Active snubber circuit for electrical rotary actuator

A motor drive interposed between an electrical power source and a limited angle torque electrical motor, wherein the electrical motor is arranged driven in an H-bridge switch network configuration comprising four motor switches, including a first series of first and second switches in series and a second series of third and fourth switches in series, the motor connecting first and second series at a location between the first and second switches and between the third and fourth switches, wherein the motor is selectively modulated between two of three states to produced a selected torque output in a selected angular direction including a first state where the first and fourth switches are closed, a second state where the second and third switches are closed, and a third state where the second and fourth switches are closed, the electrical motor adapted to produce an inductive flyback current when switching between states, the motor driver comprising:

• a reverse voltage protector in series between the electrical power source and the electrical motor allowing proper flow of electrical power to the electrical motor;
• a capacitor arranged in parallel circuit with the motor between electrical motor and the diode;
• an electromagnetic interference filter in series with the electrical motor between the electrical motor and the diode;
• and
• an active snubber circuit arranged in parallel circuit with the electrical motor between the reverse voltage protector and the electrical motor, the active snubber circuit comprising a switch having a sensor responsive to the inductive flyback current and a resistor in series with the switch for regulating electrical current flow.