Super charging pile for electric vehicle charging

Abstract

The application relates to the field of charging technology and discloses a super charging stack for charging electric vehicles, which comprises a three-phase cascaded H-bridge converter, an isolated DC / DC converter, a power distribution unit and a charging gun. The DC sides of the H-bridge modules of the three-phase cascaded H-bridge converter are connected in one-to-one correspondence with the input ends of the isolated DC / DC converter, the positive and negative output ends of the isolated DC / DC converter are connected in parallel with the switches in the power distribution unit, the other ends of the switches connected with the positive output end are connected with the positive DC bus of the charging gun, and the other ends of the switches connected with the negative output end are connected with the negative DC bus of the charging gun. The application retains the advantages of the three-phase cascaded H-bridge converter having multiple mutually isolated DC bus interfaces, so that simultaneous charging of multiple electric vehicles can be realized, and meanwhile, when electric vehicles with different power demands are simultaneously charged, the in-phase and inter-phase power matching operation of the three-phase cascaded H-bridge converter can be ensured, and the problem of asymmetric or distorted power grid current is improved.

Description

Technical Field

[0001] This invention relates to the field of charging technology, and more particularly to a supercharger stack for charging electric vehicles. Background Technology

[0002] The rapid development of new energy vehicles has made electric vehicle charging technology a key factor influencing technological progress. With the large-scale application of electric vehicles, users' charging needs for temporary, emergency, and long-distance travel are increasing. The problems of difficult and slow charging have not yet been fundamentally solved. In this context, high-power DC fast charging technology and products have demonstrated a crucial supporting role. High-power DC charging equipment, with its advantages of fast charging speed and good stability, will inevitably become a future trend in electric vehicle charging technology.

[0003] The three-phase cascaded H-bridge converter boasts outstanding overall performance, representing an emerging solution for medium-voltage direct-connected high-capacity charging equipment. Firstly, its modular structure allows for system expansion to higher voltage and power levels using low-voltage components, enabling direct connection to the medium-voltage grid without the need for bulky and high-no-load-loss power frequency transformers. Secondly, its multi-level output voltage allows the H-bridge to operate at a lower switching frequency, improving efficiency while achieving high-quality grid-connected current with a smaller LCL filter. Compared to commonly used LCL filters, it offers better system stability under weak grid conditions. Thirdly, the three-phase cascaded H-bridge converter features multiple isolated DC bus interfaces, facilitating simultaneous charging of multiple electric vehicles.

[0004] However, to practically apply three-phase cascaded H-bridge converters to medium-voltage direct-connected high-capacity charging equipment, a typical problem inherent in the three-phase cascaded H-bridge topology must be addressed—power imbalance within and between phases. Power imbalance between phases leads to asymmetrical grid current, failing to meet grid connection criteria; when the power imbalance within a phase reaches a certain level, the load demand will exceed the H-bridge's transmission power capacity, causing overmodulation of higher-power modules, grid current distortion, and even oscillating overcurrent. Therefore, the problem of power imbalance between phases severely restricts the application of three-phase cascaded H-bridge converters in medium-voltage direct-connected high-capacity charging equipment. Summary of the Invention

[0005] This invention addresses the shortcomings and defects of existing technologies by providing a supercharger stack for electric vehicle charging. It retains the advantage of a three-phase cascaded H-bridge converter with multiple isolated DC bus interfaces, enabling simultaneous charging of multiple electric vehicles. Furthermore, when electric vehicles with different power requirements are charged simultaneously, it ensures balanced power operation within and between phases of the three-phase cascaded H-bridge converter, thus improving the problem of grid current asymmetry or distortion.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A supercharger stack for charging electric vehicles includes a three-phase cascaded H-bridge converter, an isolated DC / DC converter, a power distribution unit, and an electric vehicle charging gun.

[0008] A three-phase cascaded H-bridge converter includes an H-bridge module.

[0009] The power distribution unit includes a switch.

