Research on a Phase-Shift-Based Discontinuous PWM Method for 24V Onboard Thermally Limited Micro Voltage Source...

Area of Science:

• Electrical Engineering
• Power Electronics
• Control Systems

Background:

• Micro inverters are crucial for thermally limited applications requiring compact size and efficient heat dissipation.
• Traditional discontinuous pulse width modulation (DPWM) methods improve inverter efficiency but are suboptimal across varying power factors.
• Three-phase voltage source inverters (3ph-VSI) face efficiency challenges due to changing power factors from loads like motors.

Purpose of the Study:

• To develop a generalized DPWM method with an adjustable phase shift angle for optimal efficiency in 3ph-VSI.
• To address the limitations of fixed DPWM methods under diverse operating power factors.
• To enhance efficiency and reduce switching losses in 24V onboard micro inverters for demanding applications.

Main Methods:

• A generalized DPWM method with a continuously adjustable phase shift angle was proposed.
• The method divides operation into five power factor angle intervals for automatic phase shift adjustment.
• Synchronous Reference Frame Phase-Locked Loop (SRF-PLL) was used for real-time power factor calculation.

Main Results:

• The proposed DPWM method improved inverter efficiency by 3-6% across different power factors.
• Switching losses were reduced by 40-50% compared to traditional DPWM methods.
• Experimental validation on a 24V onboard 3ph-VSI platform confirmed efficiency gains and dynamic performance.

Conclusions:

• The adaptive DPWM method offers significant efficiency improvements and loss reduction for 3ph-VSI.
• This technique is highly suitable for miniaturized, thermally constrained inverters.
• The generalized DPWM approach provides optimal performance across a wide range of power factors.