Current Issue : April - June Volume : 2018 Issue Number : 2 Articles : 5 Articles
Piezoelectric vibration based energy harvesting systems have been widely utilized and\nresearched as powering modules for various types of sensor systems due to their ease of integration\nand relatively high energy density compared to RF, thermal, and electrostatic based energy harvesting\nsystems. In this paper, a low-power CMOS full-bridge rectifier is presented as a potential solution\nfor an efficient energy harvesting system for piezoelectric transducers. The energy harvesting\ncircuit consists of two n-channel MOSFETs (NMOS) and two p-channel MOSFETs (PMOS) devices\nimplementing a full-bridge rectifier coupled with a switch control circuit based on a PMOS device\ndriven by a comparator. With a load of 45 k�©, the output rectifier voltage and the input piezoelectric\ntransducer voltage are 694 mV and 703 mV, respectably, while the VOUT versus VIN conversion ratio\nis 98.7% with a PCE of 52.2%. The energy harvesting circuit has been designed using 130 nm standard\nCMOS process....
In this paper, a complete computer aided procedure based on the power density concept\nand aimed at the automatic design of EMI filters for power electronic converters is presented. It is\nrule-based, and it uses suitable databases built-up by considering information on passive components\navailable from commercial datasheets. The power density constraint is taken into consideration by\nimposing the minimization of the filter volume and/or weight; nevertheless, the system in which\nthe automatically designed filter is included satisfies the electromagnetic compatibility standards\nlimits. Experimental validations of the proposed procedure are presented for two real case studies,\nfor which the performance and the size of the best filter design are compared with those related to a\nconventionally designed one....
Power optimization is a very important and challenging step in the physical design flow,\nand it is a critical success factor of an application-specific integrated circuit (ASIC) chip. Many\ntechniques are used by the place and route (P&R) electronic design automation (EDA) tools to meet\nthe power requirement. In this paper, we will evaluate, independently from the library file, the impact\nof redefining the max transition constraint (MTC) before the power optimization phase, and we will\nstudy the impact of over-constraining or under-constraining a design on power in order to find the\nbest trade-off between design constraining and power optimization. Experimental results showed\nthat power optimization depends on the applied MTC and that the MTC value corresponding to\nthe best power reduction results is different from the default MTC. By using a new MTC definition\nmethod on several designs, we found that the power gain between the default methodology and the\nnew one reaches 2.34%....
DC microgrids look attractive in distribution systems due to their high reliability, high efficiency, and easy integration with\nrenewable energy sources. The key objectives of the DC microgrid include proportional load sharing and precise voltage\nregulation. Droop controllers are based on decentralized control architectures which are not effective in achieving these objectives\nsimultaneously due to the voltage error and load power variation. A centralized controller can achieve these objectives using a high\nspeed communication link. However, it loses reliability due to the single point failure. Additionally, these controllers are realized\nthrough proportional integral (PI) controllers which cannot ensure load sharing and stability in all operating conditions. To address\nlimitations, a distributed architecture using sliding mode (SM) controller utilizing low bandwidth communication is proposed\nfor DC microgrids in this paper. The main advantages are high reliability, load power sharing, and precise voltage regulation.\nFurther, the SM controller shows high robustness, fast dynamic response, and good stability for large load variations. To analyze\nthe stability and dynamic performance, a system model is developed and its transversality, reachability, and equivalent control\nconditions are verified. Furthermore, the dynamic behavior of the modeled system is investigated for underdamped and critically\ndamped responses. Detailed simulations are carried out to show the effectiveness of the proposed controller....
The stochastic dynamic interval model of power systems with asynchronous wind turbine generators is established with\nconsideration of the interval uncertain parameters and random small excitation disturbances. The conditions of interval mean\nstability and interval mean square stability of the power systems are proposed. The relationship between the bounds of the mean\n(mean square) error and the parameter interval range of the systems is discussed. Finally, we simulate the power systems to\ndemonstrate the effectiveness of the proposed results....
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