Sine wave power inverter

[mincing]

Thanks a lot for the reply,Walcura.

However I can manage snubber calci for Flyback and other SMPS.My problem is with inverter H-bridge snubbers.
Please give any info. if you have or find somewhere.

regards

[Mateus]

Thanks a lot for the reply,Walcura.

However I can manage snubber calci for Flyback and other SMPS.My problem is with inverter H-bridge snubbers.
Please give any info. if you have or find somewhere.

regards

Hello Mincing !

It is probably too late for an answer, but i am new here. Anyway if you still have the problem with Snubber, you could try the following paper, which in my concept is very good. In fact it is for IGBT´s protection but it can give you some help. It is supposed that MOSFETs do not require Snubber networks meanwhile they have peak diode recovery dv/dt > 3 V/ns, but i am not completely sure about this statement.

Good Luck.

Snubber considerations for IGBT applications.pdf

http://www.irf.com/technical-info/designtp/tpap-5.pdf

[Mateus]

Hello everybody !

I have been working with an inverter prototype 500 VA 24Vdc / 120 Vac 60 Hz, H-Bridge single-phase, Mosfet Switches IRF8010 VDSS 100V - dV/dt 16 V/ns, 2 Mosfets in parallel per Switch. The system runs controlled by means of a PWM 3.72 kHz generated by a Microchip PIC 16C74. The DC voltage source (A standard rectifier, Diode bridge + Capacitor), is connected to the H-bridge inverter by means of a duplex 12 AWG 0.9 meters length cable. Probably due to this cable inductance, the DC voltage at the inverter bridge has some spikes with short duration and high amplitude. I have tried to reduce these spikes with 2 electrolytic capacitors 330 µF 160V in parallel (C4), located at the H-bridge DC voltage entry, and it seems to reduce the Spikes quantity, but not the spikes amplitude.

Questions:
1) I have not used Snubber Networks for these switches because it is supposed Mosfets do not required them. Am i wrong , are the Mosfets subject to High risk in this case with these spikes ?
2) The noise caused by these spikes also can affect the control system performance. Could you please give me any suggestion to eliminate or at least reduce these spikes ?

Attached you can find the H-Bridge circuit diagram, and the obtained signals for a resistive 100W load connected to the HV side of a Step Up transformer 13.6/120 V.

Thanks for your comments.

[tahmid]

Hi everybody,

I am a new comer in this forum. I have followed all the postings regarding sine wave inverter as I am interested in it. I am trying to make sine wave inverter of 600va. I made boosting section with sg3525 to convert 12v battery voltage to 350v dc with feedback. I used 100 kHz freq. with etd39 core. I also made battery charging section with separate ferrite core etd34 with 132 kHz freq. I want to make 350v dc rail to 230v AC with full bridge configuration and with pic 18f 1320/4550. While making this section, I am facing problem and invite suggestions regarding these.

In full bridge circuit, upper 2 N channel Mosfets require virtual ground and so keeping those 2 on for 10msec is difficult and hence if I keep the lower mosfet on and upper one pwm-ed with 50kHz, is there any problem?

Which driver is useful for driving mosfets in full bridge configuration?

I have made the sine table and will test soon and hence suggestions are invited urgently.
Hope to get suggestions from you all.

With thanks.

[mincing]

Hello Tahmid,
I have been off the forum for quite some time.
Now back in place!

Can you help me with your design of stepping up dc-dc design with SG3525 and the charger design please!

I have done some work but could not actually get through ,as I had problems in the biginningit self.

Thanks ,
Mincing

[mincing]

Hi everybody,

I am a new comer in this forum. I have followed all the postings regarding sine wave inverter as I am interested in it. I am trying to make sine wave inverter of 600va. I made boosting section with sg3525 to convert 12v battery voltage to 350v dc with feedback. I used 100 kHz freq. with etd39 core. I also made battery charging section with separate ferrite core etd34 with 132 kHz freq. I want to make 350v dc rail to 230v AC with full bridge configuration and with pic 18f 1320/4550. While making this section, I am facing problem and invite suggestions regarding these.

In full bridge circuit, upper 2 N channel Mosfets require virtual ground and so keeping those 2 on for 10msec is difficult and hence if I keep the lower mosfet on and upper one pwm-ed with 50kHz, is there any problem?

Which driver is useful for driving mosfets in full bridge configuration?


I have made the sine table and will test soon and hence suggestions are invited urgently.
Hope to get suggestions from you all.

With thanks.

Yes,

You can use IR H-bridge drivers IR2113 or IR2111 .Preferably the 2113.
There are some H-bridge drivers in Freescale,try getting some and use,b'coz one driver serves all four devices.

rgds,