I believe that we have been in contact with the frequency converter, and many friends have used it. There are two kinds of frequency converters: general frequency converter and vector frequency converter. Although both of them can be used, there are differences between them. After reading the analysis below, we can understand why the price of vector converter is higher than that of general inverter.

There are two main differences between vector converter and ordinary frequency converter. The first is high control precision, the second is low speed output torque. It can output 150% - 200% of rated torque. Vector frequency conversion is to decompose the motor current into d-axis current and q-axis current, where d-axis current is excitation current and q-axis current is torque current. By controlling D and Q separately, the motor can get more starting torque. It is generally used in heavy load startup. Such as high-power long belt, and elevator and so on. At this time, due to the load is too heavy and the output torque is not enough, the motor can not be started, and the motor stalling or inverter over-current and other faults are reported.

For the control of ordinary water pump, fan pump special type or general type can be selected, there is no need to select vector, the price is high. The parameter settings are similar. There's no major difference.

As we all know, vector control is also called "speed control". We can see the difference literally.

V / F control mode: just like when driving, the throttle opening of your foot is unchanged, and the speed of the car must be changing! Because the road the car is on is uneven, and the resistance of the road is also changing. The speed will slow down when going uphill, and it will speed up when going downhill, right? For the frequency converter, your frequency setting value is equivalent to the opening of the accelerator on your foot when driving, and the throttle opening is fixed when v / F is controlled.

Vector control mode: it can control the change of road conditions, resistance changes, uphill, downhill and other changes of the car, try to keep the speed constant and improve the speed control accuracy. So, if you want to keep the speed stable regardless of uphill, downhill and road resistance changes, the throttle opening must be adjusted at any time, right! Just said: the speed setting value is equivalent to the throttle opening. If the setting value does not change, how does the throttle opening change and adjust it in place at any time according to the road resistance?

In fact, when you choose "vector control" as the control mode, the CPU inside the inverter will open this special function! Using the information fed back from the motor current change, through the program and formula solidified in the CPU, and through the PID regulator inside the CPU, continuously increase or decrease some throttle opening (engine oil intake) on the basis of your original throttle opening.

So, on the surface, your throttle opening does not change under V / F control and vector control, but in fact, it does not change in V / F control, while in vector control, the actual throttle opening is changed (adjust up and down on the basis of your original throttle opening). In this way, the speed can be kept as constant as possible.