Converters

This section provided a general description of converters in Schematic Editor, including converter control options, thermal model, variable delay, and the Measurements tab.

In the Typhoon toolchain, converter switches are modeled as ideal switches with zero on resistance, infinite off resistance, and instantaneous switching transition. In addition, all the converter switching blocks (i.e. two-level three-phase IGBT inverter, six-pulse diode rectifier etc.) are modeled as closed black-boxes that can only be used in the schematic diagram as is. Currently, is not possible for a user to construct new switching converters using individual switches. Each power electronics converter has its own weight, as shown in Table 1. The weight of a converter defines how many blocks can be run by a single processing core (SPC). Each SPC has processing capability for power electronics switching blocks weighing 3 or 4, depending on the used device and configuration.

Table 1. Weight definition for PESBs
Power electronics converter weight table
Converter description	Weight
Buck converter	1
Boost converter	1
Flyback converter	1
Antiparallel thyristor leg	1
AC Switch	1
Three phase antiparallel thyristors	3
Single phase diode rectifier	1
Two diode full wave rectifier	1
Single phase thyristor rectifier	2
Diode leg	1
IGBT Leg	1
T Type Leg	1
NPC Leg	1
Single phase inverter	1
Single phase H6 inverter	2
Single phase H6.5 inverter	2
Three phase diode rectifier	3
Three phase thyristor rectifier	3
Three phase two level inverter	3
Three phase two level current source inverter	2
Three phase three level NPC inverter	3
Three phase three level T-type inverter	3
Three phase three level capacitor clamped inverter	3
Three phase three level ANPC inverter	3
Three phase four level inverter	3
Three phase asymmetric inverter	3
Three level flying capacitor leg	1
Four level flying capacitor leg	1
Five level flying capacitor leg	2
Seven level flying capacitor leg	3
Nine level flying capacitor leg	4
ANPC flying capacitor inverter 7 level leg	2
ANPC flying capacitor inverter 9 level leg	3
MMC Leg - Switching Function	/
Active full wave rectifier	1
HERIC converter	2
Three Phase Two-Level Current-Source Cycloconverter	2
Quadratic Boost - R2P2	1
Ćuk	1
SEPIC	1
Symmetrical boost	1
Vienna rectifier	3
XY Converter	2
Zeta Converter	1 or 2
Forward Converter	1
Buck - Boost Converter	1
Push - Pull Converter	1

For example, a buck converter weighs 1 and a single-phase inverter weighs 2, so these two PESBs can fit together in one SPC. Three buck converters can also fit into one SPC. A three-phase inverter weighs 3, so an additional converter cannot fit into the same SPC as this inverter. Just as a reminder, circuits are split into separate processing cores using some of the available coupling components.

Converter control options

There are several options for how controllable converters (such as inverters and thyristor-based components) can be controlled:

Digital inputs (per switch or per phase leg) - per switch is supported by all controllable converters
Internal modulator (internal FPGA-based modulator) - supported by a subset of converters
Model (direct switch control from the signal processing model) - supported by all controllable converters

Switching between control options is done through the Control property, which can be selected in the General tab of the Component Properties menu. Its value can be selected from the combo (dropdown) box. If a component is only controlled by Digital inputs, the Control property does not exist.

Digital inputs control options are supported by all controllable converters by default. Gate drive signal (GDS) sampling time (for example: the PWM gate drive signal) is higher than the simulation time step, typically 20ns.

The Internal modulator control option allows signal inputs to appear within the converter. This enables use of the internal PWM modulator for controlling the model. It is supported by the following converters:

IGBT leg
Buck converter
Boost converter
Flyback converter
Ćuk converter
Single phase two level converter (H-bridge)
Three phase two level converter
Three phase three level NPC converter
Active Full Wave Rectifier
Quadratic Boost - R2P2
SEPIC converter
XY converter
Zeta converter
Forward converter,
Buck - Boost converter,
Push - Pull converter.

There is one Enable input and 1 to 3 reference signal inputs depending on the number of PWM channels used. For example, the IGBT leg uses one PWM channel which requires only one reference input. The three-phase inverter requires three PWM channels and 3 corresponding reference inputs. Figure 1 shows the PWM modulator inputs for the IGBT leg and three-phase two-level converter.

The Model control option is available for all controllable converters. If the control option is set to Model, an additional signal input will appear: the input vector for the gate drive signals. The length of the input vector is equal to the number of controllable switches in the converter. An example is shown in figure below.

PWM enabling

PWM signals are activated by checking the PWM enabling checkbox.

The Sen parameter selects the digital input pin to supply the external PWM-enabling signal. When the signal is active, PWM signals are enabled and control their corresponding switches. The Sen_logic parameter selects either active high (High-level on the digital input turns on the PWM signals) or active low (Low-level on the digital input turns on the PWM signals) digital logic.

Switching delay

The Switching Delay - Timing feature models turn on and off delays for IGBTs (delay from active gate signal transition to the start of conducting and vice versa). The Turn Off Switching Delay option is defined as a function of the output current at the moment of switching, while the Turn On Delay option is constant. The maximum value of the delay is limited to 10µs.

Since the Switching Delay block is placed before the DTV (Dead Time Violation) logic, it can also be used to detect the minimum dead time period duration. In that case, Turn On Delay should be set to zero and Turn Off Delay should be set to the minimum dead time duration value.

The switching delay is activated by checking the Enable delays checkbox. Fixed and variable delays can be defined. A variable delay can be defined in a comma-separated form, as shown in Figure 5.

Note: The Switching Delay function is not supported when using Virtual HIL.

Note: The Variable Switching Delay feature is currently implemented in the IGBT leg, NPC leg, NPC T Type leg, Three Level Flying Capacitor Inverter Leg and their corresponding three-phase components.

Measurements tab

It is possible to measure currents of the switches of a power electronics switching block. The specific currents to be measured can be chosen by checking the box next to their name. The Measurement tab is shown in Figure 6.

Checked measurement will appear in the list of output variables as I_(name)_(switch name). For example, if the converter name is 3phINV and the current measurement of Phase A Bottom Switch is checked, an analog signal named I_3phINV_Sa_bot will appear in analog output variables list.

Note: Switch current measurements are currently available only for three phase inverters.

Digital Alias

If a converter is controlled by digital inputs, an alias for every digital input used by the converter will be created. Digital input aliases will be available under the Digital inputs list alongside existing Digital input signals. The alias will be shown as Converter_name.Switch_name, where Converter_name is name of the converter component and Switch_name is name of the controllable switch in the converter.

The current version of Schematic Editor offers a selection of the following types of converter components:

Symmetrical Boost converter

Flyback converter

Antiparallel thyristor leg

AC Switch