The structure, main classification and application fields of frequency converter

The frequency converter is an electric power control device that uses frequency conversion technology and microelectronics technology to control AC motors by changing the frequency of the motor's working power supply.

The structure of the inverter

The structure of the inverter generally includes the following components:

1. Rectifier: Converts AC power into DC power, usually using a three-phase full-wave rectifier circuit.

2. Filter: Use capacitors, inductors and other components to filter out harmonics and noise in DC power to make the output voltage more stable.

3. Inverter: Converts DC power into AC power. Various circuit structures can be used, such as single-phase full-bridge, three-phase bridge, etc.

4. Control circuit: By controlling the switch tube of the inverter, the output voltage is adjusted and the output frequency and voltage of the inverter are controlled.

5. Protection circuit: including overcurrent protection, overvoltage protection, undervoltage protection, overload protection, etc., which can protect the inverter and the motor used and other equipment.

6. Display components: Usually use displays such as LED or LCD to display operating status, parameters and other information.

7. Radiator: A certain amount of heat will be generated inside the inverter, and the radiator can dissipate the heat to maintain the normal operation of the equipment.

The above is the commonly used structure of frequency converters. In fact, the structure of frequency converters of different types and manufacturers may be different.

Main categories of inverters

1. Classification by application field:

Industrial inverter: mainly used in mechanical equipment, automated production lines, etc. in industrial production;

Commercial inverter: suitable for commercial buildings, high-speed elevators, water pumps and other equipment.

2. Classification by output power:

Low power inverter: output power below 1kW;

Medium power inverter: output power between 1kW and 100kW;

High power inverter: output power is above 100kW.

3. Classification by control method:

Vector control inverter: can achieve high-performance control with relatively high accuracy and response speed;

Hardware control inverter: suitable for controlling machines running under load such as national research and heavy load, with high control accuracy and relatively slow response speed;

Software-controlled inverter: uses digital signal processing methods for control, which can achieve more flexible control strategies.

4. Classification by frequency control method:

Open-loop control inverter: using traditional PWM modulation method;

Closed-loop control inverter: Adds a feedback link based on open-loop control to achieve more accurate control.

In short, frequency converters are widely used and have many different classification methods. Choosing the corresponding frequency converter according to different needs can better meet the actual needs of users.

Application areas of frequency converters

The inverter is a power electronic device that can convert the frequency and voltage of the power supply into the output frequency and voltage that meet the requirements. The use of inverters varies according to different application fields, and is mainly used in the following fields:

1. Industrial automation production line: The frequency converter can adjust the speed of the motor, thereby realizing the control and management of the production line and improving production efficiency.

2. Water pump and fan control: By adjusting the speed of water pump and fan through the frequency converter, energy consumption cost can be reduced and efficiency can be improved.

3. Transportation: Inverters can be used in electric vehicles, elevators, rail transit and other fields to improve transportation efficiency and comfort and reduce energy consumption and noise.

4. Cooling and air-conditioning systems: The inverter can adjust the compressor speed of the air-conditioning and cooling systems, thereby achieving precise control and energy-saving operation.

5. Metallurgy, chemical industry and other industrial fields: The inverter can control high-power motors to achieve functions such as frequency regulation and current balance, thereby improving equipment reliability and efficiency.

6. New energy field: The application of inverters in the fields of solar energy, wind energy, etc. is becoming more and more extensive, making the use of these new energy sources more efficient and reliable.