Application of TC787 in thyristor three-phase double bridge active inverter system

Application of TC787 in three-phase double-bridge active inverter system: Figure 12-18 shows the schematic diagram of two pieces of TC787 used in a
three-phase double-bridge frequency conversion system where the main power device is a thyristor .
This system can be used to recover electric energy in the factory power test system of high-power internal combustion engines, generators, electric motors, DC
speed regulators, and AC speed regulators. In this system
, two TC787s are used as phase-shift trigger circuits for the 12 thyristors in the two inverter bridges
. Both TC787s operate with a single power supply, and both
operate in a fully controlled double-pulse mode. In the figure, the transformer TY is a synchronous transformer, which provides two sets of three-phase synchronization signals for two TC787s
, and the output transformer TY: is used to
superimpose the square wave voltage output by the two inverter bridges into a staircase wave and feed it to the power grid. In order to reduce the pollution of high-order harmonics entering
the power grid, it is also used to match the inverter voltage with the main grid voltage.
The DC voltage Vd in the figure can be the output of the DC generator in the experimental system, or it can be the DC voltage after
the three-phase alternating current in the experimental system has been rectified by the thyristor device.