Aircraft electromagnetic compatibility

Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting

Voltage regulation of unbalanced distribution network with distributed generators through genetic algorithm

Energy demand has rapidly increased since the manufacturing revolution in the 19th century. One of the higher energy demands is electricity. The great majority of devices in the manufacturing field run on electricity. The vertically integrated grid paradigm has to be changed to supply the increase in the electrical demand residentially and commercially. Distributed generators (DG) such as Photovoltic (PV) is used to supply the increase in the electrical demand. Photovoltaic (PV) is one of the fast growing distributed generators (DG) as a renewable energy source. However, installing many PV systems to the distribution system can cause power quality problems such as over voltage. This would be more concern in an unbalanced electrical distribution network where nowadays most of the PV systems are connected. PV system should coordinate with other DGs and already existing voltage regulators such as on load tap changer (OLTC) on voltage regulation so that they can support the electrical grid without adding voltage problems. This dissertation focuses on voltage regulation of unbalanced distribution system through the utilization of PV reactive power feature by minimizing the system losses using genetic algorithm. The proposed method provides a single phase controlled PV system that regulates each phase voltage individually and focuses in maintaining the voltage for each phase within a certain limit. In addition, this study proposes a single-phase OLTC control by changing the tap position individually using loss minimization. The proposed algorithm is implemented in Matlab and Simulink. Results show that the PV reactive power can be utilized to control the system voltage as well as to minimize the traditional voltage regulator operations

Demand-Side Load Management Using Single-Phase Residential Static VAR Compensators

Distribution systems are going through a structural transformation from being radially-operated simple systems to becoming more complex networks to operate in the presence of the distributed energy resources (DERs) with significant levels of penetration. It is predicted that the share of electricity generation from DERs will keep increasing as the world is moving away from the power generation involving carbon-emission and towards cleaner energy sources such as solar, wind, and biofuels. However, the unstable behavior of the renewables resources presents challenges to the already existing distribution systems. One such problem is when the distribution feeder experience variable power supply due to the unpredictable behavior of renewable resources. Therefore, it becomes difficult to maintain end-of-line (EOL) voltages within an acceptable range of the ANSI C84.1 Standard. Moreover, electric utility companies consider Conservation by Voltage Reduction (CVR) as a potential solution for managing peak power demand in distribution feeders. Conservation by Voltage Reduction is the implementation of a distribution voltage strategy whereby all distribution voltages are lowered to the minimum allowed by the equipment manufacturer. This strategy is rooted in the fact that many loads consume less power when they are fed with a voltage lower than nominal. Therefore, by implementing CVR, the utility companies can potentially reduce the peak power demand and can delay the up-gradation of the distribution feeder assets. To maximize the benefits from CVR, the whole distribution feeder must participate in regulating power to lower the demand during hours of demand. Hence, there is a need for a local solution that can regulate residential voltage levels from the first customer on the distribution feeder until the EOL of the distribution network. Such a solution will not only provide flexibility to electric utilities for better control over residential voltages but it can also maximize the benefits from CVR. This dissertation presents the concept of a closed-loop Residential Static VAR Compensator (RSVC) that will allow electric utility companies to locally regulate the voltage across the distribution feeder. The proposed RSVC is a novel smart-grid device that can regulate a residential load voltage with a fixed capacitor in shunt with a reactor controlled by two bi-directional switches. The two switches are turned on and off in a complementary manner using a pulse-width modulation (PWM) technique that allows the reactor to function as a continuously-variable inductor. The proposed RSVC has several advantages compared to a conventional thyristor-based Static VAR Compensator (SVC), such as a quasi-sinusoidal inductor current, sub-cycle reactive power controllability, lower footprint for reactive components, and its realization as a single-phase device. The closed-loop RSVC contains two regulation control loops: the primary control loop regulates the customer load voltage to any desired reference voltage within ANSI C84.1 (120 V nominal $\pm$ 5\%) and a secondary loop adjusting the reference voltage to track the point of minimum power consumption by the loads. This approach to CVR has the merit of adapting to the nature of the customer load, which may or may not decrease its energy consumption under a reduced voltage. This local approach to voltage regulation and CVR is a radical departure from current CVR strategies that have been in existence for over 30 years but have not been widely adopted by electric utilities due to high costs and technical challenges