[0010] The connection relationship is as follows: the DC side of the H-bridge module of the three-phase cascaded H-bridge converter is connected one-to-one with the input terminal of the isolated DC / DC converter. The positive and negative output terminals of the isolated DC / DC converter are connected in parallel with the switches in the power distribution unit. The other end of the switch connected to the positive output terminal is connected one-to-one with the positive DC bus of the electric vehicle charging gun, and the other end of the switch connected to the negative output terminal is connected one-to-one with the negative DC bus of the electric vehicle charging gun.

[0011] Preferably, the AC side of the three-phase cascaded H-bridge converter used to connect to the medium-voltage distribution network adopts a star connection.

[0012] Preferably, the AC side of the three-phase cascaded H-bridge converter used to connect to the medium-voltage distribution network adopts a delta connection.

[0013] Preferably, the isolated DC / DC converters are all single-input single-output isolated DC / DC converters. In this case, the output terminals of the i-th isolated DC / DC converters of phases A, B, and C are connected in parallel to form port i. Each port has m switches in the power distribution unit connected in parallel at both the positive and negative ends. Each switch is connected to only one end of the positive and negative ends of a port.

[0014] Where m is the number of charging guns for electric vehicles.

[0015] Preferably, the single-input single-output isolated DC / DC converter is a phase-shifted full-bridge converter, an LLC converter, or a DAB converter.

[0016] Preferably, in order to further improve power density and integration, the isolated DC / DC converters all use three-input, one-output isolated DC / DC converters. In this case, the three input terminals of the i-th three-input, one-output isolated DC / DC converter are connected one-to-one to the DC side of the i-th H-bridge module of the cascaded H-bridge converter of phases A, B, and C. The one output terminal of the i-th three-input, one-output isolated DC / DC converter forms port i. Each port has m switches in the power distribution unit connected in parallel at both the positive and negative ends. Each switch is connected to only one end of the positive and negative ends of a port.

[0017] Where m is the number of charging guns for electric vehicles.

[0018] The beneficial technical effects of this invention are as follows: by using a three-phase cascaded H-bridge converter, a direct connection to the medium-voltage power grid can be achieved on the AC side, thereby eliminating the need for a bulky power frequency transformer with high no-load loss; in addition, based on its modular structure, low-voltage devices can be used to achieve high-voltage, high-capacity output, which can meet the needs of ultra-fast charging of electric vehicles.

[0019] By connecting the output ports of the DC / DC converters in the same position among the three phases in parallel, inter-phase power balance is achieved. By controlling different switching combinations through the power distribution unit, intra-phase power balance is achieved. This effectively improves the problem of power imbalance between phases and between phases. When electric vehicles with different power requirements are charging at the same time, the system can also ensure stable operation and meet the grid connection criteria. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall principle of the supercharger stack described in this invention.

[0021] Figure 2 This is the topology of the supercharger stack described in Embodiment 1 of the present invention.

[0022] Figure 3 This is the topology of the supercharger stack described in Embodiment 2 of the present invention.

[0023] Figure 4 The diagram shows the specific connection method between the first phase-shifting full-bridge converter of phases A, B, and C and the H-bridge module in embodiments 1 and 2 of the present invention.

[0024] Figure 5 This is the topology of the supercharger stack described in Embodiment 3 of the present invention.

[0025] Figure 6 This is the topology of the supercharger stack described in Embodiment 4 of the present invention.

[0026] Figure 7 This describes the specific connection method between the three-input, one-output isolated DC / DC converter and the H-bridge module described in embodiments 3 and 4 of the present invention.

[0027] Figure 8 The circuit structure of the power distribution unit described in Embodiments 1 to 4 of the present invention is shown.

[0028] Figure 9 This is a working scenario in Embodiment 1 of the present invention where only one electric vehicle is being charged.

[0029] Figure 10 There are two electric vehicle charging scenarios in Embodiment 1 of the present invention.

[0030] Figure 11This invention provides three working scenarios for electric vehicle charging in Embodiment 1. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and do not limit the scope of the invention.

