Chaotic ant colony algorithm‑based frequency‑optimized random switching frequency SVPWM control strategy

Siyan Zhang,Xudong Wang,Kai Zhou,Xuan Shao,Jinfeng Liu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.11

To solve the problem where the space vector pulse width modulation (SVPWM) of a three-phase inverter produces large harmonic components near the switching frequency (fs) and its doubling frequency, a frequency-optimized random switching frequency SVPWM (FORSF-SVPWM) control strategy is proposed in this paper. In this strategy, the basic principle of the chaotic ant colony algorithm in path optimization is used to determine the optimized scheme of the switching frequency distribution in the FORSF-SVPWM. Research shows that the frequency sample formed by the sigmoid function curve in the switching frequency range can cause the energy that was originally concentrated on the switching frequency and its doubling frequency to be more evenly distributed in the whole frequency range. Moreover, the amplitude of each harmonic wave is shown to be suppressed. The proposed strategy reduces the high-frequency noise and conducted electromagnetic interference (EMI) existing in power switching circuits. Thus, this strategy is obviously better than the traditional random switching frequency SVPWM (RSF-SVPWM) algorithm with its approximately uniform frequency distribution. Simulation and experimental results show that this strategy can work well in the hardware platform of a three-phase inverter without changing the topology of the main circuit of the system. In addition, this strategy is easy to implement.

SVPWM Overmodulation Region II Control Method Based on the Chaos Ant Colony Algorithm

Zhang Siyan,Wang Xudong,Gao Junshan,Wu Xiaogang,Liu Jinfeng 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

The control method of space vector pulse width modulation (SVPWM) overmodulation region II has the disadvantages of a complicated process and large harmonic content. To solve these problems, this paper proposes an SVPWM overmodulation region II control method based on the chaos ant colony algorithm. Since the multiple control of the rotation angle ( θ ) in the SVPWM algorithm will bring about diff erent implementation eff ects, this paper uses the chaotic ant colony algorithm to optimize the control process of θ in overmodulation region II and summarizes the θ equations in each sector to achieve the goal of suppressing the total harmonic distortion ( THD ) in the output voltage vector. Simulation and experimental results demonstrate that this method makes the amplitude of the output voltage vector relatively continuous, thereby avoiding the harmonic content caused by the voltage jump of the traditional algorithm in overmodulation region II.

Novel Dead-time Segmented Compensation Strategy for a Wide Impedance Angle Range in a Three-phase Inverter with a Resistance-Inductance Load

Zhang Siyan,Wang Xudong,Ma Junjie,Duan Ruizhen,Zhou Kai 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

The dead-time setting in space vector pulse width modulation (SVPWM) causes inverter output waveform distortion and performance degradation. This paper proposes a novel dead-time segmented compensation strategy for a wide impedance angle range in a three-phase inverter with a resistance-inductance load. Since the load impedance angle ( φ ) of the threephase inverter produces diff erent dead-time eff ects, in this paper, it is divided into two intervals of [0 30°] and [30° 90°] and a corresponding dead-time segmented compensation strategy is proposed, which solves the limitation of the traditional time compensation scheme that analyzes only the resistive load. In addition, this paper uses the conversion relationship between the power factor ( λ ) and φ to determine the current polarity of each sector in the vector space, which avoids the detection error of the current zero-crossing point in the traditional compensation scheme. The simulation and experimental results demonstrate that this method eff ectively reduces the total harmonic distortion (THD) of the inverter output current signal by approximately 30% and is easy to program, which improves the inverter output performance.

Study on the Influence of Stiffeners on the Wind Resistance Performance of Aluminum Panel Curtain Wall

Cun Hui,Siyan Wang,Mingliang Liu,Weichi Han,Ran Hai 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.4

In order to study the infl uence of stiff eners on the wind resistance performance of the aluminum panel curtain wall unit (APCU), two APCU specimens with diff erent structures were designed and fabricated. The deformations under positive and negative wind loads were studied. The defl ection, stress, and mode were analyzed by fi nite element software. The results indicate that the stiff eners and the aluminum panels work well with each other under positive and negative wind pressure. Adequately designed stiff eners can eff ectively improve the wind resistance of the APCU, reduce the deformation of the aluminum curtain wall, and make the stress distribution uniform. The shedding of aluminum welding nails has a signifi cant impact on the overall wind resistance performance of the component. The aluminum panels and the stiff eners reduce the wind resistance performance of the APCU when the aluminum panels and stiff eners are not fi rmly connected. The modal analysis points out the weak point of the specimens. The fi nite element calculations and analysis results are consistent with the actual measurement results. The research results can guide engineering applications. The research in this paper can provide guidance for wind resistance of aluminum plate, defl ection deformation of stiff ening rib, failure of aluminum plate under wind pressure and engineering research of aluminum curtain wall system under wind load.

Three‑phase four‑level inverter with capacitor voltage self‑balancing and high DC‑voltage conversion ratio

Bihua Hu,Fa Wang,Jiang Zhu,Wenlang Deng,Zhaohong Wang,Siyan Liu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5

Multilevel inverters are widely employed in industry application due to their low voltage-variation rate and little current distortion. However, capacitor-voltage regulation adds the complexity of their modulation, and the low DC-voltage conversion ratio restricts their application in some specific occasions. Here, a new three-phase four-level inverter with switchedcapacitor circuits and full-bridge circuits is proposed to address the above issues. In addition, a corresponding space-vector diagram is proposed to control the power switches of the inverter. In this space-vector diagram, each subsector includes only a switching sequence, which is simpler than the conventional one. Then, simulation and experimental platforms are established to demonstrate the validity of the proposed inverter. The obtained results show that the proposed inverter can meet the expected design requirements.

Selection and evaluation of reference genes for quantitative gene expression analysis in broomcorn millet (Panicum miliaceum L.)

Hong Yue,Pingchuan Deng,Siyan Liu,Meng Wang,Weining Song,Xiaojun Nie 한국식물학회 2016 Journal of Plant Biology Vol.59 No.5

The appropriate reference genes are crucial for normalization of the target gene expression in qRT-PCR analysis. Broomcorn millet (Panicum miliaceum L.) is one of the most important crops in drought areas worldwide, while the systematical investigation and evaluation of reference genes has not been investigated in this species up to now. Here, 9 commonly used reference genes were selected to detect their expressional stability in different tissues and under different stresses in broomcorn millet. ΔC t , BestKeeper, NormFinder and GeNorm approaches were used to evaluate the potentiality of these candidate genes as the reference gene in broomcorn millet. Taken together, results found that 18S and GAPDH were the suitable reference genes for gene expression normalization in different tissues and under stress treatment in broomcorn millet. This was the first study to investigate the reference genes for qRT-PCR analysis in broomcorn millet, which will facilitate the gene expression studies and also accelerate revealing the molecular mechanism of well-adapted extreme climatic conditions.