Power conversion device and charging device

Abstract

This application provides a power conversion device and a charging device. The power conversion device includes an AC-DC conversion circuit, a power controller, and a circulating current controller. The power controller controls the AC-DC conversion circuit to convert received AC power into DC power before outputting it. The circulating current controller sends a synchronization signal to other power conversion devices via a Controller Area Network (CAN) bus. The synchronization signal is used to synchronize the other power conversion devices with the carrier wave of the power conversion device provided in this application. The technical solution provided in this application can suppress circulating currents between multiple parallel-connected power conversion devices, which is beneficial to improving the operational stability of the charging device.

Description

Technical Field

[0001] This application relates to the energy field, and more specifically, to a power conversion device and a charging device. Background Technology

[0002] With the rapid development of new energy vehicles, the application of car charging equipment as a supporting facility is becoming increasingly common. Car charging equipment mainly includes alternating current-to-direct current (AC-DC) converters and direct current-to-direct current (DC-DC) converters. The AC-DC converter converts the alternating current output from the power grid into direct current, while the DC-DC converter converts the direct current output from the AC-DC converter into direct current charging energy, thereby charging new energy vehicles.

[0003] In practical use, as the requirements for charging speed of new energy vehicles gradually increase, multiple AC-DC conversion devices connected in parallel are generally set in the car charging equipment. Each AC-DC conversion device performs power conversion processing on the AC power output from the grid to improve the power conversion capability of the car charging equipment from AC to DC power, thereby realizing high-power charging of new energy vehicles by the car charging equipment.

[0004] However, most AC-DC converters in car charging equipment are non-isolated, and circulating currents can easily form between multiple AC-DC converters connected in parallel. Circulating currents increase losses in the AC-DC power conversion devices, reduce power conversion efficiency, and thus affect the operational stability of the car charging equipment. Summary of the Invention

[0005] This application provides a power conversion device and a charging device that can suppress circulating currents between multiple power conversion devices connected in parallel, thereby improving the operational stability of the charging device.

[0006] In a first aspect, a power conversion device is provided, comprising: an AC-DC conversion circuit; a power controller connected to the AC-DC conversion circuit, the power controller being used to control the AC-DC conversion circuit to receive AC power and convert the AC power into a first DC power for output; and a circulating current controller being used to send a synchronization signal to other power conversion devices via a controller area network (CAN) bus, the synchronization signal being used to synchronize the carrier waves of the other power conversion devices with the carrier wave of the power conversion device.

[0007] In the above technical solution, when the power conversion device provided in this application embodiment is connected in parallel with other power conversion devices, the power conversion device provided in this application embodiment can be used as the master power conversion device, and the other power conversion devices can be used as slave power conversion devices. By setting an independent circulating current controller in the master power conversion device, the circulating current controller sends a synchronization signal to each slave power conversion device through the CAN bus to synchronize the carrier waves of the master power conversion device and the slave power conversion devices. In this way, the high-frequency circulating current component in the circulating current between the power conversion devices connected in parallel can be suppressed, which is beneficial to reducing the losses of each power conversion device, ensuring the power conversion efficiency of each power conversion device, and thus improving the operational stability of the power conversion devices connected in parallel. Moreover, the above technical solution does not require additional hardware equipment, has low cost, and is conducive to production.

[0008] Furthermore, the power conversion device provided in this application embodiment communicates and interacts with other power conversion devices via a CAN bus to achieve the transmission of synchronization signals. The network topology is relatively simple, the communication efficiency is high, and it is also more conducive to low-cost production.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the circulating current controller includes a first master timer, which is configured to adjust the period of the carrier of the power conversion device to synchronize with the period of a target carrier based on the triggering of the edge of the synchronization signal, the target carrier period being synchronized with the period of the carrier of the other power conversion device.

[0010] The target carrier period can be preset in the circulation controller.

[0011] It is understood that edge triggering of the synchronization signal can refer to triggering on the rising edge of the synchronization signal or triggering on the falling edge of the synchronization signal, and this application does not impose any restrictions on this.

[0012] In the above technical solution, in the power conversion device provided in this application embodiment, the master timer in the circulating current controller can be triggered by a synchronization signal to adjust the period of the carrier of the power conversion device to synchronize with the period of the target carrier. Since the period of the target carrier is also synchronized with the periods of the carriers of other power conversion devices, the period of the carrier of the power conversion device provided in this application embodiment is synchronized with the periods of the carriers of other power conversion devices. Therefore, when the power conversion device provided in this application embodiment is connected in parallel with other power conversion devices, the carrier of the power conversion device provided in this application embodiment can be synchronized with the carriers of other power conversion devices.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, the circulating current controller further includes a first slave timer connected to the first master timer; the first master timer is further configured to send a first trigger signal to the first slave timer when the count value of the first master timer is the period value of the target carrier period, the first trigger signal being used to indicate that the count value of the first slave timer be reset.

[0014] It is understood that the number of first slave timers can be multiple, such as 5 or 6, and this application does not limit this.

[0015] In the above technical solution, the first master timer in the circulating current controller uses the first trigger signal to periodically synchronize with the first slave timer so that the first master timer and the first slave timer output signals with the same frequency and phase, thereby realizing signal synchronization within the power conversion device.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the circulating current controller further includes a synchronization timer connected to the first master timer and the slave power conversion device. The synchronization timer is used to send the synchronization signal to the first master timer and the slave power conversion device when the count value of the synchronization timer is a first period value.

[0017] Understandably, the first period value can be the period value of the synchronization signal. In one example, the first period value can be greater than the period value of the target carrier period.

[0018] In the above technical solution, the power conversion device provided in this application embodiment can periodically send synchronization signals to the first master timer and other power conversion devices through the synchronization timer in the circulating current controller. By using the triggering of the synchronization signal, the period of its own carrier is adjusted to synchronize with the period of the target carrier, thereby achieving period synchronization with the carriers of other power conversion devices.

[0019] In conjunction with the first aspect, in some implementations of the first aspect, the power conversion device further includes a circulating current detection circuit, the AC-DC conversion circuit including multiple switches; the circulating current detection circuit is connected to the input terminal of the AC-DC conversion circuit and the circulating current controller, the circulating current detection circuit is used to detect the circulating current value at the input terminal of the AC-DC conversion circuit and transmit the circulating current value to the circulating current controller; the circulating current controller is used to receive a first modulation wave from the power controller, adjust the first modulation wave according to the circulating current value to obtain a second modulation wave, the second modulation wave is used to determine a drive signal, the drive signal is used to control the on-time of the multiple switches.

[0020] Understandably, in practice, the circulating current controller can send the second modulation wave to the power controller, which then determines the drive signal based on the second modulation wave.

[0021] In the above technical solution, by setting a circulating current detection circuit in the power conversion device, the circulating current value input to the AC-DC conversion circuit can be detected in real time. The circulating current controller can compensate and adjust the modulation wave output by the power controller according to the circulating current value, and send the adjusted modulation wave to the power controller. Then, the power controller controls the conduction time of multiple switches in the AC-DC conversion circuit by using the drive signal generated by the adjusted modulation wave, so that the low-frequency circulating current component in the AC-DC conversion circuit reaches a preset circulating current threshold, which can be, for example, 0. In this way, when multiple power conversion devices provided in this application embodiment are connected in parallel, the low-frequency circulating current component in the circulating current between each power conversion device can be suppressed, which is beneficial to reducing the loss of each power conversion device, ensuring the power conversion efficiency of each power conversion device, and thus improving the operational stability of the power conversion devices connected in parallel.

[0022] In conjunction with the first aspect, in some implementations of the first aspect, the circulating current controller is specifically used to: determine the circulating current deviation based on the circulating current value and a preset circulating current threshold; perform calculations and adjustments on the circulating current deviation to obtain a first compensation amount; and superimpose the first compensation amount with the first modulation wave to obtain the second modulation wave.

[0023] In the above technical solution, the circulating current controller can determine the deviation between the circulating current value and the preset circulating current threshold, and then determine the compensation amount for adjusting the first modulation wave output by the power controller based on this deviation. This helps ensure that the power controller, based on the drive signal determined by the adjusted second modulation wave, can control the on-time of multiple switches in the AC-DC conversion circuit to bring the low-frequency circulating current component in the AC-DC conversion circuit down to the preset circulating current threshold, thereby suppressing the low-frequency circulating current component.

[0024] In some embodiments, the operation adjustment includes any one of proportional operation, proportional-integral operation, and proportional-integral-differential operation.

[0025] In conjunction with the first aspect, in some implementations of the first aspect, the circulating current controller is further configured to send the second modulation wave to the power controller; the power controller is further configured to determine the drive signal based on the second modulation wave and the carrier wave of the power conversion device.

[0026] In the above technical solution, the power controller can adjust the duty cycle of the drive signal by comparing the compensated and adjusted second modulation wave with the carrier of the power conversion device, thereby controlling the conduction time of multiple switches in the AC-DC conversion circuit through the drive signal, so that the low-frequency circulating current component in the AC-DC conversion circuit reaches the preset circulating current threshold.

[0027] Secondly, a power conversion device is provided, comprising: an AC-DC conversion circuit; a power controller connected to the AC-DC conversion circuit, the power controller being used to control the AC-DC conversion circuit to receive AC power and convert the AC power into a first DC power for output; and a circulating current controller being used to receive synchronization signals from other power conversion devices via a controller area network (CAN) bus, the synchronization signals being used to synchronize the carrier wave of the power conversion device with the carrier wave of the other power conversion devices.