[0032] Example 1:

[0033] like Figure 1 As shown, a supercharger stack for charging electric vehicles includes a three-phase cascaded H-bridge converter, an isolated DC / DC converter, a power distribution unit, and an electric vehicle charging gun.

[0034] A three-phase cascaded H-bridge converter includes an H-bridge module.

[0035] The power distribution unit includes a switch.

[0036] The connection relationship is as follows: the DC side of the three-phase cascaded H-bridge converter H-bridge module is connected one-to-one with the input terminal of the isolated DC / DC converter. The positive and negative output terminals of the isolated DC / DC converter are respectively connected in parallel with the switches in the power distribution unit. The other end of the switch connected to the positive output terminal is connected one-to-one with the positive DC bus of the electric vehicle charging gun, and the other end of the switch connected to the negative output terminal is connected one-to-one with the negative DC bus of the electric vehicle charging gun. Figure 8 As shown.

[0037] like Figure 2 As shown, the AC side of the three-phase cascaded H-bridge converter used to connect to the medium-voltage distribution network adopts a star connection. In the embodiment, it is assumed that the supercharger is installed and the AC side of the three-phase cascaded H-bridge converter is connected to the 10kV medium-voltage distribution network.

[0038] The isolated DC / DC converters all use single-input single-output isolated DC / DC converters. In this case, the output terminals of the i-th isolated DC / DC converters of phases A, B, and C are connected in parallel to form port i. Each port has m switches in the power distribution unit connected in parallel at both the positive and negative ends. Each switch is connected to only one end of the positive and negative ends of a port.

[0039] The power distribution unit includes 2mn switches.

[0040] Where n is the number of ports and m is the number of electric vehicle charging guns.

[0041] In the embodiment, n = m = 3, and the power distribution unit includes 2mn = 18 switches.

[0042] The single-input, single-output isolated DC / DC converter is a phase-shifted full-bridge converter, an LLC converter, or a DAB converter. In this embodiment, a phase-shifted full-bridge converter is used, such as... Figure 4 As shown.

[0043] like Figure 9 As shown, when only an electric vehicle 1 with a charging power of 120kW is connected to the charging gun 1 for charging, the supercharger stack operates as follows:

[0044] S1: Close the corresponding switch to connect the positive and negative terminals of ports 1, 2, and 3 to charging gun 1, and disconnect the other switches.

[0045] S2, the three-phase cascaded H-bridge converter rectifies the 10kV AC voltage of the medium-voltage distribution network into multiple 200V to 1000V DC voltages, that is, the DC side input voltage of each H-bridge module to the isolated DC / DC converter is 200V to 1000V.

[0046] S3, the constant voltage output power of the isolated DC / DC converter, charges electric vehicle 1. At this time, each of the three ports provides 40kW of power. Since each port is connected in parallel with three single-input single-output isolated DC / DC converters, the output power of each isolated DC / DC converter is (40 / 3)kW. The power provided by the three phases is (40 / 3)+(40 / 3)+(40 / 3)=40kW. It can be seen that the power balance within and between phases of the three-phase cascaded H-bridge converter is achieved.

[0047] like Figure 10 As shown, when an electric vehicle 1 with a charging power of 120kW is connected to charging gun 1 and an electric vehicle 2 with a charging power of 90kW is connected to charging gun 3 for charging, the working process of the supercharger is as follows:

[0048] S1, close the corresponding switch to connect the positive and negative ends of ports 1 and 2 to charging gun 1, close the corresponding switch to connect the positive and negative ends of port 3 to charging gun 3, and disconnect the other switches.

[0049] S2, the three-phase cascaded H-bridge converter rectifies the 10kV AC voltage of the medium-voltage distribution network into multiple 200V to 1000V DC voltages, that is, the DC side input voltage of each H-bridge module to the isolated DC / DC converter is 200V to 1000V.

