12V300W unipolar isolation pure sine wave inverter design

Basic parameters of the machine

Nominal power: 300W, continuous power: 250W, peak power: 600W;

Output voltage: The output is single-phase 220VAC (effective value), and the frequency is 50±1Hz.

Overall efficiency: more than 87%; 300 times of startup with short circuit, 200 times of short circuit startup;

Overload protection 500W; short circuit immediate protection; undervoltage alarm 10.3V delay 1.5S;

Undervoltage protection 10V immediately shuts down; overvoltage protection 15V immediately shuts down; overheat protection: 65℃

Basic information of this

Generally speaking, this is a 12V unipolar isolated pure sine wave inverter . This inverter consists of three parts: the front-stage driver board, the rear-stage driver board, and the power board.

1. The front-stage driver board is mainly composed of three parts: power supply part, PWM drive part, and over-voltage and under-voltage protection part;

2. The post-stage driver board is mainly composed of three parts: the SPWM signal generation part (single-chip microcomputer EG8010), the IR2110 driving part, and the over-current protection part.

3. Main components of the power board: The power board mainly includes the front-stage reverse connection protection, DC-DC push-pull boost, rectification and filtering, and H-bridge inverter parts; it also includes small parts such as overcurrent protection circuit, quasi-closed-loop feedback part and undervoltage alarm circuit.

Pre-driver board

Empty board image:

Empty board image:

After installation, it will look like the following figure:

Next, it is time to debug the over-voltage and under-voltage protection on the power board. This part should not be difficult, so I will not go into details here (there should be no problem according to the parameters on the drawing).

Finally, it is the most important overload and short-circuit protection test of the machine, which is also the most important performance of the inverter .

Everything has been basically debugged successfully. Let the machine work at no load for more than 1 hour, then shut it down and discharge the high voltage.

Then install the radiator as shown above.