I have Implemented PLL using MATLAB to find out Voltage angle (ϴ) .But in real time using TMS320F28379D Digital Signal Controller i am facing problems. I could implement Clarke Transformarion from three phase Grid Voltage but i coild not implement PARK transformation since SINE of function need to be write in C code to get Vd , Vq . Please suggest and help me how to bring sine of angle (sine function ) in c using DSC.
Virtually every C development environment comes with a library providing functions like sin(), cos() and tan(). If you are using C2000Ware, the QuickStartGuide says there are math libraries for fixed point calculations as well as floating point.
Usually the name of the corresponding header file is just "math.h", so you have to include the line
#include
somewhere near the top of your source code. It might be that some header files with slightly different names come with C2000Ware.
I hope this will help.
In addition to the good answer above, you could, in case you wish, implement an algorithm to obtain the sine of an angle, I recommend this: https://en.wikipedia.org/wiki/CORDIC
It is easy to implement and very accurate.
Greetings from Mexico
https://en.wikipedia.org/wiki/CORDIC
In "real-life implementations", sin() (and cos()) are often realized via lookup tables covering 0-90 degrees. With some 128 or 256 entries, linear interpolation is adequate to calculate the values inbetween the individual points.
I suggest you search (and read) some of the application notes available from all major DSP manufacturers (namely TI, NXP (ex Freescale MC56F series) and Microchip). There is a wealth of information available - including source code for virtually any "issue" imaginable.
Regards
Many thank you all for your prompt reply. i want to you bring kind notice that i can not use direct SIN & COSINE function since my switching Frequency is 5 KHz ( every 200 micro seconds interrupt will occur ) SINE & COSINE function itself taking 53 cycle( ie 2.62 micro second ) to execute . suggest me some good way to implement sine and cosine of angle...
ARIVAZHAGAN Pa , I am also working on grid tied inverter using dspic33f microcontroller, faced the same problem. how did you solve this problem?
I believe a lookup scheme, as described by U. Dreher (above), using a table sized to provide the resolution you need, thus eliminating (or sufficiently shortening the number of cycles to interpolate, in case you do not have the memory for a direct lookup).
In addition, you can write a script to generate either a data block, or the C-Code to declare and initialize (statically) the table(s).