 | |
| Illustration 1 | g01280990 |
Inverter Cabinet DGL Board Locations (1) Inverter 1A, DGL Board (2) Inverter 2A, DGL Board (3) Inverter 2B, DGL Board (4) Inverter 2C, DGL Board (5) Inverter 1C, DGL Board (6) Inverter 1B, DGL Board | |
Digital Gate Logic Board (DGL) takes the logic level signals from the APC2 that is located in the Controls Cabinet. The DGL isolates and amplifies the signals and then drives the paralleled Insulated Gate Bipolar Transistors. In addition, the AC current from the half-bridge is sensed, digitized, and transmitted back to the APC2. The heat-sink temperature is also digitized and transmitted serially.
The Programmable Logic Device on the DGL also provides local over-current protection for the Insulated Gate Bipolar Transistors. If the peak current level programmed in the Programmable Logic Device is reached, the Programmable Logic Device will disable the gates to the Insulated Gate Bipolar Transistors to prevent Insulated Gate Bipolar Transistor damage. Additional Insulated Gate Bipolar Transistor protection is included in the Programmable Logic Device that does not allow both the bottom and top Insulated Gate Bipolar Transistors to be turned on at the same time. There is a set dead time of five micro-seconds that is programmed into the Programmable Logic Device.
As a third layer of protection both the top and bottom gates have a built-in Insulated Gate Bipolar Transistor desaturation (DSat) detection circuit. This DSat circuit will activate at about 2000 amps. The DSat circuit will signal a fault and perform controlled shutdown of the Insulated Gate Bipolar Transistors.
The DGL consists of a control section and two gate drive sections.
LED Indicators
The following table shows the Customer Contacts Interface Board LED indicators and the indicators purpose. These LEDs are normally OFF and latch ON and remain latched in the event of any of the above faults. The power supply needs recycled to reset the latched LED.
| Digital Gate Logic Board LED Indicators | |
|---|---|
| LED | Purpose |
| D1 | DSat_top: The Top Insulated Gate Bipolar Transistor had an excessive current due to instantaneous overload or a faulty bottom Insulated Gate Bipolar Transistor. |
| D2 | DSat_Bottom: The bottom Insulated Gate Bipolar Transistor had excessive overcurrent due to instantaneous overload or a faulty top Insulated Gate Bipolar Transistor |
| D3 | Overcurrent Fault: Output current in excess of 1600A peak. |
| D4 | Gate Pwr Fault: The power supply which sets up isolated gate supply voltages and the ± 15V for the Current Transformer and the OP amps, is at under voltage |
| D5 | Temperature Fault: Temperature of heatsink is beyond limits |
| D6 | Config_OK: Always on if the configuration is OK. |
Digital Gate Logic Board Diagram
 | |
| Illustration 2 | g01280991 |