Resonant power converter

Abstract

A resonant power converter includes a primary-side circuit and a secondary-side circuit. The secondary-side circuit includes multiple secondary-side windings and the same number of synchronous rectifier switches. The synchronous rectifier switches are respectively connected to the multiple secondary-side windings, forming a fractional-turn winding structure. This disclosure improves the power performance of the resonant power converter under high-current heavy-load conditions by having multiple fractional-turn secondary-side windings and configuring a corresponding number of synchronous rectifier switches, thereby effectively shortening the conductor length of the secondary-side windings, reducing winding resistance and corresponding conduction losses.

Description

Technical Field

[0001] This disclosure relates to a resonant power converter, and more particularly to a non-isolated resonant power converter with a fractional-turn winding architecture suitable for high-current applications. Background Technology

[0002] With the rapid development of cloud computing, artificial intelligence, and high-power server systems, data centers are increasingly demanding power converters with high efficiency, high power density, and high current output. For example, data center servers typically use bus voltages from 48V to 60V; therefore, resonant power converters with a fixed conversion ratio are widely used in high-power power architectures such as 48V to 12V or 48V to 6V.

[0003] In the prior art, resonant circuits with hybrid switched capacitors (HSCs) are frequently used in high-power power conversion applications due to their advantages such as soft switching and better conversion efficiency. However, in order to achieve a specific fixed conversion ratio, the secondary winding of existing HSC resonant topologies usually needs to have a high number of turns, which increases the wire length of the secondary winding and thus results in higher winding losses.

[0004] Furthermore, under high current operating conditions, the winding losses of the secondary winding often account for a considerable proportion of the overall converter losses, and due to the limited heat dissipation path of the winding, the winding heating problem can also easily become a major bottleneck limiting the improvement of power density.

[0005] How to gradually reduce the winding loss of the secondary winding while maintaining the existing fixed conversion ratio and control architecture is an important issue that needs to be addressed by those skilled in the art. Summary of the Invention

[0006] This disclosure provides a resonant power converter. The resonant power converter includes a primary-side circuit and a secondary-side circuit. The primary-side circuit is coupled to the input terminal. The secondary-side circuit is coupled to the output terminal and magnetically coupled to the primary-side circuit. The secondary-side circuit includes four secondary-side windings and four synchronous rectifier switches. The four secondary-side windings include a first secondary-side winding, a second secondary-side winding, a third secondary-side winding, and a fourth secondary-side winding. The corresponding terminals of the first and second secondary-side windings are located on a first side, and the corresponding terminals of the third and fourth secondary-side windings are located on a second side, with the first and second sides being opposite sides. The first to fourth synchronous rectifier switches are respectively connected to the first to fourth secondary-side windings, so that the four secondary-side windings together form a fractional-turn winding structure.

[0007] In some embodiments, the resonant power converter is a non-isolated resonant power converter.

[0008] In some embodiments, the primary-side circuit includes a first primary-side winding, a second primary-side winding, and a plurality of primary-side switches.

[0009] In some embodiments, the primary-side circuit further includes two resonant capacitors, which are cross-connected to the first primary-side winding and the second primary-side winding, respectively, to form a hybrid switched capacitor architecture.

[0010] In some embodiments, the first primary winding and the second primary winding have a first number of turns; and the first to the fourth secondary windings have a second number of turns different from the first number of turns.

[0011] In some embodiments, the first number of turns is 1 turn, and the second number of turns is 0.5 turns.

[0012] In some embodiments, a fixed conversion ratio between an input voltage at the input terminal and an output voltage at the output terminal is 8:1.

[0013] In some embodiments, the resonant power converter operates alternately in a first half-cycle and a second half-cycle; during the first half-cycle, a first switch and a fourth switch, a first synchronous rectifier switch and a third synchronous rectifier switch among the primary-side switches are in a conducting state; during the second half-cycle, a second switch and a third switch, a second synchronous rectifier switch and a fourth synchronous rectifier switch among the primary-side switches are in the conducting state.

[0014] In some embodiments, during the first half-cycle and the second half-cycle, a plurality of switches in the primary-side switches that are in the on state have a first peak current; the first primary-side winding and the second secondary-side winding have a second peak current, and the second peak current is twice the first peak current; and the third secondary-side winding has a third peak current during the first half-cycle, while the fourth secondary-side winding has the third peak current during the second half-cycle, and the third peak current is four times the first peak current.

