Bidirectional resonant converter magnetic balance circuit and control method thereof

Abstract

The invention discloses a bidirectional resonant converter magnetic balance circuit and a control method thereof. The bidirectional resonant converter magnetic balance circuit comprises a primary sideconversion circuit, a transformer, a secondary side conversion circuit and a controller which are connected in sequence, and the primary side conversion circuit is connected with a transformer primary side winding W1 through a first capacitor C1; and a current transformer CT is arranged between the secondary winding of the transformer and the secondary conversion circuit, and the controller controls the duty ratio of a switch in the secondary conversion circuit according to the positive component Ipositive of the current in the cavity of the secondary conversion circuit and the negative component Inegative of the current in the cavity of the secondary conversion circuit, which are detected by the current transformer CT. The magnetic bias phenomenon on the two sides of the bidirectional resonant converter is effectively eliminated, balance control over a magnetic circuit is achieved, saturation is avoided, a blocking capacitor on the secondary side is omitted, the equipment size and cost are reduced, only a small number of elements are added on the basis of an original bidirectional resonant converter, and the product competitiveness is improved.

Description

technical field [0001] The invention relates to a power converter, in particular to a bidirectional resonant converter magnetic balance circuit and a control method thereof. Background technique [0002] With the popularity of bidirectional isolation topologies, especially in automotive OBC, photovoltaic, energy storage and other applications, the need for isolation transformers and bidirectional power transmission is more urgent. Among the traditional two-way power transmission topologies, the two-way resonant topology (CLLC) architecture, the double-sided active switching topology (DAB) architecture, and the full-bridge series resonant topology (DBSRC) topology are popular. In these topologies, due to the need to consider the magnetic balance problem, capacitors need to be connected in series in both the primary side loop and the secondary side loop, and the DC component is blocked by using the capacitor’s “blocking DC and passing through” characteristics, thereby solving ...

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Problems solved by technology

[0004] 1. Capacitors are connected in series on both sides of the power. If the high-energy transmission needs to be realized, the current is often high. At this time, the volume and cost of the capacitor will increase significantly, reducing product competitiveness;

[0005] 2. The solution to the magnetic balance problem through the peak current control mode can only be applied in the DAB topology, and the control algorithm has high requirements. It needs to use the internal comparator of the DSP, and it is basically impossible to realize the upgrade of the three ports on this basis. ;

[0006] 3. In the control of DBSRC, the peak current control mode cannot be used, only by adding capacitors on both sides of the power, one of the capacitors is for resonance, and the other is for "blocking direct traffic"

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