DIY Pure Sine Wave Inverter Using EGS002 SPWM Module
by Estiak khan Jhuman in Circuits > Electronics
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DIY Pure Sine Wave Inverter Using EGS002 SPWM Module
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Build a Pure Sine Wave 200-300W Power Inverter
The goal of this inverter project is to create a device capable of generating stable AC output from a DC source. This is achieved through high-frequency switching, power MOSFETs, and a transformer. The inverter is ideal for backup power applications or powering small loads like LED lights, fans, or low-power electronics.
Supplies
How the Inverter Works
Inverter circuits convert DC power from a battery into AC power. In this design:
- EGS002 Module generates SPWM (Sine Pulse Width Modulation) signals to control the MOSFETs.
- The MOSFETs rapidly switch the DC current on and off, creating a high-frequency AC waveform.
- A UPS transformer then steps up the low-voltage AC to a standard AC voltage (110V or 220V).
- The resulting AC output can power small appliances, providing a portable AC source.
Components Required
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1. Core Components
- IRFZ44N / IRF3205 MOSFETs: These handle high currents and act as the main switching components.
- EGS002 Module: This SPWM module generates the sine wave control signal, ensuring smooth and stable AC output.
- UPS Transformer: Converts low-voltage AC from the MOSFET switching to a higher AC voltage (110V or 220V).
- Battery (12V): Provides the DC input power for the inverter.
2. Supporting Components
- Resistors: 10Ω and 4.7kΩ resistors to control current and voltage through the circuit.
- Capacitors:
- 4700µF, 100µF, and 10µF electrolytic capacitors to filter and smooth the DC and AC voltages.
- 104 ceramic capacitor for additional smoothing.
- Diodes:
- FR107 fast recovery diode for efficient switching.
- 1N4148 Zener Diode for voltage regulation.
- Feedback Capacitor (225J): Adds stability to the transformer’s feedback loop.
- Fuse 15A: Protects against overcurrent.
- Switch: Controls power to the circuit.
- AC Socket: For output AC connections.
- JLCPCB Custom PCB Board: Organizes components for a stable, neat layout.
Choosing the Right MOSFETs
Selecting the best MOSFETs is crucial for efficient and reliable inverter performance.
- IRFZ44N: Rated for 49A and 55V, a cost-effective option for moderate power.
- IRF3205: Rated for 110A and 55V with lower R_DS(on), which leads to less heating and better efficiency, ideal for this 200-300W inverter.
- 95N03 MOSFET: Another option with a very low R_DS(on), suitable for high-efficiency needs but not as widely available as IRF3205.
Recommendation: IRF3205 is the best choice due to its high current rating, low on-resistance (for minimal heating), and durability, especially for extended use at high loads.
Circuit Block Diagram
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Detailed Circuit Design
1. Battery and Fuse Setup
- The 12V battery provides DC power to the circuit.
- A 15A fuse connects in series with the positive terminal, offering overcurrent protection.
2. EGS002 Module
- The EGS002 SPWM module controls the MOSFET gates, creating a 50Hz or 60Hz sine wave output.
- Connect the battery directly to the module’s power input, ensuring stable DC supply.
3. MOSFET Switching Stage
- Connect IRF3205 MOSFETs in parallel, as they will handle the inverter’s main power load.
- The EGS002 drives the gates of these MOSFETs, rapidly switching them on and off, producing an AC waveform.
- Gate Resistors (10Ω): Add a 10Ω resistor to each MOSFET gate pin to limit inrush current and prevent gate damage.
4. Transformer
- The UPS transformer is connected to the MOSFETs’ output to convert the low-voltage AC into high-voltage AC.
- The 225J feedback capacitor stabilizes the transformer’s output, ensuring stable AC voltage output.
5. Filtering Capacitors
- Use 4700µF, 100µF, and 10µF capacitors for smoothing the DC and AC waveforms.
- Place the capacitors across the power input and output to reduce noise and smooth out voltage spikes.
6. AC Output and Socket
- The transformed AC voltage is routed to the AC socket for connecting appliances.
- Add a switch to control the inverter’s power output, allowing you to turn off the AC when not in use.
Heat Dissipation and MOSFET Protection
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Proper heat dissipation is crucial for MOSFETs in power circuits due to the high currents involved. Without adequate cooling, MOSFETs can overheat and fail.
- Heat Sink Selection:
- Use large aluminum heatsinks for each MOSFET, capable of dissipating 20-50W.
- The IRF3205 MOSFETs, in particular, require large heatsinks if running continuously under load.
- Thermal Paste:
- Apply thermal paste between the MOSFET and heatsink to enhance heat transfer.
- This reduces heat build-up, prolonging MOSFET life.
- Active Cooling:
- Place a 12V fan near the heatsinks to maintain airflow, especially useful if the inverter will be used continuously.
Protecting MOSFETs From Overload and Damage
- Overcurrent Protection:
- The 15A fuse prevents high current from damaging the MOSFETs, protecting the circuit from overloads.
- Snubber Circuit:
- Add a snubber circuit (a combination of a resistor and capacitor) across each MOSFET to absorb voltage spikes and protect against transients.
- Use a 100Ω resistor and a 0.1µF capacitor in series to provide adequate snubbing.
- Gate Protection:
- Place a 15V Zener diode across the gate and source pins of each MOSFET. This prevents excessive gate voltage, which could permanently damage the MOSFET.
- Capacitive Load Isolation:
- Avoid powering inductive or capacitive loads directly from the inverter, as they can cause high inrush currents. Start the inverter with a light load to reduce strain on the MOSFETs.
AC Load Connection
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- Install the AC Socket:
- Connect the AC output from the transformer’s secondary winding to the AC socket, allowing easy connection of appliances.
- Grounding:
- Ensure the AC output socket is grounded to protect against potential shocks and improve device safety.
- Load Testing:
- Begin with a small load, such as a light bulb, to verify the AC output.
- Gradually increase the load to reach 200-300W, monitoring the voltage stability.
Final Testing and Optimization
- Frequency and Voltage Check:
- Use an oscilloscope to check the output frequency and ensure it’s set to 50Hz or 60Hz.
- Verify the output voltage matches the expected 110V or 220V, depending on your region.
- Thermal Monitoring:
- Run the inverter under load and monitor the temperature of MOSFETs. If they become excessively hot, increase heatsink size or add more fans.
- Long-Term Operation:
- For extended use, check connections periodically and ensure all components, especially MOSFETs and capacitors, are functioning correctly.
Why Choose JLCPCB for Your PCB Needs?
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When building your inverter or any other DIY electronics project, having a high-quality, reliable PCB is essential for performance and durability. JLCPCB is a trusted choice for PCB manufacturing, offering professional-grade PCBs at affordable prices, starting at just $2 for 1-4 layer boards!
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Order Your PCB with Ease!
- Design Your Circuit: Complete your design in any PCB design software, like KiCad or Altium.
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Conclusion
This 200-300W inverter project provides a practical and reliable solution for portable AC power, ideal for small appliances or backup power in emergencies. The combination of IRF3205 MOSFETs, a custom PCB, and effective cooling measures ensures long-lasting performance and efficiency. With careful assembly and testing, this DIY inverter will provide smooth AC power, making it a versatile addition to any electronics toolkit.
Video Reference
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