High-voltage charger and control method thereof

Abstract

The invention relates to the technical field of rail transit, and discloses a high-voltage charger and a control method thereof.A three-phase input series full-bridge resonance circuit is arranged in the high-voltage charger, the phase difference of the three-phase input series full-bridge resonance circuit is 120 degrees, so that current ripples can be counteracted mutually, the ripple and noise level of a system is reduced, and the system reliability is improved. The quality of an output signal is improved, so that the capacity of an output capacitor is reduced, and the design cost of the power supply is greatly reduced; the three-phase input series full-bridge resonant circuit adopts a connection mode of input series connection and output parallel connection, so that the total input power can be dispersed to each resonant circuit, and each circuit is a part of the total power needing to be processed, so that elements with smaller sizes and lower rated values are allowed to be used, and the cost of the power supply is further reduced; and the synchronous rectification circuit is used for rectifying the signal, so that the conduction power loss is greatly reduced, and the conversion efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of rail transit technology, and in particular to a high-voltage charger and a control method thereof. Background Art

[0002] Rail transit, especially modern public transportation systems such as subways, EMUs and high-speed railways, is an important part of urbanization and intercity transportation. These systems require efficient and reliable power supply to ensure the operation of trains. In rail transit, high-voltage converters play a vital role. They are used to convert and regulate electricity to meet the needs of trains and related infrastructure. In order to reduce the switching loss of high-voltage converters and improve conversion efficiency and power density, soft switching technology has emerged. Compared with hard-switching converters, soft-switching converters have better efficiency and EMI performance. Among them, LLC resonant converters are widely used in power conversion applications due to their own soft switching characteristics, converting power of one voltage level into power of another voltage level.

[0003] Although the LLC resonant converter has soft switching, which can improve efficiency and EMI performance, the output current of the transformer is a sinusoidal current, and the current peak value output on the rectifier side is the maximum current value of the sinusoidal current. The output current ripple is large, which requires more capacitors with large capacity to be connected in parallel on the load side, increasing the system volume and power supply design cost, which is not conducive to the stable operation of the whole machine. In addition, the use of diodes to rectify the signal will cause power loss, greatly reducing the conversion efficiency. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a high-voltage charger and a control method thereof, which can effectively solve the problems of large output current ripple on the rectifier side of the LLC resonant converter and power loss caused by signal rectification using diodes in the existing solution.

[0005] In a first aspect, an embodiment of the present application provides a high-voltage charger, including: an input energy storage circuit, a three-phase input series full-bridge resonant circuit, a three-phase parallel synchronous rectification circuit, an output energy storage circuit and a controller;

[0006] The positive electrode of the input energy storage circuit is used to connect to the positive electrode of the power supply, the negative electrode of the input energy storage circuit is used to connect to the negative electrode of the power supply, the input end of the three-phase input series full-bridge resonant circuit is electrically connected to the input energy storage circuit, the output end of the three-phase input series full-bridge resonant circuit is electrically connected to the input end of the three-phase parallel synchronous rectification circuit, the output end of the three-phase parallel synchronous rectification circuit is connected to the output energy storage circuit, the first output end of the three-phase parallel synchronous rectification circuit is also used to connect to the positive electrode of the load, and the second output end of the three-phase parallel synchronous rectification circuit is also used to connect to the negative electrode of the load;

[0007] The controller is used to control the phase difference of each pulse signal of the three-phase input series full-bridge resonant circuit to be 120 degrees, and control the three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit according to the target gain of the three-phase input series full-bridge resonant circuit.

[0008] In some embodiments, the input energy storage circuit includes three energy storage units, and the three energy storage units are connected in series between the positive electrode of the power supply and the negative electrode of the power supply;

[0009] The three-phase input series full-bridge resonant circuit includes three full-bridge resonant units, the three-phase parallel synchronous rectification circuit includes three synchronous rectification units, each of the full-bridge resonant units includes a full-bridge switch group and a resonant cavity, the input end of each full-bridge switch group is correspondingly connected to one of the energy storage units, and the output end of each full-bridge switch group is respectively coupled to each of the synchronous rectification units through each resonant cavity.

[0010] In some embodiments, each of the synchronous rectification units includes: a first switch group and a second switch group, the first switch group includes a first switch tube and a second switch tube connected in series, the second switch group includes a third switch tube and a fourth switch tube connected in series, the series node of the first switch tube and the second switch tube is connected to the positive output terminal of the resonant cavity, the series node of the third switch tube and the fourth switch tube is connected to the negative output terminal of the resonant cavity, and the first switch group and the second switch group are connected in parallel with the output energy storage circuit.

