Introduction

This interactive simulation allows you to explore the behavior of a buck-boost converter, a DC-DC power converter that can either step up or step down voltage from its input to its output. The simulation provides real-time visualization of voltage and current waveforms as you adjust circuit parameters.

Getting Started

1. Set your circuit parameters (input voltage, inductor, capacitor, load resistor)
2. Adjust the simulation parameters (duty cycle, switching frequency)
3. Click "Run Simulation" to see the results
4. Use the waveform visualization tools to analyze the behavior

Circuit Parameters

• Input Voltage: The DC voltage source at the input of the converter
• Inductor: Energy storage element that stores energy when the switch is ON
• Capacitor: Filters the output voltage ripple
• Load Resistor: Represents the load connected to the converter output

Simulation Parameters

• Duty Cycle: The percentage of time the switch is ON during each switching period
• Switching Frequency: How fast the switch turns on and off
• Simulation Time: Duration of the simulation

Advanced Parameters

• MOSFET R_ds(on): On-state resistance of the MOSFET switch
• Diode Forward Voltage: Voltage drop across the diode when conducting
• Inductor DCR: DC resistance of the inductor
• Capacitor ESR: Equivalent series resistance of the capacitor

Buck-Boost Converter Operation

The buck-boost converter operates in two phases:

• Switch ON: Energy is stored in the inductor from the input source, output is isolated
• Switch OFF: Energy from the inductor is transferred to the output through the diode

The output voltage can be higher or lower than the input voltage, with the relationship: V_out = -V_in × D / (1 - D), where D is the duty cycle. Note that the output polarity is inverted.

Waveform Analysis

The simulation displays two main waveform charts:

• Voltage Waveforms: Shows input voltage, output voltage, and switch voltage
• Current Waveforms: Shows inductor current, MOSFET current, diode current, and load current

Use the zoom and pan controls to examine specific parts of the waveforms. The box zoom feature allows you to zoom into a specific area by clicking and dragging.

Saving and Comparing Simulations

You can save simulation results and compare different scenarios:

1. Run a simulation
2. Enter a name for the simulation and click "Save"
3. Run another simulation with different parameters
4. Select the saved simulation from the dropdown to compare it with the current one

Exporting Data

You can export simulation data in several formats:

• Export Data: Saves all waveform data as a CSV file
• Screenshot: Captures the current waveforms as a PNG or JPEG image
• Export Analysis: Saves the results of advanced analysis as a text file

Advanced Analysis

The simulation offers several advanced analysis tools:

• Transient Analysis: Measures rise time, settling time, overshoot, and ripple
• Frequency Response: Analyzes the frequency characteristics of the converter
• Parametric Sweep: Examines how efficiency and output voltage change with duty cycle
• Thermal Analysis: Estimates component temperatures based on power dissipation

Tips for Best Results

• Start with the default parameters and make gradual changes to understand their effects
• Use higher resolution for more accurate results (but slower simulation)
• For better visualization of ripple, zoom in on the steady-state portion of the waveforms
• Save important configurations for future reference
• Note that buck-boost converters have inverted output polarity