Resonant converter and power supply assembly comprising same

Abstract

The invention relates to a resonant converter comprising a plurality of input ports, a plurality of conversion circuits, and an output port, each conversion circuit comprising: an inverter bridge connected to a respective one of the plurality of input ports, the converter is configured to convert a direct current input signal received from the corresponding input port into a high-frequency alternating current signal; the resonance circuit is configured to generate a corresponding resonance signal based on the high-frequency alternating current signal received from the inverter bridge; a transformer configured to perform an isolation transformation operation on the resonance signal output by the resonance circuit and output a changed transformation signal; and the rectifier bridge is configured to convert a transformation signal provided by the transformer into a direct current output signal again, the resonant converter further comprises a capacitor network formed by at least one capacitor, and the capacitor is arranged at any position in a primary side loop of the conversion circuit. The invention also relates to a power supply assembly comprising the resonant converter.

Description

Technical Field

[0001] This invention relates to the field of converters, and more specifically, to a resonant converter and a power supply assembly including the resonant converter. Background Technology

[0002] With the rapid development of new energy vehicle technology, the demand for efficient and high-density power conversion equipment is increasing. Existing DC / DC converters in electric vehicles can be used to convert the energy of high-voltage batteries into the electrical energy required by low-voltage loads. However, existing technologies have many limitations when handling the series and parallel switching of multiple high-voltage batteries, such as voltage balance issues, power outage risks, and compatibility issues with wide input voltage ranges. These problems not only affect the performance and reliability of electric vehicles but also limit their potential in terms of energy efficiency and driving range.

[0003] Furthermore, electric vehicles have varying energy demands under different operating conditions, requiring DC / DC converters to flexibly adapt to these diverse energy conversion needs. Existing DC / DC converter designs often struggle to simultaneously meet multiple requirements, including a wide input voltage range, high efficiency, and good voltage stability. Especially when multiple high-voltage battery banks need to be connected in series and parallel for switching to accommodate different charging infrastructures, achieving efficient and stable power conversion becomes a new technological challenge. Summary of the Invention

[0004] The present invention aims to provide a novel multi-port resonant converter topology and its construction method to solve the problems existing in the prior art and achieve a wide voltage gain range and high conversion efficiency.

[0005] A first aspect of the present invention provides a resonant converter, the resonant converter including a plurality of input ports, a plurality of conversion circuits, and an output port, each conversion circuit being connected to a corresponding group of DC power supplies from a plurality of DC power supplies via a corresponding input port of the plurality of input ports, and connected to an external load via the output port, characterized in that each conversion circuit includes:

[0006] An inverter bridge is connected to a corresponding input port among the plurality of input ports and is configured to convert a DC input signal received from the corresponding input port into a high-frequency AC signal.

[0007] A resonant circuit configured to generate a corresponding resonant signal based on a high-frequency AC signal received from the inverter bridge;

[0008] A transformer configured to perform an isolation transformation operation on a resonant signal output from the resonant circuit to change the voltage level of the resonant signal and output a modified transformed signal; and

[0009] A rectifier bridge is configured to convert the transformer signal provided by the transformer back into a DC output signal and provide the DC output signal to the output port of the resonant converter.

[0010] The resonant converter further includes a capacitor network consisting of at least one capacitor, which is disposed at any position in the primary loop of the conversion circuit.

[0011] According to an optional embodiment, the inverter bridge includes a high-side input terminal connected to the positive terminal of a corresponding set of DC power supplies in the plurality of sets of DC power supplies, and a low-side input terminal connected to the negative terminal of the corresponding set of DC power supplies.

[0012] According to an alternative embodiment, the at least one capacitor is disposed between the high-side input or low-side input of one of the plurality of conversion circuits and the high-side input or low-side input of another of the plurality of conversion circuits.

[0013] According to an alternative embodiment, the at least one capacitor is disposed between the output terminal of a corresponding resonant circuit in the plurality of conversion circuits and the output terminal of another resonant circuit in the plurality of conversion circuits.

