CNC vertical lathe spindle control two kinds of commonly used speed control scheme
CNC vertical lathe spindle control device of two commonly used control solution release date: 2016 - 09 - 12 clicks: 2691 nc vertical lathe spindle control, main spindle motor speed control mode, control of motor speed change how the way, the following instructions nc vertical lathe spindle control device of two commonly used control schemes: one, ac speed regulation in ac electric variant voltage variable frequency speed regulation system is equipped with the static type of the variable voltage variable frequency is mainly composed of the main circuit and control circuit of two parts. For asynchronous motor is used in the industrial production of the inverter can be divided into pay & ndash; Straight & ndash; The alternating voltage source SPWM inverter and pay & ndash; Straight & ndash; Two of the alternating current source type SPWM inverter, at most, the most widely used in industrial inverter is & ndash; Straight & ndash; The alternating voltage source SPWM inverter. The main circuit with uncontrolled rectifier, with SPWM inverter, the output voltage waveform is close to sine wave. The intermediate dc link inverter main circuit is adopted the capacitor filter. The adoption of SPWM control, so that the output voltage waveform is close to sine wave type. Voltage source type variable voltage variable frequency speed regulation system has two main circuit power transform link form, and the bridge rectifier and inverter bridge, diode rectifier bridge is made of three-phase bridge uncontrolled circuit. Regulation and frequency modulation through the inverter to complete, the given value is derived from the same for a given segment. The SPWM control technique is used to implement variable voltage variable frequency control system, by changing the duty ratio (IGBT Pulse width) To control the size of the ac voltage inverter output, so as to change the motor speed. The output frequency by controlling the inverter bridge working cycle can be achieved. Ac speed regulation, low price, easy maintenance, low maintenance cost. Ac frequency conversion speed adjustment, has been rapid development of the scope of its application is more and more widely. Second, dc speed adjustment along with the rapid development of computer technology, digital control system in gradually replace the old analog control system. With full digital dc speed regulating device of a microcomputer, without changing the hardware, or changes in a few cases, depending on software support, you can easily achieve a variety of regulation and control function, so the general flexibility and reliability of the application of full digital dc speed regulating device is obviously superior to analog control system. At present, with Germany's SIEMENS 6 ra70 series general full digital dc speed regulating device is used most widely in China. Dc motor speed control does not need to other devices, but by changing the input voltage/current, or excitation voltage/current to speed. Dc speed regulating device USES Germany SIEMENS 6 ra70 dc speed regulating device to control dc motor speed regulation, and speed control mode is divided into changed the armature terminal voltage control of motor speed and flux control. Dc motor using his way excitation excitation. Dc motor of the voltage balance equation for U = Ea + RIa ( 1) Type of U for the power supply voltage, the unit V. R is the armature circuit the total resistance, the unit & Omega. 。 By the voltage balance equation and the induced electromotive force formula, can get the speed of the dc motor features n = have Ia = U - electromagnetic torque equation 廖内省, RIa=Keφ CeTem into speed characteristic equation, i. e. , by mechanical characteristic equation KTφ UR- TemCeCeCtn=（ 2) By the voltage balance equation ( 1) Know ( 3) Ua = U - type RadIa for armature terminal voltage. When Ia = 0 or Rad = 0, Ua = U by type ( 3) And Ea = Cen electromotive force formula, available n = Ua - speed formula RaIa（ 4) CeEa=U- ( Ra＋Rad) Ia=（ U - RadIa） - RaIa=Ua- RaIa according to speed formula ( 4) , change the armature terminal voltage control is to keep the flux & phi; Constant, change the motor armature voltage U, the ideal no-load rotation speed n changes with the armature voltage, and the mechanical properties and the slope remain unchanged; Unchanged magnetic flux control is to keep the armature voltage U, weakening magnetic general principles of the ideal no-load rotation speed increases with the decrease of n as the flux of the, also increase the mechanical properties of the slope.