Numerical control lathe with frequency converter principle and structure of explanation
Numerical control lathe with frequency converter principle and structure, a release date: 2017 - 09 - 05 clicks: 2918 times of frequency converter is used for numerical control lathe the on-off role of power semiconductor devices will power frequency power conversion to another frequency power control device, can realize the ac asynchronous motor soft start and frequency control of motor speed, improve the operation accuracy, change the power factor, over current/over voltage/overload protection, and other functions. Numerical control lathe with inverter working principle: the main circuit is to provide the asynchronous motor frequency modulation voltage regulator power conversion part of the power supply, the main circuit of frequency converter in general can be divided into two categories: voltage type is the dc voltage source transformation for ac frequency converter, dc loop filter is capacitance. Current mode is the current source dc transform for ac frequency converter, the dc loop filter is the inductance. It consists of three parts, the power frequency power transformation for dc power & other; Rectifier & throughout; To absorb in the converter and inverter voltage ripple & other Flat wave loop & throughout; , and the dc power conversion for ac power & other; Inverter & throughout; 。 1, recently a lot of using a diode rectifier converter, it convert power frequency power supply for dc power supply. Can also be used in the two groups transistor converter constitute a reversible converter, due to its reversible power direction, can be regenerated. After 2, smooth wave circuit in the rectifier rectifier dc voltage, contains 6 times the power frequency voltage ripple, and inverter and dc voltage pulse currents change. In order to suppress voltage fluctuation, the absorbing pulsation of the inductance and capacitance voltage ( Current) 。 Device capacity hours, if the power supply and main circuit devices have allowance, could save inductance based on simple flat wave circuit. 3, inverter and rectifier instead, dc power inverter is to transform for the required frequency ac power, to determine the time to make 6 switch device conduction, can get a 3 phase ac output shut off. With voltage source PWM inverter as an example shows the switch time and voltage waveform. Control circuit is for asynchronous motor power supply ( Adjustable voltage and frequency) Main circuit to provide control signal circuit, it has frequency, voltage & other Operation circuit & throughout; , and other main circuit; Voltage, current detection circuit & throughout; , motor & other; Speed detection circuit & throughout; , the operation circuit control signal amplification & other; Drive circuit & throughout; , as well as the inverter and motor & other; Protection circuit & throughout; Composition. ( 1) Operation circuit: the outside of the speed and torque command with the comparison of current and voltage signal detection circuit calculation, determine the inverter output voltage and frequency. ( 2) Voltage, current detection circuit, and the main circuit voltage isolation test voltage, current, etc. ( 3) Drive circuit, drive circuit of main circuit device. Its isolation makes the main circuit and control circuit device conduction, shut off. ( 4) Speed detection circuit: the loads on the shaft of the asynchronous motor speed detector ( Tg, PLG, etc. ) A signal for speed signal, into computing circuit, according to the instruction and operation speed operation can make the motor according to the instructions. ( 5) Protection circuit: detection of main circuit of voltage, current, etc. , when overload or overvoltage abnormal occurs, in order to prevent damage of inverter and asynchronous motor, the inverter stop working or suppress voltage and current value.