Buck-Boost Converter

DC-DC is an inverting converter, or a step-up/step-down voltage regulator controlled by a controller.

blockType: AcausalElectricPowerSystems.Converters.BuckBoost

Path in the library:

/Physical Modeling/Electrical/Semiconductors & Converters/Converters/Buck-Boost Converter

Description

Block Buck-Boost Converter It is a DC-DC converter that can either raise or lower the DC voltage from one side of the converter to the other, depending on the connected controller and control signal generator. Converters of this type are also known as step-up/step-down voltage regulators because they can increase or decrease the voltage value.

The unit can also invert the voltage by changing the polarity of the output voltage to the opposite of the input voltage. The value of the output voltage depends on the fill factor.

Block Buck-Boost Converter allows you to simulate an inverting combined converter with a single switching device. 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 before 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 before 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-Boost Converter It can be modeled as an inverting combined converter with a directional gate control port for the signal.

Inverting converter models contain a switching device, a diode, an inductor, and an output capacitor. buck boost converter 1 The capacitor smooths the output voltage.

Protection

A damping circuit can be activated 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

Inverting converter model with directional control port option (PS):
- Create a directional control signal, for example, from basic mathematical blocks, and connect it to the G port.
The model of the inverting 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.

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-Boost 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) a value 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 piecewise constant approximation mode by dividing the initial mode by to normalize it back to the range [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

Input

# G — shutter contact (output)
scalar

Details

The control signal port connected to the switch gate.

Dependencies

To use this port, set the parameter Gate-control port meaning PS.

Data types	`Float64`
Complex numbers support	No

Parameters

Switching Device

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

Details

Directional or electric switch gate control port.

Values	`Signal` \| `Electrical`
Default value	`Signal`
Program usage name	`gate_control_port`
Evaluatable	No

Details

The type of switching device for the converter.

Values	`GTO` \| `Ideal Semiconductor Switch` \| `IGBT` \| `MOSFET` \| `Thyristor` \| `Averaged Switch`
Default value	`Ideal Semiconductor Switch`
Program usage name	`switching_device_type`
Evaluatable	No

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

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

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

Details

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

# Threshold voltage — Threshold voltage
V | uV | 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` \| `uV` \| `mV` \| `kV` \| `MV`
Default value	`6.0 V`
Program usage name	`V_threshold`
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.
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.

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.

Values	`Diode with no dynamics` \| `Diode with charge dynamics`
Default value	`Diode with no dynamics`
Program usage name	`protection_diode_parameterization`
Evaluatable	No

# Forward voltage — direct current voltage
V | uV | 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` \| `uV` \| `mV` \| `kV` \| `MV`
Default value	`0.8 V`
Program usage name	`V_f_diode`
Evaluatable	Yes

# On resistance — switching resistance
Ohm | mOhm | kOhm | MOhm | GOhm

Details

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

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

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

Details

The conductivity of a reverse-biased diode.

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

LC Parameters

# Inductance — inductance
H | nH | uH | mH

Details

The inductance.

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

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

Details

The series resistance of the inductor.

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

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

Details

Container.

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

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

Details

The series resistance of the capacitor.

Units	`Ohm` \| `mOhm` \| `kOhm` \| `MOhm` \| `GOhm`
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	No