Ripple Suppression in High-Speed BLDC Motors Used in General Motion Control
The technology
The Canadian Space Agency (CSA) innovation provides a method for commutating brushless DC (BLDC) motors, eliminating the torque ripple in motors operating at high rotor speeds. The technology utilizes feedbacks from the rotor's angular position and velocity to shape the motor's phase currents, taking into account the driver/amplifier finite bandwidth dynamics. This results in the elimination of torque ripple at all rotor velocities, while simultaneously minimizing power losses.
The CSA technology represents a new method of controlling BLDC motors. In providing a control signal the method takes into account not only the feedback information about the state of the rotor (its position with respect to the stator and its velocity), but also the dynamic characteristics of the amplifier, i.e., how the amplifier distorts signals received from the commutator. This information is used to form the control signal in such a manner as to eliminate the pulsation of the torque when the amplified (and distorted as a result) signal is delivered to the coils of the stator.
The technology represents a modification of the commutator law of BLDC motors based on Fourier coefficients in order to eliminate the velocity-induced torque ripple at any given velocity. This is made possible by expressing the motor's current waveform as a function of not only the rotor angle but also the velocity and taking into account the driver/amplifier's finite bandwidth dynamics in the control design.
Commercial potential
The CSA innovation provides potential for a manufacturer to substantially reduce the cost of high-performance BLDC motors and motor drives in motion control systems designed for applications requiring high rotor speed and high precision. The technology's application of more-complex control algorithms (i.e., software) enables the use of BLDC motors and drives of simpler (less expensive) construction, replacing expensive multi-pole motors.
This CSA control technology provides the capability to turn an ordinary, three-pole brushless motor into a high-performance motor with minimum pulsation for precise applications such as flywheels and gyroscopes for spacecraft. The CSA technology also reduces the weight and volume, which are always an issue for space (and perhaps other) applications.
The business opportunity
The technology is available for license. This CSA control technology will be of interest to companies that develop and manufacture BLDC motion controllers, drives and motors. Market opportunities for the CSA technology are in industries that have a need for speed and precision simultaneously. There are well-established markets for motion control systems that require rapid, accurate positioning.
Technology transfer details
A commercialization license for this technology is available.
The business opportunity may be referred to by its CSA case ID: 51072
Publications
- Aghili, F., "Ripple Suppression of BLDC Motors with Finite Driver/Amplifer Bandwidth at High Velocity", Institute of Electrical and Electronics Engineers (IEEE), IEEE Transactions on Control Systems Technology, Vol. 19, No.2, pp.391-397, .
- Aghili, F., "Adaptive Reshaping of Excitation Currents for Accurate Torque Control of Brushless Motors", Institute of Electrical and Electronics Engineers (IEEE), IEEE Transactions on Control System Technologies, Vol. 16, No.2, pp.356-364, .
Patents
- Canada
- Number: 2769084
- Status: Patent Granted
- Source: Canadian Intellectual Property Office (CIPO)
- United States
- Number: 8,766,578
- Status: Patent Granted
- Source: United States Patent and Trademark Office (USPTO)