When to use a common inverter When to use a vector inverter

Ordinary inverter:

It is suitable for occasions where the control accuracy is not high, mainly when the speed accuracy is not high. It can be used when one inverter drags multiple motors.

Vector inverter:

Suitable for high-performance general purpose applications. Such as machine tools, centrifuges, wire drawing machines, injection molding machines and other loads.

Ordinary inverter:

Most of them use diode rectifier bridges to convert AC power into DC, and then use IGBT inverter technology to convert DC into AC power with adjustable voltage and frequency to control AC motors. This kind of inverter can only work in the electric state, so it is called a two-quadrant inverter.

Since the two-quadrant inverter uses a diode rectifier bridge, it is impossible to achieve a bidirectional flow of energy, so there is no way to send the energy of the motor feedback system back to the grid. In some applications where the motor wants to feed back energy, such as elevators, hoists, centrifuge systems, pumping units, etc., only a resistance braking unit can be added to the two-quadrant inverter to consume the energy fed back by the motor. In addition, diode rectifier bridges can cause serious harmonic pollution to the power grid.

Vector inverter:

The technology is based on the theory of DQ axis, and its basic idea is to decompose the current of the motor into D-axis current and Q-axis current, where D-axis current is the excitation current and Q-axis current is the torque current, so that the excitation current and torque current of the AC motor can be controlled separately.

It is an ideal control theory designed for AC motors to make AC motors have similar control characteristics to DC motors, which greatly improves the control characteristics of AC motors. However, at present, this control theory is not only applied to AC asynchronous motors, but also to DC variable frequency motors (BLDC, that is, permanent magnet synchronous motors).

Vector and vector are a method or concept of vector (vector) analysis in mathematics, the two are the same concept, but the name is different, the simple definition refers to a quantity with both magnitude and direction.

Vector is our (mainland) statement, and the term vector is generally used in the literature of Hong Kong and Taiwan. The meaning is roughly the same as what "Bush" and "Bush" mean. Vector control is primarily a concept of decoupling of motor models.

What is the warranty period for vector drives?

How to set the carrier frequency of the inverter is the most scientific?

The inverter is rectified into DC by alternating current, and then using three bridges and six drive tubes to achieve three-phase output of different phases, which is equivalent to three-phase alternating current output, and then control the drive, the frequency of the pulse makes the output frequency change, and at the same time, the frequency of the rotating magnetic field of the asynchronous motor changes and obtains asynchronous speed regulation.

1. First carry out the no-load test operation of the inverter

First of all, check whether all the wiring of the inverter is correct, do not connect the output end of the inverter to the motor, and conduct a no-load test on the inverter first. Read the user manual of the inverter carefully before powering on, be familiar with the relevant functions, settings and operation methods, and power on this basis.

Check whether the signal and control action of the external terminal are normal, such as whether the output frequency of the inverter changes at the same time as the given signal when the potentiometer is rotated clockwise or the frequency is changed to a given current.

2. No-load test operation of the inverter with motor: After the no-load test operation of the inverter is normal, the motor can be connected to the no-load test run. Before connecting the motor, be sure to confirm that the technical indicators of the motor are qualified.

The motor should not be loaded. Then let the inverter drive the motor to rotate, and observe whether it is normal, such as whether the direction of rotation of the motor meets the requirements.

Turn the frequency given potentiometer counterclockwise to the left end 0Hz, then turn on the forward switch (FWD) of the frequency converter, slowly rotate the potentiometer clockwise, so that the given frequency gradually increases, observe the rotation of the motor, at 50% of the maximum frequency, let the motor rotate for a few minutes, and observe the value of voltage and current, and then let the output frequency of the frequency converter reach the maximum frequency, and then let the motor rotate for a few minutes.

3.Inverter load operation and commissioning: Before starting commissioning, check that there is no personnel around the load and that there are no foreign objects on the load before loading and commissioning.

