Frequency self-adaptive circuit of parallel resonant induction heating power supply

Abstract

The invention belongs to the electric technical field and discloses a frequency self-adaptive circuit of a parallel resonant induction heating power supply. The frequency self-adaptive circuit comprises a swept-frequency start circuit (1), a frequency tracking circuit (2), an overlap area processing circuit (3) and a signal gating circuit (4), wherein the swept-frequency start circuit (1) is used for outputting swept-frequency driving signals which change continuously in frequency, driving an inverter through the signal gating circuit and detecting feedback signals output by the inverter, and when the amplitude of the feedback signals achieves a threshold value, a system is converted from swept-frequency start to frequency tracking, and the frequency tracking circuit is used for tracking the changes of a load in resonance frequency in a real-time manner; and the overlap area processing circuit is used for adjusting an overlap area of two lines of driving signals. The frequency self-adaptive circuit disclosed by the invention can realize reliable start and tracking within a wider load frequency range without artificial adjustment and has the characteristics of simple structure, good adaptability of the load and reliable start.

Description

technical field [0001] The invention belongs to the field of electrical technology, and discloses a parallel resonance induction heating power supply frequency adaptive circuit. Background technique [0002] At present, induction heating is widely used in smelting, diathermy, quenching and other fields due to its advantages of high heating efficiency, fast temperature rise, and good controllability. Induction heating power supply is one of its key equipment. However, the output frequency of the power supply is determined by the geometry and skin depth of the processed workpiece. Different workpieces and process requirements require the power supply to work in a wider frequency range, and parallel resonance induction heating power supplies may appear in a wider frequency range. Difficult problem to start. At the same time, during the heating process, due to changes in temperature and other factors, the natural resonant frequency of the load changes with the change of the equ...

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Problems solved by technology

[0003] The traditional CD4046 analog phase-locked loop induction heating power supply has the disadvantages of narrow starting frequency range, low starting success rate, and slow response after frequency locking

At present, the digital induction heating power supply has not yet realized the complete digitalization of the system, the interface is complicated, and the cost is high

[0004] The patent No. 200610023406.7 relates to the start-up tracking technology of the induction heating power supply, but the technology described in the document is passively tracking the start-up voltage when the tracker is started. When the load resonance frequency changes greatly (such as changing the process ) requires professional adjustment

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