I have to use Space vector modulation (SVM) technique for Current sourced Inverters. Can anyone suggest how I will start to simulate CSI by using SVM?

My research topics is on designing and simulating Current source inverters (CSI) for Off-shore wind turbine-based power plants. I have to use Space vector modulation (SVM) technique for CSI based inverters. As I am new in this field. Can you suggest how I will start to simulate CSI by using SVM?

Answer 1

[Sanju]

Hi Anik Baul,

I understand that you want to simulate a Current Source Inverter (CSI) using Space Vector Modulation (SVM) in MATLAB, here are some steps you can follow through,

• Start by defining the parameters of your CSI system, including the DC link voltage, modulation index, and switching frequency.
• Create the reference current waveform that you aim to achieve using SVM. Typically, this waveform comprises three-phase sinusoidal currents.
• Implement the SVM algorithm to determine the switching states of the CSI switches based on the reference current waveform.
• Utilize the determined switching states to generate Pulse Width Modulation (PWM) signals for the CSI switches.
• Simulate the CSI system by modelling switches, inductors, and capacitors, and applying the PWM signals to the switches.
• Analyse the simulation results to evaluate the performance of the CSI system.

For implementing SVM for a CSI system in MATLAB, you can refer to the following example code,

% Define parameters 
Vdc = 400; % DC link voltage 
m = 0.8; % Modulation index 
fsw = 5e3; % Switching frequency 

% Generate reference current waveform 
t = 0:1/(10*fsw):1/fsw; % Time vector 
Iref = m*sin(2*pi*fsw*t); % Reference current waveform  

% Implement SVM algorithm 
T = 1/fsw; % Switching period 
Ts = T/6; % Sampling time 
t_svm = 0:Ts:T; % SVM time vector 
Vref = sqrt(2/3)*Vdc*m*sin(2*pi*fsw*t_svm); % SVM reference voltage waveform  

% Determine switching states 
T1 = T/2 - Ts/2; 
T2 = T/2 + Ts/2; 
T3 = T - Ts/2; 
T0 = T; 
S1 = (Iref >= Vref); 
S2 = (Iref >= -Vref); 
S0 = ~S1 & ~S2; 
 
% Generate PWM signals 
PWM1 = (t >= T1) & (t < T2); 
PWM2 = (t >= T2) & (t < T3); 
PWM0 = (t >= T3) | (t < T1); 

% Simulate CSI system 
% ... (model the switches, inductors, and capacitors, and apply the PWM signals) 
 
% Analyse simulation results 
% ... (evaluate the performance of the CSI system) 

The above code provides a basic framework for simulating a CSI system using SVM in MATLAB. You will need to fill in the missing parts specific to your system, such as modelling the switches, inductors, and capacitors, and analysing the simulation results.

For modelling switches, inductors, and capacitors in the CSI system simulation, leverage MATLAB's Simscape Electrical toolbox. This toolbox furnishes a comprehensive array of components and blocks for power electronic system modelling,

• For switches, employ the "Ideal Switch" block from the Simscape Power Systems toolbox, specifying switch states based on SVM-generated PWM signals.
• Model inductors using the "Inductor" block, defining inductance values and terminal connections.
• For capacitors, utilize the "Capacitor" block, specifying capacitance values and terminal connections.

You can also refer to the following documentation links for further information,

https://www.mathworks.com/products/simscape-electrical.html

https://www.mathworks.com/help/sps/powersys/ug/building-and-simulating-a-simple-circuit.html

Hope this helps!