Stepper motor step and step, the problems and solutions

 Synchronous torque generated in step motor cannot make the rotor speed single phase motor price with the rotation speed of the stator magnetic field, causing loss of steps. Step out the main reason and solution: (1) the stepper motor torque, drag the ability is not enough, when the drive pulse frequency reaches a critical value began to step out. Due to dynamic output torque of stepping motor with the continuous rise in frequency and reduce, so any working frequency is higher than the frequency will produce out of step. There are three solutions: can make the electromagnetic torque of stepping motor to produce increased, therefore can within the scope of rated current and appropriate increase the drive current. Torque is insufficient in the high frequency range, appropriate to improve the driving voltage of the drive circuit, To switch to large torque of stepping motor, etc., also can make the stepping motor to overcome torque decreases, and therefore can be appropriately reduce the frequency of motor operation, in order to improve the output torque of the motor. 

(2) step motor starting out of step. Because the stepping motor itself and the inertia load, when the accelerating time is too short will appear this phenomenon. Should set up reasonable acceleration time, make motor steady rise from low speed to a certain speed. (3) stepping motor to produce resonance is also a cause of out of step. The continuous operation of the stepping motor, if the control pulse frequency ac motor is equal to the natural frequency of the stepper motor, will produce resonance. In a control pulse cycle, vibration attenuation, has not yet been fully under a pulse has come, and so near the resonance frequency of dynamic error small diesel generator and leads to stepper motor out of step. The solution: reduce the stepper motor drive current. By adopting the method of subdivided driving and damping method. Rotor get too much energy in the process of step by step, the average speed of the rotor would be higher than the average rotational speed of the stator magnetic field, caused the stepper motor output torque increases, thus make the stepping motor produces more step. The step is when the stepper motor, the stepper motor can be reduced with the drive current, in order to reduce the output torque www.dongfeng-motor.com of stepping motor or make deceleration time longer.

Research on the positioning control of asynchronous motor - fuzzy controller

 (1) to determine the fuzzy controller input variables and output variables (2) design control rules of fuzzy controller (3) establish the blurred with the fuzzy method (4) select the fuzzy controller input variable and output variable in the theory field and determine the parameters of the fuzzy controller (quantitative factor and scaling factor) (5) the preparation of the application of fuzzy control algorithm (6) the rational selection of sampling time fuzzy control algorithm electric vehicle motor Generally use a two-dimensional fuzzy controller to the change of the error and error as input variables, to control the change of the quantity of output. The design of the fuzzy control rules generally includes: choose the word set of input/output variables, define a fuzzy variable fuzzy subsets and establish the control rules of fuzzy controller. The word set input and output variables, as a general rule, be {NB, NM, NS, NO, PO, PS, PM, PB}. Fuzzy variables of the fuzzy subset is to determine the shape of membership function of fuzzy ac electric motor subset. General use normal distribution. Control rules available conditional statements describe, that is, If A and B, Then C, Then control rules table is established. 


Blur is the accurate quantity into fuzzy quantity, can use formula: Y = 12 X (a + b) / 2 / (b - a) accurate quantity is the actual range [a, b]. The output of the fuzzy control is a fuzzy quantity, it cannot directly control the controlled object, needs to be converted into precise volume. There are three methods: (1) selection of maximum membership degree method. The method is simple, less but the use of information; (2) take the median method; (3) the weighted average decision method, the use of information, but the large amount of calculation. Controller of the control algorithm can be written as if E = A (I) then EC = B (j) then U = C (ij) (I = 1, 2, 3,... m; j = 1, 2, 3,..., n) based on the sampling error, error change, can calculate the corresponding control quantity changes, to all the X, Y all the elements in the entire portfolio to calculate the corresponding control quantity change, U can be written as matrix (ij) (n * m) will be made table electricalmotor1.blogspot.com matrix, as A lookup table, to be stored in memory. After the real-time control, based on the fuzzy quantitative error value and error changes of look-up table directly, then set the scaling factor can be as the output to control the controlled object.