Vehicle-mounted charger, charging control method and device thereof and vehicle

Abstract

The invention discloses a vehicle-mounted charger, a charging control method and device thereof and a vehicle, the vehicle-mounted charger comprises an LLC circuit, the LLC circuit is used for being electrically connected with a vehicle-mounted battery, and the LLC circuit is electrically connected with a first sampling circuit used for sampling the output current of the LLC circuit; the charging control method comprises the following steps: controlling the vehicle-mounted charger to charge the vehicle-mounted battery; when the first sampling circuit does not fail, the LLC circuit is controlled in a frequency modulation control mode; and / or, when the first sampling circuit fails, the LLC circuit is controlled in a fixed frequency control mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicles, and more particularly to an on-board charger and a charging control method and device thereof, and a vehicle. BACKGROUND

[0002] An on-board charger (OBC) includes a PFC circuit and an LLC circuit. The PFC circuit as a front stage mainly performs power factor correction control, realizes AC-DC (alternating current to direct current) voltage conversion and power factor adjustment. The LLC circuit as a rear stage mainly performs DC-DC conversion, realizes voltage conversion. A current sampling circuit is arranged in the on-board charger circuit to sample the output current or input current of the on-board charger circuit. In the related art, when the current sampling circuit is abnormal, the charging is abnormal, and the on-board charger cannot charge the on-board battery. SUMMARY

[0003] The present application is proposed to solve at least one of the above problems. According to a first aspect of the present application, a charging control method of an on-board charger is provided. The on-board charger includes an LLC circuit, the LLC circuit is electrically connected to an on-board battery, and the LLC circuit is electrically connected to a first sampling circuit for sampling an output current of the LLC circuit. The charging control method includes: controlling the on-board charger to charge the on-board battery; when the first sampling circuit is not failed, controlling the LLC circuit in a frequency modulation control mode; and / or when the first sampling circuit is failed, controlling the LLC circuit in a fixed frequency control mode.

[0004] In an embodiment of the present application, the controlling the LLC circuit in the frequency modulation control mode includes: controlling the output current of the LLC circuit to keep at a first target current according to a sampling current of the first sampling circuit and the first target current by using a first current loop control strategy.

[0005] In an embodiment of the present application, the charging control method further includes: when a working voltage of the on-board charger is at a first working voltage, if the sampling current of the first sampling circuit is within a first preset range, determining that the first sampling circuit is not failed; if the sampling current of the first sampling circuit is not within the first preset range, determining that the first sampling circuit is failed; and / or when the working voltage of the on-board charger is at a second working voltage, if the sampling current of the first sampling circuit is within a second preset range, determining that the first sampling circuit is not failed; if the sampling current of the first sampling circuit is not within the second preset range, determining that the first sampling circuit is failed; wherein the first working voltage is less than the second working voltage.

[0006] In one embodiment of the present application, the on-board charger further comprises an AC charging port and a PFC circuit, the AC charging port, the PFC circuit and the LLC circuit are connected in sequence; the AC charging port has a live terminal; the PFC circuit comprises a power frequency bridge arm and N high-frequency bridge arms, where N is a positive integer greater than 1, the bridge arm midpoint of each high-frequency bridge arm is electrically connected to the live terminal through an inductor, each inductor is electrically connected to a second sampling circuit for sampling the input current of the inductor, and the bridge arm midpoint of the power frequency bridge arm is electrically connected to the live terminal; the charging control method further comprises at least one of the following steps: when all the second sampling circuits are not failed, converting the AC power input by the live terminal into DC power through all the high-frequency bridge arms; when part of the second sampling circuits are failed, converting the AC power input by the live terminal into DC power through the power frequency bridge arm and the high-frequency bridge arms corresponding to the second sampling circuits that are not failed; and when all the second sampling circuits are failed, stopping charging the on-board battery.

[0007] In one embodiment of the present application, the charging control method further comprises: when the first sampling circuit is not failed and at least part of the second sampling circuits are not failed, adopting a voltage-current double-loop control strategy to control the PFC circuit to convert the AC power input by the live terminal into DC power; and / or when the first sampling circuit is failed and at least part of the second sampling circuits are not failed, adopting a second current loop control strategy to control the PFC circuit to convert the AC power input by the live terminal into DC power.

[0008] In one embodiment of the present application, the voltage-current double-loop control strategy to control the PFC circuit to convert the AC power input by the live terminal into DC power comprises: adopting a double-loop cascade control strategy of a voltage outer loop and a current inner loop to control the PFC circuit to convert the AC power input by the live terminal into DC power.

[0009] In one embodiment of the present application, the double-loop cascade control strategy of the voltage outer loop and the current inner loop to control the PFC circuit to convert the AC power input by the live terminal into DC power comprises: determining a second target current according to a target voltage and the bus voltage of the PFC circuit; dividing the second target current by N to obtain a quotient as a first sub-path target current of each high-frequency bridge arm of the N high-frequency bridge arms; and controlling the high-frequency bridge arms corresponding to the second sampling circuits that are not failed according to the first sub-path target current and the sampling currents of the second sampling circuits that are not failed, so that the bus voltage of the PFC circuit is maintained at the target voltage and the input currents of the inductors electrically connected to the second sampling circuits that are not failed are maintained at the first sub-path target current.

[0010] In one embodiment of this application, the charging control method further includes: when there are at least two channels of the second sampling circuit that have not failed, controlling the high-frequency bridge arm corresponding to each second sampling circuit that has not failed in an alternating manner according to the target current of the first sub-channel and the sampling current of each second sampling circuit that has not failed, so that the bus voltage of the PFC circuit is maintained at the target voltage, and the input current of the inductor electrically connected to each second sampling circuit that has not failed is maintained at the target current of the first sub-channel.

[0011] In one embodiment of this application, the step of using a second current loop control strategy to control the PFC circuit to convert the AC power input at the live wire terminal into DC power includes: dividing the charging power demand of the vehicle battery by the effective voltage value of the AC power input at the AC charging port, and using the quotient as a third target current; dividing the third target current by N, and using the quotient as the second sub-path target current for each of the N high-frequency bridge arms; and controlling the high-frequency bridge arm corresponding to the second sampling circuit that has not failed, based on the second sub-path target current and the sampling current of the second sampling circuit that has not failed, so that the input current of the inductor electrically connected to the second sampling circuit that has not failed is maintained at the second sub-path target current.

[0012] In one embodiment of this application, the charging control method further includes: when there are at least two channels of the second sampling circuit that have not failed, controlling the high-frequency bridge arm corresponding to each second sampling circuit that has not failed in an alternating manner according to the target current of the second sub-channel and the sampling current of each second sampling circuit that has not failed, so that the input current of the inductor electrically connected to each second sampling circuit that has not failed is maintained at the target current of the second sub-channel.

[0013] In one embodiment of this application, the charging control method further includes: when the operating voltage of the on-board charger is a first operating voltage, if the sampling current of the second sampling circuit is within a third preset range, then the second sampling circuit is determined to be not faulty; if the sampling current of the second sampling circuit is not within the third preset range, then the second sampling circuit is determined to be faulty; and / or, when the operating voltage of the on-board charger is a second operating voltage, if the sampling current of the second sampling circuit is within a fourth preset range, then the second sampling circuit is determined to be not faulty; if the sampling current of the second sampling circuit is not within the fourth preset range, then the second sampling circuit is determined to be faulty; wherein, the first operating voltage is less than the second operating voltage.

[0014] According to a second aspect of this application, a charging control device for an on-board charger is also provided. The charging control device includes a storage medium and a processor. The storage medium stores a computer program that is executed by the processor. When the computer program is executed by the processor, it causes the processor to perform any of the above-described charging control methods for the on-board charger.

[0015] According to a third aspect of this application, an on-board charger is also provided, the on-board charger comprising: an LLC circuit; wherein the LLC circuit is used to electrically connect to an on-board battery, and the LLC circuit is electrically connected to a first sampling circuit for sampling the output current of the LLC circuit; the on-board charger further comprises a charging control device for any of the above-described on-board chargers.

