Systemutformning av autonom batteridriven traktor inom lantbruket
In this study, data from different studies were used to find how much energy that a conventional tractor required per hectare when it was performing different operations on a field. Data for operation speed and power demand were taken from an earlier study for each task of the tractor model Valtr...
| Autor principal: | |
|---|---|
| Formato: | L3 |
| Lenguaje: | sueco Inglés |
| Publicado: |
SLU/Dept. of Energy and Technology
2018
|
| Materias: |
| Sumario: | In this study, data from different studies were used to find how much energy
that a conventional tractor required per hectare when it was performing different
operations on a field. Data for operation speed and power demand
were taken from an earlier study for each task of the tractor model Valtra
6600. In this report, the operation speed for each task on the field were simulated
in Excel together with a given electrical motor, a battery and a
charger. This was done in order to find what affected the working time for
an autonomous battery powered tractor. Two scenarios were studied in Excel;
how the distance to the charger, and different charging speeds affected
the working hours in order to operate a 200-hectare farm.
The size of the battery affected the results most when the distance between
the field and the charger was studied. The system design was in need of a
larger battery size when the distance to the charger was 10 km or more.
With a smaller distance, a smaller battery was required to reach valid results.
Larger power of the charger means not only lower charging time of
the battery. The results also showed that if the system configuration had a
larger charging power, the working days of the tractor did not decrease significantly
by larger battery size. In other words, the working hours of the
tractor were more affected by larger battery size for a low-powered charger
than for a high-powered charger. In this study, a high-powered charger was
set to 100 kW to decrease the purchasing cost.
Considering the high cost and weight of the battery, the smallest battery size
as possible was chosen, without increasing the working time on the field too
much. A battery of 100 kWh was chosen since the results did not improve
generally by installing a larger battery size. The electric synchronous permanent
magnet motor was chosen to the system configuration, due to its
normally high-power density and high efficiency. The power of the motor
was set to 70 kW, since a smaller motor has lower weight and can be powered
by less energy per hour compared to a larger motor.
With a system configuration of a high-powered charger of 100 kW, a high
energy density battery of 100 kWh and one synchronous permanent magnet
motor of 70 kW, the working time for the autonomous battery-powered tractor
to perform different operations on a field was calculated to 63 days. This
included field operation, transport between the charger and the field and
charging time. Assuming the tractor was working 24 h a day at a 200-hectare
farm and that the speed of the tractor on the road between the field and
the charger was 30 km/h. The cost and the weight of the system configuration
was calculated to 587 000 SEK and 646 kg. Considering maintenance
and whether variations, in reality the autonomous tractor would have needed
more time than 63 days of working the farm. |
|---|