[0014] According to an optional embodiment, the capacitor network includes:

[0015] First public contact point; and

[0016] Multiple capacitors, each capacitor being connected between the low-side or high-side input of a corresponding inverter bridge in the multiple conversion circuits and the first common contact.

[0017] According to an optional embodiment, the capacitor network includes:

[0018] Second public contact point;

[0019] A plurality of first capacitors, each first capacitor being connected between the high-side input of a corresponding inverter bridge in the plurality of conversion circuits and the common contact; and

[0020] Multiple second capacitors, each second capacitor being connected between the low-side input terminals of a corresponding inverter bridge in the multiple conversion circuits at the common contact.

[0021] According to an alternative embodiment, the capacitor network includes a plurality of third capacitors, each third capacitor being connected between the low-side or high-side input of a corresponding inverter bridge in the plurality of conversion circuits and the high-side or low-side input of another inverter bridge in the plurality of conversion circuits.

[0022] According to an alternative embodiment, the resonant circuit includes an LLC resonator.

[0023] According to an optional embodiment, the capacitance value of the at least one capacitor in the capacitor network is set to be larger than the capacitance value of the capacitor in the LLC resonator.

[0024] A second aspect of the present invention also provides a power supply assembly, wherein the power supply assembly comprises:

[0025] Multiple DC power supplies, each configured to output a DC signal with a predetermined voltage value; and

[0026] The resonant converter as described above.

[0027] According to the multi-port resonant converter topology of the present invention, the voltage between each input port can float freely, making it suitable for applications where the voltage between each phase input power supply needs to float independently. Furthermore, this resonant inverter has a simple structure, few components, is easy to control, and has a wide voltage range gain and high conversion efficiency, making it particularly suitable for series-parallel switching schemes of multiple high-voltage batteries (or isolated power supplies) in electric vehicles. In addition, this resonant converter can reduce electromagnetic interference and improve the electromagnetic compatibility of the system, thereby significantly improving the overall performance and user experience of electric vehicles. This topology not only improves the flexibility and reliability of power conversion but also significantly enhances the efficiency and stability of the system. Attached Figure Description

[0028] Other features and advantages of the method of the invention will become clear or more specifically illustrated by incorporating the accompanying drawings and the specific embodiments which, together with the drawings, are used to illustrate certain principles of the invention.

[0029] Figure 1a A schematic diagram of a conventional parallel full-bridge LLC topology is shown.

[0030] Figure 1b A schematic diagram of a conventional series full-bridge LLC topology is shown.

[0031] Figure 2 A schematic diagram illustrating the basic working principle of a conventional resonant converter is shown.

[0032] Figure 3 Schematic diagrams of several topological variations of a resonant converter according to exemplary embodiments of the present invention are shown.

[0033] Figure 4 A schematic diagram of a first arrangement of the capacitor network in a resonant converter according to an exemplary embodiment of the present invention is shown;

[0034] Figure 5 A schematic diagram of a second arrangement of the capacitor network in a resonant converter according to an exemplary embodiment of the present invention is shown;

[0035] Figure 6 A schematic diagram of a third arrangement of the capacitor network in a resonant converter according to an exemplary embodiment of the present invention is shown;

[0036] Figure 7 A circuit diagram of a power supply assembly integrating a resonant converter according to the present invention is shown. Detailed Implementation

[0037] The resonant converter according to the present invention will now be described with reference to the accompanying drawings and embodiments. In the following description, numerous specific details are set forth to enable those skilled in the art to gain a more complete understanding of the invention. However, it will be apparent to those skilled in the art that implementation of the invention may not include some of these specific details. Instead, the invention may be conceived to be practiced with any combination of the following features and elements, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be construed as elements or limitations of the claims.

