Regenerative braking apparatus and method for direct current motors

A control apparatus for controlling the regenerative braking of a motor electrically connected to a D.C. power source comprising:

• control means for generating at least one of a drive mode signal, a transient mode signal, a first regenerative braking mode signal and a second regenerative braking mode signal in response to a plurality of operating parameter signals;
• drive mode means responsive to said drive mode signal for causing said motor to operate in a drive mode such that said motor is driven in a first direction of rotation by said D.C. power source;
• transient mode means responsive to said transient mode signal for causing said motor to transition from said drive mode to a transient mode such that a flux builds up in an armature winding and a field winding of said motor, said flux generating a current flow through a transient circuit path running through said motor;
• first regenerative braking mode means responsive to said first regenerative braking mode signal for causing said motor to transition from said transient mode to a first regenerative braking mode such that said current flow switches from said transient circuit path to a charging circuit path interconnecting said motor and said D.C. power source, said flux charging said D.C. power source and generating a requested braking torque in said motor in a second direction of rotation opposing said first direction of rotation, said requested braking torque having a constant magnitude;
• and
• second regenerative braking mode means responsive to said second regenerative braking mode signal for causing said motor to transition from said first regenerative braking mode to a second regenerative braking mode such that said flux continues to charge said D.C. power source while generating a diminishing braking torque, said diminishing braking torque having a maximum magnitude that is less than said constant magnitude of said requested braking torque.

A control apparatus for controlling the regenerative braking of a motor electrically connected to a D.C. power source comprising:

• control means for generating a drive mode signal in response to a request for an increase in motor speed, a transient mode signal in response to a request for a decrease in motor speed, a first regenerative braking mode signal in response to one of a lapse of predetermined time delay or a request for a reduction in said decrease in motor speed, and a second regenerative braking mode signal in response to an inability to maintain said requested decrease in motor speed;
• drive mode means responsive to said drive mode signal for causing said motor to operate in a drive mode such that said motor is driven in a first direction of rotation by said D.C. power source;
• transient mode means responsive to said transient mode signal for causing said motor to transition from said drive mode to a transient mode such that a flux builds up in an armature winding and a field winding of said motor, said flux generating a current flow through a transient circuit path running through said motor;
• first regenerative braking mode means responsive to said first regenerative braking mode signal for causing said motor to transition from said transient mode to a first regenerative braking mode such that said current flow switches from said transient circuit path to a charging circuit path interconnecting said motor and said D.C. power source, said flux charging said D.C. power source and generating a requested braking torque in said motor in a second direction of rotation opposing said first direction of rotation, said braking torque having a constant magnitude;
• and
• second regenerative braking mode means responsive to said second regenerative braking mode signal for causing said motor to transition from said first regenerative braking mode to a second regenerative braking mode such that said flux continues to charge said D.C. power source while generating a diminishing braking torque, said diminishing braking torque having a maximum magnitude that is less than said constant magnitude of said requested braking torque.

A method of regenerative braking a motor electrically connected to a D.C. power source comprising the steps of:

• generating at least one of a drive mode signal, a transient mode signal, a first regenerative braking mode signal, and a second regenerative braking mode signal in response to reception of a plurality of operating parameter signals;
• operating said motor in a drive mode in response to reception of said drive mode signal such that said motor is driven in a first direction of rotation by said D.C. power source;
• causing said motor to transition from said drive mode to a transient mode in response to reception of said transient mode signal such that a flux builds up in an armature winding and a field winding of said motor, said flux generating a current flow through a transient circuit path running through said motor;
• causing said motor to transition from said transient mode to a first regenerative braking mode in response to reception of said first regenerative braking mode signal such that said current switches from said transient circuit path to a charging circuit path interconnecting said motor and said D.C. power source, said charging circuit path permitting said flux in said motor to charge said D.C. power source and to generate a requested braking torque in said motor in a second direction of rotation opposing said first direction of rotation, said requested braking torque having a constant magnitude;
• and
• causing said motor to transition from said first regenerative braking mode to said second regenerative braking mode in response to reception of said second regenerative braking mode such that said flux continues to charge said D.C. power source while generating a diminishing braking torque, said diminishing braking torque having a maximum magnitude that is less than said constant magnitude of said requested braking torque.

A control apparatus for controlling the regenerative braking of a motor electrically connected to a D.C. power source comprising:

• a controller that generates at least one of a drive mode signal, a transient mode signal, and a first regenerative braking mode signal in response to reception of a plurality of operating parameter signals;
• drive mode circuitry responsive to said drive mode signal to cause said motor to operate in a drive mode such that said motor is driven in a first direction of rotation by said D.C. power source;
• transient mode circuitry responsive to said transient mode signal to cause said motor to transition from said drive mode to a transient mode such that a flux builds up in an armature winding and a field winding of said motor, said flux generating a current flow through a transient circuit path running through said motor;
• and
• first regenerative braking mode circuitry responsive to said first regenerative braking mode signal to cause said motor to transition from said transient mode to a first regenerative braking mode such that said current flow switches from said transient circuit path to a charging circuit path interconnecting said motor and said D.C. power source, said flux charging said D.C. power source and generating a requested braking torque in said motor in a second direction of rotation opposing said first direction of rotation, said braking torque having a constant magnitude.

A control apparatus for controlling the regenerative braking of a motor electrically connected to a D.C. power source comprising:

• a controller that generates at least one of a drive mode signal, a transient mode signal, a first regenerative braking mode signal, and a second regenerative braking mode signal in response to reception of a plurality of operating parameter signals;
• drive mode circuitry responsive to said drive mode signal to cause said motor to operate in a drive mode such that said motor is driven in a first direction of rotation by said D.C. power source;
• transient mode circuitry responsive to said transient mode signal to cause said motor to transition from said drive mode to a transient mode such that a flux builds up in an armature winding and a field winding of said motor, said flux generating a current flow through a transient circuit path running through said motor;
• first regenerative braking mode circuitry responsive to said first regenerative braking mode signal to cause said motor to transition from said transient mode to a first regenerative braking mode such that said current flow switches from said transient circuit path to a charging circuit path interconnecting said motor and said D.C. power source, said flux charging said D.C. power source and generating a requested braking torque in said motor in a second direction of rotation opposing said first direction of rotation, said braking torque having a constant magnitude;
• and
• second regenerative braking mode circuitry responsive to said second regenerative braking mode signal to cause said motor to transition from said first regenerative braking mode to a second regenerative braking mode such that said flux continues to charge said D.C. power source while generating a diminishing braking torque, said diminishing braking torque having a maximum magnitude that is less than said constant magnitude of said requested braking torque.