Coupling Path Identification of Conducted EMI in a High-Voltage Discharging Circuit Using Near-Field Scanning

Electromagnetic interference (EMI) problems are common and can severely affect the normal function of high-voltage discharge circuits. This paper investigates the EMI issue in a dual-channel high-voltage discharge system, where the high-voltage discharging current of one circuit causes the false triggering of the other low-voltage triggering circuit. To effectively analyze the EMI coupling path, the near-field scanning (NFS) technique is adopted to capture and visualize the current flow path in the discharging process. A useful subtraction method is proposed to eliminate the radiated EMI from the high-voltage discharging current and better visualize the conducted EMI current. According to the NFS results after the subtraction process, the conducted EMI current coupling path can be straightforwardly obtained, and the corresponding mitigation approaches are demonstrated to solve the EMI problem effectively.