[0028] In the above technical solution, when the power conversion device provided in this application embodiment is connected in parallel with other power conversion devices, the power conversion device provided in this application embodiment can be used as the slave power conversion device, and the other power conversion devices can be used as the master power conversion devices. By setting an independent circulating current controller in the slave power conversion device, the circulating current controller receives a synchronization signal from the master power conversion device through the CAN bus, so that the carrier of the slave power conversion device is synchronized with the carrier of the master power conversion device. In this way, the high-frequency circulating current component in the circulating current between the power conversion devices connected in parallel can be suppressed, which is beneficial to reducing the loss of each power conversion device, ensuring the power conversion efficiency of each power conversion device, and thus improving the operational stability of the power conversion devices connected in parallel. Moreover, the above technical solution does not require additional hardware equipment, has low cost, and is conducive to production.

[0029] Furthermore, the power conversion device provided in this application embodiment communicates and interacts with other power conversion devices via a CAN bus to achieve the transmission of synchronization signals. The network topology is relatively simple, the communication efficiency is high, and it is also more conducive to low-cost production.

[0030] In conjunction with the second aspect, in some implementations of the second aspect, the circulating current controller includes a second master timer, which is used to adjust the period of the carrier of the power conversion device to synchronize with the period of a target carrier based on the triggering of the edge of the synchronization signal, the period of the target carrier being synchronized with the period of the carrier of the other power conversion device.

[0031] In the above technical solution, in the power conversion device provided in this application embodiment, the master timer in the circulating current controller can be triggered by a synchronization signal to adjust the period of the carrier of the power conversion device to synchronize with the period of the target carrier. Since the period of the target carrier is also synchronized with the periods of the carriers of other power conversion devices, the period of the carrier of the power conversion device provided in this application embodiment is synchronized with the periods of the carriers of other power conversion devices. Therefore, when the power conversion device provided in this application embodiment is connected in parallel with other power conversion devices, the carrier of the power conversion device provided in this application embodiment can be synchronized with the carriers of other power conversion devices.

[0032] In conjunction with the second aspect, in some implementations of the second aspect, the circulating current controller further includes a second slave timer connected to the second master timer; the second master timer is further configured to send a second trigger signal to the second slave timer when the count value of the second master timer is the period value of the target carrier period, the second trigger signal being used to indicate that the count value of the second slave timer be reset so that the second master timer is synchronized with the second slave timer.

[0033] In the above technical solution, the second master timer in the circulating current controller uses the second trigger signal to periodically synchronize with the second slave timer so that the second master timer and the second slave timer output signals with the same frequency and phase, thereby realizing signal synchronization within the power conversion device.

[0034] In conjunction with the second aspect, in some implementations of the second aspect, the power conversion device further includes a circulating current detection circuit, the AC-DC conversion circuit including multiple switches; the circulating current detection circuit is connected to the input terminal of the AC-DC conversion circuit and the circulating current controller, the circulating current detection circuit is used to detect the circulating current value at the input terminal of the AC-DC conversion circuit and transmit the circulating current value to the circulating current controller; the circulating current controller is used to receive a first modulation wave from the power controller, adjust the first modulation wave according to the circulating current value to obtain a second modulation wave, the second modulation wave is used to determine a drive signal, the drive signal is used to control the on-time of the multiple switches.

[0035] In conjunction with the second aspect, in some implementations of the second aspect, the circulating current controller is specifically used to: determine the circulating current deviation based on the circulating current value and a preset circulating current threshold; perform calculations and adjustments on the circulating current deviation to obtain a first compensation amount; and superimpose the first compensation amount with the first modulation wave to obtain the second modulation wave.

[0036] In some embodiments, the operation adjustment includes any one of proportional operation, proportional-integral operation, and proportional-integral-differential operation.

[0037] In conjunction with the second aspect, in some implementations of the second aspect, the circulating current controller is further configured to send the second modulation wave to the power controller; the power controller is further configured to determine the drive signal based on the second modulation wave and the carrier wave of the power conversion device.

[0038] Thirdly, a charging device is provided, comprising: a plurality of power conversion devices and a DC bus, wherein the plurality of power conversion devices are arranged in parallel, each of the plurality of power conversion devices comprising: an AC-DC conversion circuit; a power controller connected to the AC-DC conversion circuit, the power controller being used to control the AC-DC conversion circuit to receive AC power, convert the AC power into a first DC power, and output it through the DC bus; a circulating current controller; wherein the plurality of power conversion devices includes a master power conversion device and at least one slave power conversion device, the circulating current controller of the master power conversion device being a master circulating current controller, the circulating current controller of the slave power conversion device being a slave circulating current controller, the master circulating current controller being used to send a synchronization signal to the slave circulating current controller via a controller area network (CAN) bus, the synchronization signal being used to synchronize the carrier wave of the slave power conversion device with the carrier wave of the master power conversion device.

[0039] In the above technical solution, by configuring multiple power conversion devices in the charging device as a master power conversion device and at least one slave power conversion device, the master circulating current controller of the master power conversion device sends a synchronization signal to the slave circulating current controller of the slave power conversion device via a CAN bus, so that the carrier wave of each slave power conversion device is synchronized with the carrier wave of the master power conversion device. This suppresses high-frequency circulating current components in the circulating current between the power conversion devices in the charging device, which helps reduce the losses of each power conversion device, ensures the power conversion efficiency of each power conversion device, and thus improves the operational stability of the charging device. Furthermore, the above technical solution does not require additional hardware equipment, has low cost, and is easy to manufacture.

[0040] In addition, the power conversion devices in the charging device communicate with each other via a CAN bus to achieve the transmission of synchronization signals. The network topology is relatively simple, the communication efficiency is high, and it is also more conducive to low-cost production.

[0041] In conjunction with the third aspect, in some implementations of the third aspect, the master circulating current controller includes a first master timer, and the slave circulating current controller includes a second master timer; the first master timer is used to adjust the period of the carrier of the master power conversion device to synchronize with the period of the target carrier based on the triggering of the edge of the synchronization signal; the second master timer is used to adjust the period of the carrier of the slave power conversion device to synchronize with the period of the target carrier based on the triggering of the edge of the synchronization signal.

[0042] In conjunction with the third aspect, in some implementations of the third aspect, the master circulating current controller further includes a first slave timer, and the slave circulating current controller further includes a second slave timer. The first slave timer is connected to the first master timer, and the second slave timer is connected to the second master timer. The first master timer is further configured to send a first trigger signal to the first slave timer when the count value of the first master timer is the period value of the target carrier period. The first trigger signal is used to reset the count value of the first slave timer so as to synchronize the first master timer and the first slave timer. The second master timer is further configured to send a second trigger signal to the second slave timer when the count value of the second master timer is the period value of the target carrier period. The second trigger signal is used to indicate that the count value of the second slave timer is reset so as to synchronize the second master timer and the second slave timer.

[0043] In conjunction with the third aspect, in some implementations of the third aspect, the main circulating current controller further includes a synchronization timer connected to the first main timer and the second main timer. The synchronization timer is used to send the synchronization signal to the first main timer and the second main timer when the count value of the synchronization timer is the first period value.

[0044] In conjunction with the third aspect, in some implementations of the third aspect, the power conversion device further includes a circulating current detection circuit, the AC-DC conversion circuit including multiple switches; the circulating current detection circuit is connected to the input terminal of the AC-DC conversion circuit and the circulating current controller; the circulating current detection circuit is used to detect the circulating current value at the input terminal of the AC-DC conversion circuit and transmit the circulating current value to the circulating current controller; the circulating current controller is used to receive a first modulation wave from the power controller, adjust the first modulation wave according to the circulating current value to obtain a second modulation wave, the second modulation wave is used to determine a drive signal, the drive signal is used to control the on-time of the multiple switches.

[0045] In conjunction with the third aspect, in some implementations of the third aspect, the circulating current controller is specifically used to: determine the circulating current deviation based on the circulating current value and a preset circulating current threshold; perform calculations and adjustments on the circulating current deviation to obtain a first compensation amount; and superimpose the first compensation amount with the first modulation wave to obtain the second modulation wave.

[0046] In conjunction with the third aspect, in some implementations of the third aspect, the operational adjustment includes any one of proportional operation, proportional-integral operation, and proportional-integral-differential operation.

[0047] In conjunction with the third aspect, in some implementations of the third aspect, the circulating current controller is further configured to send the second modulation wave to the power controller; the power controller is further configured to determine the drive signal based on the second modulation wave and the carrier wave of the power conversion device.

[0048] In conjunction with the third aspect, in some implementations of the third aspect, the charging device further includes an energy storage unit connected to the DC bus, and the AC-DC conversion circuit is specifically used to output the first DC power to the energy storage unit through the DC bus.

[0049] In conjunction with the third aspect, in some implementations of the third aspect, the charging device further includes a DC-DC converter; the input terminal of the DC-DC converter is connected to the DC bus, and the output terminal of the DC-DC converter is used to connect to the vehicle; the DC-DC converter is used to receive the first DC power through the DC bus, convert the first DC power into a second DC power, and output it to the vehicle to supply power to the vehicle.

