Editing Power inverter (section)

====Near sine wave PWM====
[[File:PWM, 3-level.svg|thumb|right|upright=1.5|An example of PWM voltage modulated as a series of pulses {{colorbull|blue}}. Low pass filtering with series [[inductor]]s and shunt [[capacitor]]s is required to suppress the switching frequency. Once filtered, this results in a near sinusoidal waveform {{colorbull|red}}. The filtering components are smaller and more convenient than those required to smooth a modified sine wave to an equivalent harmonic purity.]]

Some inverters use [[pulse-width modulation|PWM]] to create a waveform that can be low pass filtered to re-create the sine wave. These only require one DC supply, in the manner of the MSN designs, but the switching takes place at a far faster rate, typically many kHz, so that the varying width of the pulses can be smoothed to create the sine wave. If a microprocessor is used to generate the switching timing, the harmonic content and efficiency can be closely controlled.