A Control Strategy Based on Small Signal Model for Three-Phase to Single-Phase Matrix Converters

Chen, Si,Ge, Hongjuan,Zhang, Wenbin,Lu, Song The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

Two-level fault diagnosis RBF networks for auto-transformer rectifier units using multi-source features

Lin, Yi,Ge, Hongjuan,Chen, Shuwen,Pecht, Michael The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.3

The auto-transformer rectifier unit (ATRU) is one of the most widely used avionic secondary power supplies. Timely fault identification and location of the ATRU is significant in terms of system reliability. A two-level fault diagnosis method for the ATRU using multi-source features (MSF) is proposed in this paper. Based on the topology of the ATRU, three key electrical signals are selected and analyzed to extract appropriate features for fault diagnosis. Mathematic expressions and simulation results of the feature signals under different fault modes are presented in the paper. Therefore, a unique MSF system is developed and a two-level fault diagnosis method based on radial basis function network groups is proposed. On the first level, the overall fault set is classified into three subsets and then on the second level, three radial basis function neural networks are constructed and trained to realize accurate fault localization. To verify the diagnosis performance of the proposed method, several comparative tests are implemented on a 12-pulse ATRU system, which shows that this method has a lower computational cost, better diagnostic accuracy and increased stability when compared with alternative methods.

Research on a New 12-Pulse Step-Up and Step-Down Aviation Auto-Transformer Rectifier

Fan Jiang,Hongjuan Ge,Xiao-xu Dong,Lu Zhang 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

This paper presents a new step-up and step-down multi-pulse auto-transformer rectifier unit (ATRU) topology. This structure can achieve a wide range of output voltages, which solves the problem of auto-transformer output voltage being difficult to regulate. Adding middle taps to the primary winding and reasonably setting the number of auto-transformer windings, constituted two groups of three-phase output voltages with a 30° phase difference. Multi-pulse output DC voltage is obtained after a three-phase output voltage across two rectifier bridges and inter-phase reactor. Thus, the output DC voltage is related to the number and configuration of the auto-transformer winding. In this paper, the relationship between the voltage ratio of the auto-transformer and the ratio of winding, input current and auto-transformer kilovoltampere rating are deduced and validated by simulations. On this basis, the output voltage range is optimized. An experiment on two different voltage ratio principle prototypes was carried out to verify the correctness of the analysis design.

Family of Dual-Input Dual-Buck Inverters Based on Dual-Input Switching Cells

Fan Yang,Hongjuan Ge,Jingfan Yang,Runyun Dang,Hongfei Wu 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

A family of dual-DC-input (DI) dual-buck inverters (DBIs) is proposed by employing a DI switching cell as the input of traditional DBIs. Three power ports, i.e. a low voltage DC input port, a high voltage DC input port and an AC output port, are provided by the proposed DI-DBIs. A low voltage DC source, whose voltage is lower than the peak amplitude of the AC side voltage, can be directly connected to the DI-DBI. This supplies power to the AC side in single-stage power conversion. When compared with traditional DBI-based two-stage DC/AC power systems, the conversion stages are reduced, and the power rating and power losses of the front-end Boost converter of the DI-DBI are reduced. In addition, five voltage-levels are generated with the help of the two DC input ports, which is a benefit in terms of reducing the voltage stresses and switching losses of switches. The topology derivation method, operation principles, modulation strategy and characteristics of the proposed inverter are analyzed in-depth. Experimental results are provided to verify the effectiveness and feasibility of the proposed DI-DBIs.

Family of Dual-Input Dual-Buck Inverters Based on Dual-Input Switching Cells

Yang, Fan,Ge, Hongjuan,Yang, Jingfan,Dang, Runyun,Wu, Hongfei The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

A family of dual-DC-input (DI) dual-buck inverters (DBIs) is proposed by employing a DI switching cell as the input of traditional DBIs. Three power ports, i.e. a low voltage DC input port, a high voltage DC input port and an AC output port, are provided by the proposed DI-DBIs. A low voltage DC source, whose voltage is lower than the peak amplitude of the AC side voltage, can be directly connected to the DI-DBI. This supplies power to the AC side in single-stage power conversion. When compared with traditional DBI-based two-stage DC/AC power systems, the conversion stages are reduced, and the power rating and power losses of the front-end Boost converter of the DI-DBI are reduced. In addition, five voltage-levels are generated with the help of the two DC input ports, which is a benefit in terms of reducing the voltage stresses and switching losses of switches. The topology derivation method, operation principles, modulation strategy and characteristics of the proposed inverter are analyzed in-depth. Experimental results are provided to verify the effectiveness and feasibility of the proposed DI-DBIs.

