Online Noninvasive Technique for Condition Monitoring of Capacitor in Linear Power Supplies
Abstract : Linear power supplies (LPSs) are widely used in fields including measurement systems, radiofrequency systems, medical applications, nuclear power plants, and spacecraft electronics. Electrolytic capacitors are used in a variety of devices because of their small size, low cost, and large capacity. During the use of electrolytic capacitor, it is very common for the capacitance ( C ) to decrease and its equivalent series resistance (ESR) to increase, which are typical indicators of capacitor degradation. Electrolytic capacitors are both the weak link and the core component of the LPSs and play a vital role in determining the LPSs lifetime. Under the power frequency condition, the power frequency transformer plays a role in isolation and voltage reduction in the LPSs. The input and output signals of the LPSs are used for condition monitoring of capacitor, and the existence of transformer increases the difficulty of the online noninvasive technique of LPSs. The online noninvasive technique for condition monitoring of capacitor in LPSs proposed in this article can be solved only by using the input current, the magnetizing current, the input voltage, and the load current. Effect of temperature on C and ESR values is incorporated for accurate determination of the parameters of capacitor. The effectiveness of the proposed method is verified through simulations and experiments, and the data obtained are consistent with the results measured using an LCR meter.
? This condition is indicated by hi-lo or lo-hi transition of the S/H output.
? At this point the estimator enters sleep mode and only occasionally is re-engaged upon the exit of a transient or after a pre-defined wait time.
? As such, they are not most suitable for the targeted cost-sensitive low-power dc-dc supplies. The invasive solutions, presented in, eliminate the RC filter and the need for a dedicate ADC.
? An accurate estimation of that constant and/or emulation of the realistic capacitor behavior is of a key importance for fast transient response control methods and implementation of the power stage health monitoring systems .
? Noninvasive glucose-level monitoring device for clinical test overcomes the problem of frequent pricking for blood samples.
? There is requirement to develop the Internet-MedicalThings (IoMT) integrated Healthcare Cyber-Physical System (H-CPS) based Smart Healthcare framework for glucose measurement with purpose of continuous health monitoring.
? There are several health issues which may also arise from diabetes like depression, digestive problem, anxiety disorders, mood disorder and eating habits change.
? The diabetes could be controlled with proper diet plan, through some physical exercise, insulin dosage and medicines.
• Both approaches were implemented and compared to validate the noninvasive method proposed in this work, even though it did not represent an actual LVR.
• The effectiveness of the proposed estimator is illustrated using a 5V-to-1V/5A, 500kHz buck converter demonstrating accuracy within a few tens of ns in the detection of capacitor zero current crossing points.
• Due to these potential advantages a number of noninvasive and invasive output capacitor timeconstant estimators have been previously proposed.
• The noninvasive estimators, which usually consist of a small RC filter placed in parallel with the output capacitor, can generally be divided into static and self-tuning.
? An upgraded version of SMA is used for the implementation of PCB.
? Because of it’s feasibility and performance, it can be considered as the first wearable device for the glucose monitoring but it is large in size which makes it inconvenient.
? However, long wave NIR has good performance in vitro testing. In similar way, the fiber-optic sensor is used along with laser based mid-infrared spectroscopy for vitro based glucose measurement.
? The Clarke error grid analysis has been considered maximum measurement for analysis which is used to check the performance of any device for accuracy measurement.
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