Throughout 2016, Monash Motorsport’s electric drivetrain team has been carefully choosing the perfect combination of powertrain components to maximise the potential of our very first electric car.
Finally, in the first week of October, we successfully spun our Emrax 228, permanent magnet motor for the very first time. This was welcome confirmation that our hard work and research for the past year had paid off and signified a real milestone in the realisation of M17-E.
Since then, our chosen design has been put through its paces on a test rig developed to validate the capabilities of our hardware, and to bring our simulated data into the real world. The physical structure is made up of a steel base and mounting plate and incorporates a detachable drive shaft for attaching varying loads. Focused around a 228mm diameter electric motor, the setup is powered by a three phase inverter unit that is fed from 500V of DC power. The whole system is controlled by our own custom designed ECU and is capable of producing up to 134 horsepower and 240 Nm of torque.
Having an independent test rig provides us the opportunity to experiment with control parameters and help find our limiting factors in a controlled environment. One such parameter is the thermal efficiency of the system. Our setup allows us to monitor the temperatures of the different components, and design a cooling system that will maximize both efficiency and performance of the system.
There are many safety precautions involved with an electric car which require an isolated test setup to introduce the targeted fault conditions. Many of the safety devices we develop ourselves, which can be quickly tested and reviewed before making it onto the car. The purpose of these devices can range from insulation monitoring to input plausibility.
To date, the process has proven to be a huge success and has given us a unique insight into the intricate details of an electrical powertrain design. In the coming months, the team will attach this setup to a dynamometer and begin to really explore the limits of our system’s power, and the potential that we hope to bring to the track at Formula SAE-A in December.
– Tim Murphy (Electric Drivetrain)