3000W Inverter Circuit Diagram: 24V to 230V AC, Pure Sine Wave, SG3525, STM32, SiC/IGBT

User question

inverter 3000 watt circuit
diagram

Artificial Intelligence Response

Direct answer to the question

• A 3 kW inverter is not one “single-page” circuit; it is a system made of several tightly-coupled power-electronic stages.
• Below is an engineering-grade block diagram, a representative partial schematic and the critical component list you would need to realise a 3000 W, 24 V DC → 230 V AC, pure-sine-wave inverter.
• Because of the lethal voltages/currents involved (≥125 A on the low-voltage side, ≈325 V DC and 230 V RMS on the high-voltage side) the design must include solid thermal, short-circuit, over/under-voltage and isolation provisions.

Detailed problem analysis

1. Power budget & topology choice
   • P = 3000 W, η (target efficiency) ≈ 91 % → Pin ≈ 3300 W
   • With 24 V battery ⇒ Iin ≈ 3300 W / 24 V ≈ 138 A (still manageable with 25 mm² copper)
   • Two mainstream architectures
   a) Low-frequency transformer inverter (direct 50/60 Hz drive) – simpler magnetics, heavier copper/iron, lower efficiency (≈85 %).
   b) Two-stage high-frequency (recommended):
   – Stage-1: 24 V DC → 380 V DC via full-bridge, 35 kHz transformer + rectifier.
   – Stage-2: 380 V DC → 230 V AC via SPWM full-bridge + LC filter.

2. Functional block diagram (HF two-stage)

   [24 V Battery]
   ↓ (fuse 150 A, TVS, EMI filter)
   [Bulk input capacitors 6 × 4700 µF 35 V]
   ↓
   ┌───────────────── Stage-1: DC-DC Boost (≈35 kHz) ─────────────────┐
   │ SG3525 @35 kHz → Gate driver ICs (2 × IRS2186) │
   │ ► Full-bridge 4 × 100 V MOSFETs (e.g. IPP110N10N3) │
   │ ► HF transformer ETD59, Np:Ns ≈ 2.2:25 (for 24 → 380 V) │
   │ ► Secondary full-bridge rectifier (4 × STTH6006) │
   └───────────────── 380 V DC BUS (470 µF 450 V + snubbers) ─────────┘
   ↓ (NTC inrush, bus shunt 5 mΩ, Hall current sensor)
   ┌───────────────── Stage-2: DC-AC Inverter (SPWM) ─────────────────┐
   │ MCU (STM32 / C2000) generates 20 kHz carrier + 50 Hz sine │
   │ ► Gate driver 2 × IR2110 (with 250 ns dead-time) │
   │ ► 600 V IGBTs 4 × FGA60N65SMD (or 650 V SiC FETs) │
   └──────────────────────────────────────────────────────────────────┘
   ↓
   [LC output filter: L = 2.0 mH, C = 1.0 µF / 305 VAC X2]
   ↓
   [230 V AC, 50 Hz OUTPUT] → RCD / GFCI, AC fuse, MOV surge arrestor

3. Key calculations (core items)
   • Transformer apparent power: S ≈ P/η ≈ 3.3 kVA → choose 3.5 kVA core.
   • HF transformer flux: \( Ae = \frac{V{pri}}{4 f N B_{max}} \) → at 35 kHz, Bmax ≤ 0.25 T, ETD59 meets thermal margin.
   • Output LC corner: \( f_c = \frac{1}{2\pi\sqrt{LC}} \) choose fc ≈ 1.8 kHz (<20 kHz carrier / >50 Hz fundamental).

4. Control & protection
   – MCU closed-loop RMS regulation via AC RMS/Bus voltage feedback.
   – Fast cycle-by-cycle over-current (hardware comparators) <2 µs.
   – Battery UVLO 21 V, OVLO 30 V; bus OVP 420 V.
   – Thermal cutoff 90 °C on heatsink + 120 °C on transformer.

5. Thermal design
   – Stage-1 MOSFETs: total dissipation ≈ 40 W → 0.9 °C/W heatsink + forced air.
   – IGBTs: ≈ 55 W combined → isolated pad, 0.6 °C/W sink + fan.
   – 80 mm × 2 blower giving 100 CFM across both sinks and DC bus capacitors.

