In figure 6.3 the diagram of a three phase bridge control is shown along with
its switching sequence. When the motor is running, current flows through
two phases at a time. The current control is done by two switches, an upper
switch and a lower switch. The upper switch is controlled by a switching
control signal with a period of 66[μs], 15.15[kHz], and a various duty cycle.
By doing this the current through the phases is chopped, causing the current
to be within a certain level, or hysteresis.