Integrated AC Power Cycling Platform with Automated Characterization for T-Type Power Module in Photovoltaic Applications

The reliability of power electronic modules can be assessed by stress testing the devices and characterizing them. AC power cycling provides the platform to stress the devices in exact field conditions. This paper exhibits the existing state of the art in AC power cycling test benches and demonstrates the uniqueness of the newly developed test bench for PV inverter application. Characterizing is an essential part of the reliability model development. It becomes a challenge to characterize the T-type IGBT modules and visualize results because they are complex and time-consuming, especially for power modules based on a non-phase-leg configuration, such as T-type circuits, widely applied for PV inverters. This paper focuses on stress testing with a built-in characterization platform for easy and time-efficient characterization of T-type IGBT modules. First, state of the art in AC power cycling is presented. Second, the unique features of the stress testing platform are shown. Finally, the test result has been presented for the newly built platform.

I. Introduction

T-type power modules are a popular choice in Photovoltaic (PV) applications. According to PV power plant operators, the power electronics converter is responsible for most operation and maintenance (O&M) issues, ranging from 43% to 70% of service calls [1]. This emphasizes the critical need to assess power electronics' reliability in PV plants, as they can act as a bottleneck. Conducting a quantitative analysis of power module degradation can provide valuable insights into failure mechanisms and allow for more accurate lifetime assessment models.