דק מאָטער פלאַנדזש מאָונטעד מאָטאָרס פונדרויסנדיק ראָוטער מאָטאָר מאַניאַפאַקטשערערז ינדיאַ
AC servo motor and DC servo motor
DC servo motor: the DC motor and encoder form a closed-loop control. The motor changes the torque, speed and other parameters of the motor by changing the size of the electricity. The structure of DC servo motor is similar to that of ordinary DC motor, except that the DC motor adopts slender armature, disk or hollow cup, or is changed into permanent magnet motor to meet the low inertia, which is the most ideal speed regulation system, which leads to the DC servo motor is relatively easy to realize speed regulation and high control accuracy. The disadvantage is that the DC servo motor has carbon brush, which is easy to cause motor wear, and the maintenance cost is high and the operation is troublesome.
AC servo motor: it is a kind of AC motor. It controls the torque, speed, position, etc. of the motor through the vector control theory of the servo driver. The rotor resistance of the AC servo motor is generally large, which can prevent rotation. When the control voltage disappears, there will be pulsating magnetomotive force in the AC servo motor due to the excitation voltage. AC servo is a synchronous motor with encoder, The effect is slightly worse than DC servo, but it is convenient to maintain. The disadvantage is that the price is high and the accuracy is not as good as that of DC! It is recommended to use AC servo motor. DC servo motor is too hot, with poor control accuracy and short service life.
Compared with DC servo motor, permanent magnet AC servo motor has the following main advantages: ⑴ it has no brush and commutator, so it works reliably and has low requirements for maintenance. ⑵ the stator winding is convenient for heat dissipation. ⑶ small inertia, easy to improve the rapidity of the system bellows coupling. (4) it is suitable for high-speed and large torque working state. (5) small volume and weight under the same power.
8、 Stepper motor
The magnetoelectric stepping motor has the advantages of simple structure, high reliability, low price and wide application, mainly including permanent magnet type, reluctance type and hybrid type.
(1) Permanent magnet stepping motor. The rotor has magnetic poles of permanent magnets, which generate alternating polarity magnetic fields in the air gap. The stator is composed of four phase windings. When phase a winding is energized, the rotor will turn to the direction of the magnetic field determined by the phase winding. When phase A is powered off and phase B winding is energized and excited, a new magnetic field direction will be generated. At this time, the rotor will rotate by an angle and be located in the new magnetic field direction. The sequence of the excited phases determines the rotor rotation direction. If the stator excitation changes too fast, the rotor will not be consistent with the change of stator magnetic field direction, and the rotor will be out of step. The low starting frequency and running frequency is a disadvantage of the permanent magnet stepping motor. But the permanent magnet stepping motor consumes less power and has higher efficiency.
דק מאָטער פלאַנדזש מאָונטעד מאָטאָרס פונדרויסנדיק ראָוטער מאָטאָר מאַניאַפאַקטשערערז ינדיאַ
2) Reluctance stepping motor. The inner and outer surfaces of the stator and rotor cores are provided with similar slots distributed according to a certain law. The change of the relative position of the slots of the stator and rotor cores causes the change of the magnetic resistance of the magnetic circuit, thus generating torque. The rotor core is made of silicon steel sheets or soft magnetic materials. When a phase of the stator is excited, the rotor will turn to the position where the magnetic resistance of the magnetic circuit is minimized. When the other phase is excited, the rotor turns to another position to minimize the magnetic resistance of the magnetic circuit, and the motor stops rotating. At this time, the rotor turns a step angle. There are many structural forms of reluctance stepping motor. The step angle of the reluctance stepping motor can reach 1 ° ~ 15 °, or even smaller, the accuracy is easy to ensure, the starting and running frequency is high, but the power consumption is large and the efficiency is low.
(3) Hybrid stepping motor. Its stator and rotor core structure is similar to that of reluctance stepping motor. The rotor has a permanent magnet that generates a unipolar magnetic field in the air gap, which is also modulated by the slots of soft magnetic materials on the rotor. Hybrid stepping motor has the advantages of both permanent magnet stepping motor and reluctance stepping motor. The motor has small step angle, high precision, high working frequency, low power consumption and high efficiency.
הויפּט פֿעיִקייטן
1. Generally, the accuracy of the stepping motor is 3-5% of the stepping angle and does not accumulate.
2. The maximum allowable temperature of the stepper motor surface. The maximum allowable temperature of the motor surface shall depend on the demagnetization point of different motor magnetic materials. The stepping motor surface temperature is completely normal at 80-90 ℃.