[0038] Currently, to improve charging speed, the voltage of vehicle high-voltage electrical systems is gradually increasing. However, many charging facilities on the market with voltages below 800V cannot support higher voltage charging. To ensure compatibility with existing low-voltage charging facilities, some vehicle manufacturers have provided solutions that achieve compatibility with both low-voltage and high-voltage fast charging equipment by switching between series and parallel connections of two battery banks. Simultaneously, to power low-voltage loads within the vehicle, a DC / DC converter is needed to transfer energy from the high-voltage battery to the low-voltage side.

[0039] However, this solution has the following drawbacks:

[0040] -If only one DC / DC converter is used to draw power from one of the high-voltage batteries, it will cause an imbalance in the voltage of the two high-voltage batteries;

[0041] - If a DC / DC converter is used to draw power from two sets of high-voltage batteries connected in series, the power supply will be interrupted when switching power sources. At this time, the converter needs to stop working. In addition, such a DC / DC converter needs to be compatible with an extremely wide input voltage range.

[0042] If two DC / DC converters are used to draw power from two sets of high-voltage batteries respectively, it is necessary to actively control the steady-state load balancing of the two DC / DC converters, and to optimize the transient dynamic performance of the low-voltage load after the two DC / DC converters are connected in parallel.

[0043] To address this, a DC / DC converter based on a resonant converter topology has been developed. In this topology, if each DC / DC converter uses a half-bridge topology with one phase arm, its input / output voltage gain range and efficiency potential are lower compared to a full-bridge topology. Therefore, two types of topologies have been developed: parallel full-bridge LLC and series full-bridge LLC, such as... Figure 1a and Figure 1b As shown in the diagram. However, when these two topologies are operating, the two phase arms of the converter need to be directly shorted, so the converter still needs to stop operating during battery switching, and there are electromagnetic compatibility issues due to the high-frequency resonant current flowing out of the DC / DC converter.

[0044] To address the problems encountered by existing DC / DC converters in vehicles during the switching of multiple high-voltage battery banks in series and parallel connections, this invention proposes a novel multi-port resonant converter topology. This resonant converter, by introducing a high-frequency current bypass capacitor network, achieves free voltage floating between each input port, thereby allowing independent switching between different input power supplies without considering the voltage state of other ports. This resonant converter can achieve a wide gain range and relatively high conversion efficiency with a minimal number of switching devices.

[0045] Before describing the internal structure of the resonant converter of the present invention, refer to... Figure 2 This describes the basic working principle of a conventional resonant converter topology. For example... Figure 2 As shown, a conventional resonant converter mainly consists of an inverter bridge, a resonant circuit, a transformer, and a rectifier bridge. The resonant converter first receives a DC input signal from an external power source. This input signal is then converted into a high-frequency AC voltage by the high-frequency switching operations of the bridge arm switching devices Q1 and Q2 in the inverter bridge. The high-frequency AC voltage generated by the inverter bridge then enters the resonant circuit, which consists of resonant inductors Lr and Lm and a resonant capacitor Cr. At the resonant frequency, the circuit impedance is minimized, and the energy transfer efficiency is highest. This resonant circuit reduces the switching losses of the switching devices in the inverter bridge and smooths the voltage and current waveforms, thereby generating high-frequency AC current and voltage. The high-frequency AC signal in the resonant circuit is further transmitted to the secondary winding through the primary winding of the transformer. The transformer changes the voltage level of the AC signal while providing electrical isolation. On the secondary side of the transformer, the output high-frequency AC voltage can be converted back to a DC output voltage by the rectifier bridge. This DC output voltage can ultimately be used to power or charge the target load in the vehicle.

[0046] Throughout the signal conversion process of a resonant converter, energy conversion efficiency can be optimized, switching losses reduced, and a stable output voltage provided. In particular, by precisely controlling switching action and utilizing the characteristics of the resonant circuit, the resonant converter can provide efficient and high-performance solutions for various power conversion applications.

[0047] After understanding the basic working principle of the resonant converter, refer to the following... Figures 3-6 Here are some examples illustrating several possible topologies of the resonant converter according to the present invention.

