In this project, we’ll build a high-efficiency DC-AC inverter using the SKIIP36NAB126V10 IGBT module. This inverter can be used in applications such as renewable energy systems, backup power supplies, or even small off-grid power applications. The SKIIP36NAB126V10 is a powerful and reliable module specifically designed for such power electronics applications. By the end of this project, you’ll have a functional inverter capable of converting 12V DC to 120V AC, which can power small devices and systems.

Key Components

SKIIP36NAB126V10 IGBT Module

The SKIIP36NAB126V10 is an insulated-gate bipolar transistor (IGBT) module. It is capable of handling large currents and voltages, making it ideal for power electronics. This module is designed for industrial and renewable energy applications and comes with a built-in diode, simplifying the design.

Microcontroller (e.g., Arduino, STM32, or PIC)

A microcontroller will be used to generate the necessary PWM (Pulse Width Modulation) signal to drive the IGBT. The PWM signal controls the switching frequency of the inverter, determining the output waveform.

Power Supply (12V DC)

The inverter will take a 12V DC input, which is common in battery-powered systems. This could be from a 12V lead-acid battery or a solar panel with a charge controller.

Inductor and Capacitors

Inductors and capacitors are used to filter the output of the inverter and smooth the AC waveform.

Heat Sink

Since the SKIIP36NAB126V10 can generate significant heat during operation, a heat sink is needed to keep the module cool and prevent overheating.

Resistors and Diodes

These will be used for feedback and protection circuitry, ensuring that the inverter operates safely and efficiently.

Transformer (Optional)

If you require a specific output voltage or current, a transformer can be used to step up or step down the voltage.

Project Overview

The basic function of a DC-AC inverter is to convert a DC voltage (e.g., 12V from a battery) into an AC voltage (e.g., 120V to power household appliances). This process involves:

1. Switching the DC voltage on and off at a high frequency to generate an AC waveform.

2. Filtering the signal to remove high-frequency switching components, leaving a pure sinusoidal or square wave AC signal.

3. Transforming the voltage (if needed) using a transformer to match the desired output voltage (e.g., from 12V to 120V AC).

Using the SKIIP36NAB126V10, we will handle the switching part, ensuring efficient power conversion. The microcontroller will generate the PWM signals, while the IGBT module will convert those signals into high-voltage AC power.

Step-by-Step Build

1. Circuit Design and Preliminary Considerations

The first step in the project is to design the circuit. The inverter circuit involves switching the DC voltage using the IGBT, followed by a low-pass filter to smooth out the output waveform.

PWM Generation:

The PWM signal will be generated by a microcontroller, such as an Arduino. The duty cycle of the PWM signal will determine the output voltage and waveform of the AC signal. In this case, we’ll use a basic square wave or modified sine wave output.

IGBT Driver:

The SKIIP36NAB126V10 requires a gate driver circuit to control the switching of the IGBT module. The gate of the IGBT needs to be driven with a voltage of about 15V to turn on, and the microcontroller’s 5V logic level is insufficient. Therefore, a gate driver IC (e.g., IR2110) will be used to interface the microcontroller and the IGBT.

Output Filtering:

A low-pass filter will be used to smooth out the high-frequency switching components, providing a cleaner AC waveform. This can be accomplished using an LC (inductor-capacitor) filter. A transformer can be added to step up the voltage to the desired level (e.g., from 12V to 120V AC).

2. Building the Power Stage

The power stage of the inverter is where the actual conversion from DC to AC occurs. Here, the SKIIP36NAB126V10 IGBT module comes into play. It has the following features:

1. Voltage Rating: 1200V

2. Current Rating: 36A

3. Built-in Diode: Helps with switching off the IGBT efficiently.

The SKIIP36NAB126V10 is a module that combines IGBT switches and diodes, which makes it perfect for high-power inverter designs. The module is designed for efficiency, with low on-state voltage drop and fast switching capabilities.

Connect the DC Source to the IGBT:

The 12V DC source will be connected to the input of the IGBT. The output of the IGBT will provide the AC waveform once switched.

Gate Driver:

The gate driver will be connected to the control pins of the SKIIP36NAB126V10 IGBT module. The driver ensures that the IGBT is switched on and off at the correct times according to the PWM signal from the microcontroller.

Heat Management:

Attach a heat sink to the SKIIP36NAB126V10 IGBT module to ensure that it doesn’t overheat during operation. The IGBT can dissipate a significant amount of power, so adequate cooling is essential.

3. Microcontroller Programming and PWM Generation

The microcontroller is programmed to generate a PWM signal with the correct frequency (typically 50Hz or 60Hz for AC power) and duty cycle. The duty cycle will affect the output waveform, so it is important to adjust it for efficient power conversion.

The basic PWM generation works by toggling the IGBT on and off at a high frequency. This frequency will be much higher than the 50Hz or 60Hz AC frequency to reduce the size of the filtering components.

4. Filter and Output Stage

The output of the inverter will be a high-frequency square wave that must be filtered to create a clean AC signal. This can be achieved using an LC filter (inductor and capacitor) that smooths the output into a more sinusoidal waveform.

Inductor and Capacitor:

Connect a suitable inductor and capacitor in series to filter the high-frequency components of the PWM signal. The exact values of the components will depend on the switching frequency of the IGBT and the desired smoothness of the output signal.

Optional Transformer:

If the output voltage needs to be stepped up from 12V to 120V AC, a transformer can be added after the filter. The transformer will increase the voltage while maintaining the frequency.

5. Testing and Adjustment

Once everything is connected, it's time to test the inverter. First, check the voltage and waveform at the output using an oscilloscope. You should see a 120V AC waveform (or the desired output voltage) with a smooth, filtered waveform.

Adjust the PWM frequency and duty cycle to fine-tune the output waveform. Make sure the IGBT module is not overheating by monitoring the temperature of the heat sink.

6. Safety Considerations

Working with high voltages can be dangerous, so ensure proper insulation and safety precautions. Always use a fuse or circuit breaker in the power supply to protect against overcurrent conditions. When working with AC voltage, take extra care to avoid electrical shocks.

7. Conclusion

This DIY project demonstrates how to build a high-efficiency DC-AC inverter using the SKIIP36NAB126V10 IGBT module. The project involves designing a power stage with IGBT switching, generating a PWM signal with a microcontroller, and filtering the output to create a usable AC waveform. By following these steps, you can create an efficient inverter for various applications, from renewable energy systems to backup power supplies.

This project provides valuable experience in power electronics, microcontroller programming, and circuit design, all while building a practical and useful device.