shows the H-bridge circuit. M1 and M2 are
P12PF06 P-channel MOSFET as the high-side switching
elements. M3 and M4 are IRF630 N-channel MOSFET as the
low-side switching elements. Another two IRF630 N-channel
MOSFET, M5 and M6 are needed as the driver to turn on the
M1 and M2. The torque of the motor can be controlled by
control the current flow through the motor as the torque is
directly proportional to the current across it. This can be
adjust by vary the duty cycle of PWM signal which feed into
M5 or M6. Base on [10], increase the drain to source voltage
(Vds), will increase the drain current (Id) of the MOSFET as
well. Changing the duty cycle of PWM signal will change
the average output voltage which is known as Vgs, when there
are changes in Vgs, Id which is the current that flow through
the motor will change as well. This is how the torque of the
motor being controlled