Voltage-regulating variable-frequency hierarchical control ultrasonic plastic welding power supply

Abstract

The invention discloses a voltage-regulating variable-frequency hierarchical control ultrasonic plastic welding power supply, which comprises a sampling control unit, a rectifying and DC voltage-regulating unit, a fixed phase-shift angle inversion unit, a matching boosting isolating unit and an ultrasonic transducer. The sampling control unit comprises a microprocessor, a first signal conditioning circuit, a second signal conditioning circuit, a driving circuit, an effective value detection circuit and a phase detection circuit, wherein the first signal conditioning circuit and the driving circuit are connected with the microprocessor; the second signal conditioning circuit is respectively connected with the effective value detection circuit and the phase detection circuit; and the effective value detection circuit and the phase detection circuit are both connected with an AD sampling port of the microprocessor. The voltage-regulating variable-frequency hierarchical control ultrasonic plastic welding power supply has the advantages that output voltage and current waveform THD is small, the voltage-regulating range is wide, large-power ultrasonic welding can be realized, the voltage-regulating or power-regulating response is quick, the voltage ripple is small, the transducer has a small vibration amplitude fluctuation, the frequency tracking precision and the accuracy are high, the electric conversion efficiency is high and the like.

Description

technical field [0001] The invention relates to an ultrasonic welding power supply, in particular to an ultrasonic plastic welding power supply controlled by step-by-step voltage regulation and frequency conversion. Background technique [0002] The existing ultrasonic plastic welding power supplies can be roughly divided into two categories: series resonant tracking and parallel resonant tracking according to different operating frequencies. The current source control method that tracks the series resonance frequency has higher power and better frequency following performance, but the electrical conversion efficiency is not high and the stability is not good. The voltage source control method of tracking the parallel resonance frequency has high electrical conversion efficiency, but the power is not large, and the frequency following performance is not good. [0003] The existing digitally controlled voltage-controlled ultrasonic welding power supply generally uses an inve...

AI Technical Summary

Problems solved by technology

When the current is small, the method of tracking the minimum value of the current may cause detuning. In addition, when the admittance circle deviates far from the X-axis, the load impedance angle corresponding to the maximum impedance frequency is relatively large, which will generate a relatively large reactive component. It is not conducive to the active power output of the power supply

When the current and voltage waveforms are poor, the method of phase tracking may not find the anti-resonance point, resulting in detuning, so there are certain defects

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