Inverters

Inverters are used to create single or poly-phase alternating current voltages from a Direct Current supply. The typical inverter for motor drives is a “hard-switched” voltage source inverter producing pulse-width modulated signals with a sinusoidal fundamental. Multilevel inverters besides their larger voltage and power ratings also inherently avoid this problem. A very common application for single-phase inverters is a so-called uninterruptible power supply for computers and other critical loads. In addition to the very common hard-switched inverters, active research is being conducted on “softswitching” techniques. A separate class of inverters is the line-commutated inverters for multimegawatt power ratings that use thyristors. Inverters fall in the class of power electronics circuits. The most widely accepted definition of a power electronics circuit is that the circuit is actually processing electric energy rather than information. The driver circuit will typically add some additional blanking time during the switch transitions to avoid any overlap in the conduction intervals.