Low-speed Motor Control Solution - ZeST algorithm

[MDani]

Hello ST,

I’m a motor control fan and developed a few motor controllers in the past years for myself. I always worked with TI MCU’s because I liked their sensorless solution for PMSM control. At low speed the torque generation was not bad but at zero speed, there were some problems. I always started with HALL sensors and at a certain speed I switched to sensorless FOC.

At the moment I’m building a 300A 100V motor controller for my master thesis and I wanted to use a sensored solution because of the startup problems with sensorless solutions. Then I saw your ZEST algorithm, which looks very interesting.

Now I’m wondering if the ZEST algorithm could solve these startup problems, what do you think?

Can I replace the encoder with ZEST without having any problems at zero speed?

I’m using a 20kW BLDC motor which is inside a buggy car.

Best Regards,
Daniel

[Gael A]

Hello MDani,

Unfortunately, the ZeST algorithm is only available for selected customers, so you won't be able to try that out for now. However, we also provide the HSO, on which the ZeST is based, that already tackles many low speed issues, such as full torque start-up. I believe the HSO will be enough for your application, and it is freely available on our MCSDK (6.3.0).

All the information you need both for HSO and ZeST can be found on our STM32 ZeST Page.

 

[MDani]

Hello Gael A,

thank you for you answer and sry, I didn't see that. Is it possible to say when ZeST is available for everyone?

In this case I think I will use encoder. I tried several sensorless algorithms in the past, some worked not bad, but none of them was able to get a really good performance at zero speed.

My professor said, he does not think there is any sensorless solution for zero speed without having a sailent motor, but I wanted to give it a try.

I will implement everything what is needed for sensorless FOC on my PCB, so I can test ZeST, when it is available.

Best regards,
Daniel

[Gael A]

Hello MDani,

Unfortunately, there is no ZeST public release scheduled any time soon. If you really want to see the algorithm in action, I guess you could try going to tech fairs such as Embedded World or CES, as we are regularly showcasing the algorithm on our booths.
However, I really recommend you to try out the HSO algorithm, which already behaves really nicely at low speeds.

On a different note, let me clarify that the ZeST algorithm is able to run any type of motor, even the none salient ones.