The “Sentinel” Safeguarding High-Reliability Hydrogen Energy Testing — N1200 Series Voltage Monitoring Instrument

As the global energy structure transitions toward low-carbon and clean energy solutions, hydrogen energy has emerged as a highly promising energy carrier. Its industrial chain is accelerating across both technological development and commercialization. Among these, fuel cells and water electrolysis hydrogen production systems (electrolyzers) represent the two core pillars of hydrogen-based “power generation” and “hydrogen production.”

In both applications, the stack is the core component. Its performance, service life, and safety directly determine the overall system’s success or failure. Accurately, rapidly, and reliably monitoring the voltage of hundreds or even thousands of individual cells within a stack is a critical requirement throughout R&D, manufacturing, testing, and operation & maintenance.

Testing Bottlenecks in the Hydrogen Industry: Technical Challenges of Voltage Monitoring

Both fuel cell stacks and electrolyzer stacks are constructed by connecting dozens to thousands of individual cells in series to achieve the required high voltage and high power output. While this series-stacking structure enables energy aggregation, it introduces unprecedented challenges for accurate voltage measurement.

Hydrogen fuel cell

Water electrolyzer

During fuel cell operation, the voltage of each individual cell—typically between 0.5 V and 1.0 V—is the most direct and sensitive indicator of cell health. Voltage abnormalities such as undervoltage, polarity reversal, or inconsistency directly signal performance degradation, localized failure, or even catastrophic faults. Therefore, real-time, synchronous, and high-precision voltage monitoring of every single cell is essential.

Common-Mode Voltage (CMV) Suppression

When measuring a cell located near the top of the stack, its small differential voltage (approximately 0.8 V) is superimposed on a very high common-mode voltage relative to the test system ground. Excessive common-mode voltage may damage measurement equipment and severely degrade measurement accuracy, making CMV suppression a fundamental technical challenge.

Harsh Electromagnetic Environment

Hydrogen energy test benches typically include high-power electronic loads, power supplies, and inverters. These devices generate strong electromagnetic interference (EMI) during operation. Such harsh electromagnetic environments can significantly disturb voltage sampling stability, resulting in large fluctuations in measured data.

High-Speed Parallel Acquisition Across Large Channel Counts

Traditional scanning or polling-based measurement methods switch channels sequentially, introducing inherent time delays. When hundreds of channels are scanned, the time difference between the first and last channel can reach tens or even hundreds of milliseconds. Under fast-changing dynamic conditions, such asynchronous data becomes invalid, failing to reflect the instantaneous internal state of the stack and rendering it unsuitable for precise fault diagnosis or modeling.

NGI High-Performance Voltage Monitoring Solution

Leveraging long-term research and practical experience in the hydrogen energy industry, NGI has developed the N1200 Series multi-channel high-performance voltage monitoring instrument. Through a modular isolation architecture, the N1200 effectively addresses the challenge of high common-mode voltage. By applying FPGA-based parallel control technology, it achieves a major breakthrough in high-speed parallel data acquisition. In addition, industrial-grade reliability design ensures dependable operation in complex test environments.

Together, these three core technologies establish the N1200 Series as an indispensable professional solution for hydrogen energy testing, widely applicable to electrolyzer and fuel cell stack voltage monitoring.

High Accuracy with Strong Common-Mode Voltage Immunity

The N1200 Series adopts a modular grouped acquisition and multi-level isolation architecture, electrically dividing a high-voltage stack into multiple low-voltage “cell groups.” Each group is managed by an independent front-end acquisition module, fundamentally resolving common-mode voltage challenges in the hundreds to thousands of volts range.

A very high common-mode rejection ratio (CMRR) is the key enabler of high-precision measurement, effectively suppressing noise and fluctuations superimposed on the common-mode voltage and ensuring measurement accuracy.

Withstanding Complex EMI for Maximum Reliability

Magnetic coupling interference generated by high-voltage power cables is typically superimposed on signal lines in the form of common-mode noise, leading to significant voltage data fluctuations.

The N1200 Series employs modular electrically isolated front-end sampling units combined with differential signal processing (instrumentation amplifiers), delivering exceptional immunity to EMI and common-mode noise while amplifying only the pure differential voltage—namely, the individual cell voltage.

High-Speed Parallel Acquisition for Large-Scale Channels

The N1200 Series abandons traditional multiplexed switching or centralized ADC polling architectures. Instead, it innovatively utilizes a large-scale FPGA as the core controller. Digital data converted by front-end acquisition units is transmitted independently and in parallel to the FPGA via dedicated digital isolators.

This architecture enables true parallel sampling, allowing up to 200 channels to be acquired and refreshed within 10 ms. Engineers can therefore capture the voltage status of all cells at the same instant, providing a robust data foundation for dynamic performance analysis and precise consistency evaluation.

Looking Ahead

As hydrogen energy technologies continue to evolve, voltage monitoring requirements will become even more demanding. Future challenges include higher-voltage stacks (>1500 V), faster dynamic response (higher sampling rates), and deeper data fusion with other physical parameters such as temperature, pressure, and impedance.

With years of accumulated industry testing expertise and a comprehensive portfolio of fuel cell testing instruments, NGI is well positioned to provide diversified testing products and professional hydrogen energy testing solutions, continuously delivering solid and reliable data foundations for the advancement of the hydrogen energy industry.