Asymmetrical Switching Loops in Three-Level Voltage Inverters

Abstract: This article considers the first-ever Russian hybrid power module design for three-level voltage inverters made with a fixed neutral-point-clamped circuit. The operational features of this circuit are considered from the standpoint of problems characteristic of multichip power microassemblies. One of the main engineering problems in creating a three-level power module is asymmetrical switching loops and the high sensitivity of its circuit to installation inductances. Apart from the task of reducing the parasitic inductance of mounting connections, the additional problems with creating the hybrid three-level module design are dynamic overvoltage restrictions in the key components of the circuit, voltage leveling in the key components of the circuit in static mode, and elimination of unevenness in the heat losses dissipated in the circuit. The characteristics of placing three-level microassemblies in standard low-profile cases are considered. Design configurations with mounting connections based on strip buses with reduced parasitic inductance are presented. The characteristics of applying resonant switching to the three-level circuit are considered for eliminating unevenness in the thermal overheating of the key components. It is shown that the energy of dynamic losses in the three-level system is efficiently reduced by meeting several conditions the main one of which is the possibility of technology control over the parameters of the reactive components of the hybrid design. © 2019, Allerton Press, Inc.