变频器基本组成
Basic composition of frequency converter
变频器通常分为4部分：整流单元、高容量电容、逆变器和控制器。
Frequency converters are usually divided into 4 parts: rectifier unit, high capacitance capacitor, inverter and controller.
整流单元：将工作频率固定的交流电转换为直流电。
Rectifier unit: converts the alternating current with fixed frequency to direct current.
高容量电容：存储转换后的电能。
High capacity capacitance: storage of converted electric energy.
逆变器：由大功率开关晶体管阵列组成电子开关，将直流电转化成不同频率、宽度、幅度的方波。
Inverter: an electronic switch composed of high-power switching transistor arrays, converting DC to square wave with different frequencies, widths and amplitudes.
控制器：按设定的程序工作，控制输出方波的幅度与脉宽，使叠加为近似正弦波的交流电，驱动交流电动机。
Controller: according to the set procedure, control the amplitude and pulse width of the output square wave, so that the alternating current is superimposed into sine wave, driving AC motor.