I have a laplace transfer-function G(s)=k(1+sT)/s*2 which I need the discrete-time version G(z) using impulse invariance method. Using partial fractions I get G(s) = c1/s + c2/s^2 c1=kT and c2=k However when I use Matlab c2d and select "impulse" it gives me a different version though the first term c1 is right. Matlabs second term c2 is negative. I assume for multiple poles something is different.
Impulse invariance method
Started by ●November 12, 2019
Reply by ●November 19, 20192019-11-19
On Wednesday, November 13, 2019 at 9:11:02 AM UTC+13, gyans...@gmail.com wrote:> I have a laplace transfer-function > > G(s)=k(1+sT)/s*2 > > which I need the discrete-time version G(z) using impulse invariance method. > > Using partial fractions I get > > G(s) = c1/s + c2/s^2 > > c1=kT and c2=k > > However when I use Matlab c2d and select "impulse" it gives me a different version though the first term c1 is right. Matlabs second term c2 is negative. > > I assume for multiple poles something is different.Sorted it. Forgot that a double integrator has a Ts^2 term