Analysis Of Parasitic Parameters In The External Bypass Cabinet Based On PEEC Theory

ITER external bypass cabinet is an important equipment that protect from over-current and over-voltage in the rectification power supply system. In the worst case, the maximum peak pulse current may reach about 300kA. So, it need parallel branch to share the current. During the operation of power electronic devices with parallel branch, because of the parasitic parameters in the external bypass cabinet, the current sharing of parallel branch would be far from the satisfaction, so the entire operation of equipment would have impact from overload devices. In order to increase the stability and reliability of the operation of the equipment parasitic parameters of the devices should be arranged in a reasonable range. And partial element equivalent circuit (PEEC) is an effective circuit modeling and parameter extraction method. This paper establishes relatively accurate circuit model of external bypass cabinet based on PEEC method, and proposes the improved measures in consideration of current sharing1)This paper gives the principle of partial element equivalent circuit and ideas for improvement. Modified nodal equation (MNA) which is to describe the system takes place of a specific equivalent circuit. Partial element equivalent circuit method is applied to the analysis of parasitic effect of single-layer PCB in the Matlab environment. And it shows the validation of the correctness of the numerical results with analytical method.2)Based on the original design, it gives the circuit modeling and the calculation of parasitic parameters of external bypass using PEEC method. After simulation and qualitative control experiments, the results have been verified.3)It proposed some improvements of external bypass cabinet considering of the current sharing, including adjustment of the distance between each branch, establishment of a symmetrical cylindrical external bypass cabinet, the use of series reactor and laminated power bus,.