SimPowerSystems | ![]() ![]() |
Library
Description
The Series RLC Branch block implements a single resistor, inductor, or capacitor, or a series combination of these. To eliminate either the resistance, inductance, or capacitance of the branch, the R, L, and C values must be set respectively to 0, 0, and infinity (inf
). Only existing elements are displayed in the block icon.
Negative values are allowed for resistance, inductance, and capacitance.
Dialog Box and Parameters
Measurement |
Label |
Example
Obtain the frequency response of a fifth-harmonic filter (tuned frequency = 300 Hz) connected on a 60 Hz power system. This example is available in the psbseriesbranch.mdl
file.
The network impedance in Laplace domain is
To obtain the frequency response of the impedance you have to get the state-space model (A B C D matrices) of the system.
This system is a one-input (Vsource) and one-output (Current Measurement block) system. If you own the Control System Toolbox, you can get the transfer function Z(s) from the state-space matrices and the bode
function as follows:
[A,B,C,D] = power2sys('psbseriesbranch');
freq = logspace(1,4,500);
w = 2
*freq;
[Ymag,Yphase ] = bode(A,B,C,D,1,w);
% invert Y(s) to get Z(s)
Zmag = 1./Ymag;
Zphase = -Yphase;
subplot(2,1,1)
loglog(freq,Zphase)
grid
title('5th harmonic filter')
xlabel('Frequency, Hz')
ylabel('Impedance Zmag')
subplot(2,1,2)
semilogx(freq,Zphase)
xlabel('Frequency, Hz')
ylabel('phase Z')
grid
You can also use the Impedance Measurement block and the Powergui block to plot the impedance as a function of frequency. In order to measure the impedance you must disconnect the voltage source.
See Also
Parallel RLC Branch, Parallel RLC Load, Series RLC Load
![]() | Saturable Transformer | Series RLC Load | ![]() |