GE IS200GDDDG1A

IS200GDDDG1A is a Gate Driver and Dynamic Discharge Board manufactured and designed by General Electric. The interface isolation between the IGBTs and the main processor firing circuits is provided by the Gate Driver and Dynamic Discharge board (GDDD). The GDDD board, as well as the gating circuits for the A and B leg active IGBTs, use dynamic discharge circuit control. This board also provides the regulator's instrumentation. The GDDD board processes the output dc voltage, dc link voltage, shunt current mV input, and heat sink thermistor input before sending them to the LDCC processors for use by the regulators.

Jumpers

JP1 - JP3 jumpers on the GDDD board configure the following items:

The JP1 jumper configures the dc output voltage input level to the GDDD board inputs APL-6 and BPL-5. It must match the value in EE.612 (VDCMAX).
The JP2 jumper configures the dc link voltage input level to the GDDD board inputs CPL-12 and CPL-2. It must be consistent with the value in EE. 612 (VDCMAX) (VDCMAX).
The JP3 jumper configures the dc dynamic discharge reference to the GDDD board's inputs CPL-12 and CPLCOM. It should correspond to the level in EE.612(VDCMAX), so that when EE.612 = 604, JP.3 = 500, and when EE.612 = 360, JP.3 = 300.

IS200GDDDG1A LEDs

The LED "Bridge OK," DS100 on the GDDD board indicates that no IGBT leg faults or overcurrents have been detected.
The LED "IMOK", DS101 on the GDDD board indicates that there are no bridge faults, the unit is not reset, the power supply voltages are correct, and no dynamic discharge faults have been detected.
The LED DS102 "DD AUX POWER AVAILABLE" indicates that auxiliary power for the dynamic discharge circuit is available from the dc link source via the RDS connection.

Test Points

Analog TP1 0-5 V proportional to PWM output voltage of a bridge
TP2 Analog 0-5 V proportional to the output current of the PWM bridge
TP3 Analog 0-5 V proportional to the dc link voltage of the PWM.
TP4 DCOM GDDD board signal common reference
Dynamic Discharge command value TP5
Dynamic Discharge feedback value TP6
TP7 When combined with TP8, this test point provides the PWM bridge's dc output voltage.
TP8 When combined with TP7, this test point provides the PWM bridge's dc output voltage.

Procedure for IS200GDDDG1A board replacement

Remove all input power.
To reveal the PSCD board, open the upper board rack door. Behind this board is the GDDD board.
Remove the latch and lower the board rack.
Disconnect all cables from the GDDD board with care, as shown below:
Carefully pull the tab on ribbon connectors with pull tabs.
One edge of the connector is secured to the board plug for plug connectors. Remove the securing clip and gently pull on the connector's sides until it comes free.
To remove the connector from a stab connector, use needle-nose pliers.
Remove the GDDD board from the rack by releasing the securing clips that hold it in place.
Set the jumpers on the new board to match the jumpers on the old board.
Install the new board and reconnect all cables, making sure that each connector is seated properly on both ends.

Features

The dynamic discharge circuitry on the GDDD board regulates the C leg of the 3-phase IGBT pack. In the case that control power is lost, a backup power source is supplied to the GDDD board using the RDS resistor for the discharge circuit.
The control level of the dc link by the dynamic discharge circuit is set by jumper settings on the
GDDD board.
The dc link capacitors are connected to the IGBT bridge via the IAXS board, along with dynamic discharge control and gate control from the GDDD board. The IAXS board serves as a connection point for the control circuitry's sensing feedback and dc output voltage.