and proposes a new method to realize the accurate measurement of ESR. The proposed method obtains the amplitude-frequency characteristics and phase-frequency characteristics of the power systems by black-box testing. In addition, it is shown that these characteristics shifted after the deterioration of the filter capacitor. The actual value of ESR is taken out from these shifted characteristics and the equations. At the end of this paper, a series of experimental results are shown to verify the proposed prediction methodology.

Design and characteristics measurement of a high-speed CMOS imaging system

This paper introduces the design of a high-speed 2K × 2K CMOS imaging system that is part of a Wide Field Monitor System proposed in China recent years. The CMOS sensor used in this imaging system is LUPA-4000 from Cypress corp. This CMOS camera is composed of an analogue system and a digital embedded system. The digital embedded system integrated with an NIOS II soft-core processor serves as the control and data acquisition system of the camera. In addition, research on characteristics measurement for CMOS imagers was carried out, including readout noise, linearity, quantum efficiency, pixel non-uniformity, dark current, full-well capacity, and gain. The photon transfer technique is adopted to evaluate the gain and readout noise. At last, the evaluation results of the high-speed CMOS imaging system are shown. The results indicate that this high-speed CMOS camera can meet the requirements of the whole Wide Field Monitor System.

An introduction to the variable neighborhood and the related adaptive determination algorithm

The neighborhood-based multi-granulations rough set (NMGRS) is the latest extended model of the multi-granulations rough set (MGRS), which makes the MGRS can deal with real-value data. As one of the most important parameters, the neighborhood size has a significant impact on attribute reduction. However, the common methods to get a neighborhood size rely on keeping trying different values and experiences. And all the attributes are assigned the same value, which ignores their differences on the distribution and the contribution to the decision. Therefore, this paper proposes a new algorithm which assigns adaptively different attributes different neighborhood sizes (it is defined as the variable neighborhood) according to the data distributions. The minimal between class distances of each attribute is regarded as a very important indicator to form such a neighborhood size. The results of experiments on different types of data sets prove that the proposed algorithm can get a better attribute reduction and further make the NMGRS more pervasive and practical.

The Supercapacitor Degradation State Diagnostic System Based on LabVIEW

In this thesis, we design and implement the degradation state diagnostic system for supercapacitor. In order to detect the degradation degree of supercapacitor, it is necessary to test the changes of the parameters that include capacitance, ESR (equivalent series resistance) and the leakage current between the terminals of supercapacitor. The way to obtain these parameters is to measure the voltage and current value by the data acquisition card, and then transmit to the software of LabVIEW calculating the values. By comparing the values of capacitance and ESR with the original value separately, the degradation state of the supercapacitor can be estimated.

The analysis of power fault mode based on discrepancy relation

The power supply is a typical equipment. It is used widely. At the same time, it is difficult to solve its fault diagnosis problem by using general or traditional fault diagnosis theory and method, because of its uncertainty, fuzzy and other questions. Rough Set (RS) represents the uncertainly technology which provides an effective approach to resolve these issues, receives more academic attention nowadays. During the process of fault diagnosis, people always face incomplete information systems due to data measurement, obtaining restrictions and other reasons. However, the classical RS theory is based on the complete system. So we proposed a new method about data filling on the basis of discrepancy relation. Experiment shows that this method can effectively increase the precision and decrease the conflict rate.

Application in DSP/FPGA design of Matlab/Simulink

As an off-line simulation tool, the modular modelling method of Matlab/Simulik has the features of high efficiency and visualization. In order to realize the fast design and the simulation of prototype systems, the new method of SignalWAVe/Simulink mix modelling is presented, and the Reed-Solomon codec encoder-decoder model is built. Reed-Solomon codec encoder-decoder model is simulated by Simulink. Farther, the C language program and model the. out executable file are created by SignalWAVe RTW Options module, which completes the hard ware co-simulation. The simulation result conforms to the theoretical analysis, thus it has proven the validity and the feasibility of this method.