4. Frequency setting: When debugging, first give a smaller frequency to observe whether the load runs smoothly and whether there is abnormal sound in operation. If there is, it is necessary to consider replacing the inverter and motor of the larger model in time to make the control current and torque within the range; In addition, according to the load characteristics, a reasonable acceleration and deceleration time is set to ensure that the inverter does not report overcurrent faults during operation and start-up.

According to the V f curve, the frequency rises and the overvoltage increases, and the motor is not rated voltage, which does not affect the operation of the motor.

Frequency modulation and voltage regulation are realized through PWM transient wave, and the motor is not rated voltage and frequency should be adjusted accordingly to ensure that the V F ratio is consistent.

The principle of frequency converter changing frequency:

1. The inverter is rectified into DC by alternating current, and then three bridges and six drive tubes are used to achieve three-phase output of different phases;

2. It is equivalent to three-phase alternating current output, and then the control drive, and the frequency of the pulse changes the output frequency;

3. The frequency of the rotating magnetic field of the asynchronous motor is changed to obtain the asynchronous speed regulation.

The role of the inverter:

1. The inverter can adjust the power of the motor and realize the variable speed operation of the motor, so as to achieve the purpose of saving electricity. Examples can be seen in centrifugal fans and pumps, where frequency converters are used for centrifugal fans and pumps, which allow the operator to control the flow easily as needed, thus saving energy.

2. The inverter can reduce the fluctuation of voltage in the power line, and avoid the phenomenon of tripping or abnormal operation of the equipment once the voltage is abnormal.

3. The inverter can reduce the impact on the power grid, thereby effectively reducing the reactive power loss and increasing the effective power of the power grid.

4. The inverter can also reduce the wear between the transmission parts in the machinery, therefore, it also reduces the cost to a certain extent and improves the stability of the system.

5. In addition, the control function is very complete, which can be well cooperated with other control equipment or together, so as to achieve centralized monitoring and real-time control, and solve a lot of problems such as system compatibility for users.

Differences: 1 low-frequency torque, the low-frequency torque characteristics of the vector inverter are very, the traditional V F inverter, below 5Hz, is difficult to output full torque, and the vector inverter can achieve 10 150% torque transmission posture when the vector inverter is in the state.

2. The control mode, vector inverter, can be more convenient to achieve closed-loop control, while V F inverter is much worse.

3**。The inverter of the same power, the ** of the vector inverter, is at least 20% higher than the V F inverter.

Vector control mode: It can control the car to keep the speed constant as much as possible under the condition of road condition changes, resistance changes, uphill and downhill changes, so as to improve the speed control accuracy. Then, if you want to keep the speed stable regardless of the uphill, downhill, and road resistance changes, the throttle opening must be adjusted at any time.

Vector inverter technology is based on the DQ axis theory, and its basic idea is to decompose the current of the motor into D-axis current and Q-axis current, where D

Vector inverter:

The shaft current is the excitation current, and the Q-axis current is the Hu Song torque current, so that the excitation current and torque current of the AC motor can be controlled separately, so that the AC motor has similar control characteristics to the DC motor, which is an ideal control theory designed for the AC motor, and greatly improves the control characteristics of the AC motor. However, at present, this control theory is not only applied to AC asynchronous motors, but also to DC variable frequency motors (BLDC, that is, permanent magnet synchronous motors).

Vector and vector are a method or concept of vector (vector) analysis in mathematics, the two are the same concept, but the name is different, the simple definition refers to the quantity bond purity with both size and direction.

Vector is our (mainland) statement, and the vector statement is generally used in the literature of Hong Kong and Taiwan. Meaning and"Bush"with"Bush"The meaning is roughly the same. Vector control is primarily a concept of decoupling of motor models.

In the electrical field, it is mainly used to analyze AC electricity, such as motor analysis, etc., and the application in the inverter is based on the theory of motor analysis for frequency conversion control, which is called vector control inverter, and the method of realization is not the only one, but the mathematical model is basically the same.