Study on the failure rate of high-power thyristors irradiated by artificial neutron irradiation under different DC bias voltages

Abstract

High-voltage semiconductor devices such as thyristors, due to the high voltage applied, when encountering atmospheric neutrons in the operating state, may appear single event burnout due to charge multiplication in high-altitude areas. The atmospheric neutron radiation in high-altitude areas can cause damage and interference to semiconductor devices, which seriously threatens their safe operation. However, there is little research on the influence of atmospheric neutron irradiation on the operating life of high-voltage DC transmission system thyristors in high-altitude areas. Therefore, in this paper, the neutron beam of the Atmospheric Neutron Irradiation Spectrometer (ANIS) of China Spallation Neutron Source (CSNS) was used to irradiate the high-power thyristors. The failure rates of different applied voltages under 6.74 × 106 n/cm2/s neutron flux irradiation and the leakage current changes during irradiation were obtained. The failure rate applied voltage relationship curve obtained from the artificial neutron irradiation experiment was converted to the corresponding value in Yangbajing area, China. Through the results of the artificial neutron accelerated irradiation experiment, the thyristor failure rate-voltage formula in different areas can be more accurately estimated. In this way, the reasonable working voltage can be determined according to the operating life demand of the thyristor, and determine the thyristor configuration scheme of the design of the converter station. In addition, it is found that the leakage current of thyristor increases with the increase of neutron irradiation time, which may eventually lead to the degradation of thyristor performance and affect its reliability in the DC transmission system.

Keywords

• UHVDC transmission
• Neutron irradiation
• Thyristor
• Bias voltage
• Failure rate
• Leakage current