Direct-to-high-power DC charging system

Abstract

The invention discloses a direct-conversion high-power DC charging system. The phase-shifting transformer module comprises a primary winding and N secondary windings. The rectifier module comprises N / 2 rectifier assemblies. Each rectifier assembly corresponds to two secondary windings. The rectifier assembly comprises two rectifier units. The rectifier unit comprises a rectifier plug-in frame and M AC-DC conversion units. All AC-DC conversion units together constitute a rectifier matrix with N rows and M columns. The rectifier plug-in frame is electrically connected to the corresponding secondary winding. All AC-DC conversion units in the same rectifier unit are arranged in parallel on the rectifier plug-in frame. Two AC-DC conversion units under the same column in the same rectifier assembly are arranged in series to form a rectifier series subcircuit. The rectifier subcircuit is electrically connected to the corresponding charging terminal, or at least two rectifier series subcircuits under the same column are connected in parallel to form a rectifier parallel subcircuit. The rectifier parallel subcircuit is electrically connected to the charging terminal. The invention has a simple structure, a small footprint, and a high power density, and can effectively improve the utilization rate of electric energy and reduce the overall footprint.

Description

Technical Field

[0001] The present invention relates to the technical field of high-power direct current charging, and in particular to a direct-to-high-power direct current charging system. Background Art

[0002] The high-power DC charging system of the existing technology needs to reduce the voltage to AC380V through a low-voltage distribution transformer after the high-voltage mains electricity is introduced, and then redistribute it to the corresponding charging pile rectifier through a low-voltage distribution cabinet. However, the traditional charging pile system has problems such as long distribution path, many equipment, low efficiency, high cost, and large land area. Due to the extremely tight supply of urban land at this stage, the large-scale construction of charging stations will occupy precious land resources, and many cities no longer have large tracts of land for the planning and construction of charging stations. With the continuous rise of new energy industries, electricity efficiency has also become the focus of national attention, and it is urgent to balance the utilization of land and electricity by improving the charging system. Summary of the invention

[0003] The purpose of the present invention is to provide a direct-conversion high-power DC charging system, which has a simple structure, a small footprint, and a high power density, and can effectively improve the utilization rate of electric energy and reduce the overall footprint.

[0004] In order to achieve the above purpose, the present invention discloses a direct-to-high-power DC charging system, which includes a phase-shifting transformer module, a rectifier module and M charging terminals, wherein M is a positive integer, the phase-shifting transformer module includes a primary winding and N secondary windings, wherein N is an even number and N≥2, the primary winding is used to access high-voltage mains, the rectifier module includes N / 2 rectifier components, each of the rectifier components corresponds to two secondary windings, the rectifier component includes two rectifier units, the rectifier unit includes a rectifier frame and M AC-DC conversion units, all A The C-DC conversion units together constitute a rectifier matrix with N rows and M columns, the rectifier frame is electrically connected to the corresponding secondary winding, all AC-DC conversion units in the same rectifier unit are arranged in parallel on the rectifier frame, and the two AC-DC conversion units in the same column of the same rectifier assembly are arranged in series to form a rectifier series sub-circuit, and the rectifier sub-circuit is electrically connected to the corresponding charging terminal, or at least two rectifier series sub-circuits in the same column are connected in parallel to form a rectifier parallel sub-circuit, and the rectifier parallel sub-circuit is electrically connected to the charging terminal.

[0005] Compared with the prior art, the phase-shift transformer module of the present invention includes a primary winding and N secondary windings, wherein N is an even number and N≥2, the primary winding is used to access the high-voltage mains, the rectifier module includes N / 2 rectifier components, each rectifier component corresponds to two secondary windings, the rectifier component includes two rectifier units, the rectifier unit includes a rectifier frame and M AC-DC conversion units, all AC-DC conversion units together constitute a rectifier matrix with N rows and M columns, the rectifier frame is electrically connected to the corresponding secondary winding, all AC-DC conversion units in the same rectifier unit are arranged in parallel on the rectifier frame, and the same rectifier unit The two AC-DC conversion units under the same column in the device are arranged in series to form a rectifying series sub-circuit, and the rectifying sub-circuit is electrically connected to the corresponding charging terminal, or at least two rectifying series sub-circuits under the same column are connected in parallel to form a rectifying parallel sub-circuit, and the rectifying parallel sub-circuit is electrically connected to the charging terminal. It has a simple structure and a small number of components, which can effectively reduce the occupied area, and can flexibly adopt the rectifying series sub-circuit or the rectifying parallel sub-circuit to power the charging terminal according to the number and power requirements of the charging terminals. It has high flexibility and can improve the power supply energy density of the charging terminal through reasonable settings, thereby effectively improving the energy utilization rate.

