Abstract
The efficiency and power density improvement of power switching converters play a crucial role in energy conversion. In the field of motor control, this requires an increase in the converter switching frequency together with a reduction in the switching legs’ dead time. This target turns out to be complex when using pure silicon switch technologies. Gallium Nitride (GaN) devices have appeared in the switching device arena in recent years and feature much more favorable static and dynamic characteristics compared to pure silicon devices. In the field of motion control, there is a growing use of GaN devices, especially in low voltage applications. This paper provides guidelines for designers on the optimal use of GaN FETs in motor control applications, identifying the advantages and discussing the main issues. In this work, primarily an experimental evaluation of GaN FETs in a low voltage electrical drive is carried out. The experimental investigation is obtained through two different experimental boards to highlight the switching legs’ behavior in several operative conditions and different implementations. In this evaluative approach, the main GaN FETs’ technological aspects and issues are recalled and consequently linked to motion control requirements. The device’s fast switching transients combined with reduced direct resistance contribute to decreased power losses. Thus, in GaN FETs, a high switching frequency with a strong decrease in dead time is achievable. The reduced dead time impact on power loss management and improvement of output waveforms quality is analyzed and discussed in this paper. Furthermore, input filter capacitor design matters correlated with increasing switching frequency are pointed out. Finally, the voltage transients slope effect (dv/dt) is considered and correlated with low voltage motor drives requirements.
Highlights
The increased switching frequency allowed by the high electron mobility transistors (HEMT) devices beyond a certain level is not always a winning design choice
This paper describes the advantages and issues to be solved when using Gallium Nitride (GaN) FETs in applications of low voltage electric drives currently widely used in industrial, robotic and automotive fields
The technology of the device is described in relation to the considered application, highlighting the characteristics and parameters of the GaN FET that mainly affect the operation of the inverters when they are used as power switches
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. In low voltage applications for power ratings up to 400 W, there are integrated switching leg solutions which include a driver circuit in the same package. Wide bandgap (WBG) GaN devices allow higher switching frequency in inverter topologies for drive applications compared with silicon MOSFETs. The switching frequency increase leads to some advantages. The main advantages and disadvantages of GaN FETs in inverter topologies for low voltage high dynamic performance electrical drives are analyzed and discussed.
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