High efficient modular drive system — An ideal approach for green intralogistics applications

This paper introduces an efficient modular solution kit for intralogistic drives, which reduces the total energy consumption of all drives in an automated warehouse by more than 15%. The reduction of energy consumption results from the interaction of optimized components (motors, control techniques and regeneration units), which are described in detail in this paper. Different motor concepts like the induction motor, the synchronous reluctance motor and the permanent magnet synchronous machine are compared according to the special requirements for intralogistics applications. Different control techniques are presented in order to achieve sensorless and efficient-optimal operation of these motors. The sensorless control technique uses signal injection to detect the rotor position sufficiently exact also in case of speed near standstill. Efficient-optimal operation is achieved by reducing the motor current with regard to the torque (MTPA-control). Furthermore this paper introduces a regeneration unit that can be connected between the DC link of frequency inverters and the mains to feed back regenerative energy. The regeneration unit consisting of a buck converter, a synchronous inverter and a line-filter can work in parallel to commonly used uncontrolled rectifiers. Its functioning is shown with the help of measurement results of a 1kW laboratory prototype. The last section shows a demonstrator in which a conventional conveyer system (with induction motor and braking resistor) is compared with an optimized one using the presented components. Power versus time measurements show specific energy savings resulting from the interaction of the optimized components.