MLPE Testing Facility

As photovoltaic systems increasingly rely on Module-Level Power Electronics (MLPE)—such as microinverters, DC power optimizers, and rapid shutdown devices—ensuring their long-term reliability has become a critical industry focus. The ASU Photovoltaic Reliability Laboratory (PRL) features a dedicated MLPE testing infrastructure designed to evaluate the performance, durability, and degradation mechanisms of these devices. Because MLPEs are typically mounted directly to the back of PV modules, they are subjected to extreme microclimates, making rigorous reliability assessments essential.

Our facility leverages ASU PRL’s extensive Accelerated Stress Testing (AST) capabilities to push MLPE devices to their physical and electrical limits. Inside our state-of-the-art environmental chambers, devices undergo severe thermal cycling (from -60°C to 150°C) and damp heat exposure while under active electrical loads. We specialize in evaluating MLPEs using both fixed and cyclic power stresses at elevated temperatures, allowing our researchers to accurately simulate years of harsh field conditions in a matter of months. This highly controlled indoor testing helps identify specific failure modes, thermomechanical fatigue, and electronic component vulnerabilities.

In addition to indoor accelerated testing, the MLPE facility conducts comprehensive outdoor field evaluations at our Mesa, Arizona test site. This real-world exposure allows our researchers to monitor devices operating in a true hot-dry desert climate. Our field studies encompass continuous performance monitoring, thermal gradient mapping, and evaluating the combined effects of module soiling and MLPE reliability. By bridging the gap between rigorous indoor accelerated lifetime testing and long-term outdoor field data, the ASU PRL provides manufacturers and researchers with vital insights to optimize the next generation of power electronics.

Our MLPE Testing Capabilities

The Module-Level Power Electronics (MLPE) test facility at the ASU Photovoltaic Reliability Laboratory (ASU-PRL) is a specialized, high-capacity testing infrastructure dedicated to evaluating the long-term reliability, performance, and thermal endurance of microinverters and DC power optimizers.

Here are the key capabilities and features of the ASU-PRL MLPE testbed:

High-Volume Testing Capacity: The facility is equipped to simultaneously stress-test up to 80 MLPE devices. This is achieved using a battery of eight dedicated thermal convection ovens (instead of walk-in environmental chambers), with each oven capable of accommodating up to 10 MLPE units at a time.
Energy-Efficient Closed-Loop Architecture: To evaluate units under full operational load without destabilizing the local grid, the lab utilizes a unique "power recycling" circuit. The AC power output of the microinverters is fed directly back into their own DC power supplies. This means additional grid power is only drawn to compensate for minor circuit losses, which drastically reduces total energy consumption and heat dissipation compared to using standard resistor banks or grid simulators.
Independent High-Fidelity Monitoring: Relying on the built-in sensors of MLPE devices during extreme stress testing can lead to data errors if the device itself begins to degrade. To ensure absolute accuracy, ASU-PRL utilizes a dedicated, external network of relays in conjunction with Hall effect and precision voltage sensors to continuously measure DC input (VDC, IDC) and AC output parameters (VAC, IAC, IRMS, PAC, etc.).
Dynamic Thermal and Power Cycling: The testbed simulates severe, real-world operational stress by subjecting MLPEs to either constant or cyclic power loads (e.g., 6 cycles per day at 4-hour intervals). The ovens dynamically adjust the ambient temperatures to precisely maintain specific internal device targets—such as 65°C to 75°C—actively compensating for the internal heat generated by the devices' own efficiency losses.
Continuous Lifetime Tracking: Thermal and electrical performance data are continuously monitored and recorded in real-time for all units in the testbed. This allows researchers to accurately map degradation curves, understand operational vulnerabilities, and pinpoint the exact time-to-failure for each individual device.