What is the role of the frequency converter
Inverter is a kind of electrical equipment that converts industrial frequency power into AC power of any frequency and voltage. Inverter has the function of adjusting the motor speed and realizing environmental protection and energy saving. The use of inverter is mainly to adjust the power of the motor and realize the speed change of the motor. run. The composition of the frequency converter mainly includes two parts: the control circuit and the main circuit. The main circuit also includes components such as rectifier and inverter. The following are the details of the function of the frequency converter:
1. Frequency conversion energy saving
The energy saving of the frequency converter is mainly manifested in the application of fans and water pumps. In order to ensure the reliability of production, all kinds of production machinery have a certain margin when they are designed and equipped with power drives. When the motor cannot run under full load, in addition to meeting the power drive requirements, the excess torque increases the consumption of active power and causes a waste of electrical energy. The traditional speed adjustment method of fans, pumps and other equipment is to adjust the air supply and water supply by adjusting the inlet or outlet baffle and valve opening. The input power is large, and a large amount of energy is consumed in the interception process of the baffle and valve. middle. When using frequency conversion speed regulation, if the flow requirement is reduced, the requirement can be met by reducing the speed of the pump or fan.
The function of the motor using the frequency converter is to adjust the speed and reduce the starting current. In order to generate variable voltage and frequency, the device first converts the AC power of the power supply into direct current (DC). This process is called rectification. A device that converts direct current (DC) into alternating current (AC), its scientific term is "inverter" (inverter). Generally, the inverter converts the DC power supply into a certain fixed frequency and certain voltage inverter power supply. For inverters with adjustable frequency and adjustable voltage, we call them inverters. The waveform output by the frequency converter is an analog sine wave, which is mainly used for speed regulation of three-phase asynchronous motors, also called variable frequency speed regulators. For the variable frequency inverters, which are mainly used in the detection equipment of instruments and meters, which require higher waveforms, the waveforms must be sorted and can output a standard sine wave, which is called a variable frequency power supply. The general frequency conversion power supply is 15-20 times the price of the frequency converter. Since the main device that produces the variable voltage or frequency in the inverter equipment is called "inverter", the product itself is named "inverter", namely: inverter.
Frequency conversion can not save electricity everywhere, and there are many occasions that using frequency conversion may not save electricity. As an electronic circuit, the inverter itself also consumes power (about 3-5% of the rated power). A 1.5-hp air conditioner itself consumes 20-30W of electricity, which is equivalent to a permanent beacon. It is a fact that the inverter runs under the power frequency and has the power-saving function. But his prerequisite is:
First, high power and fan/pump load;
Second, the device itself has a power saving function (software support);
Third, long-term continuous operation.
These are the three conditions that reflect the power-saving effect. In addition, it doesn't matter whether saving electricity or not, it has no meaning. Without preconditions to say that the inverter is energy-saving in industrial frequency operation, it is an exaggeration or commercial hype. Knowing the whole story, you will cleverly use it to serve you. It is necessary to pay attention to the use occasion and conditions of use in order to apply it correctly, otherwise it will be blindly obedient, credulous and "deceived".
2. Power factor compensation and energy saving
Reactive power not only increases the line loss and heat generation of the equipment, but more importantly, the reduction of the power factor leads to the reduction of the active power of the grid. A large amount of reactive power is consumed in the line, the equipment is inefficient and the waste is serious. Use a variable frequency speed control device Later, due to the effect of the internal filter capacitor of the inverter, the reactive power loss is reduced and the active power of the power grid is increased.
3. Soft start energy saving
The hard start of the motor will cause a serious impact on the power grid, and it will also require too much power grid capacity. The large current generated during startup and vibration will cause great damage to the baffle and valve, which is extremely detrimental to the service life of equipment and pipelines. After using the frequency conversion energy-saving device, the use of the soft start function of the frequency converter will make the starting current start from zero, and the maximum value does not exceed the rated current, which reduces the impact on the power grid and the requirements for power supply capacity, and extends the use of equipment and valves. life. Save equipment maintenance costs.
In theory, the frequency converter can be used in all mechanical equipment with motors. When the motor is started, the current will be 5-6 times higher than the rated current, which will not only affect the service life of the motor, but also consume more electricity. When the system is designed, there will be a certain margin in the selection of the motor. The speed of the motor is fixed, but in the actual use process, sometimes it needs to run at a lower or higher speed, so it is very important to carry out frequency conversion transformation. Necessary. The frequency converter can realize the soft start of the motor, compensate the power factor, achieve the purpose of energy saving and speed regulation by changing the input voltage frequency of the equipment, and can provide the equipment with protection functions such as overcurrent, voltage, and overload.
To sum up, the role of the frequency converter includes:
1. It can reduce the impact on the grid, and it will not cause the problem of excessive peak-valley difference.
2. The acceleration function can be controlled, so as to smoothly accelerate according to the needs of users;
3. The stopping method of the motor and equipment is controllable, making the entire equipment and system safer, and the service life will increase accordingly;
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