Buck Converter

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The inverting converter.

blockType: AcausalElectricPowerSystems.Converters.Buck

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Description

Block Buck Converter It is a converter that lowers the DC voltage depending on the connected controller and control signal generator. Step-down converters are also known as step-down voltage regulators because they reduce the voltage amplitude.

Block Buck Converter allows you to simulate an asynchronous converter with one switching device or a synchronous converter with two switching devices. The following types of switching devices are possible:

GTO — lockable thyristor. For information about the volt-ampere characteristic (VAC) of the device, see GTO.
Ideal Semiconductor Switch — Perfect semiconductor controlled switch. For information about the device’s specifications, see Ideal Semiconductor Switch.
IGBT — An ideal insulated gate bipolar transistor for switching circuits. For information about the device’s specifications, see IGBT (Ideal, Switching).
MOSFET — perfect -channel MOSFET for switching circuits. For information about the device’s specifications, see MOSFET (Ideal, Switching).
Thyristor — a thyristor with a piecewise linear VAC. For information about the device’s specifications, see Thyristor (Piecewise Linear).
Averaged Switch — an average converter. The control signal port G takes values in the range from 0 to 1. When the value of G is 0 or 1, Averaged Switch fully open or fully closed, respectively. The key behaves similarly to the block Ideal Semiconductor Switch with an antiparallel diode. When the value of G is between 0 and 1, Averaged Switch partially open. You can average the signal using a pulse width modulation unit (PWM) for a certain period of time. This allows you to perform model subsampling and use modulation signals instead of PWM signals.

The topology of the converter

Buck Converter It can be modeled as an asynchronous converter with a directional gate control port for a physical signal, or as a synchronous converter with an electrical control port. To select the topology of the converter, set the parameter Modeling option meaning:

Nonsynchronous converter — asynchronous converter with additional directional and electrical gate control ports.
Synchronous converter — synchronous converter with multiplexed gate signals.

Models of asynchronous step-down converters contain a switching device, a diode, an inductor and an output capacitor. buck converter 1

The synchronous step-down converter model contains two switching devices, an inductor and an output capacitor. buck converter 2

In each case, the capacitor smooths the output voltage.

Protection

In the synchronous converter model, you can turn on the built-in protective diode for the S2 switching device. The built-in diode protects the semiconductor device by providing a conductive path for reverse current. An inductive load can cause a high reverse voltage surge when a semiconductor device suddenly cuts off the voltage supply to the load.

To enable and configure the internal protective diode block, use the parameter group Diode. This table shows how to configure the parameter. Model dynamics depending on your goals.

Goals Value for selection Built-in protective diode

Goals	Value for selection	Built-in protective diode
Do not turn on the protection	`None`	No
Turn on the protection	Give priority to simulation speed.	`Diode with no dynamics`	Block Diode
The priority of the accuracy of the model is to accurately indicate the charge dynamics in the reverse mode.	`Diode with charge dynamics`	Dynamic block model Diode

Do not turn on the protection

None

Turn on the protection

Give priority to simulation speed.

Diode with no dynamics

Block Diode

The priority of the accuracy of the model is to accurately indicate the charge dynamics in the reverse mode.

Diode with charge dynamics

Dynamic block model Diode

You can also include a damping circuit for each switching device. The damping circuits contain a resistor and a capacitor connected in series. They protect switching devices from high voltages that occur when the inductive load is powered off. Damping circuits also prevent excessive current changes when switching on the switching device.

To enable and configure the damper circuit for each switching device, use the parameter group Snubbers.

Connecting signals to the gate control port

Asynchronous converter model (Nonsynchronous converter) with directional control port option (PS):
- Create a directional control signal, for example, from basic mathematical blocks, and connect it to the G port.
Asynchronous converter model (Nonsynchronous converter) with the option of an electric control port (Electrical):
- Connect a positive DC signal to the G+ port.
- Connect the negative DC voltage signal to the G- port.
Synchronous converter model (Synchronous converter):
- Multiplex the converted gate control signals into a single vector using the block Two-Pulse Gate Multiplexer.
- Connect the vector signal to the G port.

