Modelica.Electrical.PowerConverters.DCAC.Control

Control components for DC to AC converters

Information

Currently there are only three-phase PWM implemented (not polyphase).

Extends from Modelica.Icons.Package (Icon for standard packages).

Package Content

Name	Description
PWM	PulseWidthModulation
SVPWM	SpaceVector Pulse Width Modulation
IntersectivePWM	Intersective PWM

Modelica.Electrical.PowerConverters.DCAC.Control.PWM

PulseWidthModulation

Information

Let the user choose the PWM type from:

• Space Vector pulse width modulation
• Intersective pulse width modulation

Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).

Parameters

Connectors

Modelica.Electrical.PowerConverters.DCAC.Control.SVPWM

SpaceVector Pulse Width Modulation

Information

For a three-phase 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.

Extends from Modelica.Blocks.Interfaces.DiscreteBlock (Base class of discrete control blocks).

Parameters

Connectors

Modelica.Electrical.PowerConverters.DCAC.Control.IntersectivePWM

Intersective PWM

Information

The intersective PWM transforms the input space phasor u to the three-phase voltages, and compares them with the reference signals. As long as the phase voltage is greater than the corresponding reference signal, the corresponding fire signal is true. The switching pattern of the negative fire signal is just the inverse of the positive fire signal.

The user can choose from 4 different reference signals:

• Sawtooth1: sawtooth signal, same phase in all three phases
• Sawtooth3: sawtooth signal, phase shift between the three phases = period/3
• Triangle1: triangle signal, same phase in all three phases
• Triangle3: triangle signal, phase shift between the three phases = period/3

Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).

Parameters

Connectors