The difference between motor and brushless motors

From now in general use in the industry,there are two main types of motor:efficient rare earth permanent magnet has a motor and the efficient rare earth permanent magnet brushless motor on the market at present most Electric bicycle is still stay in brush motor stage.A brush motor using mechanical commutation,the technical requirements of the control system is low,relative cost is lower than the brushless motor,A brush motor starting torque slightly larger than the brushless motor. But the fatal weakness is:life is short,large noise and low efficiency.Long-term use of carbon brush wear serious,it is easy to damage.At the same time wear produced huge amounts of carbon dust,These dust fall in gear oil,gear oil accelerate dries up,the motor noise further increased.A brush motor use to within a year or so will need to replace carbon brush,You will find a charge mileage bought less than two-thirds,and climbing when power is insufficient,will burn out the controller.This is because the motor After the replacement of carbon brush and commutator also be ground out a groove,reduce carbon brush contact area,poor contact of carbon brush after electrify which sparks and accelerate oxidation in electricalmotor1.blogspot.com To implement and copper,acmotortrading.blogspot.com lead to the undesirable phenomenon. Brushless motor electronic commutation replace the mechanical commutation,technically superior to brush motor.

Because of brushless motor without gear or gear,the motor,reduce wear and tear The unreliability.Its efficiency within a certain range of current ratio has a brush motor with high efficiency.Brushless motor driving up almost no motor lamination noise,and for up to 10 years to life On.According to the comparison,both brushless motor is better than have a brush.At present,there have been some electric bicycle factory with motor is to switch to the original brushless electric Machine.Brushless motor must be the development direction of electric bicycle. Consumers can come up from appearance to identify motor belongs to "brush" or "no brush" :first,"brushless electric wire" eight root,and the "brush" electric wire to the positive and negative There are two root;Secondly,with the induction motor hand when the drive motor,before and after the brushless motor rotation is easy,and before the "brush" motors turn easily,after when transfer is quite tight.

Torque or flux linkage control method

In t.g.Habetler no beat of direct torque control method,because of the large amount of calculation

and is not easy to achieve,therefore developed a series of simplified no beat directly Ac motor -

South Korea SPG ac motor series Ac motor - South Korea SPG ac acmotortrading.blogspot.com motor series Torque control,typically torque tracking prediction method.In this method,the paper analyzes the low speed torque ripple,torque ripple sawtooth asymmetric conclusions. Non-zero voltage vectors and the function of zero voltage vector rotating torque change is different,the former can make torque increase or decrease,while the latter is always decreased torque.In addition,in different speed range of the two counter rotating torque effect produced by the rate is changing.In torque predictive control method,the voltage vector in space position is fixed,the synthesis in the middle of the two single voltage vector,but the voltage vector is not effect the whole sampling period,but there is a certain duty cycle,in a sampling period can be divided into non zero voltage vector and zero voltage vectors.If the next sampling period of zero voltage vector and zero voltage vector to produce torque changes calculated torque error is equal to the three phase induction motor price cycle. To eliminate the torque error,achieve the goal of no beat torque control.Even appear calculated voltage vector effect time beyond the sampling period,also the full voltage vector can be used gasoline generator spare parts in place of,so it is very easy to implement,from the point of the experimental results,the torque ripple of the sawtooth basically symmetrical and explain the torque pulsation has been greatly reduced.Flux method considered by accurate control or change slowly,without considering the magnetic chain of beat control,in the literature on the flux and predictive control.

Summary of hybrid linear stepping motor technology

Basic step motor is composed of www.dongfeng-motor.com magnetic rotor iron core

through the stator with pulsation produced by the stator interaction between electromagnetic field

and produce rotation.Linear motor rotation movement into linear motion,to complete the transformation of precision depends on the step Angle of the rotor and the selected method.Linear stepper motor,or called linear stepper motor,first appeared in 1968 Patent no.3402308,was awarded to William Henschke.Since wholesalemotor.blogspot.com then,linear stepper motor is applied to

include manufacturing,precision alignment and precision of flow measurement,high demand areas.Use

thread precision of three-phase asynchronous motor,depending on the pitch.Install a nut in the center of the linear motor rotor,accordingly Use a screw nut with the mesh,in order to make the screw axial movement,must in some way to prevent the screw rotation with rotor components.Constrained due to the screw rotation,when the water pump motor rotor rotates,screw for linear motion.Both inside the motor with fixed screw shaft components and on the external thread shaft use can't rotate but axial freely Mobile nut,is a typical method of rotational restraint.To simplify the design,inside the motor to realize linear transformation is meaningful.The method greatly simplifies the design and make in many application fields in the motor lamination case of not to install the

external mechanical linkage directly using the linear motor for precision linear movement.The initial

linear motor has adopted A combination of a ball nut and screw.Ball screw to improve the efficiency

of above 90%,and according to thread condition,the efficiency of the trapezoidal thread with only 20%

to 20%.Although to convert rotary motion to linear motion ball screw is a kind of efficient

method,but the ball nut to calibration requirement is very high,and large,expensive.As a result, In

most applications,the ball screw is not a practical solution.