[0016] According to a fourth aspect of this application, a vehicle is also provided, the vehicle comprising: a charging control device for any of the above-described on-board chargers, or any of the above-described on-board chargers.

[0017] According to the vehicle-mounted charger and its charging control method and apparatus, as well as the vehicle provided in the embodiments of this application, when the first sampling circuit used to sample the output current of the LLC circuit does not fail, a frequency modulation control mode is used to control the LLC circuit; and when the first sampling circuit fails, a fixed frequency control mode is used to control the LLC circuit. Therefore, even if the first sampling circuit fails, the vehicle-mounted charger can still ensure normal charging of the vehicle battery, preventing the inability to charge the vehicle battery due to the failure of the first sampling circuit. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating a charging control method for an on-board charger according to an embodiment of the present invention;

[0020] Figure 2 This is a circuit topology diagram of an on-board charger according to an embodiment of the present invention;

[0021] Figure 3 This is a control flowchart illustrating a first current loop control strategy in frequency modulation control mode according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the control flow under a fixed-frequency control mode according to an embodiment of the present invention;

[0023] Figure 5 This is a flowchart illustrating a method for determining whether a first sampling circuit has failed, as shown in an embodiment of the present invention.

[0024] Figure 6 This is a flowchart illustrating a charging control method for an on-board charger according to another embodiment of the present invention;

[0025] Figure 7 This is a flowchart illustrating a charging control method for an on-board charger according to another embodiment of the present invention;

[0026] Figure 8 This is a flowchart illustrating a dual closed-loop cascade control strategy employing an outer voltage loop and an inner current loop, as shown in an embodiment of the present invention.

[0027] Figure 9 This is a control flowchart illustrating a dual closed-loop cascade control strategy employing an outer voltage loop and an inner current loop, as shown in another embodiment of the present invention.

[0028] Figure 10 This is a control flowchart illustrating a dual closed-loop cascade control strategy employing an outer voltage loop and an inner current loop, as shown in another embodiment of the present invention.

[0029] Figure 11 This is a control flowchart illustrating a second current loop control strategy according to an embodiment of the present invention;

[0030] Figure 12 This is a control flowchart illustrating a second current loop control strategy according to another embodiment of the present invention;

[0031] Figure 13 This is a control flowchart illustrating a second current loop control strategy according to another embodiment of the present invention;

[0032] Figure 14 This is a flowchart illustrating a method for determining whether a second sampling circuit has failed, as shown in an embodiment of the present invention.

[0033] Figure 15 This is a schematic block diagram of a charging control device for an on-board charger according to an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.

[0035] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0036] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, confirm the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0038] In related technologies, a single-phase on-board charger (OBC) includes two stages of control circuitry: a PFC circuit and an LLC circuit. The PFC circuit, acting as the front-end, primarily performs single-phase power factor calibration control, achieving AC-DC (alternating current to DC) voltage boost and power factor regulation. The LLC circuit, acting as the rear-end, performs isolated resonant control, mainly handling DC-DC conversion and enabling software switching and charging current control.

[0039] In related technologies, single-phase on-board chargers involve the sampling and control of three input currents and one output current. Current sampling typically uses a Hall effect sampling circuit. A malfunction in the Hall effect sampling circuit can lead to charging abnormalities. That is, in related technologies, a failure in any one of the current sampling circuits of a single-phase on-board charger will cause the entire single-phase on-board charger to malfunction, preventing it from charging the vehicle battery. To address at least some of the problems described above, this application proposes the following embodiments.

[0040] To fully understand this invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by this invention. Optional embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0041] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] First, let me introduce the application scenario of the charging control method of the on-board charger illustrated in this application. This charging control method of the on-board charger is applied to the process of charging the on-board battery using the on-board charger.

[0043] refer to Figure 1 and Figure 2 This application provides a charging control method for an on-board charger, wherein the on-board charger includes an LLC circuit, the LLC circuit being electrically connected to an on-board battery, and the LLC circuit being electrically connected to a first sampling circuit for sampling the output current of the LLC circuit. The control method includes:

[0044] Control the on-board charger to charge the on-board battery;

[0045] When the first sampling circuit does not fail, the LLC circuit is controlled using frequency modulation control mode; and / or,

[0046] When the first sampling circuit fails, the LLC circuit is controlled using a fixed-frequency control mode.

[0047] In the above scheme, when the first sampling circuit used to sample the output current of the LLC circuit is not faulty, a frequency modulation control mode is used to control the LLC circuit; while when the first sampling circuit fails, a fixed frequency control mode is used to control the LLC circuit. Therefore, even if the first sampling circuit fails, the on-board charger can still ensure normal charging of the vehicle battery, preventing the on-board charger from failing to charge the battery due to the failure of the first sampling circuit. The charging control method of the above-mentioned on-board charger will be described in detail below with reference to the accompanying drawings.

[0048] For example, the on-board charger may include an AC charging port for connecting to an external charging device to charge the vehicle battery. When setting the AC charging port, it can be any interface capable of electrical connection with an external charging device. For example, the charging device can be a charging station. The AC charging port can be a plug-in interface, allowing the charging gun on the charging station to be plugged into the AC charging port. For example, the AC charging port has a live wire terminal and a neutral wire terminal, meaning the on-board charger is a single-phase charger. For example, the AC charging port may also have a ground terminal. For example, refer to... Figure 2 Ua represents the live wire terminal in the AC charging port.

[0049] For example, refer to Figure 2The on-board charger may also include a PFC circuit, which is electrically connected to the AC charging port and also electrically connected to the LLC circuit. That is, the PFC circuit is electrically connected between the AC charging port and the LLC circuit, and the AC charging port, PFC circuit and LLC circuit are electrically connected in sequence.

[0050] When setting up a PFC circuit, refer to Figure 2 The PFC circuit can employ any type of power factor correction circuit. For example, the PFC circuit may include a power frequency bridge arm and N high-frequency bridge arms, where N is a positive integer greater than 1; for example, N can be equal to 2 or 3. It should be noted that a high-frequency bridge arm refers to a bridge arm whose switching transistors can be turned on and off at a frequency higher than a preset frequency threshold; while a power frequency bridge arm refers to a bridge arm whose switching transistors cannot be turned on and off at a frequency higher than a preset frequency threshold. It can be seen that a power frequency bridge arm also refers to a low-frequency bridge arm. The midpoint of each high-frequency bridge arm is electrically connected to the live wire terminal via an inductor, and each inductor is electrically connected to a second sampling circuit for sampling the input current of that inductor. The midpoint of the power frequency bridge arm is electrically connected to the live wire terminal. That is, the PFC circuit contains N high-frequency bridge arms, N inductors and N second sampling circuits. Each high-frequency bridge arm is electrically connected to an inductor, and each inductor is electrically connected to a second sampling circuit. There is a one-to-one correspondence between each second sampling circuit, each high-frequency bridge arm and each inductor.

[0051] For example, refer to Figure 2 The power frequency bridge arm and the N high-frequency bridge arms can be connected in parallel between the positive and negative buses of the PFC current. Each bridge arm in the power frequency bridge arm and the N high-frequency bridge arms contains two switches connected in series, with the midpoint of each bridge arm located at the series node between the two switches. For example, the midpoint of the power frequency bridge arm is directly electrically connected to the live wire terminal on the AC charging port. The midpoint of each high-frequency bridge arm is electrically connected to the live wire terminal on the AC charging port via an inductor. For example, each inductor is electrically connected to a second sampling circuit for sampling the input current of that inductor, to sample and measure the input current of the AC current flowing into that inductor and the high-frequency bridge arm.

[0052] For example, refer to Figure 2The total number of high-frequency bridge arms, N, can be equal to 3. The three high-frequency bridge arms are the first, second, and third high-frequency bridge arms connected in parallel. The first high-frequency bridge arm consists of switches P1 and P2 connected in series, and its midpoint is electrically connected to the live wire terminal Ua of the AC charging port through inductor L1. The second high-frequency bridge arm consists of switches P3 and P4 connected in series, and its midpoint is electrically connected to the live wire terminal Ua of the AC charging port through inductor L2. The third high-frequency bridge arm consists of switches P5 and P6 connected in series, and its midpoint is electrically connected to the live wire terminal Ua of the AC charging port through inductor L3. The power frequency bridge arm consists of switches P7 and P8 connected in series, and its midpoint is directly electrically connected to the live wire terminal Ua of the AC charging port. That is, the PFC circuit adopts a three-phase four-bridge-arm control topology, and the control signals include single-phase input voltage, three-phase input current, and PFC voltage.

