Three Phase Inverter

Three Phase Inverter

Three Phase Inverter is an electronic device or circuitry that changes D.C voltage into three phase a.c voltage having a phase difference of 120^o or 240^o .

Figure besides present the electronic circuit schematic for three phase inverter:

Let ‘O’ be the midpoint of D.C supply which is shown grounded in the figure. So, the potential of that point is zero.Basically, it is the combination of single phase inverter supplied from common DC source and each set conducted with a phase difference 120^o to each other with the consideration of three-phase balanced load connected to the three phase inverter.

V_R = Potential of Point A with respect to zero

V_Y = Potential of Point B with respect to zero

,V_B = Potential of Point C with respect to zero

According to the definition of the Three Phase Inverter, the output of the point A, point B and point C with respect to zero is shown in the figure below.

For three-phase balanced load,

V_RN + V_YN + V_BN = 0

The per phase voltage is defined as

V_RN = V_R - V_N; V_YN = V_Y - V_N; V_BN = V_B - V_N

Substituting in the above equation, we get

V_N = 1/3(V_{R + VY + VB})

The per phase waveform of R-phase and Waveform of the voltage at the neutral point is plotted from the above equation.