Digital phase locking and frequency tracking electromagnetic induction heating power controller

Abstract

The invention discloses a digital phase locking and frequency tracking electromagnetic induction heating power controller, and belongs to the technical field of electronic circuits. Firstly, sampling is carried out on a current and a voltage output by a full-bridge inverter, phase demodulation output signals Q1 and Q2 are obtained through zero detection and digital phase demodulation, when the high level time of the Q1 is smaller than a half cycle value of a driving signal of a switch tube of the current full-bridge inverter, a load loop is inductive, the Q1 is selected to conduct loop filtering, or the load loop is capacitive, and the Q2 is selected to conduct loop filtering. A compensator calculates the frequency of the driving signal required by the switch tube of the full-bridge inverter in the next cycle, and a DPWM unit generates the driving signal of the switch tube of the full-bridge inverter in the next cycle according to the calculating result of the compensator. The digital phase demodulation is adopted by the controller, a DSP chip is utilized for achieving the frequency tracking, the frequency adjusting range can be effectively improved, and the system efficiency is improved. The controller is simple in structure, effective in control and capable of being suitable for the application requirements for the electromagnetic induction heating power source frequency tracking.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and relates to an electromagnetic induction heating power supply controller, in particular to an electromagnetic induction heating power supply controller based on digital phase locking and having frequency tracking functions. technical background [0002] Based on LC resonance, and the principle of electromagnetic induction, skin effect, proximity effect and ring effect, people invented the electromagnetic induction heating power supply. Electromagnetic induction heating power supply can quickly heat metal workpieces, and is widely used in industrial quenching, forging, smelting and other fields. When the metal workpiece is heated, its physical properties, such as magnetic permeability and electrical conductivity, will change with the increase of temperature, so the equivalent parameters of the load, such as inductance L, resistance R, and capacitance C, will also change with the inc...

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Problems solved by technology

Pure digital phase-locked loops have high requirements on chip speed, and digital low-pass filters are difficult to implement, with limited precision, and on-chip digital phase-locked loops are not suitable for medium and low frequency signals

The software phase-locked loop algorithm is complex, such as the software phase-locked loop mentioned in the Chinese patent "A Method for Realizing a Software Phase-Locked Loop with a Non-fixed Sampling Frequency" (Notice No.: CN101777912A), its signal processing process is complicated, and the processor requirements are relatively high. high

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