[0006] Preferably, the direct-conversion high-power DC charging system further includes M fuses, each of which corresponds to one of the charging terminals, and the rectifying series sub-circuit or the rectifying parallel sub-circuit is electrically connected to the corresponding charging terminal through the fuse.

[0007] Preferably, the direct-to-high-power DC charging system further includes M high-voltage DC contactors, each of which corresponds to one of the charging terminals, and the rectifying series sub-circuit or the rectifying parallel sub-circuit is electrically connected to the corresponding charging terminal through the high-voltage DC contactor.

[0008] Preferably, the direct-to-high-power DC charging system further includes N circuit breakers, each of the circuit breakers corresponds to one of the secondary windings, and the secondary winding is electrically connected to the corresponding rectifier frame through the circuit breaker.

[0009] Preferably, the direct-to-high-power DC charging system further includes M control modules, each of which corresponds to one of the charging terminals, and the control module is electrically connected to the corresponding charging module.

[0010] Preferably, the control module is also connected to all AC-DC conversion units of the rectifying series sub-circuit or all AC-DC conversion units of the rectifying parallel sub-circuit electrically connected to the corresponding charging terminal through bus communication.

[0011] Preferably, the direct-conversion high-power DC charging system further includes a high-voltage incoming line cabinet, and the primary winding is connected to the high-voltage mains power through the high-voltage incoming line cabinet.

[0012] Preferably, the high-voltage incoming line cabinet includes a high-voltage load switch, and the primary winding is connected to the high-voltage mains via the high-voltage load switch.

[0013] Preferably, the high-voltage incoming line cabinet also includes a lightning protection device and a secondary signal acquisition device, the lightning protection device is used to prevent lightning from impacting the high-power DC charging system, and the secondary signal acquisition device is used to collect status parameters of the high-voltage mains, high-voltage load switch and / or lightning protection device.

[0014] Preferably, the high voltage mains power is 10KV mains power. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the direct-to-high-power DC charging system of the present invention;

[0016] Figure 2 It is a structural schematic diagram of a phase-shifting transformer module in a direct-conversion high-power DC charging system of the present invention having two secondary windings;

[0017] Figure 3 It is a structural schematic diagram of a phase-shifting transformer module in a direct-conversion high-power DC charging system of the present invention having four secondary windings and a rectifier parallel subcircuit electrically connected to a charging terminal;

[0018] Figure 4 It is a structural schematic diagram of a phase-shifting transformer module in a direct-conversion high-power DC charging system of the present invention having twelve secondary windings and a rectifying parallel subcircuit electrically connected to a corresponding charging terminal. DETAILED DESCRIPTION

[0019] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0020] See also Figure 1-Figure 3 As shown, the direct-conversion high-power DC charging system of this embodiment includes a phase-shifting transformer module 10, a rectifier module and M charging terminals 30, wherein M is a positive integer, and the phase-shifting transformer module 10 includes a primary winding 11 and N secondary windings 12, wherein N is an even number and N ≥ 2, and the primary winding 11 is used to access the high-voltage mains. A temperature detection sensor is configured in each winding core, and an adjustable-speed fan and its control monitoring circuit are configured on the top of the phase-shifting transformer module. Preferably, the high-voltage mains is 10KV mains, and of course, the high-voltage mains can also be high voltages of other volts. It can be understood that after the high-voltage mains is regulated by the phase-shifting transformer module 10, it is converted through N secondary windings 12 to obtain N voltages, and the voltage values ​​of these N voltages can be the same or different.