[0050] S3, the constant voltage output power of the isolated DC / DC converter, charges electric vehicles 1 and 2. At this time, ports 1 and 2 each provide 60kW of power, and port 3 provides 90kW of power. Since each port has three single-input, single-output isolated DC / DC converters connected in parallel, the output power of each isolated DC / DC converter connected to port 1 or 2 is 60 / 3 = 20kW, and the output power of each isolated DC / DC converter connected to port 3 is 90 / 3 = 30kW. The total power provided by the three phases is 20 + 20 + 30 = 70kW. It can be seen that the power imbalance within the phases of the three-phase cascaded H-bridge converter is improved, achieving power balance between phases. Figure 11 As shown, when an electric vehicle 1 with a charging power of 120kW is connected to charging gun 1, an electric vehicle 2 with a charging power of 90kW is connected to charging gun 2, and an electric vehicle 3 with a charging power of 60kW is connected to charging gun 3 for charging, the working process of the supercharger is as follows:

[0051] S1, close the corresponding switch to connect the positive and negative ends of port 1 to charging gun 1, close the corresponding switch to connect the positive and negative ends of port 2 to charging gun 2, close the corresponding switch to connect the positive and negative ends of port 3 to charging gun 3, and disconnect the remaining switches.

[0052] S2, the three-phase cascaded H-bridge converter rectifies the 10kV AC voltage of the medium-voltage distribution network into multiple 200V to 1000V DC voltages, that is, the DC side input voltage of each H-bridge module to the isolated DC / DC converter is 200V to 1000V.

[0053] S3, the constant voltage output power of the isolated DC / DC converter, charges electric vehicles 1, 2, and 3. At this time, port 1 provides 120kW of power, port 2 provides 90kW of power, and port 3 provides 60kW of power. Since each port has three single-input, single-output isolated DC / DC converters connected in parallel, the power output of each isolated DC / DC converter connected to port 1 is 120 / 3 = 40kW, the power output of each isolated DC / DC converter connected to port 2 is 90 / 3 = 30kW, and the power output of each isolated DC / DC converter connected to port 3 is 60 / 3 = 20kW. The power provided by the three phases is 40 + 30 + 20 = 90kW. It can be seen that the problem of power imbalance within the phases of the three-phase cascaded H-bridge converter is improved, and the power balance between the phases of the three-phase cascaded H-bridge converter is achieved.

[0054] Example 2:

[0055] like Figure 1 As shown, a supercharger stack for charging electric vehicles includes a three-phase cascaded H-bridge converter, an isolated DC / DC converter, a power distribution unit, and an electric vehicle charging gun.

[0056] A three-phase cascaded H-bridge converter includes an H-bridge module.

[0057] The power distribution unit includes a switch.

[0058] The connection relationship is as follows: the DC side of the three-phase cascaded H-bridge converter H-bridge module is connected one-to-one with the input terminal of the isolated DC / DC converter. The positive and negative output terminals of the isolated DC / DC converter are respectively connected in parallel with the switches in the power distribution unit. The other end of the switch connected to the positive output terminal is connected one-to-one with the positive DC bus of the electric vehicle charging gun, and the other end of the switch connected to the negative output terminal is connected one-to-one with the negative DC bus of the electric vehicle charging gun. Figure 8 As shown.

[0059] like Figure 3 As shown, the AC side of the three-phase cascaded H-bridge converter used to connect to the medium-voltage distribution network adopts a delta connection. In this embodiment, it is assumed that the supercharger is installed and the AC side of the three-phase cascaded H-bridge converter is connected to the 35kV medium-voltage distribution network.

[0060] The isolated DC / DC converters all use single-input single-output isolated DC / DC converters. In this case, the output terminals of the i-th isolated DC / DC converters of phases A, B, and C are connected in parallel to form port i. Each port has m switches in the power distribution unit connected in parallel at both the positive and negative ends. Each switch is connected to only one end of the positive and negative ends of a port.

[0061] The power distribution unit includes 2mn switches.

