CN204761297U - High -power broadband ultrasonic power supply based on carborundum device - Google Patents

Abstract

The utility model relates to a high -power broadband ultrasonic power supply based on carborundum device, transfer merit circuit, full bridge inverter, main transformer, matching network, matching network drive circuit, digital control circuit, phase lock circuitry, voltage sampling circuit, electric current sampling circuit, transfer merit control circuit, protection circuit, drive circuit, DDS (direct digital full bridge inverter 1) circuit, full bridge inverter 2 etc. Including PWM rectifier circuit, direct current copped wave. Wherein PWM rectifier circuit, the direct current copped wave power switch device of transferring merit circuit and full bridge inverter to use is broad stopband carborundum device, and switching frequency, conversion efficiency, power density and the reliability of power all have apparent promotion.

Description

Based on the large-power broadband ultrasonic power of silicon carbide device

Technical field

The utility model relates to ultrasonic power technical field, is specifically related to a kind of large-power broadband ultrasonic power based on silicon carbide device.

Background technology

Ultrasonic power is commonly referred to ultrasonic wave generating source, and its effect is that electric energy is converted to the high-frequency ac signal of telecommunication matched with ultrasonic transducer.The load normally piezoelectric ceramic transducer of ultrasonic power, there is direct capacitance in piezoelectric ceramic transducer, in the course of the work, its resonant frequency point will drift about piezoelectric ceramic transducer, therefore, ultrasonic power must possess the ability of tracking ultrasound transducers resonance frequency.

At present, conventional ultrasonic power frequency tracking method has, and maximum current search resonant frequency method, frequency of phase locking tracking, matching network regulate method.Matching network regulates the control precision of method will be subject to the impact of minimum switching inductance, the method of maximum current search resonance frequency and frequency of phase locking tracking all must search for the resonance frequency of transducer within the specific limits, need to spend a large amount of computing cycles to find the resonance frequency of transducer from power initiation to stable state, system is longer from the transit time starting to stable state.

Utility model content

The utility model object is openly a kind of large-power broadband ultrasonic power based on silicon carbide device.

A kind of large-power broadband ultrasonic power based on silicon carbide device of the present utility model and control method thereof, its switching tube used is silicon carbide device, there is energy consumption low, frequency advantages of higher, power-supply system has the function automatically identifying transducer load resonant frequency, then utilize variable step to follow the tracks of and carry out tracking correction to transducer resonance frequency, proof load is in resonance condition, and system has shorter transit time.

The purpose of this utility model can realize by the following technical solutions.

Based on the large-power broadband ultrasonic power of silicon carbide device, it comprises PWM rectification circuit, DC chopped-wave power regulation circuit, full bridge inverter, main transformer, voltage sample circuit, current sampling circuit, matching network, matching network drive circuit, PZT (piezoelectric transducer), protective circuit, Power Regulation control circuit, drive circuit, DDS circuit, phase lock circuitry and digital control circuit, PWM rectification circuit, full bridge inverter and DC chopper circuit all have employed broad stopband device silicon carbide power field effect transistor as power switch, the input access civil power of PWM rectification circuit, the input of its output access DC chopped-wave power regulation circuit, the output access input of full bridge inverter of DC chopped-wave power regulation circuit and the input of voltage sample circuit, the primary input terminal of the output access main transformer of full bridge inverter, secondary second end of output first end access matching network first inductance of main transformer and the first end of PZT (piezoelectric transducer), secondary output second termination of main transformer enters the first input end of current sampling circuit, second end of PZT (piezoelectric transducer) is connected with the second end of matching network second inductance and the second input of current sampling circuit, the output of the input termination phase lock circuitry of digital control circuit, the input of the first output access DDS circuit of digital control circuit, the input of the output access drive circuit of DDS circuit, the drive end of the output access full bridge inverter of drive circuit, the input of the second output access matching network drive circuit of digital control circuit, the gate pole of the first thyristor of the first output access matching network of matching network drive circuit, the gate pole of the second thyristor of the second output access matching network of matching network drive circuit, the negative electrode of the first thyristor is connected with the first end of the anode of the second thyristor and the first inductance, the anode of the first thyristor is connected with the first end of the negative electrode of the second thyristor and the second inductance, the output of current sampling circuit and the output of voltage sample circuit access first input end and second input of Power Regulation control circuit respectively, the input of the output access Power Regulation control circuit of protective circuit, the output of the input termination current sampling circuit of protective circuit, the drive end of the output access DC chopped-wave power regulation circuit of Power Regulation control circuit, the first input end of the output access phase lock circuitry of current sampling circuit, second input of the sampling end access phase lock circuitry of drive circuit, the voltage signal that drive circuit sampling end exports is as the Voltage Feedback of phase lock circuitry.

