With the rapid development of modern power electronic technology and computer control technology, the technological revolution of electric drive has been promoted. Ac speed control instead of DC speed control, computer digital control instead of analog control has become a development trend. Ac motor frequency conversion speed regulation is a main means to save energy, improve production process, improve product quality, and improve the operating environment. Variable frequency speed regulation with its high efficiency, high power factor, as well as excellent speed regulation and braking performance and many other advantages is considered the most promising speed regulation.
The previous high-voltage inverter , composed of thyristor rectifier, thyristor inverter and other devices, has many shortcomings, large harmonics, and has an impact on the power grid and the motor. In recent years, some new devices have been developed that will change this situation, such as IGBT, IGCT, SGCT and so on. The high voltage inverter composed of them has excellent performance and can realize PWM inverter and even PWM rectification. Not only the harmonics are small, but also the power factor is greatly improved
Ac frequency conversion speed regulation technology is a combination of strong and weak electricity, mechanical and electrical integration technology, not only to deal with the conversion of huge power (rectification, inverter), but also to deal with the collection of information, transformation and transmission, so it must be divided into power and control two parts. The former should solve the technical problems related to high voltage and high current, and the latter should solve the software and hardware control problems. Therefore, the future high voltage frequency conversion speed regulation technology will also be developed in these two aspects, its main performance is:
(1) The high voltage variable frequency will develop in the direction of high power, miniaturization and lightweight.
(2) The high voltage variable frequency drive will develop in two directions: direct device high voltage and multiple superposition (device series and unit series).
(3) New power semiconductor devices with higher voltage and higher current will be applied in high voltage variable frequency drive
(3) At this stage, IGBT, IGCT, SGCT will still play a major role, SCR, GTO will exit the inverter market.
(4) The application of vector control, flux control and direct torque control technology without speed sensor will become mature.
(5) Fully realize digitalization and automation: parameter self-setting technology; Process self-optimization technology; Fault self-diagnosis technology.
(6) The application of 32-bit MCU, DSP and ASIC devices, to achieve high precision and multi-function inverter.
(7) Related supporting industries are moving toward specialization and large-scale development, and the social division of labor will be more obvious.
Post time: Oct-30-2023