Description

The MMC-2P cell block implements a bipolar bridge with a capacitor. Series RC snubber circuits are connected in parallel with each switch device. Press Help for suggested snubber values when the model is discretized. The gates are controlled by Double signals. The following figure presents the equivalent electrical circuit of the MMC cell block implement a unipolar bridge.

Figure 72: Equivalent Electrical Circuit of the MMC-2P cell Block

The voltage between A and B is determined by the switching applied to g1 to g4. g1 and g2 must be complementary and so does g3 and g4.

The RC snubber in shunt with the switch is required to solve numerical oscillation. Using the time step and the equivalent inductance of the circuit the value of the Rsnubber and Csnubber are given by the following equation.

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Where nbcells is the number of cells in series and Leq is the equivalent inductance

Table of Contents

Mask and Parameters

Snubber resistance	Snubber resistance value, only used in high impedance mode.
Snubber Capacitor	Snubber capacitor value, only used in high impedance mode.
Cell capacitor	Value of the cell's capacitor.
Ron	Internal resistance of the selected device, in ohms.
Number of cells	This determines how many cells are connected in series. A maximum of 20 cells can be connected in series. If more then 20 cells are required, a second MMC_2P block needs to be connected in series.
Sample time	Time at which the capacitor voltage will be computed.

Inputs and Outputs

Inputs

g1 (double)	double signals that control the upper left switch gates. This signal has to be a vector of the same length as the number of cells. A signal value of 1 indicates the switch is conducting, while a value of zero indicates the switch is OFF.
g2 (double)	double signals that control the lower left switch gates. This signal has to be a vector of the same length as the number of cells. A signal value of 1 indicates the switch is conducting, while a value of zero indicates the switch is OFF.
g3 (double)	double signals that control the upper right switch gates. This signal has to be a vector of the same length as the number of cells. A signal value of 1 indicates the switch is conducting, while a value of zero indicates the switch is OFF.
g4 (double)	double signals that control the lower right switch gates. This signal has to be a vector of the same length as the number of cells. A signal value of 1 indicates the switch is conducting, while a value of zero indicates the switch is OFF.
Center (SPS)	Middle left point of the cell.
Common (SPS)	Middle right point of the cell.

Outputs

Vc (double)	The voltage at the cell's capacitor, a vector of the same length as the number of cells.

Characteristics

Direct Feedthrough	No
Sample Time	Parameter
Work Offline	Yes
Dimensionalized	Yes