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Technical Tuesday: Motor Control of the Delta XE
Our electric superbikes differ in many ways from traditional fuel-powered motorcycles with the obvious change being the power delivery system, namely the electric motor and battery. It is not as simple as swapping the fuel tank and engine for a battery and electric motor. It also introduces many new components. One of these new components is the motor controller. It acts as a bridge between the battery and the electromotor, ensuring the power of the battery is correctly applied to the electromotor. The current from the battery is a direct current (DC), while the electromotor uses a 3-phase alternating current (AC). As a result, the battery power must be altered before it can be received by the electric motor. 
The motor controller contains a 3-phase power inverter, a circuitry designed to invert DC to AC power using a series of transistors. In the Deltas motor controller, the Cascadia PM 150 DZR, the transistors operate at a rapid pace, switching on and off at a rate of 12 000 Hz. It produces three alternating currents shaped like a sinusoid. The electric motor contains three pairs of coil windings, each of which corresponds to one of the currents coming out of the motor controller. This is part is the stator, the static part of the electric motor. By correctly applying the currents, a rotating magnetic field is produced by the stator. The rotor, the revolving part of the motor, will rotate together with the magnetic field as a result. This rotating motion is the power that comes out of the motor, which is subsequently fed into the gearbox and ultimately transmitted to the rear wheel.
The Cascadia is not simply an inverter. It contains many features which allow us to get as much power out of the motor as possible. Because track racing requires very different power delivery throughout corners and straights, the torque and speed the motor needs to supply is rather versatile. To get the best performance out of the motor, a control system is applied to the inverter. The control system calculates the currents and voltages it needs to supply to the motor to get the power the user desires. The Cascadia utilizes a feedforward control system using a lookup table. Essentially, a large table is constructed by evaluating the motor behaviour at various currents and torques. By finding the optimal currents for a certain torque value, we can ensure the superbike is as fast as possible.
We are currently constructing the lookup table on our dynamometer. Once it is finished, the motor controller is optimized to supply the ideal power on all ranges the motor is designed for. Subsequently, the Delta can have the maximum amount of power available in all stages of a hotlap.
– Bram Harbers
Team Interview: Ralph Brantjes
Hi, I’m Ralph. I’m the current external relations and finance of Electric Superbike Twente. My job is to get into contact and maintain contact with partners. Next to that, I’m also in charge of the finances. This means I make sure that the invoices are paid and that the budget correct. I am doing a gap year from my Masters electrical engineering with the robotics and mechatronics specialization.
What is your opinion on electric racing?
I think electric racing is great. It enables faster acceleration and it is just as exciting as other types of racing except that it is more sustainable. The only downside is the different engine noise. However, this means that electrical vehicles comply to sound regulations meaning that races can be held year round without disturbing the environment. Electric racing also means being at the forefront of new technical developments that will trickle down to normal vehicles in the future.
Name a partner you personally value a lot.
One of the partners I value a lot is Ten Kate Racing Products. That is because they are one of our first partners and they have helped us a lot throughout the years. Without them it would have been a lot harder to be able to get all the parts for a fully fledged motorbike.
What is the most fun thing to do as the External Relations of EST?
For me, it is visiting the broad spectrum of different companies. It is really fun to see the different environments and atmospheres of all our partners.
What is the funniest encounter while being part of EST?
I don’t really have a specific encounter that was funny but within the team the atmosphere is great. Besides working hard we also have a lots of fun and many inside jokes and funny moments. I would say that the whole team is what really makes me happy.
What is a company you would like to become partners with? And Why?
Red Bull would be a company I would really like as our partner. The reason behind this is because I am a big Formula 1 fan and so having a company that is a competitor in the highest racing class would be great. Next to that, they have a certain daring and extreme sports image to them which would fit the fastest electrical superbike very well.