[0062] Where n is the number of ports and m is the number of electric vehicle charging guns.

[0063] In the embodiment, n = m = 3, and the power distribution unit includes 2mn = 18 switches.

[0064] The single-input, single-output isolated DC / DC converter is a phase-shifted full-bridge converter, an LLC converter, or a DAB converter. In this embodiment, a phase-shifted full-bridge converter is used, such as... Figure 4 As shown.

[0065] Example 3:

[0066] like Figure 1 As shown, a supercharger stack for charging electric vehicles includes a three-phase cascaded H-bridge converter, an isolated DC / DC converter, a power distribution unit, and an electric vehicle charging gun.

[0067] A three-phase cascaded H-bridge converter includes an H-bridge module.

[0068] The power distribution unit includes a switch.

[0069] The connection relationship is as follows: the DC side of the three-phase cascaded H-bridge converter H-bridge module is connected one-to-one with the input terminal of the isolated DC / DC converter. The positive and negative output terminals of the isolated DC / DC converter are respectively connected in parallel with the switches in the power distribution unit. The other end of the switch connected to the positive output terminal is connected one-to-one with the positive DC bus of the electric vehicle charging gun, and the other end of the switch connected to the negative output terminal is connected one-to-one with the negative DC bus of the electric vehicle charging gun. Figure 8 As shown.

[0070] like Figure 5 As shown, the AC side of the three-phase cascaded H-bridge converter used to connect to the medium-voltage distribution network adopts a star connection. In the embodiment, it is assumed that the supercharger is installed and the AC side of the three-phase cascaded H-bridge converter is connected to the 10kV medium-voltage distribution network.

[0071] To further improve power density and integration, the isolated DC / DC converters all use three-input, one-output isolated DC / DC converters. In this case, the three input terminals of the i-th three-input, one-output isolated DC / DC converter are connected one-to-one to the DC side of the i-th H-bridge module of the cascaded H-bridge converter of phases A, B, and C. The one output terminal of the i-th three-input, one-output isolated DC / DC converter forms port i. Each port has m switches in the power distribution unit connected in parallel at both the positive and negative ends. Each switch is connected to only one end of the positive and negative ends of a port.

[0072] The power distribution unit includes 2mn switches.

[0073] Where n is the number of ports and m is the number of electric vehicle charging guns.

[0074] In the embodiment, n = m = 3, and the power distribution unit includes 2mn = 18 switches.

[0075] like Figure 7 As shown, the three-input, one-output isolated DC / DC converter includes three front-stage DC / AC converter modules, one rear-stage AC / DC converter module, and a high-frequency transformer. The high-frequency transformer couples the front-stage DC / AC converter modules to the rear-stage AC / DC converter module, achieving electrical isolation between the input and output.

[0076] Example 4:

[0077] like Figure 1 As shown, a supercharger stack for charging electric vehicles includes a three-phase cascaded H-bridge converter, an isolated DC / DC converter, a power distribution unit, and an electric vehicle charging gun.

[0078] A three-phase cascaded H-bridge converter includes an H-bridge module.

[0079] The power distribution unit includes a switch.

[0080] The connection relationship is as follows: the DC side of the three-phase cascaded H-bridge converter H-bridge module is connected one-to-one with the input terminal of the isolated DC / DC converter. The positive and negative output terminals of the isolated DC / DC converter are respectively connected in parallel with the switches in the power distribution unit. The other end of the switch connected to the positive output terminal is connected one-to-one with the positive DC bus of the electric vehicle charging gun, and the other end of the switch connected to the negative output terminal is connected one-to-one with the negative DC bus of the electric vehicle charging gun. Figure 8 As shown.

[0081] like Figure 6 As shown, the AC side of the three-phase cascaded H-bridge converter used to connect to the medium-voltage distribution network adopts a delta connection. In this embodiment, it is assumed that the supercharger is installed and the AC side of the three-phase cascaded H-bridge converter is connected to the 35kV medium-voltage distribution network.

