Hi, I have been searching on the forums and couldn't find a proper answer to my problematic. I have seen that many people tried but couldn't find any real solution.
My problem here is that, I am developing a code in Labview FPGA to have a phase angle control that will let me have voltage variations, this code is to send a pulse to a set of TRIACs within a range of 0 to 8ms (half wave cicle of 60 Hz) each time it detects a zero crossing but the pulse doesn't seems to be changing or moving with my PID code, and even if I manually input the milisecond when I want the program to launch a pulse it doesn't seems to do it. This code used to move the pulse within the 0 to 8 miliseconds range manually, I veryfied that in the osciloscope.
On the hardware ,there is a TRIAC on each line of the three phase wye source and it has a MOC3011 to separate the circuit from the Labview, then after that there is a set of transformers in delta and then it goes to a three phase bridge rectifier to have a DC output.
The equation I am using to determine the alpha angle is Vdc = (1.35) * (VrmsL-L of the secondary transformer) *( Cosine(alpha) ) so I just take alpha and there is when my other problem comes, FPGA cannot implement inverse cosine functions, so I sent that value to my HOST (PC) with FIFO to use the Inverse Cosine Function and then return it to the FPGA with another FIFO and that sometimes gives me the error 50400 only at the FIFO that goes from HOST to FPGA.
Time ago the code could only "activate" the TRIACs at 60 degrees to 120 degrees only with it was with a lot of noise and that was because I needed to do some modifications in hardware to have a correct signal cut and proper gate current and hold current, but now my code doesn't varies the pulse, sometimes it fires it at zero degrees (as soon as the zero crossing occurs) and my HOST reads values for like 2 seconds and the stops having any reading, it just keeps running without doing anything different. My Setpoint doesn't seems to be doing anything at all in the code.
I am using the NI 9074 cRIO, for current input I use the NI 9227 (I initialize it on the FPGA code) and the NI 9215 (to read voltage feedback from a resistor), for the output signals I am using NI 9263 wich gives me 10 volts output, and I am wondering if I should start using the Digital output module instead to activate the TRIACs (NI 9474) since it seems to be faster. My FPGA code is commented.
I am pretty lost with this proyect I am working on, I attach the whole project and if there is needed more info about hardware or the circuits please let me know.