Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Low cost, reliable and durable solutions are required in all industries. In automotive industry, BLDC (Brushless Direct Current) motors are widely used due to its advantages over brushed DC motors, which also brings more complex commutation schemes and increased development cost.
Despite the fact, BLDC motors require low maintenance and provide reliable results in compare with brushed DC motors, the cost of development of control stage and required hardware topology has been a competence area. The requirements of the application tailor the required hardware topology and control strategy. In this thesis, BLDC motor commutation control hardware topologies to implement a BLDC motor based air throttle control circuit, power dissipation and EMC considerations are addressed.
BLDC motor control of a throttle were chosen as a test case due to Scania requirements. An air throttle adjusts the air intake going to a combustion engine, thus directly e ecting the performance. The better controlling the throttle means, providing reliable results with lower consumption of energy. The throttle chosen is an intelligent self positioning unit being bought from a sub-supplier and Scania steers the control by means of an angle position reference sent via CAN (Controller Area Network) bus. The sub-supplier solution results in lack of exibility in software and hardware implementation and lacking possible customization improvements.
A customized hardware solution was implemented to question whether a custom hardware implementation and a control strategy planned by Scania can resolve in less power consumption. In addition, what is required to make the throttle unit better should be reected. For this purpose,a customized commutation control circuit was built and a benchmarking in compare with the original sub-supplier solution were done to enable comparison and discussion on possible improvements.
One unit of sub-supplier and one unit of customized hardware were benchmarked with respect to heat dissipation, current consumption at the time angle is settled and EMI (Electromagnetic Interference). The results showed that the given Scania control strategy may yield in decreased current consumption, thus reduced heat dissipation.
Despite the fact the results are prospective, from a scientic point of view, a comprehensive long term benchmarking should be done with multiple units. The outcomes of this project are a hardware platform which can be used as a development platform to further enable comparison and development, partially proven Scania control strategy to reduce dissipation and enabling cumulative future work in form of diagnostics.
2014. , 103 p.