Control method, system and control device of bidirectional resonant converter, storage medium and vehicle-mounted charger
By dynamically switching the operating mode of the bidirectional resonant converter in the on-board charger and adjusting the switching frequency to match the filter design, the problem of excessive EMI emissions in the low-voltage, low-power inverter mode of the CLLC full-bridge topology was solved, and the EMI performance was optimized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-27
AI Technical Summary
In low-voltage countries, on-board chargers using the CLLC full-bridge topology architecture in low-power inverter mode suffer from a mismatch between the switching frequency and filter design, leading to excessive electromagnetic interference (EMI) emissions.
Without changing the hardware design, the bidirectional resonant converter can be dynamically controlled to switch between half-bridge and full-bridge modes based on the charging power and charging current of the charging pile, and the switching frequency can be adjusted to match the filter design.
EMI performance has been optimized, making the CLLC full-bridge topology suitable for global power grids and avoiding the problem of excessive EMI emissions.
Smart Images
Figure CN121749768A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power supply technology, and in particular to a control method, system, control device, storage medium, and on-board charger for a bidirectional resonant converter. Background Technology
[0002] In the field of on-board chargers (OBCs), a CLLC full-bridge topology is typically used to achieve DC / DC conversion for forward charging and reverse inversion. The design of its circuit parameters and the full-bridge control algorithm are usually aimed at achieving optimal efficiency at full power. However, if this architecture is used in low-voltage countries (e.g., AC 110V / 120V) and in low-power inversion mode, the fixed circuit parameters prevent the full-bridge CLLC circuit from operating at a switching frequency close to other operating conditions by adjusting the bus voltage. This leads to a mismatch between the switching frequency and the filter design, resulting in excessive electromagnetic interference (EMI) emissions. Summary of the Invention
[0003] The main objective of this application is to provide a control method for a resonant converter, which aims to optimize the EMI performance of the CLLC full-bridge topology in low-voltage countries when operating in low-power inverter mode without changing the hardware design, so that the CLLC full-bridge topology can be applied to the global power grid.
[0004] To achieve the above objectives, this application provides a control method for a bidirectional resonant converter, characterized by comprising: When a communication connection is established with the charging pile, the charging power / charging current and the set switching frequency of the bidirectional resonant converter are obtained. If the set switching frequency is greater than a preset frequency threshold, and the charging power is less than or equal to a preset power threshold / the charging current is less than or equal to a preset current threshold, then the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter; and / or, If the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / the charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
[0005] Optionally, the bidirectional resonant converter includes a primary-side DC / AC conversion circuit, a CLLC resonant cavity, and a secondary-side AC / DC conversion circuit connected in series; the primary-side DC / AC circuit includes a first bridge arm unit and a second bridge arm unit connected in parallel; the first bridge arm unit includes a first switch and a second switch connected in series, and the second bridge arm unit includes a third switch and a fourth switch connected in series. The step of controlling the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter includes: The operating mode of the primary-side DC / AC conversion circuit is switched to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter; And / or, The control of switching the bidirectional resonant converter to full-bridge mode includes: controlling the operating mode of the primary-side DC / AC conversion circuit to switch to full-bridge mode.
[0006] Optionally, the control of the primary-side DC / AC conversion circuit to switch its operating mode to half-bridge mode specifically involves: The first switch is controlled to remain off, the second switch is controlled to remain on, and the third and fourth switches are controlled to alternately turn on; or... The first switch is kept on, the second switch is kept off, and the third and fourth switches are alternately turned on; or... The third switch is kept off, the fourth switch is kept on, and the first and second switches are alternately turned on; or... The third switch is kept on, the fourth switch is kept off, and the first and second switches are alternately turned on.
[0007] Furthermore, to achieve the above objectives, this application also provides a control system for a bidirectional resonant converter, comprising: The charging parameter acquisition unit is used to acquire the charging power / charging current and the set switching frequency of the bidirectional resonant converter when a communication connection is established with the charging pile. Control unit, used for: If the set switching frequency is greater than a preset frequency threshold, and the charging power is less than or equal to a preset power threshold / the charging current is less than or equal to a preset current threshold, then the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter; and / or, If the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / the charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
[0008] Optionally, the bidirectional resonant converter includes a primary-side DC / AC conversion circuit, a CLLC resonant cavity, and a secondary-side AC / DC conversion circuit connected in series; the primary-side DC / AC circuit includes a first bridge arm unit and a second bridge arm unit connected in parallel; the first bridge arm unit includes a first switch and a second switch connected in series, and the second bridge arm unit includes a third switch and a fourth switch connected in series. The control unit controls the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter, including: The control unit controls the primary-side DC / AC conversion circuit to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. And / or, The control unit controls the bidirectional resonant converter to switch to full-bridge mode, including: the control unit controls the primary-side DC / AC conversion circuit to switch its operating mode to full-bridge mode.
