C2000WARE: TIDM 1000 ISR Frequency

Hi Annu,

Apologies for the delay, please expect the response by 31st May. 

Best, 

Uttam

Please Reply ASAP . That will help me alot

Hi Annu, 

Sorry for the delayed response. The expert on this topic was OOO. Let me know if you have any further questions,

1. Question 1: What is VIENNA_ISR_CONTROL_FREQUENCY_HZ ? Is ISR executions occurring at this frequency?

reference design runs at 50kHz of switching frequency. The project consists of an interrupt service routine, which is called every PWM cycle, called controlISR(), where the control algorithm is executed. so this is 50kHz/3 

2. Question 2 : What is VIENNA_ISR_10KHZ_FREQUENCY_HZ  frequency , this frequency is used in power_measure_sine_analyzer(). Is this frequency effecting the output voltage?

. A slower 10-kHz routine tenkHzISR() is called for instrumentation and to run some slower tasks that require timing accuracy. This looks like its helpful while using power_measure_sine_analyzer() only. it depends on which device you are looking this into?

3. My requirement is 115 V, 400 Hz input line frequency . I have already checked upto 350 Hz it is working with PWM switching frequency 200Khz and Control loop frequency fsw/3. But it is not working for 400 Hz , Is there a way I can make it work??

Can you let me know what device you are running this on? Have you tried running the Lab-1 (open loop test)? When you mention its not working. I assume the power topology is not working. 

I can check with few other experts around and get back to you soon.

Best Regards,

Uttam

Hi Annu,

I see you had a previous thread in place regarding question 3.

 https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1224322/tidm-1000-to-operate-the-tidm-1000-at-input-line-frequency-400-hz-it-is-working-at-250-hz-input-line-frequency.

As mentioned by the expert the software & hardware is designed and validated for 50/60Hz only. the higher frequency might need some HW & SW changes which is not validated in the reference design. 

Best Regards,

Uttam

Hii Sir

Thank you so much for your reply

I am using the build 4 and my controller is F28379D.

Case 1: I have checked for 300 Hz input line frequency, with pwm switching frequency 200 khz and ISR Control frequency 200khz/3 output voltage  is             boosting (i.e PWM generating properly and output voltage Vdc is coming as expected ) .

Case 2 : But when the checked for 400 Hz with pwm switching frequency 200 khz and ISR Control frequency 200khz/3 ,output voltage  is  not  boosting (i.e PWM is  generating properly and output voltage Vdc is not coming as expected ) .

Can you give any idea why this happening for 400 Hz Frequency??

Waiting for your reply.

Thanks & Regards

Hi Annu,

One question:  how are you changing the input AC freq. to 350Hz as the main.sysconfig generates only 60Hz. not even 50Hz?

For the 400Hz, as it is build 4 - I think with such fast sensing might not take all the samples needed. this might cause the control loop issues.

Best Regards,

Uttam 

Hello Sir

how are you changing the input AC freq. to 350Hz as the main.sysconfig generates only 60Hz. not even 50Hz?

I AM changing VIENNA_MAX_GRID_FREQ = 500 HZ in code  And the variable generated by main.sysconfig (AC_FREQ_HZ       ((float32_t)60))  varibale is not used anywhere in the code.

Can you please suggest how to sense all the samples at 400 Hz.?

Let me add another expert for feedback on this. 

Hi Annu,

Can you pls use the non-powerSUITE version of code to change the AC freq? We have only tested with 50Hz and 60Hz. And as you mentioned, this parameter may not be used in the control, but higher AC input freq may impact the parameter accuracy/system performance which is based on the s/w algorithm.

Regards,

Chen

Thank you so much for your reply

So As I can understand my hardware is sufficient to operate at 400 Hz Is it Right?

 but higher AC input freq may impact the parameter accuracy/system performance which is based on the s/w algorithm.

Which parameter accuracy/system performance is effecting that I am unable to figure out ? Is my ADC (12 bit ) is not sufficient to sense the board parameter at higher frequency or my ISR frequency ( 50 KHz) is not proper or my PWM switching frequency (50 kHZ)  is not sufficient?

Could you please help me figure out what is wrong in code?

And Could you please provide any MATLAB stimulation model for tidm 1000 that will help alot?

Thank you

Regards

Annu

Hi Annu,

Avoid confusion, when I say the higher AC input freq may impact the parameter accuracy/system performance which is based on the s/w algorithm.

I am mainly referring to "POWER_MEAS_SINE_ANALYZER_run" which has the parameters tuned for 50/60Hz. those you need to take a look at it when moving to 400Hz input.

50kHZ ISR is sufficient for 50Hz switching freq. 

Regards,

Chen