[0053] When setting up the LLC circuit, refer to Figure 2 The LLC circuit can employ any type of resonant control circuit. The LLC circuit is used to electrically connect to the vehicle battery, and the LLC circuit is electrically connected to a first sampling circuit for sampling the output current of the LLC circuit. For example, see reference... Figure 2 Io represents the sampling current of the LLC circuit sampled by the first sampling circuit, i.e., Io represents the sampling current of the first sampling circuit. For example, the LLC circuit may include a primary-side bridge arm circuit, a secondary-side bridge arm circuit, and an isolation transformer. The primary-side bridge arm circuit may include two primary-side bridge arms connected in parallel. The positive bus of the primary-side bridge arm circuit is electrically connected to the positive bus of the PFC circuit, and the negative bus of the primary-side bridge arm circuit is electrically connected to the negative bus of the PFC circuit. The midpoints of the two primary-side bridge arms in the primary-side bridge arm circuit are respectively connected to the positive and negative terminals of the primary side of the isolation transformer. The secondary-side bridge arm circuit may include two secondary-side bridge arms connected in parallel. The positive bus of the secondary-side bridge arm circuit is electrically connected to the positive terminal of the vehicle battery, and the negative bus of the secondary-side bridge arm circuit is electrically connected to the negative terminal of the vehicle battery. The midpoints of the two secondary-side bridge arms in the secondary-side bridge arm circuit are respectively connected to the positive and negative terminals of the secondary side of the isolation transformer. Each of the primary and secondary bridge arms comprises two switches connected in series, with the midpoint of the bridge arm located at the series node of the two switches. For example, the switches in both the primary and secondary bridge arms can be switches capable of high-frequency control for on / off switching. The LLC circuit is electrically connected to a first sampling circuit for sampling the output current of the LLC circuit. For example, this first sampling circuit can be a current sampling circuit capable of measuring the magnitude of the output current of the LLC circuit, such as, but not limited to, a Hall effect sensor circuit.

[0054] For example, refer to Figure 2The primary-side bridge arm circuit consists of two primary-side arms, designated as the first and second primary-side arms. The first primary-side arm comprises switches Q1 and Q2 connected in series, with its midpoint electrically connected to the positive terminal of the isolation transformer's primary winding. The second primary-side arm comprises switches Q3 and Q4 connected in series, with its midpoint electrically connected to the negative terminal of the isolation transformer's primary winding. The secondary-side bridge arm circuit consists of two secondary-side arms, designated as the first and second secondary-side arms. The first secondary-side arm comprises switches Q5 and Q6 connected in series, with its midpoint electrically connected to the positive terminal of the isolation transformer's secondary winding. The second secondary-side arm comprises switches Q7 and Q8 connected in series, with its midpoint electrically connected to the negative terminal of the isolation transformer's secondary winding. In other words, the LLC circuit uses a full-bridge topology, and the control signals include output voltage and output current.

[0055] For example, before charging the vehicle battery via the on-board charger, the AC charging port needs to be electrically connected to the charging device. After the AC charging port is electrically connected to the charging device, the on-board charger is controlled to charge the vehicle battery.

[0056] During the process of controlling the on-board charger to charge the on-board battery, refer to Figure 1 and Figure 2 Depending on whether the first sampling circuit fails, different modes are used to control the LLC circuit for DC-DC conversion. For details, refer to... Figure 1 , Figure 2 and Figure 3 When the first sampling circuit does not fail, the LLC circuit is controlled using frequency modulation control mode. And / or, refer to... Figure 1 , Figure 2 and Figure 4 When the first sampling circuit fails, a fixed-frequency control mode is used to control the LLC circuit. This ensures that even if the first sampling circuit fails, the on-board charger can still charge the vehicle battery normally, preventing the battery from being unable to be charged due to the failure of the first sampling circuit. In other words, this control method can include at least one of the two modes mentioned above.

[0057] For example, when controlling an LLC circuit using frequency modulation control mode, various types of frequency modulation control strategies can be employed. For instance, refer to... Figure 3 Controlling the LLC circuit using a frequency modulation control mode may include: based on the sampling current of the first sampling circuit and the first target current, employing a first current loop control strategy to control the output current of the LLC circuit to maintain it at the first target current. For example, refer to... Figure 3In this context, Io_ref represents the first target current, and Io represents the sampling current of the first sampling circuit. This employs a single-loop current control strategy, maintaining the output current of the LLC circuit at the first target current based on the sampling current of the first sampling circuit, thereby charging the vehicle battery in a constant-current manner. It's important to note that the method of controlling the LLC circuit using frequency modulation control is not limited to the one shown above; other methods can also be used.

[0058] For example, refer to Figure 5 and Figure 7 The charging control method also includes determining whether the first sampling circuit has failed. Various methods can be used for this determination. Several methods are illustrated below.

[0059] For example, refer to Figure 5 The failure detection method for the first sampling circuit is specifically related to the operating voltage of the on-board charger. For details, please refer to... Figure 5 When the on-board charger's operating voltage is at a lower first operating voltage, if the sampling current of the first sampling circuit is within a first preset range, then the first sampling circuit is determined to be functioning correctly; if the sampling current of the first sampling circuit is not within the first preset range, then the first sampling circuit is determined to be faulty. For example, when the on-board charger's operating voltage is at the first operating voltage, the on-board charger can be in a low-voltage operating condition. And / or,

[0060] refer to Figure 5 When the on-board charger's operating voltage is at a higher second operating voltage, if the sampling current of the first sampling circuit is within a second preset range, then the first sampling circuit is determined to be functioning correctly; if the sampling current of the first sampling circuit is not within the second preset range, then the first sampling circuit is determined to be faulty. Here, the first operating voltage is lower than the second operating voltage. By employing this method, it is possible to accurately determine whether the first sampling circuit has failed, improving the accuracy of fault detection. For example, when the on-board charger's operating voltage is at the second operating voltage, the on-board charger can operate under high voltage conditions.

[0061] It should be noted that when the on-board charger operates at a lower first operating voltage, it is often used for communication handshake functions, so the sampling current value of the first sampling circuit is usually small. Conversely, when the on-board charger operates at a higher second operating voltage, it typically begins charging the vehicle battery, so the sampling current value of the first sampling circuit is usually larger. Therefore, in some embodiments, the first preset range can be smaller than the second preset range; specifically, the upper limit of the first preset range is smaller than the lower limit of the second preset range. Of course, the relationship between the first and second preset ranges is not limited to the manner shown above and is also specifically related to the functional configuration of the first and second operating voltages.

[0062] For example, refer to Figure 2 The on-board charger also includes an AC charging port and a PFC circuit, which are connected sequentially. The AC charging port has a live wire terminal. The PFC circuit includes a power frequency bridge arm and N high-frequency bridge arms, where N is a positive integer greater than 1. The midpoint of each high-frequency bridge arm is electrically connected to the live wire terminal through an inductor. Each inductor is electrically connected to a second sampling circuit for sampling the input current of that inductor. The midpoint of the power frequency bridge arm is electrically connected to the live wire terminal. At this time, reference... Figure 6 and Figure 7 The charging control method may further include at least one of the following steps: when all second sampling circuits are functioning correctly, converting the AC power input to the live wire terminal into DC power through all high-frequency bridge arms; when some second sampling circuits fail, converting the AC power input to the live wire terminal into DC power through the power frequency bridge arm and the high-frequency bridge arms corresponding to all valid second sampling circuits; and stopping charging the vehicle battery when all second sampling circuits fail. For example, if the number of high-frequency bridge arms N is 3, then the number of second sampling circuits is also 3, and these 3 second sampling circuits sample the input currents of inductors L1, L2, and L3, respectively. Wherein, Ia represents the sampling current of the second sampling circuit sampling inductor L1, Ib represents the sampling current of the second sampling circuit sampling inductor L2, and Ic represents the sampling current of the second sampling circuit sampling inductor L3.

