With fast development of semiconductor industry, the transistors in microprocessors increase dramatically, which follows the Moore’s law. As a result, the operating voltages of the future microprocessors follow the trend of decreasing (sub 1V) while the demanding currents increase (higher than 100A). Furthermore, the high slew rates during the transient will reach 1200 A/us. All these impose a serious challenge on a Voltage Regulator (VR) or Voltage Regulator Module (VRM). In order to meet requirements of the next generation microprocessors, four new ideas are proposed in this thesis. The first contribution is an accurate analytical loss model of a power MOSFET with a Current-Source Driver (CSD). The impact of the parasitic components is investigated. Based on the proposed loss model, a general method to optimize the CSD is presented. With the proposed optimization method, the CSD improves the efficiency from 79.4% using the conventional voltage source driver to 83.6% at 12V input, 1.5V/30A output and 1MHz. The second contribution is a new continuous CSD for a synchronous buck converter. The proposed CSD is able to drive the control and Synchronous Rectifier (SR) MOSFETs independently with different drive currents enabling optimal design. At 12V input, 1.5 V/30A output and 1MHz, the proposed CSD improves the efficiency from 79.4% using a conventional voltage source driver to 83.9%. The third contribution is a new discontinuous CSD. The most important advantage of the new CSD is the small inductance (typically, 20nH at 1MHz switching frequency). A hybrid gate drive scheme for a synchronous buck converter is also proposed. The idea of the hybrid gate driver scheme is to use the CSD to achieve switching loss reduction for the control MOSFET, while use the conventional voltage source driver for the SR. At 12V input, 1.3V/25A output and 1MHz, the proposed CSD improves the efficiency from 80.7% using the voltage source driver to 85.4%. The final contribution is new self-driven zero-voltage-switching (ZVS) non-isolated full-bridge converters for 12V input VRM applications. The proposed converter achieves the duty cycle extension, ZVS operation and SRs gate energy recovery. At 12V input, 1.3V output and 1MHz, the proposed converter improves the efficiency from 80.7% using the buck converter to 83.6% at 50A. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2009-04-23 08:59:12.699

År 2012 gick ca 30 % av den totala energianvändningen till uppvärmning av bostäder och lokaler. Av den utgör uppvärmning av flerbostadshus och lokaler 60 % (79,5 TWh). Det finns därmed stor potential att minska energianvändningen inom bostadssektorn. En del i effektiviseringsarbetet är att se över regleringen av utrustningen som styr uppvärmningssystemen i bostäderna. Dagens reglering innefattar oftast en styrning som är direkt kopplad till utomhustemperaturen. Denna form av reglering lämpar sig bäst till system där ändring av tillstånd kan ske fort. När det gäller bostäder med hög massa tar det däremot tid innan en ändring får effekt. I vissa fall kan trögheten vara bortåt ett dygn för bostäder med hög intern massa. Ett alternativt till dagens enkla metoder är den så kallade MPC-regulatorn som står för Model Predictive Control. MPC är en reglermetod som kan ta hänsyn till trögheten och dynamiken hos byggnader. MPC-regulatorn arbetar dessutom proaktiv snarare än retroaktivt vilket de flesta av dagens reglermetoder gör. Ett problem med MPC-regulatorn är att den kräver stora beräkningsresurser samt energiteknisk kunskap om byggnaden där den ska implementeras. Detta gör att den har haft svårt att slå igenom. Syftet med examensarbetet var därför att konstruera en enkel MPC-regulator och utvärdera dess funktion. Detta gjordes genom att konstruera en bänktestmodell som utvärderade funktionen av regulatorn. Utöver att konstruera en simpel MPC-regulator har en studie gjorts på hur den nuvarande reglermetoden kan energieffektiviseras utan att behöva investera i ny utrustning. Målet var att få en jämn inomhustemperatur och förbättra driftsekonomin för byggnaden som studerades. Studien har genomförts hos Karlstads Bostads Aktiebolag (KBAB) som förvaltar och äger 7300 lägenheter i Karlstad. Studien presenterar ett antal enkla MPC-regulatorer som kan användas för att uppnå jämnare inomhustemperatur och bättre driftsekonomi. Det bedöms dock att den MPC-regulatorn som endast tar hänsyn till utetemperaturen i sin prediktering är den mest lämpliga. MPC-regulatorn har potential att sänka värmebehovet med 3,12 MWh/år (-4 %) och minska inomhustemperaturens variationer med 96 %. Årsmedeltemperaturen skulle hamna på 21,1 °C och energiförbrukningen på 113 kWh/m2. Studien presenterar dessutom ett alternativ till dagens reglermetod som inte kräver några extra resurser eller investeringskostnader. Den har potential att sänka värmebehovet med 8,3 MWh/år (-10 %) och minska inomhustemperaturens variationer med 65 %. Energiförbrukningen skulle då bli 106 kWh/m2 för byggnaden. / In 2012, 30% of the total energy consumption was used by apartments and buildings. Heating of apartment buildings and commercial buildings represents 60% (79.5 TWh) of that energy consumption. There is thus great potential for reducing energy use in the residential sector. Part of the overall efficiency work is to review the control of heating systems. Today's control often involves simple on / off systems where an upper and lower limit controls when to start and stop a process. This form of control is therefore best suited to systems where the change of state occurs quickly. When it comes to homes with high mass however, it takes time before a change takes effect. In some cases, it can take up to 24h before a change is noticed for buildings with high thermal inertia. An alternative to the traditional temperature based control is the so-called MPC controller which stands for Model Predictive Control. MPC is a control method that can take into account the thermal inertia and the dynamics of buildings. MPC controller also controls the system proactive rather than retroactive, which is the technique most of current control methods use. One problem with the MPC controller thou is that it requires large computational resources and technical knowledge of the building where it will be implemented. The aim of the thesis was to design a simple MPC controller and evaluate its performance. This was done by constructing a bench test model that can evaluate the function of the MPC controller. In addition to constructing a simple MPC-controller, a study has been done on how the current control method can be more energy efficient without having to invest in new equipment. The goal was to reduce the variations in indoor temperature and improve operating economics of the building. The study was conducted at Karlstad Bostads Aktiebolag (KBAB) that owns and manages 7,300 apartments in Karlstad. The Bench test model calculated indoor temperature using the weather conditions as solar radiation, cloud cover, outside temperature and wind speed. The study presents a number of simple MPC controllers that can be used to minimize indoor temperature variations and improving operating economy. It is estimated, however, that the MPC controller that only takes into account the outside temperature in its prediction is the most appropriate. The MPC controller has the potential to reduce heating requirements by 3.12 MWh (-4%) and reduce indoor temperature variations with 96%. The mean annual temperature would be 21.1 ° C and the energy consumption 113 kWh/m2 for the building. The study also presents an alternative to current control method that does not require any additional resources or investments. It has the potential to reduce heating requirements by 8.3 MWh (10%) and reduce indoor temperature variations by 65%. The energy consumption would then be 106 kWh/m2.

