Having problems in starting Bldc motor with mc33035

Thread Starter

aaditpj

Joined Jul 3, 2014
7
I have made a driver circuit for a sensored bldc motor using mc33035. This circuit is similar to the application circuit(given in fig.19 and fig 36) in the ic's data sheet. I have used TIP127 and TIP122 as upper and lower gate mosfets respectively. The frequency is determined by a 10kΩ resistor and 10nf capacitor. The current limiting is set for 4.25 A by using a 0.5Ω resistor and voltage reference of 2V given the the op-amp integrated in the given ic.


however I am having problem in starting the motor. The motor does not start on its own for some positions of the the rotor and also once I stop the motor by using brake or by making its speed 0, it does not start on its own. it also starts vibrating at some rotor positions.The motor runs well once i start the motor by hand. The motor has sensors at 120° and is a out-runner motor.
 

THE_RB

Joined Feb 11, 2008
5,438
It's a common problem with sensored BLDC drivers.

Google "motor starting system on sensored BLDC driver" or similar. :)
 

THE_RB

Joined Feb 11, 2008
5,438
Keep trying!

It's a common problem, I think one common fix is to first manually activate a couple phases in sequence to give the rotor a "kick" which gets the hall sensors working and gets the motor phased right.
 
With a sensored system, there should never be any dead spots, if there are, the motor is either phased wrong or you have a 60/120deg sensor spacing issue, some controllers do have a select pin for this.
 

Thread Starter

aaditpj

Joined Jul 3, 2014
7
yes pin22 is pulled low for 120 degree sensor angle. And I have confirmed with the motor manufacturer for the sensor angle and he too told me that the sensors were placed at 120 degrees. And for the motor works perfectly fine if I connect it with with an another circuit bloc driver circuit that is a bit different.
 

Thread Starter

aaditpj

Joined Jul 3, 2014
7
Ok it was a problem with the IC I suppose. I ordered other ones and the circuit works perfectly well. Thanks for the help.
 

bertus

Joined Apr 5, 2008
21,364
Hello,

You just made a necropost.
The OP has not been online since jul 2016 and will likely not answer.
You say you made figure 36 of the datasheet:

MC33035_fig36.png

What is not working?
You might also want to have a look at the attached application note.

Bertus
 

Attachments

MaxHeadRoom

Joined Jul 18, 2013
23,115
Pin 9 is used as a current sense input it monitors the current flow through .05Ω resistor which is in the current path to common for all the Mosfets..
Shuts the outputs off in the case of over current.
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
23,115
Here is a App note from Motorola on the 33035 and its companion 33039 IC for closed loop, They used to make a board available for prototyping as seen in the PDF.
Max.
 

Attachments

Last edited:
BLDC motor I use : 700W, max current 40A. I'm using tip122 and tip127 for up and low gate, source from battery 1800mhA, 25-50 discharge. I'm also checking sircuit, but when I start, tip are very hot. I think the problem is battery.
 
Top