Inverter for fuel cell: Please Help

[nau03139]

Hi Everyone

Im currently looking into designing, building and testing a 3kW inverter for a fuel cell. I understand the different topologies there are such as Z-source and LLCC inverters. However I was wondering if anyone could help me with any sources such as paper or journals people have got which may help me to design such an inverter. Note also that I plan to use a Digital Signal Processor to create pulse width modulation for the inverter. Would be greatful if anyone can give me more information to help design such a thing.

If anyone has any matlab simulink models of an Inverter I would be greatful if you could also send me those.

Thanks

David

 

[Taner]

Hi,
please look at attached documents.
best regards,
Taner

 

[julioreye]

Nau0, here i upload something that to me had been useful on my thesis. bye

 

[julioreye]

if you need more, because i got more, just request it.

 

[nau03139]

Thanks.

Would be greatful if you could get me anything on MATLAB SIMULINK models of an inverter for fuel cells if anyone has such a thing. I need to build one to simulate the inverter working.

Thanks again

David.

 

[nau03139]

Ok guys thank-you for the reports you gave me.

My supervisor for this project has said to me that this is my project and I can build my inverter any way I disire. However he did recommend that I build my inverter similar to those designs that had been done before.

The reports of the inverters from American Universities that you guys have sent me took about 6 or 7 people 3 months to complete. I have one academic year to complete an inverter by myself, so if I had to build, design and test something similar to those report I probably would not get it finished in time. And just for the record folks Im from the University of Strathclyde in Scotland.

So what I have decided to do is to go for a simple H-bridge inverter with LC filter and control the PWM by means of an analogue circuit. A transformer will be used to boost the AC voltage up to 230V to plug into the mains. This way I dont have to use a DC-DC converter. It also means I dont really have to buy any new equipment and can just use the stuff that's already avalible to me.

My inverter design is similar to those that have been built previous to my own, only the big difference is that I have decided to use an analogue circuit using 555 timers to create PWM rather than a DSP. This is a good way to get round having to learn how to program my DSP in code composer, however it does mean that designing an analogue circuit can be difficult, so there is no easy way of creating PWM.

The practical work for my project consists of 3 main parts:

1. Model inverter and simultate in MATLAB SIMULINK
2. Design, build and test analogue circuit to control PWM to inverter
3. Design an suitable transforment to boost output voltage from inverter to 230V

I know it might not be a power electronics problem, but I was wondering if anyone on here has anything on creating pulse width modulation for an inverter, using an analogue circuit. I not only have to design an analogue circuit to create PWM but also incorporate a control circuit which takes the power output from the inverter and feeds back to the PWM input and allow me to control the power output to the inverter. It should allow me to give any output power I disire and keep the voltage at 230V.

Please send me anything you've got on analogue circuits to control PWM.

Thanks again

David

 

[Mr.Cool]

looks like you do not actually have the built the entire thing to meet your requirements. just a low power analog control circuit and a transformer are the real things you must build. the rest is simulation work? easy

the controller can be done in analog. i have done this using op-amps. i had a digital controller issuing D-Q current reference to a DAC and from there some op-amps to do a DQ/ABC transformation then to a PI regulator, then to PWM generator. for op-amp circuit.. go look at the DQ/ABC transformation formula and have your op-amps gain and adder/subtractor circuits mimic the mathematical behaviour. your op-amps do not have to do the 120degrees offset as this is done naturally through your transformation.

i had digital controller form a triangle (i.e. an up/down counter) then to a DAC and a couple of op-amps to make an analog triangle wave (carrier wave for PWM generator).

the benefit of this method was a FAST 3-phase current regulator. it had high bandwidth.

problems to watch out for:
- your triangle wave must ensure that there is ZERO DC offset or drift. you can accept some practical minimum in the circuit..
- tuning PI regulator is a pain
- PWM comparator needs a bit of intelligence behind it for pulse correction and minimum pulse and interlock ability

design your controller to work in PER UNITS and then it will be easily adaptable to any power level.

good luck,
Mr.Cool

 

[nau03139]

Hi guys. Thanks for replaying.

I have encountered some problems from building my analogue circuit. The main problem is that my schematic for creating triangular and sine waves only works for a set frequency of 1000Hz. If I lower the frequency to 750Hz (15x50Hz) or 50Hz the circuit fails to function properly.

The reason why I want 750Hz (15x50Hz) is because the triangular wave output to create pulse width modulation needs to be at least 15 times that of the sine wave. However I have read somewhere that it needs to be AT LEAST 15 times the sine wave, so I can set it at 20 times the sine wave (1000Hz) and still get pulse width modulation.

What I am asking in this forum site is that Im wondering if someone can help me design an analogue circuit that can create a sine wave of 50Hz from a +/- 15V supply line. Note that it does not nessesary have to have a 555 timer in the design as I have done to create a triangular wave of 1000Hz.

I did come up with an easy solution to this problem which was to take a signal generator and set the output to a sine wave at 50 Hz and put this together with the output from the triangular wave into a comparator to get pulse width modulation. My supervisor also suggested that I take the mains supply and put it through a step down transformer to get a sine wave of at least 50Hz. I dont really want to do these for my fourth year project as that might be too easy. I would rather build an analogue circuit that would create a sine wave of 50Hz from a +/- 15V supply line.

If anyone out there can help me built such as circuit, please get back to me as soon as possible.

Thanks,

David.

 

[sandhyaram]

Hi...

I need to simulate z source inverter in PSIM... So i want to design L&c for z source inverter. Please some guidance... please help..

Added after 0 seconds:

Hi...

I need to simulate z source inverter in PSIM... So i want to design L&c for z source inverter. Please some guidance... please help..