###### Abstract  
In renewable and sustainable hydrogen production energy systems (RSHPES), the presence of harmonics gives rise to fluctuations in the voltage and current of the electrolysis cell (EC). This, in turn, results in an unstable electrolysis process, a reduction in hydrogen production efficiency, and an escalation in electrode corrosion. This paper puts forward a novel harmonic suppression control method (HSCM), which is devised for the single phase PWM rectifier in hydrogen production rectifiers (HPR) with the aim of alleviating the adverse impacts caused by harmonics. Initially, a highly meticulous harmonic model is constructed, which lays solid groundwork for understanding the existing problems. Subsequently, a comprehensive and detailed explanation of the HSCM is provided, accentuating its novel and inventive strategy for harmonic suppression. Thereafter, a comparison is drawn between the HSCM and traditional methods, thereby manifesting its enhanced suitability and superiority within the context of RSHPES. In conclusion, the simulation and experimental results vividly demonstrate the advantages, effectiveness, and practicality of HSCM under four conditions of power grids containing integer multiples of harmonics, interharmonics, ultraharmonics, and voltage disturbances. harmonic suppression control method; hydrogen production rectifier; renewable and sustainable hydrogen production energy systems +
Footnote †: journal: Applied sciences  
0000-0002-4000-3399-3399-3399-3399-3399-399-3999-3999-3999-3999-3999-3999-3999-3999-3999-3999-3999-3999-39999-3999-3999-3999-3999-3999-3999-3999-3999-3999-39999-3999-3999-3999-3999-3999-3999-3999-3999-3999-3999-3 have begun to investigate strategies for harmonic suppression through the control methods of the HPR. The topology of the HPR is shown in Figure 2.  
The HPR is composed of a PWM full-bridge rectifier and a phase-shift full-bridge converter. The HSCM is adopted in the PWM full-bridge rectifier. Because the HSCM aims to reduce the harmonic content in the input current, the phase-shift full-bridge converter can be ignored in this paper. Passive and active power filters are usually used for harmonic suppression. However, extra hardware will increase the system cost and the difficulty of operation and maintenance [13]. Therefore, digital filters have become the mainstream. A low pass filter is processed in Ref. [14] to solve the impact of the twice-frequency power pulsation of DC voltage; however, the bandwidth will be diminished. Ref. [15] introduces an additional resonant element to eliminate the third harmonic. However, control mechanisms that rely on small-signal linearized models may not guarantee stability across the entire operating range. The one-sampling-ahead-preview (OSAP) control scheme is used to suppress the harmonic in Ref. [16], although the harmonics of the AC bus will distort the reference current. Ref. [17] reduces the modulation level by reducing the output power. Therefore, the operating region is the linear modulation region. The distortion of the input current is avoided, but the efficiency decreases. A control strategy based on reactive power compensation is proposed. The power factor will be changed in this way [18; 19]. As solar panels and wind turbines become more prevalent, the harmonic content will also increase, causing greater damage to EC. The amplitude and phase of the harmonics will both increase. This could potentially lead to system instability. Therefore, suppressing harmonics is an urgent priority [20; 21]. At present, there is a plethora of research papers on harmonic suppression. However, few methods are capable of dealing with the ever-increasing harmonic content in RSHPES. Figure 1: The schematic diagram of the RSHPES. Figure 2: The topology of the HPR. In this paper, the author proposes a harmonic suppression strategy for the single-phase PWM rectifier (SPR) in HPR. The proposed method solves the influence of harmonics by eliminating the harmonics of AC bus current.