A Control Strategy Based on Small Signal Model for Three-Phase to Single-Phase Matrix Converters

Si Chen,Hongjuan Ge,Wenbin Zhang,Song Lu 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

Improved SVPWM modulation method for three‑phase dual‑input dual‑buck inverters

Yongshuai Wang,Hongjuan Ge,Hang Yin,Bingjie Wu,Fan Yang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5

The traditional modulation method for three-phase dual-input dual-buck inverters is level-shifted sine pulse width modulation. The disadvantage of this method is that the dc voltage utilization ratio is low and the software fault tolerance is difficult to realize. To solve these problems, an improved SVPWM suitable for this inverter is proposed in this paper. By analyzing the switch modes and bridge arm midpoint level of this inverter, 27 voltage vectors are obtained. According to the obtained long vector cluster, medium vector cluster, and short vector cluster, six modulation sectors are obtained, and each modulation sector has four modulation regions. When the voltage of the inverter low-voltage dc source changes, the associated vector changes as well. How the modulation region changes when the associated vector changes is analyzed. The action time of each vector in each modulation region is deduced. In addition, the action order of each vector involved in vector synthesis is optimized. A 2 kW prototype was built to carry out experimental research. Experimental results show that this modulation method improves the dc voltage utilization ratio, reduces the loss, and improves the efficiency of the inverter.

Risk assessment of aviation DC series arc based on reconstructed CBAM‑CNN

Haoqi Yang,Cong Gao,Hongjuan Ge,Yiqin Sang,Yongshuai Wang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5

The hazards of sustained arc and un-sustained arc are different. However, during the stage of arc development, there is a lack of effective methods to identify them, which is not conducive to the timely accurate assessment of arc risk. Therefore, this paper proposes a risk assessment method for aviation DC series arc based on a reconstructed CBAM-CNN. First, in the process of generating the feature set, a feature evaluation function is defined to screen the features. Then the existing convolution block attention module (CBAM) is improved by adding a reshaped layer and redefining spatial attention, which results in the reconstructed CBAM-CNN. Finally, the reconstructed CBAM-CNN takes the feature set as its input and output arc risk assessment results on the basis of enhancing the attention of important features. The validity of the reconstructed CBAM-CNN method is verified on an aviation DC arc generation platform. It is found that the proposed method has a higher training efficiency and evaluation accuracy than the CNN method and CBAM-CNN method. In addition, the reconstructed CBAM-CNN involves fewer parameters to be measured, which can reduce its dependence on computing resources.

Unbalance Control Strategy of Boost Type Three-Phase to Single-Phase Matrix Converters Based on Lyapunov Function

Yu-xiang Xu,Hongjuan Ge,Hai Guo 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

This paper analyzes the input side performance of a conventional three-phase to single-phase matrix converter (3-1MC). It alsopresents the input-side waveform quality under this topology. The suppression of low-frequency input current harmonics isstudied using the 3-1MC plus capacitance compensation unit. The constraint between the modulation function of the output andcompensation sides is analyzed, and the relations among the voltage utilization ratio and the output compensation capacitance,filter capacitors and other system parameters are deduced. For a 3-1MC without large-capacity energy storage, the systemperformance is susceptible to input voltage imbalance. This paper decouples the inner current of the 3-1MC using a Lyapunovfunction in the input positive and negative sequence bi-coordinate axes. Meanwhile, the outer loop adopts a voltage-weightedsynthesis of the output and compensation sides as a cascade of control objects. Experiments show that this strategy suppressesthe low-frequency input current harmonics caused by input voltage imbalance, and ensures that the system maintains good staticand dynamic performances under input-unbalanced conditions. At the same time, the parameter selection and debugging methodsare simple.