[0011] In some embodiments, the high-voltage charger also includes: a pre-charging circuit, the input end of the pre-charging circuit is used to connect to the positive electrode of the power supply, the output end of the pre-charging circuit is connected to the positive electrode of the input energy storage circuit, and the pre-charging circuit is used to protect the power supply when it is connected.

[0012] In some embodiments, the high-voltage charger further includes: an anti-reverse circuit, wherein the positive terminal of the anti-reverse circuit is used to connect to the power supply, and the negative terminal of the anti-reverse circuit is connected to the input terminal of the pre-charging circuit.

[0013] In some embodiments, the high-voltage charger also includes: an input filter circuit and an output filter circuit, the input end of the input filter circuit is used to connect to the power supply, the output end of the input filter circuit is electrically connected to the input energy storage circuit, the input end of the output filter circuit is connected to the output end of the three-phase parallel synchronous rectification circuit, and the output end of the output filter circuit is connected to the positive terminal of the output energy storage circuit.

[0014] In some embodiments, the high-voltage charger also includes: a first isolation circuit and a second isolation circuit, the input end of the first isolation circuit is electrically connected to the controller, the output end of the first isolation circuit is electrically connected to the three-phase input series full-bridge resonant circuit, the input end of the second isolation circuit is electrically connected to the controller, and the output end of the second isolation circuit is electrically connected to the three-phase parallel synchronous rectification circuit.

[0015] In a second aspect, an embodiment of the present application provides a control method for a high-voltage charger, the control method being applied to at least one high-voltage charger described in the first aspect, the control method comprising:

[0016] Controlling the phase difference of each pulse signal of the three-phase input series full-bridge resonant circuit to be 120 degrees;

[0017] Acquiring the input voltage and output voltage of the high-voltage charger in real time;

[0018] Obtaining a target gain according to the input voltage and the output voltage;

[0019] The three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit is adjusted in real time according to the target gain.

[0020] In some embodiments, controlling the three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit according to the target gain includes:

[0021] Determining whether the target gain is greater than a first preset gain;

[0022] If the target gain is greater than the first preset gain, adjusting the phase of the pulse signal of the three-phase parallel synchronous rectification circuit;

[0023] If the target gain is not greater than the first preset gain, the phase or frequency of the pulse signal of the three-phase input series full-bridge resonant circuit is adjusted.

[0024] In some embodiments, if the target gain is not greater than the first preset gain, adjusting the phase or frequency of the pulse signal of the three-phase input series full-bridge resonant circuit includes:

[0025] Determining whether the target gain is greater than a second preset gain;

[0026] If the target gain is greater than the second preset gain, adjusting the frequency of the pulse signal of the three-phase input series full-bridge resonant circuit;

[0027] If the target gain is not greater than the second preset gain, the phase of the pulse signal of the three-phase input series full-bridge resonant circuit is adjusted.

[0028] The embodiments of the present application have the following beneficial effects:

[0029] The high-voltage charger of the present application includes: an input energy storage circuit, a three-phase input series full-bridge resonant circuit, a three-phase parallel synchronous rectification circuit, an output energy storage circuit and a controller; the input end of the input energy storage circuit is connected to a power supply, and the energy of the power supply is stored to supply power to the three-phase input series full-bridge resonant circuit, the output end of the three-phase input series full-bridge resonant circuit is connected to the input end of the three-phase parallel synchronous rectification circuit, the output end of the three-phase parallel synchronous rectification circuit is connected to the input end of the output energy storage circuit, and the output end of the output energy storage circuit supplies power to the load. The present application sets a three-phase input series full-bridge resonant circuit in the high-voltage charger, and the three-phase input series full-bridge resonant circuit The phase difference of the circuit is 120 degrees, so that the current ripples can offset each other, reducing the ripple and noise level of the system, improving the quality of the output signal, thereby reducing the capacity of the output capacitor and greatly reducing the design cost of the power supply; and the three-phase input series full-bridge resonant circuit adopts the connection method of input series and output parallel connection, which can disperse the total input power to each resonant circuit, and each circuit only needs to process a part of the total power, thereby allowing the use of smaller size and lower rated components, further reducing the cost of the power supply; using a synchronous rectification circuit to rectify the signal, greatly reducing the conduction power loss and improving the conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A first structural schematic diagram of a high-voltage charger according to an embodiment of the present application is shown;

