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PICAXE based inverter

I've been having this idea for awhile. Create a dc to ac inverter using 2 8M PICAXEs as the timer Controling an H-bridge hooked up to a 12VDC battery. Then have the first PICAXE control an H-bridge to convert 12VDC to 12VAC. The MOSFET H-bridge would be sent to a full-wave voltage multiplier circuit, using diodes and capacitors, converting it into around 192VDC. Then this would be the power given to the second MOSFET H-bridge and another set of 4 I/O pins from the second 8M PICAXE would control the H-bridge into converting it into 192 VAC@60Hz.

I have an idea of creating a microcontroller based inverter using the 08PICAXE. The 08PICAXE is simply just the timer to create "synthetic" AC current. The PICAXE controls two MOSFET H-bridges. Each H-bridge has 5 N-channel parralled, another 5 N-channel parralled, 5 P-channel parralled, and another 5 P-channel parralled. The idea is to eliminate the use of a transformer and have maximum wattage with a reasonable price. The first H-bridge is connected to P0, P1, P3, P4 and a 12VDC power source. The PICAXE timer creates a 12VAC@58hz. This is then sent to a diode and capacitor multiplier(10x) circuit. The voltage is now 120VDC. This is sent to the second h-bridge to be converted into 120VAC@58Hz. The second H-bridge is connected to  P0, P1, P3, P4 and the voltage multiplier circuit.

half wave   

Full and Half wave camparison

















What do you guys think. I will look forward to your criticism and word of wisdom ;D.


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Forget the second PICAXE, use a transformer with the correct winding ratio (~1:16) to convert 12V to 192V directly. You won't need a full H-bridge to drive it, a half bridge will suffice. Have a look at some ZVS driver circuits for ideas.

What is the AC output going to be used for? Does it need to be close to a true sine wave? What power will the output have to be able to deliver?

I forgot to state this but i was trying to avoid tranformers due to price and limited selection. The ac output is going to be used to power a leafblower for a hovercraft. the MOSFETs are high amperage power transistors.

how will you get nagative volts?

on the voltage multiplier ac is turned into dc. the + and - outputs from the voltage multipleir is connected to the second h-bridge, supplying + and - power to it.

What is the power rating on the leaf blower? Also what will be supplying the original 12V?

Capacitive voltage converters can be very efficient, but to make one that can deliver the power you're probably going to need it'd have to be a big and expensive circuit. I'd be surprised if you could make it smaller or cheaper than if you'd used a transformer.

Also if the PICAXE is just being used as an oscillator, go for one of the many cheap 555 timer ICs instead.

The power Suppply will be a 12V Marine Battery, however I'm not sure of the wattage on the leafblower because it is not mine. This circuit only needs to run for approximatelly 8 min. It is being used for a competition for a hovercraft. I also chose to use a microcontroller because you can programmatically change the Hz. Also in this challenge we are rated on how technical the project is.(and it gave me a reason to start using PICAXES :D) I also couldn't find a cheap transformer with the winding ratio i wanted, so i just decided to go with a capacative voltage converter.