How to locate noise sources in the near field of radiated emissions from a PCS (Polymerized Array of Substrate) energy storage system?

During the PCS R&D or rectification phase, using near-field probes (magnetic field probes and electric field probes) to locate radiated emission (RE) noise sources is an efficient method. The location steps are as follows:

1. Preparation and Setup: With the PCS operating normally, use a spectrum analyzer or the FFT function of an oscilloscope, connect the near-field probes, and start from known out-of-range frequencies.

2. Magnetic Field Probe Scan (Applicable to Current Loops): Use the magnetic field probe to scan close to the PCB and component surfaces, finding the points with the strongest magnetic field strength. These points usually correspond to high di/dt current loops, such as the pin loops of switching transistors, diodes, power inductors, and DC-Link capacitors.

3. Electric Field Probe Scan (Applicable to High Voltage Points): Use the electric field probe to scan for the points with the strongest electric field strength. These points usually correspond to high dv/dt nodes, such as the collector/drain of switching transistors and transformer pins.

4. Comprehensive Judgment: Based on circuit principles, determine whether the scanned strong points are potential radiation sources, such as long wires, unshielded interfaces, cabinet gaps, etc. Verify through temporary measures (such as applying copper foil or using ferrite cores).