[0032] Figure 2 A second structural schematic diagram of a high-voltage charger according to an embodiment of the present application is shown;

[0033] Figure 3 A circuit diagram of a high-voltage charger according to an embodiment of the present application is shown;

[0034] Figure 4 A third structural schematic diagram of the high-voltage charger according to an embodiment of the present application is shown;

[0035] Figure 5 A first flow chart of a control method of a high-voltage charger according to an embodiment of the present application is shown;

[0036] Figure 6A second flow chart of the control method of the high-voltage charger according to an embodiment of the present application is shown;

[0037] Figure 7 A third flow chart of the control method of the high-voltage charger according to an embodiment of the present application is shown.

[0038] Description of main component symbols: 10: input energy storage circuit; 11: three-phase input series full-bridge resonant circuit; 12: three-phase parallel synchronous rectification circuit; 13: output energy storage circuit; 14: controller;

[0039] 15: power supply; 16: load; 17: pre-charging circuit; 18: anti-reverse circuit; 19: input filter circuit; 20: output filter circuit; 21: first isolation circuit; 22: second isolation circuit; 101: energy storage unit; 111: full-bridge resonant unit; 121: synchronous rectification unit. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0041] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0042] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0043] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0044] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0045] Taking into account the problems of large output current ripple on the rectifier side of the LLC resonant converter in the existing solution and power loss caused by signal rectification using diodes, the present application proposes a high-voltage charger and a control method thereof. The present application sets a three-phase full-bridge resonant circuit in the high-voltage charger. The phase difference of the three-phase full-bridge resonant circuit is 120 degrees, so that the current ripples can offset each other, reducing the ripple and noise level of the system, improving the quality of the output signal, thereby reducing the capacity of the output capacitor and greatly reducing the design cost of the power supply; and the three-phase input series full-bridge resonant circuit adopts an input series and output parallel connection method, which can disperse the total input power to each resonant circuit, and each circuit only needs to process a part of the total power, thereby allowing the use of smaller size and lower rated components, further reducing the cost of the power supply; using a synchronous rectification circuit to rectify the signal, greatly reducing the conduction power loss and improving the conversion efficiency.

[0046] The high-voltage charger is described below in conjunction with some specific embodiments.

[0047] In one embodiment, Figure 1 A schematic diagram of the structure of a high-voltage charger according to an embodiment of the present application is shown. The high-voltage charger comprises: an input energy storage circuit 10, a three-phase input series full-bridge resonant circuit 11, a three-phase parallel synchronous rectification circuit 12, an output energy storage circuit 13 and a controller 14.

[0048] The positive electrode of the input energy storage circuit 10 is used to connect to the positive electrode of the power supply 15, and the negative electrode of the input energy storage circuit 10 is used to connect to the negative electrode of the power supply 15. The input end of the three-phase input series full-bridge resonant circuit 11 is electrically connected to the input energy storage circuit 10. It can be understood that a plurality of energy storage capacitors can be provided in the input energy storage circuit 10 of this embodiment, and the input end of the three-phase input series full-bridge resonant circuit 11 can be connected in series using a plurality of energy storage capacitors.

[0049] The output end of the three-phase input series full-bridge resonant circuit 11 is electrically connected to the input end of the three-phase parallel synchronous rectifier circuit 12, the output end of the three-phase parallel synchronous rectifier circuit 12 is connected to the output energy storage circuit 13, the first output end of the three-phase parallel synchronous rectifier circuit 12 is also used to connect the positive electrode of the load 16, and the second output end of the three-phase parallel synchronous rectifier circuit 12 is also used to connect the negative electrode of the load 16. As an optional solution, each full-bridge resonant circuit in the three-phase input series full-bridge resonant circuit 11 is an LLC full-bridge resonant circuit, and each synchronous rectifier circuit in the three-phase parallel synchronous rectifier circuit 12 is a full-bridge rectifier circuit.

[0050] Preferably, the voltage at the input end of the high-voltage charger of this embodiment, that is, the voltage of the power source 15, ranges from 1000V to 2000V.

[0051] In this embodiment, the controller 14 is used to control the phase difference of each pulse signal of the three-phase input series full-bridge resonant circuit to be 120 degrees, and control the three-phase input series full-bridge resonant circuit 11 or the three-phase parallel synchronous rectifier circuit 12 according to the target gain of the three-phase input series full-bridge resonant circuit 11. Optionally, the controller 14 and the three-phase input series full-bridge resonant circuit 11 and the three-phase parallel synchronous rectifier circuit 12 can be provided with an isolation circuit, and the isolation circuit is used to achieve isolation between the primary circuit and the secondary circuit of the transformer in the three-phase input series full-bridge resonant circuit 11.

