CN1155188A

CN1155188A - Phase-serve-modulating device for quick precision lock

Info

Publication number: CN1155188A
Application number: CN 96100963
Authority: CN
Inventors: 阮树成
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-01-18
Filing date: 1996-01-18
Publication date: 1997-07-23
Anticipated expiration: 2016-01-18
Also published as: CN1056713C

Abstract

The present invention relates to a high-speed precision phase-locked servo tuner device, which comprises main phase discriminator output series phase-difference limiter, D/A converter and auxiliary quadrature phase discriminator output coherent AGC control and velocity feedback nonlinear control servoamp, and adopts a servomechanism in which VCO tuning capacitor is lineraly and synchronously connected with servo-actuator and velocity-measuring machine. When working, the phase-locked loop voltage-controlled oscillator VCO phase is quick locked, and the reference crystal oscillator phase is precisely and synchronously tracked, so that said invented product is applicable for high-frequency heating in industrial installation and agricultural production, locking phase and stabilizing frequency in ISM radio-frequency equipment and raising working efficiency, etc..

Description

A kind of phase-serve-modulating device for quick precision lock

The present invention relates to a kind of phase-locked servo tuner, particularly relate to a kind of phase-serve-modulating device for quick precision lock.

Industry high-frequency heating apparatus phase locking frequency stabilized is to heat the device VCO that shakes with the voltage-controlled servo-tuning of phase frequency detector detection of error signals Vd, and application number 92104322.8 Chinese patents disclose the technology of this equipment.Existing phase frequency detector is a Digital Logical Circuits, and operating mode changes detection beat voltage Vd=Vdm output, and voltage is maximum, and forward and reverse step voltage High-speed Control VCO frequency is tuning to reducing the frequency difference direction, has very wide off-resonance frequency and catches tractive effort.But, when frequency difference enters the phase bit comparison near zero state, Vd → 0, the output voltage trend is to zero, because phase discrimination signal porch triggering work, it is big to trigger noise.This noise is round the phase signal random fluctuation, and similar normal state distributes, and its pulsewidth and amplitude are uncertain.When loop tracks differs near φ=0 for a short time, because of being subjected to noise pollution, and because of the tuning inertia of frequency difference high speed, differ the zero-bit competition, detected signal errors is bigger, or the transmission of servo-tuning low speed is not steady, and its result influences the inhibition of VCO first-harmonic sideband interfering frequency radiation.Usually, it is quite short that workpiece adds the thermofussion welding time, duration only finishes in several seconds, power supply energy storage persistent wave is shorter heating time, require locking time fast, high accuracy steady track melting welding speed, yet, the noise that phase discriminator is introduced is superimposed upon on the phase potential difference, and loop filter does not have the ability of filtering to it.And loop filter is analog circuit, and integrating capacitor discharges and recharges lotus to square wave phase potential difference and can not respond rapidly, the voltage controlled frequency of VCD is difficult to accurately control proofreaies and correct.With the simple digital-to-analogue conversion of charge pump, additional noise is bigger.Because the servo electric tuning exists the unfavorable factors such as time-delay of gearing friction and inertia, Backlash Nonlinearity error, electro mechanic time constant all to influence stable state accuracy.Reduce loop gain, then influence lock speed etc., tuning being difficult to of single speed taken into account.These problems have nothing to do at electronic tuning, but voltage-controlled device is confined to low pressure small-power VGO work, and electromechanical servo tuning be not limited by oscillation source voltage, power.The linear tracking of existing simulation phase discriminator is low noise, but do not possess the frequency discrimination function, and operating mode changes just can't catch off-resonance frequency.

The present invention seeks to: improve phase-locked servo tuner wen-frequency characteristics, the phase place that makes voltage controlled oscillator VCO fast, high-precise synchronization follows the tracks of benchmark crystal oscillator phase place and a kind of phase-serve-modulating device for quick precision lock is provided.

The technology of the present invention solution is to export to be connected in series between the loop filter input at phase-locked servo tuner master phase discriminator to differ limiter, D/A converter, main phase discriminator input also connects the auxiliary relevant AGC automatic gain control of quadrature phase detector realization servo amplifier, and in servo amplifier introducing speed feedback control, servomechanism adopts the VCO tuning capacitor to be connected synchronously with servomotor, tachometer straight line.