3. The torque of the stepping motor will decrease with the increase of the speed. When the stepping motor rotates, the inductance of each phase winding of the motor will form a reverse electromotive force; The higher the frequency, the greater the reverse electromotive force. Under its action, the phase current of the motor decreases with the increase of frequency (or speed), resulting in the decrease of torque.
4. The stepper motor can operate normally at low speed, but it cannot be started if it is higher than a certain speed, accompanied by howling. The stepping motor has a technical parameter: no-load starting frequency, that is, the pulse frequency at which the stepping motor can start normally under no-load condition. If the pulse frequency is higher than this value, the motor cannot start normally, and step loss or locked rotor may occur. Under load, the starting frequency should be lower. If the motor is to rotate at a high speed, the pulse frequency should have an acceleration process, that is, the starting frequency is low, and then it will rise to the desired high frequency according to a certain acceleration (the motor speed will rise from low speed to high speed).
דק מאָטער פלאַנדזש מאָונטעד מאָטאָרס פונדרויסנדיק ראָוטער מאָטאָר מאַניאַפאַקטשערערז ינדיאַ
9、 Electric motor for electric vehicle:
1. Motor for electric vehicle:
From the perspective of mature motor technology, switched reluctance motor seems to be more in line with the use needs of electric vehicles in various technical characteristics, but it has not been popularized. Permanent magnet synchronous motors are widely used, such as Kia K5 hybrid, Roewe E50, Tengshi, BAIC eu260, etc. Tesla Model X and model s adopt asynchronous motors. In addition, if divided by current type, it can also be divided into DC motor and AC motor.
DC motor: the technology of this kind of motor is relatively mature. It has the characteristics of easy control mode and excellent speed regulation. It has been widely used in the field of speed regulation motor. However, due to the complex mechanical structure of DC motor, its instantaneous overload capacity and the further improvement of motor speed are limited, and in the case of long-time operation, the mechanical structure of the motor will produce losses and increase the maintenance cost. In addition, when the motor is running, the spark from the brush will heat the rotor, which will cause high-frequency electromagnetic interference and affect the performance of other electrical appliances of the whole vehicle. Because DC motor has the above shortcomings, the current electric vehicles have basically eliminated DC motor.
Asynchronous motor: compared with permanent magnet synchronous motor, asynchronous motor has the advantages of low cost, simple process, reliable and durable operation, convenient maintenance, and can tolerate large changes in working temperature. On the contrary, a large temperature change will damage the permanent magnet synchronous motor. Although the asynchronous motor does not have an advantage in terms of weight and volume, its speed range is wide and its peak speed is up to about 20000rpm. Even if it does not match the two-stage differential, it can meet the speed requirements of high-speed cruise of this class of vehicles. As for the impact of weight on endurance mileage, the 18650 battery with high energy density can "Mask" the disadvantage of motor weight. In addition, the excellent stability of asynchronous motor is also an important reason for Tesla's selection.
Permanent magnet synchronous motor: permanent magnet synchronous motor is the most widely used motor in the field of new energy vehicles. The so-called permanent magnet refers to adding permanent magnet when manufacturing motor rotor. The so-called synchronization means that the speed of the rotor is always consistent with the current frequency of the stator winding. By controlling the input current frequency of the stator winding of the motor, the speed of the electric vehicle will be finally controlled. Compared with other types of motors, permanent magnet synchronous motors can provide maximum power output and acceleration for new energy vehicles. This is also the main reason why permanent magnet synchronous motor is the first choice of automobile manufacturers. However, permanent magnet synchronous motor also has its own shortcomings. The permanent magnet material on the rotor will produce the phenomenon of magnetic decay under the conditions of high temperature, vibration and overcurrent, so the motor is easy to be damaged under relatively complex working conditions. And the price of permanent magnet material is high, so the cost of the whole motor and its control system is high.
