1。电动机工作的物理原理
1.1麦克斯韦的方程系统
电动机是一种换能器，可不断转换电磁能和机械能。
当输入电能时，电动机可以连续输出扭矩和机械能。
即电动机；相反，如果外力连续推动电动机轴并输入机械能，则电动机可以连续从电线端从电线端反向输出电能和电能，即发电机。
从历史上看，静态变压器也被算作电动机，但它逐渐演变为仅参考电动机和发电机。
One of the advantages of electric motors is that their losses are relatively small, so they achieve high efficiency.
Large electric motors can achieve efficiencies of up to 99%.
When talking about electromagnetic systems, Maxwell's system of equations is inevitable.
In the macroscopic world and even in the microscopic world,
Maxwell's system of equations can be used very effectively to describe the system properties.
Maxwell's system of equations has been summarized from previous studies of electromagnetic phenomena.
There are four very basic equations, both in differential and integral form.
Now let's examine Maxwell's system of equations in integral form.
The above two equations describe the flux of the field density, respectively, the total of the outflow potential shift picture and the total of the rotating magnetic field induction picture in a closed space surface
According to the knowledge learned in high school, the electric field can be generated by point charge excitation, the magnetic field can not be excited by the magnetic monopole, but to extend the path closed, so the electric field is active, the magnetic field is passive.
So the total potential shift flux is the total charge q and the total magnetic flux is 0.
The above two equations describe the spin quantities of the field intensity, the integrals of the total electric field intensity and the total magnetic field intensity.
Corresponding to the rate of change of the magnetic flux and the rate of change of the potential shift (current intensity), respectively, for one turn along the path of the curve on a closed space curve.
The Gauss and Stokes formulas also allow the rewriting of the above four equations into differential form as follows.
▽ for the Nabla operator, with vector dot product to calculate the scatter and fork product to calculate the spin, P for the charge body density, and Jn for the current density.
The above equations can describe basically all the electromagnetic behavior that occurs in all ac induction motor systems
1.2 Material polarization and magnetization for electrical energy
在施加的电旋转磁场中，材料分子将改变其方向，因为极性受到场强的影响。
原始布置的各种大小的分子基组形成的电域将由于施加的磁场而被极化，并且电荷分布方向会收敛。
E0 = 8.854187817*10-12F/m是真空介电常数，它也是真空介电常数，而P是相对介电常数，它取决于材料本身的性质。
（1.9）描述了施加的电场的潜在移位密度和相应的极化强度图片一起。
In an applied magnetic field, the corresponding magnetic domains and magnetization strengths can be obtained in the same way.
Unlike the electric field, a magnetic polarization strength M is introduced, which describes the difference between the magnetic induction strength of the material and that of the vacuum environment.
U0=4π*10-7 N.A-2 is the vacuum permeability and Ur is the relative permeability, which describes the ability of the material to allow a magnetic field to pass through.
If Ur<=1 is antimagnetic, the material prevents the passage of a magnetic field; if the image is paramagnetic, the material complies with the passage of a magnetic field.
If Ur>=1o 5 具有铁磁性，钴镍铁等材料磁化后会增强磁场。去除磁场后仍保留一定强度的磁场，称为剩磁。
电机运行过程中会不断地磁化和退磁，因此还应注意检查不同材料的磁滞线。
磁滞线描述了在强度为 H 的外加磁场作用下，磁性材料的磁感应强度随着场强的增加而增加。
这种磁感应强度在达到磁饱和后并不跟随磁场强度。
After the magnetic saturation is reached, it is difficult to follow the increase in field strength. When the external magnetic field strength slowly decreases to zero, it can be seen that the demagnetization curve still retains the remanent magnetization B when it passes the zero point.
This remanent magnetization shows the general principle of manufacturing permanent magnets, i.e., directional magnetization followed by gradual demagnetization. When the inverse magnetic field is applied, the magnetic induction strength goes to zero or even increases in the opposite direction, and this excess is called the coercivity H.
1.3 Electromagnetic force and mechanical energy
电动机的最大价值是实现电能转换为机械能，在外部工作并执行目标运动。
带电粒子在磁场中的运动受到垂直于运动方向的洛伦兹力的力，其宏观表达是安培力hm = il * b，可以通过使用左手规则来确定方向，，可以通过左手来判断。
I是磁场中导体在电流方向上的有效长度。
静电场Fe = QE中还有相应的电场力。
And both magnetic and electric fields are themselves fields, and the force applied to the charge or current element in them depends on the volume and field density, and thus the corresponding field force can be examined in terms of the field.
The above two equations still maintain the symmetry, the charge density P in a certain volume due to the electric field field field strength produces the electric force density fe = pE,
The current density J in a certain volume due to the magnetic field field strength produces the magnetic force density Fm = J * B (the above equation (1.12) must be used in the case of isotropic materials and constant current) .
This expression inspires us to directly examine the energy and energy density of the electromagnetic field.
In this way, the electromagnetic potential energy at a certain point can be determined by finding the gradient to obtain the corresponding electromagnetic force density and thus find the total electromagnetic force on the object under investigation.
