Abstract: Capacitor voltage balancing techniques are described for a 3-level 3-level dual-active-bridge converter that controls the duration of a zero voltage state of the low voltage (LV) and medium (MV) side transformer voltages based on a voltage difference between the upper and lower capacitors of both the LV and MV sides independently, the power delivered (P), and the LV and MV DC voltages. This control varies the angle to maintain the power requirement, which induces the additional voltage drop across the transformer inductance to produce the required current to flow through the capacitors and balance the capacitor voltages.

Abstract: Techniques are described to smooth start a multilevel dual active bridge converter by pre-charging the capacitors present on the converter without requiring any additional hardware. Various phase shift angles determine the power delivered by the dual active bridge converter. By using the techniques, a predefined amount of time is reserved to pre-charge the capacitors until the capacitors reach a desired voltage after which time the smooth starting of the dual active bridge converter is initiated.

Abstract: A fundamental harmonic matching control technique (FHMT) can optimize the use of the switching devices needed to operate a dual active bridge DC/DC converter, which reduces the peak and RMS currents thereby reducing the switching power losses. The FHMT control techniques can also reduce the current rating of the switching devices, transformer, and the inductor of the dual active bridge DC/DC converter.

Abstract: A fundamental harmonic matching control technique (FHMT) can optimize the use of the switching devices needed to operate a dual active bridge DC/DC converter, which reduces the peak and RMS currents thereby reducing the switching power losses. The FHMT control techniques can also reduce the current rating of the switching devices, transformer, and the inductor of the dual active bridge DC/DC converter.