The function and characteristics of frequency converter in coaxial line machine are introduced

Coaxial machine inverter is to put the power frequency power supply (50 hz or 60 hz) transform into various frequency ac power, so as to realize the variable speed motor running of equipment, including control circuit to complete the control of the main circuit, rectifier circuit to alternating current into direct current, dc intermediate circuit to smooth filtering of the output of the rectifier circuit, inverter circuit dc inverse again into alternating current.

For a frequency converter that requires a lot of computation, such as a vector control converter, a CPU for torque calculation and some corresponding circuits are sometimes required. Frequency conversion speed regulation is achieved by changing the frequency of power supply of motor stator winding.

The frequency conversion technology of coaxial line machine is based on the need of ac motor stepless speed regulation. Since the 1960 s, power electronics device has experienced the SCR (thyristor), decision (gate turn off thyristor), BJT) (bipolar power transistor, MOSFET (metal oxide field-effect tube), SIT (static induction transistor), by (static induction thyristor), MGT (MOS transistor control) and MCT (MOS controlled thyristor), IGBT (insulated gate bipolar transistor), HVIGBT high-pressure (insulated gate bipolar thyristor) in the development process, the device updates to promote the development of power electronic transformation technology.

Since the 1970s, the research on pwm-vvvvvf speed regulation has attracted great attention. In the 1980s, PWM mode optimization, as the core of frequency conversion technology, attracted people's keen interest and concluded many optimization modes, among which PWM mode with saddle wave was the best. Since the second half of 1980s, VVVVF inverters from developed countries such as the us, Japan, Germany and the UK have been put into the market and widely used.