Brushless Permanent Magnet Motor Design- P6 pdf

146 Chapter S Figure 6.8 Geometry for the torque calculation in the dual axial flux topology To understand this phenomenon, consider the magnet shown in Fig 6.8 Theflux entering the stator from a differential slice is 0, Vcc > 0, and Eb > As time progresses, the current decreases exponentially toward the negative value - (V cc + Eb)/R Upon reaching zero current, the diodes turn OFF, the energy in the inductor (0.5Li2) is returned to the supply, and the circuit rests If the circuit lacked freewheeling diodes, the inductor voltage would increase in amplitude until one or more switches are destroyed in an attempt to provide a current path for the inductor current In some situations, just one of the two switches is opened To illustrate this action, assume the conditions shown in Fig 7.6a and open only switch S ; let Si remain closed The path for decaying current flow in this case is through D3 and