[0050] In conjunction with the third aspect, in some implementations of the third aspect, the charging device further includes at least one charging terminal; the at least one charging terminal is connected to the DC-DC converter; wherein each of the at least one charging terminal is used to connect to a vehicle so that the DC-DC converter charges the vehicle connected to the charging terminal through each charging terminal.

[0051] Fourthly, a charging system is provided, comprising a charging device and a vehicle as described in any one of the third aspects above, the charging device being used to charge the vehicle.

[0052] For the beneficial effects of the second to fourth aspects, please refer to the beneficial effects of the first aspect mentioned above, which will not be repeated here. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of a charging system provided in an embodiment of this application.

[0054] Figure 2 yes Figure 1 The diagram shows the electrical connections of the charging system.

[0055] Figure 3 This is a schematic diagram of the structure of a power conversion device provided in an embodiment of this application.

[0056] Figure 4 This is a schematic diagram of the structure of a charging device provided in an embodiment of this application.

[0057] Figure 5 This is a specific example of a master circulating controller 423 and a slave circulating controller 433 provided in the embodiments of this application.

[0058] Figure 6This is a synchronization timing diagram of an example synchronization signal provided in an embodiment of this application.

[0059] Figure 7 This is a schematic diagram of the structure of a charging device provided in this application.

[0060] Figure 8 This is a specific example of a charging device provided in the embodiments of this application.

[0061] Figure 9 This is a specific example of an AC-DC conversion circuit provided in the embodiments of this application.

[0062] Figure 10 This is a specific example of an AC-DC conversion circuit provided in the embodiments of this application.

[0063] Figure 11 This is a schematic diagram of another charging device provided in an embodiment of this application. Detailed Implementation

[0064] To facilitate understanding, the terminology used in the embodiments of this application will be introduced first.

[0065] Circulating current: This refers to the current flowing between multiple power conversion devices connected in parallel. Because this current does not flow to the load / grid, it is called circulating current. Circulating current can include low-frequency and high-frequency components, with the low-frequency component having a lower frequency than the high-frequency component.

[0066] Three-phase alternating current: can be a power system consisting of three AC circuits with the same frequency, equal potential amplitude, and a phase difference of 120 degrees.

[0067] To facilitate understanding of the embodiments of this application, the following points will be explained before introducing the embodiments of this application.

[0068] In the description of the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a signal transmission achieved through a direct or indirect connection between the two electrical components. For example, the connection between A and B can be understood as A and B being directly connected, or it can be understood as A and B being indirectly connected through one or more other electrical components.

[0069] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. "And / or" in this document is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0070] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined as "first" or "second" may knowingly or implicitly include one or more features. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more, and "at least one" and "one or more" refer to one, two, or more than two. The singular expressions "a," "an," "the," "the," "this," and "this" are intended to also include expressions such as "one or more," unless the context explicitly indicates otherwise.

[0071] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0072] First, to facilitate understanding of the power conversion device provided in the embodiments of this application, the application scenarios of the power conversion device will be introduced below.

[0073] Figure 1 This is a schematic diagram of the structure of a charging system 10 provided in an embodiment of this application. Figure 2 yes Figure 1 The diagram shows the electrical connections of the charging system 10.

[0074] It should be understood that Figure 2 In Chinese, solid lines are used to represent power transmission lines, for example... Figure 2 The solid line connecting the external power grid 20 and the power conversion device 1111 represents the power transmission line from the external power grid 20 to the power conversion device 1111, where AC power is input from the power grid 20.

[0075] Combination Figure 1 and Figure 2 The charging system 10 may include a charging device 11 and a vehicle 12. The charging device 11 may include a power conversion module 111 and at least one charging terminal 112 connected to the power conversion module 111, and each of the at least one charging terminal 112 is connected to the vehicle 12. In a specific implementation, one charging terminal 112 may be connected to one vehicle 12, or multiple charging terminals 112 may be connected to one vehicle 12.

[0076] The power conversion module 111 can receive AC power input from the external power grid 20 and convert it into stable DC power before supplying it to the charging terminal 112. The charging terminal 112 can supply the stable DC power converted by the power conversion module 111 to the vehicle 12 to charge the vehicle 12.

[0077] like Figure 2As shown, the power conversion module 111 may include multiple power conversion devices 1111, DC-DC conversion devices 1112, and DC bus 1113.

[0078] The input terminals of multiple power conversion devices 1111 can be connected to the external power grid 20, and the output terminals of the multiple power conversion devices 1111 can be connected to the DC bus 1113. That is, the multiple power conversion devices 1111 can be connected in parallel between the external power grid 20 and the DC bus 1113. The multiple power conversion devices 111 can be used to receive AC power from the external power grid 20, convert the AC power to DC power, and then output it through the DC bus 1113. In other words, the power conversion devices 111 can be AC-DC conversion devices.

[0079] The input terminal of the DC-DC converter 1112 can be connected to the DC bus 1113, and the output terminal of the DC-DC converter 1112 can be connected to the charging terminal 112. The DC-DC converter 1112 can receive DC power output from multiple power conversion devices 1111 through the DC bus 1113, and further convert the DC power into DC power suitable for the vehicle 12, and then transmit it to the vehicle 12 through the charging terminal 112 for charging the vehicle 12.

[0080] The charging terminal 112 may include a housing, a human-machine interface, a charging control unit, and a metering and billing unit, etc. The charging terminal 112 can be used to interact with the vehicle 12, transmit energy, and perform metering and billing.

[0081] Vehicle 12 can be a vehicle powered by electricity. Vehicle 12 can be a new energy vehicle, which can be a pure electric vehicle (pure EV / battery EV), a hybrid electric vehicle (HEV), a range-extended electric vehicle (REEV), or a plug-in hybrid electric vehicle (PHEV), etc.

[0082] In the aforementioned power conversion module 111, multiple power conversion devices 1111 are connected in parallel, and each power conversion device 1111 performs power conversion processing on the AC power output from the external power grid 20 to improve the AC to DC power conversion capability of the charging device 11, thereby enabling the charging device 11 to charge the vehicle 12 at high power.

[0083] However, the power conversion device 1111 is generally non-isolated, and circulating currents (such as...) can easily occur between multiple power conversion devices 1111 connected in parallel. Figure 2 (As shown by the dashed arrow in the image). Circulating current can generally be divided into high-frequency circulating current components and low-frequency circulating current components. The high-frequency circulating current component is mainly caused by the asynchrony of the carrier signals of multiple power conversion devices 1111, while the low-frequency circulating current component is mainly caused by the inconsistency of the modulation wave signals due to differences in the hardware parameters and control parameters of multiple power conversion devices 1111. However, both high-frequency and low-frequency circulating current components will increase the losses of the power conversion device 1111 and reduce the power conversion efficiency, thereby affecting the operational stability of the charging device 11.

[0084] To suppress circulating currents among multiple power conversion devices 1111, it is common practice to add additional hardware isolation devices, such as passive filtering devices or isolation transformers at the input of each power conversion device 1111, to isolate the circulating current path. However, the above methods will increase the cost and size of the charging device 11.

[0085] Based on the above, embodiments of this application provide a power conversion device and a charging device that can suppress circulating currents between multiple power conversion devices connected in parallel, thereby improving the operational stability of the charging device.

[0086] Figure 3 This is a schematic diagram of the structure of a power conversion device 300 provided in an embodiment of this application.

[0087] It should be understood that Figure 3 In Chinese, solid lines represent power transmission lines, and dashed lines represent signal transmission lines. For example... Figure 3 The solid line connecting the input terminal of the power conversion device 300 and the AC-DC conversion circuit 310 represents the power transmission line from the input terminal of the power conversion device 300 to the AC-DC conversion circuit 310. The dashed line connecting the power controller 320 and the AC-DC conversion circuit 310 represents the signal transmission line for the control signal transmission between the power controller 320 and the AC-DC conversion circuit 310.

[0088] See Figure 3 The power conversion device 300 may include an AC-DC conversion circuit 310, a power controller 320, and a circulating current controller 330.

[0089] The input terminal of the AC-DC conversion circuit 310 can be connected to an external power grid (not shown in the figure) to receive AC power output from the external power grid. The AC-DC conversion circuit 310 can perform power conversion on the AC power to obtain a first DC power, and output the first DC power through the output terminal of the AC-DC conversion circuit 310.

[0090] It is understood that, in the embodiments of this application, the alternating current output from the external power grid can be referred to as mains power, which is usually three-phase alternating current.

[0091] The power controller 320 can be connected to the AC-DC conversion circuit 310. The power controller 320 can be used to control the AC-DC conversion circuit 310 to receive AC power and convert the AC power into DC power before outputting it.

[0092] In some embodiments, the power controller 320 may be any one of a central processor (CPU), a network processor (NP), a digital signal processor (DSP), a micro controller unit (MCU), and a programmable logic device (PLD).

[0093] The circulating current controller 330 can be used to send synchronization signals to other power conversion devices via a controller area network (CAN) bus, or the circulating current controller 330 can also be used to receive synchronization signals from other power conversion devices via a CAN bus.

[0094] Specifically, the power conversion device 300 can be connected in parallel with other power conversion devices to form a parallel system. Both the power conversion device 300 and the other power conversion devices can receive AC power from the external power grid and convert it into DC power before outputting it, giving the parallel system a high AC-to-DC power conversion capability. Furthermore, in this parallel system, the power conversion devices connected in parallel can achieve carrier synchronization through the transmission of synchronization signals. The power conversion device that sends the synchronization signal can be called the master power conversion device, and the power conversion device that receives the synchronization signal can be called the slave power conversion device.