[0021] The rectifier module includes N / 2 rectifier components, each rectifier component corresponds to two secondary windings 12, the rectifier component includes two rectifier units 20, the rectifier unit 20 includes a rectifier frame and M AC-DC conversion units 21, all AC-DC conversion units 21 together constitute a rectifier matrix with N rows and M columns, the rectifier frame is electrically connected to the corresponding secondary winding 12, all AC-DC conversion units 21 in the same rectifier unit 20 are arranged in parallel on the rectifier frame, two AC-DC conversion units 21 under the same column in the same rectifier component are arranged in series to form a rectifier series sub-circuit, and the rectifier sub-circuit is electrically connected to the corresponding charging terminal 30, or at least two rectifier series sub-circuits under the same column are connected in parallel to form a rectifier parallel sub-circuit, and the rectifier parallel sub-circuit is electrically connected to the charging terminal 30. Figure 1 The schematic diagram of the structure of the direct-conversion high-power DC charging system is shown. Figure 2 The structure diagram of the phase-shift transformer module in the direct-conversion high-power DC charging system having two secondary windings 12 is shown. Figure 3 The schematic diagram shows the structure of the phase-shift transformer module in the high-power DC charging system having four secondary windings 12 and the parallel rectifying sub-circuit electrically connected to the charging terminal 30.

[0022] Preferably, the direct-conversion high-power DC charging system also includes M fuses 40, M high-voltage DC contactors 50 and N circuit breakers 60, each fuse 40 corresponds to a charging terminal 30, and the rectifying series sub-circuit or the rectifying parallel sub-circuit is electrically connected to the corresponding charging terminal 30 through the fuse 40.

[0023] Each high-voltage DC contactor 50 corresponds to a charging terminal 30 , and the rectifying series sub-circuit or the rectifying parallel sub-circuit is electrically connected to the corresponding charging terminal 30 through the high-voltage DC contactor 50 .

[0024] Each circuit breaker 60 corresponds to a secondary winding 12, and the secondary winding 12 is electrically connected to the corresponding rectifier frame through the circuit breaker 60. Through the above configuration, a circuit breaker 60 is configured in front of each rectifier frame to prevent damage to the secondary winding 12 caused by a short circuit of the rectifier module.

[0025] Preferably, the direct-to-high-power DC charging system further includes M control modules 70, each control module 70 corresponds to a charging terminal 30, and the control module 70 is electrically connected to the corresponding charging module. Further, preferably, the control module 70 is also connected to all AC-DC conversion units 21 under the rectifying series subcircuit or rectifying parallel subcircuit electrically connected to the corresponding charging terminal 30 through a bus (such as a CAN bus).

[0026] Preferably, the direct-conversion high-power DC charging system further includes a high-voltage incoming line cabinet 80, and the primary winding 11 is connected to the high-voltage mains through the high-voltage incoming line cabinet 80. Specifically, the high-voltage incoming line cabinet 80 includes a high-voltage load switch, and the primary winding 11 is connected to the high-voltage mains through the high-voltage load switch.

[0027] Preferably, the high-voltage incoming line cabinet 80 also includes a lightning protection device and a secondary signal acquisition device. The lightning protection device is used to prevent lightning from impacting the high-power DC charging system, and the secondary signal acquisition device is used to collect status parameters of the high-voltage AC power, high-voltage load switch and / or lightning protection device.

[0028] See also Figure 1 and Figure 4 As shown, the practical application design of the direct-conversion high-power DC charging system of this embodiment is described in detail below, taking the application in large-scale charging and swapping station equipment as an example. After calculation and measurement, it is found that when the phase-shifting transformer module has twelve secondary windings 12 and the rectifier module includes six rectifier components, it can meet the simultaneous operation of twelve charging terminals 30 to maximize the high-power, high-integration, and high-charging efficiency battery swap concept. Figure 4 The schematic diagram of the structure of the phase-shift transformer module in the direct-conversion high-power DC charging system having four secondary windings 12 and the rectifier parallel sub-circuit electrically connected to the corresponding charging terminal 30 is shown. It should be noted that, in order to simplify the circuit diagram, Figure 4 The connection line between the charging terminal 30 and the corresponding control module 70 is omitted. At this time, the rectifier module has twelve rectifier plug-ins, and the twelve rectifier plug-ins correspond to twelve secondary windings 12 and twelve charging terminals 30 one by one. Six AC-DC conversion units 21 are connected in parallel in each rectifier plug-in frame. For the convenience of description, each secondary winding 12, rectifier plug-in frame and charging terminal 30 are numbered in sequence as 1#, 2#, 3#, ..., 11#, 12#, and the secondary winding 12 and rectifier plug-in frame under the same number correspond one by one.

