Inverter is divided into four parts, each part to do a piece of PCB board. Respectively is the “power board”, “SPWM driver board”, “DC-DC driver board”, “protection board”.
1 power main board:
The power board includes DC-DC push-pull and H bridge inverter two parts.
The machine’s BT voltage of 12V, full power, the working current can reach 55A above, DC-DC boost part of a pair of 190N08, the 247 package of cattle, as long as the heat to do in place, a pair of you can output 600W, you can also use IRFP2907Z, the output power is almost the same price. Main transformer with the EE55 of the magnetic core, in fact, on the 600W, with EE42 is enough, I am in order to facilitate the system, plus the EE55 is there, it used the EE55. on the main transformer winding, the following details. Push-pull part is powered by a symmetrical balance way, this has two advantages, one is can guarantee high current when the second power tube work state of symmetry and ensure a unilateral fever phenomenon can not occur; the second is can reduce the PCB reverse current density of the tin layer stack, of course, can also be greatly reduced because of the interference caused by the unbalanced current. High voltage rectifier fast diode, using the TO220 package RHRP8120, the tube reliability is very good, I used a second-hand tube, only 1 yuan a. High voltage filter capacitor is 470uf/450V, in the case of possible, as much as possible with the capacity of some, to improve the high pressure part of the load characteristics and reduce interference are good.
2 SPWM driver board
As with my 1KW machine, the core part of SPWM uses the TDS2285 chip of Zhang Gong. The chip on the details, you can see my previous post: http://bbs.dianyuan.com/topic/563779 here unspecified said. U3, U4 composition sequence and dead time circuit, final output used four 250 optocoupler, H bridge of the two works, bootstrap power supply, do is simplified circuit, can not be isolated power supply.
Because BT voltage will vary between the 10-15V, in order to have a reliable driving H-bridge, optocoupler 250 totem pole output stage voltage must to between 12-15, not less than 12V, otherwise it may enable H bridge power tube failures trigger. So, here with a MC34063 (U9), the BT voltage up to 15V (the booster circuit provided by the clock), the experiment proved that this way is very effective.
3.DC-DC driver board
DC-DC boost driver board, the use of a very common line, with a PWM to achieve the output of SG3525, after the two groups of totem output, the experiment, if the use of a pair of 190N08, the totem part can be omitted, directly with the 3525 driver is enough. Because the DC-DC driver board, and my 1000W interface is generic, so there are two groups of output, the machine on the use of a set of. The board has two small button switches, S1, S2, S1 is the boot, S2 is off, you can control the start and shutdown of the inverter.
The driving plate is connected with the J3, the J4 interface and the power plate, wherein, the J3 of the 1P is limited to the input end of the pressure feedback.
4 protection board
I did not do this protection board, there are the following reasons: first, the machine can not protect the machine can work, and this period of time is relatively busy, so the protection board is pulled down; followed by: I announced the power of the motherboard, is amended, the interface also made changes to the protection board, and I use the prototype is not modified PCB board, even made a protective plate, also do not go up. I would like to have a friend if I use my PCB documents to manufacturers proofing, do not forget to give me a set of, sent to me, I can be based on the new power of the main board to draw the protective plate.