[0095] In one possible scenario, in this parallel system, power conversion device 300 can be used as the primary power conversion device, and other power conversion devices can be used as secondary power conversion devices. For example... Figure 3As shown, in the power conversion device 300, which serves as the primary power conversion device, the circulating current controller 330 can communicate with other power conversion devices serving as secondary power conversion devices via a CAN bus to send synchronization signals to the other power conversion devices. These synchronization signals are used to synchronize the carrier waves of the other power conversion devices with the carrier wave of the power conversion device 300. It is understood that in this parallel system, the number of other power conversion devices serving as secondary power conversion devices can be one or more.

[0096] In another possible scenario, in this parallel system, power conversion device 300 can act as a slave power conversion device, and other power conversion devices can act as master power conversion devices. In the slave power conversion device 300, the circulating current controller 330 can communicate with the other master power conversion devices via a CAN bus to receive synchronization signals sent by the other power conversion devices. These synchronization signals are used to synchronize the carrier waves of power conversion device 300 with the carrier waves of other power conversion devices. It is understood that in this parallel system, the number of power conversion devices 300 acting as slave power conversion devices can be one or more.

[0097] It is also understood that, in the embodiments of this application, carrier synchronization can refer to the carriers of two power conversion devices connected in parallel having the same phase. For example, the carrier synchronization of power conversion device 300 with the carriers of other power conversion devices can refer to the carriers of power conversion device 300 having the same phase with the carriers of other power conversion devices.

[0098] For example, the circulating controller 330 may be a DSP.

[0099] In this embodiment, when the power conversion device 300 is connected in parallel with other power conversion devices, the circulating current controller 330 installed in the power conversion device 300 can send synchronization signals to other power conversion devices via the CAN bus, or receive synchronization signals sent by other power conversion devices via the CAN bus, so as to synchronize the carrier wave of the power conversion device 300 with the carrier waves of other power conversion devices. This suppresses high-frequency circulating current components in the circulating current between the parallel-connected power conversion devices, which helps reduce the losses of each power conversion device, ensures the power conversion efficiency of each power conversion device, and thus improves the operational stability of the parallel-connected power conversion devices. Furthermore, the above technical solution does not require additional hardware equipment, has low cost, and is easy to manufacture.

[0100] Furthermore, currently, multiple power conversion devices often communicate and interact via Ethernet to transmit signals. Ethernet uses switches, which generally require switches with many interfaces, resulting in a large number of interconnecting cables and a relatively complex network topology. High-performance switches also lead to higher costs. However, in this embodiment, the power conversion device 300 communicates directly with other power conversion devices via a CAN bus without using a switch, achieving synchronization signal transmission. This results in a simpler network topology, higher communication efficiency, and is more conducive to low-cost production.

[0101] The specific implementation method of carrier synchronization between the power conversion device 300 and other power conversion devices via synchronization signals will be described below; the above is only a brief explanation.

[0102] Continue reading Figure 3 In some embodiments, the power conversion device 300 may further include a circulating current detection circuit 340, and the AC-DC conversion circuit 310 may include multiple switches. The circulating current detection circuit 340 may be connected to the input terminal of the AC-DC conversion circuit 310 and the circulating current controller 330. The circulating current detection circuit 340 can be used to detect the circulating current value at the input terminal of the AC-DC conversion circuit 310 and transmit the circulating current value to the circulating current controller 330.

[0103] It is understandable that the circulating current value can refer to the magnitude of the current flowing into the AC-DC conversion circuit 310 from the other power conversion devices when the power conversion device 300 is connected in parallel with other power conversion devices.

[0104] The circulating current controller 330 can be connected to the power controller 320 for signal transmission. The circulating current controller 330 can receive a first modulated wave from the power controller 320 and adjust the first modulated wave according to the circulating current value obtained from the circulating current detection circuit 340 to obtain a second modulated wave. This second modulated wave can be used to determine a drive signal, which controls the on-time of multiple switches in the AC-DC conversion circuit 210.

[0105] In a specific implementation, the circulating current controller 330 can send the adjusted second modulation wave to the power controller 320, and the power controller 320 can determine the driving signal based on the second modulation wave and the carrier wave of the power conversion device 300.

[0106] It should be noted that the switches in the embodiments of this application can refer to one or more of various types of switching transistors, such as metal oxide semiconductor field effect transistors (MOSFETs), bipolar junction transistors (BJTs), insulated gate bipolar transistors (IGBTs), and silicon carbide (SiC) transistors. This application does not impose any limitations on this. The packaging of each switching transistor can be a single-transistor package or a multi-transistor package.

[0107] In this embodiment, by providing a circulating current detection circuit 340 in the power conversion device 300, the circulating current value input to the AC-DC conversion circuit 310 can be detected in real time. The circulating current controller 330 can compensate and adjust the first modulation wave output by the power controller 320 according to the circulating current value, and send the adjusted second modulation wave to the power controller 320. Furthermore, the power controller 320 controls the conduction time of multiple switches in the AC-DC conversion circuit 310 by using the drive signal generated by the second modulation wave, so that the low-frequency circulating current component in the AC-DC conversion circuit 310 reaches a preset circulating current threshold, which can be, for example, 0. In this way, when multiple power conversion devices 300 are connected in parallel, the low-frequency circulating current component in the circulating current between the power conversion devices 300 can be suppressed, which helps to reduce the loss of the power conversion devices 300, ensure the power conversion efficiency of the power conversion devices 300, and thus improve the operational stability of the multiple power conversion devices 300 connected in parallel.

[0108] The power conversion device provided in the embodiments of this application has been briefly introduced above. The power conversion device provided in the embodiments of this application will be further described below in conjunction with the charging device provided in the embodiments of this application.

[0109] Figure 4 This is a schematic diagram of the structure of a charging device 400 provided in an embodiment of this application. It should be understood that... Figure 4 Solid lines in the diagram represent power transmission lines, while dashed lines represent signal transmission lines.

[0110] See Figure 4 The charging device 400 may include a DC bus 410 and multiple power conversion devices, which may be connected in parallel between the external power grid (not shown) and the DC bus 410. It is understood that the DC bus 410 may include a positive bus and a negative bus, and the output terminal of each of the multiple power conversion devices may be connected to both the positive and negative buses.

[0111] The plurality of power conversion devices may include a main power conversion device 420 and at least one slave power conversion device 430. The main power conversion device 420 and the slave power conversion device 430 may each be a power conversion device 300.

[0112] It is understood that the main power conversion device 420 and the slave power conversion device 430 can be pre-defined among multiple power conversion devices connected in parallel. For example, among multiple power conversion devices, the power conversion device with the smallest device identification number can be set as the main power conversion device 420, and the other power conversion devices besides the one with the smallest device identification number can be set as slave power conversion devices 430.

[0113] It should be noted that the above method of setting the main power conversion device 420 and the slave power conversion device 430 according to the device identification number is only illustrative. In actual implementation, the method of setting the main power conversion device 420 and the slave power conversion device 430 among multiple power conversion devices can be adjusted according to actual production and design requirements.

[0114] For example, the multiple power conversion devices may include a main power conversion device 420 and one, two, or three slave power conversion devices 430. It should be understood that, for ease of description and understanding, the embodiments of this application are described using the example of multiple power conversion devices including a main power conversion device 420 and one slave power conversion device 430.

[0115] The main power conversion device 420 may include an AC-DC conversion circuit 421, a power controller 422, and a main circulating current controller 423. The slave power conversion device 430 may include an AC-DC conversion circuit 431, a power controller 432, and a slave circulating current controller 433. The input terminals of the AC-DC conversion circuits 421 and 431 can be connected in parallel with the external power grid, and the output terminals of the AC-DC conversion circuits 421 and 431 can be connected in parallel with the DC bus 410. That is, the AC-DC conversion circuits 421 and 431 can be connected in parallel between the external power grid and the DC bus 410.

[0116] The master circulating current controller 423 can communicate with the slave circulating current controller 433 via a CAN bus, thereby enabling the master circulating current controller 423 to send a synchronization signal to the slave circulating current controller 433 via the CAN bus. This synchronization signal can be used to synchronize the carrier wave of the slave power converter 430 with the carrier wave of the master power converter 420.

[0117] In specific implementations, in some embodiments, the main power conversion device 420 may include an isolator 4241, a CAN transceiver 4242, and a CAN interface 4243, while the slave power conversion device 430 may include an isolator 4341, a CAN transceiver 4342, and a CAN interface 4343. The main circulating current controller 423, isolator 4241, CAN transceiver 4242, and CAN interface 4243 are connected sequentially, and the slave circulating current controller 433, isolator 4341, CAN transceiver 4342, and CAN interface 4343 are connected sequentially. Both CAN interfaces 4243 and 4343 are connected to a CAN bus, enabling the main circulating current controller 423 to communicate with the slave circulating current controller 433 via the CAN bus, thus achieving the transmission of synchronization signals.

[0118] For the details regarding the main power conversion device 420 and the slave power conversion device 430 mentioned above, please refer to [link to relevant documentation]. Figure 3 The embodiments shown are not described in detail here.

[0119] In some embodiments, the master circulating current controller 423 and the slave circulating current controller 433 may use a synchronization signal based on multiple timers to achieve carrier synchronization between the master power conversion device 420 and the slave power conversion device 430.

