Home UPS

Home UPS Project Overview

In this project, we have developed a compact Home UPS designed to provide uninterrupted power during outages, primarily for desktop computers and other devices that require a continuous power supply.

Key Features:

Compatibility: The UPS supports various battery types, including Lithium-Ion, Lead-Acid, LiFePO4, and more, allowing flexibility based on user preference or availability.
Connections:
- AC Input: Located on the right side of the UPS, an AC plug connects the unit to the main power source.
- Battery Connection: An XT60 connector at the back interfaces with a 12V battery.
- AC Output: An AC socket at the back supplies power to the connected load.
Cooling System: Two rear-mounted fans ensure efficient cooling of internal components.
User Interface:
- LCD Display: A front-facing screen provides real-time information about the UPS status and operating parameters.
- Power Switch: A conveniently placed switch next to the LCD allows users to turn the UPS on or off.

Functionality:

When powered on, the UPS operates as follows:

Normal Operation: While main power is available, the UPS directly supplies power to the connected load from the mains.
Power Outage: In the event of a power failure, the UPS seamlessly switches to inverter mode, drawing power from the connected battery to maintain uninterrupted operation. The transition is exceptionally fast, ensuring the devices remain unaffected.

This compact, efficient design makes it a reliable solution for ensuring uninterrupted power supply to critical devices.

How This Project Works

To develop this UPS, we designed, built, and tested numerous circuits to identify the most efficient and reliable configurations. The result is a highly efficient UPS with an efficiency exceeding 92%. Here's a breakdown of how the system functions:

Development Process:

Circuit Design and Testing: We experimented with various circuit designs and components, optimizing for performance and reliability.
Efficiency Optimization: Each stage was fine-tuned to achieve maximum efficiency and seamless operation.

Operational Overview:

Battery Configuration:
- The UPS can work with various types of batteries. However, the battery type and parameters must first be configured through the software.
- Once connected, the battery becomes the primary power source during outages.
Power Conversion Stages:
- Stage 1: Push-Pull Conversion:
  - The 12V DC input from the battery is converted to high-voltage DC (approximately 400V) using a push-pull circuit driven by a custom driver.
- Stage 2: DC-to-AC Conversion:
  - The high-voltage DC (400V) is then converted to 220V AC at 50Hz using a full-bridge inverter with a precision driver.
  - Initially, we used a modified sine wave driver. However, for improved performance and compatibility, we upgraded to a pure sine wave driver controlled by an Arduino. The output is further filtered using capacitors and inductors to ensure a clean sine wave.
Safety and Protection:
- Extensive safety features have been implemented in the design, including:
  - Over-voltage and under-voltage protection
  - Short-circuit protection
  - Overload protection
  - Over-temperature protection
  - And more to ensure reliability and longevity.
Monitoring and Display:
- All critical parameters, including input and output values, are continuously monitored and displayed on the LCD screen, providing real-time feedback to the user.

This meticulous design process and attention to detail result in a robust and efficient UPS that ensures safe, reliable, and uninterrupted power delivery.

Additional Features and Highlights

Integrated SMPS Charger:
- The UPS includes an internal SMPS 12V power supply designed to charge the connected battery efficiently.
- The charging process adapts to the specific battery type configured, ensuring optimal performance and longevity.
Versatile and Compact Design:
- Despite its compact size, the UPS is highly versatile, compatible with various battery types, and suitable for a wide range of applications.
Output Specifications:
- Voltage: The default output is 220V AC at 50Hz, but it can be reconfigured as needed.
- Power: The maximum output power is 1kW, providing robust performance for most devices.
- Waveform: The output waveform is a pure sine wave, ensuring compatibility with sensitive electronics.
Comprehensive Protection:
- The UPS is equipped with multiple safety features, including protection against over-voltage, under-voltage, short circuits, overload, and overheating, ensuring reliable and safe operation.

Development and Customization

I have dedicated significant time and effort to selecting the best components and creating a modular, easy-to-build design for this UPS. If you're interested in purchasing the complete circuit along with detailed guidance, feel free to contact me.