Softwood cuttings of Euonymus alatus and the cultivar Rudy Haag, a nearly seedless cultivar, were taken in Kentucky on two cutting dates. E. alatus Rudy Haag cuttings taken in mid-May, untreated or treated with 1000 - 3000 ppm IBA, produced many roots on a high percentage of cuttings. Post-rooting shoot growth was reduced for the species with cuttings taken in June. Rudy Haag produced new growth on cuttings taken in May with no IBA treatment. Transplanting resulted in a decrease in new growth. Liner plants of E. alatus Compactus and Rudy Haag were planted into 1 and 3 gallon containers of two different types, conventional black plastic and root training. A second experiment exposed plants to two levels of supplemental fertilizer in addition to slow release. A subsample was sprayed with Fascination (BA + GA4+7) at 1500 ppm in late July. No difference was seen in above-ground growth due to container type or supplemental fertilizer. A change in root morphology is seen with root trainers. Three gallon containers produced a larger plant than one gallon containers. Rudy Haag sprayed with Fascination were greater in size and branch number than those not sprayed.

Methoprene is a Juvenile Hormone (JH) analogue commonly used for the control of mosquito larvae. When applied to a mosquito breeding site, methoprene enters the haemolymph, where it mimics the function of JH and interferes with normal metamorphosis, resulting in larval mortality. Methoprene is commonly used for the control of larvae and has not been used as an adulticide, due to an absence of acute effects. This study evaluated possible chronic effects caused by the exposure of adult Aedes mosquitoes to methoprene. Methoprene was applied, in both technical grade and the commercially available Altosid®, topically to adults through droplet application on the abdomen and as a spray application. Mosquitoes were examined for treatment effects on ovary development, adult male and female mortality, and fecundity. The results demonstrate that relatively high doses are required to affect adult survivorship. In contrast, significant impacts on both fecundity and egg hatch were observed for females treated at the lower dosages. I discuss the results in relation to autocidal strategies for mosquito control in which the release of fecund females is to be avoided.

A servo system intended to steer antennas on board ships is designed, built and tested. It uses a Brushless Direct Current (BLDC) motor with an encoder to keep track of its position, and Field Oriented Control (FOC) implemented on Toshibas microprocessor TMPM373 in order to control the current flowing to the motor. The servo system will be connected in cascade to another already existing servo system and controlled with two input signals. The first signal determines if the antenna axis should rotate clockwise or counter clockwise. The second signal is a stream of pulses, where each pulse means that the motor should move one encoder point. A printed circuit board is designed and built to complete these tasks. A proportional-integral regulator is used to control the position of the motor, using the position error as the controller input. The servo system is tested. The performance of the resulting servo system is sufficient to satisfy the required position error limit of 0.5 degrees. In order to reduce the periodic disturbances presented in the system in experiments, Iterative Learning Control (ILC) is implemented. It is shown that using ILC further decreases the position error.

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Feb. 6, 2008). Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

Thesis (Ph. D.)--Cornell University, May, 1997. / Includes bibliographical references (leaves 170-181).