Portable device with mobile phone connectivity for real-time solar module characterization – pv magazine International

September 6, 2024 Emiliano Bellini

A Colombian research group has designed a new portable electronic device that allows on-site measurement of the IV and PV curves of photovoltaic panels, competing with similar but more expensive and difficult-to-use technologies available on the market.

The new vehicle features a 240 MHz Tensilica LX6 dual-core processor and 4 MB storage memory. It works by collecting data on solar radiation, ambient temperature, electric current and voltage signals from PV panels via a mobile app on a mobile phone.

“When the collected data is synchronized with a server, it becomes accessible from anywhere and enables analysis using data analytics algorithms and Machine Learning,” the team explained. “This enables the creation of predictive models and the detection of deficiencies in the system by identifying individual components such as end-of-life and poor positioning.”

For the experimental device, the researchers used an ESP32 microcontroller from US-based SparkFun Electronics. “It has a WiFi module that can connect to mobile devices,” they said. “It has 28 GPIO pins and also provides support for low-energy Bluetooth connections. The versatility of ESP32 shines in IoT project execution.”

As for the sensors, the device uses an ACS712 current sensor, a voltage divider consisting of two resistors in series, an NTC 10K temperature sensor, and an SP Lite2 irradiance sensor. It also uses a switching boost module XL6009 as a voltage regulator and an ADS1015 module as an analog-to-digital converter. Moreover, it includes a p-type MOSFET transistor for high-frequency switching, cables and batteries for energy storage.

“ESP32 serves as the central device in the printed circuit board (PCB) design where all input and output signals converge,” the scientists explained. “Each signal has its own filtering stage. Since the maximum output of ESP32 is 3.3 V, it is opto-coupled to pass the signal at 7.4 V, which exceeds the gate-to-source voltage (VGS) required for proper switching.”

The system also has a casing that can be certified to withstand IP55 or higher standards, the researchers say.

The performance of the portable instrument was tested in two different geographical locations and for two different types of photovoltaic panels. The measurements were taken at different times of the day to ensure that the curves were drawn at different radiations. The tests showed that the proposed system can provide results compatible with traditional instruments.

“By using low-cost components such as microcontrollers and digital signal processors (DSPs), the development of our photovoltaic performance monitor has revealed valuable economic benefits,” the academics emphasized. “This approach significantly increases the cost-effectiveness and accessibility of PV systems by reducing the overall expense required for monitoring.”

The group estimated the cost of the experimental device and found it could range from $1,000 to $1,200, and said more advanced systems in the future could even cost between $275,000 and $630,000.

Details of the system can be found in the “Study”.Design and implementation of an autonomous device with an application for monitoring the performance of photovoltaic panels” It was published Energy Reports.

“The compact structure of the device allows expansion in future versions with new functions such as characterization of power generation systems or enhancement of signals with signal processing-oriented electronics, and obtaining quality certification according to established standards,” the group said.