Environmentally-friendly rides
The hunt is on for green and cost-effective solutions for personal transportation.
Data Respons in Lund, Sweden is assisting Höganäs in developing their Electric Drive System, thus setting a new standard for pedelecs and e-bikes up to 500W.
E-bikes are cycles equipped with an auxiliary electric motor that can exclusively be propelled by that motor. The motor output of an e-bike is activated and controlled by using a throttle or button. Another type of electric bikes is Pedelecs (Pedal Electric Cycles). Pedelecs are equipped with a motor that helps the cyclist depending on how much force that is put on the pedals and is measured by means of a torque and/or speed sensor. There are, however, restrictions in terms of nominal motor power and maximum speed, for Europe typically 250W and 25 km/h.
Various light electric vehicles (LEV) are already providing environmentally friendly and sustainable alternatives to conventional ways of transportation; however, there are still challenges around improving battery life, system quality as well as the interaction between driver and system.
Thanks to the combination of a revolutionary transverse flux direct drive hub motor, dedicated control and a good HMI unit, the e-drive system offers a reliable, smooth and silent riding experience, without vibrations at low speed.
The E-Drive System
The system is designed to be powered by36or 48V batteries. The exceptional low-speed torque (up to 50 Nm) allows fast acceleration, even at high loads. The gearless motor power is provided directly to the rear wheel, resulting in an outstanding system efficiency that increases the driving range by at least 15% in comparison with traditional systems with geared motors. Moreover, geared motors are noisy and do not offer possibility for regenerative braking due to their freewheel.
The 3-phase, 50-pole design of the Höganäs motor consists of an inner stator and an outer rotor carrying the magnets and soft magnetic pole pieces. Each phase consists of two pressed Somaloy® stators on either side of a simple hoop coil. With this unique topology, torque can be increased by simply increasing the pole number unlike in a conventional wound radial machine. For this reason, the Electric Drive System is well suited for torque dense, low-speed applications such as electric bicycles.
Data Respons’ contribution
Data Respons comprehensive and extensive knowledge on low level motor control software (which carries out the high performance and smooth ride of the motor) was crucial to Höganäs.
Data Respons was also responsible for developing the HMI unit that is placed on the bikes handlebar, a safety-critical component. The electric bike must work in tough outdoor conditions at both low and high temperatures. The HMI display unit has a Cortex M3 MCU running FreeRTOS and has safe real-time communication with the motor control unit over a wired serial bus. The display automatically adjusts in order to get good and safe readability.
The proprietary communication protocol was developed in tight cooperation with Höganäs whose particular challenge was to develop a safe and cost-effective solution as the product is intended for the consumer market. Data Respons worked closely with partner Zenit Design Group in Malmö on the industrial and mechanical design.
