1kW Three-Phase Pure Sine Wave Inverter

STM32-Based 3-Phase Inverter with SPWM Control, Protection and Real-Time Monitoring

This project focuses on the development of a 1kW three-phase pure sine wave inverter using an STM32 microcontroller as the main control platform.

The system was designed as an engineering test platform for studying three-phase SPWM generation, power-stage control, voltage and current measurement, protection, filtering, and real-time system monitoring.

Project Overview

The inverter converts a DC supply into a controlled three-phase AC output using an IGBT-based power stage.

The main controller manages the inverter switching signals while continuously monitoring electrical parameters from the power stage.

The system includes:

• STM32-based digital control
• Three-phase SPWM generation
• Complementary PWM with programmable dead time
• IGBT power stage
• Output voltage and current sensing
• DC bus voltage monitoring
• Temperature monitoring
• Hardware fault/protection input
• LCD-based local monitoring
• Adjustable PWM modulation
• Harmonic and waveform analysis capability

System Architecture

The basic control structure is:

DC Supply → IGBT Power Stage → LC Filter → Three-Phase AC Output

The STM32 generates synchronized PWM signals for the three inverter legs. Feedback signals from the power stage are acquired through the ADC channels and processed by the firmware.

STM32 Control System

The STM32 handles the core real-time functions of the inverter.

The firmware is responsible for:

• SPWM generation
• PWM duty-cycle control
• Output frequency control
• Modulation control
• ADC acquisition
• Voltage and current measurement
• Protection monitoring
• Soft-start operation
• Dead-time configuration
• LCD interface
• System settings and status monitoring

The PWM system uses center-aligned complementary switching, making it suitable for driving the high-side and low-side devices of the three-phase IGBT bridge.

Measurement & Protection

Multiple feedback signals are integrated into the controller to provide information about the operating condition of the inverter.

Measured parameters include:

• Three-phase output voltage
• Three-phase current
• DC bus voltage
• Power-related parameters
• Temperature
• Output frequency
• Fault/protection status

The feedback system allows the controller to detect abnormal operating conditions and provides useful information for debugging and power-stage testing.

Local Monitoring

A compact LCD interface provides the operator with real-time information about the inverter.

The display and control interface can be used to view system parameters and adjust selected operating settings without requiring a separate computer.

This makes the platform useful not only as an inverter, but also as a laboratory development and testing system.

Hardware Development

The project combines custom electronics, embedded firmware, and power electronics into a single working system.

Particular attention was given to:

• IGBT gate-drive interface
• PWM synchronization
• Dead-time control
• Analog signal conditioning
• ADC scaling
• Protection inputs
• Power-stage layout
• Noise-sensitive measurement circuits
• Safe interaction between the control and power sections

From Firmware to Hardware

The development process can be summarized as:

Requirement → Circuit Design → PCB Development → STM32 Firmware → PWM Testing → Feedback Calibration → Power-Stage Testing → System Integration

The project is being developed incrementally, starting with low-risk control and measurement testing before progressing toward full-power operation.

Final Result

The result is an STM32-controlled 1kW three-phase inverter platform designed for practical experimentation with SPWM, power electronics, feedback control, and harmonic analysis.

The platform can also serve as a foundation for future development of more advanced inverter functions such as closed-loop voltage regulation, improved protection, harmonic compensation and digital power control.

This project demonstrates the integration of embedded systems, power electronics, PCB design and real-time control into a single engineering platform.

If you are working on an electronic product, industrial machine or IoT system and need a custom PCB or embedded controller, feel free to get in touch.

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