[0052] It can be understood that the controller 14 can control the pulse signal of the three-phase input series full-bridge resonant circuit 11 according to the target gain, and control the output voltage of the high-voltage charger by adjusting the frequency or phase of the pulse signal of the three-phase input series full-bridge resonant circuit 11. The controller 14 can also control the pulse signal of the three-phase parallel synchronous rectifier circuit 12 according to the target gain, and control the output voltage of the high-voltage charger by adjusting the frequency or phase of the pulse signal of the three-phase parallel synchronous rectifier circuit 12.

[0053] The high-voltage charger of this embodiment is provided with a three-phase input series full-bridge resonant circuit 11 and a three-phase full-bridge synchronous rectification circuit. The three-phase input series full-bridge resonant circuit 11 can reduce the ripple of the output voltage through the phase difference between each full-bridge resonant circuit, so that the capacity of the capacitor in the output energy storage circuit 13 is relatively small, which is beneficial to controlling the cost of the high-voltage charger. In addition, each synchronous rectification circuit in the three-phase synchronous rectification circuit performs rectification, and the on-resistance of the switch tube in the synchronous rectification circuit is much lower than the forward voltage of the diode, which can significantly reduce energy loss.

[0054] As an optional solution, Figure 2 FIG. 1 is another schematic diagram of the structure of a high-voltage charger. Figure 3 Shown Figure 2A circuit diagram of a high-voltage charger.

[0055] In one embodiment, if Figure 2 and Figure 3 As shown, based on the above embodiment, the input energy storage circuit 10 includes three energy storage units 101, and the three energy storage units 101 are sequentially connected in series between the positive electrode of the power supply 15 and the negative electrode of the power supply 15. A capacitor can be set in each energy storage unit 101, or multiple capacitors can be set in the energy storage unit 101. Preferably, the capacity of the three energy storage units 101 is the same, which can ensure the balanced distribution of the current of each phase in the three-phase circuit.

[0056] The high-voltage charger of this embodiment sets three energy storage units 101 in the input energy storage circuit 10, and uses three capacitors with the same capacity to realize the input series connection of the three-phase input series full-bridge resonant circuit 11, which can ensure that the circuit works in a three-phase balanced state and improve the efficiency, stability and reliability of the circuit.

[0057] In one embodiment, if Figure 2 As shown, the three-phase input series full-bridge resonant circuit 11 includes three full-bridge resonant units 111, and the three-phase parallel synchronous rectification circuit 12 includes three synchronous rectification units 121. Each full-bridge resonant unit 111 includes a full-bridge switch group and a resonant cavity. The input end of each full-bridge switch group is correspondingly connected to an energy storage unit 101, and the output end of each full-bridge switch group is respectively coupled to each synchronous rectification unit 121 through each resonant cavity.

[0058] Among them, each full-bridge resonant unit 111 includes four switching tubes constituting a double bridge arm, the double bridge arm of the full-bridge resonant unit 111 includes a first bridge arm and a second bridge arm, each synchronous rectification unit 121 includes four switching tubes constituting a double bridge arm, the double bridge arm of the synchronous rectification unit 121 includes a third bridge arm and a fourth bridge arm, and each resonant cavity includes a resonant inductor, a resonant capacitor and a transformer respectively, wherein one end of the primary winding of the transformer is connected to the middle node of the first bridge arm through the resonant inductor, and the other end of the primary winding is connected to the middle node of the second bridge arm through the resonant capacitor, one end of the secondary winding of the transformer is connected to the central node of the third bridge arm, and the other end of the secondary winding is connected to the middle node of the fourth bridge arm.

[0059] In one embodiment, if Figure 3 As shown, on the basis of the above embodiment, each synchronous rectification unit 121 includes: a first switch group and a second switch group, the first switch group includes a first switch tube and a second switch tube connected in series, the second switch group includes a third switch tube and a fourth switch tube connected in series, the series node of the first switch tube and the second switch tube is connected to the positive pole of the output end of the resonant cavity, the series node of the third switch tube and the fourth switch tube is connected to the negative pole of the output end of the resonant cavity, and the first switch group, the second switch group and the output energy storage circuit 13 are connected in parallel.

