Lightweight Electric/Hybrid Vehicle Design

16 Lightweight Electric/Hybrid Vehicle Design
piston engines in terms of performance and cost there will be no significant competition, hence no
major market share. Polaron are putting their money on group B. What is clear is that the economics
will come right at lower powers first, then work upwards. Another fact is that a market needs to be
established before custom designs can be justified and the most immediate need is for conversion
technology for existing vehicle platforms.
1.3.2 BRUSHED DC MOTOR
This consists of a stationary field system and rotating armature/brushgear commutation system.
The field can be series or shunt wound depending on the required characteristics. The technology
is well established with more than a century and half of development. The main problem is one of
weight compared with alternative technologies, consequently Polaron believe DC is best at lower
powers overall, due to the built-in commutation scheme. As the power level rises many problems
become significant: commutation limited to 200 Hz for high speed operation; problems with
commutator contamination; significant levels of RF interference; brush life limitations and cooling/
insulation life limitations. Polaron’s Nelco division has made these machines for many years and
Face commutator
1.
TORQUE Nm
90
80
70
60
50
40
30
20
10
A
82.5 Nm
65% 75%
Fig. 1.14 Efficiency map and Gemini motor.
85%
1000 2000 3000 4000 5000
NEXUS GEMINI
22 kW
87%
89%
A
Face commutator
2.