An electric motor in the modern world in itself is not something new for a long time. However, now this unit has become very popular. And primarily due to the active development of electric vehicles. Increasingly, there are discussions about the advantages and disadvantages of electric motors, is it worth taking an electric car or not, etc. This article will consider the features of electric motors, their varieties, advantages, and disadvantages, as well as prospects for further distribution.
Design features and principle of operation
The operation of any electric motor is based on the principle of electromagnetic induction. The main purpose of an electric motor is to convert electrical energy into mechanical energy. This transformation is carried out through the interaction of two main parts of the electric motor - the stator (stationary part) and the rotor (moving part). After power is applied, the magnetic field generated in the stator acts on the rotor, as a result of which the latter begins to rotate, from where the torque is generated.
Varieties and classification
Many different electric motors differ in design, principle of operation, and characteristics. All of them can be classified as follows.
- collector (the presence of a brush-collector unit):
- with permanent magnets;
- with series excitation (series stator winding);
- with parallel excitation (the stator and armature windings are connected in parallel);
- with independent excitation (the stator winding is powered from an independent current source);
- with mixed excitation (parallel and mixed connection is used).
- brushless or brushless.
- synchronous (rotor and stator rotate synchronously);
- asynchronous (rotor and stator rotate asynchronously):
The DC motor for an electric vehicle is the first and most affordable electric motor option. In this case, as a rule, a brushless motor for an electric vehicle is used. More modern and more expensive - asynchronous motors.
Additional Information. Using an induction motor for an electric vehicle is one of the key decisions of Tesla engineers. As a result, the powerful engine of Tesla's electric car became the key to the dynamism of these electric cars, which, in many respects, ensured the choice of consumers.
Features of synchronous and asynchronous motors
Synchronous motors are characterized by the following features.
- constant rotation speed;
- high efficiency;
- small reactive component;
- the ability to work with overload.
- high price;
- complex construction;
- complex launch system;
- the need for a constant voltage source;
- the complexity of the adjustment.
Asynchronous motors are characterized by the following points.
- simple start-up scheme (directly to the mains);
- admissibility of overloads (but short-term);
- the ability to receive high engine power;
- uncomplicated design;
- fairly simple maintenance;
- low cost.
- limiting the limiting rotation speed (cannot exceed 3000 rpm);
- high starting currents;
- the difficulty of adjusting the speed.
Classification of electric vehicles by type of electric motor use
Hybrids (Hybrids Electric Vehicle or HEV) are the first steps in building an electric vehicle. Such a car can hardly be called an electric car in the full sense of the word since the internal combustion engine (gasoline or diesel engine) in them still acted as the main unit. Whereas the electric motor played a secondary role and was charged from the energy of the internal combustion engine. Accordingly, the power reserve of such an electric motor was very small. Although a more capacious battery was installed on later models of hybrids, the sale of such cars was not in great demand. The reason was a complex and rather expensive system to maintain.
Plug-in hybrids (Plug-in Hybrid Electric Vehicle or PHEV) also had both an internal combustion engine and an electric motor, but they already provided for the ability to charge the battery from a regular household outlet. Thanks to the increased power of the battery, the range of the plug-in hybrid on the electric motor could reach 80 km.
A Range-Extended Electric Vehicle (REEV) is an electric vehicle that also uses two engines, but the electrical installation is the main one and the internal combustion engine is secondary. In such machines, the internal combustion engine is used only to generate energy for the electric motor. This design, on the one hand, saves fuel when using an electric motor, and on the other hand, it easily solves the problem of limited mileage, since gas stations can be found almost everywhere.
A classic electric vehicle (Battery Electric Vehicle or BEV) is a car that is driven exclusively by the energy generated by an electric power plant. Environmentally (or almost environmentally friendly) transport, which is currently gaining its popularity. Electric motor charging is possible at specialized electric filling stations, from a household outlet or mobile stations.
Fuel Cell Electric Vehicle (FCEV). As the name implies, the source of energy for the electric motor is not a battery, but a fuel cell (compressed hydrogen).
The motor-wheel or in other words the motor-wheel is a complex system that consists of the following units: a wheel, an electric motor, a power train. A braking system can also be used additionally. For the first time, the concept of such a device appeared back in 1884. Such a system is powered by a battery (on hybrids - from the internal combustion engine). In this case, the electric motor has two operating modes - traction (driving the wheel in motion) and generator (in fact, it is a recuperation system, in which braking energy is used to charge the battery).
Such a system is often used on electric bicycles, hoverboards, electric scooters, etc. Recently, attention has been paid to it in the automotive industry, due to its following advantages:
- lack of a large amount of equipment;
- excellent dynamics;
- simplification of the recuperation system;
- the ability to use both in engines with internal combustion engines and in electric cars.
Advantages and disadvantages of electric motors
The advantages of electric motors include the following:
- high efficiency (approximately 90-95%);
- absence of transmission friction losses;
- maximum torque immediately at the start;
- low operating costs;
- environmental friendliness;
- the simplicity of design;
- the possibility of engine braking;
- lack of a gearbox;
- low noise level.
The disadvantages of such engines include:
- time-limited work offline;
- the need for a power source (batteries, charging stations);
- long charging time.
Note. It is these problems that are holding back the widespread adoption of electric vehicles so far. And if the issue with the charging time has already been partially resolved (stations that support the fast charging standard have appeared), then the problem with a limited mileage resource per charge remains relevant.
Prospects for the development of electric motors
Speaking about the prospects of electric motors, it is worth noting the fact that today a lot of devices, both household and industrial, have an electric motor. The advent of electric vehicles gave a new impetus to the development of the electric motor.
Important. Nowadays, research is constantly being carried out, the purpose of which is to make the engine for an electric car better: to increase the power and operational characteristics, improve the efficiency, extend the service life, and optimize the device of the electric car engine. A popular and extremely important thing - improving the environmental situation in the world - will also contribute to the fact that the engine for an electric car will continue to develop because it is much more environmentally friendly than a car with an internal combustion engine.
Thus, it is safe to say that the electric motor was, is, and will be. At least until some completely new type of engine is invented.