BLDC control problem

[dingding]

I use 56F807evm to control bldc motor. The problem is sometimes motor cannot start, even given enough output. This problem sometimes is serious, sometimes is not so serious, maybe once in 200times starting. It is random. But I think it is something wrong in my software, maybe configuring the register. I write my code by myself use c, not produce code by processor expert. The power module is base on an IPM. When abnormal starting, the output is correct. If you push the rotor lightly, even touch it, it can start.

Thank you very much!

[glork]

Hello dingding.
You didn't say if the motor ran correctly after you had to manually start it (i.e. touch it, etc.). If it does then perhaps your problem is that your starting power setting is just marginally too small to guarantee that the motor will start.

The 3 main factors that determine the energy necessary to start the motor are:
1. The inertial mass of the rotor assembly
2. Whatever starting load (if any) you have coupled to the shaft
3. The starting friction (stiction) of the rotor bearings

Your starting power setting must provide enough energy to the windings to overcome this.

Or you could have some other problem.
ron