Vi utgår från observationer av universum och vår planet för att utveckla modeller och verktyg som möter globala utmaningar kring resurser, energiförsörjning och klimatpåverkan.
Vart är vi på väg? Var kommer vi ifrån? På vår institution söker vi svaren på de riktigt stora frågorna. I ett långt tidsperspektiv ger stjärnor och galaxers livscykler en inblick i universums, jordens och livets uppkomst – och framtid. Vi observerar också vår planet och samspelet mellan samhälle, teknik och natur för att kunna utveckla teknik, modeller och verktyg som kan möta globala utmaningar inom naturresurser, klimatpåverkan och energiförsörjning.
Observes the universe and our planet, to develop models and tools that meet global challenges regarding resources, energy supply and climate impact.
Where do we come from and where are we going? At our department we search for answers to the really big questions. In a long time perspective, the lifecycles of stars and galaxies provide an insight into the origin and future of the universe, earth and life. We also observe our planet and the interaction between society, technology and nature in order to develop technologies, models and tools that can meet global challenges regarding natural resources, climate impact and energy supply.
(2015) Fürst, Fredrik; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
This project presents a design and construction of a three-phase inverter, drive circuit and dc-link capacitor bank. The inverter should be able to supply an electrical machine with 48 V and 250 A. Initial calculations and simulations were made to get some base for the ordering of hardware. The inverter board consists of six MOSFETs in parallel for each phase and the PCB itself is made of aluminum to enable a thermal substrate technique. The inverter PCBs are mounted on an aluminum frame where liquid runs between them to cool the inverter. The drive circuit is controlled with a dSPACE system and the tests are made with a load consisting of cables and iron powder cores. Temperatures are measured with PT100 sensors for the water and an infrared camera for the surfaces. Two different MOSFETs were investigated, one with higher switching losses and one with higher conduction losses. The two inverters were tested on an RL load and the cooling system picked up around 270 W at a phase current of 150 Arms. Theoretical calculations, performed with measured parameters, represents the temperature measurements well. The thermal resistance between the case and the sink in the inverter, Rcs, is measured to around 0:15 [K=W].
(2012) Brunnsåker, Peter; Östling, Martin; Chalmers tekniska högskola / Institutionen för energi och miljö; Chalmers University of Technology / Department of Energy and Environment
Environmental safe and non-polluting methods for supporting a growing earth population with energy has never been as discussed as during the last years. This thesis is an evaluation of upgrading a concentrated solar power (CSP) plant based on the stirling dish technology with an inverter controlled generator system instead of a system locked to the grid frequency. The purpose is to investigate if the extra energy obtained economically justifies investment in a more efficient but more expensive solution. This thesis shows that by introducing an inverter controlled drive system, the resulting CSP system is more efficient during the less sunny days as well as during the morning/afternoon hours. The overall annual efficiency for a reference site in Los Angeles, California (USA) increased by 6.7% as well as giving the benefit of not needing to optimize the system for each new installation site. The extra energy produced is shown to justify an investment in an inverter-controlled variable speed drive