Flyback Converter with Snubber

Purpose

Flyback converter with leakage inductance and snubber diode

Library

Electrical / Nanostep

Description

This component implements a flyback transformer with a single output. In addition to the magnetization inductance, the transformer model contains leakage inductances on both the primary and secondary sides. To avoid excessive overvoltages when the switch is turned off, the primary side is equipped with a snubber diode. The diode can be connected to the positive input voltage rail via an RC snubber (resistor in parallel with a capacitor). It is assumed that the snubber capacitance is large enough that its voltage does not change significantly during one switching cycle. The converter offers two configurations:

Sub-cycle average

The gate input is a floating-point number with values between 0 and 1 representing the relative on-time of the controlled semiconductor over one simulation step. This technique is suited for real-time simulation on a CPU or a FlexArray solver.

Nanostep / Switched

The converter is simulated with time steps in the single-digit nanosecond range. The required Nanostep solver is available exclusively on the RT Box. Both sides of the converter have current source behavior and must each be connected directly to a capacitor or a voltage source. The implementation has a weight of 3, which means it occupies an entire Nanostep solver. For offline simulation, all power semiconductors in the converter are modeled with ideal switches. The individual switches are controlled with instantaneous logical gate signals. A switch is turned on when the corresponding gate signal is true.

Parameters

Configuration

Allows you to chose between Sub-cycle average or Nanostep / Switched configuration.

Switch model (CPU code generation)

If the Configuration is set to Sub-cycle average, this parameter selects the switch model when CPU code is generated.

Semiconductor symbol

This setting lets you choose between IGBT and MOSFET for the symbol of the active semiconductor switch. It does not change the electrical behavior of the converter in simulation.

Primary leakage inductance

A non-zero scalar specifying the leakage inductance of the primary side, in henries \((\mathrm{H})\).

Primary winding resistance

A scalar specifying the resistance of the primary winding, in ohms \((\Omega)\).

Magnetizing inductance

A non-zero scalar specifying the magnetizing inductance, in henries \((\mathrm{H})\).

Turns ratio

A scalar specifying the ratio of primary-side turns to secondary-side turns.

Secondary leakage inductance

A scalar specifying the leakage inductance of the secondary side, in henries \((\mathrm{H})\).

Secondary winding resistance

A scalar specifying the resistance of the secondary winding, in ohms \((\Omega)\).

Probe Signals

Magnetizing current

The current through the magnetizing inductance of the transformer, referred to the primary side.

Nanostep Probe Signals

See Fig. 261 for the probe signal positions.

Fig. 261 Probes for the Flyback Converter with Snubber

Input current

The current flowing into the primary side of the transformer.

Output current

The current flowing into the secondary side of the transformer.

Switch current

The current flowing into the active semiconductor switch.

Magnetizing current

The current through the magnetizing inductance of the transformer, referred to the primary side.

Gate signal

The gate signal of the active semiconductor switch.