[0048] Figure 3 Topological schematic diagrams of several variations of a resonant converter according to exemplary embodiments of the present invention are shown. Figure 3 (a) shows the topology of a series full-bridge LLC resonant converter, which includes two DC / DC conversion circuits, each of which is connected to a separate external power supply, and the two conversion units are interconnected in series, especially their inverter bridges.

[0049] As is well known, a resonant converter can be divided into a primary circuit and a secondary circuit, with the transformer as the dividing line. The primary circuit refers to the circuit connected to the input power supply—that is, the circuit connected to the primary side of the transformer—and includes components such as the inverter bridge, resonant inductor, and resonant capacitor. The main function of the primary circuit is to control and regulate the flow of energy. Through the periodic switching of the switching devices in the inverter bridge, energy is stored in the resonant inductor and capacitor, and then transferred to the secondary winding of the transformer through the resonant circuit. The secondary circuit refers to the circuit connected to the secondary winding of the transformer, including the rectifier bridge and its downstream filter capacitors, loads, etc. The function of the secondary circuit is to receive the energy transferred from the transformer and provide it to the load after rectification and filtering. The secondary circuit usually also includes some protection and control circuits, such as overcurrent protection and short-circuit protection, to ensure the safe and stable operation of the system.

[0050] refer to Figure 3 In (a), C1, Q11, and Q12 form one inverter bridge, and C2, Q21, and Q22 form another inverter bridge. These two inverter bridges, together with resonant inductors Lr1 and Lr2, resonant capacitors Cr1 and Cr2, and the primary sides of transformers T1 and T2, constitute a high-frequency alternating current loop—the so-called "primary loop." In addition to the conventional structure described above, the resonant converter of this invention may also include a capacitor network consisting of at least one capacitor, which can be positioned at any location in the primary loop of the conversion circuit.

[0051] Figure 3Figure (b) shows a possible arrangement of the capacitor network, in which two capacitors CB1 and CB2 can be connected in series between the output terminals of the first resonant circuit and the second resonant circuit in the two conversion circuits. That is, in the high-frequency AC current loop, in addition to the original capacitors Cr1 and Cr2 in the resonant circuit, capacitors CB1 and CB2 can be added in series. As long as the capacitance of capacitors Cr1, CB1, Cr1, and CB2 after being connected in series remains unchanged from the capacitance before CB1 and CB2 are connected in series, the addition of CB1 and CB2 will not affect the original normal operation of this circuit. These two additional capacitors can be located anywhere in this high-frequency AC current loop. In order to utilize the DC blocking characteristics of the capacitors and allow the current to float freely between the two inverter bridges, these two capacitors can be placed between the connection points of the two bridge circuits, such as... Figure 3 As shown in (c) and (d) in the figure. Figure 3 Figures (c) and (d) show the cases where capacitors CB1 and CB2 are positioned between the low-side input of the first inverter bridge and the high-side input of the second inverter bridge, and between the low-side input of the first inverter bridge and the low-side input of the second inverter bridge, respectively. Other capacitor configurations are also conceivable, such as CB1 and CB2 connected in series between the high-side inputs of the two inverter bridges.

[0052] To prevent high-frequency AC current from flowing out of the converter topology, the capacitances of CB1 and CB2 are typically set to be significantly larger than the capacitances of resonant capacitors Cr1 and Cr2. This ensures that the AC voltage generated between the two bridge arms due to high-frequency switching is sufficiently small. Due to the presence of input-side bus capacitors C1 and C2, the connection of CB1 and CB2 to the positive and negative terminals of each phase bridge arm only affects the current waveform flowing through C1 and C2, and has no impact on the normal operation of the LLC resonant converter topology.