[0015] In some embodiments, the first secondary winding and the second secondary winding each have a full-wave current waveform in the first half-cycle and the second half-cycle, and the full-wave current waveform has the second peak current; and the third secondary winding and the fourth secondary winding each have two discontinuous half-wave current waveforms.

[0016] In summary, this disclosure improves the power performance of the resonant power converter under high current heavy load conditions by having the secondary side circuit have multiple fractional-turn secondary side windings and configuring a corresponding number of synchronous rectifier switches to effectively shorten the wire length of the secondary side windings, reduce the winding resistance and corresponding conduction losses. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system architecture of a resonant power converter according to an embodiment of this disclosure.

[0018] Figure 2A Based on Figure 1 A schematic diagram of the layout of a primary winding in an embodiment.

[0019] Figure 2B Based on Figure 1 A schematic diagram of the layout of another primary winding in an embodiment.

[0020] Figure 2C Based on Figure 1 A schematic diagram of the secondary winding layout in an embodiment.

[0021] Figure 3A Based on Figure 1 A schematic diagram of the current flow of each component in the resonant power converter of the embodiment.

[0022] Figure 3B Based on Figure 3A The current waveforms of each component of the resonant power converter in the embodiment are shown in different half-cycles.

[0023] List of reference numerals

[0024] 100: Resonant Power Converter

[0025] Vin: Input voltage

[0026] Vo: Output voltage

[0027] N1: Primary side circuit

[0028] N2: Secondary side circuit

[0029] S1, S2, S3, S4: Primary side switches

[0030] Cr1, Cr2: Resonant capacitors

[0031] Np1, Np2: Primary windings

[0032] Ns1, Ns2, Ns3, Ns4: Secondary windings

[0033] S5, S6, S7, S8: Synchronous rectifier switches

[0034] Lr1, Lr2: Equivalent resonant inductance

[0035] i, -i: First peak current

[0036] 2i: Second peak current

[0037] 3i: Third peak current

[0038] 4i: Fourth peak current

[0039] HP1, HP2: Half-cycle Detailed Implementation

[0040] The embodiments of this disclosure will be described below with reference to the relevant drawings. In the drawings, the same reference numerals denote the same or similar elements or method flows.

[0041] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the system architecture of a resonant power converter 100 according to an embodiment of this disclosure. The resonant power converter 100 may include a primary-side circuit N1 and a secondary-side circuit N2. The primary-side circuit N1 is coupled to an input terminal. The secondary-side circuit N2 is coupled to an output terminal and is magnetically coupled to the primary-side circuit N1.

[0042] Incidentally, in Figure 1 In some embodiments, the resonant power converter 100 may be configured as a non-isolated resonant power converter.

[0043] The primary-side circuit N1 includes primary-side windings Np1 and Np2, primary-side switches S1, S2, S3, and S4, and resonant capacitors Cr1 and Cr2. The resonant capacitors Cr1 and Cr2 can be cross-connected to the first primary-side winding Np1 and the second primary-side winding Np2, respectively, so that the primary-side circuit N1 constitutes a hybrid switched-capacitor (HSC) architecture.

[0044] In this embodiment, the primary winding Np1 and the primary winding Np2 have the same number of turns, for example, 1 turn.

[0045] The secondary-side circuit N2 includes four secondary-side windings and four synchronous rectifier switches. More specifically, the four secondary-side windings include secondary-side windings Ns1, Ns2, Ns3, and Ns4; and the four synchronous rectifier switches include synchronous rectifier switches S5, S6, S7, and S8.

[0046] Synchronous rectifier switch S5 is connected to the secondary winding Ns1; synchronous rectifier switch S6 is connected to the secondary winding Ns2; synchronous rectifier switch S7 is connected to the secondary winding Ns3; synchronous rectifier switch S8 is connected to the secondary winding Ns4.

[0047] Furthermore, the corresponding terminals of the secondary winding Ns1 ( Figure 1 The black dot marking in the lower right corner of “Ns1” and the corresponding terminal of the secondary winding Ns2 are located on the first side; conversely, the corresponding terminals of the secondary winding Ns3 and the secondary winding Ns4 are located on the second side. The first side and the second side are opposite sides (for example, located at opposite ends of the winding coils).

[0048] Furthermore, in this embodiment, the secondary windings Ns1, Ns2, Ns3, and Ns4 have the same number of turns, for example, 0.5 turns. Therefore, it can be seen that the number of turns in the secondary windings is different from the number of turns in the primary windings described above.

[0049] With the above-described circuit component configuration, Figure 1 The secondary windings Ns1 to Ns4 can together form a fractional-turn winding structure when the resonant power converter 100 is in operation.

