A multi-phase parallel resonant converter capable of automatic current balancing

Abstract

The present invention provides a multi-phase parallel resonant converter capable of automatically equalizing current, wherein the resonant transformer of each phase resonant converter has two identical secondary windings: a first secondary winding and a second secondary winding; all first secondary windings are connected in series and then connected to the input end of the first phase rectifier circuit; all second secondary windings are connected in series and then connected to the input end of the second phase rectifier circuit. The beneficial effects of the present invention are: automatic balancing of the currents of each branch of the multi-phase parallel resonant converter is achieved, so that the power distribution of each branch is equal, and the high-power parallel switching power supply used in electric vehicles, hybrid vehicles, uninterruptible power supplies, power quality regulation power supplies, aviation power supplies, new energy power generation, superconducting energy storage, etc. has the advantages of low loss, high efficiency, and avoiding local overheating of switch tubes or rectifier diodes or excessive voltage and current stress of devices.

Description

Technical Field

[0001] This patent relates to a multi-phase parallel power electronic resonant converter capable of automatic current equalization, which can achieve automatic current equalization of each parallel branch. Technical Background

[0002] In recent years, switching power supplies that provide electrical energy to various electrical equipment are developing in the direction of low voltage, high current, small size, light weight, high efficiency, thinness and integration, including voltage adjustment modules that provide precision power for high-precision, high-speed microprocessors such as the computer's central processing unit (CPU) and digital signal processor (DSP), as well as switching power supplies that have emerged in recent years and are widely used in electric vehicles, hybrid vehicles, uninterruptible power supplies, power quality regulation power supplies, aviation power supplies, new energy power generation and superconducting energy storage. These switching power supplies adopt the circuit topology of a resonant converter, so that the switch tube can achieve zero voltage turn-on and zero current turn-off within the full load range, thereby reducing losses and improving efficiency. In order to achieve high-power applications of resonant converters, people often use a two-phase or multi-phase parallel resonant converter circuit topology. However, due to the inconsistent parameters of the resonant capacitor or resonant inductor of each parallel branch of the resonant converter, the currents of each branch are not equal, and the power distribution of each branch is not equal, which brings serious problems such as local overheating of the switch tube or rectifier diode or excessive voltage and current stress of the device. Summary of the invention

[0003] In response to the defects of the existing technology, this patent provides a multi-phase parallel resonant converter that can automatically balance the current, which has the advantages of simple structure, low loss, high efficiency, and automatic current equalization of each parallel branch.

[0004] The technical solution adopted by this patent to solve its technical problems is:

[0005] A multi-phase parallel resonant converter capable of automatically balancing current, comprising:

[0006] The first phase resonant converter Phase1 includes a first switch circuit S1, a first resonant capacitor C1, a first resonant inductor L r1 , the first resonant transformer T1, the primary winding N connected in parallel to the first resonant transformer T1 P1 The first equivalent excitation inductance L at both ends a and b m1 , a first rectifier circuit R1; the first resonant capacitor C1, the first resonant inductor L r1and the first resonant transformer T1 are connected in series to form a first resonant unit; the first switch circuit S1 has an input port 1-1 and an output port 1-2, and the first rectifier circuit R1 has an input port 1-3 and an output port 1-4;

[0007] The second phase resonant converter Phase2 includes a second switch circuit S2, a second resonant capacitor C2, a second resonant inductor L r2 , the second resonant transformer T2, the primary winding N connected in parallel to the second resonant transformer T2 P2 The second equivalent excitation inductance L at both ends g and h m2 , a second rectifier circuit R2; the second resonant capacitor C2, the second resonant inductor L r2 The second resonant transformer T2 is connected in series to form a second resonant unit; the second switch circuit S2 has an input port 2-1 and an output port 2-2, and the second rectifier circuit R2 has an input port 2-3 and an output port 2-4;

[0008] Features:

[0009] The first resonant transformer T1 has two identical secondary windings N S11 and N S12 The second resonant transformer T2 has two identical secondary windings N S21 and N S22 , the secondary winding N S11 and N S21 phases are connected in series and then connected to the input terminals 1-3 of the first rectifier circuit R1; the secondary winding N S12 and N S22 phases are connected in series and then connected to the input terminal 2-3 of the second rectifier circuit R2.

