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.

This paper describes two alternative variable speed motor drive systems for washing machine applications. Three phase induction motors with tachometer feedback and direct drive permanent magnet synchronous motors with hall sensor feedback are two drive systems commonly used in North American washers today. Appliance manufacturers are now evaluating sensorless drive systems because of the low reliability and high cost of the speed and position feedback sensors. A Field Oriented Control Algorithm with an embedded rotor flux and position estimation algorithm enables sensorless control of both permanent magnet synchronous motors and induction motors. The estimator derives rotor shaft position and speed from rotor flux estimates obtained from measured stator currents and the applied voltages. Sampling of currents in the dc link shunt simplifies stator current measurement and minimizes cost. Field oriented control algorithm allows good dynamic control of torque and enables an extended speed range through field weakening. The digital control algorithm runs on a unique hardware engine that allows algorithms to be designed using graphical tools. A common hardware platform can run either the PMSM or IM using sensorless field oriented control in a front loading washer application. Test results are presented for both drives in standard wash cycles.

Today's solutions for motor control applications require more flexibility and a higher level of integration that could be achieved only through specialized products. This paper presents the analysis of the first results obtained from a new family of intelligent power modules developed specifically for servo motor drive applications. The module's architecture includes several key design features needed in these applications, such as motor phase current sensing, DC bus voltage control and short circuit protections while the embedded DSP allows easy realization of the current loop and even speed loop at the module level without any external components.

This paper deals with the modelling of saturable inductors with ferrite core applied in a high frequency synchronous step-down converter, with GaN FETs as switches. The inductor current waveform is modeled and simulated under non-linear conditions, in order to evaluate the dynamic performances and the converter efficiency. The inductor current waveform is analyzed under different loads conditions at a fixed switching frequency. Furthermore, variable switching frequency simulations under fixed load conditions are carried out.

This paper investigates the commutation transients of MOSFET and GaN FET devices in motor drive applications during hard-switching and soft-switching commutations at dead time operation. This study compares the switching behaviors of MOSFETs and GaN FETs, focusing on their performance during dead time in inverter legs for voltage source inverters. Experimental tests at various phase current levels reveal distinct switching characteristics and energy dissipation patterns. A validated simulation model estimates the experimental energy exchanged and dissipated during switching transients. The results demonstrate that GaN FETs exhibit lower overall losses at shorter dead times compared to MOSFETs, despite higher reverse conduction voltage drops. The study provides a quantitative framework for selecting optimal dead times to minimize energy losses, enhancing the efficiency of GaN FET-based inverters in low-voltage motor drive applications. Finally, a dead time optimization strategy is proposed and described.