[0053] Understandable Figure 3 Although only two DC / DC conversion circuits are shown, it is easy to imagine that the converter contains more phases, such as three, four or more independent conversion units (see reference). Figures 4-6 All these variations fall within the scope of protection of this invention. Depending on the number of external power sources connected to the converter, the resonant converter includes multiple input ports, multiple conversion circuits, and (one) output port. Each conversion circuit is connected to a corresponding set of DC power sources among multiple sets of DC power sources via a corresponding input port among the multiple input ports, and is connected to an external load via the output port.

[0054] Each conversion circuit consists of an inverter bridge, a resonant circuit, a transformer, and a rectifier bridge. Each inverter bridge is connected to a corresponding input port, which converts the DC input signal received from that input port into a high-frequency AC signal. In particular, the inverter bridge may include a high-side input terminal connected to the positive terminal of a corresponding set of DC power supplies and a low-side input terminal connected to the negative terminal of the corresponding set of DC power supplies.

[0055] The high-frequency AC signal output from the inverter bridge is further provided to the resonant circuit. The resonant circuit (which may be an LLC resonator) generates a corresponding resonant signal based on the high-frequency AC signal received from the inverter bridge. The transformer further performs isolation transformation on the resonant signal output from the resonant circuit to change the voltage level of the resonant signal and output a modified transformed signal. This transformed signal is finally provided to the rectifier bridge, where it is converted back into a DC output signal. This DC output signal can be provided to the output port of the resonant converter to power the target load.

[0056] To simplify the description, Figure 4-6 The secondary circuit topology of the resonant converter is omitted here. In fact, the secondary circuit topology of the resonant converter can be any high-frequency rectification topology, as long as it can work normally in a conventional multiphase resonant converter topology, it can still work normally in this topology.

[0057] The following reference Figure 4 , Figure 5 , Figure 6 Several possible arrangements of the capacitor network in the resonant converter according to the present invention will be described.

[0058] exist Figure 4 In the arrangement, the capacitor network includes a first common contact and multiple capacitors CB1, CB2, CB3...CBN. Each capacitor is connected between the low-side input (or high-side input) of a corresponding inverter bridge in multiple conversion circuits and the first common contact.

[0059] exist Figure 5 In the arrangement, the capacitor network includes a second common contact, multiple first capacitors CB11, CB21, CB31...CBN1, and multiple second capacitors CB12, CB22, CB32...CBN2. Each first capacitor is connected between the high-side input of a corresponding inverter bridge in the multiple conversion circuits and the common contact, and each second capacitor is connected between the low-side input of a corresponding inverter bridge in the multiple conversion circuits connected to the common contact.

[0060] exist Figure 6In the arrangement, the capacitor network includes multiple third capacitors CB13, CB23, CB33...CBN3. Each third capacitor is connected between the low-side input or high-side input of a corresponding inverter bridge in multiple conversion circuits and the high-side input (or low-side input) of another inverter bridge in multiple conversion circuits.

[0061] By using the equivalent circuit, it can be known that... Figures 4-6 The specific topology of each capacitor network shown only affects the capacitance value and current waveform within the capacitor network, and has no impact on the overall normal operation of this multi-port resonant converter topology; therefore, they are equivalent.

[0062] Figure 7 A circuit diagram of a power supply assembly integrating the resonant converter according to the present invention is shown. Figure 7 As shown, the two battery packs BAT1 and BAT2 can each output a DC signal with a predetermined voltage value. They can be connected in series and in parallel by switching elements S1, S2 and S3 respectively. In order to accommodate this switching of the battery packs, an additional capacitor C12 can be connected in series between the two inverter bridges.

[0063] According to the multi-port resonant converter topology of the present invention, the voltage between each input port can float freely, making it suitable for applications where the voltage between each phase input power supply needs to float independently. Furthermore, this resonant inverter has a simple structure, few components, is easy to control, and has a wide voltage range gain and high conversion efficiency, making it particularly suitable for series-parallel switching schemes of multiple high-voltage batteries (or isolated power supplies) in electric vehicles. In addition, this resonant converter can reduce electromagnetic interference and improve the electromagnetic compatibility of the system, thereby significantly improving the overall performance and user experience of electric vehicles. This topology not only improves the flexibility and reliability of power conversion but also significantly enhances the efficiency and stability of the system.

