GE IS200DSFCG1A Driver Shunt Feedback Board

The IS200DSFCG1A is a 1000/1800 Amp IGBT Gate Driver/Shunt Feedback Board designed by General Electric (GE) for its Innovation Series™ product line. This board is a critical component within the DSFC series, primarily used in Pulse Width Modulated (PWM) source bridges and AC drive systems. The DSFCG1A integrates a current sensing circuit, a fault detection circuit, and two IGBT gate drive circuits. Both the driver and feedback circuits utilize galvanic and optical isolation technologies to ensure safe isolation between high-voltage and low-voltage sides.

This board is specifically designed for drive/source applications with 600 V LL rms AC input and supports drive systems rated for both 1000 Amp and 1800 Amp current levels. In a 1000 A system, one DSFC board is required per phase, totaling three boards. In an 1800 A system, two DSFC boards connected in a "daisy chain" configuration are required per phase, totaling six boards. The DSFCG1A interfaces with the drive control system via the IS200BPIB Drive Bridge Personality Interface Board (BPIB).

The DSFCG1A board is mounted directly onto the upper and lower IGBT modules of each phase leg to ensure that gate drive output and shunt input connections are as short as possible, thereby minimizing parasitic inductance and signal interference. The board is secured to the IGBTs via gate, emitter, and collector connections. Proper orientation of the board's mounting holes during installation is essential.

II. Main Functions

The primary functions of the IS200DSFCG1A include, but are not limited to, the following:

1. Output Phase Gate Drive

• Provides two isolated IGBT gate drive circuits: one controlling the upper IGBT(s) of a phase leg, the other controlling the lower IGBT(s).

• Each drive circuit can drive two paralleled IGBT modules.

• Drive voltage range is VCC (+15 V) to VEE (-15 V), with the IGBT emitter as common.

• Peak source/sink current capability is up to 20 Amps.

• Maximum PWM chopping frequency is 6 kHz.

• Drive control optocoupler input diodes are connected in an anti-parallel configuration, enabling control of both upper and lower IGBTs from a single differential twisted-pair control line.

• The board's gate series resistors and gate-emitter capacitors are specifically sized for the IGBT modules.

2. Fault Detection and Reporting

The DSFCG1A can detect two types of faults: Desaturation Fault and Undervoltage Fault. These faults are reported through a single "multiplexed" differential fault line covering both upper and lower IGBT circuits.

• Desaturation Fault: When the driver is commanded to turn the IGBT ON, the voltage drop across the IGBT's emitter-collector is monitored. If this voltage exceeds 10 V for 4 microseconds, a desaturation fault is triggered. Upon a desaturation fault, the BPIB board operates the DSFC board in a "burst" mode, using a 2 MHz PWM signal to slowly bring the gate voltage down to zero within 2 to 5 microseconds.

• Undervoltage Fault: The voltage between the positive drive power supply (+15 V) and the negative drive power supply (-15 V) is monitored. If this voltage drops below 20 V, an undervoltage fault is triggered.

Fault signals are logically ORed, optically isolated, and reported to the control logic via a differential driver interface. In the normal (OK) state, the optocoupler is ON (output low).

3. Shunt Current Feedback

Output phase current is monitored by sensing the voltage drop across the phase shunt. This voltage is amplified and fed to a Voltage Controlled Oscillator (VCO) circuit. The VCO frequency range is 0 to 2 MHz, with the circuit biased to output 1 MHz at zero current. A ±200 mV change in shunt voltage is converted into a ±800 kHz change in VCO output frequency. The VCO output is optically isolated and transmitted to the control logic via a differential driver interface.

The current feedback circuit can generate two types of faults:

• DI/DT Fault: A 100% or greater step change in the rated shunt current will cause a DI/DT fault to be reported within 25 microseconds.

• Instantaneous Overcurrent (IOC) Fault: An IOC fault is reported when the current exceeds a set threshold.

4. Power Supplies

The high-voltage side of the driver/monitor circuits is powered by an isolation transformer. The primary of this transformer is connected to a ±17.7 V peak (35.4 V peak-to-peak), 25 kHz square wave. Among the three secondary windings:

• Two secondaries are half-wave rectified and filtered to provide isolated +15 V (VCC) and -15 V (VEE) required by the upper and lower IGBT driver circuits (unregulated, ±5%, 1 A average maximum each).

• The third secondary is full-wave rectified and filtered to provide isolated ±12 V required by the shunt current feedback VCO and fault detection circuitry (unregulated, ±10%, 100 mA average maximum each).

• The shunt circuit also requires a 5 V logic supply, generated by a 5 V linear regulator connected to the +12 V supply (±10%, 100 mA average maximum). Only the 5 V power supply is regulated.

