天津电动伸缩门知名厂

变频器主要是由主电路、控制电路组成。

The frequency converter is mainly composed of the main circuit and the control circuit.

主电路是给异步电动机提供调压调频电源的电力变换部分，变频器的主电路大体上可分为两类:电压型是将电压源的直流变换为交流的变频器，直流回路的滤波是电容。电流型是将电流源的直流变换为交流的变频器，其直流回路滤波是电感。 它由三部分构成，将工频电源变换为直流功率的“整流器”，吸收在变流器和逆变器产生的电压脉动的“平波回路”，以及将直流功率变换为交流功率的“逆变器”。

The main circuit is the power conversion part to provide the voltage regulating and frequency modulation power supply for the asynchronous motor. The main circuit of the frequency converter can be generally divided into two kinds: the voltage type is to transform the DC of the voltage source into the AC frequency converter, and the filter of the direct current loop is the capacitor. The current type is a converter that converts the current source to the AC, and its DC loop filter is an inductor. It consists of three parts: the rectifier which converts the power frequency power to the DC power, absorbs the "flat wave circuit" of the voltage ripple produced by the converter and inverter, and the "inverter" that converts the DC power to the AC power.

（1）整流器：最近大量使用的是二极管的变流器，它把工频电源变换为直流电源。也可用两组晶体管变流器构成可逆变流器，由于其功率方向可逆，可以进行再生运转。

(1) rectifier: the recent use of a diode converter, it transforms the power frequency power into a DC power supply. Two sets of transistor converters can also be used to form a reversible converter, which can be regenerated because of its reversible power direction.

（2）平波回路：在整流器整流后的直流电压中，含有电源6倍频率的脉动电压，此外逆变器产生的脉动电流也使直流电压变动。为了抑制电压波动，采用电感和电容吸收脉动电压（电流）。装置容量小时，如果电源和主电路构成器件有余量，可以省去电感采用简单的平波回路。

(2) flat wave circuit: after rectifier rectifier's DC voltage, it contains 6 times the frequency of the power supply, and the pulsating current generated by the inverter also changes the DC voltage. In order to suppress the voltage fluctuation, the inductor and capacitance are used to absorb the pulse voltage (current). When the device has a capacity of hour, if the power supply and the main circuit constitute the remainder, a simple flat wave circuit can be used to save the inductor.

（3）逆变器：同整流器相反，逆变器是将直流功率变换为所要求频率的交流功率，以所确定的时间使6个开关器件导通、关断就可以得到3相交流输出。以电压型PWM逆变器为例示出开关时间和电压波形。

(3) inverter: on the contrary with rectifier, the inverter converts the DC power to the required frequency AC power. At the specified time, the 3 phase AC output can be obtained by turning 6 switch devices on and off. The voltage type PWM inverter for example to show the switching time and voltage waveform.