[0009] Optionally, the control unit controls the primary-side DC / AC conversion circuit to switch its operating mode to half-bridge mode, specifically: The first switch is controlled to remain off, the second switch is controlled to remain on, and the third and fourth switches are controlled to alternately turn on; or... The first switch is kept on, the second switch is kept off, and the third and fourth switches are alternately turned on; or... The third switch is kept off, the fourth switch is kept on, and the first and second switches are alternately turned on; or... The third switch is kept on, the fourth switch is kept off, and the first and second switches are alternately turned on.
[0010] In addition, to achieve the above objectives, this application also provides a control device, the control device comprising: a memory, a processor, and a control program for a bidirectional resonant converter stored in the memory and executable on the processor, the control program for the bidirectional resonant converter being configured to implement the control method for the bidirectional resonant converter as described above.
[0011] In addition, to achieve the above objectives, this application also provides a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the control method for the bidirectional resonant converter as described above.
[0012] In addition, to achieve the above objectives, this application also provides an on-board charger, which includes the control device as described above.
[0013] This application employs a control method for a bidirectional resonant converter. The method includes: when establishing a communication connection with a charging pile, acquiring the charging power / charging current and the set switching frequency of the bidirectional resonant converter; if the set switching frequency is greater than a preset frequency threshold, and the charging power is less than or equal to a preset power threshold / the charging current is less than or equal to a preset current threshold, then controlling the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. Thus, without changing the hardware design, the problem of excessive EMI emissions caused by the actual switching frequency of the bidirectional resonant converter deviating from the suppression band of the filter is avoided. On the other hand, if the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / the charging current is greater than the preset current threshold, then controlling the bidirectional resonant converter to switch to full-bridge mode. Thus, since the actual switching frequency of the bidirectional resonant converter operating under this condition is relatively low, the problem of excessive EMI emissions will not occur.
[0014] In summary, the solution provided in this application can control the bidirectional resonant converter to enter either half-bridge or full-bridge mode without changing the hardware design, based on the charging power / charging current of the charging pile and the set switching frequency of the bidirectional resonant converter. It takes into account both high and low voltage conditions, optimizes the EMI performance of the bidirectional resonant converter when operating in low-power inverter mode, and makes the bidirectional resonant converter applicable to the global power grid. Attached Figure Description
[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A flowchart illustrating the first embodiment of the control method for the bidirectional resonant converter provided in this application; Figure 2 A flowchart illustrating a second embodiment of the control method for a bidirectional resonant converter provided in this application; Figure 3A flowchart illustrating the third embodiment of the control method for the bidirectional resonant converter provided in this application; Figure 4 A schematic diagram of the structure of an embodiment of the control system of the bidirectional resonant converter provided in this application; Figure 5 The circuit architecture schematic diagram of the bidirectional resonant converter provided in this application; Figure 6 The schematic diagram of the first mode of the bidirectional resonant converter provided in this application in half-bridge mode; Figure 7 The schematic diagram of the second mode of the bidirectional resonant converter provided in this application, in half-bridge mode; Figure 8 The schematic diagram of the third mode of the bidirectional resonant converter provided in this application in half-bridge mode; Figure 9 The schematic diagram of the fourth mode of the bidirectional resonant converter provided in this application in half-bridge mode.
[0018] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Well-known modules, units, and their connections, links, communications, or operations are not shown or described in detail. Furthermore, the described features, architectures, or functions can be combined in any way in one or more embodiments. Those skilled in the art should understand that the various embodiments described below are only for illustration and not for limiting the scope of protection of this application. It is also readily understood that the modules or units or processing methods in the various embodiments described herein and shown in the accompanying drawings can be combined and designed in various different configurations. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] The definitions of various terms or methods used in the following embodiments are, except where logically impossible, generally defined as broad concepts that can be implemented based on the content disclosed in the embodiments. Under this understanding, all specific subordinate limitations of the terms or methods should be considered as part of the invention of this application, and should not be narrowly interpreted or biased simply because the specification does not disclose such a specific limitation. Similarly, provided that it is logically feasible, the order of the steps in the method is flexible and varied, and all specific subordinate limitations in the broad concepts of various terms or methods fall within the scope of protection of this application.
