Novel AC-DC-AC converter and control method thereof

Abstract

The invention discloses a novel AC-DC-AC converter, which comprises a power frequency power supply, a rectification circuit, an inverter circuit and a resonance circuit. The AC-DC-AC converter is characterized by also comprising a fifth switch tube, inductors connected in series and a fifth diode, wherein the inverter circuit is provided with a sixth diode and a seventh diode. The invention also discloses a control method, which controls on and off states of each switch tube by changing an operating mode symbol xi and duty ratio d, wherein xi is equal to 0 or 1, when xi is equal to 0, Ton is conducting time of the fifth switch tube, and when xi is equal to 1, Ton is straight-through time of the same bridge arm in a bridge type inverter circuit and T is resonance cycle. The AC-DC-AC converter has the advantages that: a switch drive control circuit realizes the change of the operating mode and the adjustment of the duty ratio; the main circuit structure is simple, and DC filtering capacitance as well as impulse current in the process of starting circuits are eliminated; and the resonant current is controlled in constant amplitude when input voltage is changed in a large scale.

Description

technical field The invention relates to the field of energy transmission and control, in particular to a novel AC-DC-AC converter and a control method thereof. Background technique Contactless power transfer (CPT) technology is a new power transmission mode, which comprehensively applies power electronics technology, magnetic field coupling technology and modern control theory, etc., through the magnetic field coupling between the primary loop and the secondary loop coil to realize the power from the power system to the The method of non-electrical direct contact transmits electrical energy to one or more electrical equipment (including mobile electrical equipment). In multi-load mode, in order to remove or reduce the coupling characteristics between loads, it is an effective measure to modulate the primary resonant current of the CPT system to a high-frequency alternating current with constant frequency and constant amplitude, and it is also a research focus of the CPT sy...

AI Technical Summary

Problems solved by technology

(1) The filter capacitors before and after the DC / DC converter are large in size, high in price, and limited in life. As the power increases, the volume of the capacitor increases accordingly

(2) When the system power is large, the rectified filter capacitor needs to add a soft-start circuit to reduce the inrush current, which increases the volume, cost and control difficulty of the system

(3) When the input voltage fluctuates in a large range, it is difficult to realize the constant amplitude control of the resonant current, and the stability of the system is poor

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