[0060] Preferably, the synchronous rectifier is provided with a low on-resistance under low voltage and high current conditions to reduce power loss during the rectification process.

[0061] The high-voltage charger of this embodiment sets the synchronous rectification circuit to a full-bridge synchronous rectification circuit. The full-bridge synchronous rectification circuit can meet the requirements of the system with high efficiency and ensure the stability of the circuit.

[0062] In one embodiment, if Figure 2 and Figure 3 As shown, based on the above embodiment, the high-voltage charger also includes: a pre-charging circuit 17, the input end of the pre-charging circuit 17 is used to connect to the positive electrode of the power supply 15, the output end of the pre-charging circuit 17 is connected to the positive electrode of the input energy storage circuit 10, and the pre-charging circuit 17 is used to protect the power supply 15 when it is connected.

[0063] Specifically, the pre-charging circuit 17 is provided with a main switch branch and an auxiliary switch branch, wherein the main switch branch is provided with a switch, and the auxiliary switch branch is provided with a switch and a resistor connected in series. It can be understood that the switch in the pre-charging circuit 17 of this embodiment is a relay. As other implementation methods, the switch in the pre-charging circuit 17 can be any type of electric switch, and the switch in the pre-charging circuit 17 can also be a manual switch.

[0064] The working process of the high-voltage charger of this embodiment is as follows: before the main switch branch is turned on, the relay in the auxiliary switch branch is controlled to be turned on, and the input energy storage circuit 10 is charged through the auxiliary switch branch until the capacitor voltage in the input energy storage circuit 10 is close to the voltage of the power supply 15, and the main switch branch is controlled to be turned on.

[0065] The high-voltage charger of this embodiment is provided with a pre-charging circuit 17 between the input energy storage circuit 10 and the power supply 15 to protect the power supply 15, so as to avoid directly turning on the main switch branch, causing the capacitor current in the input energy storage circuit 10 to increase instantly, thereby preventing the large current from impacting the power supply 15, protecting the circuit components, and ensuring a smooth transition between the power supply 15 and the capacitor.

[0066] In one embodiment, if Figure 2 and Figure 3 As shown, based on the above embodiment, the high-voltage charger also includes: an anti-reverse circuit 18, the positive terminal of the anti-reverse circuit 18 is used to connect to the power supply 15, and the negative terminal of the anti-reverse circuit 18 is connected to the input end of the pre-charging circuit 17.

[0067] Specifically, a single diode or multiple diodes may be provided in the anti-reverse circuit 18 to protect the power supply 15 , so that the current can only flow from the power supply 15 to the input energy storage circuit 10 .

[0068] The high-voltage charger of this embodiment is provided with an anti-reverse circuit 18 at the output end of the power source 15. The anti-reverse circuit 18 can protect the circuit and ensure the stability of the circuit.

[0069] In one embodiment, if Figure 2 and Figure 3 As shown, based on the above embodiment, the high-voltage charger also includes: an input filter circuit 19 and an output filter circuit 20, the input end of the input filter circuit 19 is used to connect to the power supply 15, the output end of the input filter circuit 19 is electrically connected to the input energy storage circuit 10, the input end of the output filter circuit 20 is connected to the output end of the three-phase parallel synchronous rectification circuit 12, and the output end of the output filter circuit 20 is connected to the positive terminal of the output energy storage circuit 13.

[0070] For example, a filter and / or a filter capacitor may be provided in the filter circuit to filter the signal in the circuit. For example, Figure 3 As shown, a filter is provided in the input filter circuit 19 for filtering, and a filter and a filter capacitor are provided in the output filter circuit 20 for filtering.

[0071] The high-voltage charger of this embodiment is provided with an input filter circuit 19 and an output filter circuit 20 at the output end of the power supply 15. The input filter circuit 19 can remove high-frequency noise in the output of the power supply 15, suppress electromagnetic interference, greatly improve the signal quality, and ensure the reliability of the circuit.

[0072] Figure 4 Another structural schematic diagram of a high-voltage charger of an embodiment of the present application is shown. Based on the above embodiment, the high-voltage charger further includes: a first isolation circuit 21 and a second isolation circuit 22, the input end of the first isolation circuit 21 is electrically connected to the controller 14, the output end of the first isolation circuit 21 is electrically connected to the three-phase input series full-bridge resonant circuit 11, the input end of the second isolation circuit 22 is electrically connected to the controller 14, and the output end of the second isolation circuit 22 is electrically connected to the three-phase parallel synchronous rectification circuit 12.

