Sine wave power inverter

[sougata]

Hi,

To help you with the software flow the schematic is needed. Wondering how you rigged up a schematic without having fully understood the programming philosophy and the 16F72 !!!!!!!!!!!

[babalola]

Hi Das,

The e(k+1) is the present error
e(k) > past error
u(k+1)> present output of the pi controller
u(k) > past output of the controller
the above are digital parameters of the pi controller and in the course of getting these parameter there is alway need for sampling time (T), the propotional gain of the controller Kp and the zero placement of the controller which is WI
INTERGRAL GAIN KI=Kp*WI
therefore A=Kp(WI*T -1)
while B=Kp

Example if kp=0.04 and WI =3140rad/sec SAMPLING TIME OF 10us

KI=188.4
A=0.04(3140*10US-1)
B=0.04

Remember in PI controller proportional looks at present error while intergral looks at past errors

Regards,
babalola.

[picgak]

Hi sougatha and Thank you,
I have been a regular visitor to the Thread sine wave power inverter for a long
time. I am happy to get a reply for my first query from one of the experienced hands. My
knowledge of PIC programming is minimal. I got the inspiration to do this project for my
home from here. Can you kindly suggest me a link to learn PICBASIC commands in some detail.

[sougata]

Hi,
With the above diagram. The Bridge Rectifier part from the AC mains turns it into an online UPS and needs to be controlled type for steady DC Bus Voltage. As already mentioned if the DC bus voltage is kept steady the output would also be steady.
Regarding PICbasic Pro, I learnt everything from this forum and owe all the contributors a lot. Best is take up one programming challenge at a time and get a grip on the concepts involved. This forum is a life-saver. I do not do basic much still while searching information this is the first place I take a peek.
Good Luck.

[iw2fvo]

Hi Sougata,
It is long time i am looking in this forum for a complete project relevant to a 200 > 500 Watt sine wave inverter.
Is there any possibility for me to have schematics diagram and software for such a project ?
I will appreciate very much your reply on the matter .
Thanks
Ambrogio

[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

[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]

[babalola]

Hi Das,

The e(k+1) is the present error
e(k) > past error
u(k+1)> present output of the pi controller
u(k) > past output of the controller
the above are digital parameters of the pi controller and in the course of getting these parameter there is alway need for sampling time (T), the propotional gain of the controller Kp and the zero placement of the controller which is WI
INTERGRAL GAIN KI=Kp*WI
therefore A=Kp(WI*T -1)
while B=Kp

Example if kp=0.04 and WI =3140rad/sec SAMPLING TIME OF 10us

KI=188.4
A=0.04(3140*10US-1)
B=0.04

Remember in PI controller proportional looks at present error while intergral looks at past errors

Regards,
babalola.

[samrulezzz]

hi Sougata


Actly my guide provided me with the circuits....

Ive attached few interfacing circuits....
hope this is wot u requested....

[sougata]

Dear Sam,

These are the interfacing circuit to do the following in order of your doc.

1. Mains Sense Circuit: Comes from a small step down transformer. The rectified DC voltage is an average representation of the Mains Input Voltage. AN0 is used to sample this pin and decide the status of the mains input. That is within range or outside range. If out of range switches to inverter mode. While in inverter mode used to sense mains restore condition. So this is part of a periodic ADC routine.

2. Battery Sensing Circuit: Used to sense the battery voltage for deep discharge cut-off and charging state change (Boost/Trickle/Equalize). So this is also used in both the inverter/mains-standby mode. Used AN1

3. Charger Circuit: An inverting amplifier. Note that the same shunt (generally in the low side negative battery terminal) is used to measure battery charge and discharge current. The ADC onbaord 16F72 is 8 bit. If a signed AD was performed by offsetting the signal then you loose one more bit and have 7 bit AD for the current sense. So to channels are used with two amplifiers. This is negative battery dischargei.e., current is being put into the battery, thus the inverting amplifier. Phew......

This goes to AN4 and is used only when charging the battery.

4. Load Sensing Circuit : Same as above but for discharge. So a non-inverting amplifier. connected to AN2. Used for overload protection.

5. Output Voltage Sensing: This either comes from a sense winding on the inverter transformer or a small step down transformer (better) connected to the filtered output of the inverter output. This is the voltage feedback for correcting voltage under different load/battery condition. Average DC represents the average output voltage. No in cycle distortion correction possible. (Not within the scope of 16F @ 20MHz, Needs a 18F @ 40MHz)

6. Power Supply Circuit : Your PIC runs on 5 Volts.

7. Sync Pulse Circuit: PORTB.0 INT based zero cross over sensing. Can measure line frequency. Can detect abrupt mains failure (UPS mode). Can do phase angle control on charge circuit. Can detect mains restore. Important for grid connected inverter, where you need to sync your timebase to the mains.


Assuming the above circuits have been ripped from common inverter design prevalent in India. I don't know why people are still stuck with the 16F72 when there are newer introduction like PIC18F1330. I could upgrade my design. Who would buy it ??

This design is far from complete. You need to design the driver stages. Then decide on the software. In India most designs run on software PWM using the compare module. I don't know why ? But they are commercially successful. .... Well I am not.


P.S. - Sorry Sam, I cannot make the code public. (People will come to know about my bad programming skill). I only dream of making an open source sinewave inverter, in PBP. Can't find time. Cause I need to come up with a fresh new design to avoid any legal obligations on my old design.

[samrulezzz]

HI Sougata

Thanking u for takin time of your busy shchedule to explain each of the circuits........

i ve also got the mosfet drive circuits designs......but could not attach as i dont have a soft copy of the designs.....

the design is all but complete for the software code....which i was wanting help on....
actly was hopin u wud help me out on the code.....


but I fully understand ur situation regarding leagal issues......so if u cud help me in some other way like

if u knw any1 among ur frenz who can help me write the code.....

or u have any bits n pieces of codes u found on net or something dat mite help me


plz let me knw if u can direct me to some other person who can help me with the code.....i don mind paying him his fees for the help in the code....

hopin u can help me out in some way

sam
[email protected]

[sougata]

plz let me knw if u can direct me to some other person who can help me with the code.....i don mind paying him his fees for the help in the code....

hopin u can help me out in some way

sam
[email protected]

If you surf on the net or follow EFY magazine you will find that there are people who are distributing .HEX files for as less as Rs.20,000.00 (USD$ 400) but you will get zero support as far as an academic project report is concerned. I have no idea whether anybody will give you source code. Most of them don't have it. So asking for paid support may be well exceed the scope of your project.

I personally feel that you should start writing your own code and the forum would help. A student project need not be perfect, but should be a proof of concept. So better start with the sine generation. Open loop-no feedback and then achieve other milestones as per time frame of the project.

Where are you located by the way.

[samrulezzz]

hi sougata

ya wot u tell is true....no1 gives the source code normally....

i ve got bits n pieces of codes wen i surfed....
now trying to write a code on my own....
hoping it turns out gud



me located in mangalore karnataka state