[0050] Under this electrical coupling relationship where the primary windings Np1 and Np2 each have 1 turn and the secondary windings Ns1 to Ns4 each have 0.5 turns, the resonant power converter 100 can maintain a specific fixed conversion ratio between the input voltage Vin at the input terminal and the output voltage Vo at the output terminal. The fixed conversion ratio can be equal to 8:1, thus making it suitable for high-power applications such as data centers that require large current step-down.

[0051] Furthermore, due to Figure 1 The secondary windings Ns1 to Ns4 employ a fractional-turn winding architecture and are equipped with corresponding synchronous rectifier switches S5, S6, S7, and S8. This effectively shortens the wire length of each secondary winding, reduces winding resistance and corresponding conduction losses, thereby significantly improving the power performance of the resonant power converter 100 under high-current heavy load conditions. In some embodiments, the resonant power converter 100 can save 26% of power consumption compared to conventional resonant power converters, but the power consumption ratio disclosed herein is not limited to this.

[0052] Please refer to the following at the same time Figure 1 , Figure 2A , Figure 2A Based on Figure 1 A schematic diagram of the layout of a primary winding NP1 in an embodiment. Figure 2A The magnetic core of the transformer and the physical wiring structure of the primary winding Np1 of the resonant power converter 100 are revealed.

[0053] like Figure 2A As shown, the magnetic core can be type E, EE, or EI, and it includes a central post and side posts on both sides. The primary winding Np1 (in...) Figure 2A The circuit (represented by a thick solid line) can be mounted on a printed circuit board. One end of the circuit (the same-name end, marked with a black dot) is connected in series with the resonant capacitor Cr1 and the equivalent resonant inductance Lr1, and coupled to the common contact between the primary-side switches S1 and S3. The physical trace of the primary-side winding Np1 starts from the same-name end, passes down through the window on the right side of the core, crosses below the central post, passes up through the window on the left side of the core, crosses the area above the central post and extends to the right, finally coupling to the primary-side switch S4.

[0054] By using a physical trace that is completely wound around the central post of the magnetic core, the primary winding Np1 can be precisely constructed to have 1 turn in its physical structure.

[0055] Figure 2A The diagram further illustrates the physical winding direction and current path of the primary winding Np1 when the primary side switches S1 and S4 are on while the primary side switches S2 and S3 are off, following the direction of the arrows indicating the winding.

[0056] The above winding layout can effectively utilize the space of the printed circuit board to realize the hardware foundation for the cross-connection required on the primary side of the HSC architecture.

[0057] Please refer to the following at the same time Figure 1 , Figure 2B , Figure 2B Based on Figure 1A schematic diagram of the layout of another primary winding NP2 in the embodiment. Figure 2B The magnetic core of the transformer and the physical wiring structure of the primary winding Np2 of the resonant power converter 100 are revealed.

[0058] like Figure 2B As shown, the primary winding Np2 (in Figure 2B The primary winding (represented by a thick solid line) can also be mounted on a printed circuit board. One end (the same-name end, marked with a black dot) is coupled to the primary-side switch S3, and the other end (the non-same-name end) is connected in series with the resonant capacitor Cr2 and the equivalent resonant inductance Lr2, and coupled to the common connection point between the primary-side switches S2 and S4. The physical trace of the primary-side winding Np2 starts from the same-name end, goes down through the window on the right side of the core, crosses below the central post, goes up through the window on the left side of the core, then extends to the left across the area above the central post, and finally couples to the common connection point between the primary-side switches S2 and S4.

[0059] By using a physical trace that is completely wound around the central post of the magnetic core, the primary winding Np2 can also be precisely constructed to have 1 turn in terms of physical structure.

[0060] Figure 2B The diagram further illustrates the physical winding direction and current path of the primary winding Np2 when the primary side switches S2 and S3 are on while the primary side switches S1 and S4 are off, following the direction of the arrows indicating the winding.

[0061] Cooperate Figure 2A The corresponding configuration of the primary winding Np1, and the primary windings Np1 and Np2 can realize the hardware design of primary resonant cross connection in HSC architecture in terms of physical wiring.

[0062] Please refer to the following at the same time Figure 1 , Figure 2C , Figure 2C Based on Figure 1 A schematic diagram of the secondary windings Ns1, Ns2, Ns3 and Ns4 in the embodiment. Figure 2C The physical wiring method of the secondary windings Ns1, Ns2, Ns3 and Ns4 in the core of the transformer of the resonant power converter 100 is revealed.