Compared with the prior art the utility model has the following advantages:

A kind of large-power broadband ultrasonic power based on silicon carbide device that the utility model proposes is different from traditional ultrasonic power, traditional ultrasonic power adopts MOS switching tube or IGBT switching tube, its operating frequency is by power supply output power limit, traditional ultrasonic power frequency tracking method needs the resonance frequency of searching for ultrasonic power within the scope of certain frequency, need the computing cycle of at substantial, the transit time of system is longer.

A kind of large-power broadband ultrasonic power based on silicon carbide device that the utility model proposes uses broad stopband silicon carbide device, the frequency that power supply exports is less by power influences, can meet high-power, high-frequency demand, and power-supply system has the function that resonance frequency identifies automatically, by the double sampling under different output frequency condition, through calculating, substantially the resonance frequency of transducer load can be drawn, sampling process only needs two sampling periods of cost, compared with traditional frequency tracking method, there is transit time short, the advantage that dynamic response is fast.

Accompanying drawing explanation

Fig. 1 is the ultrasonic power formation schematic diagram based on carborundum.

Fig. 2 identifies a kind of example control flow chart with variable step tracing control automatically based on resonance frequency.

Embodiment

Below in conjunction with accompanying drawing and concrete enforcement, the utility model is further described in detail.

A kind of large-power broadband ultrasonic power based on silicon carbide device disclosed in the utility model as shown in Figure 1.Based on the large-power broadband ultrasonic power of silicon carbide device, it comprises PWM rectification circuit 1, DC chopped-wave power regulation circuit 2, full bridge inverter 3, main transformer 4, voltage sample circuit, current sampling circuit, matching network, matching network drive circuit, PZT (piezoelectric transducer), protective circuit, Power Regulation control circuit, drive circuit, DDS (direct digital synthesis technique) circuit, phase lock circuitry and digital control circuit, PWM rectification circuit, full bridge inverter and DC chopper circuit all have employed broad stopband device silicon carbide power field effect transistor as power switch, the input access civil power of PWM rectification circuit, the input of its output access DC chopped-wave power regulation circuit, the output access input of full bridge inverter of DC chopped-wave power regulation circuit and the input of voltage sample circuit, the primary input terminal of the output access main transformer of full bridge inverter, secondary second end of output first end access matching network first inductance L 1 of main transformer and the first end of PZT (piezoelectric transducer), secondary output second termination of main transformer enters the first input end of current sampling circuit, second end of PZT (piezoelectric transducer) is connected with the second end of matching network second inductance L 2 and the second input of current sampling circuit, the output of the input termination phase lock circuitry of digital control circuit, the input of the first output access DDS circuit of digital control circuit, the input of the output access drive circuit of DDS circuit, the drive end of the output access full bridge inverter of drive circuit, the input of the second output access matching network drive circuit of digital control circuit, the gate pole G1 of the first thyristor THY1 of the first output access matching network of matching network drive circuit, the gate pole G2 of the second thyristor THY2 of the second output access matching network of matching network drive circuit, the negative electrode K1 of the first thyristor THY1 is connected with the first end of the anode A 2 of the second thyristor THY2 and the first inductance L 1, the anode A 1 of the first thyristor THY1 is connected with the first end of the negative electrode K2 of the second thyristor THY2 and the second inductance L 2, the output of current sampling circuit and the output of voltage sample circuit access first input end and second input of Power Regulation control circuit respectively, the input of the output access Power Regulation control circuit of protective circuit, the output of the input termination current sampling circuit of protective circuit, the drive end of the output access DC chopped-wave power regulation circuit of Power Regulation control circuit, the first input end of the output access phase lock circuitry of current sampling circuit, second input of the sampling end access phase lock circuitry of drive circuit, the voltage signal that drive circuit sampling end exports is as the Voltage Feedback wherein PWM rectification circuit of phase lock circuitry, the device for power switching that DC chopped-wave power regulation circuit and full bridge inverter use is broad stopband silicon carbide device, the switching frequency of power supply, conversion efficiency, power density and reliability all have remarkable lifting, power output 1kW-10kW, frequency search range 18kHz-100kHz.Power supply have employed the modified model variable step digital control method automatically identified based on resonance frequency.Phase lock circuitry can feed back the phase difference of electric power output voltage, the lead lag relationship of electric current and electric power output voltage, electric current, the phase information that digital control circuit is fed back by phase lock circuitry, the algorithm good through internal composition calculates, the frequency that power supply exports alternating voltage can be controlled, enable the frequency of output alternating voltage follow the tracks of the resonance frequency of transducer load fast and accurately.

