Forward converter

Description of the Forward Converter component in Schematic Editor

A block diagram and input parameters for the Forward converter switching blocks is given in Table 1.

Table 1. The Forward converter component in the Schematic Editor core library
component component dialog window component parameters

Forward
  • General tab:
    • Control (Digital inputs, Internal modulator, Model)
    • S1 (digital input selection for switch S1)
    • S1_logic (active high, active low)
    • Gate control enabling (allows an external digital signal to enable switching)
    • Sen (digital input selection for gate control)
  • Transformer tab:
    • Number of turns of the primary and the tertiary (reset) winding (n1)
    • Number of turns of the secondary winding (n2)
    • Leakage inductance of the primary winding (L1)
    • Initial current on primary the side (I1)
    • Leakage inductance of the secondary winding (L2)
    • Initial current on the secondary side (I2)
    • Leakage inductance of the tertiary (reset) winding (L3)
    • Initial current on the tertiary (reset) side (I3)
    • Magnetization Inductance (Lm)
    • Primary winding resistance (R1)
    • Secondary winding resistance (R2)
    • Tertiary winding resistance (R3)
    • Equivalent resistance representing the iron core losses (Rm)
Weight = 1

A schematic block diagram of the Forward switching block is given in Figure 1 with its corresponding switch arrangement and naming. It consists of a Single phase three winding transformer, an IGBT, an IGBT and three diodes.

Digital inputs, when selected as the Control parameter, enables gate drive inputs to be assigned 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 S1 switch gate drive. In addition, the gate_logic parameter is set to either active high (i.e. high-level input voltage which turns on the VIH switch) or active low (i.e. low-level input voltage which turns on the VIL switch). The gate drive logic depends on the external controller design under test.

The Internal modulator, when selected as the Control parameter, enables the internal PWM modulator to drive the S1 switch instead of the digital input pins. In this configuration, two additional component inputs will be present. The En input is used to enable/disable PWM modulator control, while In is used as the reference signal input for the internal PWM modulator.

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

Figure 1. Schematic block diagram of a Forward Converter switching block 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 Forward switching block (internal to the component).

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

Analog output variable name Description
name.L1 Current of primary side leakage inductance of the transformer.
name.L2 Current of secondary side leakage inductance of the transformer.
name.L3 Current of tertiary side leakage inductance of the transformer
name.Lm Current of magnetizing 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.