Hybrids and EVs have a substantial requirement for power conversion; a drive train can be operated up to 100s of kW. A typical silicon-based converter will be no more than 95% efficient, Pi Innovo says, therefore having at least a 5% loss. These losses, as heat, have to be dissipated.

Moreover, silicon efficiency of 95% is only achieved at optimum full load and can drop to as low as 70% at lower, more common driving loads. Gallium nitride devices can maintain an efficiency of 90% even at low loads due to the smaller drive circuit losses.

Gallium nitride semiconductor based converters can achieve 98 to 99% efficiency—a threefold reduction in losses at typical operating voltages. GaN can operate at higher junction temperatures and can be air-cooled rather than water-cooled.

GaN circuits can also easily be driven in parallel for high-current operation. With higher switching frequency, there is opportunity for more efficient operation at high motor speeds even with high pole count. A wide temperature range allows co-packaging with the motor and a wide input voltage range can be achieved with very similar electrical architecture.

GaN Systems’ compound semiconductor devices are cost-competitive with silicon devices, while offering superior performance; these gallium nitride devices use low cost GaN-on-silicon base wafers.

Left. Pi Innovo 1.5 kW BLDC (Brushless DC) motor driver incorporating six GaN Systems GS66508T transistors. The prototype has voltage and current feedback for each of the 3 motor phase control half bridges. It is circular in shape to depict an application in which the controller PCB would be mounted onto the end of the motor assembly. The GaN Demo PCB is capable of driving motors up to 1.5 kW at 300 V while having a diameter of only 4". It has a power density 5x that of existing 12 V BLDC motor controllers. Right. With the heat sink applied. Click to enlarge.

Pi Innovo has designed and implemented custom motor control electronics to take advantage of the benefits of GaN semiconductors in applications with a wide range of input voltages from 12V to 300V, making the design ideally suited to the electrification of auxiliary vehicle systems on multi-voltage conventional, hybrid-electric and pure electric vehicles. This controller design provides a functional starting-point for the development of 48V and above high-speed motor-driven vehicle systems.

Following the success of this GaN-based multi-voltage motor controller development project, Pi Innovo is now offering design and development services in support of customers looking to adopt this technology for a wide range of electronics design applications in automotive and adjacent markets.

The company is positioned to support customers wanting to develop prototype evaluations to quantify the benefits of GaN technology. Pi Innovo can also provide customized cost-effective high volume designs for customers looking to go into production.

Pi Innovo’s hardware, software and applications engineers worked closely with the GaN Systems team to understand their semiconductor design requirements and to ensure the final controller design maximizes the reduction in size, weight and power consumption benefits that gallium nitride semiconductors provide. Working with GaN Systems on this project has been a great experience for our team and we’re looking forward to continuing our close partnership to support our customers on many future designs.

—Dr. Walter Lucking, CEO of Pi Innovo

Having a technology development partner like Pi Innovo that really understands the intricacies of control electronics design for vehicle applications, is invaluable in supporting the continued adoption of GaN in the electrification of vehicle systems.

—Jim Witham, GaN Systems’ CEO

An example of a Pi Innovo GaN motor controller is on show this week at APEC 2016 in Long Beach, CA.