Three-Phase 380V General-Purpose VFD Reference Design
An illustrative three-phase 380V general-purpose variable frequency drive (VFD) design for speed control of fans, pumps, conveyors and general machinery: three-phase AC 380V input, driving a 2.2kW-class three-phase induction motor, with V/F and sensorless vector control, IGBT power-module inverter, RS-485 (Modbus RTU) and Ethernet (Modbus TCP) communication, an external keypad RJ45 port, multi-function digital / analog I/O and relay outputs. This page gives the function, selection notes and available VOOHU parts for 34 component positions.
Illustrative PCB ⇄ Schematic
The illustrative layout shows placement and component positions; click any position to see its selection notes, recommended parts and package. The board view is an illustration neatly arranged by functional zone (not the actual layout), with the control board and power board drawn on one board; the communication ports, keypad port, control terminals, motor and power terminals sit on the bottom edge, and the motor is an external node.
The Modbus RTU fieldbus enters at terminal J1 and passes in turn VOOHU GDT G1 (WHGD200V1P0B) for primary discharge to chassis ground, bidirectional ESD D1 (WHALD30E2B) for secondary clamping and 4532 signal-line CMC L1 (WHAC-4532A-601T0), which suppresses common-mode interference coupled from IGBT switching noise onto the bus, before reaching isolated RS-485 transceiver U1, whose MCU side connects to the MCU UART. G1 is a 2-pole tube; if both A and B need to discharge to ground, use the 3-pole common-ground WHGT090V1P0A instead. The isolated-side supply of the transceiver and the termination and bias resistor values are set per your design.
Board bill of materials
Click any row to jump to that position and view its selection notes
| No. | Zone | Position | Ref. | VOOHU category | Recommended part | Availability |
|---|---|---|---|---|---|---|
| 01 | A RS-485 · Ethernet | RS-485 communication terminal | J1 | — | — | Non-VOOHU |
| 02 | A RS-485 · Ethernet | Gas discharge tube (primary) | G1 | GDT | WHGD200V1P0B | VOOHU |
| 03 | A RS-485 · Ethernet | Bus TVS (secondary clamp) | D1 | TVS / ESD | WHALD30E2B | VOOHU |
| 04 | A RS-485 · Ethernet | Bus differential-line CMC | L1 | Signal Line CMC | WHAC-4532A-601T0 | VOOHU |
| 05 | A RS-485 · Ethernet | Isolated RS-485 transceiver | U1 | — | — | Non-VOOHU |
| 06 | A RS-485 · Ethernet | RJ45 port (with LEDs) | J2 | RJ45 Connectors | SYT561188AB1A1DB4 | VOOHU |
| 07 | A RS-485 · Ethernet | 10/100 LAN transformer | T1 | 10/100 LAN Transformers | WHSH16F01D4 | VOOHU |
| 08 | A RS-485 · Ethernet | Ethernet ESD array | D2 | TVS / ESD | WHALD03G4U | VOOHU |
| 09 | A RS-485 · Ethernet | 10/100 PHY (RMII) | U2 | Ethernet PHY | JL1101BR-NI | VOOHU |
| 10 | A RS-485 · Ethernet | PHY 25MHz crystal | Y1 | — | — | Non-VOOHU |
| 11 | B Keypad · Control terminals | External keypad RJ45 port | J3 | RJ45 Connectors | WH56A3188C011101 | VOOHU |
| 12 | B Keypad · Control terminals | Keypad ESD | D3 | TVS / ESD | WHALD30E2B | VOOHU |
| 13 | B Keypad · Control terminals | Keypad RS-485 transceiver | U3 | — | — | Non-VOOHU |
| 14 | B Keypad · Control terminals | Control terminals (DI / AI / AO / relay) | J4 | — | — | Non-VOOHU |
| 15 | B Keypad · Control terminals | Control terminal TVS | D4 | TVS / ESD | WHALD30E2B | VOOHU |
| 16 | B Keypad · Control terminals | DI optocouplers · analog conditioning | U4 U5 | — | — | Non-VOOHU |
| 17 | B Keypad · Control terminals | Relay output | K1 | — | — | Non-VOOHU |
| 18 | C Power stage · Motor | Isolated gate drivers ×3 (half-bridge) | U6 U7 U8 | — | — | Non-VOOHU |
| 19 | C Power stage · Motor | Push-pull transformers ×4 for isolated gate-drive supply | T2 T3 T4 T5 | Push-Pull Transformers | WHST06K02A0 | VOOHU |
| 20 | C Power stage · Motor | Push-pull driver | U9 | — | — | Non-VOOHU |
| 21 | C Power stage · Motor | IGBT power module (3-phase inverter + brake) | Q1 | — | — | Non-VOOHU |
| 22 | C Power stage · Motor | Output current sensing (Hall sensors ×2) | U10 U11 | — | — | Non-VOOHU |
| 23 | C Power stage · Motor | Motor U / V / W · brake resistor terminals | J5 | — | — | Non-VOOHU |
| 24 | D Core | MCU | U12 | — | — | Non-VOOHU |
| 25 | D Core | Parameter storage (Flash / EEPROM) | U13 | — | — | Non-VOOHU |
| 26 | D Core | MCU crystal | Y2 | — | — | Non-VOOHU |
| 27 | D Core | Core supply filter molded inductor ×2 | L4 L5 | Molded Inductors | WHYTA0420 Series | VOOHU |
| 28 | E Input · Power | R / S / T three-phase input terminal | J6 | — | — | Non-VOOHU |
| 29 | E Input · Power | Input varistor · X capacitor | RV1 | — | — | Non-VOOHU |
| 30 | E Input · Power | Three-phase rectifier bridge | D5 | — | — | Non-VOOHU |
| 31 | E Input · Power | Bus capacitors · soft start | RT1 C1 | — | — | Non-VOOHU |
| 32 | E Input · Power | Auxiliary SMPS (flyback) | T6 U14 | — | — | Non-VOOHU |
| 33 | E Input · Power | Synchronous buck ×2 (24V→5V→3.3V) | U15 U16 | — | — | Non-VOOHU |
| 34 | E Input · Power | DC-DC molded inductor ×2 | L2 L3 | Molded Inductors | WHYT0630 Series | VOOHU |
Resources & downloads
Board bill of materials
Reference designators, zones, VOOHU categories, recommended parts and availability for all 34 positions. Opens directly in Excel.
Datasheet collection
Datasheet PDFs for the VOOHU parts recommended on this board.
Design files & footprint library
Schematic, PCB, and VOOHU part footprints and 3D models.
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Includes the BOM, datasheets for the recommended VOOHU parts and position-by-position selection notes. For selection advice tailored to your power rating, communication protocol or isolation requirements, please include it in your requirements. We reply within 24 hours on working days.
