IDC-AC Inverter Overview
A DC-AC power supply is also called an inverter. Common DC-AC supplies within 3kW include car inverters, outdoor energy-storage stations, small UPS units, small home ESS and solar PV inverters; their input is usually DC12V~DC48V and output AC100~120V or AC220~240V. The recommended solution here is EG Micro's EG8015 — simple circuit, excellent value. The EG8015 integrates a digital SPWM sine-wave generator and high/low-side MOSFET drivers with 600V, 2A drive capability; it has a built-in ±1% accuracy 24MHz high-speed clock oscillator, or an external high-precision 24MHz crystal can be configured via UART; the external circuit is very simple.
Scheme selection reference by power range
| Input Voltage & Power Range | Topology | Recommended Chip Solution | Application |
|---|---|---|---|
| Input within 30V, small-medium power | Front stage: push-pull; rear stage: SPWM conversion | Front: EG1611; rear: EG8015 | Car inverters, outdoor power |
| Input above 30V, medium-large power | Front stage: full-bridge or 4-switch Buck-Boost; rear: SPWM conversion | Front: EG1611 or EG1151; rear: EG8015 | High-power PV, energy storage systems |
IIDC-AC Inverter Design for Small-Medium Power up to 2000W
A complete inverter consists of two stages: a front-end boost and a rear-end DC-AC inversion. For the front-end boost refer to the relevant chapters of the Isolated DC-DC Circuit Design document. Only the EG8015-controlled SPWM AC output circuit of the inverter stage is given here.
Key circuit specifications
Input voltage: DC300V
- Output voltage
- AC220V
- Output power
- max 2kW
- Output waveform frequency
- fixed sine 50Hz/60Hz, or 0-400Hz adjustable (pin configuration)
- Modulation
- unipolar/bipolar SPWM
- Inverter switch
- SGT15T60QD
- Inverter transformer
- EQ4020 (1kW)
- Inverter inductor
- Sendust T30-15, 1mH, 2A
- Overall efficiency
- >95%
- Dead time
- 300ns/500ns/1.0µs/1.5µs (4 selectable levels)
- Protection
- overvoltage, undervoltage, overcurrent, over-temperature, short circuit
- Communication
- RS232 serial (voltage/frequency parameters configurable)
- Display
- supports 128×32 LCD for real-time parameters
- Soft start
- 1s response time to prevent inrush
Circuit diagram:
