How to separate the power ground and signal ground of the frequency converter

In inverter PCB design, properly separating power ground and signal ground is crucial to preventing high-noise current from contaminating sensitive control circuits. Power ground carries large currents from rectification and inversion, containing abundant switching noise and high-order harmonics; signal ground serves as the reference ground for control boards, sampling, and communication circuits, requiring cleanliness. Separation methods: The power and signal sections are physically separated in the layout. On the PCB, the ground planes of the two sections are physically separated using copper-free areas or trenches. After separation, they need to be connected through specific points to establish a common DC reference potential and discharge static electricity.

Common single-point connection methods include: connecting via ferrite beads (which have high impedance to high-frequency noise but low DC resistance); connecting via 0-ohm resistors (facilitating testing and adjustment); and connecting via one or more safety Y capacitors (providing a path for high-frequency noise to the chassis ground while maintaining DC isolation). Connection points should be selected in areas with minimal interference, typically near the grounding terminal of the power input. Signal lines must never cross the gap between the separated ground planes; otherwise, their return path will be cut off, leading to serious EMI problems. E-Tech Electronics' ferrite beads and safety Y capacitors are commonly used devices for achieving safe and effective grounding separation.