[0082] To further improve power density and integration, the isolated DC / DC converters all use three-input, one-output isolated DC / DC converters. In this case, the three input terminals of the i-th three-input, one-output isolated DC / DC converter are connected one-to-one to the DC side of the i-th H-bridge module of the cascaded H-bridge converter of phases A, B, and C. The one output terminal of the i-th three-input, one-output isolated DC / DC converter forms port i. Each port has m switches in the power distribution unit connected in parallel at both the positive and negative ends. Each switch is connected to only one end of the positive and negative ends of a port.

[0083] The power distribution unit includes 2mn switches.

[0084] Where n is the number of ports and m is the number of electric vehicle charging guns.

[0085] In the embodiment, n = m = 3, and the power distribution unit includes 2mn = 18 switches.

[0086] like Figure 7 As shown, the three-input, one-output isolated DC / DC converter includes three front-stage DC / AC converter modules, one rear-stage AC / DC converter module, and a high-frequency transformer. The high-frequency transformer couples the front-stage DC / AC converter modules to the rear-stage AC / DC converter module, achieving electrical isolation between the input and output.

[0087] The above embodiments are descriptions of specific implementations of the present invention, and not limitations thereof. Those skilled in the art can make various modifications and changes without departing from the spirit and scope of the present invention to obtain corresponding equivalent technical solutions. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. A super-charging stack for electric vehicle charging, characterized by, The three-phase cascaded H-bridge converter, the isolated DC / DC converter, the power distribution unit and the electric vehicle charging gun are connected in series. The three-phase cascaded H-bridge converter comprises H-bridge modules. The power distribution unit comprises switches. The connection relationship is that the DC sides of the H-bridge modules of the three-phase cascaded H-bridge converter are connected to the input ends of the isolated DC / DC converters one by one, the positive and negative output ends of the isolated DC / DC converters are connected to the switches in the power distribution unit in parallel, the other ends of the switches connected to the positive output ends are connected to the positive DC bus of the electric vehicle charging gun one by one, and the other ends of the switches connected to the negative output ends are connected to the negative DC bus of the electric vehicle charging gun one by one. The isolated DC / DC converters are all single-input-single-output isolated DC / DC converters, and the output ends of the i-th isolated DC / DC converters of the A-phase, the B-phase and the C-phase are connected in parallel to form port i, the positive and negative ends of each port are connected to m switches in the power distribution unit in parallel, and one switch is connected to one end of the positive and negative ends of one port. m is the number of the electric vehicle charging guns. The parallel connection of the output ports of the DC / DC converters at the same position between the three phases is used to realize the power balance between the phases, and different switch combinations are controlled by the power distribution unit to realize the power balance within the phase.

2. A super-charging stack for charging an electric vehicle as claimed in claim 1, wherein, The AC side of the three-phase cascaded H-bridge converter for connecting the medium-voltage distribution network adopts a star connection mode.

3. A super-charging stack for electric vehicle charging as claimed in claim 1 wherein, The AC side of the three-phase cascaded H-bridge converter for connecting the medium-voltage distribution network adopts a delta connection mode.

4. A super-charging stack for electric vehicle charging as claimed in claim 1 wherein, The single-input-single-output isolated DC / DC converter is a phase-shifted full-bridge converter, an LLC converter or a DAB converter.

5. A super-charging stack for electric vehicle charging as claimed in claim 1 wherein, In order to further improve the power density and integration, the isolated DC / DC converters are all replaced by three-input-one-output isolated DC / DC converters, the three-input ends of the i-th three-input-one-output isolated DC / DC converter are connected to the DC sides of the i-th H-bridge modules of the A-phase, the B-phase and the C-phase cascaded H-bridge converters one by one, one output end of the i-th three-input-one-output isolated DC / DC converter forms port i, the positive and negative ends of each port are connected to m switches in the power distribution unit in parallel, and one switch is connected to one end of the positive and negative ends of one port. m is the number of the electric vehicle charging guns.

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