Inverters are circuits for converting a direct current (DC) to an alternating current (AC). That is, an inverter converts direct current electric energy from a source, such as a battery, to an alternating current, which is generally a sine wave or square wave. One particular type of inverter is a multi-level inverter that is configured to first convert a direct current into a step-like square wave of multiple levels, and then form a sine wave by using a filter. If there are more levels implemented by the multi-level inverter, a waveform of a sine wave that is obtained by the multi-level inverter is more approximate to a standard sine waveform.
In terms of topology varieties, multi-level inverters take many forms, such as diode-clamped multi-level inverters, flying capacitor multi-level inverters, and others (e.g. cascaded H-bridge multi-level inverters, etc.). Unlike flying capacitor multi-level inverters which typically employ capacitors for clamping purposes, diode-clamped multi-level inverters use diodes to provide multiple voltage levels through different phases to capacitor banks. In use, the diode transfers a limited amount of voltage, thereby reducing the stress on other electrical components.
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