Sine wave power inverter

[sougata]

Hi,

I do not have a complete design in PBP. My initial design based on 18F452 was a commercial flop so I had to develop one on 16F72/73. Since my initial design there has been a number of improvements in the hardware side too. Like for a 12 volts system I implemented a MOSFET driver with internal charge pump that reduces the switching and conduction loss. Because while the battery is discharging the deep discharge cutoff threshold is generally 10.8 volts so the gates are pumped with merely 10 volts which should drive them into enhancement modes but with a PWM at 20KHz the switching losses are high.

But iw2fvo you are right that there should be complete relevant project to get started. I couldn't do it for babalola though... I definitely have in mind to rig up something for the wiki

[Normnet]

While browsing this microcontroller controlled device caught my eye:
I believe this has the potential to be a game changer!

The AD9833 is a low power, programmable waveform generator capable of producing sine, triangular, and square wave outputs.
The output frequency and phase are software programmable, allowing easy tuning. No external components are needed.
The AD9833 is written to via a 3-wire serial interface.
This serial interface operates at clock rates up to 40 MHz and is compatible with DSP and microcontroller standards.
The device operates with a power supply from 2.3 V to 5.5 V.

Norm

[sougata]

Hi,

The application domain for the AD9833 is much wider than the scope of a sinewave inverter. It is majorly used as a function generator. Since we would be producing either 50Hz or 60 Hz it would be an overkill for the application. Making most of the controller and crushing the BOM is also part of the job.

[Normnet]

Hi,

The application domain for the AD9833 is much wider than the scope of a sinewave inverter. It is majorly used as a function generator. Since we would be producing either 50Hz or 60 Hz it would be an overkill for the application. Making most of the controller and crushing the BOM is also part of the job.

Would it not produce a 50Hz or 60Hz sine wave with little code?
Low volume production may benefit.

Norm

[sougata]

Hi Norm,

Producing the sinewave is not the issue. It is just a counter >> Lookup table >> HPWM not much code indeed. However for a Power Bridge to be driven a lot more needs to be done. So if an AD9833 is used it attracts additional glue logic and circuitry making the design more complex in terms of Hardware. Being the author of FL (did I ever thanked you for it...my bad...I wonder how you could do such an elaborate software FREE....) you already know it is a lot more easy to copy/paste software than hardware!! Moreover the AD9833 is available only in MSOP if I am not wrong which makes it difficult for hobbyist to work upon. Consider the price against a PIC16F1824 on digikey. The AD sells for about $10 and the PIC is $1.5. The AD9833 works on the principal of DDS which is again mimic able by a PIC limited to much lower frequency within the Audio Range.

Since I do not have a complete (in all respect) PBP project on the sine wave inverter, I am making arrangements to do one. I suppose I would start making two PCBs. One with the MOSFET Power Stage (which you can blow up and still hope the micro is not fried !!) the other the controller itself, so that an experimentation platform is available for different options. All in single side, for Homebrew PCB. What do you say ??

[iw2fvo]

Hi Sougata ,
thanks a lot for having reply to me.

I do understand that there is no PCB for the project at the moment , but I am still interested in understanding the system operation and I would like to experiment it on my little laboratrory. I am an Italian Radio Ham and the inverter will be used as a backup power source for my radios only.
Is it possible to have a system description, a block diagram and a schematics diagram for me to implement and test the project ?
Is the program written in assembler ?
I will appreciate very much to read back from you.
Thanks in advance.
Regards,
Ambrogio
Iw2fvo[


QUOTE=sougata;108771]Hi,

I do not have a complete design in PBP. My initial design based on 18F452 was a commercial flop so I had to develop one on 16F72/73. Since my initial design there has been a number of improvements in the hardware side too. Like for a 12 volts system I implemented a MOSFET driver with internal charge pump that reduces the switching and conduction loss. Because while the battery is discharging the deep discharge cutoff threshold is generally 10.8 volts so the gates are pumped with merely 10 volts which should drive them into enhancement modes but with a PWM at 20KHz the switching losses are high.

But iw2fvo you are right that there should be complete relevant project to get started. I couldn't do it for babalola though... I definitely have in mind to rig up something for the wiki[/QUOTE]

[sougata]

Hi iw2fvo,

Since I do commercial designs they are generally a client's property which I cannot publicly distribute. So to produce a Sinewave Inverter the hardware itself could be a great obstacle. PCB being one important component. So I am planning a make a fresh simple hardware design that can be easily produced by an average hobbyist.

BTW to run the radios you would need 13.5 Volts DC (my ham license never got renewed) if I am not wrongs so what are the loads you plan to use with your inverter.

[iw2fvo]

Thanks for the clarification
I did not realized that you are a commercial designer.
Anyway, I am very interested in homebrew power inverter : I will appreciate if you could help in the next future !
I do have very old radio that is operated at 230 Vac 50 Hz.
I am also considering to buy new radio at 13 Vdc ... but they are very expensive to me at this moment; I would like to implement an MPPT solar panel battery charger in case I will buy new radio for Christmas !!! Could you help me in this case ?

Thanks
Ambrogio

[sougata]

Hi,

I am gearing up for the sinewave wiki however at this moment I cannot release any MPPT code.

[sougata]

Update:

Some progress has been made on the modular MOS-BRIDGE PCB. Uses 2x4= 8 MOSFETs mounted on general heatsink driven by 2xIR2110. Employs RdsON based over current detection to switch off MOSFETs even without software intervention. Targeted to be a protected generalized high current Bridge(3.3V ->5V logic level input). Tinkering goes on in the next weekend. May employ cross conduction logic, dead time on the same->Yet to be decided based on available time makes the hardware more rugged and suitable for experimenter's without much experience in PowerElectronics.

[iw2fvo]

Hi Suogata ,
I really hope to see something on this forum just for me to start my homebrewing !
Thanks
Ambrogio