The invention relates to a high power wideband ultrasonic power supply based on silicon carbide device and a control method thereof. The power supply comprises a PWM rectifying circuit, a DC chopping power adjusting circuit, a full bridge inversion circuit, a main transformer, a matching network, a matching network driving circuit, a digital control circuit, a phase locking circuit, a voltage sampling circuit, a current sampling circuit, a power adjusting control circuit, a protection circuit, a driving circuit, a DDS (direct digital frequency circuit), a piezoelectric transducer and the like. Power switch devices used by the PWM rectifying circuit, the DC chopping power adjusting circuit and the full bridge inversion circuit are all large energy gap silicon carbide devices. The switch frequency, the transformation frequency, the power density and the reliability of the power supply are remarkably improved, the output power is 1kw-10kw, the frequency search range is 18-100 kHz, and the power supply adopts a variable step frequency tracking digital method based on resonant frequency automatic identification.

High power wideband ultrasonic power supply based on silicon carbide device and control method thereof

The invention discloses a frequency tracking device of a wireless energy transmitting system, wherein the frequency tracking device is based on single-chip microcomputer control. The frequency tracking device of the wireless energy transmitting system comprises a full-bridge inverter circuit drive circuit, a DDS chip, a single-chip microcomputer, a phase difference detecting circuit, a primary winding loop, a voltage sampling circuit, a current sampling circuit and an amplifying and shaping circuit. The invention further discloses a frequency tracking method of the frequency tracking device applied to the wireless energy transmitting system. The frequency tracking method comprises the following steps that firstly, the single-chip microcomputer reflects a frequency tracking result with frequency data and transmits the frequency data into the DDS chip; secondly, the controlled quantity output by a phase detecting circuit is kept constant only in the detuned state or in the resonance state; thirdly, the frequency control word of the DDS chip is updated in time by the single-chip microcomputer so that a new working frequency can be generated to drive an inverter circuit, and meanwhile the phase detecting circuit conducts circle detection and judgment until the resonance of system recovers. The frequency tracking device of the wireless energy transmitting system and the frequency tracking method of the frequency tracking device have the advantages that the structure is simple, and the problem of frequency detuning of the wireless energy transmitting system is effectively solved.

Frequency tracking device of wireless energy transmitting system and frequency tracking method thereof

The invention relates to an ultrasonic power source for transducer cascading. The ultrasonic power source comprises a rectifier bridge, a filter circuit, a direct-current chopper circuit, a full-bridge inverter circuit, a first impedance stepless matching network, a second impedance stepless matching network, a first transducer, a second transducer, a matching network control circuit, a voltage current sampling circuit, a frequency tracking circuit, and a constant power circuit. The matching network control circuit controls magnitude of matching inductors of the first and second impedance stepless matching networks, accessing an inverter output circuit. Output voltage and current of the full-bridge inverter circuit are connected to the frequency tracking circuit and the constant power circuit through the sampling circuit; the frequency tracking circuit controls full-bridge inversion frequency; the constant power circuit controls magnitude of the output voltage of the direct-current chopper circuit. The ultrasonic power source has the advantages that coaction of the first and second matching network control circuits ensures normal operation of transducer cascading and the traditional single-inverter single-transducer operating mode is changed.

Ultrasonic power source for transducer cascading

The invention discloses an impedance matching system and method and a control system of a supersonic power supply. The impedance matching system comprises an impedance matching network and an energy transducer equivalent network, and is characterized in that the impedance matching network is coupled to a main circuit of the supersonic power supply, and the impedance matching network comprises an equivalent inductor Le which is formed by the a leakage inductance of the main circuit of supersonic power supply and has inductance characteristics. Compared with the prior art, the systems and method have the advantages that a virtual inductance matching mode is sued, leakage inductance existing when a pulse transformer is wound is utilized fully, certain compensation capacitors are connected in parallel to carry out resonance and impedance matching of energy transducer and tool head system, the cost of an entity matching inductor is reduced, the total weight and energy consumption of heating of the entity inductor are reduced, materials are saved, and consumption is reduced.

