| Because it has such a lot of advantages, such as efficiency, economic energy, economy etc. The technique of variable frequency speed regulation is now become a very important application technique in both agriculture and industry field, In each oil-field and mineral factory of our country, frequency conversion machine got the extensive application. But because of frequency conversion machine when it was in application it will produce harmonic interference inevitably, the traditional means can't be applied in variable frequency speed regulation system completely, therefore need some new analytical methods aiming at frequency conversion machine accordingly. In this text, around the specification of frequency conversion machine, proceed some study, has finished some work as below primarily:This text will study the output characteristic and the output characteristic of variable frequency speed regulation system. The input characteristic include power quadrangle theory, the relation of cos(?) ,η and f. Output characteristic include the relation of efficiency and discharge under 50Hz situation, and the relation of rated efficiency and discharge under the frequency conversion situation.According to traditional power triangle (the square of the active power, reactive power and apparent power form the relation of the right triangles), put forward a new electrician's theories of power quadrangle. Because of the influence of harmonic, traditional power triangle can't be applied in variable frequency speed regulation system, this text proof the accuracy of the power quadrangle.This text verify the linear regression relation of the power factor, efficiency and rated loading according to the spot data, and proof the linear regression relation is more accurate than other related relation.The large quantity statistics data express, the efficiency of motor is not accordant with the data that are marked in the data plate. According to known data, This text make use of the tool of MATLAB, apply regression method, put out the regression relation of them and verified the accuracy of this model.For different pump, the relationship of efficiency and discharge is indefinite, however through a certain conversion, for resembling pump, exist some kind of regulation that can be grasped by person, this text proceed the research of it.Moreover, this text discuss the calculation formula of the output power when motor is working at unrated circulation and how to realize excellent efficiency. |