[0063] For details, please refer to Figure 6 , Figure 7 , Figure 8 and Figure 11 If all the second sampling circuits of the N-channel second sampling circuit are not faulty, the switching transistors on the power frequency bridge arm are turned off, and the AC power input to the live wire terminal is converted into DC power through all the high frequency bridge arms.

[0064] In the case of partial failure of the N-channel second sampling circuit, refer to... Figure 6 ,Figure 7 , Figure 9 , Figure 10 , Figure 12 and Figure 13 If some of the second sampling circuits are not faulty, the switching transistors on the high-frequency bridge arm corresponding to the faulty second sampling circuit are turned off, and the AC power input to the live wire terminal is converted into DC power through the power frequency bridge arm and all the high-frequency bridge arms corresponding to the faulty second sampling circuits.

[0065] If all second sampling circuits of the N-channel second sampling circuit fail, it is determined that the PFC circuit cannot perform power factor correction control. Therefore, the switching transistors on the power frequency bridge arm and all high frequency bridge arms are turned off, and the charging of the vehicle battery is stopped.

[0066] In addition, this charging control method can also combine the failure of the first sampling circuit to adopt different control strategies for AC-to-DC power factor correction control of the PFC circuit.

[0067] For example, refer to Figure 2 , Figure 6-10 The charging control method may further include: when the first sampling circuit is not faulty and at least part of the second sampling circuit is not faulty, using a voltage-current dual-loop control strategy to control the PFC circuit to convert the AC power input at the live wire terminal to DC power. That is, when the first sampling circuit is not faulty and some or all of the second sampling circuits are not faulty, thus enabling the PFC circuit to perform power factor correction control, a voltage-current dual-loop control strategy can be used to control the PFC circuit to convert the AC power input at the live wire terminal to DC power, i.e., using a voltage-current dual-loop control strategy to control the PFC circuit to perform power factor correction control. And / or,

[0068] For example, refer to Figure 2 , Figure 6 , Figure 7 , Figure 11-13 The charging control method may further include: when the first sampling circuit fails, but at least part of the second sampling circuit does not fail, using a second current loop control strategy to control the PFC circuit to convert the AC power input at the live wire terminal to DC power. That is, when the first sampling circuit fails, but some or all of the second sampling circuits do not fail, thus enabling the PFC circuit to perform power factor correction control, a second current loop control strategy can be used to control the PFC circuit to convert the AC power input at the live wire terminal to DC power; that is, a single-loop current control strategy can be used to control the PFC circuit for power factor correction control. Various methods can be used to implement the voltage and current dual-loop control strategy for power factor correction control of the PFC circuit. Several methods are illustrated below.

[0069] For example, refer to Figure 2 ,Figure 6-10 A dual-loop voltage and current control strategy can be used to control the PFC circuit to convert the AC power input at the live wire terminal into DC power. This can include employing a dual closed-loop cascade control strategy with an outer voltage loop and an inner current loop to control the PFC circuit to convert the AC power input at the live wire terminal into DC power. This improves the power factor correction effect of the PFC circuit. Of course, in other embodiments, a parallel dual-loop voltage and current control strategy can also be used to simplify the calculations.

[0070] Regarding the dual closed-loop cascade control strategy employing an outer voltage loop and an inner current loop, there are various ways to control the PFC circuit to convert the AC power input at the live wire terminal into DC power.

[0071] For example, refer to Figure 2 , Figure 6-10 A dual closed-loop cascade control strategy, employing an outer voltage loop and an inner current loop, is used to control the PFC circuit to convert the AC power input at the live wire terminal into DC power. This can include: firstly, determining a second target current based on the target voltage and the bus voltage of the PFC circuit; for example, refer to... Figure 8-10 Vref in the diagram represents the target voltage. Then, the quotient obtained by dividing the second target current by N is used as the first sub-path target current of each of the N high-frequency bridge arms. Based on the first sub-path target current and the sampling current of the second sampling circuit that has not failed, the high-frequency bridge arm corresponding to the second sampling circuit that has not failed is controlled so that the bus voltage of the PFC circuit is maintained at the target voltage and the input current of the inductor electrically connected to the second sampling circuit that has not failed is maintained at the first sub-path target current.

[0072] Among them, reference Figure 2 , Figure 6-10 In determining the second target current based on the target voltage and the bus voltage of the PFC circuit, the target voltage can be the target output voltage of the PFC circuit, meaning the target bus voltage of the PFC circuit is stabilized at the target voltage level. The bus voltage of the PFC circuit can be measured by electrically connecting a bus capacitor Ci between the positive and negative buses of the PFC circuit. The positive terminal of the bus capacitor Ci is electrically connected to the positive bus of the PFC circuit, and the negative terminal of the bus capacitor Ci is electrically connected to the negative bus of the PFC circuit. The bus voltage of the PFC circuit is obtained by acquiring the voltage of the bus capacitor Ci. For example, refer to... Figure 8-10 In this context, Uci represents the voltage of the bus capacitor Ci, which also represents the bus voltage of the PFC circuit. Then, using the voltage outer loop control strategy within the dual closed-loop cascade control strategy (voltage outer loop and current inner loop), the second target current is determined based on the target voltage and the bus voltage of the PFC circuit.

[0073] Among them, reference Figure 2 , Figure 6-10The reason for using the quotient obtained by dividing the second target current by N as the first sub-path target current for each of the N high-frequency bridge arms is that the high-frequency bridge arms were designed from the outset with the intention of sharing the load current among multiple high-frequency bridge arms in the connection of their switching devices and wiring devices. Therefore, after determining the total second target current input to the PFC circuit, the second target current is not divided by the total number of second sampling circuits without failure, but rather by the total number of high-frequency bridge arms N. If a second sampling circuit fails, the charging power for the vehicle battery is sacrificed to ensure that the high-frequency bridge arm corresponding to the second sampling circuit without failure will not experience overload, thereby ensuring that the high-frequency bridge arms without failure can still work normally and improving the reliability and stability of the charging system.

[0074] Of course, in other embodiments, refer to Figure 2 , Figure 6-10 This step can be replaced by dividing the second target current by the total number of undisturbed second sampling circuits, and using the quotient as the first sub-path target current for the high-frequency bridge arm corresponding to the undisturbed second sampling circuit. Using this method, even with a undisturbed second sampling circuit, the charging power for the vehicle battery is kept as constant as possible by increasing the input current of the high-frequency bridge arm corresponding to the undisturbed second sampling circuit. This embodiment can be applied to circuit devices with high overload safety factors used in the switching transistors and wires of the high-frequency bridge arm.

[0075] Next, refer to Figure 2 , Figure 6-10 Then, based on the target current of the first sub-path and the sampling current of the second sampling circuit that has not failed, the high-frequency bridge arm corresponding to the second sampling circuit that has not failed is controlled to keep the bus voltage of the PFC circuit at the target voltage, and the input current of the inductor electrically connected to the second sampling circuit that has not failed is kept at the target current of the first sub-path. For example, the current inner loop control strategy in the dual closed-loop cascade control strategy of voltage outer loop and current inner loop can be adopted. Based on the target current of the first sub-path and the sampling current of the second sampling circuit that has not failed, the high-frequency bridge arm corresponding to the second sampling circuit that has not failed is controlled to keep the bus voltage of the PFC circuit at the target voltage, and the input current of the inductor electrically connected to the second sampling circuit that has not failed is kept at the target current of the first sub-path.

