Papers by Alex Van den Bossche
Brazilian Power Electronics Conference, 2005
IEEE Transactions on Power Systems, 2005
In this letter, it is shown that the positive-and negativesequence components of a three-phase, s... more In this letter, it is shown that the positive-and negativesequence components of a three-phase, sinusoidal and unbalanced voltage system can be calculated exactly without the application of the Fortescue transformations in the complex plane, while only the root mean square (RMS) line-to-line voltages are required, and without having to measure the phase relationships between these voltages. This results in a convenient procedure to assess voltage unbalance in the field. The phase relationships between the sequence and line components can also be calculated. Moreover, if the RMS values of the line-to-neutral voltages are known, the zero-sequence component can be calculated exactly as well, again, without the application of complex mathematics.
Climate change, sea level rise and pollution are actual concerns. However, most of people are not... more Climate change, sea level rise and pollution are actual concerns. However, most of people are not aware how much things have changed at the North Pole region, where the ice volume probably first disappears in the month of September in the years 2020-2025 and 50% of the year around 2040. The solutions are to drastically reduce CO2 and CH4 emissions. The Greenland ice melted in 2016 at 1.5 m/year but this rate can increase up to 5-10 meter/year. The corresponding ocean level increase may be up to 3 m/century. Methane is the main local reason as it disappears only slowly at North Pole. Other regions get too hot. The solution is a more electric, renewable based society. Drastic solutions are ultralight electric vehicles instead of the actual heavy ones, also wearable cooling or warming close to persons, rather than cooling or heating of large rooms. Power electronics is the key solution to control the generation and the use of alternative energy.
Rolling and drag losses are important in electric vehicles. There is a compromise between price, ... more Rolling and drag losses are important in electric vehicles. There is a compromise between price, lifetime, reliability and rolling resistance for tires. In electric bicycles improving the drag would end up in faired bicycles and velomobiles. Still future improvements can be expected from the efficiency of motors, converters and gears. Improving efficiency reduces the cost of the battery which might be typically 60% of the vehicle cost.
Rolling losses get more important than drag losses around cities with low speed and traffic jam. ... more Rolling losses get more important than drag losses around cities with low speed and traffic jam. The weight of cars did increase a lot in the last 50 years, but the tendency is down again. The consumption of auxiliaries did increase also but LEDs, improved fans, could reverse the tendency. Knowing the details of rolling, drag, acceleration, altitude change and auxiliaries, the mechanical needs get predictable for electric cars. Knowing all this, with a conventional car, while using 19 tricks, the NEDC listed consumption can be reached in practice. Electric vehicles of less than 150 kg for two persons may be the solution for the future.
Electric cars have the disadvantage of a limited range, and drivers may experience a range anxiet... more Electric cars have the disadvantage of a limited range, and drivers may experience a range anxiety. This range anxiety can be solved by adding a range extender. But, the range extender should be light so as not to significantly increase the weight of the original vehicle. In urban areas with dense traffic (usually developing countries), the average speed around cities is typically lower than 50km/h. This means, the rolling resistance losses are more important than aerodynamic losses, and a weight reduction results in a bigger electrical range. Therefore, smaller and lighter range extenders are of much interest. The contribution of this paper is to indicate the possibility of range extenders with less than 25 kg with a capacity of 150 to 200 cc to suit a condition where weight counts. In this paper, the cost, environmental and grid impacts of going electric are also discussed. The effect of high altitude and driving style on the performance of an electric vehicle is assessed. The challenges and opportunities of vehicle electrification between countries with decarbonated power generation and fossil fuel dominated power generation are highlighted. Throughout the article, the case of Ethiopia is taken as an example.
International Conference on Optimization of Electrical and Electronic Equipment, 2004
Active and Passive Electronic Components, 2017
A simple half-bridge, galvanic separated power supply which can be short circuit proof is propose... more A simple half-bridge, galvanic separated power supply which can be short circuit proof is proposed for gate driver local supplies. The supply is made while hacking a common mode type filter as a transformer, as the transformer shows a good insulation, it has a very low parasitic capacitance between primary and secondary coils, and it is cost-effective. Very low standby losses were observed during lab experiments. This makes it compatible with energy efficient drives and solar inverters.
European Conference on Power Electronics and Applications, 1997
Maximizing the efficiency in transport vehicles will be a necessity. This may be realized by intr... more Maximizing the efficiency in transport vehicles will be a necessity. This may be realized by introducing a power electronic conversion between the Internal Combustion Engine (ICE) and the wheels. Hence the ICE may be used at its maximal efficiency point. One still can choose the kind of fuel: liquid or gas hydrocarbons, hydrogen, alcohol. The ICE delivers electrical power by means of a high efficiency generator and rectifier Further on one can recover electrical energy from the exhaust thermal power by means of a bottom cycle. A solution is to use an organic rankine cycle for this. The motion itself is done by high efficiency converters and permanent magnet motors. One can reduce gear losses while using direct drive wheel motors. In ships one can also optimise the propeller and the number of propellers.
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Papers by Alex Van den Bossche