Variable-frequency drive (VFD) is a 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 inverter is mainly composed of rectifier (AC to DC), filtering, inverter (DC to AC), braking unit, drive unit, detection unit, microprocessor unit, etc. The inverter relies on the interruption of the internal IGBT to adjust the voltage and frequency of the output power supply, and provides the required power supply voltage according to the actual needs of the motor, so as to achieve the purpose of energy saving and speed regulation. With the continuous improvement of industrial automation, frequency converters have also been widely used.
With the introduction of the development model of energy-saving and environmentally-friendly society, people have begun to pay more attention to the environmental quality of life. Energy-saving, low-noise inverter is a general trend of development in the future. Although there are many manufacturers of inverters in China, there is a lack of unified and specific specifications and standards, which makes the products quite different. And most of them use V f control and voltage vector control, which have low accuracy, low dynamic performance and poor stability performance, which has a certain gap compared with similar foreign products. As far as inverter equipment is concerned, its development trend is mainly manifested in the following aspects.
The inverter will develop in the direction of high voltage and high power and low voltage and low power, miniaturization and light weight.
Industrial high-voltage and high-power inverters, civil low-voltage and small-power inverters have great potential.
For now, IGBTs, IGCTs and SGCTs will continue to play a major role, and SCRs and GTO will exit the inverter market.
The application of technologies such as vector control, magnetic flux control and direct torque control without speed sensors will become mature.
Fully realize digitalization and automation, such as parameter self-setting technology, process self-optimization technology, and fault self-diagnosis technology.
The application of high-performance single-chip microcomputer optimizes the performance of the inverter and realizes the high precision and multi-function of the inverter.
Related supporting industries are developing towards specialization and scale, and the social division of labor is gradually obvious.
With the development of a conservation-oriented society, the use of inverters in the civilian field will be gradually promoted and applied.