Flyback converter

This section describes flyback converters

A block diagram and input parameters for flyback converter switching blocks are given in Table 1.

Table 1. The flyback converter component in the HIL Toolbox
component component dialog window component parameters

Flyback converter

  • General tab:
  • Control (Digital inputs, Internal modulator, Model)
  • S1(1..32)
  • gate_logic (active high, active low)
  • Transformer tab:
  • Number of turns of the primary winding (n1)
  • Number of turns of the secondary winding (n2)
  • Leakage inductance of the primary winding (L1)
  • Initial current on primary side (I1)
  • Leakage inductance of the secondary winding (L2)
  • Initial current on secondary side (I2)
  • Magnetization Inductance (Lm)
  • Primary winding resistance (R1)
  • Secondary winding resistance (R2)
  • Equivalent resistance representing the iron core losses (Rm)
Weight = 1

A schematic block diagram of the flyback switching block is given in Figure 1. It consists of a single phase two winding transformer, IGBT and a diode.

Digital inputs, when selected for Control parameter, enables the user to assign gate drive inputs to any of the digital input pins (from 1 to 32). For example, if S1 is assigned to 1, the digital input pin 1 will be routed to the S1switch gate drive. In addition, gate_logic parameter selects either active high (High-level input voltage VIH turns on the switch) or active low (Low-level input voltage VILturns on the switch )gate drive logic depending on the users external controller design.

Internal modulator, when selected for Control parameter, enables the user to use internal PWM modulator for driving IGBT switch instead of digital input pins. In this configuration, two additional component inputs will be present. En input is used as enable/disable and In is used as referent signal input for internal PWM modulator.

Model, when selected for Control parameter, enables the user to set the IGBT gate drive signal directly from signal processing model. The input pin gate appears on the component. It is one element input, where that value controls S1 switch gate. When controlled from the model, logic is always active high.

Figure 1. Schematic block diagram of flyback converter with corresponding switch naming

Currents of the transformer inductances can be found in the list of analog outputs by names shown in Analog output variable naming for the flyback switching block (internal to the component).

Analog output variable naming for the flyback switching block (internal to the component)

Analog output variable name Description
Lm_(name) Current of magnetizing inductance of the transformer
L1_(name) Current of primary side leakage inductance of the transformer
L2_(name) Current of secondary side leakage inductance of the transformer

Digital Alias

If a converter is controlled by digital inputs, an alias for every digital input used by the converter will be created. Digital input aliases will be available under the Digital inputs list alongside existing Digital input signals. The alias will be shown as Converter_name.Switch_name, where Converter_name is name of the converter component and Switch_name is name of the controllable switch in the converter.