How to choose between single-point and multi-point grounding for frequency converters

The choice between single-point grounding and multi-point grounding for a frequency converter system depends on the frequency and noise type. Single-point grounding is suitable for low-frequency circuits, where all circuit ground wires converge at a single point before being connected to the earth, avoiding ground loops and common impedance coupling. It is commonly used for analog control circuits and sensor circuits. Multi-point grounding is suitable for high-frequency circuits (typically >10MHz), connecting the circuit to the grounding plane (such as the chassis) via the shortest path to reduce high-frequency grounding impedance. It is suitable for digital circuits and power device heat sinks. Frequency converters typically employ a hybrid grounding strategy: the low-frequency analog section inside the control board uses single-point grounding; the digital and power sections (IGBT heat sinks, filter housings) use multi-point grounding connected to the metal base plate or chassis. The grounding terminals of all equipment (frequency converters, filters, contactors) within the cabinet should be connected to a common grounding busbar or grounding copper busbar, which is then connected to the building ground at a single point. A trade-off must be struck when choosing: single-point grounding may introduce high-frequency impedance problems with long ground wires; multi-point grounding may create ground loops. The effectiveness of a grounding method can be evaluated by measuring the ground noise voltage and spectrum between key points. Eintech's grounding-related components, such as grounding bars and connectors, contribute to achieving a reliable grounding system.