[0010] The beneficial effect of this patent is that this patent provides a multi-phase parallel resonant converter that can automatically balance current, wherein the first phase resonant transformer and the second phase resonant transformer both have two identical secondary windings, the first secondary winding of the first phase resonant transformer and the first secondary winding of the second phase resonant transformer are connected in series and then connected to the input port of the first phase rectifier circuit; the second secondary winding of the first phase resonant transformer and the second secondary winding of the second phase resonant transformer are connected in series and then connected to the input port of the second phase rectifier circuit, so that the total secondary current of the first phase resonant transformer and the total secondary current of the second phase resonant transformer can be equal, thereby ensuring that the primary current of the first phase resonant transformer and the primary current of the second phase resonant transformer are equal, and ensuring that the output current of the first phase rectifier and the output current of the second phase rectifier are equal, realizing automatic balancing of the currents of each branch of the multi-phase parallel resonant converter, and being used for high-power switching power supplies, with the advantages of low loss, high efficiency, avoiding local overheating of switching tubes or rectifier diodes or excessive device voltage and current stress, etc.

[0011] The following is a specific description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to explain the embodiments more clearly, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of this patent, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 This is a circuit topology diagram of a multi-phase parallel resonant converter that can automatically balance current provided in Example 1 of this patent.

[0014] Figure 2 This is a circuit topology diagram of a multi-phase parallel resonant converter that can automatically balance current provided in Example 2 of this patent.

[0015] Figure 3 is with Figure 1 Corresponding to the circuit topology of a conventional multi-phase parallel resonant converter that cannot achieve automatic current sharing, the resonant transformer has only a single secondary winding.

[0016] Figure 4 yes Figure 3 The simulated waveform of the resonant current of the two-phase unequal current.

[0017] Figure 5 yes Figure 1 The simulated waveform of the resonant current with two-phase equal current.

[0018] Figure 6 yes Figure 3 The simulation waveform of the rectified current with two-phase uneven current.

[0019] Figure 7 yes Figure 1 The simulation waveform of the rectified current with two-phase equal flow.

[0020] Figure 8 yes Figure 1 The experimental waveform of the resonant current with two-phase equal current.

[0021] Fig. 9 yes Figure 1 The experimental waveform of the two-phase equalized rectifier current.

[0022] Fig.10 yes Figure 3 The traditional resonant converter with only a single secondary winding and Figure 1 Parameters of the two-phase asymmetric resonant unit of the resonant converter with double secondary windings.

[0023] Fig.11 yes Fig.10 Under the asymmetric resonance unit parameters, Figure 3 The two-phase unbalanced resonant current of the traditional resonant converter with only a single secondary winding, and Figure 1 The patent discloses a two-phase balanced resonant current of a resonant converter with dual secondary windings.

[0024] Fig.12 yes Fig.10 Under the asymmetric unit parameters, Figure 3 The two-phase unbalanced rectified current of the traditional resonant converter with only a single secondary winding, and Figure 1 The patent discloses a two-phase balanced rectified current of a resonant converter with dual secondary windings.

[0025] In the figure, Phase1-the first branch of the multi-phase parallel resonant converter; S1-the first switch circuit; C1-the first resonant capacitor, L r1 - first resonant inductor, T1- first resonant transformer; N P1 - the primary winding of the first resonant transformer T1; N S11 、N S12 - Two secondary windings of the first resonant transformer T1; L m1 - connected in parallel to the primary winding N P1 The equivalent excitation inductance of the two ends a and b; R1-first rectifier circuit; 1-1-input port of the first switch circuit S1; 1-2-output port of the first switch circuit S1, 1-3-input port of the first rectifier circuit R1; 1-4-output port of the first rectifier circuit R1; C P1 - first parallel resonant capacitor; i Lr1 - the resonant current of the first branch; i rect1 - rectified current of the first branch;

[0026] Phase2-the second branch of the multi-phase parallel resonant converter; S2-the second switch circuit; C2-the second resonant capacitor, L r2 - second resonant inductor, T2- second resonant transformer; N P2 - the primary winding of the second resonant transformer T2; N S21 、N S22 - Two secondary windings of the second resonant transformer T2; L m2 - connected in parallel to the primary winding N P2 The equivalent excitation inductance at both ends g and h; R2-the second rectifier circuit; 2-1-the input port of the second switch circuit S2; 2-2-the output port of the second switch circuit S2, 2-3-the input port of the second rectifier circuit R2; 2-4-the output port of the second rectifier circuit R2; C P2 - second parallel resonant capacitor; i Lr2 - the resonant current of the second branch; i rect2 - The rectified current of the second branch. DETAILED DESCRIPTION