[0029] Specifically, the phase-shifting transformer module 10 is a phase-shifting transformer with twelve secondary windings 12 outputs. While replacing the power frequency transformer and the low-voltage power distribution link in the traditional charging system, it can also greatly reduce the short-circuit current of the transformer secondary winding 12 and reduce the short-circuit current capacity of its downstream switch. Each secondary winding 12 of the phase-shifting transformer module 10 adopts the extended triangle connection method. Within the range of 360°, due to the difference between each phase shift angle by a certain angle, the number of rectified pulses can be obtained (such as the phase shift angle difference of 5°, the number of rectified pulses is 72). This phase-shifting connection method can effectively eliminate harmonics, make the input current waveform close to a sine wave, and achieve low THD I and high power factor (can reach 99% under optimal working conditions), so that the rectifier module of this embodiment does not need to set the power factor correction link of the traditional module, and its topology is greatly simplified, so that the efficiency of the entire system is significantly improved. The output secondary windings 12 of the phase-shift transformer module 10 are connected to the 1# to 12# rectifier frames respectively. A temperature detection sensor is configured in the core of each secondary winding 12, and a speed-adjustable fan and its control monitoring circuit are configured on the top of the transformer.

[0030] It can be understood that in the direct-conversion high-power DC charging system of this embodiment, the secondary side of the phase-shifting transformer module 10 has a total of twelve secondary windings 12 (the number of secondary windings 12 can be flexibly configured according to engineering requirements), two rectifier devices are configured, each rectifier device is configured with six rectifier frames, and each rectifier frame protects the corresponding secondary winding 12 through a circuit breaker 60.

[0031] In this embodiment, the output voltage of a single rectifier device is 400V and the output power is 30KW. For example, the two AC-DC conversion units 21 in the same column of the 1# rectifier plug-in frame and the 2# rectifier plug-in frame are connected in series to form a rectifier series sub-circuit, the two AC-DC conversion units 21 in the same column of the 3# rectifier plug-in frame and the 4# rectifier plug-in frame are connected in series to form a rectifier series sub-circuit, and the two AC-DC conversion units 21 in the same column of the 5# rectifier plug-in frame and the 6# rectifier plug-in frame are connected in series to form a rectifier series sub-circuit. At this time, the output voltage of each rectifier series sub-circuit is 800V, and then all the rectifier series sub-circuits in the same column are connected in parallel to form a rectifier parallel sub-circuit, so as to finally obtain a 180KW charging bus, that is, the two rectifier devices in this embodiment have a total of twelve 180KW charging buses, and each charging bus is electrically connected to the corresponding charging terminal 30.

[0032] As an extension, this system can also use a single rectifier device with an output voltage of 800V or 1000V. When the output voltage of the single rectifier device is 800V or 1000V, all AC-DC conversion units 21 in the same column are all connected in parallel to form a charging bus. At this time, the use of different secondary windings 12 for parallel output cleverly avoids the influence of the unbalanced output between the secondary windings 12 caused by the different power charged by the charging terminal 30, which causes the harmonics that cannot be completely offset.

[0033] In addition, each charging bus is equipped with a fuse 40, a high-voltage DC contactor 50 and a controller. When a battery is charged, the controller obtains the charging protocol and sends a command through the bus to enable all AC-DC conversion units 21 on the charging bus to quickly charge the battery in constant power mode or constant current mode. When the battery is fully charged, the controller sends a command to disconnect the high-voltage contactor to prevent the battery from being overcharged. Each charging bus corresponds to a separate controller, which enables the system to have a simple and reliable control logic. This case, as a charging device for a large-scale battery swap station, perfectly forms a high-power, high-integration, and high-charging efficiency battery swap concept.

