The 2-level converter (Switching Function) can be used in applications such as the integration of renewable energy sources and motor drives. It models a three-phase power converter of the VSC (Voltage Source Converter) type. This converter is modeled using a switching function suitable for real-time simulation. The switching function presents a good compromise between the real-time performance of an average model and the accuracy of using detailed switches.

NOTE: In order to obtain accurate results, the options Activate iterative method and Solve control inputs before solving power in Simulation Settings must be selected when using this component.

Mask and Parameters

Parameter Name	Description	Unit	Variable = {Possible Values}
Description	Use this field to add all kinds of information about the component		Description = {'string'}
Diode on-state resistance	Internal resistance of diodes	Ohm	Rclose = { [1e-12, 1e12] }
Diode snubber resistance	Snubber resistance of the diodes	Ohm	Rsnubber = { [1e-12, 1e12] }

Ports, Inputs, Outputs and Signals Available for Monitoring

Ports

Name	Description
net_1	Network connector on the AC side (supports only 3-phase connections)
DCplus	Network connector on the DC side. The + sign indicates this is the positive end (supports only 1-phase connections)
DCminus	Network connector on the DC side. The - sign indicates this is the negative end (supports only 1-phase connections)

Inputs

Name	Description
P	Vectorized signal containing six firing pulses to control the converter.

Outputs

Name	Description
V	Vectorized voltage signal containing the phase-ground voltage of the AC side (Va, Vb and Vc) and the DC link (Vdc).
I	Vectorized current signal containing the phase-ground current of the AC side (Ia, Ib and Ic) and the current of the DC link (Idc).

Sensors

Name	Description	Unit
P[P1]	Gating signal controlling Q1.
P[P2]	Gating signal controlling Q2.
P[P3]	Gating signal controlling Q3.
P[P4]	Gating signal controlling Q4.
P[P5]	Gating signal controlling Q5.
P[P6]	Gating signal controlling Q6.
V[Va]	Voltage signal of phase A from the AC side of the converter.	V
V[Vb]	Voltage signal of phase B from the AC side of the converter.
V[Vc]	Voltage signal of phase C from the AC side of the converter.
V[Vdc]	Voltage signal from the DC link of the converter.
I[Ia]	Current signal of phase A from the AC side.	A
I[Ib]	Current signal of phase B from the AC side.
I[Ic]	Current signal of phase C from the AC side.
I[Idc]	Current signal of DC link.

Additional Information

The converter is modeled by a switching function model. The switches are replaced by two voltage sources and two diodes per phase on the AC side and a current source on the DC side.

The figure below shows the internal circuit of the converter that can be accessed by opening the subcircuit. Although the topology of the converter is similar to that of the Full-bridge converter (Switching Function), the equations for controlling the amplitude of voltage and current sources are different.

The converter is controlled by firing pulses produced by a PMW generator or by firing pulses averaged over a time step of the simulation (1/Ts), providing signals between 0 and 1 (see PWM Average Generator for 2-Level Converter (Switching Function)). Both operating modes accurately produce harmonics. In addition, this converter model correctly simulates the operation as a rectifier as well as the blanking time.

The PWM average generator outputs a vectorized gating signal to control the converter. The gating signal contains six firing pulses. The first two pulses control the Q1 and Q2 switching devices (phase A of the converter), pulses three and four control the Q3 and Q4 switching devices (phase B of the converter), and the last two pulses control the Q5 and Q6 switching devices (phase C of the converter).

Limitations

This model must be used with the PWM Average Generator for 2-Level Converter (Switching Function) component available in the Control Sources library of HYPERSIM or with an input FPGA module (contact our technical support for an example).

This model does not participate in the load flow solution.

References

MathWorks, Two-Level Converter Mathworks.com. https://www.mathworks.com/help/physmod/sps/powersys/ref/twolevelconverter.html

M. H. Rashid, Power electronics handbook, 4^th ed. Butterworth-Heinemann, 2017

HYPERSIM Documentation

2-Level Converter (Switching Function)