[0073] In order to synchronously control the three-phase input series full-bridge resonant circuit 11 and the three-phase parallel synchronous rectifier circuit 12, the same controller 14 is used to control the switch tubes in the three-phase input series full-bridge resonant circuit 11 and the three-phase parallel synchronous rectifier circuit 12, but the circuit on the primary side of the transformer and the circuit on the secondary side of the transformer in the three-phase input series full-bridge resonant circuit 11 need to be isolated. Based on this, in this embodiment, a first isolation circuit 21 is set between the controller 14 and the three-phase input series full-bridge resonant circuit 11, and a second isolation circuit 22 is set between the controller 14 and the three-phase parallel synchronous rectifier circuit 12. The first isolation circuit 21 and the second isolation circuit 22 are used to ensure that the three-phase input series full-bridge resonant circuit 11 and the three-phase parallel synchronous rectifier circuit 12 can be synchronously controlled while achieving isolation between the primary circuit and the secondary circuit.

[0074] It is understandable that the connection controller 14 is also provided with an isolation circuit on the circuit for current sampling and voltage sampling of the three-phase input series full-bridge resonant circuit 11 and the three-phase parallel synchronous rectification circuit 12, so as to further ensure the isolation between the primary circuit and the secondary circuit.

[0075] Preferably, a transformer is provided in the first isolation circuit 21 for isolation, and a transformer is provided in the second isolation circuit 22 for isolation.

[0076] In the high-voltage charger of this embodiment, an isolation circuit is set between the controller 14 and the three-phase input series full-bridge resonant circuit 11 and the three-phase parallel synchronous rectification circuit 12 for isolation. The isolation circuit can protect the controller 14 to ensure the safety of the system, and can also realize isolation between the primary circuit and the secondary circuit while synchronously controlling the system, thereby reducing interference between the circuits and ensuring the safety of the circuits.

[0077] The present application also provides a control method for a high-voltage charger. Figure 5 A flow chart of a control method of a high-voltage charger according to an embodiment of the present application is shown. The control method is applied to the high-voltage charger mentioned in any of the above embodiments. The control method is executed by a controller 14 in the high-voltage charger, and includes:

[0078] Step S101: Control the phase difference of each pulse signal of the three-phase input series full-bridge resonant circuit to be 120 degrees.

[0079] The pulse signal of the three-phase input series full-bridge resonant circuit is the pulse signal of the control switch tube of each series full-bridge resonant circuit, and the phase difference between the pulse signals of each series full-bridge resonant circuit is 120 degrees.

[0080] Step S102: Obtain the input voltage and output voltage of the high-voltage charger in real time.

[0081] The input voltage and output voltage of the high-voltage charger can be obtained through the voltage sampling circuit.

[0082] Step S103: obtaining a target gain according to the input voltage and the output voltage.

[0083] The target gain is the ratio of the output voltage to the input voltage. The target gain is calculated based on the preset output voltage.

[0084] Step S104: adjusting the three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit in real time according to the target gain.

[0085] The output voltage of the high-voltage charger can be controlled by adjusting the frequency or phase of the pulse signal of the three-phase input series full-bridge resonant circuit according to the target gain, or the pulse signal of the three-phase parallel synchronous rectifier circuit can be controlled according to the target gain, and the output voltage of the high-voltage charger can be controlled by adjusting the frequency or phase of the pulse signal of the three-phase parallel synchronous rectifier circuit.

[0086] The target gain can be divided into several stages, and the circuit can be controlled differently according to different stages. Furthermore, a hysteresis interval can be set between the stages of the target gain to avoid oscillation when the control scheme switches at the input voltage or the output voltage.

[0087] In this embodiment, the circuit is controlled differently according to different target gains, so that the high-voltage charger has a wider gain range and the ability to work under a wide range of input voltages, thereby ensuring that the high-voltage charger has wide gain and high efficiency.

[0088] In one embodiment, if Figure 6 As shown, a flow chart of a control method of a high-voltage charger according to an embodiment of the present application is provided. Based on the above embodiment, step S103 includes:

[0089] Step S201: determining whether the target gain is greater than a first preset gain.

[0090] For example, if the first preset gain is 1.4, when the target gain is greater than 1.4, the frequency modulation control will cause the frequency to be too low, but if the frequency is too low, low-frequency ripple will appear, and a larger filter capacitor needs to be set, but a larger capacity will result in a larger capacitor volume. Therefore, the target gain greater than 1.4 is set as a stage, and the secondary circuit is controlled by phase shifting.

