Anti-spin control for a separately excited motor drive system

In a system having two or more electric motors, the electric motors adapted for being coupled to two or more wheels of an electric vehicle, each of the electric motors having armature and field coils which are independently excited by a source of voltage to generate armature and field currents, the armatures being connected in series to the voltage source, a method of controlling performance of the electric motors, comprising:

• detecting a condition in the system to ascertain when to deactivate one of the electric motors;
• identifying one of the electric motors to deactivate when the condition is detected;
• eliminating current in the identified one of the electric motors, the current being armature current or field current;
• providing armature current and field current to the one or more electric motors that are not identified as one of the electric motors to deactivate after the current is eliminated in the identified one of the electric motors;
• and
• automatically restoring the current in the identified one of the electric motors in response to a recovery event.

Apparatus for controlling performance of two or more DC motors used for driving an electric vehicle, each of the electric motors having armature and field coils which are independently excited by a source of voltage to generate armature and field currents, comprising:

• a source of DC voltage;
• two or more motor armatures connected in series to the voltage source through an armature control circuit to provide independent control of the motor armatures;
• two or more motor field windings coupled to the two or more motor armatures and connected to the source of voltage through a field winding control circuit to provide control of the two or more motor field windings independent of the armatures;
• a detection mechanism for detecting a condition in one of the motors, the condition when in a first state indicating that one of the motors is to be deactivated and when in a second state indicating that none of the motors are to be deactivated;
• an identification mechanism coupled to the detection mechanism, the identification mechanism adapted for identifying one of the motors to deactivate when the condition is in the first state;
• a motor controller coupled to the armatures and the field windings, the motor controller being adapted for eliminating current in the identified motor when the condition is in the first state and for restoring current in the identified motor in response to a recovery event, the current being armature current or field current;
• a drive mechanism for providing armature current and field current to the motors that are not identified by the sensing mechanism as one of the motors to deactivate after the motor controller has eliminated the current in the identified motor;
• and
• a recovery mechanism coupled to the motor controller, the recovery mechanism being adapted for restoring current in the identified motor in response to a recovery event that is a user-initiated event performed by a user of the vehicle.

Apparatus for controlling performance of two or more DC motors used for driving an electric vehicle, each of the electric motors having armature and field coils which are independently excited by a source of voltage to generate armature and field currents, comprising:

• a source of DC voltage;
• two or more motor armatures connected in series to the voltage source through an armature controller to provide independent control of the motor armatures;
• two or more motor field windings coupled to the two or more motor armatures and connected to the source of voltage through a field winding controller to provide control of the two or more motor field windings independent of the armatures;
• a detection mechanism for identifying one of the motors to deactivate;
• a shunting mechanism coupled to the detection mechanism and to the field windings for eliminating field current in the identified motor;
• a drive mechanism for providing armature current and field current to the motors that are not identified by the detection mechanism as one of the motors to deactivate after the shunting mechanism has eliminated field current in the identified motor;
• and
• a recovery mechanism adapted for restoring field current in the identified motor in response to a recovery event, wherein the recovery event is ascertained from at least one of a detection of movement of the vehicle for a specified period of time, detection of movement of the vehicle for a specified distance, and detection of movement of the vehicle in a desired direction.