Axpert MEX-1500/ MEX-3000 Service manual
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3.2 DC TO DC converter (full bridge)
The full bridge topology is a transformer isolated forward-mode regulator. Unlike the
fly-back transformer, the push-pull transformer does not store any energy and output current is drawn
when power switches are conducting.
A full bridge topology is shown in figure 3.2, power switch (Q11,Q17,Q20,Q24,Q40,Q26,Q25,Q39) and
(Q38,Q21,Q22,Q63,Q13,Q18,Q23,Q35) receive 180 out-of-phases. Refer to figure 3.2, the battery
voltage is transformed through a full bridge DC-DC converter to >330Vdc as DC BUS for inverter. When
the line fails, the DC BUS voltage is caught up to supply the power needed by the inverter immediately.
The output voltage (DC BUS) must be higher than the input voltage (BAT+) .It mentioned by the primary
turns and secondary turns. In this circuit, BAT+ =12VDC with MEX-1500-12, BAT+ =24VDC with
MEX-1500-24/MEX-3000-24, DC BUS voltage above 330Vdc.
Figure 3.2 full bridge topology