[0063] like Figure 2CAs shown, the secondary windings Ns1, Ns2, Ns3, and Ns4 are composed of multiple metal pattern layers disposed on a printed circuit board. Unlike the primary windings Np1 and Np2, which completely encircle the central column of the magnetic core, the secondary windings Ns1, Ns2, Ns3, and Ns4 physically pass through the side window of the magnetic core only once. Specifically, secondary windings Ns1 and Ns4 pass through the window on the left side of the magnetic core in a straight or semi-circular shape; while secondary windings Ns2 and Ns3 pass through the window on the right side of the magnetic core. This design, where the secondary windings pass through a single window without completely encircling the central column, allows the secondary windings Ns1 to Ns4 to form fractional-turn windings of less than one turn. More precisely, it allows the secondary windings Ns1 to Ns4 to physically form a number of turns of 0.5 (e.g., ...). Figure 2C The values ​​marked "Ns1=0.5", "Ns2=0.5", "Ns3=0.5" and "Ns4=0.5" are included.

[0064] In addition, such as Figure 2C As shown, the two ends of each secondary winding can be coupled to the output terminal and the corresponding synchronous rectifier switches S5 to S8, respectively. Figure 2C It also indicates the position of the corresponding terminals (black dots) of each secondary winding and coil.

[0065] This fractional-turn physical wiring architecture can significantly shorten the physical length of the secondary side traces, which can not only effectively reduce the DC resistance of the windings, but also reduce the proximity effect of the windings under high-frequency operation, thereby significantly reducing the AC resistance.

[0066] In addition, in coordination with the secondary windings Ns1 to Ns4 Figure 2C With this configuration, the resonant power converter 100 can significantly reduce the conduction losses of the secondary side circuit from both physical and electrical perspectives.

[0067] Please refer to the following at the same time Figure 1 , Figure 3A , Figure 3B . Figure 3A Based on Figure 1 A schematic diagram of the current flow of each component in the resonant power converter 100 of the embodiment. Figure 3B Based on Figure 3A The current waveforms of each component of the resonant power converter 100 in the embodiment during different half-cycles are shown.

[0068] To reduce the overall system control complexity and circuit drive cost, the synchronous rectifier switches S5 and S7 in the secondary side circuit N2 are designed to receive the same first drive signal; correspondingly, the synchronous rectifier switches S6 and S8 are designed to receive the same second drive signal.

[0069] More specifically, the first drive signal and the second drive signal have specific waveform and timing characteristics. The first drive signal and the second drive signal may be a set of alternating and complementary pulse signals (e.g., square wave or pulse wave signals), and there may be a phase difference of 180 degrees (i.e., half an operating cycle) between the first drive signal and the second drive signal.

[0070] In some embodiments, to ensure symmetrical operation and optimize power transfer efficiency, the duty cycle of both the first drive signal and the second drive signal is close to 50%. Furthermore, the timing characteristics of the first and second drive signals are highly dependent on the switching timing of the primary-side circuit. Specifically, the conduction period of the first drive signal is synchronized with the conduction timing of the primary-side switches S1 and S4; while the conduction period of the second drive signal is synchronized with the conduction timing of the primary-side switches S2 and S3.

[0071] Through the interleaved enabling characteristics of the first and second driving signals, the resonant power converter 100 can achieve the driving state of the four secondary windings (secondary windings Ns1 to Ns4) without adding additional control chip pins.

[0072] like Figure 3B As shown, half-cycles HP1 and HP2 can be operated together for one operating cycle. In the embodiments disclosed herein, the various elements of the resonant power converter 100 can operate alternately during half-cycles HP1 and / or HP2.

[0073] During half-cycle HP1, primary-side switches S1 and S4 in the primary-side circuit N1 are turned on based on the first drive signal, and primary-side current flows from primary-side switch S1 to primary-side windings Np1 and Np2; simultaneously, synchronous rectifier switches S5 and S7 in the secondary-side circuit N2 are also switched on accordingly. Primary-side switches S2 and S3 and synchronous rectifier switches S6 and S8 are not turned on.

[0074] Next, during half-cycle HP2, primary-side switches S2 and S3 in the primary-side circuit N1 are turned on based on the second drive signal, and primary-side current flows from primary-side switch S2 to primary-side windings Np1 and Np2; simultaneously, synchronous rectifier switches S6 and S8 in the secondary-side circuit N2 are also turned on. Primary-side switches S1 and S4 and synchronous rectifier switches S5 and S7 are not turned on.

