Suppliers of frequency converter supporting equipment remind you that there are universal frequency converters and vector frequency converters for frequency converters. However, both types of frequency converters can be used, but they are still different. Friends can take a look at the analysis below to understand why vector inverters are priced higher than regular inverters.
There are two differences between vector frequency converters and ordinary frequency converters. It has high control accuracy, and secondly, it has a large low-speed output torque. It can output a torque of 150% -200% of the rated torque. Vector variation is the decomposition of motor current into D-axis current and O-axis current. The D-axis current is the excitation current, and the axis current is the torque current. By separating and controlling d and 0, the motor can obtain greater starting torque. Applied to on-site stations for starting heavy loads. For example, high-power long belts, elevators, etc. At this point, if a regular frequency converter is selected, if the load is too heavy during startup, the output torque is insufficient, and the motor cannot start, it will report faults such as motor blockage or frequency converter overcurrent.
The control of ordinary pumps can be done with blower pump type or ordinary type. No need to choose vectors, the price is very high. Regarding parameter settings, they are all quite similar. There's no difference.
For example, vector control is also known as velocity control. ”From the literal meaning, some differences can be seen
V/F control mode: It is equivalent to keeping the throttle of the foot unchanged while driving, and the speed is definitely changing at this time! The road that cars travel on is uneven, so the resistance of the road is also changing. If you go uphill, the speed will slow down, but if you go downhill, the speed will increase, right? For the frequency converter, your frequency setting corresponds to the throttle dog when driving, and the throttle dog when controlling V/F is fixed.
Vector control method: It can maintain the vehicle speed constant and improve speed control accuracy based on changes in road conditions, resistance, uphill, downhill, and other factors. So, regardless of uphill, downhill, or changes in road resistance, in order to maintain the same speed, the throttle opening must be adjusted at all times. Is that so? Just now I said: the speed setting value is equivalent to the throttle opening, and the setting value has not changed. How does the accelerator dog change and adjust to the road resistance at any time?
In fact, if the control method is chosen as vector control, the CPU inside the inverter will activate this special function! By providing feedback on changes in motor current and using a fixed program formula within the CPU, the internal PID controller can increase or decrease the opening and closing of some accelerators (engine inflow) based on the existing accelerator opening.
Therefore, on the surface, the accelerator opening degree does not change with V/F control and vector control, but in reality, the accelerator opening degree does not change with V/F control, and the actual accelerator opening degree changes with vector control (adjusted up and down according to the original accelerator opening degree). This is the only way to keep the vehicle speed as constant as possible.