[0076] In controlling the high-frequency bridge arm corresponding to the undisturbed second sampling circuit based on the target current of the first sub-path and the sampling current of the undisturbed second sampling circuit, various methods can be employed. For example, refer to... Figure 2 , Figure 6-10A first PWM control signal can be generated based on the target current of the first sub-path and the sampling current of the second sampling circuit that is not faulty, to control the high-frequency bridge arm corresponding to the second sampling circuit that is not faulty. This first PWM control signal can be an SPWM wave. The number of SPWM waves included in the first PWM control signal can be the total number of the second sampling circuits that are not faulty, that is, an SPWM wave is generated for each switch on the high-frequency bridge arm corresponding to the second sampling circuit that is not faulty, to control the conduction and turn-off of the corresponding switch, thereby controlling the high-frequency bridge arm corresponding to the second sampling circuit that is not faulty, so that the bus voltage of the PFC circuit is maintained at the target voltage, and the input current of the inductor electrically connected to the second sampling circuit that is not faulty is maintained at the target current of the first sub-path.

[0077] For example, refer to Figure 2 , Figure 6-10 The charging control method may further include: when there are at least two non-failed second sampling circuits, interleaving the control of the high-frequency bridge arm corresponding to each non-failed second sampling circuit according to the target current of the first sub-circuit and the sampling current of each non-failed second sampling circuit, so that the bus voltage of the PFC circuit is maintained at the target voltage, and the input current of the inductor electrically connected to each non-failed second sampling circuit is maintained at the target current of the first sub-circuit. That is, when there are at least two non-failed second sampling circuits, it means that there are also at least two usable high-frequency bridge arms. Since the number of non-failed second sampling circuits is equal to the number of usable high-frequency bridge arms, the usable high-frequency bridge arms can be interleaved. The specific interleaving control method can be related to the number of usable high-frequency bridge arms. For example, when there are three usable high-frequency bridge arms, the modulation phase of the interleaving control method can be 120°; when there are two usable high-frequency bridge arms, the modulation phase of the interleaving control method can be 180°.

[0078] For example, refer to Figure 2 , Figure 6-9 , Figure 2 , Figure 6 There are several ways to use a second current loop control strategy to control the PFC circuit to convert the AC power input from the live wire terminal to DC power. Several setup methods are illustrated below.

[0079] For example, refer to Figure 7 , Figure 11-13 , Figure 2 , Figure 6The second current loop control strategy is used to control the PFC circuit to convert the AC power input at the live wire terminal to DC power. This can include: first, dividing the charging power demand of the vehicle battery by the effective voltage value of the AC power input at the AC charging port, and using the quotient as the third target current. For example, refer to... Figure 7 The "Power" in the text indicates the charging power required by the vehicle's battery. (Refer to...) Figure 11-13 In this context, Uac_rms represents the effective voltage value of the AC power input to the AC charging port. (Refer to...) Figure 11-13 In this context, Iref represents the third target current. Then, the quotient obtained by dividing the third target current by N is used as the second sub-target current of each of the N high-frequency bridge arms. Based on the second sub-target current and the sampling current of the second sampling circuit that has not failed, the high-frequency bridge arm corresponding to the second sampling circuit that has not failed is controlled so that the input current of the inductor electrically connected to the second sampling circuit that has not failed is kept at the second sub-target current.

[0080] Among them, reference Figure 11-13 , Figure 11-13 , Figure 2 , Figure 6 When the first sampling circuit fails, the LLC circuit needs to be switched to fixed-frequency mode, and the LLC circuit can no longer adjust its output current. Therefore, in this embodiment, a second current loop control strategy is used to control the PFC circuit, maintaining the input current of the inductor electrically connected to the undisturbed second sampling circuit at the second sub-path target current. This ensures that the PFC circuit provides a reliable and stable current input to the LLC circuit, thereby making the LLC circuit's output current as stable as possible. At this time, when determining the third target current, the quotient obtained by dividing the charging power demand of the vehicle battery by the effective voltage value of the AC power input to the AC charging port is used as the third target current, facilitating the determination of a more accurate third target current.

[0081] Among them, reference Figure 7 , Figure 11-13 , Figure 2 , Figure 6The reason for dividing the third target current by N and using the quotient as the second sub-path target current for each of the N high-frequency bridge arms is that the high-frequency bridge arms were designed from the outset with the intention of sharing the load current among multiple high-frequency bridge arms in the connection of their switching devices and wiring devices. Therefore, after determining the total third target current input to the PFC circuit, instead of dividing the third target current by the total number of compliant second sampling circuits, it is divided by the total number of high-frequency bridge arms N. If a compliant second sampling circuit exists, the charging power for the vehicle battery is sacrificed to ensure that the high-frequency bridge arm corresponding to the compliant second sampling circuit does not experience overload, thus ensuring that the compliant high-frequency bridge arms can still operate normally and improving the reliability and stability of the charging system.

[0082] Of course, in other embodiments, this step can be replaced by: dividing the third target current by the total number of non-failed second sampling circuits, and using the quotient as the second sub-path target current of the high-frequency bridge arm corresponding to the non-failed second sampling circuit. Using this method, when a failed second sampling circuit exists, the input current of the high-frequency bridge arm corresponding to the non-failed second sampling circuit is increased to ensure that the charging power for the vehicle battery remains as constant as possible. This embodiment can be applied to circuit devices with high overload safety factors used in the switching transistors and wires of the high-frequency bridge arm.

[0083] Next, refer to Figure 7 , Figure 11-13 , Figure 2 , Figure 6 Then, based on the target current of the second sub-path and the sampling current of the undisturbed second sampling circuit, the high-frequency bridge arm corresponding to the undisturbed second sampling circuit is controlled to keep the input current of the inductor electrically connected to the undisturbed second sampling circuit at the target current of the second sub-path. For example, a second current loop control strategy can be used to control the high-frequency bridge arm corresponding to the undisturbed second sampling circuit based on the target current of the second sub-path and the sampling current of the undisturbed second sampling circuit, so that the input current of the inductor electrically connected to the undisturbed second sampling circuit remains at the target current of the second sub-path.

[0084] In controlling the high-frequency bridge arm corresponding to the undone second sampling circuit based on the target current of the second sub-path and the sampling current of the undone second sampling circuit, various methods can be employed. For example, refer to... Figure 7 , Figure 11-13 , Figure 2 , Figure 6A second PWM control signal can be generated based on the target current of the second sub-path and the sampling current of the undisturbed second sampling circuit to control the high-frequency bridge arm corresponding to the undisturbed second sampling circuit. This second PWM control signal can be an SPWM wave. The number of SPWM waves included in the second PWM control signal can be the total number of undisturbed second sampling circuits, that is, an SPWM wave is generated for each switch on the high-frequency bridge arm corresponding to the undisturbed second sampling circuit to control the on and off of the corresponding switch, thereby controlling the high-frequency bridge arm corresponding to the undisturbed second sampling circuit so that the input current of the inductor electrically connected to the undisturbed second sampling circuit is maintained at the target current of the second sub-path.

[0085] For example, refer to Figure 7 , Figure 11-13 , Figure 2 , Figure 6 The charging control method may further include: when there are at least two unfailed second sampling circuits, interleaving the control of the high-frequency bridge arm corresponding to each unfailed second sampling circuit based on the target current of the second sub-circuit and the sampling current of each unfailed second sampling circuit, so that the input current of the inductor electrically connected to each unfailed second sampling circuit remains at the target current of the second sub-circuit. That is, when there are at least two unfailed second sampling circuits, it means that there are also at least two usable high-frequency bridge arms. Since the number of unfailed second sampling circuits is equal to the number of usable high-frequency bridge arms, the usable high-frequency bridge arms can be interleaved. The specific interleaving control method depends on the number of usable high-frequency bridge arms. For example, when there are three usable high-frequency bridge arms, the modulation phase of the interleaving control method can be 120°; when there are two usable high-frequency bridge arms, the modulation phase of the interleaving control method can be 180°.

[0086] For example, refer to Figure 7 , Figure 11-13 , Figure 2 and Figure 6 The charging control method may further include: determining whether each second sampling circuit has failed. There are various methods for determining whether the second sampling circuit has failed. Several methods are illustrated below.

