Optimized control of the operation of one or more traction systems of a train for entering and exiting from a coasting condition

A train comprising a plurality of railway vehicles, each of which comprises:

• a respective traction system, which includes a respective electric motor operable by a respective electronic drive system;
• wherein the respective electric motor of each traction system is an asynchronous motor and the respective electronic drive system is an inverter system, or the respective electric motor of each traction system is a synchronous DC motor and the respective electronic drive system is a chopper-type system;
• a respective electronic control unit coupled to the respective traction system;
• wherein the train comprises a central control unit connected to the electronic control units of the railway vehicles, and being configured to:
• receive quantities indicative of a strain request for the train and of an available strain for each traction system;
• select one or more traction system on the basis of the received quantities;
• send traction commands to the respective electronic control units of the selected traction systems;
• and
• send coasting commands to the respective electronic control units of the non-selected traction systems;
• wherein, for each railway vehicle, the respective electronic control unit is configured to:
• determine an occurrence of a coasting condition when the electronic control unit receives a coasting command from the central control unit;
• when the electronic control unit determines the occurrence of the coasting condition, control an operation of the respective electronic drive system so as to cause the respective electric motor to undergo a magnetic flux reduction and, during the magnetic flux reduction of the respective electric motor, said controlling the operation comprises:
• monitoring the magnetic flux of the respective electric motor,
• determining whether the magnetic flux of the respective electric motor decreases under a magnetic flux threshold, and
• when the electronic control unit detects that the magnetic flux of the respective electric motor has decreased under the magnetic flux threshold, switch off the respective electronic drive system, and
• determine an occurrence of an exit condition from the coasting condition when the electric control unit receives a traction command from the central control unit;
• when the electronic control unit determines the occurrence of the exit condition, determine whether the respective electronic drive system is on or off, wherein the electronic control unit is configured to determine that the respective electronic drive system is;
• on when the magnetic flux of the respective electric motor exceeds the magnetic flux threshold, or
• off when the magnetic flux of the respective electric motor is lower than the magnetic flux threshold;
• when the electronic control unit determines the occurrence of the exit condition and the electronic control unit also determines the respective electronic drive system is on, cause a torque of the respective electric motor to start increasing;
• when the electronic control unit determines the occurrence of the exit condition and the electronic control unit also determines the respective electronic drive system is off, switch on the respective electronic drive system, control the operation of the respective electronic drive system so that the respective electric motor undergoes a magnetic flux increase, and, during said magnetic flux increase of the respective electric motor;
• monitor the magnetic flux of the respective electric motor,
• determine whether the magnetic flux of the respective electric motor exceeds said magnetic flux threshold, and
• when the electronic control unit determines that the magnetic flux of the respective electric motor has exceeded the magnetic flux threshold, cause the torque of the respective electric motor to start increasing.