[0021] In this embodiment, for ease of description, the following description will focus on the control device as the executing entity.
[0022] Therefore, this application proposes a control method for a resonant converter; it is understood that the on-board charger is equipped with a control device for storing and executing the following method. The control device can be implemented using a main controller, such as an MCU (Micro Controller Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or a SOC (System On Chip).
[0023] In the field of on-board chargers (OBCs), a CLLC full-bridge topology is typically used to achieve DC / DC conversion for forward charging and reverse inversion. The design of its circuit parameters and the full-bridge control algorithm are usually aimed at achieving optimal efficiency at full power. However, if this architecture is used in low-voltage countries (e.g., AC 110V / 120V) and in low-power inversion mode, the fixed circuit parameters prevent the full-bridge CLLC circuit from operating at a switching frequency close to other operating conditions by adjusting the bus voltage. This leads to a mismatch between the switching frequency and the filter design, resulting in excessive electromagnetic interference (EMI) emissions.
[0024] Based on the above, referring to Figure 1 In the first embodiment of this application, the control method of the bidirectional resonant converter includes steps S10 to S21: Step S10: When a communication connection is established with the charging pile, the charging power / charging current and the set switching frequency of the bidirectional resonant converter are obtained.
[0025] In this embodiment, the charging power / charging current is the charging power / charging current of the charging pile, and the set switching frequency of the bidirectional resonant converter is a critical value set based on the topology of the bidirectional resonant converter, such as 100kHz according to the inherent frequency characteristics of the internal resonant cavity.
[0026] Step S21: If the set switching frequency is greater than the preset frequency threshold, and the charging power is less than or equal to the preset power threshold / the charging current is less than or equal to the preset current threshold, then control the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter.
[0027] In the context of charging power / charging current, the " / " sign means "or", indicating that either one is acceptable. Similarly, the " / " sign in "charging power less than or equal to preset power threshold / charging current less than or equal to preset current threshold" also means "or".
[0028] In this embodiment, the switching frequency of the bidirectional resonant converter, i.e. the actual switching frequency, is the switching frequency of all the switching transistors in the entire bidirectional resonant converter.
[0029] It should be noted that if the charging power obtained by the control device is less than or equal to the preset power threshold / the charging current is less than or equal to the preset current threshold, the bidirectional resonant converter operates in low-power inverter mode. Since the circuit parameters are fixed, if the actual switching frequency of the bidirectional resonant converter is too high, a design mismatch with the filter can easily occur, leading to excessive EMI emissions. In this embodiment, when the set switching frequency is greater than the preset frequency threshold, the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the actual switching frequency of the bidirectional resonant converter. Thus, without changing the hardware design, the problem of excessive EMI emissions caused by the actual switching frequency of the bidirectional resonant converter deviating from the suppression band of the filter is avoided, optimizing the EMI performance of the bidirectional resonant converter and making the CLLC full-bridge topology bidirectional resonant converter suitable for global power grids.
[0030] Based on the above, referring to Figure 2 In the second embodiment of this application, the control method of the bidirectional resonant converter includes steps S10 to S22: Step S10: When a communication connection is established with the charging pile, the charging power / charging current and the set switching frequency of the bidirectional resonant converter are obtained.
[0031] In this embodiment, the charging power / charging current is the charging power / charging current of the charging pile, and the set switching frequency of the bidirectional resonant converter is a critical value set based on the topology of the bidirectional resonant converter, such as 100kHz according to the inherent frequency characteristics of the internal resonant cavity.
[0032] Step S22: If the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / charging current is greater than the preset current threshold, then control the bidirectional resonant converter to switch to full-bridge mode.
[0033] In this embodiment, the switching frequency of the bidirectional resonant converter, i.e. the actual switching frequency, is the switching frequency of all the switching transistors in the entire bidirectional resonant converter.
