grmahun Posted June 9, 2006 Report Share Posted June 9, 2006 I want to design a three- phase, 380V,50Hz inverter from a battrey of 12 - 24V dc source. This needs six pulse gating signal for the six SCRs or MOSFETs.Could you please help me with the design of these gating signals.TQ in advance. Quote Link to comment Share on other sites More sharing options...
ante Posted June 10, 2006 Report Share Posted June 10, 2006 Hi,What are the expected output ratings? Quote Link to comment Share on other sites More sharing options...
indulis Posted June 13, 2006 Report Share Posted June 13, 2006 I think the more interesting question is how to phase shift each of the gate pulses 120 degrees for each phase!! Quote Link to comment Share on other sites More sharing options...
ante Posted June 13, 2006 Report Share Posted June 13, 2006 Hi,I think you should look at an IGBT inverter bridge for this. Perhaps it is possible with mosfets too but common thyristors should be avoided I believe. This can be controlled by a 12-puls system, much like the second half of a 3-phase motor AC-drive. It will not produce perfect sine wave but close enough. If you need high output power then 12 and 24 Volts system should be avoided, the currents will be troublesome to control. Quote Link to comment Share on other sites More sharing options...
grmahun Posted June 14, 2006 Author Report Share Posted June 14, 2006 The expected output ratings : 3kw,380v(L-L),50HZ The phase shift 120 degree including dead time generation betweenthe gating signals of mosfets in one leg. There is no need of to get perfect sine wave it can be square wave because this inverter is used to drive 3 phase induction motor. I think IGBT could be better as posted by Ante but we have only accese to mosfet in our lab.The DC could also go up to 48V. Quote Link to comment Share on other sites More sharing options...
ante Posted June 14, 2006 Report Share Posted June 14, 2006 Even at 48 Volts you still have to deal with about 70 – 80 A at 3000 W output! Quote Link to comment Share on other sites More sharing options...
grmahun Posted June 15, 2006 Author Report Share Posted June 15, 2006 Does that mean there is no alternative to drive a 3 phase induction motor from car battery or solar source for at least power output of 1hp. Quote Link to comment Share on other sites More sharing options...
ante Posted June 15, 2006 Report Share Posted June 15, 2006 A regular size car battery will not run a 1hp output motor for more than a few minutes. The battery will be destroyed after only a few cycles (charge/discharge) since a starter battery is not suitable for deep cycle use (deep discharge). Quote Link to comment Share on other sites More sharing options...
grmahun Posted June 16, 2006 Author Report Share Posted June 16, 2006 Thanks Ante,I think the source from the battery makes the design more difficult than I thought.How about if the source is from mains using step down transformer and rectified to 12v DC. Quote Link to comment Share on other sites More sharing options...
ante Posted June 17, 2006 Report Share Posted June 17, 2006 I don’t really see the point here. Why convert mains to 12VDC and back to mains for a motor instead of running the motor directly from mains??? Quote Link to comment Share on other sites More sharing options...
grmahun Posted June 30, 2006 Author Report Share Posted June 30, 2006 Hi, Ante. Sorry to be late.The original project is to feed an ac induction motor using voltage source inverter(VSI).So this first needs dc input from one of the following: battery(solar power),diode bridge rectifier or chopper.Usingthis as an input the inverter gives an output of AC.But this AC is variablein voltage and frequancy magnitude so that the torque and speed of the motor can be controlled. Quote Link to comment Share on other sites More sharing options...
electronicavr Posted October 4, 2006 Report Share Posted October 4, 2006 Hi,What are the expected output ratings?i need a circuit or design that: convert a dc voltag(for example 24 or 60)to three phase voltag whit 60 volt or less or 60 volt ac(single phase) to 60 or 70 volt three phase amp=1 amp or less thank :D Quote Link to comment Share on other sites More sharing options...
ante Posted October 4, 2006 Report Share Posted October 4, 2006 Hi, Ante. Sorry to be late.The original project is to feed an ac induction motor using voltage source inverter(VSI).So this first needs dc input from one of the following: battery(solar power),diode bridge rectifier or chopper.Usingthis as an input the inverter gives an output of AC.But this AC is variablein voltage and frequancy magnitude so that the torque and speed of the motor can be controlled. An induction motor is not easy to regulate. Quote Link to comment Share on other sites More sharing options...
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