.Modelica.Electrical.PowerConverters.DCAC.Control.SVPWM

Information

For a threephase system, 8 space vectors are available according to the following switching patterns:

• 0 [0,0,0] length 0
• 1 [1,0,0] 000°
• 2 [1,1,0] 060°
• 3 [0,1,0] 120°
• 4 [0,1,1] 180°
• 5 [0,0,1] 240°
• 6 [1,0,1] 300°
• 7 [1,1,1] length 0

Vector 1..6 form a hexagon, vector 0 and 7 are of length 0.

First, the space vector is limited, and the sector of the hexagon is determined where the input space vector u is located; then the angle of the space vector within this sector 0≤φ<60° is calculated.

The input space vector is averaged by u = t_a*u_a + t_b*u_b + t₀*0, where u_a is the space vector at the left border of the sector and u_b is the space vector at the right border of the sector. If necessary, a zero length vector is applied additionally.

The relative time spans for averaging over one switching period are determined by the following equations:

• Real part: u*cos(φ) = u_b*t_b*cos(60°) + u_a*t_a*1
• Imag.part: u*sin(φ) = u_b*t_b*sin(60°)
• t_a + t_b + t₀ = 1

To obtain the positive fire signal, the switching time spans are distributed symmetrically: t₀/4 + t_a/2 + t_b/2 +t₀/2 + t_b/2 + t_a/2 + t₀/4

The switching pattern of the negative fire signal is just the inverse of the positive fire signal.