Maximum loads are as follows:

• ±17.7 V: 0.65 A rms

• +5 V: 150 mA

5. LED Status Indicators

The DSFCG1A board features five LED indicators for displaying DC link and IGBT driver status:

III. System Applications

1. Application in Drive Systems

The IS200DSFCG1A is an essential component in GE Innovation Series™ PWM drive systems. Its roles within the system include:

• Gate Driving: Provides reliable turn-on and turn-off drive signals to IGBT modules, ensuring proper operation of power switches.

• Current Feedback: Precisely measures phase current via a shunt and converts the current signal into a frequency signal for closed-loop control by the control system.

• Fault Protection: Continuously monitors IGBT operating status, rapidly reporting faults such as desaturation, undervoltage, or overcurrent to protect power devices and the load.

2. System Configuration

• 1000 A System: Uses 1 DSFCG1A board per phase, 3 boards total for three phases. Each board connects to the BPIB board via the PPL1 connector.

• 1800 A System: Uses 2 DSFCG1A boards per phase, connected in a daisy chain. The master board connects to BPIB via PPL1; the slave board connects to the master's PPL1 via its PPL2 connector for signal pass-through.

3. Typical Application Scenarios

• Industrial AC Variable Frequency Drives

• PWM Power Inverters

• Motor Control Centers

• Excitation Control for Power Generation Systems

• Railway Traction Systems

• Marine Electric Propulsion Systems

IV. Installation and Wiring Instructions

1. Mounting Location

The DSFCG1A board mounts directly onto the IGBT modules. During installation, ensure the eyelets on the board align correctly with the gate, emitter, and collector pins/studs of the IGBT modules. Secure the board using the provided hardware to ensure reliable electrical connections.

2. Installation Steps

1. Ensure the drive system is powered OFF and allow sufficient time (several minutes) for capacitors to discharge.

2. Open the drive cabinet door and locate the DSFC board to be installed or replaced.

3. Align the DSFC board over the IGBT mounting studs, ensuring all eyelets fit correctly.

4. Secure the board using the 10 nuts, torquing them to 70 in-lbs.

5. Reconnect all cables according to their labels, ensuring connectors are fully seated.

3. Wiring Description

• Stab-on Terminals: Used for connecting DC link and output phase voltage sensing lines.

• E1: Output Phase Voltage Sensing Line (MVFB)

• E17: DC Link Positive (DCLP)

• E18: DC Link Negative (DCLN)

• IGBT Mounting Eyelets: Used for connections to IGBT gate, emitter, and collector.

• UC: Upper Collector Link (DC link positive)

• UGA/UEA: Upper A Device Gate/Emitter

• UGB/UEB: Upper B Device Gate/Emitter

• LGA/LEA: Lower A Device Gate/Emitter

• LGB/LEB: Lower B Device Gate/Emitter

• LE: Lower Emitter Link (DC link negative)

• Plug Connectors:

• PPL1: Connects to the BPIB board, carrying drive signals, fault signals, VCO signals, and power.

• PPL2: Connects to the next DSFC board in a daisy chain (used only in 1800 A systems).

• SHPL: Connects to the current shunt, input for shunt voltage signal.

• THPL/THPL1/THPL2: Connections for Resistance Thermal Detectors (RTD) or pass-through connections for daisy-chaining.

• DPPL1/DPPL2: Receives 18.4 V AC peak square wave power from BPIB, or acts as a power pass-through for daisy-chaining.

  
  

V. Diagnostics and Maintenance

1. Status Indication

System status can be quickly assessed via the five on-board LEDs:

• DS1 (Red): DC Link Voltage Indicator. Should be ON during normal operation when bus voltage exceeds 50 V.

• DS2/DS3 (Green): Upper/Lower IGBT OFF Status Indicators. ON when IGBTs are driven OFF, OFF when driven ON.

• DS4/DS5 (Yellow): Upper/Lower IGBT ON Status Indicators. ON when IGBTs are driven ON, OFF when driven OFF.

During normal PWM operation, DS2 and DS3 may be ON constantly or alternate with DS4/DS5 depending on the state, while DS4 and DS5 should flash corresponding to the PWM pulses.

2. Fault Diagnosis

The DSFCG1A provides comprehensive fault detection, readable via the BPIB board:

• Desaturation Fault: Typically indicates IGBT overcurrent or short circuit. Check the load and IGBT modules.

• Undervoltage Fault: Indicates insufficient drive power supply voltage. Check the power supply circuit.

• DI/DT Fault: Indicates an excessive rate of current change, possibly due to load transients or control anomalies.

• IOC Fault: Indicates instantaneous overcurrent. Check the load and current feedback circuit.

3. Maintenance Precautions

• Adhere to ESD (Electrostatic Discharge) precautions when handling the board. Wear a grounding strap and store boards in anti-static bags.

• Do not connect or disconnect cables while power is applied, to prevent board damage or safety hazards.

• Periodically inspect connectors for looseness and verify normal LED operation.

• When replacing a board, ensure the new board has the correct model number (IS200DSFCG1A) and pay attention to mounting orientation and torque specifications.