Impedance matching system and method and control system of supersonic power supply

Ultrasonic water treatment is based on the ability of an ultrasonic device to induce cavitation in the liquid, generating physical and chemical effects that can be used for biological inactivation. Effective treatment requires the ultrasonic device to generate intense cavitation field in a large treatment volume. Most conventional ultrasonic radiators fulfil only the first of these two requirements, rendering such devices highly unsuitable for use in high-volume, high-flow liquid processes. The present research investigates the design and performance of a new type of radial resonator in terms of their electromechanical characteristics, nonlinear behaviour, and their ability to treat synthetic ballast water with lower power consumption and short treatment times.

The radial resonators were designed using finite element (FE) modelling, and the best designs related to their predicted modal behaviour and vibration uniformity were selected for fabrication and experimental evaluation. Experimental modal analysis (EMA) of the radial resonators showed excellent correlation with the FE models, deviating by only 0.3% at the tuned mode. Impedance analysis showed that the mechanical quality factor of the radial resonators are 28–165% higher than the commercial high-gain probe, but their coupling coefficients are 40–45% lower.

Harmonic response characterisation (HRC) revealed shifts in the resonance frequencies at elevated excitation voltages. Duffing-like behaviour were observed in all resonators. RP-1 exhibited the Duffing-like behaviour to a far greater extent compared to the RPS-16 and RPST-16 multiple orifice resonators, indicating the influence of geometric parameters on the overall stiffness of the structure.

Finally, experiments with Artemia nauplii and Daphnia sp. showed excellent biological inactivation capability of the radial resonators. Comparison with previous studies showed that 90% reduction in Artemia nauplii can be achieved with up to 33% less energy and using just one radial resonator compared to the dozens of conventional resonators used in precedent investigations.

The present research have successfully demonstrated the use of FE modeling, EMA, and HRC to develop, validate, and characterise a new type of radial resonator. Experimental analysis showed that the radial resonators exhibited promising electrical, mechanical, and acoustical characteristics that has the potential to be cost-efficient, scalable, and a viable alternative water treatment method.

Ultrasonic disinfection using large area compact radial mode resonators

The resonance characteristics of ultrasonic transducer are analyzed based on the equivalent circuit of transducer and the quantitative calculation of admittance circle, and a control method of frequency tracking based on variable step length is proposed, and the limits of step switching are deduced, and the control parameters of the control method based on variable step length is designed in this paper. The results of simulation and experiment show that the system based on the control method can control output frequency in high precision. And while ultrasonic power supply ensure steady-state error minimum, holding a good dynamic performance, which meets the requirements of the technology of ultrasonic power supply.

http://ieeexplore.ieee.org/iel7/7027308/7037809/07037889.pdf

The research on phase lock method of ultrasonic power supply with variable step length control

The utility model relates to an ultrasonic power supply for transducer cascade. The ultrasonic power supply comprises a rectifier bridge, a filter circuit, a DC chopper circuit, a full bridge inverter circuit, a first impedance stepless matching network, a second impedance stepless matching network, a first transducer, a second transducer, a matching network control circuit, a voltage and current sampling circuit, a frequency tracking circuit, and a power constant circuit. The matching network control circuit controls the size of the matching inductance of the first impedance stepless matching network and the second impedance stepless matching network connected to an inverter output circuit. According to the ultrasonic power supply, through the common action of the frequency tracking circuit and the first and second impedance stepless matching networks, the normal working of the transducer cascade can be ensured, and the operation mode of the previous single inverter single transducer is changed.

Luo Jie

Papers

The research on phase lock method of ultrasonic power supply with variable step length control

Ultrasonic power source for transducer cascading

Ultrasonic power supply for transducer cascade