[0064] Those skilled in the art will understand that the steps of the method according to the present invention are not limited to being performed in the order listed above. Furthermore, in this invention, terms such as "comprising" and "including" indicate that, in addition to the steps directly and explicitly stated in the specification and claims, the technical solution of this application does not exclude the presence of other steps not directly or explicitly stated.

[0065] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any modifications and alterations made by those skilled in the art without departing from the spirit and scope of the invention should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A resonant converter, the resonant converter comprising a plurality of input ports, a plurality of conversion circuits, and an output port, each conversion circuit being connected to a corresponding group of DC power supplies from a plurality of DC power supplies via a corresponding input port of the plurality of input ports, and connected to an external load via the output port, characterized in that, Each conversion circuit includes: An inverter bridge is connected to a corresponding input port among the plurality of input ports and is configured to convert a DC input signal received from the corresponding input port into a high-frequency AC signal. A resonant circuit configured to generate a corresponding resonant signal based on a high-frequency AC signal received from the inverter bridge; A transformer configured to perform an isolation transformation operation on a resonant signal output from the resonant circuit to change the voltage level of the resonant signal and output a modified transformed signal; and A rectifier bridge is configured to convert the transformer signal provided by the transformer back into a DC output signal and provide the DC output signal to the output port of the resonant converter. The resonant converter further includes a capacitor network consisting of at least one capacitor, which is disposed at any position in the primary loop of the conversion circuit.

2. The resonant converter according to claim 1, characterized in that, The inverter bridge includes a high-side input terminal connected to the positive terminal of a corresponding set of DC power supplies in the plurality of DC power supplies, and a low-side input terminal connected to the negative terminal of the corresponding set of DC power supplies.

3. The resonant converter according to claim 2, characterized in that, The at least one capacitor is disposed between the high-side input or low-side input of one inverter bridge in the plurality of conversion circuits and the high-side input or low-side input of another inverter bridge in the plurality of conversion circuits.

4. The resonant converter according to claim 2, characterized in that, The at least one capacitor is disposed between the output terminal of one resonant circuit in the plurality of conversion circuits and the output terminal of another resonant circuit in the plurality of conversion circuits.

5. The resonant converter according to claim 2, characterized in that, The capacitor network includes: First public contact point; and Multiple capacitors (CB1, CB2, CB3...CBN), each capacitor is connected between the low-side input or high-side input of a corresponding inverter bridge in the multiple conversion circuits and the first common contact.

6. The resonant converter according to claim 2, characterized in that, The capacitor network includes: Second public contact point; Multiple first capacitors (CB11, CB21, CB31...CBN1), each first capacitor connected between the high-side input of a corresponding inverter bridge in the multiple conversion circuits and the common contact; and Multiple second capacitors (CB12, CB22, CB32...CBN2), each second capacitor being connected between the low-side input terminals of a corresponding inverter bridge in the multiple conversion circuits at the common contact.

7. The resonant converter according to claim 2, characterized in that, The capacitor network includes multiple third capacitors (CB13, CB23, CB33...CBN3), each third capacitor being connected between the low-side or high-side input of a corresponding inverter bridge in the multiple conversion circuits and the high-side or low-side input of another inverter bridge in the multiple conversion circuits.

8. The resonant converter according to any one of claims 1 to 7, characterized in that, The resonant circuit includes an LLC resonator.

9. The resonant converter according to claim 8, characterized in that, The capacitance value of at least one capacitor in the capacitor network is set to be larger than the capacitance value of the capacitor in the LLC resonator.

10. A power supply assembly, characterized in that, The power supply assembly includes: Multiple DC power supplies, each configured to output a DC signal with a predetermined voltage value; and The resonant converter according to any one of claims 1 to 8.

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