[0034] It should be noted that if the charging power exceeds a preset power threshold / charging current exceeds a preset current threshold, the bidirectional resonant converter is not operating in low-power inverter mode. In this case, the bidirectional resonant converter is switched to full-bridge mode to increase the circuit gain and provide sufficient output power / current. Alternatively, if the switching frequency is set to be less than or equal to a preset frequency threshold, the actual switching frequency of the bidirectional resonant converter will not be too high even in full-bridge mode. In this case, the bidirectional resonant converter is switched to full-bridge mode to increase the circuit gain and provide sufficient output power / current. Thus, without changing the hardware design, the bidirectional resonant converter is switched to full-bridge mode only when the switching frequency is set to be less than or equal to a preset frequency threshold, or when the charging power exceeds a preset power threshold / charging current exceeds a preset current threshold. Since the actual switching frequency of the bidirectional resonant converter operating under these conditions is relatively low, it can still meet the output requirements, and there will be no problem of excessive EMI emissions. This optimizes the EMI performance of the bidirectional resonant converter, making the CLLC full-bridge topology bidirectional resonant converter suitable for global power grids.
[0035] Based on the above, referring to Figure 3 In the third embodiment of this application, the control method of the bidirectional resonant converter includes steps S10 to S23: Step S10: When a communication connection is established with the charging pile, the charging power / charging current and the set switching frequency of the bidirectional resonant converter are obtained.
[0036] In this embodiment, the charging power / charging current is the charging power / charging current of the charging pile, and the set switching frequency of the bidirectional resonant converter is a critical value set based on the topology of the bidirectional resonant converter, such as 100kHz according to the inherent frequency characteristics of the internal resonant cavity.
[0037] Step S23: If the set switching frequency is greater than the preset frequency threshold, and the charging power is less than or equal to the preset power threshold / the charging current is less than or equal to the preset current threshold, then control the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. If the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / the charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
[0038] In this embodiment, the switching frequency of the bidirectional resonant converter, i.e. the actual switching frequency, is the switching frequency of all the switching transistors in the entire bidirectional resonant converter.
[0039] It should be noted that if the charging power obtained by the control device is less than or equal to the preset power threshold / the charging current is less than or equal to the preset current threshold, the bidirectional resonant converter operates in low-power inverter mode. Since the circuit parameters are fixed, if the actual switching frequency of the bidirectional resonant converter is too high, a design mismatch with the filter can easily occur, leading to excessive EMI emissions. In this embodiment, when the set switching frequency is greater than the preset frequency threshold, the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the actual switching frequency of the bidirectional resonant converter. Thus, without changing the hardware design, the problem of excessive EMI emissions caused by the actual switching frequency of the bidirectional resonant converter deviating from the suppression band of the filter is avoided, optimizing the EMI performance of the bidirectional resonant converter and making the CLLC full-bridge topology bidirectional resonant converter suitable for global power grids.
[0040] It should be noted that if the charging power exceeds a preset power threshold / charging current exceeds a preset current threshold, the bidirectional resonant converter is not operating in low-power inverter mode. In this case, the bidirectional resonant converter is switched to full-bridge mode to increase the circuit gain and provide sufficient output power / current. Alternatively, if the switching frequency is set to be less than or equal to a preset frequency threshold, the actual switching frequency of the bidirectional resonant converter will not be excessive even in full-bridge mode. In this case, the bidirectional resonant converter is switched to full-bridge mode to increase the circuit gain and provide sufficient output power / current. Thus, without changing the hardware design, the bidirectional resonant converter is switched to full-bridge mode only when the switching frequency is less than or equal to a preset frequency threshold, or when the charging power exceeds a preset power threshold / charging current exceeds a preset current threshold. Because the actual switching frequency of the bidirectional resonant converter operating under these conditions is reduced, EMI emission exceeding the limit will not occur. This optimizes the EMI performance of the bidirectional resonant converter, making the CLLC full-bridge topology bidirectional resonant converter suitable for global power grids.
[0041] Thus, without changing the hardware design, this embodiment can dynamically control the bidirectional resonant converter to switch to half-bridge mode or full-bridge mode based on the charging power / charging current of the charging pile and the set switching frequency of the bidirectional resonant converter. This takes into account both high and low voltage conditions, optimizes the EMI performance of the bidirectional resonant converter when operating in low-power inverter mode, and makes the bidirectional resonant converter applicable to the global power grid.