[0075] Figure 3A The arrows next to each component clearly indicate the current direction of each component in the primary winding and secondary winding under the above alternating switching sequence.

[0076] Further observation Figure 3B As can be seen from the current waveform shown in the figure, the fractional-turn winding architecture of this embodiment has a unique current amplitude ratio.

[0077] In half-cycles HP1 and HP2, multiple primary-side switches (e.g., primary-side switches S1 / S4 or primary-side switches S2 / S3) in the on state have a first peak current i.

[0078] In the primary-side circuit N1, the primary-side windings Np1 and Np2 carry continuous AC resonant currents. Specifically, as follows... Figure 3B The primary winding Np1 has a first peak current i during half-cycle HP1 and a reverse first peak current -i during half-cycle HP2. Correspondingly, the primary winding Np2 has a reverse first peak current -i during half-cycle HP1 and a first peak current i during half-cycle HP2. Therefore, the current waveforms of the primary winding Np1 and Np2 are continuous sine waves with a 180-degree phase difference.

[0079] In the secondary side circuit N2, the secondary side windings Ns1 and Ns2 together have a second peak current 2i, and the second peak current 2i is exactly twice the first peak current i.

[0080] Synchronous rectifier switch S5 has a third peak current 3i during half-cycle HP1, and synchronous rectifier switch S6 also has a third peak current 3i during alternating half-cycle HP2, and the third peak current 3i is three times the first peak current i.

[0081] On the other hand, the secondary winding Ns3 has a fourth peak current 4i during half-cycle HP1, and the secondary winding Ns4 also has a fourth peak current 4i during alternating half-cycle HP2, and the fourth peak current 4i is four times the first peak current i.

[0082] Regarding the continuity characteristics of the current waveform, such as Figure 3B As shown, the currents flowing through the primary windings Np1 and Np2 are complete and continuous sinusoidal resonant current waveforms. When the primary energy is coupled to the secondary side via the magnetic core, current flows through the secondary windings Ns1 and Ns2 during half-cycles HP1 and HP2, thus forming a continuous full-wave current waveform. The maximum amplitude of this full-wave current waveform is the aforementioned second peak current 2i. Correspondingly, the secondary windings Ns3 and Ns4 are restricted by the alternating conduction of the synchronous rectifier switches S7 and S8, and therefore have discontinuous half-wave current waveforms (i.e., the current pulse wave of the secondary winding Ns3 only appears in half-cycle HP1, while the current pulse wave of the secondary winding Ns4 only appears in half-cycle HP2).

[0083] By employing this mechanism of "partial winding full-wave operation to share the base current and partial winding half-wave operation to share the instantaneous large current," the resonant power converter 100 can solve the problem of a single winding bearing extremely large current in traditional HSC circuits, properly shunting the large current and thus significantly reducing the overall conduction loss on the secondary side.

[0084] It should be added that, Figure 3B The current multiple relationships disclosed herein (i.e., the ratio of the first peak current i, the second peak current 2i, the third peak current 3i, and the fourth peak current 4i) depend on the charging and discharging behavior of the resonant capacitors Cr1 and Cr2 in the primary-side circuit N1 and the changes in the current values ​​of the primary-side windings Np1 and Np2, and are related to... Figure 2C The physical geometry layout of the secondary windings Ns1 to Ns4 shown is closely related.

[0085] In detail, when the resonant power converter 100 operates alternately through multiple half-cycles HP1 and HP2, the alternating switching of the primary-side switches drives the resonant capacitors Cr1 and Cr2 to perform periodic charging and discharging behavior. The electrical energy generated by the charging and discharging of the capacitors can be magnetically coupled to the secondary-side circuit N2 via the transformer. According to the transformer's ampere-turn balance principle, since the number of turns in the secondary-side winding is less than the number of turns in the primary-side winding, the current reflected to the secondary side is amplified. In this embodiment, there is a current transformation ratio of 1:0.5 between the primary-side winding and the secondary-side winding, thereby amplifying the basic reflected current to the secondary side to twice the first peak current i, which is the second peak current 2i presented on the secondary-side windings Ns1 and Ns2.

