Peak shaving through closed-loop optimization applied to machine tools with periodic behaviour

Abstract

This paper deals with machine tools characterized by a periodic behaviour and high-power peaks that require an oversized electrical network and cause high costs because electrical utilities charge greatly each power peak. To solve this issue, a new peak-shaving methodology is proposed based on polynomial models and optimization, to reduce the power-consumption peaks height in machine tools with periodic behaviour. A test-bench that emulates the electrical behaviour of a machine tool is used in order to test the proposed method with real data. In the scenarios simulated, the peak height has been reduced between 35% and 15%.

Energy efficiency in discrete-manufacturing systems: Insights, trends, and control strategies

“…For example, currently, control systems oriented to prognosis and maintenance of manufacturing systems, based on the historical data, have been developed with the aim to predict and program the required changes or maintenance activities [107,108,109]. Additional to the prediction of maintenance tasks, strategies such as receding horizon control and advanced methods of process control (e.g., model predictive control (MPC)), have started to gain attention too, mainly, focusing on problems of energy efficiency and flexibility for planning and scheduling of processes at machine, line, and plant level [110,111,112,113].…”

“…Nonetheless, nowadays, it is considered that peripheral devices can be independently managed from machining devices in pro of energy efficiency and without to compromise the machining operation, since these devices could or could not have a periodic behavior. Based on this fact, application of MPC controllers for selective on/off switching of these devices, based on their own dynamic behavior and the total energy consumption of the machine have gained interest as a control strategy oriented to improve the energy efficiency of manufacturing systems [114,110,115].…”

An optimization-based control strategy for energy efficiency of discrete manufacturing systems

“…Therefore, although the off-line optimization of the activation sequence of manufacturing devices (including or not the peripheral devices) allows improving the energy efficiency of a manufacturing system by minimizing its global energy consumption, other concerns must be taken into account to develop strategies that can be successful in real time and when disturbances take place. In this sense, strategies that avoid surpassing the nomi-nal contracted power, e.g., by using selective on/off switching of the peripheral devices [10], could be considered.…”