[0042] Optionally, the fourth embodiment of this application provides a control method for a bidirectional resonant converter. Based on the first to third embodiments described above, the bidirectional resonant converter includes a primary-side DC / AC conversion circuit, a CLLC resonant cavity, and a secondary-side AC / DC conversion circuit connected in series. The primary-side DC / AC circuit includes a first bridge arm unit and a second bridge arm unit connected in parallel. The first bridge arm unit includes a first switch Q1 and a second switch Q2 connected in series, and the second bridge arm unit includes a third switch Q3 and a fourth switch Q4 connected in series. The control of switching the bidirectional resonant converter to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter includes: The operating mode of the primary-side DC / AC conversion circuit is switched to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. And / or, The control of switching the bidirectional resonant converter to full-bridge mode includes: The operating mode of the primary-side DC / AC conversion circuit is switched to full-bridge mode.
[0043] It should be noted that the primary-side DC / AC conversion circuit is a DC-AC conversion circuit used to convert the input DC voltage (such as DC bus voltage) into a high-frequency AC voltage; the CLLC resonant cavity includes a transformer and capacitors and inductors connected to the primary and secondary sides of the transformer respectively, which can realize efficient and compact isolated power transmission; the secondary-side AC / DC conversion circuit is an AC-DC conversion circuit used to rectify the high-frequency AC voltage output from the CLLC resonant cavity into a stable DC voltage.
[0044] It should be noted that, referring to Figure 5 According to such Figure 5 The circuit design of the bidirectional resonant converter shown includes: Formula 1
[0045] Formula 2
[0046] As can be seen from Formula 1, for a bidirectional resonant converter, the resonant inductance... and resonant capacitor Once determined, the circuit's switching frequency is set. constant.
[0047] As can be seen from Formula 2, after transformer T1 is fixed, its primary and secondary turns ratio : Unchanged; Input voltage and output voltage Once the requirements are determined, the circuit gain and Inversely proportional, for a full-bridge circuit =1, half-bridge circuit =0.5, and This is related to the switching frequency. Therefore, by changing the topology of the primary-side DC / AC converter circuit (half-bridge / full-bridge), the circuit gain can be effectively changed. This leads to changes and gains. The corresponding switching frequency. Thus, without changing the hardware design, this embodiment can adjust the switching frequency by controlling the operating mode of the primary-side DC / AC conversion circuit to switch between half-bridge and full-bridge modes.
[0048] It should be noted that in full-bridge mode, the first bridge arm (including switches Q1 and Q2) and the second bridge arm (including switches Q3 and Q4) of the primary-side DC / AC circuit are controlled by complementary drive signals from the control device. The control device can control the output of square wave voltages with a 180° phase difference between the two bridge arms, thereby forming an output voltage with an amplitude between the midpoints of the bridge arms. The AC excitation voltage. For example, four switches operate in a diagonal pair (Q1-Q4 and Q2-Q3) alternating conduction mode to achieve high-frequency inversion. Dead zones can also be provided between the switches in the bridge arm to avoid shoot-through.
[0049] Optionally, the fifth embodiment of this application provides a control method for a bidirectional resonant converter, based on the second embodiment, controlling the primary-side DC / AC conversion circuit to switch its operating mode to half-bridge mode, specifically: The first switch Q1 is kept off, the second switch Q2 is kept on, and the third switch Q3 and the fourth switch Q4 are alternately turned on; or... Control the first switch Q1 to remain on, control the second switch Q2 to remain off, and control the third switch Q3 and the fourth switch Q4 to alternately turn on; or... Control the third switch Q3 to remain off, control the fourth switch Q4 to remain on, and control the first switch Q1 and the second switch Q2 to alternately turn on; or... The third switch Q3 is kept on, the fourth switch Q4 is kept off, and the first switch Q1 and the second switch Q2 are alternately turned on.
[0050] It should be noted that the first to fourth switching transistors, Q4, can be implemented using MOSFETs or IGBTs. Reference Figure 6 In one embodiment, the control device controls the first switch Q1 to remain off, controls the second switch Q2 to remain on, and controls the third switch Q3 and the fourth switch Q4 to be turned on alternately. At this time, the midpoint of the first bridge arm unit is clamped to a fixed voltage, and the second bridge arm unit undertakes all high-frequency switching operations. At this time, under the same output power, due to the change in circuit gain, the second bridge arm unit can maintain low power transmission at a higher frequency, or avoid the frequency being too low under light load, thereby allowing the actual operating frequency of the circuit to fall within the matching range of the original filter design.
