Flyback Converter with Snubber

Purpose

Flyback converter with leakage inductance and snubber diode, optimized for Real-Time Simulations on the RT Box.

Library

Electrical / Nanostep

Description

This component implements a flyback converter 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.

Both sides of the converter have current source behavior. The primary side must be connected directly to a capacitor or a voltage source.

The component offers two configurations:

Nanostep / Switched

The power semiconductors are modelled as ideal switches controlled by instantaneous logical gate signals. A switch is turned on when the corresponding gate signal is true.

In Nanostep / Switched configuration, C code generated from this component is suitable for real-time simulations on the RT Box, where it is executed on a Nanostep solver. In this case, connect the gate inputs to PWM Capture blocks from the RT Box component library.

Sub-cycle average

Each gate input is controlled by a floating-point number with values between \(0\) and \(1\), representing the relative on-time of the corresponding semiconductor over one simulation step, as described in Sub-cycle Averaging.

In Sub-cycle average configuration, C code generated from this component is suitable for real-time simulations on the RT Box, where it is executed on the CPU or FlexArray solver. In this case, connect the gate inputs to PWM Capture blocks from the RT Box component library.

Note

This component has a Nanostep solver weight of \(3\), indicating that it occupies one entire Nanostep solver for Real-time Simulations on the RT Box.

Note

DC voltage clamping through diodes is not permitted. Therefore, ensure that DC voltages across diodes are not negative.

Parameters

Certain parameters are associated with specific components. The corresponding component labels such as \(\mathrm{L}\), \(\mathrm{C}\), etc., are shown in Fig. 265.

Configuration

Selects the component configuration. See the descriptions of Nanostep / Switched and Sub-cycle average above.

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

Use this setting to choose between IGBT and MOSFET for the symbol of the active semiconductor switches. This setting only affects the schematic representation and does not change the electrical behavior of the component.

Primary inductance

A non-zero scalar specifying the primary-side inductance \(\mathrm{L_1}\), including the transformer leakage inductance and any external series-connected inductor, in henries \((\mathrm{H})\).

Primary winding resistance

A scalar specifying the primary-side winding resistance \(\mathrm{R_{L1}}\), in ohms \((\Omega)\).

Magnetizing inductance

A non-zero scalar specifying the magnetizing inductance of the transformer \(\mathrm{L_m}\), referred to the primary side, in henries \((\mathrm{H})\).

Turns ratio

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

Secondary inductance

A non-zero scalar specifying the secondary-side series inductance \(\mathrm{L_2}\), including the transformer leakage inductance and any external inductors, in henries \((\mathrm{H})\).

Secondary winding resistance

A scalar specifying the secondary-side winding resistance \(\mathrm{R_{L2}}\), in ohms \((\Omega)\).

Probe Signals

See Fig. 265 for the probe signal positions.

Magnetizing current

The current through the inductor \(\mathrm{L_m}\), in amperes \((\mathrm{A})\), defined positive in the direction of the arrow.

Nanostep Probe Signals

Input current

The current at the primary-side converter terminals, in amperes \((\mathrm{A})\), defined positive in the direction of the arrow.

Output current

The current at the secondary-side converter terminals, in amperes \((\mathrm{A})\), defined positive in the direction of the arrow.

Switch current

The current flowing in the active semiconductor switch, in amperes \((\mathrm{A})\), defined positive in the direction of the arrow.

Magnetizing current

The current through the inductor \(\mathrm{L_m}\), in amperes \((\mathrm{A})\), defined positive in the direction of the arrow.

Gate signal

The gate signal applied to the active semiconductor switch.

Fig. 265 Probes for the Flyback Converter with Snubber

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↳ Added in PLECS 4.9.