[0120] The following description, in conjunction with the accompanying drawings, illustrates the specific method by which the master circulating current controller 423 and the slave circulating current controller 433 achieve carrier synchronization based on multiple timers and using synchronization signals.

[0121] Figure 5 This is a specific example diagram of a master circulating controller 423 and a slave circulating controller 433 provided in an embodiment of this application. It should be understood that... Figure 5 The dashed lines in the diagram represent signal transmission lines.

[0122] See Figure 5 In some embodiments, the master circulating current controller 423 may include a first master timer 4231, a first slave timer 4232, and a synchronization timer 4233, while the slave circulating current controller 433 may include a second master timer 4331 and a second slave timer 4332. The first master timer 4231 and the first slave timer 4231 are connected, and the second master timer 4331 and the second slave timer 4332 are connected. Furthermore, the first master timer 4231 and the second master timer 4331 are each connected to the synchronization timer 4233.

[0123] The synchronization timer 4233 can be used to send a synchronization signal to the first master timer 4231 and the second master timer 4331 when the count value of the synchronization timer 4233 is the first period value. The first period value can be the period value of the synchronization signal.

[0124] The first master timer 4231 can be used to adjust the period of the carrier of the master power converter 420 to synchronize with the target carrier period based on the edge triggering of the synchronization signal. The second master timer 4331 can also be used to adjust the period of the carrier of the slave power converter 430 to synchronize with the target carrier period based on the edge triggering of the synchronization signal. Thus, the periods of the carriers of both the master power converter 420 and the slave power converter 430 are synchronized with the target carrier period; that is, the carriers of the master power converter 420 and the slave power converter 430 are synchronized.

[0125] It is understandable that the target carrier period can be a pre-set carrier period, and the period value of the target carrier period can be flexibly adjusted according to actual design requirements.

[0126] In practical implementation, the target carrier period and target count value can be preset in the first master timer 4231 and the second master timer 4331. The target count value can be the count value from 0 to a preset period point within the target carrier period. The preset period point can be, for example, 1 / 2 or 1 / 3 of the target carrier period value.

[0127] The first master timer 4231 can be triggered by the edge of the synchronization signal to acquire a first count value. The first count value can be a count value from 0 to a preset period point within a main carrier period, where the main carrier period can be the period of the carrier of the main power conversion device 420. The first master timer 4231 can fine-tune the period value of the main carrier period by comparing the first count value with the target count value, so that the main carrier period and the target carrier period are synchronized; that is, the period of the carrier of the main power conversion device 420 is synchronized with the target carrier period.

[0128] Similarly, the second master timer 4331 can be triggered by the edge of the synchronization signal to acquire a second count value. The second count value can be a count value from 0 to a preset period point within a carrier period, where the carrier period can be the period of the carrier from the power conversion device 430. The second master timer 4331 can fine-tune the period value of the carrier period by comparing the second count value with the target count value, so that the carrier period of the power conversion device 430 is synchronized with the target carrier period.

[0129] Thus, the carrier wave of the master power conversion device 420 is synchronized with the carrier wave of the slave power conversion device 430.

[0130] It is understandable that edge triggering of a synchronization signal can refer to triggering on the rising edge of the synchronization signal, or it can refer to triggering on the falling edge of the synchronization signal. For example, as... Figure 6As shown, the rising edge of the synchronization signal is used as the trigger, and the first master timer 4231 and the second master timer 4331 can respectively acquire the first count value and the second count value.

[0131] It is also understandable that in the charging device 400, both the main circulating current controller 423 and the slave circulating current controller 433 include a synchronization timer, so that any one of the multiple power conversion devices in the charging device 400 can send a synchronization signal as the main power conversion device according to actual production and design requirements.

[0132] In some embodiments, the first master timer 4231 can be used to send a first trigger signal to the first slave timer 4232 when the count value of the first master timer 4231 is the period value of the target carrier period. This first trigger signal can be used to instruct the first slave timer 4232 to reset its count value. Accordingly, in response to the first trigger signal, the first slave timer 4232 can reset its own count value, synchronizing the first master timer 4231 and the first slave timer 4232, so that the master timer and slave timer within the main power conversion device 420 can output signals of the same frequency and phase, thereby achieving signal synchronization within the main power conversion device 420. Similarly, the second master timer 4331 can be used to send a second trigger signal to the second slave timer 4332 when the count value of the second master timer 4331 is the period value of the target carrier period. The second trigger signal can be used to indicate the reset of the count value of the second slave timer 4332, thereby synchronizing the second master timer 4331 and the second slave timer 4332, so that the master timer and slave timer in the slave power conversion device 430 output signals with the same frequency and phase, thereby achieving signal synchronization in the slave power conversion device 430.

[0133] It is understood that, in the embodiments of this application, resetting the count value can refer to resetting the count value to 0.

[0134] It is also understood that, in the embodiments of this application, the number of the first slave timer 4232 and the second slave timer 4332 can be multiple and equal. For example, the number of the first slave timer 4232 and the second slave timer 4332 can be 5 each, or the number of the first slave timer 4232 and the second slave timer 4332 can be 6 each.

[0135] For example, the master timer and slave timer mentioned above can be high resolution timers (HRTIM).

[0136] In the charging device 400 provided in this embodiment, by configuring multiple power conversion devices in the charging device 400 as a master power conversion device and at least one slave power conversion device, the master circulating current controller of the master power conversion device sends a synchronization signal to the slave circulating current controller of the slave power conversion device via a CAN bus, so that the carrier wave of each slave power conversion device is synchronized with the carrier wave of the master power conversion device. This suppresses high-frequency circulating current components in the circulating current between the power conversion devices in the charging device 400, which helps reduce the losses of each power conversion device, ensures the power conversion efficiency of each power conversion device, and thus improves the operational stability of the charging device. Furthermore, the above technical solution does not require additional hardware equipment, has low cost, and is easy to manufacture.

[0137] In addition, the power conversion devices in the charging device 400 communicate with each other via a CAN bus to achieve the transmission of synchronization signals. The network topology is relatively simple, the communication efficiency is high, and it is also more conducive to low-cost production.

[0138] Figure 7 This is a schematic diagram of another charging device 400 provided in an embodiment of this application. It should be understood that... Figure 7 Solid lines in the diagram represent power transmission lines, while dashed lines represent signal transmission lines.

[0139] It should also be understood that Figure 7 The charging device 400 shown includes Figures 4 to 6 Most of the technical features of the charging device 400 shown are described below. Figure 7 and Figure 4 The differences between them will be described, and the similarities will not be repeated.

[0140] See Figure 7 In some embodiments, the main power conversion device 420 may further include a circulating current detection circuit 424, and the AC-DC conversion circuit 421 may include multiple switches. The circulating current detection circuit 424 may be connected to the input terminal of the AC-DC conversion circuit 421 and the main circulating current controller 423. The circulating current detection circuit 424 can be used to detect the circulating current value at the input terminal of the AC-DC conversion circuit 421 and transmit the circulating current value to the main circulating current controller 423. The main circulating current controller 423 can be used to receive a first modulation wave from the power controller 422 and adjust the first modulation wave according to the circulating current value to obtain a second modulation wave. This second modulation wave can be used to determine a drive signal, which is used to control the on-time of the multiple switches in the AC-DC conversion circuit 421.

[0141] In one possible instance, the main circulation controller 423 can specifically be used for:

[0142] The circulation deviation is determined based on the circulation value and the preset circulation threshold.

[0143] The circulation deviation is calculated and adjusted to obtain the first compensation amount;

[0144] The first compensation amount and the first modulation wave output by the power controller 422 are superimposed to obtain the second modulation wave.

[0145] For example, the preset circulation threshold can be 0. The operation adjustment can be, for example, any one of proportional (P) operation, proportional integral (PI) operation, and proportional integral derivative (PID) operation.

[0146] Understandably, in specific implementation, the main circulating current controller 423 can use a preset circulating current threshold as a target, determine the deviation between the circulating current value and the preset circulating current threshold, determine a first compensation amount to adjust the first modulation wave output by the power controller 422 based on the deviation, and then compensate and adjust the first modulation wave through the first compensation amount to obtain the second modulation wave.

[0147] In some embodiments, the main circulating current controller 423 can also be used to send the second modulation wave to the power controller 422. The power controller 422 can determine the drive signal based on the second modulation wave and the carrier wave of the main power conversion device 420.

[0148] In one possible example, the power controller 422 may include a pulse width modulation (PWM) unit, which can be used to compare the compensated and adjusted second modulated wave with the carrier wave of the main power conversion device 420, and adjust the duty cycle of the drive signal, so that the drive signal can control the on-time of multiple switches in the AC-DC conversion circuit 421, so that the low-frequency circulating current component in the AC-DC conversion circuit 421 reaches a preset circulating current threshold.

[0149] Similarly, in some embodiments, the power conversion device 430 may also include a circulating current detection circuit 434. The circulating current detection circuit 434 may be connected to the input of the AC-DC conversion circuit 431 and the circulating current controller 433.

[0150] For a detailed description of how the driving signal from the power conversion device 430 is determined by the circulating current detection circuit 434, please refer to the relevant description of the main power conversion device 420 above, which will not be repeated here.