דק מאָטער פלאַנדזש מאָונטעד מאָטאָרס פונדרויסנדיק ראָוטער מאָטאָר מאַניאַפאַקטשערערז ינדיאַ
Switched reluctance motor: as a new type of motor, compared with other types of drive motors, switched reluctance motor has many advantages, such as simple and solid structure, high reliability, light weight, low cost, high efficiency, low temperature rise, easy maintenance and so on. Moreover, it has the excellent characteristics of good controllability of DC speed regulation system, and is suitable for harsh environments. It is very suitable for use as the driving motor of electric vehicles. It has been predicted by experts as a dark horse in the field of electric vehicles. However, the design of the control system is relatively complex, especially in the research and development stage, it is difficult to establish an accurate mathematical model for it with the existing technology. In the actual operation process, the noise and vibration emitted by the motor itself cannot be tolerated by the electric vehicle, especially under the load operation condition. To sum up, such motors may be widely used in the field of electric vehicles on the premise that they can overcome fatal injuries through technical optimization in the future, which can help improve the endurance mileage of electric vehicles.
Hub motor: up to now, it is still in the conceptual stage. One of the reasons hindering its development is that the hub motor brings too much burden on the unsprung quality.
Motor for electric vehicle:
Permanent magnet motor is divided into two categories: brush motor and brushless motor.
Brush motor: the carbon brush and commutator are used for mechanical commutation. Generally, the brush of brush motor should be replaced after about 2000 hours of wear. Ordinary hub motors and column motors (also called mid mounted motors) can only be replaced by professional maintenance personnel, while ordinary users of series excitation motors can replace them themselves. The wear of the brush is also related to the current and the silver content of the brush. The series motor used by the three freight wheels has a large current, and its service life is less than 2000 hours. It has to be replaced in a few months. The price of the carbon brush containing silver varies greatly. There are only two external wires for the brush motor, and the rotation direction can be changed by exchanging wires for the permanent magnet brush motor; Series excited motor has no permanent magnet. Both rotor and stator are windings. The stator magnetic field is also called excitation magnetic field. Each winding is independent. When used in series, it is called series excited motor. Although the series motor is also two external wires, commutation can be realized by exchanging one pair of rotor winding (a pair of wires) or stator winding (a pair of wires). Although the advantages of the brush motor cause trouble, the technology is mature, the accessories are easy to buy, and the supporting brush speed controller (hereinafter referred to as the brush controller) is cheap; The disadvantage is that after the brush is severely worn, the motor cover needs to be opened for replacement.
דק מאָטער פלאַנדזש מאָונטעד מאָטאָרס פונדרויסנדיק ראָוטער מאָטאָר מאַניאַפאַקטשערערז ינדיאַ
Brushless motor: electronic commutation is completed by the controller based on Hall element induction signal. There is no brush inside the brushless motor, and the winding current conversion is carried out by the external brushless speed controller (hereinafter referred to as the brushless controller). However, the brushless motor must provide the rotor position for the brushless controller. The common brushless motor has 8 leads, of which three are thick yellow, thick green and thick blue, which are winding leads, and the other 5 thin wires are rotor position sensor leads. Fine red is generally positive 5V, fine black is the 5V negative pole and signal common terminal, and fine yellow, fine green and fine blue are the three rotor position signal leads. Brushless controllers change the direction of winding current by the signals they provide. There are two types of brushless motors for electric vehicles: 60 degrees and 120 degrees, which can not be seen from the appearance. The brushless controller can also be divided into 60 degrees and 120 degrees. The motor and controller must be matched. There are only two kinds of correct wiring for 60 degrees, one is forward rotation and the other is reverse rotation; There are 6 types of correct wiring for 120 degrees, 3 types of forward rotation and 3 types of reverse rotation. The results of mismatched degrees or incorrect wiring are: no rotation, weak rotation, vibration, light load current, etc. Serious damage may occur to the controller or hall rotor position sensor inside the motor. The brushless motor does not have the problem of opening the cover to replace the brush, which theoretically saves power compared with the brush motor, and the subjective feeling is powerful; The disadvantage is that the price of the supporting brushless controller is much higher than that of the brush, and the failure rate is also high. The price of brushless controller has been greatly reduced and the quality has been improved. More and more electric bicycles and motorcycles have adopted brushless motor, which has a great momentum to replace the dominant position of brush motor. However, most maintenance workers are troubled by maintenance problems. Compared with the traditional brushless DC motor, the brushless DC motor has the following advantages: long service life, maintenance free, high reliability, high efficiency and energy saving.
Generally speaking, brush without teeth, brushless without teeth, brush with teeth and brushless with teeth refer to the presence of gears inside the hub motor. With the same power, the motor with teeth is more powerful than that without teeth when starting and climbing, which is suitable for the road conditions with slopes, and the high-speed motor has high efficiency. However, the service life of this kind of motor is low, and the accessories are difficult to buy, and the maintenance cost is high.