In above-mentioned ultrasonic power, digital control circuit controls the size of matching network access main circuit equivalent inductance by matching network drive circuit, the inductance size of matching network and the electric capacity of transducer is matched, reaches required resonance effect.

This example ultrasonic power has resonance frequency automatic identification function to transducer load, the duty ratio of the phase lock circuitry output pulse of power source internal directly feeds back the phase difference of electric power output voltage, output current, the load of power supply is piezoelectric ceramic transducer, the dynamic electric inductance value of piezoelectric ceramic transducer is L, dynamic electric capacitance is C, and differential resistance values is R.The power output 1kW-10kW of ultrasonic power, the frequency range 18kHz-100kHz of ultrasonic power.

As an example, software section is that those skilled in the art can refer to existing techniques in realizing.Perform an analysis to operation principle below: digital control circuit and the communication of DDS circuit produce given first frequency signal and second frequency signal, it is f respectively that first frequency signal and second frequency signal control full bridge inverter output frequency respectively by drive circuit ₁and f ₂alternating current, digital control circuit gathers full bridge inverter output voltage frequency and is respectively f ₁and f ₂in situation, phase lock circuitry exports the duty ratio D of pulse ₁, D ₂, then full bridge inverter output voltage frequency f ₁, f ₂load impedance angle corresponding in situation is respectively:

θ ₁＝D ₁*π(4-1)

θ ₂＝D ₂*π(4-2)

Then can obtain:

$\left\{\begin{array}{c}\tan {\mathrm{\θ}}_1=\frac{{2\mathrm{\πf}}_{1}L-\frac{1}{{2\mathrm{\πf}}_{1}C}}{R}\\ \tan {\mathrm{\θ}}_2=\frac{{2\mathrm{\πf}}_{2}L-\frac{1}{{2\mathrm{\πf}}_{2}C}}{R}\end{array}\right.---(4-3)$

Then equation 4-3 is variable is changed to:

$\left\{\begin{array}{c}\tan {\mathrm{\θ}}_1=A\frac{L}{R}-\frac{1}{\mathrm{ARC}}\\ {\tan \mathrm{\θ}}_2=B\frac{L}{R}-\frac{1}{\mathrm{BRC}}\end{array}\right.---(4-4)$

Wherein:

$\left\{\begin{array}{c}A=2{\mathrm{\πf}}_1\\ B=2{\mathrm{\πf}}_2\end{array}\right.---(4-5)$

Can be in the hope of:

$\left\{\begin{array}{c}\frac{1}{\mathrm{RC}}=\frac{{\mathrm{AB}}^2{\tan \mathrm{\θ}}_1-A^{2}B\tan {\mathrm{\θ}}_2}{A^2-B^2}=M\\ \frac{L}{R}=\frac{A\tan {\mathrm{\θ}}_1-B\tan {\mathrm{\θ}}_2}{A^2-B^2}=N\end{array}\right.---(4-6)$

Because the resonance frequency of transducer is:

$f_s=\frac{1}{2\mathrm{\π}\sqrt{\mathrm{LC}}}---(4-7)$

Therefore, can obtain:

$f_s=\frac{\sqrt{\frac{M}{N}}}{2\mathrm{\π}}---(4-8)$

Realize the automatic identification of resonance frequency, due to ultrasonic transducer load in the course of the work its resonance frequency can produce drift, therefore after the resonance frequency obtaining ultrasonic transducer, the output frequency of variable step tracing control to ultrasonic power can also be utilized to revise as preferred example, as preferred example, described variable step tracing control comprises the steps: the electric power output voltage that (1) digital control circuit feeds back according to phase lock circuitry, current and phase difference θ obtains the gap of output voltage frequency and transducer resonance frequency, if the phase difference reference threshold that step-length switches is when the phase difference of output voltage, electric current time, adopt the large step-length of setting to follow the tracks of transducer resonance frequency, when the phase difference of electric power output voltage, electric current time, adopt the little step-length exchange of setting device resonance frequency to follow the tracks of, (2) when electric power output voltage leading current, the step-length determined according to step (1) reduces output frequency, when electric power output voltage lagging current, the step-length determined according to step (1) increases output frequency, after the time delay of setting, get back to step (1).

Preferably, described phase difference reference threshold the step-length step determined with step (1) should meet relational expression

$\mathrm{\φ}>\mathrm{Krel}*\left|\arctan ((\sqrt{\frac{M}{N}}-\mathrm{\π}*\mathrm{step})N-\frac{M}{\sqrt{\frac{M}{N}}-\mathrm{\π}*\mathrm{step}})\right|---(5-1)$

Wherein Krel be greater than 1 setting coefficient of safety.

