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[[File:Three leg inverter.gif|240px|thumb|right|Topology of a basic three phase inverter.]]
A three phase inverter as shown to the right converts a DC supply, via a series of switches, to three output legs which could be connected to a three-phase motor.
The switches must be controlled so that at no time are both switches in the same leg turned on or else the DC supply would be shorted. This requirement may be met by the complementary operation of the switches within a leg. i.e. if A<sup>+</sup> is on then A<sup>−</sup> is off and vice versa. This leads to eight possible switching vectors for the inverter, V<sub>0</sub> through V<sub>7</sub> with six active switching vectors and two zero vectors. <center>
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Note that looking down the columns for the active switching vectors V<sub>1-6</sub>, the output voltages vary as a pulsed sinusoid, with each leg offset by 120 degrees of [[Phasor_(electronics)|phase angle]].
To implement space vector modulation a reference signal V<sub>ref</sub> is sampled with a frequency f<sub>s</sub> (T<sub>s</sub> = 1/f<sub>s</sub>). The reference signal may be generated from three separate phase references using the [[Alpha beta gamma transform|<math>\alpha\beta\gamma</math> transform]]. The reference vector is then synthesized using a combination of the two adjacent active switching vectors and one or both of the zero vectors. Various strategies of selecting the order of the vectors and which zero vector(s) to use exist. Strategy selection will affect the harmonic content and the switching losses.
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