Full-Bridge MMC (External DC Links)

(To be removed) Full-bridge MMC power converter with external DC connections

The Specialized Power Systems library will be removed in R2026a. Use the Simscape™ Electrical™ blocks and functions instead. For more information on updating your models, see Upgrade Specialized Power System Models to use Simscape Electrical Blocks.

Libraries:
Simscape / Electrical / Specialized Power Systems / Power Electronics

Description

The Full-Bridge MMC (External DC Links) block implements a full-bridge modular multilevel converter with external DC links. The converter consists of multiple series-connected power modules. Each power module consists of one H-Bridge with external DC outputs.

You can choose from three model types:

Switching devices — The converter uses IGBT/diode pairs.
Switching function — The converter is based on a switching-function model.
Average model (Uref-controlled) — The converter is modeled using a switching-function model directly controlled by the reference voltage signals.

Ports

Input

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g — Firing pulse gate
vector

Gate signal that controls the converter. The gate signal contains the firing pulses to control four switches at each power module in the converter (four times the Number of power modules pulses).

Dependencies

This port is visible only when you set the Model type parameter to Switching devices or Switching function.

Data Types: single | double | Boolean

Uref — Reference
vector

Reference voltage signal that controls the converter. The vectorized signal contains one reference voltage for each power module in the converter.

Dependencies

This port is visible only when you set the Model type parameter to Average model (Uref-controlled).

Data Types: single | double

BL — Firing pulse block
scalar

Input used to block all firing pulses when the signal is 1. To block all firing pulses to the converter, input a value of 1.

Data Types: single | double | Boolean

Output

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c1+ — Positive DC terminal
scalar

Positive DC terminal of the first power module. Additional positive DC terminals, labeled c2+, c3+, c4+, and so on, are added to the block for the corresponding number of power modules defined by the Number of power modules parameter.

c1- — Negative DC terminal
scalar

Negative DC terminal of the first power module. Additional negative DC terminals, labeled c2-, c3-, c4-, and so on, are added to the block for the corresponding number of power modules defined by the Number of power modulesparameter.

1 — Output terminal
vector

Output terminal 1 of the converter.

2 — Output terminal
vector

Output terminal 2 of the converter.

Parameters

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Model type — Converter model
`Switching devices` | `Switching function` | `Average model (Uref-controlled)`

Specify the model type to use for the switching devices. You can choose from three model types:

Switching devices — The converter uses IGBT/diode pairs. A multilevel PWM generator produces firing pulses (0/1 signals), which trigger switching in the converter.
Switching function — The converter is based on a switching-function model. The model uses two voltage sources and two diodes on the AC side, and two current sources on the DC side.
The converter is controlled by firing pulses produced by a PWM generator (0/1 signals) or by firing pulses averaged over a specified period (PWM averaging: signals from 0 through 1). Both modes of operation produce harmonics normally generated by a PWM-controlled converter, and also correctly simulate the rectifying operation and blanking time. This model type is suitable for real-time simulation
Average model (Uref-controlled) — The converter is modeled using a switching-function model directly controlled by the reference voltage signals. A PWM generator is not required. This model provides the fastest simulations.

Dependencies

Each Model type option enables a particular set of parameters.

Number of power modules — Number of modules
`1` (default)

Number of series-connected power modules that are in the converter.

Device on-state resistance (Ohms) — Resistance
`1e-3` (default)

Internal resistance of the switching devices.

Dependencies

This parameter is enabled when the Model type parameter is set to Switching devices.

Snubber resistance (Ohms) — Resistance
`1e6` (default) | inf

To eliminate the snubbers, set the snubber resistance to inf.

Dependencies

This parameter is enabled when the Model type parameter is set to Switching devices.

Snubber capacitance (F) — Capacitance
`inf` (default)

Snubber resistance of the switching device. To eliminate the snubbers, set the snubber capacitance to 0.

Dependencies

This parameter is enabled when the Model type parameter is set to Switching devices.