Module Marvel: Single-Board Gate Drivers Simplify High-Voltage IGBT Design
Power Integrations’ dual-channel gate drivers are single-board, plug-and-play IGBT driver solutions that mount directly to the power module, saving space and reducing design complexity.
Power Integrations has released the SCALE-iFlex XLT of single-board gate driver series for “new dual” style high-voltage IGBT (insulated-gate bipolar transistor) modules. The dual-channel drivers are designed for power conversion applications in wind, energy storage, and solar power generation systems and can provide up to 2300 V of blocking voltage.
The gate drivers are designed to mount on top of a standard IGBT power module and fit within the module’s mechanical dimensions, saving space and simplifying mechanical designs. Using Power Integrations’ SCALE-2 chipset reduces component count and improves the drivers’ reliability.
A dedicated NTC (negative temperature coefficient) data readout channel allows accurate module temperature measurements to be captured directly from the power module’s onboard NTC sensor. This temperature data, relayed across the isolation barrier, improves thermal management, allowing for 25 to 30 percent higher power levels without needing additional high-voltage isolation circuitry.
The SCALE-iFlex XLT gate driver family is compatible with single LV100 (Mitsubishi), XHP 2 (Infineon), HPnC (Fuji Electric), and equivalent IGBT power modules.
SCALE-iFlex XLT gate driver mounted to an IGBT module. Image used courtesy of Power Integrations
Solar Inverters
Solar power generation plants use photovoltaic arrays to convert solar energy to high-voltage DC power. To transfer this power to the grid or directly to power loads, the solar panels’ DC voltage is converted to AC through an inverter circuit.
High-voltage (up to 2000 V or more) IGBT bridge modules are commonly used to construct solar inverter circuits. They require specialized gate drive circuitry to isolate the gate drive controller from the high-voltage switches, allowing drive control signals to pass across the isolation boundary.
High-voltage solar inverter circuit. Image used courtesy of Fuji
SCALE-iFlex XLT Gate Driver
The SCALE-iFlex XLT is a single-board, dual-channel gate driver module consisting of an input connector assembly, transformer-isolated DC-DC converter, and screw connections for the emitter, gate, and collector of the high-side and low-side IGBTs.
The input connector provides 15 V power for the primary side electronics and onboard DC-DC converter, along with command input and status output signals for both the high- and low-side switches. The DC-DC converter provides isolated (up to 2300 V) gate drive power (-8 A, 1W) to the IGBTs to turn the switches on and off as needed.
The module’s onboard NTC sensor interface is through a separate screw connector. Temperature data is relayed across the isolation boundary and through the TPM pin of the input connector to the system controller for continuous monitoring.
SCALE-iFlex XLT gate driver board. Image used courtesy of Power Integrations
Protection Features
The SCALE-iFlex XLT gate driver uses the module’s IGBT switches’ desaturation properties to detect and protect against short circuit conditions. To do this, the gate driver monitors for desaturation conditions by measuring the collector-emitter voltage (VCE) through a resistor sensing network. If VCE exceeds a programmed threshold after a specified response time (tRES) from the device turn-on, a short-circuit condition is indicated, and the switch is immediately turned off. A fault signal is transmitted to the system controller via the module interface connector.
IGBT desaturation characteristics. Image used courtesy of TI
Creepage and clearance distances for the gate driver PCB and transformer meet IEC 61800-5-1 standards for reinforced isolation in the 1700 V modules and basic isolation for 1200 V power modules.