Below in conjunction with concrete instance data and accompanying drawing, embodiment is described again.The frequency tracing control flow chart of power-supply system as shown in Figure 2, after power initiation, digital control circuit and the communication of DDS circuit produce given first frequency signal and second frequency signal, and it is f respectively that first, second frequency signal controls full bridge inverter output frequency by drive circuit ₁and f ₂alternating voltage, utilize phase lock circuitry full bridge inverter output voltage frequency of sampling respectively to be respectively f ₁and f ₂time corresponding electric power output voltage, current and phase difference angle θ ₁and θ ₂, phase difference angle is identical with load impedance angle, can calculate transducer load resonant frequency f by resonance frequency algorithm _s, then power supply is to calculate the resonance frequency f of gained _sexport alternating voltage, to reduce ultrasonic power from the transit time starting to stable state, because ultrasonic transducer load its resonance frequency in work process can produce drift, therefore after calculating resonance frequency, also need to utilize variable step tracing control to revise its transducer resonance frequency, the electric power output voltage that digital control circuit feeds back according to phase lock circuitry, current and phase difference signal magnitude and then obtain the gap of output voltage frequency and transducer resonance frequency, the phase difference reference threshold that step-length switches determined by formula (5-1), suppose transducer dynamic electric resistor R=15 Ω, dynamic inductance L=35mH, dynamic capacity C=1.81pF, Krel=1.5, step=10Hz, for preventing step-length handoff failure, when the phase difference of output voltage, electric current time, then power supply output frequency and transducer resonance frequency gap are comparatively large, adopt large step-length to carry out frequency search, now step=10Hz, make power supply output frequency follow the tracks of transducer resonance frequency quickly, when the phase difference of electric power output voltage, electric current time, then power supply output frequency and transducer resonance frequency gap less, the little step length searching of power acquisition, step=0.01Hz, to ensure that system has higher FREQUENCY CONTROL precision and less steady-state error, when voltage leading current, output frequency f=f-step, reduces frequency; When voltage delay electric current, output frequency f=f+step, increases frequency.Circulation like this, power-supply system rapidly and accurately can follow the tracks of transducer resonance frequency.

Claims (1)

1., based on the large-power broadband ultrasonic power of silicon carbide device, it is characterized in that comprising PWM rectification circuit, DC chopped-wave power regulation circuit, full bridge inverter, main transformer, voltage sample circuit, current sampling circuit, matching network, matching network drive circuit, PZT (piezoelectric transducer), protective circuit, Power Regulation control circuit, drive circuit, DDS circuit, phase lock circuitry and digital control circuit; PWM rectification circuit, full bridge inverter and DC chopper circuit all have employed broad stopband device silicon carbide power field effect transistor as power switch; the input access civil power of PWM rectification circuit, the input of its output access DC chopped-wave power regulation circuit, the output access input of full bridge inverter of DC chopped-wave power regulation circuit and the input of voltage sample circuit, the primary input terminal of the output access main transformer of full bridge inverter, secondary second end of output first end access matching network first inductance (L1) of main transformer and the first end of PZT (piezoelectric transducer), secondary output second termination of main transformer enters the first input end of current sampling circuit, second end of PZT (piezoelectric transducer) is connected with the second end of matching network second inductance (L2) and the second input of current sampling circuit, the output of the input termination phase lock circuitry of digital control circuit, the input of the first output access DDS circuit of digital control circuit, the input of the output access drive circuit of DDS circuit, the drive end of the output access full bridge inverter of drive circuit, the input of the second output access matching network drive circuit of digital control circuit, the gate pole (G1) of first thyristor (THY1) of the first output access matching network of matching network drive circuit, the gate pole (G2) of second thyristor (THY2) of the second output access matching network of matching network drive circuit, the negative electrode (K1) of the first thyristor (THY1) is connected with the first end of the anode (A2) of the second thyristor (THY2) and the first inductance (L1), the anode (A1) of the first thyristor (THY1) is connected with the first end of the negative electrode (K2) of the second thyristor (THY2) and the second inductance (L2), the output of current sampling circuit and the output of voltage sample circuit access first input end and second input of Power Regulation control circuit respectively, the input of the output access Power Regulation control circuit of protective circuit, the output of the input termination current sampling circuit of protective circuit, the drive end of the output access DC chopped-wave power regulation circuit of Power Regulation control circuit, the first input end of the output access phase lock circuitry of current sampling circuit, second input of the sampling end access phase lock circuitry of drive circuit, the voltage signal that drive circuit sampling end exports is as the Voltage Feedback of phase lock circuitry.