Circuit Review of BLDC Motor Controller

[brickle]

Hi!

Are there some experts who would like to Review my BLDC Motor Controller Circuit?

You can find it on **broken link removed**

I would be grateful about any comments!

BR,
Florian

 

[Electro nS]

i donot consider myself as an expert , but i have seen and tried a lot of circuits with power mosfets . so my suggestions :

1- sheet 5/6/7 : add 10k resistor from pin 2-3 of halfbridge driver to gnd (parallel to 10p capacitor , by the way what did you add this component ??) .. this resistor will make sure that the driver input are held low when micro is powering up or pin damage.
2- sheet 5/6/7 : add also 10k resitor from Ho to VS and another resistor from Lo to GND of half brdige driver . this resistor will keep the mosfets off if the driver is damaged of made an undetermined output for some reason !! extermely important.
3- sheet 5/6/7 : add 100nF or 1uF capacitor from VDD to VSS close to halfbridge driver . important
4- sheet 5/6/7 : suggestion of replacing the OPamp current sensing circuitry by a ACS714(SMD) or ACS758 (through hole)current sensor .
5- would appreciate some documentation on parts and why they were added (protection , essential , optional ) so we can help more , because i cannot check datasheets and parts of all ICS and try suggestions for all .

hope that helps . and please feel free to share your results and initial testing results , good luck in that

 

[brickle]

Thank you very much for the fast response, you mentioned very good and important points!

I added several notes in the schematic, explaining the functions of the components.

The reason for the 10pF Caps at the gate driver inputs is simply to form an RC filter to prevent faulty input signals due to local ground shift.
Since most gate drivers have internal filters, I might replace these caps by 10k pull down resistors.

Basically, this circuit should provide highest flexibility for rotor position detection. It allows Sensor or QEI feedback, as well as BEMF sensing by measuring the battery and phase voltages with the high speed ADC of the uC. Furthermore, every phase current can be measured separately for best step response in sensorless closed loop control.
In an assembly variant, all phase currents are sensed by one difference amplifier, which saves cost if the different phase currents are not of interest.
For cost and flexibility reasons I prefer discrete shunt resistors with difference amplifiers over hall sensors.

BR,
Florian