Europe embraces wide-bandgap semiconductors

May 30, 2017 OpenSystems Media

Disruptive forces are going through the power electronics industry, driving development and challenging manufacturers to keep up with the latest in materials, topologies, and technologies. Digitally-enabled power systems, advanced topologies, and wide-bandgap semiconductors are moving the industry forward, leveraging one another to create the next generation of power infrastructure.

The recent Power Control and Intelligent Motion (PCIM) conference in Nuremberg was a cavalcade of engineering demonstrations, each showing solutions based on one or all of the disruptive technologies now available. The greatest buzz was around Silicon Carbide (SiC) and Gallium Nitride (GaN), as many vendors had a demo or static display showing they were a part of the hottest trend.

SiC and GaN

It’s easy to say that replacing SiC devices with GaN transistors can increase power densities by 4X or more while simultaneously reducing system weight and cost, and another to see real products demonstrating advanced performance. GaN Systems was one of the several wide-bandgap developers showing customer systems exhibiting previously unattainable power densities. One such product was a 200-W AC adapter provided by 3NERGY with a tiny form factor, roughly one-third the size of conventional adapters based on legacy silicon (Figure 1).

[Figure 1 | This GaN-based 200-W AC adapter from 3NERGY has a form factor that’s about one-third the size of conventional products.]

I ran into Stephen Oliver from Navitas Semiconductor, who was on his way to participate in a panel discussion on providing insight into designing with GaN and SiC for the “newly interested.” He explained that the increases in switching frequency and system efficiency enabled by GaN power ICs have not only created new power density benchmarks, they’ve enabled designers to do so while maintaining or even reducing a product’s thermal specs.

Transphorm demonstrated high-voltage GaN FETs used in power electronics systems, and showcased its new AEC-Q101 qualified GaN FET, presented as the industry’s first automotive-grade GaN technology. Another industry first was claimed by a GaN servo motor targeting 100 to 400-W applications. The Yaskawa integrated servo motor uses GaN FETs to increase system power density and efficiency, simplify system architecture, and deliver a dramatic reduction in system size (Figure 2).

[Figure 2 | The Yaskawa integrated servo motor uses GaN FETs to increase system power density and efficiency and simplify system architecture.]

Alex Lidow from Efficient Power Conversion was also presenting at PCIM, demonstrating the ability of eGaN FETs to be employed in a class-E wireless energy transfer system with a 20% improvement in peak efficiency over a voltage-mode class-D version using the same coils and device load. The experimental example demonstrates why eGaN FETs attributes like low input and output capacitance, and low package inductances make them ideal for wireless power systems. EPC also unveiled an even more efficient topology for improved stability and reduced component counts compared with the Class E example.

Embedded advances

Beyond materials, new devices and technologies for better power systems were also abundant. On Semiconductor, for example, showed its new synchronous rectifier (SR) controller optimized for LLC resonant converter topologies. It has separate inputs to accurately sense the drain and source voltages across the two SR MOSFETs, allowing for any asymmetries or poor coupling in the secondary winding. This prevents current inversion and avoids SR mis-triggering due to capacitive current spikes. The anti-shoot-through control within the controller enhances the PSU’s reliability and prevents potentially destructive simultaneous turn-on of the two SR MOSFETs (Figure 3).

[Figure 3 | On Semiconductor’s new synchronous rectifier (SR) controller, optimized for LLC resonant converter topologies, targets high-performance power applications.]

Vicor detailed its recent research on how engineers’ biggest challenges are downstream spec changes after the design process has begun. According to the survey, 87% of power system designers around the world identified changes as the most frequent impediment in designing power systems. The research also highlights the challenges of meeting project timelines. 80% of power engineers are already struggling to meet time constraints when designing power systems and 79% feel that project schedules are tighter due to time-to-market pressures. Spec changes negatively impact schedules according to 65% of engineers. Vicor pointed out its online tools and scalable systems can significantly reduce this pressure by giving engineers more and faster design flexibility.

Even though the company had lots of wide-bandgap products at its their booth, Infineon Technologies introduced new products based on silicon. The CIPOS mini intelligent power module combines a single switch-boost PFC stage and a three-phase inverter in one package. While its high integration help reduces system size and BOM, the IPM features a Trenchstop IGBT combined with an optimized silicon on isolator (SOI) gate driver, and is especially designed for power applications that need good thermal conduction and electrical isolation.

For even more info, check out our recent podcast on the PCIM Europe show.

Alix Paultre
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