Dual Active Bridge

Description of the Dual Active Bridge converter in Schematic Editor. This converter block uses the dedicated DC-DC Converter solver FPGA hardware resource in order to reduce the simulation step.

A block diagram and input parameters for the Dual Active Bridge converter are given in Table 1.

Table 1. Dual Active Bridge converter component in Schematic Editor
component component dialog window component properties

Dual Active Bridge converter

  • Control
    • Control (Digital inputs, Internal modulator)
    • SA_1 (digital input selection for switch SA_1)
    • SA_2 (digital input selection for switch SA_2)
    • SA_3 (digital input selection for switch SA_3)
    • SA_4 (digital input selection for switch SA_4)
    • SB_1 (digital input selection for switch SB_1)
    • SB_2 (digital input selection for switch SB_2)
    • SB_3 (digital input selection for switch SB_3)
    • SB_4 (digital input selection for switch SB_4)
    • gate_logic (active high, active low)
    • Gate control enabling - A (enables usage of external digital signal to enable the switching of side A)
    • Sen - A (digital input selection for PWM enable for side A)
    • Sen_logic - A (active high, active low)
    • Gate control enabling - B (enables usage of external digital signal to enable the switching of side B)
    • Sen - B (digital input selection for PWM enable for side B)
    • Sen_logic - B (active high, active low)
  • Electrical
    • Enable Series Capacitor (Adds capacitor connected in series with inductor)
    • L (Dual Active Bridge inductor inductance)
    • C (Capacitor capacitance - visible if Enable Series Capacitor is checked)
    • R series (Resistance of series connected resistor
    • Transformer turns ratio (B/A) (Defines internal transformer ratio between sides B and A)
  • Extras
    • Short-circuit resistance - A (Resistance for side A used to calculate short circuit current if side A is shorted)
    • Short-circuit resistance - B (Resistance for side B used to calculate short circuit current if side B is shorted)

Digital inputs, when selected as the Control parameter, enables you to assign gate drive inputs to any of the digital input pins. For example, if SA_1 is assigned to 1, the digital input pin 1 will be routed to the SA_1 switch gate drive. In addition, the SA1_logic parameter is set to either active high (i.e. high-level input voltage VIH which turns on the switch), or active low (i.e. low-level input voltage VIL which turns on the switch). The gate drive logic depends on your external controller design.

Internal modulator, when selected for Control parameter, enables you to use the internal PWM modulator for driving switches instead of digital input pins. In this configuration, additional component inputs will be present. En input is used to enable/disable switching. In_a1, In_a2, In_b1, and In_b2 are used as referent signal inputs for the corresponding internal PWM modulator in legs A1, A2, B1, and B2, respectively. Additionally, Offset_a1, Offset_a2, Offset_b1, and Offset_b2 are used as carrier offsets for the corresponding internal PWM modulator in legs A1, A2, B1, and B2, respectively. If Variable carrier frequency is selected as the Operation mode for the Dual Active Bridge's internal modulator, an additional port Freq will be present. This port is used as a frequency input for the internal PWM modulator.

Short-circuit resistance - A and Short-circuit resistance - B are used to define the resistance that will be taken into consideration if some of the legs goes to short-circuit mode. Short-circuits are modelled using short-circuit resistance, which means that if a leg is in short-circuit mode, current drawn from its corresponding DC side will be Vdc_A(B)/Short-circuit resistance - A(B), where Vdc_A(B) is the DC voltage of the corresponding DC side.

Figure 1. A schematic block diagram of a Dual Active Bridge converter component with corresponding switch naming

Model description

The Dual Active Bridge runs on a dedicated hardware solver module DC-DC Converter Solver, that is highly optimized to simulate the dynamics of fast-switching converter topologies with enhanced resolution. For more details, check DC-DC Converter Solver. This means that the Dual Active Bridge converter block does not utilize the same resources that are typically used for other converter blocks, so the weight of the Dual Acitve Bridge converter is 0.

Electrical circuit interface

The Dual Active Bridge uses the DC-DC Converter Solver hardware resource. As it is described in Electrical circuit interface, every component that uses the DC-DC Converter Solver hardware resource contains an interfacing electrical circuit towards the rest of the circuit. The Dual Active Bridge component in the Typhoon HIL Schematic Editor Library uses the current source interface. The interface is formulated in such a way that the voltages are inputs to the dedicated DC-DC Converter solver core, while the currents are outputs from the dedicated DC-DC Converter solver core. Figure 2 shows the circuit interface of the Dual Active Bridge comoponent. Besides IA and IB which directly affect the surrounding circuit, there are additional component outputs:

  • i_L - represents the inductor's current
  • v_C - represents the capacitor's voltage (available if Enable Series Capacitor is active)
  • v_ac_A and v_ac_B - AC voltages for sides A and B, respectively.

Placement of all measurements is shown at Figure 1

Figure 2. Circuit interface of a Dual Active Bridge converter component

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.