6. Partial schematic (power stage only – simplified)

 === Stage-2 H-Bridge (380 V BUS) ===
380 V BUS (+) ────o───────────────o─────── AC_L
| | (to filter)
QH1 ─────┘ QH2 ──┘
IGBT | |
o o
| |
AC_N─────────o────────────── AC_N
| (to filter)
QL1 ─────────────┘ QL2 ───┘
IGBT
BUS (−) ─────────────────────────────────────────

(Each switch leg: 2 × IGBT in parallel for current sharing; gate resistors 15 Ω; 1 µF/400 V snubber across each leg.)

Current information and trends

• Wide-bandgap devices (SiC FETs, GaN HEMTs) now enable 98 % efficient 3 kW inverters with 100 kHz switching and smaller magnetics (TI TIDA-010054, Infineon EVAL_3KWTL_2).
• Digital control (C2000, STM32G4, Microchip dsPIC33) dominates for THD < 2 %.
• Ready-made half-bridge power modules (e.g. Vincotech, Semikron) simplify layout and EMI compliance.
• Regulatory push (UL 1741 SB, IEC 62109-1/-2) requires certified isolation and anti-islanding for grid-tied versions.

Supporting explanations and details

• Why 24 V not 12 V? Halving current (138 A vs 276 A) reduces I²R loss by 75 %.
• Why two-stage? Eliminates 50 Hz iron (25 kg) and improves efficiency/THD.
• Dead-time: ≥400 ns prevents cross-conduction; too large increases distortion.
• Snubbers + RC clamp tame transformer leakage spikes; otherwise MOSFET avalanche destroys devices.

Ethical and legal aspects

• Lethal voltages: enclosure must meet IP2X touch-safe rules.
• EMC: CISPR 11 class A radiated/conducted limits; mandatory shielded enclosure, common-mode chokes.
• Disposal: Large electrolytics are RoHS but require WEEE compliant recycling.

Practical guidelines

1. Prototype at 10 % power with adjustable DC supply (0-30 V / 10 A).
2. Validate gate waveforms with differential probe, <10 ns rise-time.
3. Ramp to full battery voltage, then full load with resistive dummy load (heater).
4. After thermal soak (30 min @3 kW) verify heatsink <85 °C and transformer <100 °C.
5. Only then attach inductive/SMPS loads.

Common pitfalls & cures
• Shoot-through → check gate-driver ground bounce, use Kelvin source.
• Audible whine → increase carrier to 23 kHz, retune LC.
• Bus over-voltage on load dump → add 800 V TVS + active crowbar.

Possible disclaimers or additional notes

• The schematic fragments supplied are illustrative; exact values depend on magnetic design, PCB parasitics and chosen switching frequency.
• Building a 3 kW inverter without high-voltage experience is dangerous; commercial certified units are often cheaper than the BOM of a safe DIY build.

Suggestions for further research

• TI reference designs: TIDA-010054 (3 kW SiC inverter), TIDM-HV-1PH-DCAC.
• Infineon AN 2016-11 “Designing a 3 kW solar micro-inverter with CoolMOS™”.
• IEEE Transactions on Power Electronics, “Comparison of Si, SiC and GaN devices in single-phase 3 kVA inverters”.
• Books: Erickson & Maksimović “Fundamentals of Power Electronics” (HF transformer chapter).

Brief summary

A 3000 W inverter consists of:
1) A high-current low-voltage input stage,
2) A DC-DC boost (or low-frequency transformer) to create a high-voltage DC bus,
3) A full-bridge SPWM stage,
4) An LC filter and comprehensive protection/feedback circuitry.
Modern designs favour a 24 V or 48 V battery, a 35-100 kHz HF transformer, digital SPWM control and SiC/IGBT switches to achieve >90 % efficiency and <3 % THD. Because of the severe electrical and thermal stresses, only experienced engineers equipped with isolation probes, thermal analysis tools and knowledge of relevant safety standards should attempt to build such a device.

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