Piecewise constant approximation in an averaged commutator

If set for the parameter Switching device meaning Averaged Switch and use the partitioning solver, block, to create the model. Buck Converter creates nonlinear splits because the equations of the averaged mode include modes , which are functions of the input signal G. To activate the piecewise constant approximation, set the parameter Integer for piecewise constant approximation of gate input (0 for disabled) the value is greater than `0'. Then this block will consider the mode as a piecewise constant integer with a fixed range. This transforms previously non-linear partitions into linear, time-varying ones.

An integer value in the range [0,K], where — parameter value Integer for piecewise constant approximation of gate input (0 for disabled), is now associated with each mode of the real value in the range [0,1]. The block calculates the mode of piecewise constant approximation by dividing the initial mode by to normalize it back to the range of [0,1]:

Assumptions and limitations

Only an average PWM-controlled pulse converter registers both continuous conduction mode (CCM) and intermittent conduction mode (DCM). An average duty cycle-controlled pulse converter captures only CCM.

Ports

Conserving

# 2+ — positive output terminal
electricity

Details

An electrical port connected to the positive terminal 2 of the DC voltage.

Program usage name

p2

# 2– — negative output terminal
electricity

Details

An electrical port connected to the negative terminal 2 of the DC voltage.

Program usage name

n2

# 1+ — positive input terminal
electricity

Details

The electrical port connected to the positive terminal 1 of the DC voltage.

Program usage name

p1

# 1– — negative input terminal
electricity

Details

The electrical port connected to the negative terminal 1 of the DC voltage.

Program usage name

n1

# G+ — the positive terminal of the switching device
electricity

Details

The electrical port connected to the positive gate terminal of the switching device.

Dependencies

To use this port, set the parameter Modeling option meaning Nonsynchronous converter and for the parameter Gate-control port meaning Electrical.

Program usage name

gate_p

# G– — the negative terminal of the switching device
electricity

Details

The electrical port connected to the negative gate terminal of the switching device.

Dependencies

To use this port, set the parameter Modeling option meaning Nonsynchronous converter and for the parameter Gate-control port meaning Electrical.

Program usage name

gate_n

# G — shutter contact
electricity

Details

The electrical port connected to the gate contact of the switch.

Dependencies

To use this port, set the parameter Modeling option meaning Synchronous converter.

Program usage name

gate_port

Input

# G — shutter contact (output)
scalar

Details

The control signal port connected to the switch gate.

Dependencies

To use this port, set the parameter Modeling option meaning Nonsynchronous converter and for the parameter Gate-control port meaning PS.

Data types	`Float64`
Complex numbers support	No

Parameters

# Modeling option — simulation of asynchronous or synchronous converter
Nonsynchronous converter | Synchronous converter

Details

Selecting the asynchronous or synchronous converter model.

Values	`Nonsynchronous converter` \| `Synchronous converter`
Default value	`Nonsynchronous converter`
Program usage name	`topology`
Evaluatable	Yes

Switching Device

# Gate-control port — defines the control port: directional or electric
PS | Electrical

Details

Directional or electric switch gate control port.

Dependencies

To use this parameter, set for the parameter Modeling option meaning Nonsynchronous converter.

Values	`PS` \| `Electrical`
Default value	`PS`
Program usage name	`gate_control_port`
Evaluatable	Yes

Details

The type of switching device for the converter. The switches are identical for the synchronous model.

Values	`GTO` \| `Ideal Semiconductor Switch` \| `IGBT` \| `MOSFET` \| `Thyristor` \| `Averaged Switch`
Default value	`Ideal Semiconductor Switch`
Program usage name	`switching_device_type`
Evaluatable	Yes

# On-state resistance — resistance in the switched-on state
Ohm | GOhm | MOhm | kOhm | mOhm

Details

The resistance between the anode and the cathode when switched on.

For different types of switching devices, the parameter On-state resistance calculated as follows:

For GTO — the rate of voltage change relative to the current is higher than the forward voltage.
For Ideal Semiconductor Switch — anode-cathode resistance when the device is switched on.
For IGBT — collector-emitter resistance when the device is switched on.
For Thyristor — anode-cathode resistance when the device is switched on.
For Averaged Switch — the resistance of the anode-cathode when the device is switched on.

Units	`Ohm` \| `GOhm` \| `MOhm` \| `kOhm` \| `mOhm`
Default value	`0.001 Ohm`
Program usage name	`R_on`
Evaluatable	Yes

# Off-state conductance — conductivity in the off state
S | mS | nS | uS | 1/Ohm

Details

The anode-cathode conductivity is switched off.

