243 / 2024-06-30 11:52:59

Study on an Innovative Permanent Magnet Trip Device for DC Miniature Circuit Breakers

miniature circuit breaker,permanent magnet tripping device, dynamic and static characteristics, simulation analysis

In recent years, with the rapid development of low-voltage power systems, the demand for the performance of low-voltage switching devices has also shown a growing trend. As a switching device widely used in low-voltage areas, the miniature circuit breaker has demonstrated excellent performance in circuit short-circuit protection, playing a crucial role in ensuring the stability and safe operation of the power system. Among them, the magnetic tripper, as a key component for realizing instantaneous tripping actions in short-circuit protection, has a direct impact on the protection effect of the miniature circuit breaker in terms of its performance and reliability. Therefore, research on magnetic trippers is of great significance for improving the short-circuit protection performance of miniature circuit breakers.

This article focuses on the study of a permanent magnet tripper used in DC miniature circuit breakers, which adopts a scheme of setting a permanent magnet opposite to the moving iron core to replace the traditional tripper built-in spring scheme. The three-dimensional modeling software is used to establish a virtual prototype simulation model of the permanent magnet tripper. Based on national standards, the coil current is set to three times the rated current as a constraint condition for non-action. Through virtual simulation software, the shape and size of the permanent magnet and the relative position of the permanent magnet and the moving iron core are determined. The action process of the permanent magnet tripper is simulated and calculated, and the dynamic and static characteristic curves of the permanent magnet tripper are obtained. Key parameters such as electromagnetic suction force and tripping time are analyzed in detail, and a thorough comparison is made with traditional tripper. The comparison of simulation results between the two shows that when a short-circuit current occurs in the circuit, the permanent magnet tripper can perform tripping actions accurately and quickly in a shorter time compared to traditional tripper, ensuring the efficient and stable operation of the miniature circuit breaker and quickly and effectively cutting off the faulty circuit.

In order to further verify the accuracy of the simulation calculation, the instantaneous tripping test is carried out on the miniature circuit breaker equipped with permanent magnet tripping device and traditional tripping device.The repeated test results show that under the same short-circuit current condition, the permanent magnet tripper can trigger the tripping action more quickly than the traditional tripper, has obvious advantages in the tripping time, and shows higher action stability, which can effectively realize the protection of the circuit and prevent the short-circuit current from causing further damage to the power system.