200W Pure Sine Wave Inverter

DC-to-AC pure sine wave inverter converting 12V battery to 220V/50Hz AC using SPWM — verified on oscilloscope and load tested with multiple AC bulbs

Project Overview

Designed and built a 200W pure sine wave inverter converting 12V DC (battery) to 220V AC at 50Hz using Sinusoidal Pulse Width Modulation (SPWM). The output waveform was verified on an oscilloscope confirming a clean pure sine wave, and the inverter was successfully load tested powering multiple AC LED bulbs simultaneously.

Clean 50Hz pure sine wave output captured on UNI-T oscilloscope confirming correct SPWM operation (left). Successful load test powering multiple AC LED bulbs from a 12V battery — demonstrating full 200W output capability (right).

Key Features

  • Pure Sine Wave Output — SPWM-generated clean sine wave, suitable for sensitive AC loads
  • 200W Output Power — sufficient for lighting, small appliances, and electronics
  • 12V DC Input — operates from standard automotive or sealed lead-acid batteries
  • 220V / 50Hz Output — standard Egyptian/European AC mains voltage and frequency
  • SPWM Control — microcontroller-generated sinusoidal PWM for low harmonic distortion
  • H-Bridge Power Stage — MOSFET H-bridge for efficient DC switching
  • Step-Up Transformer — boosts the switched DC to 220V AC
  • Oscilloscope Verified — sine wave output confirmed on UNI-T oscilloscope
  • Load Tested — validated powering multiple AC LED bulbs under real load

Hardware Architecture

Block Implementation
DC Input 12V battery (automotive / sealed lead-acid)
SPWM Generation Microcontroller — sinusoidal PWM signal generation at 50Hz
Power Stage MOSFET H-bridge — high-frequency switching of DC input
Transformer Step-up transformer — low-voltage switched AC → 220V AC output
Output Filter LC filter — smooths SPWM switching into clean sine wave
Verification UNI-T oscilloscope — waveform capture and frequency confirmation

Technologies & Tools

  • Embedded C — SPWM table generation and timer configuration
  • Power electronics design — H-bridge MOSFET gate drive, dead-time control
  • Transformer design and selection
  • Oscilloscope measurement and waveform analysis

Key Achievements

✅ Generated a pure sine wave at 220V / 50Hz from a 12V DC source
✅ Verified clean sinusoidal output on an oscilloscope
✅ Successfully powered multiple AC LED bulbs under full load
✅ Implemented SPWM with correct dead-time to prevent shoot-through
✅ Achieved 200W output power rating