System and method for controlling regenerative braking force of a vehicle

A vehicle comprising:

• a fuel cell that receives supply of fuel gas and generates electric power;
• a motor that is driven by a generated electric power of the fuel cell;
• an electric power consuming auxiliary machine that consumes electric power to be driven;
• a mechanical brake that generates a vehicle braking force corresponding to depression of a brake pedal;
• a secondary cell that is capable of being charged and discharged;
• and
• a deceleration control unit that is configured to execute vehicle deceleration in a situation without the depression of the brake pedal, while assisting a regenerative braking force to be obtained by a regenerative control of the motor, with the vehicle braking force by the mechanical brake,
• wherein the deceleration control unit is configured to, when performing the vehicle deceleration in the situation without the depression of the brake pedal, calculate a deceleration force necessary for the vehicle deceleration while being separated into the regenerative braking force of the drive motor and the vehicle braking force of the mechanical brake;
• the deceleration control unit is configured to set the regenerative braking force to be obtained by the regenerative control to an upper limit regenerative braking force corresponding to a maximum electric power that the electric power consuming auxiliary machine is capable of consuming;
• when the electric power consuming auxiliary machine is capable of the maximum electric power, the regenerative electric power associated with regenerative braking is consumed by the electric power consuming auxiliary machine and consumption of the regenerative electric power by charge of the secondary cell is avoided;
• when the electric power consuming auxiliary machine is incapable of consuming the regenerative electric power to the maximum electric power, the secondary cell consumes residual regenerative electric power by charge of the secondary cell;
• and
• in a case where a target vehicle braking force as a deceleration target is greater than the upper limit regenerative braking force of the motor, the deceleration control unit is configured to make up for a difference between the target vehicle braking force and the upper limit regenerative braking force of the motor, with the vehicle braking force by the mechanical brake.