[0051] Reference Figure 7 In another embodiment, the control device controls the first switch Q1 to remain on, controls the second switch Q2 to remain off, and controls the third switch Q3 and the fourth switch Q4 to alternately turn on. At this time, the midpoint of the first bridge arm unit is clamped to another fixed voltage, and the second bridge arm unit undertakes all high-frequency switching operations. At this time, under the same output power, due to the change in circuit gain, the second bridge arm unit can maintain low power transmission at a higher frequency, or avoid the frequency being too low under light load, thereby allowing the actual operating frequency of the circuit to fall within the matching range of the original filter design.
[0052] Reference Figure 8 In another embodiment, the control device controls the third switch Q3 to remain off, controls the fourth switch Q4 to remain on, and controls the first switch Q1 and the second switch Q2 to alternately turn on. At this time, the midpoint of the bridge arm of the second bridge arm unit is clamped to a fixed voltage, and the first bridge arm unit undertakes all high-frequency switching operations. At this time, under the same output power, due to the change in circuit gain, the first bridge arm unit can maintain low power transmission at a higher frequency, or avoid the frequency being too low under light load, thereby allowing the actual operating frequency of the circuit to fall within the matching range of the original filter design.
[0053] Reference Figure 9 In another embodiment, the control device controls the third switch Q3 to remain on, controls the fourth switch Q4 to remain off, and controls the first switch Q1 and the second switch Q2 to alternately turn on. At this time, the midpoint of the bridge arm of the second bridge arm unit is clamped to another fixed voltage, and the first bridge arm unit undertakes all high-frequency switching operations. At this time, under the same output power, due to the change in circuit gain, the first bridge arm unit can maintain low power transmission at a higher frequency, or avoid the frequency being too low under light load, thereby allowing the actual operating frequency of the circuit to fall within the matching range of the original filter design.
[0054] Thus, without changing the hardware design, this embodiment can dynamically control the first or second bridge arm unit of the primary DC / AC circuit to undertake all high-frequency switching operations based on the charging power / charging current of the charging pile and the set switching frequency of the bidirectional resonant converter, thereby reducing the gain of the circuit and achieving the purpose of reducing the overall switching frequency of the bidirectional resonant converter. This makes the bidirectional resonant converter of this embodiment applicable to the global power grid.
[0055] Reference Figure 4 This application also proposes a control system for a bidirectional resonant converter, comprising: The charging parameter acquisition unit is used to acquire the charging power / charging current and the set switching frequency of the bidirectional resonant converter when a communication connection is established with the charging pile. Control unit, used for: If the switching frequency is greater than a preset frequency threshold, and the charging power is less than or equal to a preset power threshold / the charging current is less than or equal to a preset current threshold, then the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter; and / or, If the switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
[0056] In this embodiment, the charging parameter acquisition unit can acquire the charging power / charging current parameters of the charging pile in various ways. For example, it can directly receive the charging power or charging current commands issued by the charging pile through a communication interface module connected to the charging pile (such as CAN, RS485, PLC, or power line carrier). Alternatively, it can collect and calculate the charging power or charging current output by the charging pile in real time through a built-in power detection module or current detection module (such as configuring a current sensor or voltage sensor). No limitation is imposed here.
[0057] It should be noted that the control system of the bidirectional resonant converter in this embodiment may include a charging parameter acquisition unit and a control unit, and may also include a bidirectional resonant converter controlled by the control unit; however, this is not a limitation.
[0058] In this embodiment, if the charging power obtained by the control unit is less than or equal to a preset power threshold / the charging current is less than or equal to a preset current threshold, the bidirectional resonant converter operates in low-power inverter mode. Since the circuit parameters are fixed, if the actual switching frequency of the bidirectional resonant converter is too high, a design mismatch with the filter can easily occur, leading to excessive EMI emissions. In this embodiment, when the set switching frequency is greater than a preset frequency threshold, the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the actual switching frequency of the bidirectional resonant converter. Thus, without changing the hardware design, the problem of excessive EMI emissions caused by the actual switching frequency of the bidirectional resonant converter deviating from the suppression band of the filter is avoided.
[0059] In this embodiment, if the charging power is greater than a preset power threshold / the charging current is greater than a preset current threshold, the bidirectional resonant converter is not operating in low-power inverter mode. In this case, the bidirectional resonant converter is controlled to switch to full-bridge mode to increase the circuit gain during operation and provide sufficient output power / output current. Alternatively, if the switching frequency is set to be less than or equal to a preset frequency threshold, the actual switching frequency of the bidirectional resonant converter will not be too high even if it is in full-bridge mode. In this case, the bidirectional resonant converter is controlled to switch to full-bridge mode to increase the circuit gain during operation and provide sufficient output power / output current.
