The TSB-RD 3-level Flying Capacitor model implements, as the name says, a 3-level flying capacitor inverter with dead-time support.
This inverter model is part of a new generation of Time-Stamped Bridge (TSB) called TSB-RD, RD standing for Real Diodes. These TSB supports interpolation methods of the previous generation of TSB. The high-impedance mode and rectifying mode are now implemented with a real SPS diode or a combination of SPS switch and thyristors (which are enablable diode in fact). Compared with the previous generation of TSB which implemented high-impedance mode with a zero-current feedback loop, TSB-RD is generally more stable and works with RC snubber of high impedance than the previous generation of TSB.
Like the previous generation of TSB, TSB-RD blocks supports dead-time smaller than simulation time step (as opposed to SPS inverter models).
TSB-RD recommended usage with SSN
The TSB-RD are built using real SPS switches, diode and/or thyristor. All 3-phase inverters have 3 internal SPS switches per leg and 9 switches for a 3-phase inverter therefore, which is close to the typical limit for pre-calculation methods in real-time systems. The TSB-RD inverters are therefore best used in conjunction with SSN and put each inverter in a unique SSN group.
Three-phase 3-level Flying Capacitor circuit inverter configuration
Switch resistance (Ohms): the internal switch (main IGBT/GTO/MOSFET and anti-parallel diode) conduction resistance in Ohms.
Snubber resistance (ohms): the snubber resistance in ohms.
Snubber Capacitance (F): the snubber capacitance in Farads.
Note: the snubbers are always ‘in circuit’ as they are modeled by SPS components, unlike the previous generation of TSB where snubber was in-circuit only during high-impedance mode.
Flying Capacitance (F): the inverter flying capacitance in Farads.
Flying Capacitance initial voltage (V): the inverter flying capacitance initial voltage in Volts.
Sample Time (s): the block sample time in seconds. Used to integrate the flying capacitor voltage.
Input and Output signals
Simulink connection points
g: the IGBT/GTO/MOSFET gate input signals. The order of the gate signal for phase A is indicated in Figure 1. Phase B and C are following. The gate signals are Mean-Active-Duty (MAD) type with a value between 0 and 1 inclusively.
Example: a transition sequence of [ 1, 0.3, 0] means [gate ON, gate turned-on at 30% of the time-step, gate OFF])
Example: a transition sequence of [ 0, 0.3, 1] means [gate OFF, gate turned-on at 70% of the time-step, gate ON]), i.e. the MAD value depends on the transition type and is equal to the average ON time of the gate signal during the time step.
Iabc: the inverter output currents in Ampere.
Vcap: the flying capacitor voltages.
Physical Modeling connection points
A,B,C: inverter outputs for phases A,B and C.
V+, Vn, V-: DC-bus connection points. (Vn is the neutral connection point, only used as a reference point in the model)
The demo model TSB_RD_3levelFlyCap_Drive.slx is available in the ARTEMiS path. The demo model implements a simple 3-phase inverter with the TSB-RD Flying Capacitor inverter with basic flying capacitor voltage control.
SSN TSB-RD (2-level, 3-level NPC, 3-level T-type) Help page.
C. Dufour, J. Mahseredjian , J. Bélanger, “A Combined State-Space Nodal Method for the Simulation of Power System Transients”, IEEE Transactions on Power Delivery, Vol. 26, no. 2, April 2011 (ISSN 0885-8977), pp. 928-935