[0151] In the charging device 400 provided in this embodiment, each power conversion device (e.g., the main power conversion device 420 and the slave power conversion device 430) is equipped with a circulating current detection circuit. This circuit detects the circulating current value input to the AC-DC conversion circuit in real time and transmits this value to a circulating current controller. The circulating current controller can adjust the modulation wave output by the power controller based on a preset circulating current threshold, and then send the adjusted modulation wave back to the power controller. Furthermore, the power controller generates a drive signal using the adjusted modulation wave to control the on-time of multiple switches in the AC-DC conversion circuit, ensuring that the low-frequency circulating current component in the AC-DC conversion circuit reaches the preset circulating current threshold. This helps suppress the low-frequency circulating current component in the charging device 400, thereby improving the operational stability of the charging device 400.

[0152] Continue reading Figure 7 In some embodiments, the charging device 400 may further include an energy storage unit 440, which may be connected to a DC bus 410. Thus, the output terminals of the AC-DC conversion circuit 421 and the AC-DC conversion circuit 431 can be connected to the energy storage unit 440 via the DC bus 410. The first DC power output by the AC-DC conversion circuits 421 and 431 can be transmitted to the energy storage unit 440 via the DC bus 410, forming an energy pool. The energy storage unit 440 may be, for example, a photovoltaic device and / or an energy storage device.

[0153] It is understood that the photovoltaic device in the embodiments of this application can be implemented in any way that can achieve photovoltaic function. For example, the photovoltaic device may include at least one photovoltaic array, each of which is connected to the DC bus 410.

[0154] It is also understood that the energy storage device in the embodiments of this application can be implemented in any way that can realize the function of storing electrical energy. For example, the energy storage device can be an energy storage battery pack or an energy storage converter.

[0155] In this embodiment, in a light-energy storage access scenario, by superimposing energy storage units on the DC bus, the first DC power output from multiple power conversion devices can be stored in the energy storage units, achieving superimposed light and energy storage on the DC bus side. When the charging device 400 is used to charge a vehicle, it can convert the energy in the energy storage units into DC power suitable for the vehicle, resulting in high energy conversion efficiency.

[0156] The following description, in conjunction with the accompanying drawings, provides an exemplary account. Figure 7 A specific example of the charging device 400 shown.

[0157] Figure 8 This is a specific example of a charging device 500 provided in the embodiments of this application. It should be understood that... Figure 8 Solid lines in the diagram represent power transmission lines, while dashed lines represent signal transmission lines.

[0158] It should also be understood that the charging device 500 can be Figure 7 A specific example of the charging device 400 shown.

[0159] See Figure 8 The charging device 500 may include a main power conversion device 510, a slave power conversion device 520, a positive bus, and a negative bus. The main power conversion device 510 may include an AC-DC conversion circuit 511, a power controller 512, a main circulating current controller 513, and a circulating current detection circuit 514.

[0160] The following are specific examples of some structures in the main power conversion device 510.

[0161] AC-DC conversion circuit 511:

[0162] For example, see Figure 8 The AC-DC conversion circuit 511 can be a three-phase T-type interleaved Vienna rectifier circuit. The AC-DC conversion circuit 511 can include an input terminal, three sets of dual-path power factor correction (PFC) conversion circuits (i.e., dual-path PFC conversion circuit 1, dual-path PFC conversion circuit 2 and dual-path PFC conversion circuit 3) and a capacitor circuit.

[0163] The input terminal may include three phase lines: a first phase line U, a second phase line V, and a third phase line W. Each phase line can be used to receive a corresponding phase of AC power, thus the AC-DC conversion circuit 511 can receive three-phase AC power from the external power grid. The first phase line U, the second phase line V, and the third phase line W can each be connected to a set of dual-path PFC conversion circuits. Each set of dual-path PFC conversion circuits is also connected to the midpoint of the capacitor in the capacitor circuit. The first terminal of the capacitor circuit can be connected to the positive bus, and the second terminal of the capacitor branch can be connected to the negative bus. Each set of dual-path PFC conversion circuits has the same structure. Each set of dual-path PFC conversion circuits may include an inductor, two windings of an autotransformer, two switching bridge arms, and two diode bridge arms. The capacitor circuit may include capacitors C1 and C2 connected in series.

[0164] Specifically, such as Figure 8 As shown, taking a dual-channel PFC conversion circuit 1 as an example, the PFC conversion circuit 1 may include an inductor L A The two windings T of the autotransformer A1and T A2 The system comprises three bridge arms: switch arm 1, switch arm 2, diode arm 1, and diode arm 2. Switch arm 1 includes a series-connected switching transistor S. a1 and switching transistor S a2 The switch bridge arm 2 includes a series-connected switch transistor S. a3 and switching transistor S a4 Diode bridge arm 1 includes diodes D connected in series. a1 and diode D a3 Diode bridge arm 2 includes diodes D connected in series. a2 and diode D a4 Inductor L A The left end is connected to the first phase line U, and the inductor L A The right end is connected to the winding T of the autotransformer. A1 and T A2 The left end is connected. The winding T of the autotransformer. A1 The right end can be connected to the left end of switch bridge arm 1 and diode bridge arm 1 respectively, and the winding T of the autotransformer A2 The right end of switch arm 1 can be connected to the left end of switch arm 2 and diode arm 2, respectively. The right ends of switch arm 1 and switch arm 2 can be connected to the midpoint of the capacitor in the capacitor circuit. Diode arm 1 and diode arm 2 can be connected in parallel between the upper and lower ends of the capacitor circuit. The upper end of the capacitor circuit can be connected to the positive bus, and the lower end of the capacitor circuit can be connected to the negative bus.

[0165] Accordingly, the dual-path PFC conversion circuit 2 may include an inductor L B The two windings T of the autotransformer B1 and T B2 series-connected switching transistors S b1 and switching transistor S b2 series-connected switching transistors S b3 and switching transistor S b4 Diode D connected in series b1 and diode D b3 Diode D connected in series b2 and diode D b4 The specific connections of the circuit components mentioned above are similar to the connection structure of PFC conversion circuit 1. Please refer to the relevant description of PFC conversion circuit 1 above, which will not be repeated here.

[0166] Accordingly, the PFC conversion circuit 3 may include an inductor L C The two windings T of the autotransformer c1 and T c2 series-connected switching transistors S c1 and switching transistor S c2 series-connected switching transistors Sc3 and switching transistor S c4 Diode D connected in series c1 and diode D c3 Diode D connected in series c2 and diode D c4 The specific connections of the circuit components mentioned above are similar to the connection structure of PFC conversion circuit 1. Please refer to the relevant description of PFC conversion circuit 1 above, which will not be repeated here.

[0167] Optionally, in the AC-DC conversion circuit 511, at least some of the diodes mentioned above can be replaced with controllable switching transistors.

[0168] Understandably, in the AC-DC conversion circuit 511, the three sets of dual-path PFC conversion circuits can be used to receive three-phase AC power from the external power grid, convert the three-phase AC power into first DC power, and then output it through the positive bus and negative bus.

[0169] Main Circulation Controller 513:

[0170] The main circulating current controller 513 may include a comparison unit 5131, an arithmetic control unit 5132, and a compensation unit 5133.

[0171] The comparison unit 5131 can be used to determine the circulating current deviation based on the circulating current value and a preset circulating current threshold. The calculation control unit 5132 can be used to calculate and adjust the circulating current deviation to obtain a first compensation amount. The calculation control unit 5132 can be any one of a P controller, a PI controller, and a PID controller. The compensation unit 5133 can be used to superimpose the first compensation amount and the first modulation wave output by the power controller 512 to adjust and compensate the first modulation wave to obtain a second modulation wave. The first and second modulation waves can be three-phase modulation waves. The first modulation wave can include a first A-phase modulation wave, a first B-phase modulation wave, and a first C-phase modulation wave, and the second modulation wave can include a second A-phase modulation wave, a second B-phase modulation wave, and a second C-phase modulation wave. The compensation unit 5133 can transmit the obtained three-phase second modulation wave to the power controller 512, so that the power controller 512 can determine the drive signal based on the second modulation wave and the carrier wave of the main power conversion device 510. The drive signal can be a three-phase drive signal, which can include an A-phase drive signal, a B-phase drive signal, and a C-phase drive signal. Each phase drive signal can be used to control the on-time of multiple switches in two switching bridge arms of a dual-path PFC converter circuit. For example, the A-phase drive signal can be used to control the switching transistor S in the dual-path PFC converter circuit 1. a1 S a2The conduction time of phase B, the drive signal of phase B, can be used to control the switching transistor S in the dual-path PFC conversion circuit 2. b1 S b2 The conduction time of phase C, the drive signal of phase C, can be used to control the switching transistor S in the dual-channel PFC conversion circuit 3. c1 S c2 The conduction time is adjusted so that the low-frequency circulating current component in the three sets of dual-path PFC conversion circuits can reach the preset circulating current threshold.

[0172] Furthermore, the synchronization timer (not shown in the figure) in the main circulating current controller 513 can also send a synchronization signal to the slave circulating current controller 523 via the CAN bus to synchronize the main power conversion device 510 and the slave power conversion device 510.

[0173] Circulating current detection circuit 514:

[0174] The circulating current detection circuit 514 can be connected to the input terminal of the AC-DC conversion circuit 511 to detect the circulating current value input to the AC-DC conversion circuit 511 in real time. In some embodiments, the input terminal of the circulating current detection circuit 514 can be a single-phase input or a multi-phase input. For example, see [link to documentation]. Figure 8 The circulating current detection circuit 514 can be a three-phase input.