Wireless power transfer for electric vehicle

Wireless Power Transfer (WPT) systems transfer electric energy from a source to a load without any wired connection. WPTs are attractive for many industrial applications because of their advantages compared to the wired counterpart, such as no exposed wires, ease of charging, and fearless transmission of power in adverse environmental conditions. Adoption of WPTs to charge the on-board batteries of an electric vehicle (EV) has got attention from some companies, and efforts are being made for development and improvement of the various associated topologies. WPT is achieved through the affordable inductive coupling between two coils termed as transmitter and receiver coil. In EV charging applications, transmitter coils are buried in the road and receiver coils are placed in the vehicle. Inductive WPT of resonant type is commonly used for medium-high power transfer applications like EV charging because it exhibits a greater efficiency. This thesis refers to a WPT system to charge the on-board batteries of an electric city-car considered as a study case. The electric city-car uses four series connected 12V, 100A•h VRLA batteries and two in-wheel motors fitted in the rear wheels, each of them able to develop a peak power of 4 kW to propel the car. The work done has been carried out mainly in three different stages; at first an overview on the wired EV battery chargers and the charging methodologies was carried out. Afterwards, background of different WPT technologies are discussed; a full set of Figures of Merit (FOM) have been defined and are used to characterize the resonant WPTs to the variations in resistive load and coupling coefficient. In the second stage, the WPT system for the study case has been designed. In the third stage, a prototypal of the WPT system has been developed and tested. Design of the WPT system is started by assessing the parameters of the various sections and by estimating the impact of the parameters of the system on its performance. The design process of the coil-coupling has come after an analysis of different structures for the windings, namely helix and spiral, and different shapes for the magnetic core; further to the preliminary results that have shown the advantages of the spiral structure, a more detailed analysis has then been executed on this structure. The coil design has encompassed the determination of the inductive parameters of the two-coil coupling as a function of the coil distance and axial misalignment. Both the analysis and the design was assisted by a FEM-approach based on the COMSOL code. Design of the power supply stages of the WPT system has consisted of the assessment of values and ratings of a) the capacitors that make resonant the coil-coupling, b) the power devices of the PFC rectifier and of the high frequency inverter (HF) that feeds the transmitting coil, c) the power devices of the converters supplied by the receiver coil: the rectifier diode and the in-cascade chopper that feeds the battery in a controlled way. For the converters that operate at high frequency (inverter and the rectifier in the receiver section), power electronic devices of the latest generation (the so-called Wide Band Gap (WBG) devices) have been used in order to maximize the efficiency of the WPT system. A prototypal WPT battery charger was arranged by using available cards with the power and signal circuits. Relevant experimental activities were: a) measurement of the parameters of the coils, b) desk assembling of the prototype, and c) conducting tests to verify proper operation of the prototype. The thesis work includes also a brief overview of i) emerging topics on WPT systems such as on-line electric vehicle (OLEV), ii) shielding of the magnetic fields produced by a WPT system, and iii) standards on WPT operation. These three issues play a significant role in the advancement of the WPT technology. The thesis work has been carried out at the Laboratory of “Electric systems for automation and automotive” headed by Prof. Giuseppe Buja. The laboratory belongs to the Department of Industrial Engineering of the University of Padova, Italy

Overcoming the Challenges for Multichip Integration: A Wireless Interconnect Approach

