Synchronized 6-Pulse Generator

(To be removed) Implement synchronized pulse generator to fire thyristors of six-pulse converter

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.

Library

powerlib_extras/Control Blocks, powerlib_extras/Discrete Control Blocks

Note

The Pulse & Signal Generators section of the Control and Measurements library contains the Pulse Generator (Thyristor, 6-Pulse) block. This is an improved version of the Synchronized 6-Pulse Generator block. The new block features a mechanism that eliminates duplicate continuous and discrete versions of the same block by basing the block configuration on the simulation mode. If your legacy models contain the Synchronized 6-Pulse Generator block, they will continue to work. However, for best performance, use the Pulse Generator (Thyristor, 6-Pulse) block in your new models.

Description

The Synchronized 6-Pulse Generator block can be used to fire the six thyristors of a six-pulse converter. The output of the block is a vector of six pulses individually synchronized on the six thyristor voltages. The pulses are generated alpha degrees after the increasing zero crossings of the thyristor commutation voltages.

The figures below display the synchronization of the six pulses for an alpha angle of 0 degrees. The pulses are generated exactly at the zero crossings of the three line-to-line synchronization voltages.

The Synchronized 6-Pulse Generator block can be configured to work in double-pulsing mode. In this mode two pulses are sent to each thyristor: a first pulse when the alpha angle is reached, then a second pulse 60 degrees later, when the next thyristor is fired.

The figures below display the synchronization of the six pulses for an alpha angle of 30 degrees and with double-pulsing mode. Notice that the pulses are generated 30 degrees after the zero crossings of the line-to-line.

The pulse ordering at the output of the block corresponds to the natural order of commutation of a three-phase thyristor bridge. When you connect the Synchronized 6-Pulse Generator block to the pulses input of the Universal Bridge block (with the thyristors as the power electronic device), the pulses are sent to the thyristors in the following order:

When you build your own three-phase thyristor bridge with single thyristor blocks, you need to connect the pulse signals of the Synchronized 6-Pulse Generator block to the gate inputs of the corresponding thyristors.

Parameters

Frequency of synchronization voltages: The frequency, in hertz, of the synchronization voltages. It usually corresponds to the frequency of the network.
Pulse width: The width of the pulses, in degrees.
Double pulsing: If selected, the generator sends to each thyristor a first pulse when the alpha angle is reached, and then a second pulse 60 degrees later when the next thyristor in the sequence is fired.

Inputs and Outputs

alpha_deg: Input 1 is the alpha firing signal, in degrees. This input can be connected to a Constant block, or it can be connected to a controller system to control the pulses of the generator.
AB, BC, CA: Inputs 2, 3, and 4 are the phase-to-phase synchronization voltages Vab, Vbc, and Vca. The synchronization voltages should be in phase with the three phase-phase voltages at the converter AC terminals. Synchronization voltages are normally derived at the primary windings of the converter transformer. If the converter is connected to the delta winding of a Wye/Delta transformer, the synchronization voltages should be the phase-to-ground voltages of the primary windings.
Freq: Available only with the discrete version of the Synchronized 6-Pulse Generator. This input should be connected to a Constant block containing the fundamental frequency, in hertz, or to a PLL tracking the frequency of the system.
block: Input 5 allows you to block the operation of the generator. The pulses are disabled when the applied signal is greater than zero.
pulses: The output contains the six pulse signals.

Version History