Conduction when the device is turned off. The value should be less than , where — parameter value On-state resistance.

For different types of switching devices, the resistance at rest is calculated as follows:

For GTO — anode-cathode conductivity.
For Ideal Semiconductor Switch — anode-cathode conductivity.
For IGBT — collector-emitter conductivity.
For MOSFET — drain-source conductivity.
For Thyristor — the conductivity of the anode-cathode.

Units	`S` \| `mS` \| `nS` \| `uS` \| `1/Ohm`
Default value	`1.0e-5 1/Ohm`
Program usage name	`G_off`
Evaluatable	Yes

# Threshold voltage — Threshold voltage
V | MV | kV | mV

Details

The threshold voltage for the gate-cathode circuit. The switch turns on when the gate-cathode circuit voltage exceeds this value. For different types of switching devices, the parameter Threshold voltage calculated as follows:

For Ideal Semiconductor Switch — gate-cathode voltage.
For IGBT — gate-emitter voltage.
For MOSFET — gate-source voltage.

Units	`V` \| `MV` \| `kV` \| `mV`
Default value	`6.0 V`
Program usage name	`V_threshold`
Evaluatable	Yes

# Forward voltage — direct current voltage
V | MV | kV | mV

Details

For different types of switching devices, the parameter Forward voltage calculated as follows:

For GTO — the minimum voltage required at the ports of the anode and cathode blocks so that the slope of the volt-ampere characteristic (VAC) of the device is , where — parameter value On-state resistance.
For IGBT — the minimum voltage required at the collector and emitter ports so that the slope of the VAX diode is , where — parameter value On-state resistance.
For Thyristor — the minimum voltage required to turn on the device.

Units	`V` \| `MV` \| `kV` \| `mV`
Default value	`0.8 V`
Program usage name	`V_f`
Evaluatable	Yes

# Gate trigger voltage, Vgt — Threshold voltage
V | MV | kV | mV

Details

The threshold voltage for the gate-cathode circuit. The device turns on when the gate-cathode circuit voltage exceeds this value.

Dependencies

To use this parameter, set for the parameter Switching device meaning GTO.

Units	`V` \| `MV` \| `kV` \| `mV`
Default value	`1.0 V`
Program usage name	`V_GT`
Evaluatable	Yes

# Gate turn-off voltage, Vgt_off — Threshold voltage
V | MV | kV | mV

Details

The threshold voltage for the gate-cathode circuit. The device turns off when the gate-cathode circuit voltage drops below this value.

Dependencies

To use this parameter, set for the parameter Switching device meaning GTO.

Units	`V` \| `MV` \| `kV` \| `mV`
Default value	`-1.0 V`
Program usage name	`V_GT_off`
Evaluatable	Yes

# Holding current — threshold current
A | MA | kA | mA | nA | pA | uA

Details

Threshold gate current. The device remains switched on when the current exceeds this value, even when the voltage between the gate and the cathode drops below the gate actuation voltage.

Dependencies

To use this parameter, set for the parameter Switching device meaning GTO.

Units	`A` \| `MA` \| `kA` \| `mA` \| `nA` \| `pA` \| `uA`
Default value	`1.0 A`
Program usage name	`I_H`
Evaluatable	Yes

# Drain-source on resistance — open channel resistance
Ohm | GOhm | MOhm | kOhm | mOhm

Details

The resistance between the drain and the source, which also depends on the voltage between the gate and the source.

Dependencies

To use this parameter, set for the parameter Switching device meaning MOSFET.

Units	`Ohm` \| `GOhm` \| `MOhm` \| `kOhm` \| `mOhm`
Default value	`0.001 Ohm`
Program usage name	`R_ds`
Evaluatable	Yes

# Integer for piecewise constant approximation of gate input (0 for disabled) — piecewise constant approximation

Details

An integer used to perform a piecewise constant approximation of the gate input data.

Dependencies

To use this parameter, set for the parameter Switching device meaning Averaged Switch.

