This component implements a switching function model of modular multilevel converter (MMC) valve with half bridge submodules (HBSMs). The MMC consists of multiple HBSMs connected in series and an arm inductor. Different from the converter that is built with detail switches (MMC Valve (HB Cells)), the switching function model is modeled with two voltage sources and two diodes on the ac side and with two current sources on the dc side.
Mask and Parameters
| Name | Description | Unit | Variable = {Possible Values} | |
|---|---|---|---|---|
| Number of submodules in valve - Narm | Number of submodules in valve | - | NbSM | |
| Open state resistance - Ropen | IGBT Resistance when the switch is open | MΩ | Ropen | |
| Closed state resistance - Rclose | IGBT Resistance when the switch is closed | Ω | Rclose | |
| Snubber resistance - Rsnub | Snubber resistance | MΩ | Rsnub | |
| Snubber capacitance - Csnub | Snubber capacitance | F | Csnub | |
| Arm resistance - Rarm | Arm resistance | Ω | Rarm | |
| Arm inductance - Larm | Arm inductance | H | Larm | |
| DC storage capacitance - C | Capacitance of the submodule | F | C | |
| Voltage source serial resistance - Rsrc | Resistance connected in series with the voltage source | Ω | Rsrc | |
Ports, Inputs, Outputs and Signals Available for Monitoring
Ports
| Name | Description |
|---|---|
| + | Positive terminal of the valve |
| _ | Negative terminal of the valve |
Inputs
| Name | Description |
|---|---|
| Discharge | Reset Capacitor voltages to 0 V |
| Nblk | Number of blocked SM |
| Non | Number of ON state SM |
Outputs
| Name | Description |
|---|---|
| Iarm | Arm current |
| Vc | Average capacitor voltage |
Sensors
| Name | Description | Unit |
|---|---|---|
| Icap | Capacitor current | A |
| Vsrc_p | Parallel voltage source (blocked SMs) | V |
| Vsrc_s | Serial voltage source (on SMs) | V |
Description
The converter is modeled with switching function that can be driven by a PWM generator with (signals 0 or 1) or by a PWM averaging value (signals between 0 and 1). With PWM averaging method, the model can be as accurate as the detail model and reduce the computation effort greatly, which could run in real-time simulation.