In order to realize variable speed operation of motor, inverter technology is widely used in explosion-proof motor. As a device, the inverter can convert the power frequency power supply (50Hz or 60Hz) into a variety of frequency AC power supply, so as to achieve the variable speed operation of the motor. The device includes a control circuit for controlling the main circuit; Rectifier circuit for converting alternating current to direct current; The DC intermediate circuit is used to smooth and filter the output of the rectifier circuit; Inverter circuit, used to convert direct current into alternating current. In some frequency converters that need to perform a lot of operations, it is also necessary to be equipped with a CPU for torque calculation and the corresponding circuit. By changing the power supply frequency of the stator winding of the motor, variable frequency speed regulation can realize the purpose of speed regulation.
Inverter According to different classification methods, can be divided into voltage type inverter and current type inverter, PAM control inverter, PWM control inverter and high carrier frequency PWM control inverter, V/f control inverter, slip frequency control inverter and vector control inverter, General inverter, high performance special inverter, high frequency inverter, single phase inverter and three phase inverter, etc.
In the frequency converter, VVVF refers to changing voltage and frequency, while CVCF refers to constant voltage and constant frequency. In the AC power supply used in countries around the world, whether in homes or factories, the voltage and frequency are usually 400V/50Hz or 200V/60Hz(50Hz). The device that converts such a power supply into a voltage or frequency variable AC power supply is called a "frequency converter". In order to generate variable voltages and frequencies, the device first needs to convert alternating current to direct current (DC).
The frequency converter is used to control the motor and can change both the voltage and the frequency. According to the speed expression of the AC motor, the speed n is proportional to the frequency f, and the speed of the motor can be adjusted as long as the frequency f is changed. Therefore, the frequency converter realizes speed regulation by changing the motor power supply frequency, which is a high efficiency and high performance speed regulation means.
In the development of frequency converters, a variety of control methods have evolved, including:
Sinusoidal pulse width modulation (SPWM) control mode, where 1U/f=C;
Voltage space vector (SVPWM) control mode;
Vector control (VC) mode;
Direct torque control (DTC) mode;
Matrix intersection - intersection control mode, etc.
Above, the innovative application of inverter in explosion-proof motor is described. Through inverter technology, the speed of the motor can be adjusted flexibly, bringing high efficiency and high performance power solutions to the industrial field.
Post time: Aug-26-2023