Based on above-mentioned technical solution is the restriction of taking the phase difference signal shaping, special-purpose digital to analog converter improves noise characteristic, and improve the loop filter transient response, auxiliary quadrature phase detector extracts the relevant AGC control loop gain tuning of leading main phase discriminator pi/2 phase potential difference, the double speed variable bandwidth improves lock speed and precision, introducing the damping of speed feedback Nonlinear Dynamic proofreaies and correct, the steady transmission of the non-rigid contact of servo linear motor is tuning, further improve Phase synchronization speed and steady-state tracking precision, the requirement that reaches higher standard suppresses the radiation of fundamental frequency sideband interfering frequency, concentrates the base band energy.

Below in conjunction with drawings and Examples the present invention is described in detail.

Fig. 1 is a principle of the invention block diagram.

Fig. 2 is a servo-tuning structural scheme of mechanism of the present invention.

With reference to Fig. 1, a kind of phase-serve-modulating device for quick precision lock of Fig. 2, the output serial connection of main phase discriminator (3) differs limiter (4), D/A converter (5) is to the input of loop filter (6), quadrature phase detector (9) input is connected to the input of main phase discriminator (3), the input of its output termination smoothing filter (10), the input of tachometer (2) output access speed feedback controller (11), loop filter (6), the output of velocity feedback controller (11) all inserts the input of servo amplifier (7), smoothing filter (10) output connects the AGC control end of servo amplifier (7), the output of servo amplifier (7) connects servomotor (8), the moving plate pole plate of VCO tuning capacitor (2) places servomotor (8), on the axostylus axostyle of tachometer (2), and ground connection, the stator pole plate connects the resonant groove path of heating oscillator VCO.

Phase difference signal pulsewidth and amplitude through differing the output of limiter master phase discriminator are limited in a certain steady state value, suppress irregular at random noise pulse interference of moment and enter D/A converter.Digital to analog converter is that the electronic switch by binary code counting controlling resistance network solves corresponding weight voltage, converts analog quantity to by the amplifier summation.At this moment, loop filter has good transient response to analog signal, satisfies two requirements, and the one, filtering characteristic, the 2nd, proofread and correct transient error.Velocity feedback controller voltage-stabiliser tube and amplifier are rate signal and become the characteristic that the damping of resistance Nonlinear Dynamic is proofreaied and correct, and improve servo-tuning not only fast but also the excessive vibration of non-overshoot amount.

Before phase locking, the poor phase voltage direct current deal of quadrature phase detector output is very little, and the field effect transistor gate bias almost are zero, the pipe output resistance is big, the servo amplifier high-gain drives the tuning VCO of servomotor high speed, makes its loop that enough wide bandwidth be arranged, and acquisition phase is synchronous fast.When entering phase control, the phase difference signal of quadrature phase detector output is the pi/2 of the leading main phase discriminator output phase difference signal of phase shift, is added to servo amplifier AGC control end through smothing filtering, and the field effect transistor output resistance reduces.The main phase discriminator phase difference signal that feeds back to the servo amplifier input is strengthened, and the servo amplifier gain diminishes the tuning VCO of servomotor low speed.At this moment, loop bandwidth is narrow, has guaranteed the tracking steady-state behaviour.Quadrature phase detector and main phase discriminator differ 90 ° of relevant AGC controls, and time domain precision height is avoided the losing lock of tuning sudden change through smothing filtering.

In the time of phase capturing and tracking, speed feedback is proofreaied and correct the voltage control that obtains tachometer output opposite polarity, and the damping of servo linear motor inertia Nonlinear Dynamic has further improved the tuning dynamic accuracy of VCO.VCO tuning capacitor and servomotor, the synchronous servomechanism that is connected of tachometer straight line, no backlash error, stable drive, reaction speed is fast.

The embodiment of the invention 1, the phase-locked high frequency hot press of power output 2.5KW level, the frequency 40.680MHz that the first-harmonic centre frequency of heating oscillator VCO adopts 1EC/CISPR international standard regulation industry (ISM) radio-frequency apparatus to use allows frequency difference ± 0.05%.The phase-locked servo tuner adopts servomotor, tachometer, VCO tuning capacitor straight line to connect synchronously; Main and auxiliary phase discriminator adopts digital IC circuit, 8 D/A converters and control of relevant AGC automatic gain and speed feedback nonlinear Control.Any workpiece heating acquisition phase lock in time＜10ms, steady track is tuning steadily and be synchronized with workpiece melting welding speed, and the heat seal effect is improved.Actual measurement heating oscillator VCO work fundamental frequency allows that frequency difference reaches the IEC international standard.

