【Advanced】DC_AC Single-Phase Bridge Active Inverter Circuit Simulink Model Simulation

# 1. Fundamentals of Simulink Modeling

Simulink is a simulation software with a graphical user interface designed for modeling, simulating, and analyzing dynamic systems. The fundamental principle is to break down the system into interconnected modules, where each module represents a specific function or component within the system. By connecting these modules, one can construct a simulation model of the entire system.

In Simulink, these modules are known as "blocks," which can be basic blocks (such as gains, integrators, differentiators) or custom blocks (such as user-written functions or subsystems). Blocks are connected through "lines," which signify the flow of signals. By setting the parameters of the blocks and the relationships between the lines, the behavior of the system can be defined.

# 2. Simulink Modeling Principles and Simulation Environment Setup

### 2.1 Fundamentals of Simulink Modeling

Simulink is a graphical modeling and simulation tool within MATLAB, intended for designing, simulating, and analyzing dynamic systems. It offers an intuitive user interface that allows users to create system models by dragging and dropping blocks. A Simulink model consists of the following elements:

- **Blocks:** Represent components in the system, such as gains, integrators, transfer functions, etc.
- **Signal Lines:** Connect blocks and represent the flow of signals.
- **Parameters:** Specify numerical values that define the behavior of blocks.

Simulink employs discrete-time simulation, approximating continuous-time systems as a series of discrete time steps. The simulation process is as follows:

1. **Initialization:** Set the initial conditions and parameters of the model.
2. **Computation:** Calculate the system state and output for each time step.
3. **Update:** Update the state of blocks and signal values.
4. **Repeat:** Repeat steps 2 and 3 until the simulation ends.

### 2.2 Setting Up the Simulation Environment and Parameter Configuration

**Setting Up the Simulation Environment**

1. Open MATLAB and启动 Simulink.
2. Create a new model.
3. Drag and drop blocks from the Simulink library into the model window.

**Parameter Configuration**

Each block has its own parameters that need to be set according to the actual system. For example:

- **Gain block:** Set the gain value.
- **Integrator block:** Set the integration constant.
- **Transfer function block:** Set the coefficients of the numerator and denominator of the transfer function.

**Simulation Parameters**

In addition to the block parameters, simulation parameters also need to be configured, including:

- **Simulation step size:** Specifies the time step for the simulation.
- **Simulation duration:** Specifies the duration of the simulation.
- **Solver:** Select a solver for solving differential equations.

**Code Blocks**

% Setting simulation parameters
sim_step = 0.001; % Simulation step size
sim_time = 0.1; % Simulation duration
solver = 'ode45'; % Solver

% Setting block parameters
gain = 10; % Gain value
tau = 0.1; % Integration constant
num = [1]; % Transfer function numerator
den = [1, tau]; % Transfer function denominator

% Building a Simulink model
simulink_model = simulink.Model('DC-AC_Inverter');
gain_block = simulink.Gain('Gain', 'Gain', gain);
integrator_block = simulink.Integrator('Integrator', 'InitialCondition', 0, 'Gain', tau);
transfer_function_block = simulink.TransferFcn('Transfer Function', 'Numerator', num, 'Denominator', den);

% Connecting blocks
add_block(gain_block, simulink_model);
add_block(integrator_block, simulink_model);
add_block(transfer_function_block, simulink_model);

connect_blocks(simulink_model, 'Gain/Out1', 'Integrator/In1');
connect_blocks(simulink_model, 'Integrator/Out1', 'Transfer Function/In1');
connect_blocks(simulink_model, 'Transfer Function/Out1', 'Gain/In1');

% Setting simulation parameters
set_param(simulink_model, 'FixedStep', sim_step);
set_param(simulink_model, 'StopTime', sim_tim