The physical limitations in the area, power density, and yield restrict the scalability of the single-chip multicore system to a relatively small number of cores. Instead of having a large chip, aggregating multiple smaller chips can overcome these physical limitations. Combining multiple dies can be done either by stacking vertically or by placing side-by-side on the same substrate within a single package. However, in order to be widely accepted, both multichip integration techniques need to overcome significant challenges. In the horizontally integrated multichip system, traditional inter-chip I/O does not scale well with technology scaling due to limitations of the pitch. Moreover, to transfer data between cores or memory components from one chip to another, state-of-the-art inter-chip communication over wireline channels require data signals to travel from internal nets to the peripheral I/O ports and then get routed over the inter-chip channels to the I/O port of the destination chip. Following this, the data is finally routed from the I/O to internal nets of the target chip over a wireline interconnect fabric. This multi-hop communication increases energy consumption while decreasing data bandwidth in a multichip system. On the other hand, in vertically integrated multichip system, the high power density resulting from the placement of computational components on top of each other aggravates the thermal issues of the chip leading to degraded performance and reduced reliability. Liquid cooling through microfluidic channels can provide cooling capabilities required for effective management of chip temperatures in vertical integration. However, to reduce the mechanical stresses and at the same time, to ensure temperature uniformity and adequate cooling competencies, the height and width of the microchannels need to be increased. This limits the area available to route Through-Silicon-Vias (TSVs) across the cooling layers and make the co-existence and co-design of TSVs and microchannels extreamly challenging. Research in recent years has demonstrated that on-chip and off-chip wireless interconnects are capable of establishing radio communications within as well as between multiple chips. The primary goal of this dissertation is to propose design principals targeting both horizontally and vertically integrated multichip system to provide high bandwidth, low latency, and energy efficient data communication by utilizing mm-wave wireless interconnects. The proposed solution has two parts: the first part proposes design methodology of a seamless hybrid wired and wireless interconnection network for the horizontally integrated multichip system to enable direct chip-to-chip communication between internal cores. Whereas the second part proposes a Wireless Network-on-Chip (WiNoC) architecture for the vertically integrated multichip system to realize data communication across interlayer microfluidic coolers eliminating the need to place and route signal TSVs through the cooling layers. The integration of wireless interconnect will significantly reduce the complexity of the co-design of TSV based interconnects and microchannel based interlayer cooling. Finally, this dissertation presents a combined trade-off evaluation of such wireless integration system in both horizontal and vertical sense and provides future directions for the design of the multichip system

Reconfigurable G and C computer study for space station use. Volume 7, appendix 5 - D-200 computer family. Appendix 6 - System error analysis. Appendix 7 - Reliability derivation for candidate computers. Appendix 8 - Power converter design data. Appendix 9 - Data transmission medium design Final report, 29 Dec. 1969 - 31 Jan. 1971

D-200 computer family, system error analysis, reliability derivation, and power converter design for reconfigurable guidance and control computer - Vol.

Bidirectional Electric Vehicles Service Integration in Smart Power Grid with Renewable Energy Resources

As electric vehicles (EVs) become more popular, the utility companies are forced to increase power generations in the grid. However, these EVs are capable of providing power to the grid to deliver different grid ancillary services in a concept known as vehicle-to-grid (V2G) and grid-to-vehicle (G2V), in which the EV can serve as a load or source at the same time. These services can provide more benefits when they are integrated with Photovoltaic (PV) generation. The proper modeling, design and control for the power conversion systems that provide the optimum integration among the EVs, PV generations and grid are investigated in this thesis. The coupling between the PV generation and integration bus is accomplished through a unidirectional converter. Precise dynamic and small-signal models for the grid-connected PV power system are developed and utilized to predict the system’s performance during the different operating conditions. An advanced intelligent maximum power point tracker based on fuzzy logic control is developed and designed using a mix between the analytical model and genetic algorithm optimization. The EV is connected to the integration bus through a bidirectional inductive wireless power transfer system (BIWPTS), which allows the EV to be charged and discharged wirelessly during the long-term parking, transient stops and movement. Accurate analytical and physics-based models for the BIWPTS are developed and utilized to forecast its performance, and novel practical limitations for the active and reactive power-flow during G2V and V2G operations are stated. A comparative and assessment analysis for the different compensation topologies in the symmetrical BIWPTS was performed based on analytical, simulation and experimental data. Also, a magnetic design optimization for the double-D power pad based on finite-element analysis is achieved. The nonlinearities in the BIWPTS due to the magnetic material and the high-frequency components are investigated rely on a physics-based co-simulation platform. Also, a novel two-layer predictive power-flow controller that manages the bidirectional power-flow between the EV and grid is developed, implemented and tested. In addition, the feasibility of deploying the quasi-dynamic wireless power transfer technology on the road to charge the EV during the transient stops at the traffic signals is proven