[0087] For example, refer to Figure 7 , Figure 11-13 , Figure 2 and Figure 6The failure determination method of the second sampling circuit is specifically related to the operating voltage of the on-board charger. Specifically, the charging control method may further include: when the operating voltage of the on-board charger is a lower first operating voltage, if the sampling current of the second sampling circuit is within a third preset range, then the second sampling circuit is determined not to have failed; if the sampling current of the second sampling circuit is not within the third preset range, then the second sampling circuit is determined to have failed. For example, when the operating voltage of the on-board charger is at the first operating voltage, the on-board charger can be in a low-voltage operating condition. And / or,

[0088] refer to Figure 7 , Figure 4 , Figure 2 and Figure 6 When the on-board charger operates at a higher second operating voltage, if the sampling current of the second sampling circuit is within a fourth preset range, the second sampling circuit is determined to be functioning correctly; if the sampling current is not within the fourth preset range, the second sampling circuit is determined to be faulty. Here, the first operating voltage is lower than the second operating voltage. By employing this method, it is possible to accurately determine whether each second sampling circuit is faulty, improving the accuracy of sampling circuit fault detection. For example, when the on-board charger operates at the second operating voltage, the on-board charger can operate under high voltage conditions.

[0089] It should be noted that when the on-board charger operates at a lower first operating voltage, it is often used for communication handshake functions, so the sampling current value of the second sampling circuit is usually small. Conversely, when the on-board charger operates at a higher second operating voltage, it typically begins charging the vehicle battery, so the sampling current value of the second sampling circuit is usually larger. Therefore, in some embodiments, the third preset range can be smaller than the fourth preset range; specifically, the upper limit of the third preset range is smaller than the lower limit of the fourth preset range. Of course, the relationship between the third and fourth preset ranges is not limited to the manner shown above and is also specifically related to the functional configuration of the first and second operating voltages.

[0090] The following example, with N=3, illustrates the processing strategy control based on whether the first and second sampling circuits fail.

[0091] (I) When the first sampling circuit is not faulty, the following control strategy can be adopted depending on whether the second sampling circuit is faulty. In this case, during the following process, the LLC circuit adopts a frequency modulation control strategy, refer to... Figure 7The LLC circuit employs a first current loop frequency modulation control strategy. The frequency modulation range is determined based on the charging range and gain interval, satisfying soft switching and power control functions. The frequency modulation range of this topology is 80kHz-250kHz. The MOSFETs Q1, Q2, Q3, and Q4 in the primary-side circuit are the primary-side high-frequency modulation control transistors, while Q5, Q6, Q7, and Q8 in the secondary-side circuit are the secondary-side synchronous rectification control transistors.

[0092] (1) If the sampling currents Ia, Ib, and Ic of the three second sampling circuits are all functioning correctly, then it is determined that none of the three second sampling circuits have failed. At this point, refer to... Figure 4 The circuit employs a three-way high-frequency bridge arm interleaved control method. Specifically, the PFC circuit uses a single-phase three-way interleaved dual-loop control strategy. The modulation phase difference is 120°. Switches P1, P2, P3, P4, P5, and P6 on the three high-frequency bridge arms are high-frequency control transistors. Switches P7 and P8 on the power frequency bridge arm are off. The control algorithm follows a single-phase three-way interleaved voltage and current dual-loop control, with each channel having a power of P / 3, and a total power of P.

[0093] (2) If one of the sampling currents Ia, Ib, and Ic of the three-channel second sampling circuit fails, then it is determined that one of the three-channel second sampling circuits has failed. At this time, refer to... Figure 2 It employs a two-way high-frequency bridge arm interleaved control method. Specifically, the PFC circuit uses a single-phase, two-way interleaved dual-loop control strategy. The modulation phase difference is 180°.

[0094] Specifically, 1. If the sampling circuit Ia of sampling inductor L1 fails, then refer to Figure 6 The system employs an interleaved control method for the second and third high-frequency bridge arms, with a modulation phase of 180°. Switches P1 and P2 on the first high-frequency bridge arm are off. Switches P3, P4, P5, and P6 on the second and third high-frequency bridge arms are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm uses a single-phase, two-path interleaved voltage and current dual-loop control, with a total power of 2P / 3.

[0095] 2. If the sampling circuit Ib of sampling inductor L2 fails, an interleaved control method is adopted for the first and third high-frequency bridge arms, with a modulation phase of 180°. Switches P3 and P4 on the second high-frequency bridge arm are turned off. Switches P1, P2, P5, and P6 on the first and third high-frequency bridge arms are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase, two-way interleaved voltage and current dual-loop control, with a total power of 2P / 3.

[0096] 3. If the sampling circuit Ic of sampling inductor L3 fails, an interleaved control method is adopted for the first and second high-frequency bridge arms, with a modulation phase of 180°. Switches P5 and P6 on the third high-frequency bridge arm are turned off. Switches P1, P2, P3, and P4 on the first and second high-frequency bridge arms are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase, two-way interleaved voltage and current dual-loop control, with a total power of 2P / 3.

[0097] (3) If two of the sampling currents Ia, Ib, and Ic of the three-channel second sampling circuit fail, then it is determined that two of the three-channel second sampling circuits have failed. In this case, refer to... Figure 7 The control method employs a single high-frequency bridge arm. Specifically, the PFC circuit uses a single-phase, single-channel, dual-loop control strategy.

[0098] Specifically, 1. If the sampling circuit Ia of sampling inductor L1 fails, and the sampling circuit Ib of sampling inductor L2 fails, then refer to Figure 4 The system employs a third high-frequency bridge arm control method. Switches P1, P2, P3, and P4 on the first and second high-frequency bridge arms are off. Switches P5 and P6 on the third high-frequency bridge arm are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase voltage and current dual-loop control, with a total power of P / 3.

[0099] 2. If the sampling circuit Ia of sampling inductor L1 fails, and the sampling circuit Ic of sampling inductor L3 fails, the second high-frequency bridge arm control method is adopted. Switches P1, P2, P5, and P6 on the first and third high-frequency bridge arms are turned off. Switches P3 and P4 on the second high-frequency bridge arm are high-frequency control transistors, and P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase voltage and current dual-loop control, with a total power of P / 3.

[0100] 3. If the sampling circuit Ib of sampling inductor L2 fails and the sampling circuit Ic of sampling inductor L3 fails, the first high-frequency bridge arm control method is adopted. Switches P3, P4, P5, and P6 on the second and third high-frequency bridge arms are turned off. Switches P1 and P2 on the first high-frequency bridge arm are high-frequency control transistors, and P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase voltage and current dual-loop control, with a total power of P / 3.

[0101] (4) If three of the sampling currents Ia, Ib, and Ic in the three-channel second sampling circuit fail, then it is determined that three of the three-channel second sampling circuits have failed. At this time, the system fault protection can be reported, and all switching transistors in the PFC circuit and LLC circuit will be turned off to stop charging the vehicle battery.

[0102] (ii) When the first sampling circuit fails, the following control strategy can be adopted depending on whether the second sampling circuit fails. In the following control strategy, the quotient obtained by dividing the charging power demand of the vehicle battery by the effective value of the AC voltage input to the AC charging port is used as the third target current. For example, refer to... Figure 3 The "Power" in the text indicates the charging power required by the vehicle's battery. (Refer to...) Figure 8 In this context, Uac_rms represents the effective voltage value of the AC power input to the AC charging port. (Refer to...) Figure 9 In this context, Iref represents the third target current. At this point, during the following process, the LLC circuit employs a fixed-frequency control strategy, referencing... Figure 9 The LLC circuit employs a fixed-frequency control strategy, with the control frequency chosen at the resonant frequency to satisfy the soft-switching function; in this topology, the frequency is 150kHz. The MOSFETs Q1, Q2, Q3, and Q4 in the primary circuit are primary-side high-frequency modulation control transistors, while Q5, Q6, Q7, and Q8 in the secondary circuit are secondary-side synchronous rectification control transistors.

