Sine wave inverter without code but using PWM IC TL494 MOSFET Drive Part 3 скачать в хорошем качестве

Sine wave inverter without code but using PWM IC TL494 MOSFET Drive Part 3

(0:00) In this part 3 of MOSFET drive, it's about a full H-bridge modified square wave inverter (can be made to sine wave using proper filter) (0:09) with 4 N MOSFETs plus the driver IC 210 IR 2104 and PWM IC TL 494. This is TL 494, (0:22) these are the driver ICs IR 2104, these two are 2104 and these are 4 MOSFETs in bridge, (0:29) this is one half of the bridge, this is another half of the bridge, this is a half bridge driver, (0:35) this is a half bridge driver and that is how we make a full bridge by putting a transformer here (0:42) and connecting it between these points to the transformer, we get the full bridge output (0:47) and these are output is like this. We will first discuss the circuit (0:52) in detail, then we will go over its understanding. Here, we have the MOSFETs (1:00) as in the bridge configuration, we have discussed it before, part 2 about the bootstrap capacitor (1:06) and the diode to develop an isolated voltage for the gate for the upper MOSFET. (1:13) So, this is an upper MOSFET, this is also an upper MOSFET, and these are the ground reference MOSFETs. (1:19) So, that we have discussed, this has one input, this has one input. In order to feel (1:24) complementary input to these two, so we have used the TL 494. TL 494 is a PWM IC and this PWM IC, (1:34) the frequency selected by the R and C, you can vary this R so that you can exactly get that (1:39) frequency. So, by these are the R and C which takes care of the frequency and then we have (1:44) some special arrangement here for changing the delay time or you can call it dead band. (1:52) So, that what happens that this half and this half will not be switched on at any given time (1:59) at a time. When this half is switched on, this half is off, when this half is switched on, (2:04) this half is off. So, that is what we will see how it happens more in detail. (2:08) So, before that, let us understand these parameters of this IC. The beauty of this IC is (2:17) IR 2104 is dead time is to 5, that is a dead time also we will discuss that the dead time (2:24) here also built-in in this IC. So, what happens for that the cross conduction prevention logic, (2:30) there is no cross conduction, we will understand what is cross conduction (2:35) and then it has got shutdown as we have discussed and other parameter as you can see it here, (2:41) you can withstand about 600 volt offset voltage, but that is not the operating voltage. (2:46) This is the cross conduction feature which is provided by this IC, half bridge IC, meaning (2:53) at if this is positive, this is negative, if this is negative, this is positive. (3:00) But we had seen in the part 2 that at any given time both of them conduct, (3:05) the supply will be short circuited. So, to avoid that, there is a cross conduction (3:10) prevention by providing some dead time. Similarly, it is also built-in with the (3:15) dead time. Because of that dead time, at a time this both of them will not be switching off, (3:20) that is the biggest advantage and that is also being done by some arrangement here. (3:26) Now, we have connected this yellow, this yellow is the output and this is one input, (3:33) B is one input, blue is one input and the red is another input to the oscilloscope what we are (3:39) seeing. So, the dead band control which I was trying to (4:02) tell you is that if you can see this, you see this, what happens, now if I shift the red, (4:12) see there is a dead band, there is a difference, there is a time difference here, you can find (4:17) there is a time difference. But if I zoom it little more, then perhaps you will see it (4:21) little better. You see there is a time difference between switching on and switching off of the one (4:28) set of the other. So, that is the beauty of this particular advantage of this IC, (4:33) it gives a dead band so that at a time both of them will not be switched off. (4:38) Okay. Now, and the shutdown we have discussed yesterday, now if this is 0, that means this is (4:44) high, high means there is no shutdown, when this becomes low, then only shutdown takes place. (4:49) We are talking about the dead band control, here we can do the dead band control as you can see, (4:55) when I change it, you see how this timing is changing. So, let me bring it to the front and (5:08) then you can see how the output is doubled up, we discussed in the last part. And here, (5:15) when you change the dead band here as you can see, you see there is a, if I shift it, (5:22) see that the dead band is increased now. Now, if I bring it down, the dead band will reduce (5:30) or it will increase. Now, see it is now almost coming in the same.