Hybrid PWM Techniques for a DCM-232 Three-Phase Transformerless Inverter with Reduced Leakage Ground Current.

Area of Science:

• Electrical Engineering
• Power Electronics
• Renewable Energy Systems

Background:

• Transformerless inverters are essential for photovoltaic (PV) systems to improve efficiency.
• Controlling these inverters requires advanced Pulse Width Modulation (PWM) strategies to mitigate leakage ground currents.
• Existing PWM techniques face challenges in balancing efficiency and safety in transformerless topologies.

Purpose of the Study:

• To propose three novel hybrid PWM methods for a DCM-232 three-phase transformerless inverter.
• To evaluate the effectiveness of these methods in reducing leakage ground current and improving efficiency.
• To ensure the proposed methods comply with international standards for PV inverter applications.

Main Methods:

• Hybrid PWM methods combining carrier-based PWM and space vector modulation concepts.
• Calculation of time intervals for active and null vectors.
• Digital signal processing using Boolean functions to generate control signals.
• Numerical simulations and experimental validation.

Main Results:

• The proposed hybrid PWM methods effectively reduce leakage ground current.
• Significant improvements in inverter efficiency were observed.
• The modulation techniques demonstrated performance compliant with international standards.
• Validation through both simulations and experimental tests confirmed the strategies' viability.

Conclusions:

• The developed hybrid PWM strategies are suitable for transformerless three-phase PV inverters.
• These methods offer a viable solution for enhancing the performance and safety of PV systems.
• The research contributes to the advancement of power electronics control for renewable energy applications.