The embodiment of the invention 2, nominal operation frequency 40.680MHz, the phase-locked ultrashort wave medical treatment of power output 500W machine, servomechanism adopts linear electric motors, tachometer, VCO tuning capacitor Trinity straight line to connect synchronously, main phase discriminator output serial connection differs limiter, D/A converter, loop filter to the servo amplifier drive motors, auxiliary quadrature phase detector output is through the relevant AGC control of smothing filtering servo amplifier, and simultaneously, the tachometer signal speed is fed back non-electrical control servo amplifier.Voltage controlled oscillator VCO output is placed on patient's affected part by electrode, VCO tuning capacity, resonant inductance and human body equivalent capacity series resonance, and when the tuning VCO of phase-locked control equaled the nominal operation frequency, patient's affected part equivalent capacity voltage was the highest, the heat maximum.Change the required suitable power of VCO input voltage regulation clinical treatment, actual measurement VCO fundamental frequency allows that frequency difference meets the IEC international standard, effectively suppresses the radiation of interfering frequency, and improves therapeutic efficiency.

The embodiment of the invention 3, the phase-locked HF induction heating apparatus of power output 100KW level, operating frequency 3.150MHz, adopt technical scheme phase-serve-modulating device for quick precision lock of the present invention, the quenching workpiece frequently and is discontinuously worked, the phase place fast precise is synchronous, the voltage controlled oscillator VCO high power valve remains on the operating state of not off resonance, power output and stabilised efficiency are greatly improved, anode dissipation power does not increase because of the workpiece equivalent load impedance changes, and is fixed on optimum state all the time, therefore not only improves the equipment heating function, suppress the radiation of interfering frequency, also increase the service life.

The present invention is reasonable in design, advanced technology, precision height, cost is low, can be widely used in various ISM radio-frequency apparatus phase locking frequency stabilizeds such as thermoplastic materials moulding, phenolic moulding powder preheating, the drying of wood, furniture gummed, Seed Treatment, grain heat-drying, RF medical, medicine sterilization, the middle drying of silk dye transfer, plasma roasting quartz, metal heat treatmet and welding and improve performances.

Claims

1, a kind of phase-serve-modulating device for quick precision lock, comprise benchmark crystal oscillator (13), voltage controlled oscillator VCO (1), main phase discriminator (3), loop filter (6), servo amplifier (7), servomotor (8), VCO tuning capacitor (2), it is characterized in that differing in addition limiter (4), D/A converter (5), quadrature phase detector (9), smoothing filter (10), tachometer (12), velocity feedback controller (11), wherein main phase discriminator (3) output to the input serial connection of loop filter (6) differs limiter (4), D/A converter (5), quadrature phase detector (9) input is connected to the input of main phase discriminator (3), and its output connects the input of smoothing filter (10), tachometer (12) output is connected on the input of velocity feedback controller (11), loop filter (6), the output of velocity feedback controller (11) all is connected to the input of servo amplifier (7), smoothing filter (10) output connects the AGC control end of servo amplifier (7), servo amplifier (7) output connects servomotor (8), VCO tuning capacitor (2) and servomotor (8), the same arbor of tachometer (2).

2, according to claims 1 described phase-serve-modulating device for quick precision lock, it is characterized in that differing limiter (4) is to be made of RC integral form shaping gate circuit, and D/A converter (5) input is connected to binary counter, and its output connects amplifier.

3, according to claims 1 described phase-serve-modulating device for quick precision lock, the AGC control end that it is characterized in that servo amplifier (7) is in the amplifier degeneration resistors and connects field effect transistor that its grid is the input of control.

4, according to claims 1 described phase-serve-modulating device for quick precision lock, it is characterized in that servomechanism VCO tuning capacitor (2), servomotor (8), tachometer (12) straight line connects synchronously, it is by the tubular iron core of the inboard tandem arrangement of two end plates (16) (14), and be nested with annular magnetic steel (19), annular pole shoe (18), the cylindrical of tubular iron core (14) is nested with coil rack (17), interior circle is provided with piston (15), and there is axostylus axostyle (20) to stretch out, coil rack (17), the moving plate pole plate (21) of VCO tuning capacitor (2) places on the axostylus axostyle (20), servomotor (8), the coil of tachometer (12) is respectively on coil rack (17), moving plate pole plate (21) ground connection of VCO tuning capacitor (2), stator pole plate (22) connects the resonant groove path of heating oscillator VCO (1).

5,, it is characterized in that velocity feedback controller (11) is the diode by amplifier input serial connection bi-directional voltage stabilizing according to claims 1 described phase-serve-modulating device for quick precision lock.