Service manual

Edition 101222
-- 11 -- s1Cad160
AP1:1. EMI mains filter
The EMI mains filter contains capacitors and inductors intended for suppression of
the common--mode interferences and the differential--mode interferences. The EMI
filter contains following parts: L05, C1, L02, C5, C8, C16. The resistors R30, R31
provides discharge path for the filter’s capacitors.
AP1:2. Pre--charge circuit
The pre--charge circuit contains diodes V01, V02 and PTC resistors B01, B02.
Internal diodes MV3, MV4 of the power module together with diodes V01, V02
creates the non--controlled rectifier. The filter capacitors C2, C21, C22 are charged
by this rectifier via non--linear resistor B01, B02 up to the amplitude value of the
mains voltage. It is lower then the eventual DC bus voltage, nevertheless it protects
the supply mains and capacitors from the big inrush currents and makes easier
start of the PFC boost converter.
After charging of the capacitors, the auxiliary supply placed on the control PCB,
starts to work, providing also firing pulses to thyristors. The main rectifier made of
thyristors MV1, MV2, and diodes MV3, MV4 takes over the rectifying role.
The boost converter created by the inductor L03, switch MV5 (and MV6), diodes
MV7, MV8 (MV9, MV10) starts working, charging the DC bus capacitors to
390...400V.
AP1:3. Two--switch forward converter
The two--switch forward converter is created on transistors MV11, MV18, and
diodes MV14, MV15. Others diodes and transistors if exists, are not activated.
There is the current sense resistor MR1 placed on the (--) placed before the PFC
converter. It’s purpose is to provide information of the momentary current to the
PFC control system what is needed for creation of the average current control loop
in the PFC control.
Drivers for the switches in the PFC and forward converters are placed on the power
PCB.
AP1:4. Current sense transformer
The current sense transformer T02 is placed on the (--) line. It senses the pulse
current, which is needed for creation of the peak current control loop in the
inverter’s control system.
AP1:5. High frequency transformer
The high frequency transformer is mounted on the power PCB. Probability of
replacing the power transformer in service practice is very low. In addition, it may
have a place only along with the change of the base PCB, as desoldering is
virtually impossible. Nevertheless, in a case of replacement one should connect it
to adequate market points of the power PCB.
Warning! Placement of the points 1 and 2 is different on the PCBs with different
semiconductor modules. Follow the marking on the PCB. If they are not readable,
follow the assembly drawings in the present service manual. Note that two different
solutions are possible.
NOTE!
The proper connection of outlets is obligatory.