Introduction

This block sets all the relevant parameters of Modular Multilevel Converter (MMC) CPU model which can be adjusted during real-time simulation. Cell capacitance, discharge resistance, gating signals dead-time, cell capacitor mode are some parameters that can be adjusted during simulation. In addition, users can switch between two valve modeling modes: 1) detailed MMC valve mode, and 2) valve equivalent with average value model (AVM). In detailed MMC valve mode, the detailed switching phenomenon and individual cell voltages are modeled, whereas in AVM the submodules capacitors are replaced with a valve equivalent capacitor which can further improve computation efficiency.

Mask and Parameters

Common

Name	Description	Unit	Variable = {Possible Values}
Select model type	This option is selected for the model operating in different modes: 0: AVM (Valve equivalent average value model) 1: CPU model (Switching function-based detailed model)		{0, 1}
Cell capacitor [Farads]	Capacitance of each cell capacitor in Farad	Farad	>0
Discharge Resistance of cell capacitor [ohms]	Discharging resistance in ohms	Ohm	>0
Vcap mode	This option is selected for different operation modes of the capacitors: 0: normal operation: the capacitors are under normal operation where they obey physical law to be charged or discharged. 1: Vcap reset to 0: the capacitor voltage is forcedly set to zero 2: Vcap apply average value:(Not supported presently) 3: Vcap set to a fixed value: the capacitors voltages can be set to a user-defined value		{0,1,2,3}
Vcap fix value (SI)	The fixed value set when Vcap is in mode 3, i.e., Vcap set to a fixed value.	Volt	>=0
Enable pulse	Enables the gating signals.
G5 ON (check)/OFF (unchecked)	For all clamp double submodules, enables gating signal of S5 switch, i.e., G5

CPU

Name	Description	Unit	Variable = {Possible Values}
SM type	Specify the submodule (SM) or cell type of the converter Half Bridge SM Full Bridge SM Clamp Double SM T-type SM
number of SM (nb must match parameter set in SM block)	Specify the total number of SMs per valve (for Clamp Double SM, the number of SM should be equal to the number of capacitor)		maximum value is 50
VBC mode	Voltage Balance Control (VBC) mode: mode 1: only switch 1 SM with maximum or minimum capacitor voltage at each step if the reference number of ON SM is different than the actual value. mode 2: SMs are ON or OFF according to sorting results of SM capacitor voltages.
VBC error (only for mode 1)	In mode 1, if the reference number of ON SM is same as the actual value and the SM with maximum or minimum capacitor voltage has its voltage difference from the nominal voltage more than the VBC error, the SM is switched.	pu	[0,1)
PWM (unchecked) or NLC (checked)	If unchecked, gating signals are generated by pulse width modulation (PWM) method; and if checked, gating signals are generated by nearest level control (NLC) method.
Keep cell short-circuit upon error	If checked, if a short circuit happens to an SM its capacitor is considered to be damaged and its voltage id kept at 0.
IGBT deadtime (pu of Ts, [0,1))	Deadtime of IGBT pairs. For example, for 25 μs simulation time-step and 5 μs deadtime, the value will be 5/25 =0.2.	pu	[0,1)

AVM

Name	Description		Unit	Variable = {Possible Values}
Number of HBSM	Number of half-bridge SM (cell)
Number of FBSM	Number of full-bridge SM (cell)
Number of CDSM	Number of Clamp double SM (cell)

Inputs, Outputs and Signals Available for Monitoring

Inputs

There is no input for this block.

Outputs

Name	Description
MMCPara	Configuration signals sent to MMC CPU block and VBC subsystem.

Description

Limitations

For this block, the maximum number of submodules that can be set for each valve is 50.

MMC User Documentation

MMC CPU Parameters Block