Bidirectional resonant converter magnetic balance circuit and its control method

Abstract

The invention discloses a magnetic balance circuit of a bidirectional resonant converter and a control method thereof, wherein the magnetic balance circuit of the bidirectional resonant converter comprises a primary side conversion circuit, a transformer, a secondary side conversion circuit and a controller connected in sequence. The circuit is connected to the primary winding W1 of the transformer through the first capacitor C1, a current transformer CT is arranged between the secondary winding of the transformer and the secondary conversion circuit, and the controller converts the circuit cavity according to the secondary side detected by the current transformer CT. The positive component Ipositive of the medium current and the negative component Inegative of the current in the cavity of the secondary side conversion circuit control the duty cycle of the switch in the secondary side conversion circuit; the invention effectively eliminates the magnetic bias phenomenon on both sides of the bidirectional resonant converter, and realizes The balance control of the magnetic circuit avoids saturation, cancels the DC blocking capacitor on the secondary side, reduces the size and cost of the equipment, and only adds a few components on the basis of the original bidirectional resonant converter, which improves the competitiveness of the product.

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 ...

AI Technical Summary

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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