[0060] Thus, without changing the hardware design, this embodiment can dynamically control the bidirectional resonant converter to switch to half-bridge mode or full-bridge mode based on the charging power / charging current of the charging pile and the set switching frequency of the bidirectional resonant converter. This takes into account both high and low voltage conditions, optimizes the EMI performance of the bidirectional resonant converter when operating in low-power inverter mode, and makes the bidirectional resonant converter applicable to the global power grid.
[0061] In one embodiment, the bidirectional resonant converter includes a primary-side DC / AC conversion circuit, a CLLC resonant cavity, and a secondary-side AC / DC conversion circuit connected in series. The primary-side DC / AC circuit includes a first bridge arm unit and a second bridge arm unit connected in parallel. The first bridge arm unit includes a first switch Q1 and a second switch Q2 connected in series, and the second bridge arm unit includes a third switch Q3 and a fourth switch Q4 connected in series. The control unit controls the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter, including: The control unit controls the primary-side DC / AC conversion circuit to switch to half-bridge mode in order to reduce the switching frequency of the bidirectional resonant converter. And / or, The control unit controls the bidirectional resonant converter to switch to full-bridge mode, including: the control unit controls the primary-side DC / AC conversion circuit to switch to full-bridge mode.
[0062] In yet another embodiment, the control unit controls the primary-side DC / AC conversion circuit to switch its operating mode to half-bridge mode, specifically as follows: The first switch Q1 is kept off, the second switch Q2 is kept on, and the third switch Q3 and the fourth switch Q4 are alternately turned on; or... Control the first switch Q1 to remain on, control the second switch Q2 to remain off, and control the third switch Q3 and the fourth switch Q4 to alternately turn on; or... Control the third switch Q3 to remain off, control the fourth switch Q4 to remain on, and control the first switch Q1 and the second switch Q2 to alternately turn on; or... The third switch Q3 is kept on, the fourth switch Q4 is kept off, and the first switch Q1 and the second switch Q2 are alternately turned on.
[0063] Thus, without altering the hardware design, this embodiment allows for frequency adjustment by switching the operating mode of the primary-side DC / AC conversion circuit between half-bridge and full-bridge modes. In half-bridge mode, by dynamically controlling either the first or second bridge arm unit of the primary-side DC / AC circuit to handle all high-frequency switching actions, the circuit gain is reduced, thereby lowering the overall switching frequency of the bidirectional resonant converter. This makes the bidirectional resonant converter of this embodiment suitable for global power grids.
[0064] This application also proposes a control device, comprising: a memory, a processor, and a control program for a bidirectional resonant converter stored in the memory and executable on the processor. The control program for the bidirectional resonant converter is configured to implement the control method for the bidirectional resonant converter described above. Since the embodiments of the control device in this application employ all the technical solutions of all embodiments of the control method for the bidirectional resonant converter described above, they possess at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.
[0065] This application also proposes an on-board charger, which includes the control device as described in the above embodiments. Since the embodiments of the on-board charger in this application employ all the technical solutions of all embodiments of the control method for the bidirectional resonant converter described above, they possess at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.
[0066] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the control method of the bidirectional resonant converter in the above embodiments.
[0067] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.
[0068] The aforementioned computer-readable storage medium may be included in the control device; or it may exist independently and not be assembled into the control device.
[0069] The aforementioned computer-readable storage medium carries one or more programs, which, when executed by a control device, cause the control device to: When a communication connection is established with the charging pile, the charging power / charging current and the set switching frequency of the bidirectional resonant converter are obtained. If the switching frequency is greater than a preset frequency threshold, and the charging power is less than or equal to a preset power threshold / the charging current is less than or equal to a preset current threshold, then the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter; and / or, If the switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
[0070] Computer program code for performing the operations of this application can be written in one or more programming languages or a combination thereof, including object-oriented programming languages such as Java, Smalltalk, and C++, and conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).
[0071] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.
[0072] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.
[0073] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the control method of the bidirectional resonant converter described above. This allows for optimization of the EMI performance of the CLLC full-bridge topology in low-voltage countries operating in low-power inverter mode without altering the hardware design, thus making the CLLC full-bridge topology applicable to global power grids. Compared to the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the control method of the bidirectional resonant converter provided in the above embodiments, and will not be elaborated upon here.
