Power Supply Path Research Articles

Design and experimental evaluation on an advanced multisource energy harvesting system for wireless sensor nodes.

An effective multisource energy harvesting system is presented as power supply for wireless sensor nodes (WSNs). The advanced system contains not only an expandable power management module including control of the charging and discharging process of the lithium polymer battery but also an energy harvesting system using the maximum power point tracking (MPPT) circuit with analog driving scheme for the collection of both solar and vibration energy sources. Since the MPPT and the power management module are utilized, the system is able to effectively achieve a low power consumption. Furthermore, a super capacitor is integrated in the system so that current fluctuations of the lithium polymer battery during the charging and discharging processes can be properly reduced. In addition, through a simple analog switch circuit with low power consumption, the proposed system can successfully switch the power supply path according to the ambient energy sources and load power automatically. A practical WSNs platform shows that efficiency of the energy harvesting system can reach about 75–85% through the 24-hour environmental test, which confirms that the proposed system can be used as a long-term continuous power supply for WSNs.

Simulation Based Framework for Accurately Estimating Dynamic Power-Supply Noise and Path Delay

Power-supply noise is one of the major contributing factor for yield loss in sub-micron designs. Excessive switching in test mode causes supply voltage to droop more than in functional mode leading to failures in delay tests that would not occur otherwise under normal operation. Thus, there exists a need to accurately estimate on-chip supply noise early in the design phase to meet power requirements in normal mode and during test to prevent overstimulation during the test cycle and avoid false failures. Simultaneous switching activity (SSA) of several logic components is one of the main sources of power-supply noise (PSN) which results in reduction of supply voltages at the power-supplies of the logic gates. Most existing techniques and tools predict static IR-drop, which accounts for only part of the total voltage drop on the power grid. To our knowledge, inductive drop is not included in current noise analysis for simplification. The power delivery networks in today's very deep-submicron chips are susceptible to slight variations and cause sudden large current spikes leading to higher Ldi � dt than resistive drop essentiating the need to account for this drop. Power-supply noise also impacts circuit operation incurring a significant increase in path delays. However, it is infeasible to carry out full-chip SPICE-level simulations on a design to validate the ATPG generated test patterns. Accurate and efficient techniques are required to quantify supply noise and its impact on path delays to ensure reliable operation in both mission mode and during test. We present a scalable current-based dynamic method to estimate both IR and Ldi / dt drop caused by simultaneous switching activity and use the technique to predict the increase in path delay. Our technique uses simulations of individual extracted paths in comparison to time-consuming full-chip simulations and thus it can be integrated with existing ATPG tools. The method uses these path simulations and a convolution-based technique to estimate power-supply noise and path delays. Simulation results for combinational and sequential benchmark circuits are presented demonstrating the effectiveness of our techniques.

Analysis of Switching Overvoltage in Regional Grid with Small Hydropower Plants

Present-day small hydropower plants (SHPs) have a large development potential because of the increasing interest in renewable resources and distributed energy generation, therefore, there are many SHPs in places of China where are rich in water resources. However, it has caused overvoltages in the distribution network, and which is even worse for the switching overvoltage such as isolated network operation, changing power supply path. The simple network model is used to analyze the reasons of the switching overvoltage, and the simulation software DIgSILENT/PowerFactory is used to check out the results of the theoretical analysis.

A Matrix Method for Describing the Power Transmission of Electric Network

Traditional power flow calculation can only supply the information of the conventional electric parameters, such as node voltage, branch current, power, etc. The transmission of power which is injected into the network by each power source, including power supply paths, power belongs, relationship among the power injected into each nodes, cannot be given. To solve this problem, this paper using the theory of the physical distribution of power network’s energy, proposes a matrix method for describing the power transmission, expresses the value and supply paths of the power from each single source in power network with the analytic method.

The Development of Software of Self-Healing Analysis Base on the Analysis of Power Supply Path in Regional Power Network

At present, dispatchers analyze the power transmission from change of operation modes always by their own experiences, so currency of the result cannot be proved. Also, because these works depend on recognize of dispatcher to electrical system, objective of the result cannot be proved. For this problem, we developed this software based on the analysis of power supply path. It reveals inherent laws of power transmission in network and provides an analyzing and assisting tool for dispatchers.