1.4 Coil model
A coil is a fundamental element that forms a model of induction motors, bridging the circuit model of the ac motor and the physical model of the object.
A straight section of energized conductor generates a toroidal magnetic field around it (according to equation 1.4).
当导体在开始和末端关闭时，环形场在导体环的中心形成磁力线，该电路垂直通过导体环，例如电磁阀。
仅考虑电流导体上的电流，（1.4）简化为：
磁性力（磁性durchfluchtung）是激发场强度的来源，本质上是通过[a]中封闭导体部分的总电流的强度。
由于在实践中，通电的电线将被缠绕到线圈中，因此电流电流被离散化，并且（1.13）被重写为
n是线圈中的绕组总数，即转弯数。
It can be seen that if the number of turns is higher, the total current is higher, the magnetic potential is higher, and the stronger the magnetic field can be excited.
A single-turn coil in a time-varying magnetic field will induce a voltage at both ends of the wire, a phenomenon described by (1.3).
It can be understood that the magnetic induction can also be interpreted as the magnetic flux density, which can be obtained by substituting (1.3)
Ui is the induced electric potential, consider two forms of flux change, one is to change the coil area but change the flux density, then there are as follows;
前一部分是正式转化的诱导电位（转换诱导的电压），后者是翻译转换的诱导潜力（转化张力）。
前者具有时间变化的磁通量密度，而后者具有时间变化的有效线圈区域。
在高中物理学中提到了这种归纳原则，也称为长笛定理。
当线圈有多个转弯时，总有效通量正好是扩展的线圈转弯的整数倍数，从而引入了磁链的概念。
链条在下图中定义。
请注意，磁链是标量的数量，就像磁通量一样。由于电流本身的变化也可能导致通量变化，因此趋势是阻碍磁通变化，可以将其定义为：：
i是不同的电流强度，L是亨利[H]的自节感系数，其大小与线圈体积形状，转弯次数和磁渗透性有关。
使感应电动机的线圈在线圈中间具有铁磁物质，例如铁芯，以提高磁渗透性，因此线圈在铁芯上缠绕，因此名称为绕线。
对于一段线性均质材料，其自感系数可以用下式近似
自感是线圈自身电流变化而感应出抑制电压的现象，它对直流电动机的电流变化具有阻碍作用。
当两个线圈相互靠近时，除了自身的自感外，还因为相邻线圈上的电流变化而产生互感
具有线性恒等式的材料的互感系数由上式近似，可知互感同时受到两个线圈匝数的影响。
Ignoring the resistance and examining the self and mutual inductance of the two adjacent coils, the voltage equation can be listed from Figure 1.5 about dc motors
Since the coupling parts have the same material parameters and shape, the resulting mutual inductance coefficients are equal M12=M21.
So the size of the coupling chains on each coil is proportional to the current strength on the corresponding rotor windings coil for dc motor..
1.5 Ohm's theorem for electrical energy and magnetic circuits
In secondary school we studied Ohm's theorem, which states that the resistance of a conductor is the ratio of the voltage and current at both ends, and that there is a formula to describe the resistive material itself.
q，这是电导率，它正是电阻率P的倒数，并描述了导致电流的能力。
除了施加电阻外，电动机工作时也可以使用电导率图片来描述电压和电流之间的关系。
现在检查单位面积的电流强度，即电流密度j = i/a E（E是单位矢量），电流密度为矢量指向AC电机的电流方向。
这可以与电压方程U = E.L和（1.25）重写（1.26）合并为
上面的方程式描述了微观水平的欧姆定理，即，电流密度的变化对应于施加到导体上的恒定场强度。
Lm is the effective length of the magnetic flux through a section of the magnetic circuit, and A is the corresponding flux area.
The above equation is very similar to the resistance formula.
Let us deform the magnetoresistance formula again and we can continue to obtain
It can be seen that in units the magnetoresistance is actually the inverse of the inductance coefficient.
Continuing the analogy with the concept of conductance, we obtain the magnetic conductance A (magnetische Leitwert, in [H] or [Ωs])
In the circuit we find the differential elements for (1.26) and get the microscopic Ohm's theorem, so what is the microscopic Ohm's theorem corresponding to the magnetic circuit?
We can go on to rewrite equation (1.31), noting that the magnetic flux itself has a flux density B ,which then yields
So the microscopic magnetic circuit Ohm's theorem is equation (1.10), and the magnetic field strength under is the flux density obtained from the magnetization of a constant magnetic field.
The computational analysis of the reluctance can be used to realize a micro-element analysis of the flux in the entire motor winding pole, core part and intermediate air gap part, which can realize a discrete finite element analysis FEM (Finite-Elemente-Methode) of the entire magnetic circuit.
It is also possible to apply Kirchhoff's theorem for the circuit in the magnetic circuit, which is very intuitive and convenient.
欢迎在评论区与我们分享更多关于电机的资讯！
任何关于电机的咨询，请联系专业电机 制造商 在 中国 如下：
东淳电机拥有广泛的电机产品，应用于交通、基础设施、建筑等各个行业。
获得及时回复。