[0074] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.
[0075] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0076] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of this application.
[0077] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. A control method for a bidirectional resonant converter, characterized in that, include: When a communication connection is established with the charging pile, the charging power / charging current and the set switching frequency of the bidirectional resonant converter are obtained. If the set switching frequency is greater than the preset frequency threshold, and the charging power is less than or equal to the preset power threshold / the charging current is less than or equal to the preset current threshold, then the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. And / or, If the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / the charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
2. The control method for a bidirectional resonant converter as described in claim 1, characterized in that, The bidirectional resonant converter includes a primary-side DC / AC conversion circuit, a CLLC resonant cavity, and a secondary-side AC / DC conversion circuit connected in series. The primary-side DC / AC circuit includes a first bridge arm unit and a second bridge arm unit connected in parallel. The first bridge arm unit includes a first switch and a second switch connected in series, and the second bridge arm unit includes a third switch and a fourth switch connected in series. The step of controlling the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter includes: The operating mode of the primary-side DC / AC conversion circuit is switched to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter; And / or, The control of switching the bidirectional resonant converter to full-bridge mode includes: controlling the operating mode of the primary-side DC / AC conversion circuit to switch to full-bridge mode.
3. The control method for a bidirectional resonant converter as described in claim 2, characterized in that, The control of switching the operating mode of the primary-side DC / AC conversion circuit to half-bridge mode is specifically as follows: The first switch is controlled to remain off, the second switch is controlled to remain on, and the third and fourth switches are controlled to alternately turn on; or... The first switch is kept on, the second switch is kept off, and the third and fourth switches are alternately turned on; or... The third switch is kept off, the fourth switch is kept on, and the first and second switches are alternately turned on; or... The third switch is kept on, the fourth switch is kept off, and the first and second switches are alternately turned on.
4. A control system for a bidirectional resonant converter, characterized in that, include: The charging parameter acquisition unit is used to acquire the charging power / charging current and the set switching frequency of the bidirectional resonant converter when a communication connection is established with the charging pile. Control unit, used for: If the set switching frequency is greater than the preset frequency threshold, and the charging power is less than or equal to the preset power threshold / the charging current is less than or equal to the preset current threshold, then the bidirectional resonant converter is controlled to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. And / or, If the set switching frequency is less than or equal to the preset frequency threshold, or the charging power is greater than the preset power threshold / the charging current is greater than the preset current threshold, then the bidirectional resonant converter is controlled to switch to full-bridge mode.
5. The control system of the bidirectional resonant converter as described in claim 4, characterized in that, The bidirectional resonant converter includes a primary-side DC / AC conversion circuit, a CLLC resonant cavity, and a secondary-side AC / DC conversion circuit connected in series. The primary-side DC / AC circuit includes a first bridge arm unit and a second bridge arm unit connected in parallel. The first bridge arm unit includes a first switch and a second switch connected in series, and the second bridge arm unit includes a third switch and a fourth switch connected in series. The control unit controls the bidirectional resonant converter to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter, including: The control unit controls the primary-side DC / AC conversion circuit to switch to half-bridge mode to reduce the switching frequency of the bidirectional resonant converter. And / or, The control unit controls the bidirectional resonant converter to switch to full-bridge mode, including: the control unit controls the primary-side DC / AC conversion circuit to switch its operating mode to full-bridge mode.
6. The control system of the bidirectional resonant converter as described in claim 5, characterized in that, The control unit controls the primary-side DC / AC conversion circuit to switch its operating mode to half-bridge mode, specifically: The first switch is controlled to remain off, the second switch is controlled to remain on, and the third and fourth switches are controlled to alternately turn on; or... The first switch is kept on, the second switch is kept off, and the third and fourth switches are alternately turned on; or... The third switch is kept off, the fourth switch is kept on, and the first and second switches are alternately turned on; or... The third switch is kept on, the fourth switch is kept off, and the first and second switches are alternately turned on.
7. A control device, characterized in that, The control device includes: a memory, a processor, and a control program for a bidirectional resonant converter stored in the memory and executable on the processor, wherein the control program for the bidirectional resonant converter is configured to implement the control method for the bidirectional resonant converter as described in any one of claims 1 to 3.
8. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the control method for the bidirectional resonant converter as described in any one of claims 1 to 3.
9. An on-board charger, characterized in that, Includes the control device as described in claim 7.