Default value	`0`
Program usage name	`K`
Evaluatable	Yes

Diode

# Model dynamics — the diode model
Diode with no dynamics | Diode with charge dynamics

Details

The type of diode. The following options are possible:

Diode with no dynamics — select this option to prioritize the simulation speed using the block Diode. This option is used by default for asynchronous converter.
Diode with charge dynamics — Select this option to increase the accuracy of the model in terms of charge dynamics in reverse mode using the switching diode model of the block Diode.

If for the parameter Switching device the value is selected in the settings Averaged Switch, this parameter is not displayed, and for the parameter Model dynamics The value is set automatically Diode with no dynamics.

Dependencies

To use this parameter, set for the parameter Modeling option meaning Nonsynchronous converter.

Values	`Diode with no dynamics` \| `Diode with charge dynamics`
Default value	`Diode with no dynamics`
Program usage name	`protection_diode_parameterization_nonsynchronous`
Evaluatable	Yes

# Forward voltage — direct current voltage
V | MV | kV | mV

Details

The minimum voltage required on the anode and cathode blocks so that the slope of the VAX diode is equal to , where — parameter value On resistance.

Units	`V` \| `MV` \| `kV` \| `mV`
Default value	`0.8 V`
Program usage name	`V_f_diode`
Evaluatable	Yes

# On resistance — open transition resistance
Ohm | GOhm | MOhm | kOhm | mOhm

Details

The rate of voltage change relative to the current is higher than the voltage set by the parameter Forward voltage.

Units	`Ohm` \| `GOhm` \| `MOhm` \| `kOhm` \| `mOhm`
Default value	`0.001 Ohm`
Program usage name	`R_on_diode`
Evaluatable	Yes

# Off conductance — closed junction conductivity
S | mS | nS | uS | 1/Ohm

Details

The conductivity of a reverse-biased diode.

Units	`S` \| `mS` \| `nS` \| `uS` \| `1/Ohm`
Default value	`1.0e-5 1/Ohm`
Program usage name	`G_off_diode`
Evaluatable	Yes

# Junction capacitance — transfer capacity
F | mF | nF | pF | uF

Details

The capacity of the diode junction.

Units	`F` \| `mF` \| `nF` \| `pF` \| `uF`
Default value	`50.0 nF`
Program usage name	`C_diode`
Evaluatable	Yes

# Peak reverse current, iRM — peak reverse current during iRM measurement
A | MA | kA | mA | nA | pA | uA

Details

The maximum return current measured by the external test circuit.

Units	`A` \| `MA` \| `kA` \| `mA` \| `nA` \| `pA` \| `uA`
Default value	`-235.0 A`
Program usage name	`i_rm_diode`
Evaluatable	Yes

# Initial forward current when measuring iRM — initial forward current during iRM measurement
A | MA | kA | mA | nA | pA | uA

Details

The initial forward current when measuring the peak reverse current. This value must be greater than zero.

Units	`A` \| `MA` \| `kA` \| `mA` \| `nA` \| `pA` \| `uA`
Default value	`300.0 A`
Program usage name	`i_f_diode`
Evaluatable	Yes

# Rate of change of current when measuring iRM — the rate of change of current during iRM measurement
A/s | A/us

Details

The rate of change of the current when measuring the peak reverse current.

Units	`A/s` \| `A/us`
Default value	`-50.0 A/us`
Program usage name	`diode_current_change_rate`
Evaluatable	Yes

# Reverse recovery time parameterization — type of reverse recovery time determination
Specify stretch factor | Specify reverse recovery time directly | Specify reverse recovery charge

Details

The method for setting the reverse recovery time in the block. When choosing Specify stretch factor or Specify reverse recovery charge you can specify the value that the block will use to calculate the reverse recovery time.

Values	`Specify stretch factor` \| `Specify reverse recovery time directly` \| `Specify reverse recovery charge`
Default value	`Specify stretch factor`
Program usage name	`t_rr_diode_parameterization`
Evaluatable	Yes

# Reverse recovery time stretch factor — the stretching coefficient of the reverse recovery time

Details

The value that the block uses to calculate the parameter Reverse recovery time, trr. Specifying the stretching coefficient is an easier way to parameterize the reverse recovery time than specifying the reverse recovery charge. The higher the value of the stretching coefficient, the longer it takes for the reverse recovery current to dissipate.

