TMS320F280049C: Motor control current spike

RAJAKUMAR RAMU

Part Number: TMS320F280049C
Other Parts Discussed in Thread: C2000WARE, MOTORWARE

Hello All,

During the motor control i am getting current spike around 150mV. which is my ADC full scale voltage . motor is stopping automatically once its reached some speed level.

using internal PGA with 12 Gain. i think comparator is stopping the motor. this current spike are there during the Bottom MOSFET turn on time. i hope ADC will not read this since we are sampling centre of the bottom mosfet on. but comparator will detect this spicks.

i am driving my motor with 60KHz PWM.

please clarify what are all the chance is there to stop the motor.

and also give some idea to configure and eliminate this spick in comparator output using digital filter.

i thought due to cross conduction current spike is there . to solve this i have increased my dead time still current spike is the. so from this we can confirm there is no cross conduction. is there any other option to reduce the current spike in hardware also fine . we are using 1mOhm resistor to measure 200 Amps Peak to peak . with 12 gain PGA.

we use separate kelvin connection for all the phase current measurement.

in the no load itself spike are there .

please help me to solve this problem.

Thanks and regards,

Rajakumar.R

over 4 years ago

0 Navaneeth Narayanasamy over 4 years ago

TI__Intellectual 2910 points

Rajakumar, You could try multiple things to fix the issue: lowering the switching speed of MOSFET's, increase RC filter at PGA input or using digital filter. Please refer to C2000Ware examples for configuring CMPSS.

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

thanks you. Yes i tried all. still i have problem. i don't know what's really happening. during the error motor stopping automatically. some time debugging communication also getting disconnected. some time motor stopping but there is no over current error or there is no any motorVars error. only comparator latch signal is high.

motor is not staring in another case its taking more current.

kindly help me what went wrong.

any basic code is there to check the board for custom design?

thanks and regards

Rajakumar

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

The only other improvement I could see is to make the layout better....

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

Thank you.

Any idea why communication is disconnecting. i am using lunchXL F280049C connected with hardware for debugging.

Regards

Rajakumar.R

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

Please go through this E2E - https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/368668/usb-debugger-disconnecting-running-motorware-labs

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

thanks for the details.

i have one more hardware. in this different version hardware motor is not starting.

please let me know what i have do it. while starting its jerking. and its taking more current.

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

Try running motor in open loop and ensure current and voltage signals are per design. Ensure motor parameters are correct before running in closed loop.

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

Hi Please clarify how to run in open loop.

also explain what is force angle and how its working

how to select user voltage filter pole. how this will affect the performance. where it will be used in the code

please clarify this.

thank you

Regards,

Rajakumar.R

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

Rajakumar, Please refer to instaspin user guide and lab manual available within motorware_1_01_00_18\docs\labs

https://www.ti.com/lit/ug/spruhj1h/spruhj1h.pdf

https://www.ti.com/tool/MOTORWARE

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

Hi I checked with this document . this is having basic details but not the details "spruhj1h". where i can get real calculation and other details. also not much details about force angle

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

Forced-Angle is used for 100% torque at start-up until the FAST rotor flux angle tracker converges within first electrical cycle. Underlying principle is propriety.

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

thanks for the clarification.

i am using "C2000Ware_MotorControl_SDK_2_01_00_00".

is there any motor operating frequency limitation.

our motor we need to run with 40 or 60KHz switching frequency. and motor fundamental frequency is around 3000Hz.

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

60KHz switching frequency should be fine, but ensure current control ISR runs less than 20 - 30Khz so that there's sufficient time for CPU to implement FOC algorithm and other activities. Below parameter can be used to modify the rate at which ISR runs.

#define USER_NUM_PWM_TICKS_PER_ISR_TICK (3)

Filter in voltage sensing circuit also need to be modified to accommodate 3KHz. Refer instaspin user guide for more details.

0 RAJAKUMAR RAMU over 4 years ago in reply to Navaneeth Narayanasamy

Prodigy 95 points

do you mean user voltage filter pole should be 3KHz or less than 3 KHz i need to design?

0 Navaneeth Narayanasamy over 4 years ago in reply to RAJAKUMAR RAMU

TI__Intellectual 2910 points

would be slightly less than 3KHz....refer to section 5.2.4 of user guide.

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TMS320F280049C: Motor control current spike