[0175] Continue reading Figure 8 The power conversion device 520 may include an AC-DC conversion circuit 521, a power controller 522, a circulating current controller 523, and a circulating current detection circuit 524.

[0176] It is understood that the topology of the power conversion device 520 is the same as that of the main power conversion device 510. For specific examples of the AC-DC conversion circuit 521, power controller 522, circulating current controller 523 and circulating current detection circuit 524, please refer to the relevant description of the main power conversion device 510 above, which will not be repeated here.

[0177] Figure 9 This is a specific example of an AC-DC conversion circuit 600 provided in the embodiments of this application. It should be understood that the AC-DC conversion circuit 600 can be an AC-DC conversion circuit 511 or an AC-DC conversion circuit 512.

[0178] and Figure 8 The illustrated embodiment is similar in that, Figure 9 In the illustrated embodiment, the AC-DC conversion circuit 600 may also include an input terminal, a three-phase dual-path PFC conversion circuit (i.e., dual-path PFC conversion circuit 1, dual-path PFC conversion circuit 2 and dual-path PFC conversion circuit 3) and a capacitor circuit.

[0179] and Figure 8 The difference between the illustrated embodiment and the one shown is that, in Figure 9 In the illustrated embodiment, the AC-DC conversion circuit 600 can be a three-phase type-I interleaved Vienna rectifier circuit. Within the AC-DC conversion circuit 600, each dual-path PFC conversion circuit can include an inductor, two windings of an autotransformer, and two switching bridge arms.

[0180] Specifically, such as Figure 9 As shown, taking a dual-channel PFC conversion circuit 1 as an example, the PFC conversion circuit 1 may include an inductor L A The two windings T of the autotransformer A1 and T A2 Switching bridge arm 1 and switching bridge arm 2. Switching bridge arm 1 includes a switching transistor S. a1 S a2 Diode D a1 D a2 D a3 and D a4 Switching bridge arm 2 includes switching transistor S a3 S a4 diode D a5 D a6 D a7 and D a8 Inductor L A The left end is connected to the first phase line U, and the inductor L A The right end is connected to the winding T of the autotransformer. A1 and T A2 The left end is connected. The winding T of the autotransformer. A1 The right end can be connected to switch bridge arm 1, and the winding T of the autotransformer A2 The right end can be connected to switch arm 2. Switch arm 1 and switch arm 2 can be connected in parallel between the upper and lower ends of the capacitor circuit, respectively.

[0181] Accordingly, the dual-path PFC conversion circuit 2 may include an inductor L B The two windings T of the autotransformer B1 and T B2 Switch S b1 S b2 S b3 and S b4 diode D b1 D b2 D b3 D b4 D b5 D b6 D b7 and D b8The specific connections of the circuit components are similar to those of the dual-channel PFC conversion circuit 1, and can be found in the relevant description of the dual-channel PFC conversion circuit 1 above, which will not be repeated here.

[0182] Accordingly, the PFC conversion circuit 3 may include an inductor L C The two windings T of the autotransformer c1 and T c2 Switch S c1 S c2 S c3 and S c4 diode D c1 D c2 D c3 D c4 D c5 D c6 D c7 and D c8 The specific connections of the circuit components are similar to those of the dual-channel PFC conversion circuit 1, and can be found in the relevant description of the dual-channel PFC conversion circuit 1 above, which will not be repeated here.

[0183] Optionally, in the AC-DC conversion circuit 600, at least some of the diodes mentioned above can be replaced with controllable switching transistors.

[0184] Figure 10 This is a specific example of an AC-DC conversion circuit 700 provided in the embodiments of this application. It should be understood that the AC-DC conversion circuit 700 can be an AC-DC conversion circuit 511 or an AC-DC conversion circuit 512.

[0185] and Figure 8 and Figure 9 The illustrated embodiment is similar in that, Figure 10 In the illustrated embodiment, the AC-DC conversion circuit 700 may also include an input terminal, a three-phase dual-path PFC conversion circuit (i.e., dual-path PFC conversion circuit 1, dual-path PFC conversion circuit 2 and dual-path PFC conversion circuit 3) and a capacitor circuit.

[0186] and Figure 8 and Figure 9 The difference between the illustrated embodiment and the one shown is that, in Figure 10 In the illustrated embodiment, the AC-DC conversion circuit 700 can be a three-phase full-bridge rectifier circuit. Within the AC-DC conversion circuit 700, each dual-path PFC conversion circuit may include an inductor, two windings of an autotransformer, and two switching bridge arms. The capacitor circuit may include capacitors C1 and C2 connected in series.

[0187] Specifically, such as Figure 10As shown, taking a dual-channel PFC conversion circuit 1 as an example, the PFC conversion circuit 1 may include an inductor L A The two windings T of the autotransformer A1 and T A2 Switching bridge arm 1 and switching bridge arm 2. Switching bridge arm 1 includes a switching transistor S connected in series. a1 and switching transistor S a2 The switch bridge arm 2 includes a series-connected switch transistor S. a3 and switching transistor S a4 Inductor L A The left end is connected to the first phase line U, and the inductor L A The right end is connected to the winding T of the autotransformer. A1 and T A2 The left end is connected. The winding T of the autotransformer. A1 The right end can be connected to switch bridge arm 1, and the winding T of the autotransformer A2 The right end can be connected to switch bridge arm 2. Switch bridge arm 1 and switch bridge arm 2 can be connected in parallel between the upper and lower ends of the capacitor circuit.

[0188] Accordingly, the dual-path PFC conversion circuit 2 may include an inductor L B The two windings T of the autotransformer B1 and T B2 Switch S b1 S b2 S b3 and S b4 The specific connections of the circuit components are similar to those of the dual-channel PFC conversion circuit 1, and can be found in the relevant description of the dual-channel PFC conversion circuit 1 above, which will not be repeated here.

[0189] Accordingly, the PFC conversion circuit 3 may include an inductor L C The two windings T of the autotransformer c1 and T c2 Switch S c1 S c2 S c3 and S c4 The specific connections of the circuit components are similar to those of the dual-channel PFC conversion circuit 1, and can be found in the relevant description of the dual-channel PFC conversion circuit 1 above, which will not be repeated here.

[0190] Understandably, based on actual production and design requirements, compared to the three-phase T-type Vienna rectifier circuit and the three-phase I-type Vienna rectifier circuit, the AC-DC converter circuit 700 adopts a three-phase full-bridge rectifier circuit, which has a simpler power topology and can be better suited for scenarios where the switching transistors in the rectifier circuit are high-voltage switching transistors, such as SiC transistors.

[0191] It is understandable that the specific implementation of the AC-DC conversion circuit described above is only illustrative. Depending on actual production and design requirements, other circuit structures may be used for the AC-DC conversion circuit.

[0192] Figure 11 This is a schematic diagram of another charging device 400 provided in an embodiment of this application. It should be understood that... Figure 11 Solid lines in the diagram represent power transmission lines, while dashed lines represent signal transmission lines.

[0193] It should also be understood that Figure 11 The charging device 400 shown includes Figure 4 and Figure 7 Most of the technical features of the charging device 400 shown are described below. Figure 11 and Figure 4 , Figure 7 The differences between them will be described, and the similarities will not be repeated.

[0194] See Figure 11 In some embodiments, the charging device 400 may further include a DC-DC converter 450. The input terminal of the DC-DC converter 450 may be connected to the DC bus 410, and the output terminal of the DC-DC converter 450 may be used for connection to a vehicle. The DC-DC converter 450 may be used to receive a first DC current output from the main power conversion device 420 and the power conversion device 430 through the DC bus 410, and convert the first DC current into a second DC current before outputting it to the vehicle to supply power to the vehicle.

[0195] Specifically, see Figure 11 The main power conversion device 420 may include an AC-DC conversion circuit 421, and the secondary power conversion device 430 may include an AC-DC conversion circuit 43. The AC-DC conversion circuits 421 and 431 are connected in parallel between the external power grid and the DC bus 410, and are used to convert the received AC power into a first DC power, which is then output through the DC bus 410. The DC-DC conversion device 450 can receive the first DC power through the DC bus 410, convert it into a second DC power, and then output it to the vehicle.

[0196] In one possible example, the DC-DC converter 450 can directly receive the first DC power output from the AC-DC converter circuits 421 and 431 via the DC bus 410.

[0197] In another possible example, the charging device 400 may also include an energy storage unit 440. The energy storage unit 440 may be connected to a DC bus 410, and the first DC power output from the AC-DC conversion circuits 421 and 431 may be supplied to the energy storage unit 440 via the DC bus 410. The DC-DC conversion device 450 may receive the first DC power from the energy storage unit 440 via the DC bus 410.

[0198] It is understood that the number of DC-DC conversion devices 450 in the charging device 400 can be one or more. Furthermore, the number of DC-DC conversion devices 450 can be the same as or different from the number of power conversion devices in the charging device 400 (i.e., the sum of the number of main power conversion devices 420 and at least one slave power conversion device 430).

[0199] In some embodiments, continue reading Figure 11 When there are multiple DC-DC converters 450, the charging device 400 may further include a power distribution unit 460. The power distribution unit 460 can be connected between the output terminals of the multiple DC-DC converters 450 and the vehicle. The power distribution unit 460 can be used to dynamically distribute the second DC power output from the multiple DC-DC converters 450 according to the actual charging power required by the vehicle.