[0091] Step S202: If the target gain is greater than the first preset gain, adjust the phase of the pulse signal of the three-phase parallel synchronous rectification circuit.

[0092] Specifically, the three-phase parallel synchronous rectification circuits are adjusted simultaneously, and the time for supplying power to the load is reduced by reducing the simultaneous conduction time of the middle pair of tubes in each synchronous rectification circuit. When the energy is constant, the power and time are inversely proportional. The power consumed by the load increases, and the voltage of the load increases.

[0093] Step S203: If the target gain is not greater than the first preset gain, adjust the phase or frequency of the pulse signal of the three-phase input series full-bridge resonant circuit.

[0094] For example, if the target gain is no more than 1.4, the output voltage of the high-voltage charger is controlled by adjusting the frequency or phase of the pulse signal of the three-phase input series full-bridge resonant circuit. Further, the target gain of no more than 1.4 can be divided into two stages, and the primary circuit is controlled differently according to different stages.

[0095] In this embodiment, when the target gain is greater than 1.4, the voltage of the load is increased by reducing the simultaneous conduction time of the middle pair of tubes in each synchronous rectifier circuit, avoiding the large size of the filter capacitor and making the high-voltage charger have a wider gain range.

[0096] In one embodiment, if Figure 7 As shown, based on the above embodiment, step S203 includes:

[0097] Step S301: determining whether the target gain is greater than a second preset gain.

[0098] Preferably, the second preset gain is 0.95, and between 0.95-1.4, the frequency modulation control is in the low frequency zone, and at this stage, only a slight adjustment needs to be made to the frequency of the pulse signal of the three-phase input series full-bridge resonant circuit to make a significant change in the target gain; when the target gain is less than 0.96, the frequency modulation control is in the high frequency zone, and at this stage, a great adjustment needs to be made to the frequency of the pulse signal of the three-phase input series full-bridge resonant circuit to change the target gain, therefore, the target gain is set to be less than 0.96 as a stage, and the output voltage is controlled by adjusting the phase of the pulse signal of the three-phase input series full-bridge resonant circuit.

[0099] Step S302: If the target gain is greater than the second preset gain, adjust the frequency of the pulse signal of the three-phase input series full-bridge resonant circuit.

[0100] Specifically, the three-phase input series full-bridge resonant circuit 11 is adjusted at the same time. If the output voltage is reduced, the frequency of the pulse signal of each full-bridge resonant circuit can be increased. If the output voltage is increased, the frequency of the pulse signal of each full-bridge resonant circuit can be reduced. When the pulse signal frequency is increased, the time for transmitting energy is reduced, the energy consumed by the load is reduced, and the voltage of the load will become lower.

[0101] Step S303 : If the target gain is not greater than the second preset gain, adjusting the phase of the pulse signal of the three-phase input series full-bridge resonant circuit 11 .

[0102] Specifically, the frequency of the pulse signal of each full-bridge resonant circuit is set to a fixed value, and at the same time, the duty cycle of one group of tubes is fixed, and the duty cycle of another group of tubes is reduced, that is, the conduction time of another group of tubes is reduced, so that the output voltage can be reduced.

[0103] In this embodiment, when the target gain is set between the first preset gain and the second preset gain, the output voltage is controlled by adjusting the frequency of the pulse signal of the full-bridge resonant circuit, giving full play to the advantages of soft switching and wide gain of the resonant state in the low-frequency region; and when the target gain is below the second preset gain, the output voltage is reduced by phase shifting, combining the characteristics of low loss of frequency modulation and wide gain of phase shifting, so that the high-voltage charger has wide gain and high efficiency.

[0104] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0105] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0106] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0107] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A high voltage charger, characterized in that: include: Input energy storage circuit, three-phase input series full-bridge resonant circuit, three-phase parallel synchronous rectification circuit, output energy storage circuit and controller; The positive electrode of the input energy storage circuit is used to connect to the positive electrode of the power supply, the negative electrode of the input energy storage circuit is used to connect to the negative electrode of the power supply, the input end of the three-phase input series full-bridge resonant circuit is electrically connected to the input energy storage circuit, the output end of the three-phase input series full-bridge resonant circuit is electrically connected to the input end of the three-phase parallel synchronous rectification circuit, the output end of the three-phase parallel synchronous rectification circuit is connected to the output energy storage circuit, the first output end of the three-phase parallel synchronous rectification circuit is also used to connect to the positive electrode of the load, and the second output end of the three-phase parallel synchronous rectification circuit is also used to connect to the negative electrode of the load; The controller is used to control the phase difference of each pulse signal of the three-phase input series full-bridge resonant circuit to be 120 degrees, and control the three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit according to the target gain of the three-phase input series full-bridge resonant circuit.

