Three Phase AC Motor Control Project

We have done an engineering project on designing an AC synchronous three phase permanent magnet motor as a direct drive for scooters and e-bikes. The motor shown is an example and doesn't look like the one we're working on. One of our partners did most of the motor design, while our task was to devise the control hardware and software. We employed an optical position feedback system that though simple and cost efficient provides an exact and reproducible angular rotor position measurement.

The current and phase is controlled by TI's TMS320F240 processor. Preliminary test results show that the idle consumption of the motor is minimal. Eddy currents could be dramatically reduced due to the thorough motor design. The motor itself runs with very small higher torque harmonics (cogging free). The torque is high enough to be used in a gearbox-free bike or scooter with sufficient driving performance.

Comparisons with a competitor using a gearbox proves that the concept is more efficient due to the elimination of friction losses in the transmission.

The TI DSP processor provides high computational power plus a complete motor control interface, virtually eliminating the need for further hardware besides the inverter bridge. The necessary Clark-Park transformations take only a view microseconds. The complete control cycle takes 200uS only, providing a short response time and drive latency. For further information please E-mail.

Gerdes Systemtechnik
Mühlgraben 5
D-09669 Frankenberg
Germany

Phone:
Fax:

xx49-37206-6009-20
xx49-37206-6009-24