STEVAL-DCAC1KCB [STMicroelectronics]

The STEVAL-DCAC1KCB is a dual-stage digitally controlled DC-AC power inverter evaluation board.

The modular design approach makes it easier for the user to test and debug the various sections involved.

The system consists of a power inverter board, auxiliary power supply board, and a microcontroller board.

The DC-DC step-up conversion is based on a full bridge LLC resonant topology, while the DC-AC conversion is based on an H-bridge inverter.

The LLC resonant circuit is designed to operate at a fixed resonant frequency without regulating the DC-DC converter output voltage, and the open-loop operation.

The AC output voltage is regulated by varying the modulation index (MI) of the H-bridge stage.

The fixed operating frequency of the LLC converter ensures maximum efficiency irrespective of battery voltage and extends the battery back-up time. The DC-DC stage open loop operation also means lower computational load on the microcontroller.

• 1500 VA digitally controlled power inverter
• Full bridge LLC + full bridge rectification + H-bridge inverter
  • LLC working in open-loop at resonant frequency to have maximum efficiency of DC-DC stage
• Output voltage: 230 V ac ± 10%
• Output THD: <5% for load >20% of maximum capability (resistive load)
• Input voltage range: 42 – 54 V dc
• Efficiency: > 93.2% at 50% of load (peak), > 92.1% at 100% of load
• Built-in comprehensive safety mechanisms
  • Low and high input voltage cutoff
  • Low and high output voltage cutoff
  • Output over current/over load protection
  • No-load protection
  • Input reverse polarity protection