[0103] (1) If the sampling currents Ia, Ib, and Ic of the three second sampling circuits are all functioning correctly, then it is determined that none of the three second sampling circuits have failed. At this point, refer to... Figure 10 The circuit employs a three-way high-frequency bridge arm interleaved control method. Specifically, the PFC circuit uses a single-phase three-way interleaved dual-loop control strategy. The modulation phase difference is 120°. Switches P1, P2, P3, P4, P5, and P6 on the three high-frequency bridge arms are high-frequency control transistors. Switches P7 and P8 on the power frequency bridge arm are off. The control algorithm follows a single-phase three-way interleaved current single-loop control, with each channel having a power of P / 3, and a total power of P.

[0104] (2) If one of the sampling currents Ia, Ib, and Ic of the three-channel second sampling circuit fails, then it is determined that one of the three-channel second sampling circuits has failed. At this time, refer to... Figure 10 It employs a two-way high-frequency bridge arm interleaved control method. Specifically, the PFC circuit uses a single-phase, two-way interleaved current single-loop control strategy. The modulation phase difference is 180°.

[0105] Specifically, 1. If the sampling circuit Ia of sampling inductor L1 fails, then refer to Figure 11-13 The system employs an interleaved control method for the second and third high-frequency bridge arms, with a modulation phase of 180°. Switches P1 and P2 on the first high-frequency bridge arm are off. Switches P3, P4, P5, and P6 on the second and third high-frequency bridge arms are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm uses a single-phase, two-path interleaved current single-loop control, with a total power of 2P / 3.

[0106] 2. If the sampling circuit Ib of sampling inductor L2 fails, an interleaved control method is adopted for the first and third high-frequency bridge arms, with a modulation phase of 180°. Switches P3 and P4 on the second high-frequency bridge arm are turned off. Switches P1, P2, P5, and P6 on the first and third high-frequency bridge arms are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm uses a single-phase, two-way interleaved current single-loop control, with a total power of 2P / 3.

[0107] 3. If the sampling circuit Ic of sampling inductor L3 fails, an interleaved control method is adopted for the first and second high-frequency bridge arms, with a modulation phase of 180°. Switches P5 and P6 on the third high-frequency bridge arm are turned off. Switches P1, P2, P3, and P4 on the first and second high-frequency bridge arms are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm uses single-phase two-way interleaved current single-loop control, with a total power of 2P / 3.

[0108] (3) If two of the sampling currents Ia, Ib, and Ic of the three-channel second sampling circuit fail, then it is determined that two of the three-channel second sampling circuits have failed. In this case, refer to... Figure 11-13 The control method uses a single high-frequency bridge arm. That is, the PFC circuit adopts a single-phase, single-channel current, single-loop control strategy.

[0109] Specifically, 1. If the sampling circuit Ia of sampling inductor L1 fails, and the sampling circuit Ib of sampling inductor L2 fails, then refer to Figure 11-13 The system employs a third high-frequency bridge arm control method. Switches P1, P2, P3, and P4 on the first and second high-frequency bridge arms are off. Switches P5 and P6 on the third high-frequency bridge arm are high-frequency control transistors, while P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm uses single-phase current single-loop control, with a total power of P / 3.

[0110] 2. If the sampling circuit Ia of sampling inductor L1 fails and the sampling circuit Ic of sampling inductor L3 fails, the second high-frequency bridge arm control method is adopted. Switches P1, P2, P5, and P6 on the first and third high-frequency bridge arms are turned off. Switches P3 and P4 on the second high-frequency bridge arm are high-frequency control transistors, and P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase current single-loop control, with a total power of P / 3.

[0111] 3. If the sampling circuit Ib of sampling inductor L2 fails and the sampling circuit Ic of sampling inductor L3 fails, the first high-frequency bridge arm control method is adopted. Switches P3, P4, P5, and P6 on the second and third high-frequency bridge arms are turned off. Switches P1 and P2 on the first high-frequency bridge arm are high-frequency control transistors, and P7 and P8 on the power frequency bridge arm are power frequency control transistors. The control algorithm follows a single-phase current single-loop control, with a total power of P / 3.

[0112] (4) If three of the sampling currents Ia, Ib, and Ic in the three-channel second sampling circuit fail, then it is determined that three of the three-channel second sampling circuits have failed. At this time, the system fault protection can be reported, and all switching transistors in the PFC circuit and LLC circuit will be turned off to stop charging the vehicle battery.

[0113] By summarizing the control modes described above, it can be seen that, based on... Figure 4 and Figure 11 By identifying the validity of the sampled current signals from the first and second sampling circuits, an appropriate control mode is selected. The normal mode employs a three-way interleaved charging control strategy; failure modes 1, 2, and 3 are matched with a single-phase two-way interleaved control strategy; and failure modes 4, 5, and 6 are matched with a single-phase single-path charging control strategy. Figure 12 For specific failure conditions, the control strategy is as follows: when the output current Io is normal, LLC uses frequency modulation control; when abnormal, fixed frequency control is used. The PFC control strategy mainly identifies the AC side current signal. When the signal is normal, a three-way interleaved charging control strategy is used; when one channel fails, it can be matched to failure modes 1, 2, and 3; when two channels fail, it can be matched to failure modes 4, 5, and 6, using a single-phase charging control strategy. By identifying the validity of the current signal sampled by the software, the failure of single-channel current sampling, dual-channel current sampling, and three-channel current sampling, as well as whether the LLC current sampling has failed, are identified to select the appropriate control algorithm. See [link to relevant documentation]. Figure 12 Current failure handling strategy. When any two or three AC currents fail, and one DC output fails, the system still needs to continue operating. However, there is a lack of failure handling solutions for single-phase OBC charging systems in related technologies.

[0114] In the various embodiments shown above, when the first sampling circuit used to sample the output current of the LLC circuit is not faulty, a frequency modulation control mode is used to control the LLC circuit; while when the first sampling circuit fails, a fixed frequency control mode is used to control the LLC circuit. Therefore, even if the first sampling circuit fails, the on-board charger can still ensure normal charging of the on-board battery, preventing the on-board battery from being unable to be charged due to the failure of the first sampling circuit.

[0115] In related technologies, all three current sampling channels must be valid to meet operational requirements; failure of two or three channels will prevent operation. However, the on-board charger provided in some embodiments of this application uses a single-phase OBC charging system. To meet charging needs, when sampling failure occurs, it can implement dual-channel or single-channel charging control, and adjust the front-end and rear-end charging strategies to ensure charging functionality. That is, when the current signal sampling is abnormal, the corresponding control strategy is adjusted to maintain normal charging function. Current signal failure can be categorized as single-channel, dual-channel, or triple-channel failure of the PFC current, or failure of the LLC output current. Related technologies lack such failure handling solutions. In some embodiments of this application, by performing a rationality diagnosis on the current sampling signal of the single-phase OBC, it identifies whether the signal is normal and calculates or adjusts the control strategy in time for abnormal signals to ensure normal product charging. This strategy can also ensure normal product charging when the Hall effect sensor or sampling signal is damaged, improving product reliability and reducing after-sales maintenance costs.

[0116] Furthermore, this application embodiment also provides a charging control device for an on-board charger, which includes a storage medium and a processor. The storage medium stores a computer program executed by the processor. When the computer program is executed by the processor, the processor performs any of the above-described charging control methods for an on-board charger.

[0117] Figure 13 A schematic block diagram of a charging control device 100 for an on-board charger according to an embodiment of this application is shown. Figure 13 As shown, the charging control device 100 of the on-board charger according to an embodiment of this application may include a storage medium 110 and a processor 120. The storage medium 110 stores a computer program executed by the processor 120. When the computer program is executed by the processor 120, the processor 120 performs the charging control method of the on-board charger according to the embodiment of this application described above. Those skilled in the art can understand the specific operation of the deployment device of the charging control device 100 of the on-board charger according to the embodiment of this application in conjunction with the foregoing content. For the sake of brevity, it will not be described again here. The storage medium 110 may include, for example, a memory card of a smartphone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disc read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. A computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0118] Furthermore, this application embodiment also provides an on-board charger, which includes: an LLC circuit; wherein the LLC circuit is used to electrically connect to an on-board battery, and the LLC circuit is electrically connected to a first sampling circuit for sampling the output current of the LLC circuit; the on-board charger also includes a charging control device of any of the above-mentioned on-board chargers.