Default value	`3.0`
Program usage name	`t_rr_factor_diode`
Evaluatable	Yes

# Reverse recovery time, trr — reverse recovery time
d | s | hr | ms | ns | us | min

Details

The amount of time it takes for a diode to turn off when the voltage across it reverses from forward bias to reverse.

The interval between the moment of the initial current transition through zero (when the diode turns off) and the moment the current drops to less than 10% of the peak current.

Parameter value Reverse recovery time, trr there must be more than the parameter value. Peak reverse current, iRM, divided by the parameter value Rate of change of current when measuring iRM.

Units	`d` \| `s` \| `hr` \| `ms` \| `ns` \| `us` \| `min`
Default value	`15.0 us`
Program usage name	`t_rr_diode`
Evaluatable	Yes

# Reverse recovery charge, Qrr — reverse recovery charge
C | Ah | mC | nC | uC | MAh | kAh | mAh | s*uA

Details

The value that the block uses to calculate the parameter Reverse recovery time, trr. Use this parameter if the reverse recovery charge value is specified in the block parameters as the type of reverse recovery time determination instead of the reverse recovery time value.

The reverse recovery charge is the total charge that continues to dissipate after the diode is turned off. The value must be less than , where

— the value specified for the parameter Peak reverse current, iRM;
— the value specified for the parameter Rate of change of current when measuring iRM.

Units	`C` \| `Ah` \| `mC` \| `nC` \| `uC` \| `MAh` \| `kAh` \| `mAh` \| `s*uA`
Default value	`1500.0 s*uA`
Program usage name	`Q_rr_diode`
Evaluatable	Yes

# Model dynamics — the diode model
None | Diode with no dynamics | Diode with charge dynamics

Details

The type of diode. The following options are possible:

None — this option is not available for asynchronous converter.
Diode with no dynamics — select this option to prioritize the simulation speed using the block Diode. This option is used by default for asynchronous converter.
Diode with charge dynamics — Select this option to increase the accuracy of the model in terms of charge dynamics in reverse mode using the switching diode block model. Diode.

Dependencies

To use this parameter, set for the parameter Modeling option meaning Synchronous converter.

Values	`None` \| `Diode with no dynamics` \| `Diode with charge dynamics`
Default value	`Diode with no dynamics`
Program usage name	`protection_diode_parameterization_synchronous`
Evaluatable	Yes

LC filter

# Inductance — inductance
H | mH | nH | uH

Details

The inductance of the LC filter.

Units	`H` \| `mH` \| `nH` \| `uH`
Default value	`1.0e-6 H`
Program usage name	`L_f`
Evaluatable	Yes

# Inductor series resistance — series resistance of the inductor
Ohm | GOhm | MOhm | kOhm | mOhm

Details

The series resistance of the inductor.

Units	`Ohm` \| `GOhm` \| `MOhm` \| `kOhm` \| `mOhm`
Default value	`0.0 Ohm`
Program usage name	`R_l`
Evaluatable	Yes

# Capacitance — container
F | mF | nF | pF | uF

Details

LC filter capacity.

Units	`F` \| `mF` \| `nF` \| `pF` \| `uF`
Default value	`1.0e-7 F`
Program usage name	`C_f`
Evaluatable	Yes

# Capacitor effective series resistance — capacitor resistance
Ohm | GOhm | MOhm | kOhm | mOhm

Details

The series resistance of the capacitor.

Units	`Ohm` \| `GOhm` \| `MOhm` \| `kOhm` \| `mOhm`
Default value	`1.0e-6 Ohm`
Program usage name	`R_f`
Evaluatable	Yes

Snubbers

# Snubber — activating the damper

Details

Adding a damper to the switching device.

Default value	`false (switched off)`
Program usage name	`snubber_option`
Evaluatable	Yes

# Snubber capacitance — damper capacity
F | mF | nF | pF | uF

Details

The capacity of the switching device damper.

Units	`F` \| `mF` \| `nF` \| `pF` \| `uF`
Default value	`1.0e-7 F`
Program usage name	`C_s`
Evaluatable	Yes

# Snubber resistance — damper resistance
Ohm | GOhm | MOhm | kOhm | mOhm

Details

The resistance of the switching device damper.

Units	`Ohm` \| `GOhm` \| `MOhm` \| `kOhm` \| `mOhm`
Default value	`0.1 Ohm`
Program usage name	`R_s`
Evaluatable	Yes