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Two-Quadrant DC/DC Converter

Implement two-quadrant DC/DC power converter

Library

Simscape / Electrical / Specialized Power Systems / Power Electronics

  • Two-Quadrant DC/DC Converter block

Description

The Two-Quadrant DC/DC Converter block implements a two-quadrant DC/DC power converter. You can choose from four model types :

  • Switching devices — The converter is modeled with IGBT/diode pairs controlled by firing pulses produced by a PWM generator. This model provides the most accurate simulation results.

  • Switching function — The converter is modeled by a switching-function model. The switches are replaced with two voltage sources and two diodes on the AC side and with two current sources on the DC side.

    The converter is controlled by firing pulses produced by a PWM generator (0/1 signals) or by firing pulses averaged over a specified period (PWM averaging: signals between 0 and 1). Both modes of operation produce harmonics normally generated by a PWM-controlled converter and also correctly simulate rectifying operation as well as blanking time. This model type is well-suited for real-time simulation.

  • Average model (D-controlled) — The converter is modeled using a switching-function model directly controlled by the duty cycle signal (0 < D < 1). A PWM generator is not required.

  • Average model (D-controlled, no rectifier mode) — The block uses the voltage source directly controlled by the reference voltage to model the converter. The model does not require a PWM generator and does not simulate the rectifier mode. This setting provides the fastest simulations.

    When doing real-time simulation, use the Switching function setting with the firing pulses averaged, or the Average model (D-controlled) or Average model (D-controlled, no rectifier mode) settings.

Parameters

Model type

Specify the model type to use:

  • Switching devices (default)

  • Switching function

  • Average model (D-controlled)

  • Average model (D-controlled, no rectifier mode)

Device on-state resistance (Ohms)

Internal resistance of the switching devices, in ohms. This parameter is available only when you set the Model type parameter to Switching devices. The default value is 1e-3.

Snubber resistance (Ohms)

The snubber resistance, in ohms. Set the snubber resistance to inf to eliminate the snubbers. This parameter is available only when you set the Model type parameter to Switching devices. The default value is 1e6.

Snubber capacitance (F)

The snubber capacitance, in farads. Set the snubber capacitance to 0 to eliminate the snubbers. This parameter is available only when you set the Model type parameter to Switching devices. The default value is inf.

Diode on-state resistance (Ohms)

Internal resistance of the diodes, in ohms. This parameter is available only when you set the Model type parameter to Switching function or Average model (D-controlled). The default value is 1e-3.

Diode snubber resistance (Ohms)

The snubber resistance, in ohms. Set the snubber resistance to inf to eliminate the snubbers. This parameter is available only when you set the Model type parameter to Switching function or Average model (D-controlled). The default value is 1e6.

Diode snubber capacitance (F)

The snubber capacitance in farads. Set the snubber capacitance to 0 to eliminate the snubbers. This parameter is available only when you set the Model type parameter to Switching function or Average model (D-controlled). The default value is inf.

Diode forward voltage (V)

Forward voltage, in volts, across the diode when it is conducting. This parameter is available only when you set the Model type parameter to Switching function or Average model (D-controlled). The default value is 1e-3.

Current source snubber resistance (Ohms)

The snubber resistance in ohms across the two current sources. Set the snubber resistance to inf to eliminate the snubbers. This parameter is available only when you set the Model type parameter to Switching function or Average model (D-controlled). The default value is inf.

Inputs and Outputs

g

A vectorized gating signal to control the converter. The gating signal contains two firing pulses. The first pulse controls Q1 and the second pulse controls Q2. This port is visible only when you set the Model type parameter to Switching devices or Switching function.

D

The duty cycle signal is a value between 0 and 1 used to control the converter. This port is visible only when you set the Model type parameter to Average model (D-controlled).

BL

You can block all firing pulses to the converter by applying a signal value of 1 at the BL input.

Examples

See the Power Converters Modeling Techniques example for a comparison of the three converter modeling techniques.

Version History

Introduced in R2015b