Improved dead-time elimination method for three-phase power inverters

Abstract

In real inverters' operations, it is essential to insert delay time in the pulses provided to the inverter switches to protect the DC link against the short circuits. From this situation, the dead time phenomenon is introduced that causes undesirable performance and distortion of the output signal. Previously, researchers have proposed various schemes for compensating or eliminating dead-time. In this paper, a new dead-time elimination (DTE) scheme is proposed with a guarantee algorithm to eliminate dead-time and overcome the issues produced at the zero-currents-crossing point (ZCC). This method does not require additional hardware or filters to determine the polarity of the output current, and its principle is very simple to implement. The developed DTE method completely removes the dead-time issues on the magnitude and phase of the output voltage, and avoid the problems which can be induced around the ZCC. The results confirm the effectiveness and safety of this method.

Estimation Technique for IGBT Module Junction Temperature in a High-Power Density Inverter

“…Inverters for traction motor applications require dead time (t d ) to prevent crossconduction, which occurs when the upper and lower arms of the IGBT generate a direct short-circuit across the power supply and GND lines [34,35]. As shown in the waveforms in Figure 7, the dead time is the time when both the upper-arm and lower-arm IGBTs are turned off, and the dead time is inserted to force off both the upper-arm and lower-arm IGBTs to ensure they are never on simultaneously while switching [36]. Assuming that the inverter is working in linear modulation mode with inverter modulation index m, frequency ω, load voltage-current angle Փ, and dead time td as shown in Figure 7, the conduction time of the transistor (tcon_T(t)) and diode (tcon_D(t)) during one switching period tsw can be computed as follows: Assuming that the inverter is working in linear modulation mode with inverter modulation index m, frequency ω, load voltage-current angle Φ, and dead time t d as shown in Figure 7, the conduction time of the transistor (t con_T (t)) and diode (t con_D (t)) during one switching period tsw can be computed as follows:…”