[0200] For example, the power distribution unit 460 can use the second DC power output from multiple DC-DC converters 450 to charge a vehicle; or, the power distribution unit 460 can use the second DC power output from multiple DC-DC converters 450 to charge multiple vehicles.

[0201] In some embodiments, continue reading Figure 11 The charging device 400 may further include at least one charging terminal 470. This at least one charging terminal 470 is connected to the output terminal of the DC-DC converter 450. Each of the at least one charging terminal 470 is used to connect to a vehicle, so that the DC-DC converter 450 charges the vehicle connected to that charging terminal 470 through each charging terminal 470.

[0202] It is understood that, in practice, each charging terminal 470 may be connected to at least one DC-DC converter 450 in the charging device 400.

[0203] For details regarding the charging terminal 470, please refer to [link / reference]. Figure 1 and Figure 2 The embodiments shown are not described in detail here.

[0204] This application also provides a charging system, which may include the charging device 400 described above and a vehicle. The charging device 400 can charge the vehicle. For detailed description, please refer to... Figure 1 and Figure 2 The embodiments shown are not described in detail here.

[0205] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A main power conversion device, characterized in that, include: AC-DC converter circuit; A power controller is connected to the AC-DC conversion circuit. The power controller is used to control the AC-DC conversion circuit to receive AC power and convert the AC power into a first DC power before outputting it. A circulating current controller is provided, which sends a synchronization signal to the slave power conversion device via a controller area network (CAN) bus. The synchronization signal is used to synchronize the carrier wave of the slave power conversion device with the carrier wave of the master power conversion device. The circulating current controller includes a first master timer, a first slave timer, and a synchronization timer. The first slave timer is connected to the first master timer, and the synchronization timer is connected to the first master timer and the slave power conversion device. The first master timer is used to adjust the period of the carrier of the master power conversion device to synchronize with the period of the target carrier based on the triggering of the edge of the synchronization signal, wherein the period of the target carrier is synchronized with the period of the carrier of the slave power conversion device; The first master timer is further configured to send a first trigger signal to the first slave timer when the count value of the first master timer is the period value of the target carrier period. The first trigger signal is configured to indicate that the count value of the first slave timer is reset so that the first master timer and the first slave timer are synchronized. The synchronization timer is used to send the synchronization signal to the first master timer and the slave power conversion device when the count value of the synchronization timer is the first period value.

2. The main power conversion device according to claim 1, characterized in that, The main power conversion device also includes a circulating current detection circuit, and the AC-DC conversion circuit includes multiple switches; The circulating current detection circuit is connected to the input terminal of the AC-DC conversion circuit and the circulating current controller; The circulating current detection circuit is used to detect the circulating current value at the input terminal of the AC-DC conversion circuit and transmit the circulating current value to the circulating current controller; The circulating current controller is further configured to receive a first modulation wave from the power controller, adjust the first modulation wave according to the circulating current value to obtain a second modulation wave, the second modulation wave being used to determine a drive signal, the drive signal being used to control the on-time of the plurality of switches.

3. The main power conversion device according to claim 2, characterized in that, The circulating controller is specifically used for: The circulation deviation is determined based on the circulation value and the preset circulation threshold. The circulation deviation is calculated and adjusted to obtain the first compensation amount; The first compensation amount is superimposed on the first modulated wave to obtain the second modulated wave.

4. The main power conversion device according to claim 2 or 3, characterized in that, The circulating current controller is further configured to send the second modulation wave to the power controller; The power controller is further configured to determine the drive signal based on the second modulation wave and the carrier wave of the main power conversion device.

5. A power conversion device, characterized in that, include: AC-DC converter circuit; A power controller is connected to the AC-DC conversion circuit. The power controller is used to control the AC-DC conversion circuit to receive AC power and convert the AC power into a first DC power before outputting it. A circulating current controller is configured to receive a synchronization signal from the primary power conversion device via a controller area network (CAN) bus. This synchronization signal is used to synchronize the carrier wave of the secondary power conversion device with the carrier wave of the primary power conversion device. The circulating controller includes a second master timer and a second slave timer, wherein the second slave timer is connected to the second master timer; The second master timer is used to adjust the period of the carrier of the slave power conversion device to synchronize with the period of the target carrier based on the triggering of the edge of the synchronization signal, wherein the period of the target carrier is synchronized with the period of the carrier of the master power conversion device. The second master timer is further configured to send a second trigger signal to the second slave timer when the count value of the second master timer is the period value of the target carrier period. The second trigger signal is configured to indicate that the count value of the second slave timer is reset so that the second master timer is synchronized with the second slave timer.

6. The power conversion device according to claim 5, characterized in that, The power conversion device further includes a circulating current detection circuit, and the AC-DC conversion circuit includes multiple switches; The circulating current detection circuit is connected to the input terminal of the AC-DC conversion circuit and the circulating current controller; The circulating current detection circuit is used to detect the circulating current value at the input terminal of the AC-DC conversion circuit and transmit the circulating current value to the circulating current controller; The circulating current controller is further configured to receive a first modulation wave from the power controller, adjust the first modulation wave according to the circulating current value to obtain a second modulation wave, the second modulation wave being used to determine a drive signal, the drive signal being used to control the on-time of the plurality of switches.

7. The power conversion device according to claim 6, characterized in that, The circulating controller is specifically used for: The circulation deviation is determined based on the circulation value and the preset circulation threshold. The circulation deviation is calculated and adjusted to obtain the first compensation amount; The first compensation amount is superimposed on the first modulated wave to obtain the second modulated wave.

8. The power conversion device according to claim 6 or 7, characterized in that, The circulating current controller is further configured to send the second modulation wave to the power controller; The power controller is further configured to determine the drive signal based on the second modulation wave and the carrier wave from the power conversion device.

9. A charging device, characterized in that, include: Multiple power conversion devices and DC buses, The plurality of power conversion devices are arranged in parallel, and each of the plurality of power conversion devices includes: AC-DC converter circuit; A power controller is connected to the AC-DC conversion circuit. The power controller is used to control the AC-DC conversion circuit to receive AC power, convert the AC power into a first DC power, and then output it through the DC bus. Circulation controller; The plurality of power conversion devices include a master power conversion device and at least one slave power conversion device, wherein the circulating current controller of the master power conversion device is a master circulating current controller, and the circulating current controller of the slave power conversion device is a slave circulating current controller. The master circulating current controller is used to send a synchronization signal to the slave circulating current controller via a controller area network (CAN) bus. The synchronization signal is used to synchronize the carrier wave of the slave power conversion device with the carrier wave of the master power conversion device. The master circulation controller includes a first master timer, a first slave timer, and a synchronization timer. The slave circulation controller includes a second master timer and a second slave timer. The first slave timer is connected to the first master timer. The synchronization timer is connected to the first master timer and the second master timer. The second slave timer is connected to the second master timer. The first master timer is used to adjust the period of the carrier of the main power conversion device to synchronize with the period of the target carrier based on the triggering of the edge of the synchronization signal; The second master timer is used to adjust the period of the carrier of the slave power conversion device to synchronize with the period of the target carrier based on the triggering of the edge of the synchronization signal; The first master timer is further configured to send a first trigger signal to the first slave timer when the count value of the first master timer is the period value of the target carrier period. The first trigger signal is configured to reset the count value of the first slave timer so as to synchronize the first master timer and the first slave timer. The second master timer is further configured to send a second trigger signal to the second slave timer when the count value of the second master timer is the period value of the target carrier period. The second trigger signal is configured to indicate that the count value of the second slave timer is reset so that the second master timer and the second slave timer are synchronized. The synchronization timer is used to send the synchronization signal to the first master timer and the second master timer when the count value of the synchronization timer is the first period value.

10. The charging device according to claim 9, characterized in that, The power conversion device further includes a circulating current detection circuit, and the AC-DC conversion circuit includes multiple switches; The circulating current detection circuit is connected to the input terminal of the AC-DC conversion circuit and the circulating current controller; The circulating current detection circuit is used to detect the circulating current value at the input terminal of the AC-DC conversion circuit and transmit the circulating current value to the circulating current controller; The circulating current controller is used to receive a first modulation wave from the power controller, adjust the first modulation wave according to the circulating current value to obtain a second modulation wave, the second modulation wave is used to determine a drive signal, and the drive signal is used to control the conduction time of the plurality of switches.

11. The charging device according to claim 10, characterized in that, The circulating controller is specifically used for: The circulation deviation is determined based on the circulation value and the preset circulation threshold. The circulation deviation is calculated and adjusted to obtain the first compensation amount; The first compensation amount is superimposed on the first modulated wave to obtain the second modulated wave.

12. The charging device according to claim 10 or 11, characterized in that, The circulating current controller is further configured to send the second modulation wave to the power controller; The power controller is further configured to determine the drive signal based on the second modulation wave and the carrier wave of the power conversion device.

13. The charging device according to any one of claims 9 to 11, characterized in that, The charging device also includes a DC-DC converter; The input terminal of the DC-DC converter is connected to the DC bus, and the output terminal of the DC-DC converter is used to connect to the vehicle. The DC-DC converter is used to receive the first DC power through the DC bus, convert the first DC power into the second DC power, and output it to the vehicle to charge the vehicle.

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