Open Access

ARTICLE

Research on Excitation Power Supply Suitable for Total Harmonic Distortion Analysis (THDA) Detection of Hydrogen Production Equipment

Xian Li¹, Bo Zhao^1,*, Min Liu², Qiliang Wu²
1 School of Automation, Beijing Information Science and Technology University, Beijing, China
2 Energy Storage Technology Research Laboratory, State Grid Zhejiang Electric Power Research Institute, Hangzhou, China
* Corresponding Author: Bo Zhao. Email:

Energy Engineering https://doi.org/10.32604/ee.2026.085562

Received 13 May 2026; Accepted 13 July 2026; Published online 29 July 2026

Abstract

Total Harmonic Distortion Analysis (THDA) can precisely characterize internal performance degradation and fault evolution in electrolyzers, making it a key online condition-monitoring tool for improving overall energy efficiency and ensuring the extended lifespan of hydrogen production systems. THDA detection of hydrogen production equipment requires the injection of wideband perturbation signals across a wide frequency band (0.1 Hz–100 kHz) under a strong direct current (DC) bias. Traditional monolithic converters face significant challenges in balancing large-capacity DC output with wideband perturbation injection due to severe switching losses. To overcome this limitation, this paper proposes a broadband, high-dynamic-excitation power-supply solution based on a dual-power-supply parallel architecture with alternating current/direct current (AC/DC) impedance decoupling. At the hardware level, an improved bidirectional half-bridge topology with multi-level series matching inductors is proposed. Relying on the high-frequency passive low-pass filter network composed of a series inductor and an electrolyzer and the high-impedance isolation characteristics of the inductor current, this topology realizes the transient impedance decoupling of AC/DC parallel nodes while suppressing the chopping ripple of high-frequency switching, and blocks the current backflow caused by DC bus voltage disturbance. At the control level, a two-layer adaptive control strategy based on steady-state feature extraction is proposed for the characteristics of equivalent impedance drift of the electrolyzer under broadband sweep. This strategy relies on the discrete Fourier transform (DFT) to extract fundamental error features, introduces a nonlinear dead zone and anti-saturation mechanism, and realizes cross-decoupling and dynamic optimization of control parameters. Simulink simulation and STM32 hardware physical platform test results show that under conditions such as 0.1 Hz–100 kHz wideband steady-state scanning, cross-band stepping, and DC side disturbances, the system achieves millisecond-level dynamic response in the mid-to-high frequency band. In digital simulation, the full frequency band current Total Harmonic Distortion (THD) is strictly below 3%. In the hardware prototype tests, the fundamental amplitude steady-state tracking error is strictly controlled within 3%; The output current THD is below 2% within the core frequency band of 10 Hz–1 kHz, while in the edge frequency range (0.1 Hz–10 Hz and >1 kHz), due to hardware nonlinear constraints, it is as high as about 12%. This demonstrates the feasibility and effectiveness of the proposed research protocol.

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Keywords

Hydrogen production equipment; THDA detection; broadband excitation power supply; improved bidirectional half-bridge; steady-state feature extraction; adaptive control

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