Motor controller
An electric drive is a drive with an electric motor ( or a plurality of electric motors), which (or which ) is controlled by a control system. If the engine power is large, electronic power actuators to be interposed between the control and the electric motor (or motors ). You are then part of the electric drive.
Often the control of the electric drive is designed in the shape of a speed, torque, position, velocity, or more variable control. In this case, a control circuit, one or more other loops in each case be underlain or not.
Mostly are separate components for the switching on and off of the drive and the necessary safety and monitoring facilities for the practical operation, further comprising a source of energy in the form of a power source, a generator (in the form of a fuel cell ) or a battery (or a double layer capacitor (about provided in the form of ultra-or super caps) ).
Functions, motion control aspects and implementation
When electric power electrical energy is converted into mechanical kinetic energy. In this case, it can be transformed into both a rotational movement and in a linear motion ( or a controlled linear drive electric motor with a flanged rotating worm gear ). In electric drives are particularly at position controls the elementary movements "rotation" and "translation" no uniform movements. Rather, through the respective control or more defined movement (i.e., movement pattern as a function of time ) is specified. When torque and speed control, things are at least intermittently different: in a given interval can be uniformly carried out a specific movement.
In professional use drive controllers are implemented digitally today. Only in the hobby (about the model ), or in rare cases in the field of small drives are realized yet analogous arrangements. In terms of hardware come in the case of digital implementations microcontroller with Ein-/Ausgabe-Einheiten with analog -to-digital and digital-to- analog converters and communication interfaces are used. Software default, drive controls in the form of direct digital control algorithms implemented additional controls (eg for sensors and actuators) in the form of Ein-/Ausgabe-Steuerbefehlen exchange and communication in the form of interface communication routines.
Power electronic actuators
Efficiency and practical operating characteristics
Compared to other types of drives (eg combustion engine) electric drives have a very good efficiency. Efficiencies of up to 99 % are not uncommon in large machines. A distinction is made between drives with lower power ( small electrical drives) and those of higher performance. In the power range of about 900-1100 Watts Electric motors have an efficiency of typically 70-90 %. The efficiency can However, with increasing power to about 99% increase (growth laws of electrical machinery). In contrast to gasoline, or diesel drive electric drives have higher speeds and voltages, lower weight and are also environmentally friendly and more reliable than their counterparts. Moreover, they can be stopped immediately in an emergency (subject to the expiry of the rotating masses due to the moment of inertia ) by disconnecting the electrical power system.
Areas of application
The applications range from miniature drives with a few milliwatts of power (eg, drive motors for CD players ) over medium-power applications ( vacuum cleaners, kitchen appliances ) to highest achievements in the industry and in transport ( drives of coal mills, drives of electric trains, subway lanes, etc.).
The possibility of the electric drive system to utilize solar energy, the drive makes probably be invaluable for the future. Electric drives in the transport sector are to be separated with respect to the prospects of success of the energy supply. While battery electric vehicles ( BEVs ) outside of locally operating vehicles ( operating in the interior or on farms ) so far no success source is the electric drive in overhead line powered systems ( trolleybus, electric locomotive ), in diesel-electric drives, hybrid electric vehicles ( hybrid drive ) but also fuel cell vehicles more widespread. New performance leaps in Akkumulatortechnik, such as the lithium -ion battery or lithium-titanate battery with nano - technology open in the electromobility new market opportunities for electric vehicles.
History
In the early industrialization of the electric motor has replaced very soon the steam engine and the wind and water mills. This happened as soon as the distribution of electrical energy was available. From the beginning, electric motors were more reliable than the competing drives.
In the beginning a central motor per factory floor was installed. With long transmission shafts, the rotational energy was distributed among the individual machines. The (sometimes several meters long ) transmission belt was dropped or placed usually at speed shaft. Here it came to accidents. The further development made it possible for each machine got its own electric motor. The transmissions disappeared in a short time. Was rapidly followed by a specialization for special machines (eg mills ) or hazardous areas. The number of electric motors per the machine or system grew steadily. Mass production made the electric motor cost.
Currently, one can observe that the electric motor is assigned not only the driving task, but also the reliable positioning of (usually linear ) machine movements. This servo- motors are used with the respective control units. Together with the new concepts for controlling and automating a machine you can watch a stormy technical development here.
World Record
2008 achieved a new world record, researchers of the ETH Zurich developed in cooperation with German companies, engine manufacturers ATE GmbH and bearing manufacturers myonic GmbH, an electric drive system with 1 million revolutions per minute. This is so far the highest speed which ever achieved by an electrical drive system.