[0034] Combination Figure 1-Figure 4 The phase-shift transformer module of the present invention comprises a primary winding 11 and N secondary windings 12, wherein N is an even number and N≥2, the primary winding 11 is used to access the high-voltage mains, the rectifier module comprises N / 2 rectifier components, each rectifier component corresponds to two secondary windings 12, the rectifier component comprises two rectifier units 20, the rectifier unit 20 comprises a rectifier frame and M AC-DC conversion units 21, all AC-DC conversion units 21 together constitute a rectifier matrix with N rows and M columns, the rectifier frame is electrically connected to the corresponding secondary winding 12, all AC-DC conversion units 21 in the same rectifier unit 20 are arranged in parallel on the rectifier frame, and the same rectifier The two AC-DC conversion units 21 in the same column of the component are arranged in series to form a rectifying series sub-circuit, and the rectifying sub-circuit is electrically connected to the corresponding charging terminal 30, or at least two rectifying series sub-circuits in the same column are connected in parallel to form a rectifying parallel sub-circuit, and the rectifying parallel sub-circuit is electrically connected to the charging terminal 30. It has a simple structure and a small number of components, which can effectively reduce the floor space occupied, and can flexibly use a rectifying series sub-circuit or a rectifying parallel sub-circuit to power the charging terminal 30 according to the number and power requirements of the charging terminals 30. It has high flexibility and can improve the power supply energy density of the charging terminal 30 through reasonable settings, thereby effectively improving the energy utilization rate.

[0035] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A direct-to-high-power DC charging system, characterized in that: The invention comprises a phase-shift transformer module, a rectifier module and M charging terminals, wherein M is a positive integer, the phase-shift transformer module comprises a primary winding and N secondary windings, wherein N is an even number and N≥2, the primary winding is used to access the high-voltage mains, the rectifier module comprises N / 2 rectifier components, each of the rectifier components corresponds to two secondary windings, the rectifier component comprises two rectifier units, the rectifier unit comprises a rectifier frame and m AC-DC conversion units, and all AC-DC conversion units together constitute a circuit having N rows. A rectifier matrix having m columns, wherein the rectifier frame is electrically connected to the corresponding secondary winding, all AC-DC conversion units in the same rectifier unit are arranged in parallel on the rectifier frame, and two AC-DC conversion units in the same column of the same rectifier assembly are arranged in series to form a rectifier series sub-circuit, and the rectifier series sub-circuit is electrically connected to the corresponding charging terminal, or at least two rectifier series sub-circuits in the same column are connected in parallel to form a rectifier parallel sub-circuit, and the rectifier parallel sub-circuit is electrically connected to the charging terminal.

2. The direct-to-high-power DC charging system according to claim 1, characterized in that: It also includes M fuses, each of which corresponds to one of the charging terminals, and the rectifying series sub-circuit or the rectifying parallel sub-circuit is electrically connected to the corresponding charging terminal through the fuse.

3. The high-power direct current charging system according to claim 1, characterized in that: It also includes M high-voltage DC contactors, each of which corresponds to one charging terminal, and the rectifying series sub-circuit or the rectifying parallel sub-circuit is electrically connected to the corresponding charging terminal through the high-voltage DC contactor.

4. The high-power direct current charging system according to claim 1, characterized in that: It also includes N circuit breakers, each of which corresponds to one secondary winding, and the secondary winding is electrically connected to the corresponding rectifier frame through the circuit breaker.

5. The high-power direct current charging system as claimed in claim 1, characterized in that: It also includes M control modules, each of which corresponds to one charging terminal, and the control module is electrically connected to the corresponding charging terminal.

6. The high-power direct current charging system as claimed in claim 5, characterized in that: The control module is also connected to all the AC-DC conversion units of the rectifying series sub-circuit or all the AC-DC conversion units of the rectifying parallel sub-circuit electrically connected to the corresponding charging terminal through bus communication.

7. The high-power direct current charging system as claimed in claim 1, characterized in that: It also includes a high-voltage incoming line cabinet, through which the primary winding is connected to the high-voltage mains.

8. The high-power direct current charging system as claimed in claim 7, characterized in that: The high-voltage incoming line cabinet includes a high-voltage load switch, and the primary winding is connected to the high-voltage mains through the high-voltage load switch.

9. The direct-to-high-power DC charging system according to claim 8, characterized in that: The high-voltage incoming line cabinet also includes a lightning protection device and a secondary signal acquisition device. The lightning protection device is used to prevent lightning from impacting the high-power DC charging system, and the secondary signal acquisition device is used to collect status parameters of the high-voltage mains, high-voltage load switch and / or lightning protection device.

10. The high-power direct current charging system according to claim 1, characterized in that: The high voltage mains power is 10KV mains power.

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