The most important challenge in this application was optimising the startup sequence for the compressor. As many people are aware this is often the biggest challenge when using sensorless brushless DC motors and it is made even more difficult when working in applications where starting under load is also a requirement. That said, our technical team have put a lot of time into optimising and developing successful start up procedures for such applications.
This has been achieved through a combination of carefully programmed acceleration curves and optimising the initial forced commutation for each specific motor. We often have to request a sample of the exact motor that you are wanting to use in order to be able to set this up.
By implementing these various procedures we were able to improve on the performance of the previous ESC considerably and add a range of additional control options.