Inverter is an electrical device that converts power supply into AC power of any frequency and voltage. It is used to adjust the motor power and let the motor variable speed movement. The composition of the inverter mainly includes the control circuit and the main circuit. The main circuit also includes components such as rectifier and inverter.

The inverter working principle is to control the main circuit through control circuit. The rectifier in the main circuit converts the alternating current into direct current. The intermediate circuit of the direct current smoothes and filters the direct current. Finally the inverter converts the direct current into alternating current of the required frequency and voltage.  Some inverters will also add CPU and other components in the circuit to perform torque calculation.

The basic functions of inverter are as follows:

1.  Soft Start

The direct start of inverter motor will cause serious impact on the power grid. It is extremely detrimental to the service life of the equipment and power grid circuits. The speed regulation function (V/F) of the inverter will make the starting current from small to large. It strictly control the starting peak current, and the maximum normal working current will not be higher than the rated current. This reduce the impact on the power grid and prolonging the equipment life. The inverter can be used as a soft start, but the soft start cannot be used as an inverter, so the inverter is more expensive than the soft start.

2.  Speed Regulation

The speed regulation refers to the AC asynchronous motor. The motor speed is related to the frequency of the alternating current. Change frequency will change speed. So the inverter first converts the alternating current into direct current and then converts it into an alternating current that can be adjusted at 0-50HZ. So as to achieve the adjustment of the motor. The output voltage and current of the inverter become higher with the increase of frequency.

The power frequency of the inverter is generally 50Hz or 60Hz. Whether it is in the household field or the production field, the frequency and voltage are constant. The motor power will drop during speed regulation, but through the adjustment of the inverter, the motor can reduce power loss during speed regulation.

3.  Energy Saving

Why the inverter can save power and save energy? Because the inverter controls the speed of the motor. In fact, most speed control equipment can achieve this effect. So we cannot conclude that the inverter is an energy-saving product.

The premise of the inverter to save electricity is the speed regulation characteristics of its load. For spare parts whose speed has a great influence on power, such as centrifugal fans and centrifugal pumps, the adjustment effect of the inverter is obviously better than that after its own speed regulation operation. , the inverter can actually achieve the effect of energy saving and electricity saving under this premise.

If the spare part handled by the inverter is a constant torque load or even a constant power load, the power drop is not obvious or the power remains constant when the speed drops, so the use of the inverter cannot reach the same level as before. The effect of energy saving and power saving, or even can not save electricity at all.

Whether there is a big difference between the use efficiency of the frequency converter and the use efficiency of the digital DC governor, this question also needs to be considered in combination with the actual situation. Under certain conditions, the power of the DC motor is higher than that of the AC motor and the power factor higher, so AC asynchronous motors and variable frequency speed controllers are not more power efficient than DC motors and DC speed controllers.

4.  Strong Protection

Short-circuit protection to ground, phase-to-phase short-circuit protection, input phase loss protection, output phase loss protection, over voltage protection, under voltage protection, temperature protection Input and output reverse polarity protection. Over current, heat sink overheating, external alarm, inverter overheating, braking power, resistance overheating, motor overload, inverter overload, DC fuse open circuit, memory abnormality, keyboard panel communication abnormality, CPU abnormality, option abnormality , Forced stop, abnormal output circuit, abnormal charging circuit, abnormal RS485 communication.

5.  Increased Automation

The control function of the inverter is already very complete, and it can cooperate well with other control equipment and instruments to realize centralized real-time monitoring and control of systematic networking, such as with DCS, PLC, servo drives, etc., which greatly improves the automation of production line equipment degree.

There are many kinds of inverters, which can be divided into general inverters, high-performance special inverters, high-frequency inverters, single-phase inverters and three-phase inverters according to different uses. According to working principle, they can be divided into V/f control inverter, slip frequency control inverter and vector control inverter, etc. In the field of industrial automation, the role and status of the inverter are pivotal and indispensable.