[0086] Incidentally, during half-cycle HP1, resonant capacitor Cr1 charges and resonant capacitor Cr2 discharges, in conjunction with... Figure 2C The low-impedance path formed by the secondary winding Ns3 and the synchronous rectifier switch S7 allows the peak current of the secondary winding Ns3 to be higher than the peak currents of the secondary windings Ns1 and Ns2. During half-cycle HP2, resonant capacitor Cr1 discharges and resonant capacitor Cr2 charges, in conjunction with... Figure 2C The low-impedance path formed by the secondary winding Ns4 and the synchronous rectifier switch S8 will cause the peak current of the secondary winding Ns4 to increase to four times the first peak current i (the fourth peak current 4i).

[0087] In summary, the current multiplier relationship disclosed in this document is the result of the combined effect of the charging and discharging behavior of the resonant capacitors Cr1 and Cr2 in the primary side circuit N1 and the geometric layout of the 0.5-turn fractional-turn winding in the secondary side physical space.

[0088] Compared to the conventional HSC resonant circuit which uses only two secondary windings, the resonant power converter 100 disclosed in this document further splits the secondary winding into four fractional-turn secondary windings, and forms corresponding conduction paths with additional synchronous rectifier switches. In this way, the resonant power converter 100 can effectively shorten the wire length of the secondary winding while maintaining a fixed conversion ratio, reducing winding resistance and corresponding conduction losses, and improving the power performance of the resonant circuit under high current heavy load conditions.

[0089] The above are merely preferred embodiments of this disclosure. Various modifications and equivalent changes can be made to this disclosure without departing from its scope or spirit. In summary, all modifications and equivalent changes to this disclosure made within the scope of the following claims are within the scope of this disclosure.

Claims

1. A resonant power converter, characterized in that, This resonant power converter includes: A primary-side circuit coupled to an input terminal; and A secondary-side circuit is coupled to an output terminal and magnetically coupled to the primary-side circuit. The secondary-side circuit includes: Four secondary windings, including a primary winding, a secondary winding, a tertiary winding, and a fourth secondary winding; and Four synchronous rectifier switches, including a first synchronous rectifier switch, a second synchronous rectifier switch, a third synchronous rectifier switch and a fourth synchronous rectifier switch; Wherein, the same-named end of the first secondary winding and the same-named end of the second secondary winding are disposed on a first side, and the same-named end of the third secondary winding and the same-named end of the fourth secondary winding are disposed on a second side, and the first side and the second side are opposite sides. The first synchronous rectifier switch to the fourth synchronous rectifier switch are respectively connected to the first secondary winding to the fourth secondary winding, so that the four secondary windings together form a fractional-turn winding structure.

2. The resonant power converter as described in claim 1, characterized in that, This resonant power converter is a non-isolated resonant power converter.

3. The resonant power converter as described in claim 1, characterized in that, The primary-side circuit includes a first primary-side winding, a second primary-side winding, and multiple primary-side switches.

4. The resonant power converter as described in claim 3, characterized in that, The primary-side circuit further includes two resonant capacitors, which are cross-connected to the first primary-side winding and the second primary-side winding, respectively, to form a hybrid switched capacitor architecture.

5. The resonant power converter as described in claim 4, characterized in that, The first primary winding and the second primary winding have a first number of turns; and The first secondary winding to the fourth secondary winding has a second number of turns that is different from the first number of turns.

6. The resonant power converter as described in claim 5, characterized in that, The first number of turns is 1 turn, and the second number of turns is 0.5 turns.

7. The resonant power converter as described in claim 6, characterized in that, The fixed conversion ratio between an input voltage at the input terminal and an output voltage at the output terminal is 8:

1.

8. The resonant power converter as described in claim 7, characterized in that, The resonant power converter operates alternately in a first half-cycle and a second half-cycle. During the first half-cycle, a first switch and a fourth switch among the primary side switches, the first synchronous rectifier switch and the third synchronous rectifier switch are in a conducting state; During the second half-cycle, a second switch, a third switch, a second synchronous rectifier switch, and a fourth synchronous rectifier switch among the primary side switches are in the on state.

9. The resonant power converter as described in claim 8, characterized in that, During the first half-cycle and the second half-cycle, a plurality of the primary-side switches in the on state have a first peak current. The first stage winding and the second stage winding have a second peak current, and the second peak current is twice the first peak current; as well as The third secondary winding has a third peak current during the first half-cycle, and the fourth secondary winding has the third peak current during the second half-cycle, and the third peak current is four times the first peak current.

10. The resonant power converter as described in claim 9, characterized in that, The first stage winding and the second stage winding both have a full-wave current waveform in the first half-cycle and the second half-cycle, and the full-wave current waveform has the second peak current. as well as The third secondary winding and the fourth secondary winding each have two discontinuous half-wave current waveforms.

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