How to isolate and suppress interference in the power supply of a frequency converter drive?

Providing isolated and interference-resistant power to the inverter drive circuit is the cornerstone of ensuring reliable IGBT drive. The drive power supply must electrically isolate the control side from the high-noise power side and resist the high dv/dt noise of the power side. Implementation solutions include: using isolated DC-DC modules with high isolation withstand voltage and low isolation capacitance on both the primary and secondary sides. Adding filter circuits to both the primary and secondary sides of the isolation module: using common-mode inductors (such as the CMZ1608 series) and capacitor filtering on the primary side; and using LC filtering (such as PBZ beads and MLCC capacitors) on the secondary side to filter out ripple and noise. Providing independent isolated power supplies or windings for each IGBT drive channel to avoid power coupling between channels.

Employing magnetically isolated or capacitively isolated integrated drive chips, which integrate isolated power supplies and drive circuitry internally, resulting in better EMC performance. In PCB layout, the isolated power supply module should be close to the drive chip, and the filter capacitors should be close to the pins. The drive power supply ground should be independent, connected at a single point on the drive side, and connected to the power ground via a bead or capacitor. The noise immunity of the power supply is verified by testing the ripple and noise of the output, as well as its stability under applied interference. Etymotic offers a variety of isolated power supply solutions and matching filtering devices.