Archives for March, 2014

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Capstone Update – Sine wave Inverter

The first milestone of my final capstone project involves making an inverter from scratch. The inverter also has to output a relatively clean 60Hz sine wave.

The inverter is to be supplied from a solar panel. For my small scale prototype so far I only used a 9V battery + the Arduino 5V supply since it is convenient to work with.

My inverter consists of an H-Bridge which is basically four MOSFETs that switch on in pairs. The circuit I made is very bare bone but gives a decent sine wave.I used an Arduino Uno to do Pulse Width Modulation(PWM) to switch the MOSFETs and then filtered the output.

As seen, the sine wave was relatively decent for this type of set-up. Putting in a better filtering system and some pull-down resistors, etc would yield an even better result. Also creating an actual PCB over a “spaghetti circuit” would help with noise as well.

Also you might notice the oscilloscope I’m using is a portable handheld one. It has a good resolution and is good for my application as I am not working with high switching frequencies (greater than 1Mhz). It’s an ARM Nano DSO201 if you’re wondering and is not expensive.

Below are some snapshots of my prototype:
Inverter circuit

Inverter output