Controlling device for railway electric car

A controlling device for a railway electric car, the controlling device including a plurality of electric motors and a slipping/sliding controlling unit that generates a torque command value so as to inhibit a slipping or sliding based on rotation speeds of the plurality of electric motors, wherein

• the slipping/sliding controlling unit includes:
• a reference rotation speed calculator that calculates a first reference rotation speed and a second reference rotation speed by using the rotation speeds of the plurality of electric motors;
• first adhesion level index generating units that are provided in correspondence with the electric motors respectively, and each of the first adhesion level index generating units receives, as an input, the first reference rotation speed and the rotation speed of a corresponding one of the electric motors and generates a first adhesion level index that is an index for an adhesion level between a wheel that is connected to the corresponding electric motor and a surface that is trodden by the wheel, based on an acceleration deviation that is a difference between an acceleration calculated by using the rotation speed of the corresponding electric motor and an acceleration calculated by using the first reference rotation speed and based on a speed deviation that is a difference between the rotation speed of the corresponding electric motor and the first reference rotation speed;
• a second adhesion level index generating unit that receives, as an input, the second reference rotation speed and generates a second adhesion level index value by multiplying the first adhesion level index value by a gain that has been generated based on an acceleration calculated by using the second reference rotation speed;
• and
• a torque command value generating unit that generates the torque command value based on the second adhesion level index value.