The core vfd drive working principle is to convert the power frequency into an adjustable output frequency and change the speed of the motor by changing the frequency. The variable frequency drive achieves frequency regulation by converting the input AC power into DC power and then converting the DC power into adjustable AC power. This article will introduce the variable frequency drive working principle from AC-DC-AC vfd working principle and AC-AC vfd working principle.
AC-DC-AC vfd drive working principle
AC-DC-AC Variable frequency drive uses a circuit to first converter the industrial frequency power supply into a DC power supply, and then convert the DC power supply into an AC power supply with variable frequency, and then provide it to the motor, and change the frequency of the motor by adjusting the frequency of the output power supply. Rotating speed.
The industrial frequency AC power is converted into pulsating DC power by the rectifier circuit. The DC power is filtered and smoothed by the intermediate circuit and then sent to the inverter circuit. At the same time, the control system will generate drive pulses, which are amplified by the drive circuit and sent to the inverter circuit. , under the control of the driving pulse, the inverter circuit converts the direct current into alternating current with variable frequency and sends it to the motor to drive the motor to run. Changing the frequency of the AC output from the inverter circuit will cause corresponding changes in the motor speed.
The rectifier circuit, intermediate circuit, and inverter circuit constitute the main circuit of the Variable frequency drive, which is used to complete the “AC-DC-AC” conversion.
The control circuit is the control center of the inverter. When it receives the command signal from the input adjustment device or communication interface, it will send out the corresponding control signal to control the main circuit, so that the main circuit works according to the set requirements and at the same time controls the circuit’s Relevant settings and machine status information will also be sent to the display device to display relevant information to facilitate the user’s operation or understanding of the working condition of the inverter.
The display device of the Variable frequency drive generally uses a display screen and indicator lights; the input adjustment device mainly includes buttons, switches, knobs, etc.; the communication interface is used to communicate with other devices (such as a programmable controller PLC) and receive information sent by them, and also feedback information about the Variable frequency drive to these devices.
AC-AC vfd drive working principle
AC-AC vfd drive working principle
The AC-AC Variable frequency drive uses a circuit to directly convert the industrial frequency power supply into a variable frequency AC power supply and supplies it to the motor. It changes the speed of the motor by adjusting the frequency of the output power supply. The AC-AC Variable frequency drive is different from that of the AC-AC-AC inverter. It uses an AC-AC frequency conversion circuit to directly convert the industrial frequency power into an adjustable frequency AC power supply for frequency conversion speed regulation.
AC-AC Variable frequency drive generally can only reduce the input AC frequency to the output, and the frequency of the power supply is inherently low, so the speed regulation range of the AC-AC Variable frequency drive is very narrow. In addition, this type of Variable frequency drive requires a large number of use of thermistors and other power electronic devices has resulted in the large size and high cost of the device. Therefore, the use of the AC-AC Variable frequency drive is far less widespread than that of The AC-DC-AC Variable frequency drive. In conclusion, the electrical VFD drive working principle is similar in general while different types of VFDs may have a little difference in working principle. To know more, please contact us via info@sell-best.com.
