Implementation of a bidirectional three-phase dual-active-bridge DC converter for electric vehicle applications

Hybrid Modulation of Bidirectional Three-Phase Dual-Active-Bridge DC Converters for Electric Vehicles

“…Thus the volume of the switching-ripple filters can be significantly reduced in the 3ΦDAB converter. However, similarly to 1ΦDAB converter, the 3ΦDAB converter with phase-shifted modulation still performs poor efficiency at low-power operation [16][17][18][19][20][21]. In [20], a hybrid modulation strategy was proposed for the 3ΦDAB converter, including phase-shifted, triangular and trapezoidal modulations.…”

“…The authors have presented the 3ΦDAB converter with hybrid modulation in previous research [21]. The converter is able to switch its modulation between phase-shifted and trapezoidal modes autonomously to maintain efficiency even in the light-load condition.…”

“…Thus the power transfer P D can be determined based on integrating both voltage and current. As shown in Equations (1) and (2), P D is dependent on the phase-shift angle δ between two sides of the transformer [18,21]:…”

“…Thus the power transfer PD can be determined based on integrating both voltage and current. As shown in Equations (1) and (2), PD is dependent on the phase-shift angle δ between two sides of the transformer [18,21]: The parameter d is defined as the voltage gain, equal to (NVbat/Vi), and ω is the switching frequency in radians per second. The theoretical phase-shifted angle δ for a corresponding PD also can be expressed as the following Equations (3) and (4) …”

“…Figure 2b shows the typical voltage and current waveforms of trapezoidal modulation. The power conversion PT can be expressed as Equations (6) and (7) [18,21]. Controllable variables include phase-shifted angle δT, the primary-and secondary-side duty cycles D1, D2.…”