Brushless PM actuator for metal bending machine

This paper presents the design concepts and the test results of a Permanent Magnet synchronous motor (PMSM) for an electro-mechanical actuator used in high-performance sheet metal bending machine. The motor is directly integrated with the mechanical component in a rotating-ballscrew architecture in order to minimize the total inertia and the actuator´s size. The motion trajectory fits the classical profile with high-torque at low-speed and low-torque at high speed, which involves flux-weakening operation. A prototype has been manufactured using the design data of the optimization procedure. Due to mechanical considerations and the encumbrance limits, the proposed motor has the PMs directly glued on the surface of the steel nut that represents the “rotor”. Test results confirm the performance of the system and the goodness of the prototype.