Control method based on real-imaginary decomposition at the switching frequency for multiple active bridge converters

Isolated multiple port DC/DC converters, such as the Multiple Active Bridge (MAB) converter, have many recent applications, such as interconnection between grids, isolated uninterruptible power sources (UPSs) and electric vehicle chargers. MAB converter is an attractive solution from the point of view of the hardware because of its symmetry and its capability to be extended to any number of bridges with a moderate number of components. However, the main challenge of this converter is the control method in order to achieve independent control between the different ports and to minimize recirculating currents. For that reason, three-port power converters have been already investigated, but many improvements can be done for a larger number of ports. This paper proposes to use a Fourier decomposition for the main power signals to separate their real and imaginary parts. As the signals work at the switching frequency, this decomposition is developed with analog electronics. Based on that, a general control method for regulating the power at the different ports is presented using the first harmonic component, which delivers most of the power. In this proposal, two nested control loops ensure accuracy for the DC power flow. Simulation and experimental results validate the proposal. The paper proposes an independent method of control of a multi active bridge converter based on a dq-decomposition at the switching frequency. The method allows a fast response and an independent control of bidirectional power flow in all of the ports.image