Parameter Optimization of Thyristor Snubber Circuit in LSTF Quench Protection System

Wei, Tianqi; Li, Hua; Fu, Peng; Song, Zhiquan; Wang, Kun; Wang, Shusheng; Zhang, Xiuqing

doi:10.1109/access.2019.2923442

Cited by 10 publications

(3 citation statements)

References 12 publications

(8 reference statements)

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“…A detailed multiobjective parameter optimization method was described in [17], which was used in this QPS thyristor stack snubber circuit design process. A diagram of the designed circuit and the design parameters are shown in figure 15 and table 6 respectively.…”

Section: A Study Of the Reverse Recovery Process Of The Thyristor Stackmentioning

confidence: 99%

100 kA/10 kV thyristor stack design for the quench protection system in CRAFT

Wei¹,

Meng²,

Li³

et al. 2023

Plasma Sci. Technol.

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Thyristors have longer lifetime, higher reliability, less maintenance and very high voltage and current rating capabilities compared to other high-power semiconductor devices. As a result, it is very suitable for Quench Protection System (QPS), which protects the superconducting magnet in large fusion device from being damage. In this paper, the design of a 100 kA/10 kV thyristor stack is proposed by both theorical and simulation analysis and experiment verification. Due to the ultra-high electrical performance requirements put forward by Comprehensive Research Facility for Fusion Technology (CRAFT) to QPS, three main issues must be considered: the voltage-balancing problem brought from multiple thyristors in series structure, the junction temperature rising problem brought from extremely high current and reverse recovery phenomenon as the thyristor physical structure. Hence, a series of detailed theoretical analyses, simulations and experiments including thyristor junction temperature prediction method and reverse recovery process modeling are carried out to optimize the design scheme. Finally, the reliability and stability of the thyristor stack are verified by a series of prototype experiments. The results verify the correctness and accuracy of the proposed design methods of the thyristor stack, and also indicate that the proposed thyristor stack can meet the application conditions of 100 kA QPS in CRAFT project.

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Section: A Study Of the Reverse Recovery Process Of The Thyristor Stackmentioning

confidence: 99%

100 kA/10 kV thyristor stack design for the quench protection system in CRAFT

Wei¹,

Meng²,

Li³

et al. 2023

Plasma Sci. Technol.

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“…Series connected thyristors in the outgoing valve are represented by an integrated current source i r (t), for which the thyristor turn-off model in exponential form is adopted. The method proposed in [23] is used for parameter extraction. Moreover, a simplified circuit can be derived under the assumption that the transformer phase not included in the commutation process (phase c here) carries negligible current and has no effect on the turn off process [24], as shown in Figure 2c.…”

Section: The Conventional Low Frequency Modelmentioning

confidence: 99%

Analysis and Design of Damping Circuit Parameters for LCC Valves Based on Broadband Model

Tang

Zhang

2020

Energies

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Damping circuits are installed inside the converter valve to limit commutation overshoots. They have significant effects on the valve’s turn-off performances, which should be carefully considered in parameter design. First, the calculation models for the turn-off process are discussed, including the conventional low frequency model and the broadband model. Then, it is found that high-frequency equipment parameters have significant effects on the transient valve voltage, which means that the conventional analytical methods based on low-frequency models is not suitable for damping circuit parameter design. The relationships between the turn-off performances and damping circuit parameters have also been analyzed in detail with the broadband model. To achieve better economic efficiency, this paper proposes a novel method for damping circuit parameter optimization, which combines the electromagnetic transient (EMT) calculation and the numerical optimization. Last, the case study is carried out based on a practical ±1100 kV ultra-high-voltage direct-current (UHVDC) transmission project, which proves the reliability and flexibility of the proposed method.

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“…In ITER, the mechanical switch and thyristor in parallel with the counter-pulse network are employed in the quench protection system called fast discharge unit (FDU) [7]. For CFETR, investigations about the quench protection unit are still in the process [8][9][10][11][12]. With the demand of the high reliability and simple for construction, the mature solution of fuse-based commutation, which has been employed in EAST and LHD, is more applicable [13,14].…”

Section: Introductionmentioning

confidence: 99%

A commutation analytical model for quench protection of the CFETR central solenoid model coil

Deng

Gao

et al. 2020

Plasma Sci. Technol.

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A central solenoid model coil will be set up to develop and verify the technique for the full-size central solenoid coil of the China Fusion Engineering Test Reactor. In case of quench and failures of superconducting coils, the quench protection (QP) system, which employs fuse-based commutation technology, is designed. This paper presents an analytical model to investigate the commutation process in the QP circuit. The model consists of the QP circuit equations, the breaker arc model, the fuse pre-arc model, and the fuse arc model. The model is employed in the whole commutation process including current transfer from breaker branch to the fuse branch model, then from fuse branch to the discharge resistor branch, and current decrease to zero in the discharge resistor. The experiment result verified the effectiveness of the presented model. The model might be helpful for design of the fuse and optimization of the commutation circuit.

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Parameter Optimization of Thyristor Snubber Circuit in LSTF Quench Protection System

Cited by 10 publications

References 12 publications

100 kA/10 kV thyristor stack design for the quench protection system in CRAFT

100 kA/10 kV thyristor stack design for the quench protection system in CRAFT

Analysis and Design of Damping Circuit Parameters for LCC Valves Based on Broadband Model

A commutation analytical model for quench protection of the CFETR central solenoid model coil

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