Improvement Method for Light Load Efficiency of DAB Converter with Wide Input Voltage Range

A Phase-Shift Control Method of Triple-Active-Bridge Converter for Reducing Power Loss Under Light Load Condition

“…The proposed phase-shift control method of the TAB converter generates three phase-shift control values, 1, 2, and 3, from two control values, REF1 and REF2, corresponding to each of the two output ports. Here, the proposed method behaves similarly to the previously described method (8) under the condition that the voltage and power of the two output ports are balanced. The phase-shift control values 1, 2, 3 shown in Fig.…”

“…4 (b). The phaseshift control method of the DAB converter presented in a previous study (8) used a table that generates two phase-shift control values from a single control value in order to improve both current controllability and light load losses. The proposed phase-shift control method of the TAB converter generates three phase-shift control values, 1, 2, and 3, from two control values, REF1 and REF2, corresponding to each of the two output ports.…”

“…Table 2 summarizes the experimental results related to the controllability. The operating modes are classified according to the bridge voltage level of each port by using the operation mode where REF1 and REF2 are equivalent as a base mode, based on (8) . The extended mode is a new mode resulting from the addition of different phase-shift control amounts θ2 and θ3 at the two output ports, as shown in Fig.…”

“…Table 2. Operation mode classification based on experimental results: based on the report (8) According to the discharge operation mode, Mode 1(+), the base mode, becomes Mode 1'(+), in which the bridge voltage level of the output port to increase the power changes from 5 to 3 and the bridge voltage level of the output port to decrease the power changes from 5 to 9, with REF1 being larger than REF2. It was confirmed that Mode 2(+) becomes Mode 2'(+), in which the bridge voltage level of the output port for reducing the power changes from 3 to 5, or Mode 2''(+), in which the bridge voltage level of the output port changes from 3 to 7, under the above conditions.…”

“…Since the TAB converter transfers power between the three ports, there are two states in which either one power-supplying bridge and two power-receiving bridges, or two power-supplying bridges and one power-receiving bridge are generated. Previous studies aiming at reactive power suppression of the DAB converter (7), (8) show a method of stopping the switching of one leg of the power-receiving bridge to suppress reactive power circulating through the transformer; however, these studies do not include a method for converters with multiple power-supplying bridges or multiple power-receiving bridges. Figure 3 shows a conceptual diagram of the power direction relationship between each port in the TAB converter.…”