[0027] The core idea of ​​this patent is to divide the secondary windings of the two resonant transformers of the multi-phase parallel resonant converter into two respectively, connect the first secondary winding of the first resonant transformer and the first secondary winding of the second resonant transformer in series, and then connect them to the input port of the first rectifier circuit; connect the second secondary winding of the first resonant transformer and the second secondary winding of the second resonant transformer in series, and then connect them to the input port of the second rectifier circuit, so as to ensure that the total secondary currents of the first resonant transformer and the second resonant transformer are equal, thereby ensuring that the primary current of the first resonant transformer and the primary current of the second resonant transformer are equal, and ensuring that the output current of the first rectifier and the output current of the second rectifier are equal, so as to realize automatic balancing of the branch currents of the multi-phase parallel resonant converter.

[0028] The following is a clear and complete description of the technical solutions in the embodiments of this patent in conjunction with the drawings in the embodiments of this patent. Obviously, the described embodiments are only part of the embodiments of this patent, not all of them. Based on the core ideas and embodiments of this patent, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of this patent.

[0029] In order to fully understand the present patent, many specific details are mentioned in the following detailed description, but those skilled in the art should understand that the present patent can be implemented without these specific details.

[0030] Embodiment 1:

[0031] Refer to the attached Figure 1, a multi-phase parallel resonant converter capable of automatically balancing current, comprising:

[0032] The first phase resonant converter Phase1 includes a first switch circuit S1, a first resonant capacitor C1, a first resonant inductor L r1 , the first resonant transformer T1, the primary winding N connected in parallel to the first resonant transformer T1 P1 The first equivalent excitation inductance L at both ends a and b m1 , a first rectifier circuit R1; the first resonant capacitor C1, the first resonant inductor L r1 The first resonant transformer T1 is connected in series to form a first resonant unit; the first switch circuit S1 has an input port 1-1 and an output port 1-2, and the first rectifier circuit R1 has an input port 1-3 and an output port 1-4.

[0033] The second phase resonant converter Phase2 includes a second switch circuit S2, a second resonant capacitor C2, a second resonant inductor L r2 , the second resonant transformer T2, the primary winding N connected in parallel to the second resonant transformer T2 P2 The second equivalent excitation inductance L at both ends g and h m2 , a second rectifier circuit R2; the second resonant capacitor C2, the second resonant inductor L r2 The second resonant transformer T2 is connected in series to form a second resonant unit; the second switch circuit S2 has an input port 2-1 and an output port 2-2, and the second rectifier circuit R2 has an input port 2-3 and an output port 2-4.

[0034] The first resonant transformer T1 has two identical secondary windings N S11 and N S12 The second resonant transformer T2 has two identical secondary windings N S21 and N S22 The secondary winding N S11 and N S21 phases are connected in series and then connected to the input ports 1-3 of the first rectifier circuit R1; the secondary winding N S12 and N S22 The phases are connected in series and then connected to the input ports 2-3 of the second rectifier circuit R2, forming a multi-phase parallel LLC resonant converter that can automatically balance the current.

[0035] The two identical secondary windings refer to two secondary windings having the same structure, the same number of turns, the same wire shape, and the same wire cross-sectional area.

[0036] The implementation effect of this embodiment is shown in the attached Figure 3-12 .

[0037] By the attached Fig.10 It can be seen that for the attached Figure 1 The transformer proposed in this patent has a circuit topology with two secondary windings and an attached Figure 3 The conventional transformer shown has a circuit topology with a secondary winding. When the resonant unit parameters C2 and L r2 , L m2 The parameters of the first phase resonant unit C1 and L are r1 , L m1 When increasing by 10%:

[0038] By the attached Figure 4 and attached Figure 5 It can be seen that the traditional circuit topology (attached Figure 3 ) of the two-phase resonant current i Lr1 、i Lr2 Circuit simulation waveform (attached Figure 4 ) is very different and very unbalanced; and the circuit topology proposed in this patent (attached Figure 1 ) of the two-phase resonant current i Lr1 、i Lr2 Circuit simulation waveform (attached Figure 5 ) is very small and very balanced. Fig.11 It can be seen that the traditional circuit topology (attached Figure 3 ) has a current sharing error of 55.8%, while the circuit topology proposed in this patent (attached Figure 1 )’s resonant current sharing error is only 5.3%.

