3
ANALYSIS OFTHE BLOCK DIAGRAM
NOTE:Unless indicated otherwise, it should be assumed that
the components are assembled on the primary board or
machine.
:C1,C2,C3,C4,C5,C6,C7,L1(inputfilterboard)
Preventsnoisefromthe machine from beingtransmittedalong
themainpowerlineandviceversa.
Consistingof:RV1,RV2,RV3(inputfilterboard)
Prevents spike noise from the mains, with amplitude greater
than400V,fromenteringthemachine.
Consistingof:D1,D2,D3
Converts the mains alternating voltage into continuous pulsed
voltage.
Consistingof:K1,K2,K3,R1,R2
Prevents the formation of high transitory currents that could
damage the main power switch, the rectifier bridge and the
electrolytic capacitors.When the power source is switched on
relaysK1,K2andK3arede-energised,capacitorsC1,C2,C3,
C4,C1A, C2A, C3A C4A and C39 arethen chargedbyR1 and
R2. When the capacitors are charged the relays will be
energised.
Consistingof:C1,C2,C3,C4,C1A,C2A,C3AC4A,C39
Converts the pulsed voltage from the rectifier bridge into
continuousvoltage.
Consistingof:IGBT1,2,3,4,5,6,7,8,9,10
Converts the continuous voltage from the filter into a high
frequency square wav capable of piloting the power
transformer. Regulates the power according to the required
weldingcurrent/voltage.
Consistingof:TA
TheC.T.isusedtomeasurethecurrentcirculatinginthepower
transformer primary and transmit the information to block 14
(primarycurrentreaderandlimiter).
Consistingof:T1
Adapts the voltage and current to the values required for the
welding procedure. Also forms galvanic separation of the
primary from the secondary (welding circuit from the power
supplyline).
Consistingof:D1,D2,D3,D4,D5(secondaryboard)
D1 and D2 convert the current circulating in the transformer to
asingledirection,preventingsaturationofthecore.
D3,D4andD5recirculatetheinductanceoutputcurrent(block
9) while the IGBT's are not conducting, bypassing the power
transformer(block8).
Consistingof:L1,Hall1andHall2
The inductance levels the output current from the secondary
board diodes making it practically direct. Hall1 sensor reads
the current of the pilot arc, Hall2 sensor reads the current
circulating in the inductance and sends it to block 20 (Hall
sensoramplifiers)whichwillprocesstheinformation.
Consistingof:C4,C5(HFfilterboard)
Prevents noise from the power source from being transmitted
throughtheweldingcablesandviceversa.
Consistingof:T2
The HF transformer boosts the signal from block 40 (hf power
source), raising the voltage impulse in the secondary at the
instantwhenarcstrikeisgenerated.
Italsoisolatestheweldingcircuitfromtheprimarycircuit
Consistingof:U4,Q6,T3,U1,U2,U3
Uses switching methods to transform and stabilise the voltage
obtained from block 5 (filter) and supply 2 voltage values of
27V that enable block 14 (driver) to be powered correctly.The
auxiliary power supply board, on the other hand, generates
four further stabilised voltages (U2, U3, U4, U5) equal to a
+12V, +5V, -12V and 5V which are mainly used to power the
controlboard.
Consisting of: U1 (opto-insulators board), Q7, Q8 and U2
(opto-insulatorsboard),Q9,Q10.
Takes the signal from block 13 (flyback power supply) and,
controlled by block 16 (duty cycle maker), makes the signal
suitableforpilotingblock6(chopper).
Consistingof:D3,R1,R2,R3andR9andR16(controlboard)
Detectsandlimits the signalfrom block7 (currenttransformer)
and sets the maximum allowed primary current.This signal is
alsoscaled downso that it can beprocessed and comparedin
block16(dutycyclemaker).
Consistingof:U1(controlboard)
Processes the information from block 18 (adder) and block 15
(primary current reader and limiter) and produces a square
wave with variable duty cycle limiting the primary current to a
maximumpre-setvalueunderallcircumstances.
Consistingof:U4A,U4B(controlboard)
Collects all the information arriving from block 21 (maximum
currentcontrol)andfromblock19(microcontroller),andsends
ittoblock16(dutycyclemaker).
Block 1
Block 2
Block 3
Block 4
Block 5
Block 6
Block 7
Block 8
Block 9
Block 10
Block 11
Block 12
Block 13
Block 14
Block 15
Block 16
Block 17
EMC Filter
Consistingof
Varistor
Rectifier bridge
Pre-charge
Filter
Chopper
Current transformer
Power transformer
Secondary diodes
Inductance and Hall sensors
Secondary EMC Filter
HFTransformer
Flyback power supply
Driver
Primary current reader and limiter
Duty cycle maker
Adder
SUPERIOR PLASMA 90 HF
