变频器英文.doc

Frequency changer In general inverter power electronic technology, micro computer technology and modern control theory developed based on intelligent electrical appliances. Its main function is to provide the variable frequency communication load of power. In recent years, inverter with excellent performance of speed adjustment and energy-saving ability in the field of electric power drag control won a wide range of applications. Here is a frequency converter to the relevant knowledge introduction. 1.Converter working principle (1)Overview Main circuit is provided for asynchronous motor power surge FM power, and the inverter transform part of main circuit substantially can be divided into two classes: the voltage type is the dc voltage source inverter, the transformation as dc circuit communicate the filtering is capacitance. Current model is to transform into the dc current source of converter, communicate the dc circuit filter is the inductance. It consists of three components, will work frequency power transformation for dc power rectifier, absorb the converter and inverter the resulting voltage ripple” flat wave loop ”and will transform into ac power dc power of inverter. (2)Rectifier Recently the extensive use of the diodes converter, it is the industrial frequency power transformation for dc power supply. Also used two groups of transistor converter constitute reversible, because its power converter, can undertake renewable direction reversible operation. (3)Flat wave loop After rectifying the rectifier of dc voltage, contains six times the power supply voltage ripple frequency, moreover inverter produces the current ripple also make dc voltage fluctuant. In order to restrain voltage fluctuation, using inductance and capacitance absorption voltage ripple (current). Device capacity hours, if the power and main circuit constitute devices have allowance, can save inductance using simple flat to wave circuits. (4)Inverter Contrary, inverter with rectifier is requi