Drone applications require high cell count battery packs to support longer flying distances and flight times. As an example, consider a 14-series (14s) Liion battery pack architecture where the working voltage is 50 V to 60 V. When designing a DC/DC power supply for such a system, one of the challenges is how to select the maximum input voltage rating. A large voltage excursion can occur at the node designated VM in Figure 1.
To understand the modes of operation of a motor driver, consider the schematic diagram of Figure 2. The battery stack powers a brushed-DC (BDC) motor, M1 , through the forward current path designated as loop 1, and electric power converts to the rotational kinetic energy of the motor during this period.
Conversely, when the motor decelerates or changes its direction of rotation, it acts as a generator and the resultant back EMF returns energy to the input through the driver using current loop 2. Although this regenerative behavior may be considered advantageous in terms of improving overall system efficiency, it can result in a large reverse current and consequent voltage overshoot at the supply input.