The special dry type transformer, rectifier transformer and reactor, which are customized for the frequency converter system, are mainly used in the rectifier unit and inverter unit inside the inverter. The products are used in the standard general type frequency converter, the medium voltage converter and the high voltage inverter in the engineering drive.
Frequency converter（Variable-frequencyDrive，VFD）It is the application of frequency conversion technology and microelectronics technology to control the power control equipment of AC motor by changing the frequency of motor power supply. The converter is mainly composed of rectifier (AC variable DC), filter, inverter (DC AC), brake unit, drive unit, detection unit micro processing unit and so on. The frequency converter adjusts the voltage and frequency of the output power by the opening of the internal IGBT. According to the actual needs of the motor, the voltage of the power supply is provided to achieve the purpose of energy saving and speed regulation. In addition, the frequency converter has many protection functions, such as over current, overvoltage, overload protection and so on. With the continuous improvement of industrial automation, frequency converters have also been widely applied.
Frequency converters are usually divided into4Part: rectifier unit, high capacity capacitor, inverter and controller.。
The rectifier unit &emsp: converts the alternating current with fixed working frequency to direct current.。
High capacity capacitance: storage of converted electric energy。
Inverter : the power switch transistor array constitutes an electronic switch, converting DC to square wave with different frequencies, widths and amplitudes.
The controller: according to the set program, the amplitude and pulse width of the output square wave are controlled, and the alternating current superimposed to the approximate sine wave is driven and the AC motor is driven.
Appropriate voltage regulation measures should be adopted, such as series compensation, transformer installed with on load voltage regulating device, installing synchronous phase adjusting camera or electrostatic capacitor.
