Discrete space vector modulation method

No beat the direct torque control theory can maximize the elimination of torque and flux linkage

error,overcame the weakness with a Bang-Bang control inaccuracy,but need a larger amount of

calculation,and these are related to motor parameters,easy to cause the error in

calculation.Therefore proposed in the literature does not need much calculation,and can improve the torque and flux linkage control accuracy of discrete space vector modulation method.In the discrete space vector modulation method,and through the six basic two level inverter output voltage vector of the adjacent voltage vector and zero voltage vector for the synthesis of regular,as shown in figure 3 is the use of the adjacent single vector 2 and the single vector and zero voltage vector synthesized space voltage vector.Can be seen from the figure 3 its synthesis method is to put the average sampling period is divided into three segments,each segment is composed of non-zero voltage vectors or zero voltage vectors,such as space voltage vector z is 23 by the vector 2 and 3,a third and zero voltage vector of each sampling period can use five stages or 7 sections of mode synthesis (didn't),using the regular synthesis method can create 10 total voltage vector.acmotortrading.blogspot.com Elaboration of the voltage vector can be more accurate counter rotating torque and flux linkage control,in the literature on level 2 of flux using the traditional hysteresis Bang-Bang control,and turn into account Ac motor-South Korea SPG induction motor small motor series Ac motor-South Korea SPG induction motor small motor series Moment need fast dynamic response,the division of the level 5 hysteresis Bang-Bang control,as shown in figure 4,the error of different belt use different voltage vector table.

In addition,the author through the influence of voltage vector rotating torque change was derived formula is as follows: Can be seen from the type of ⑽ the same voltage vector in the influence of low stator winding machinespeed and high speed counter rotating torque changes are different.Therefore,in the different speed range with different voltage vector,as shown in figure 3.On the other hand,low speed using small amplitude of voltage vector and high speed using the amplitude of voltage vector is also in line with the V/f = C this rule.The traditional direct torque control in the low speed of continuous use more zero voltage vector switch frequency is very low,large torque ripple.According to the method of discrete space vector modulation due to the low speed using small amplitude of voltage vector,so the continuous use of zero voltage vector is little,high switch frequency,small torque ripple.In addition,due to the high speed of voltage vector is more,can be divided into 12 sectors,using two voltage vector table,it can be for more precise control.Can be seen from the above analysis,the discrete space vector modulation method is easy to implement,don't need any beat control as much as I would like to calculate,keep the traditional Bang-Bang control,the advantages of good robustness,therefore,but compared with the traditional direct torque control and can increase the torque and flux linkage control accuracy,reduce the torque ripple at low speed.But more to generator rotor and stator improve control accuracy and vector is divided into the thinner,the greater the voltage vector control table is more,this will increase the complexity of the control.So,if can let the discrete space vector modulation with no beat control,which will help you to overcome this shortcoming.