[0039] By the attached Figure 6 and attached Figure 7 It can be seen that the traditional circuit topology (attached Figure 3 ) of the two-phase rectified current i rect1 、i rect2 The simulation waveform (attached Figure 6 ) is very different, in which the first phase bears all the rectified current, while the second phase has no rectified current, which is very unbalanced; and the circuit topology proposed in this patent (attached Figure 1 ) of the two-phase rectified current i rect1 、i rect2 The simulation waveform (attached Figure 7 ) are exactly the same and very balanced. Fig.12 It can be seen that the traditional circuit topology (attached Figure 3 ) has a current sharing error of 100%, while the circuit topology proposed in this patent (attached Figure 1 )’s rectified current sharing error is 0.

[0040] The above circuit simulation (attached Figure 4-7 ) verified the implementation effect of Example 1.

[0041] By the attached Figure 8 It can be seen that the circuit topology proposed in this patent (attached Figure 1 ) of the two-phase resonant current i Lr1 、i Lr2 The experimental waveforms are very different and very balanced.

[0042] By the attached Fig. 9 It can be seen that the circuit topology proposed in this patent (attached Figure 1 ) of the two-phase rectified current i rect1 、i rect2 The experimental waveforms are very different and very balanced.

[0043] The above experiments were carried out on the experimental prototype (see Appendix Figure 8-9 ) verified the implementation effect of Example 1.

[0044] Embodiment 2:

[0045] Refer to the attached Figure 2 , a multi-phase parallel resonant converter with automatic current sharing, Figure 1 The first equivalent excitation inductance L m1 Replaced by the first parallel resonant capacitor C P1 , the second equivalent excitation inductance L m2 Replaced by the second parallel resonant capacitor C P2 , forming a multi-phase parallel LCC resonant converter that can automatically balance the current.

[0046] The above-mentioned embodiments are only preferred embodiments of this patent and are not intended to limit the scope of protection of this patent. The above-mentioned multiple embodiments are used in this specification to describe the principles and implementation methods of this patent, which are only used to help understand the methods and core ideas of this patent; at the same time, for those skilled in the art, the specific implementation methods and application scopes may be changed according to the ideas of this patent. Therefore, the content of this specification should not be understood as a limitation on this patent. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this patent are included in the scope of protection of this patent.

Claims

1. A multi-phase parallel resonant converter capable of automatically balancing current, comprising: The first phase resonant converter Phase1 includes a first switch circuit S1, a first resonant capacitor C1, a first resonant inductor L r1 , the first resonant transformer T1, the primary winding N connected in parallel to the first resonant transformer T1 P1 The first equivalent excitation inductance L at both ends a and b m1 , a first rectifier circuit R1; the first resonant capacitor C1, the first resonant inductor L r1 and the first resonant transformer T1 are connected in series to form a first resonant unit; the first switch circuit S1 has an input port 1-1 and an output port 1-2, and the first rectifier circuit R1 has an input port 1-3 and an output port 1-4; The second phase resonant converter Phase2 includes a second switch circuit S2, a second resonant capacitor C2, a second resonant inductor L r2 , the second resonant transformer T2, the primary winding N connected in parallel to the second resonant transformer T2 P2 The second equivalent excitation inductance L at both ends g and h m2 , a second rectifier circuit R2; the second resonant capacitor C2, the second resonant inductor L r2 The second resonant transformer T2 is connected in series to form a second resonant unit; the second switch circuit S2 has an input port 2-1 and an output port 2-2, and the second rectifier circuit R2 has an input port 2-3 and an output port 2-4; Features: The first resonant transformer T1 has two identical secondary windings N S11 and N S12 The second resonant transformer T2 has two identical secondary windings N S21 and N S22 The secondary winding N S11 and N S21 phases are connected in series and then connected to the input ports 1-3 of the first rectifier circuit R1; the secondary winding N S12 and N S22 The phases are connected in series and then connected to the input ports 2-3 of the second rectifier circuit R2, forming a multi-phase parallel LLC resonant converter that can automatically balance the current.

2. A multi-phase parallel resonant converter capable of automatic current sharing according to claim 1, characterized in that: The first excitation inductor L of the first resonant transformer T1 m1 Replaced by the first parallel resonant capacitor C P1 , the second excitation inductor L of the second resonant transformer T2 m2 Replaced by the second parallel resonant capacitor C P2 , forming a multi-phase parallel LCC resonant converter that can automatically balance the current.

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