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Gallium nitride (GaN) devices are becoming more popular in power semiconductor converters. Due to the absence of the freewheeling substrate diode, the reverse conduction region is used in GaN transistors to conduct the freewheeling current. However, the voltage drop across the device in the reverse conduction mode is relatively high, causing additional power losses. These losses can be optimized by adequately adjusting the dead-time issued by the microcontroller. The dead-time loss minimization strategies presented in the literature have the common disadvantage that either additional hardware or specific converter data are needed for their proper operation. Therefore, this paper’s motivation is to present a novel dead-time loss minimization method for GaN-based high-frequency switching converters for electric drives that does not impose additional requirements on the hardware design phase and converter data acquisition. The method is based on optimizing the current controllers’ output with a simple perturb-and-observe tracker. The experimental results show that the proposed approach can minimize the dead-time losses over the whole drive’s operating range at the cost of only a moderate increase in software complexity.
Pavel Skarolek; Filipp Frolov; Ondrej Lipcak; Jiri Lettl. Reverse Conduction Loss Minimization in GaN‑Based PMSM Drive. Electronics 2020, 9, 1973 .
AMA StylePavel Skarolek, Filipp Frolov, Ondrej Lipcak, Jiri Lettl. Reverse Conduction Loss Minimization in GaN‑Based PMSM Drive. Electronics. 2020; 9 (11):1973.
Chicago/Turabian StylePavel Skarolek; Filipp Frolov; Ondrej Lipcak; Jiri Lettl. 2020. "Reverse Conduction Loss Minimization in GaN‑Based PMSM Drive." Electronics 9, no. 11: 1973.
This paper describes a switching pattern generated in case of induction motor drive predictive torque control (PTC) compared to a switching pattern of direct torque control (DTC). PTC is a modern control method for electric drives based on model predictive control (MPC). DTC is a very powerful method and is today an industrial standard for controlling an induction motor drive. Its usage is wide-spread, mainly in high-power applications. However, the method suffers from a few disadvantages. One of the causes of the control method’s problematic behavior is choosing the switching combinations in the flux sector. Another inconvenience is the common selection table not including all voltage vectors in given sector. By these factors, the ripples of flux vector trajectory and torque waveforms are influenced. The longer the sample time is, the more significant the influence of factors becomes, because only a few steps occur within one turn of the magnetic flux vector. Based on the detailed analysis, the reasons of the different performance of both systems are explained. The analysis performed by simulation in Matlab Simulink environment has proved that, while DTC might choose voltage vector that pushes system away from the reference values, the MPC always chooses the most proper vector. The experimental results measured on the real drive confirm the appropriate vector selection, just in case of the predictive control method.
Pavel Karlovsky; Jiri Lettl. Induction Motor Drive Direct Torque Control and Predictive Torque Control Comparison Based on Switching Pattern Analysis. Energies 2018, 11, 1793 .
AMA StylePavel Karlovsky, Jiri Lettl. Induction Motor Drive Direct Torque Control and Predictive Torque Control Comparison Based on Switching Pattern Analysis. Energies. 2018; 11 (7):1793.
Chicago/Turabian StylePavel Karlovsky; Jiri Lettl. 2018. "Induction Motor Drive Direct Torque Control and Predictive Torque Control Comparison Based on Switching Pattern Analysis." Energies 11, no. 7: 1793.