www.microchip.com AEROSPACE 17 www.power-mag.com Issue 3 2023 Power Electronics Europe addition, the low-inductance and low-profile package can be soldered directly on the PCB, accelerating the development and increasing the reliability. Believed to be the first aerospacequalified low profile, low weight power module technology to serve aerospace applications, the family includes three sizes of power modules (BL1, BL2, and BL3). The standard configuration integrates 1.2kV full-SiC topologies, with or without freewheeling diodes. The modules are available as 75A and 145A SiC MOSFETs, 50A IGBTs and 90A rectifier diode outputs. IGBT-based and custom solutions containing devices with voltage ratings from 700V to 1,700V are also available. Depending on the specific version, different topologies are supported, such as full bridge, asymmetrical bridge, phase leg, dual common source, buck, and boost. Figure 2 shows the phase leg topology supported by the BL1 power module (1200V, 79A, RDS(on) typical 25mΩ). The SiC power MOSFET features low RDS(on) and high switching frequency, while the SiC Schottky diode provides zero reverse- and forward-recovery and temperatureindependent switching behaviour. The full bridge topology, shown in Figure 3, is supported by both the BL2 and BL3 power modules. These modules feature a drain-source voltage of 1.2kV, continuous drain current up to 150A at ambient temperature (up to 300A of pulsed drain current), and drain-source onresistance as low as 16mΩ. The SiC MOSFET features a Kelvin source for easy drive, and the SiC Schottky diodes also feature zero reverse- and forwardrecoveries. Maximum power is 560W, while maximum gate-source voltage is -10V (off state) and 24V (on state). Qualification tests All of the BL1, BL2, and BL3 power modules have undergone qualification tests to demonstrate the ability to serve aerospace applications. The Acceptance Test Procedure, based on the conditions specified in RTCA DO-160G and in compliance with civil aircraft environmental conditions, included parametric test over the full voltage, current, and temperature range (–55˚C, 25˚C and 125˚C), partial discharge test (10pC max at 1200V AC), hipot (3kV AC) and isolation resistance test (>100 MR at 500V DC). The following tests have been performed: High temperature gate bias. The purpose of this test, performed at both VGS = 20V and VGS = -8V, is to verify that the device performance is not affected by high temperature gate bias. At a junction temperature of 175˚C, the Vth measurements before and after 1,000 hours of high temperature gate bias stress show negligible variations. Temperature cycling. This test aims to assess the resistance of the device to extreme high and low temperatures. The X-rays and scanning electron microscopy analysis, performed after 1,000 cycles Figure 1: The BL3 Low profile, low weight power module Figure 2: Phase leg topology supported by the BL1 power module Figure 3: Full bridge topology (dual phase leg) available in the BL2 and BL3 modules
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