Effects of electronically commutated motors used in passenger cabin air conditioning on low voltage network of a cruise ship
Kivimäki, Juha (2016)
Kivimäki, Juha
2016
Sähkötekniikan koulutusohjelma
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2016-11-09
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201610124589
https://urn.fi/URN:NBN:fi:tty-201610124589
Tiivistelmä
In this thesis the target was to explore the cabin air conditioning system and especially then fan solution. The fan motor is an electronically commutated (EC) motor. The idea is to clarify the harmonic phenomenon and how the EC-motors affect to the electricity quality. First it is convenient to introduce the electricity network of a passenger cruise ship and give a basic understanding of the components included in the network. There are both medium voltage and low voltage networks in the ship. The used electricity network is modified from a Mein Schiff –ship with little modifications so that the important key figures are not compromised.
The EC-motor construction was introduced before the effects to ease the understanding why EC-motor produces harmonic currents and voltages which create harmonic distortion. The theory about harmonics is presented to the extent that is necessary for the the-sis; sources of harmonics, effects of harmonics and different solution for harmonic mitigation. After the electricity network and harmonics are presented the focus is on the information of the certain EC-motor type that is installed in the cabin air conditioning module. An active power factor correction unit is used in series with the EC-motor and the goal is to figure out if the power factor correction is needed in the system. This was done with both analyzing the theoretical side of the motor and then with practical measurements on the sea trial of the ship.
The solution was that the power factor correction is not needed due the low harmonic currents and low electric power. This was also ensured by comparing total harmonic distortion measurements between the previous ship and the present ship because in the previous there was no power factor correction unit with the EC-motor. However the power factor correction improves the power factor almost by 0,5 (0,53 → 0,99) which means also better energy efficiency. To decide whether the power factor correction unit is needed one must evaluate the cost of the installation and the cost of the electrical energy.
The EC-motor construction was introduced before the effects to ease the understanding why EC-motor produces harmonic currents and voltages which create harmonic distortion. The theory about harmonics is presented to the extent that is necessary for the the-sis; sources of harmonics, effects of harmonics and different solution for harmonic mitigation. After the electricity network and harmonics are presented the focus is on the information of the certain EC-motor type that is installed in the cabin air conditioning module. An active power factor correction unit is used in series with the EC-motor and the goal is to figure out if the power factor correction is needed in the system. This was done with both analyzing the theoretical side of the motor and then with practical measurements on the sea trial of the ship.
The solution was that the power factor correction is not needed due the low harmonic currents and low electric power. This was also ensured by comparing total harmonic distortion measurements between the previous ship and the present ship because in the previous there was no power factor correction unit with the EC-motor. However the power factor correction improves the power factor almost by 0,5 (0,53 → 0,99) which means also better energy efficiency. To decide whether the power factor correction unit is needed one must evaluate the cost of the installation and the cost of the electrical energy.