My customer is having problems running his motor down to 0.5 RPM with the DRV8308:
A couple of months ago I purchased a brushless DC motor controller eval board called the TI DRV8308EVM. I looked into the possibility of using this IC as a common controller for our pumps. It worked very well over certain ranges. However, I could not get it to work at the very low speeds that is required for our pumps, which is 0.5 RPM. If there is something that I missed as I evaluated the DRV8308, please let me know.
In general I considered the DRV8308 just right because of its SPI interface and closed-loop PWM control. But its inability to control at those low speeds I mentioned is causing us to reconsider using it. Again, please let me know if there is anything that I am missing.
Motor Parameters / 1/10th HP | |
Number of Poles | 4 |
Winding configuration | 3-Phase WYE |
Hall effect angle | 120° electrical |
Continuous Torque (Tc) | 35 oz-in |
Rated Speed @ Tc | 3500 RPM |
Rated Current @ Tc | 2.31A |
Peak Torque (Tp) | 105 oz-in |
Torque constant (Kt) | 15.62 oz-in/A |
Back EMF Constant (Ke) | 11.57 Vp/kRPM |
DC resistance (Rt) | 1.59 Ohms |
Inductance (Lt) | 4.62 mH |
Rotor Inertia (Jm) | 0.67 oz-in2 |
Thanks for you help!