2. The high-voltage charger according to claim 1, characterized in that: The input energy storage circuit comprises three energy storage units, and the three energy storage units are connected in series between the positive electrode of the power supply and the negative electrode of the power supply; The three-phase input series full-bridge resonant circuit includes three full-bridge resonant units, the three-phase parallel synchronous rectification circuit includes three synchronous rectification units, each of the full-bridge resonant units includes a full-bridge switch group and a resonant cavity, the input end of each full-bridge switch group is correspondingly connected to one of the energy storage units, and the output end of each full-bridge switch group is respectively coupled to each of the synchronous rectification units through each resonant cavity.

3. The high-voltage charger according to claim 2, characterized in that: Each of the synchronous rectification units includes: a first switch group and a second switch group, the first switch group includes a first switch tube and a second switch tube connected in series, the second switch group includes a third switch tube and a fourth switch tube connected in series, the series node of the first switch tube and the second switch tube is connected to the positive output terminal of the resonant cavity, the series node of the third switch tube and the fourth switch tube is connected to the negative output terminal of the resonant cavity, and the first switch group and the second switch group are connected in parallel with the output energy storage circuit.

4. The high-voltage charger according to claim 1, characterized in that: The high-voltage charger also includes: a pre-charging circuit, the input end of the pre-charging circuit is used to connect to the positive electrode of the power supply, the output end of the pre-charging circuit is connected to the positive electrode of the input energy storage circuit, and the pre-charging circuit is used to protect the power supply when it is connected.

5. The high-voltage charger according to claim 4, characterized in that: The high-voltage charger further includes: an anti-reverse circuit, wherein a positive terminal of the anti-reverse circuit is used to connect to the power supply, and a negative terminal of the anti-reverse circuit is connected to an input terminal of the pre-charging circuit.

6. The high-voltage charger according to claim 1, characterized in that: The high-voltage charger also includes: an input filter circuit and an output filter circuit, the input end of the input filter circuit is used to connect to the power supply, the output end of the input filter circuit is electrically connected to the input energy storage circuit, the input end of the output filter circuit is connected to the output end of the three-phase parallel synchronous rectification circuit, and the output end of the output filter circuit is connected to the positive terminal of the output energy storage circuit.

7. The high-voltage charger according to claim 1, characterized in that: The high-voltage charger also includes: a first isolation circuit and a second isolation circuit, the input end of the first isolation circuit is electrically connected to the controller, the output end of the first isolation circuit is electrically connected to the three-phase input series full-bridge resonant circuit, the input end of the second isolation circuit is electrically connected to the controller, and the output end of the second isolation circuit is electrically connected to the three-phase parallel synchronous rectification circuit.

8. A control method for a high-voltage charger, characterized in that: The control method of the high-voltage charger is applied to the high-voltage charger according to any one of claims 1 to 7, and the control method includes: Controlling the phase difference of each pulse signal of the three-phase input series full-bridge resonant circuit to be 120 degrees; Acquiring the input voltage and output voltage of the high-voltage charger in real time; Obtaining a target gain according to the input voltage and the output voltage; The three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit is adjusted in real time according to the target gain.

9. The control method of the high-voltage charger according to claim 8, characterized in that: The controlling the three-phase input series full-bridge resonant circuit or the three-phase parallel synchronous rectification circuit according to the target gain includes: Determining whether the target gain is greater than a first preset gain; If the target gain is greater than the first preset gain, adjusting the phase of the pulse signal of the three-phase parallel synchronous rectification circuit; If the target gain is not greater than the first preset gain, the phase or frequency of the pulse signal of the three-phase input series full-bridge resonant circuit is adjusted.

10. The control method of the high-voltage charger according to claim 9, characterized in that: If the target gain is not greater than the first preset gain, adjusting the phase or frequency of the pulse signal of the three-phase input series full-bridge resonant circuit includes: Determining whether the target gain is greater than a second preset gain; If the target gain is greater than the second preset gain, adjusting the frequency of the pulse signal of the three-phase input series full-bridge resonant circuit; If the target gain is not greater than the second preset gain, the phase of the pulse signal of the three-phase input series full-bridge resonant circuit is adjusted.

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