[0119] For example, the on-board charger may include an AC charging port for connecting to an external charging device to charge the vehicle battery. For example, the AC charging port has a live wire terminal, meaning the on-board charger is a single-phase on-board charger.

[0120] For example, refer to Figure 6 The on-board charger may also include a PFC circuit, which is electrically connected to the AC charging port and also electrically connected to the LLC circuit. That is, the PFC circuit is electrically connected between the AC charging port and the LLC circuit, and the AC charging port, PFC circuit and LLC circuit are electrically connected in sequence.

[0121] In addition, this application also provides a vehicle, as shown in the embodiments. Figure 7 Figure 6 Figure 6 Figure 15 Figure 15 Figure 2 Figure 1-11 The vehicle includes: a charging control device for any of the above-mentioned on-board chargers, or any of the above-mentioned on-board chargers. For example, the vehicle can be a vehicle equipped with an on-board battery, such as, but not limited to, an electric vehicle, a hybrid electric vehicle, or a gas-electric hybrid vehicle. For example, the on-board battery can be a vehicle's power battery or an energy storage battery.

[0122] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A charging control method for an on-board charger, the on-board charger comprising an LLC circuit, the LLC circuit being electrically connected to an on-board battery, and the LLC circuit being electrically connected to a first sampling circuit for sampling the output current of the LLC circuit; characterized in that, The charging control method includes: Control the on-board charger to charge the on-board battery; When the first sampling circuit is not faulty, the LLC circuit is controlled using a frequency modulation control mode; and / or, When the first sampling circuit fails, the LLC circuit is controlled using a fixed-frequency control mode.

2. The charging control method as described in claim 1, characterized in that, The method of controlling the LLC circuit using frequency modulation control mode includes: Based on the sampling current of the first sampling circuit and the first target current, a first current loop control strategy is adopted to control the output current of the LLC circuit to remain at the first target current.

3. The charging control method as described in claim 1, characterized in that, Also includes: When the on-board charger's operating voltage is at a first operating voltage, if the sampling current of the first sampling circuit is within a first preset range, then the first sampling circuit is determined to be functioning correctly; if the sampling current of the first sampling circuit is not within the first preset range, then the first sampling circuit is determined to be faulty; and / or, When the operating voltage of the on-board charger is at the second operating voltage, if the sampling current of the first sampling circuit is within the second preset range, it is determined that the first sampling circuit has not failed; if the sampling current of the first sampling circuit is not within the second preset range, it is determined that the first sampling circuit has failed. Wherein, the first operating voltage is less than the second operating voltage.

4. The charging control method as described in claim 1, characterized in that, The on-board charger also includes an AC charging port and a PFC circuit, wherein the AC charging port, the PFC circuit, and the LLC circuit are connected in sequence; the AC charging port has a live wire terminal; the PFC circuit includes a power frequency bridge arm and N high frequency bridge arms, wherein N is a positive integer greater than 1, the midpoint of each high frequency bridge arm is electrically connected to the live wire terminal through an inductor, each inductor is electrically connected to a second sampling circuit for sampling the input current of that inductor, and the midpoint of the power frequency bridge arm is electrically connected to the live wire terminal; The charging control method further includes at least one of the following steps: When all the second sampling circuits are functioning correctly, the AC power input to the live wire terminal is converted to DC power through all the high-frequency bridge arms. When a portion of the second sampling circuit fails, the AC power input to the live wire terminal is converted to DC power through the power frequency bridge arm and the high frequency bridge arms corresponding to all the second sampling circuits that have not failed. When all of the second sampling circuits fail, charging of the vehicle battery is stopped.

5. The charging control method as described in claim 4, characterized in that, Also includes: When the first sampling circuit is not faulty, and at least part of the second sampling circuit is not faulty, a voltage-current dual-loop control strategy is used to control the PFC circuit to convert the AC power input at the live wire terminal to DC power; and / or, When the first sampling circuit fails and at least part of the second sampling circuit does not fail, a second current loop control strategy is used to control the PFC circuit to convert the AC power input at the live wire terminal into DC power.

6. The charging control method as described in claim 5, characterized in that, The method of using a voltage and current dual-loop control strategy to control the PFC circuit to convert the AC power input at the live wire terminal into DC power includes: A dual closed-loop cascade control strategy with an outer voltage loop and an inner current loop is adopted to control the PFC circuit to convert the AC power input at the live wire terminal into DC power.

7. The charging control method as described in claim 6, characterized in that, The dual closed-loop cascade control strategy employing an outer voltage loop and an inner current loop controls the PFC circuit to convert the AC power input at the live wire terminal into DC power, including: The second target current is determined based on the target voltage and the bus voltage of the PFC circuit; The quotient obtained by dividing the second target current by N is used as the first sub-target current of each of the N high-frequency bridge arms. Based on the target current of the first sub-path and the sampling current of the second sampling circuit that has not failed, the high-frequency bridge arm corresponding to the second sampling circuit that has not failed is controlled so that the bus voltage of the PFC circuit is maintained at the target voltage, and the input current of the inductor electrically connected to the second sampling circuit that has not failed is maintained at the target current of the first sub-path.

8. The charging control method as described in claim 7, characterized in that, Also includes: When there are at least two channels of the second sampling circuit that have not failed, the high-frequency bridge arm corresponding to each second sampling circuit that has not failed is controlled alternately according to the target current of the first sub-channel and the sampling current of each second sampling circuit that has not failed, so that the bus voltage of the PFC circuit is maintained at the target voltage, and the input current of the inductor electrically connected to each second sampling circuit that has not failed is maintained at the target current of the first sub-channel.

9. The charging control method as described in claim 5, characterized in that, The second current loop control strategy is used to control the PFC circuit to convert the AC power input at the live wire terminal into DC power, including: The quotient obtained by dividing the charging power demand of the vehicle battery by the effective value of the AC voltage input to the AC charging port is used as the third target current. The quotient obtained by dividing the third target current by N is used as the second sub-target current of each of the N high-frequency bridge arms. Based on the target current of the second sub-path and the sampling current of the second sampling circuit that has not failed, the high-frequency bridge arm corresponding to the second sampling circuit that has not failed is controlled so that the input current of the inductor electrically connected to the second sampling circuit that has not failed is maintained at the target current of the second sub-path.

10. The charging control method as described in claim 9, characterized in that, When there are at least two channels of the second sampling circuit that have not failed, the high-frequency bridge arm corresponding to each channel of the second sampling circuit that has not failed is controlled alternately according to the target current of the second sub-channel and the sampling current of each channel of the second sampling circuit that has not failed, so that the input current of the inductor electrically connected to each channel of the second sampling circuit that has not failed is kept at the target current of the second sub-channel.

11. The charging control method as described in claim 4, characterized in that, Also includes: When the on-board charger operates at a first operating voltage, if the sampling current of the second sampling circuit is within a third preset range, then the second sampling circuit is determined to be functioning correctly; if the sampling current of the second sampling circuit is not within the third preset range, then the second sampling circuit is determined to be faulty; and / or, When the on-board charger operates at the second operating voltage, if the sampling current of the second sampling circuit is within the fourth preset range, it is determined that the second sampling circuit has not failed; if the sampling current of the second sampling circuit is not within the fourth preset range, it is determined that the second sampling circuit has failed. Wherein, the first operating voltage is less than the second operating voltage.

12. A charging control device for an on-board charger, characterized in that, include: A storage medium and a processor, wherein the storage medium stores a computer program executed by the processor, the computer program, when executed by the processor, causes the processor to perform the charging control method of the on-board charger as described in any one of claims 1 to 11.

13. An on-board charger, characterized in that, include: LLC circuit; wherein the LLC circuit is used to electrically connect to the vehicle battery, and the LLC circuit is electrically connected to a first sampling circuit for sampling the output current of the LLC circuit; The charging control device for the on-board charger as described in claim 12.

14. A vehicle, characterized in that, include: The charging control device for the on-board charger as described in claim 12, or the on-board charger as described in claim 13.

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