Odrive based electric motor dynamometer

An open source four-quadrant brushless electric motor dynamometer based on the Odrive Robotics motor controller.

Project status: On hold until the end of 2019 due to other commitments.

Features

• Designed to test motors from 50 to 2000 W over 0 to 7500 RPM with a peak braking torque of 3.5 N.m
• Different sized motors can be accommodated through the use of different absorber motors
• Can map motor efficiency and power loss for both motoring and generating (four quadrant operation)
• Can measure static torque and therefore torque constant and motor constant.
• Can measure phase inductance and resistance at room temperature and at elevated temperature
• Can measure no load maximum speed and power draw
• Capable of separating the power loss in the motor and motor controller
• Uses low cost components for current sensing (current shuts) and torque sensing (load cell)
• Breaking energy recovered and supplied to test motor in a closed loop to reduce power supply requirements

Design

The motor under test is connected by a shaft coupler directly to a D6374 sized motor which is used as an absorber. The absorber motor provides a breaking toque or driving torque when testing generating performance of the test motor. Torque is measured by a load cell which is attached to the frame of the absorber motor by a pivot arm. Power draw is estimated by current shunt and bus voltage which is monitored by a secondary microcontroller. All control is handled by the Odrive motor controller using a python script which outputs a text file with all the measurement results.

See this album for more images of the test bench.

Preliminary results

The raw data can be found here.