How to design a hybrid grounding system for frequency converters

Designing a hybrid grounding system for a frequency converter requires combining the advantages of single-point and multi-point grounding to adapt to the grounding requirements of different frequencies. A hybrid grounding system typically divides areas: low-frequency sensitive areas, such as analog control boards and sensor circuits, use a single-point grounding tree structure, with all ground wires converging at a single point and connected to the system reference ground to avoid common impedance coupling. High-frequency noise areas, such as power boards, IGBT heatsinks, and switching power supplies, use multi-point grounding, connecting to the metal base plate or chassis via the shortest path to reduce high-frequency grounding impedance. The chassis itself, as the common reference plane for all high-frequency groundings, must be robust, continuous, and have low impedance.

Ground connections between different areas employ specific strategies: the trunk of the analog single-point grounding tree is connected to the chassis via a ferrite bead or a 0-ohm resistor; power ground is directly connected to the chassis at multiple points; digital logic ground may be connected to the chassis or power ground via a small ferrite bead. Cable shielding is typically connected to the chassis of the respective equipment at both ends. During the design phase, the noise distribution on the ground plane must be verified through simulation or measurement to prevent noise propagation through the ground plane. A well-designed hybrid grounding system, capable of balancing low-frequency accuracy and high-frequency noise control, is crucial for EMC success in complex inverter systems. Audiotech offers a variety of grounding isolation and connection devices, ideal for implementing hybrid grounding designs.