Integrated bidirectional super charging pile based on medium-voltage power supply and implementation method

Abstract

The invention aims to provide an integrated bidirectional super charging pile based on medium-voltage power supply and an implementation method. The system comprises a medium-voltage isolation transformer, a bidirectional inverter, a reactive compensation module and a charging terminal. The primary side of the medium-voltage isolation transformer is connected with a medium-voltage power grid, the medium-voltage isolation transformer comprises a primary winding or a plurality of secondary windings, and the alternating current input end of the bidirectional inverter is connected to the secondary windings of the medium-voltage isolation transformer; the reactive compensation module is connected in parallel with a secondary winding of the medium-voltage isolation transformer, and the capacity required by the reactive compensation module is used for compensating reactive power generated during no-load operation of the medium-voltage isolation transformer; the input of the charging terminal is connected to the DC output of the bidirectional inverter. The system is applied to the technical field of charging pile open source control, and has the advantages that the structure is simple, the requirement of a super charging pile is met, medium voltage can be fully utilized for direct power supply, the overall power utilization efficiency is improved, and cost and noise are reduced.

Description

Technical Field

[0001] The present invention is applied to the technical field of open source control of charging piles, and in particular relates to an integrated bidirectional super charging pile based on medium voltage power supply and an implementation method thereof. Background Art

[0002] With the development of battery technology, the charge and discharge rates that batteries can withstand are getting higher and higher. As a result, bidirectional charging and discharging machines that can both charge and discharge batteries have been born, namely V2G (Vehicle-to-grid). Through V2G, the interaction between electric vehicles and the grid can be realized. When the grid load is low, electric vehicles absorb electricity; when the grid load is high, they release electricity.

[0003] However, the power of super charging piles is relatively large, and the power of a single unit is generally greater than 300kW. When installing on site, the power grid generally needs to be increased. At present, the conventional practice is to add a box transformer on site to convert the medium voltage 10kV or other voltage levels into a low voltage 380V through a transformer to power the super charging pile. The charger generally uses multiple modules of isolated AC / DC in parallel to form a high-power charger, or uses a high-power PCS inverter + multiple isolated DC / DC modules in parallel. The principle block diagram is as follows Figure 5 , Figure 6 As shown, this mode requires two or more conversions due to the isolated AC / DC module or PCS+isolated DC / DC mode, which has low efficiency, high internal module heat generation, and high noise. In actual use, there are problems such as large power loss, high failure rate, and noise nuisance. Therefore, it is necessary to improve the efficiency of super charging piles, reduce noise, and reduce equipment failure rate, and reduce the construction and operation costs of charging stations through a new super charging pile architecture. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an integrated bidirectional super charging pile based on medium voltage power supply and an implementation method thereof, which has a simple structure, meets the requirements of super charging piles, can make full use of medium voltage direct power supply, improve overall power efficiency, reduce costs, and reduce noise.

[0005] The technical solution adopted by the present invention is: the present invention includes a medium-voltage isolation transformer, a bidirectional inverter, a reactive power compensation module, and a charging terminal; the primary side of the medium-voltage isolation transformer is connected to the medium-voltage power grid, the medium-voltage isolation transformer includes a primary winding or several secondary windings, and the AC input end of the bidirectional inverter is connected to the secondary winding of the medium-voltage isolation transformer; the reactive power compensation module is connected in parallel with the secondary winding of the medium-voltage isolation transformer, and the capacity required by the reactive power compensation module is used to compensate for the reactive power generated when the medium-voltage isolation transformer is running at no-load; the input of the charging terminal is connected to the DC output of the bidirectional inverter.

[0006] As can be seen from the above scheme, this application adopts the medium voltage direct supply method to integrate the medium voltage isolation transformer, reactive power compensation module, and bidirectional inverter according to the characteristics of the super charging pile, such as large single-machine power and the general need for grid capacity expansion during on-site implementation, and installs them in a box to achieve high-efficiency, low-cost, and low-noise super charging pile products. Under the same power configuration, compared with the existing technical solutions, this application can improve the overall power efficiency by more than 3% and reduce the cost by about 10%. It also has the characteristics of high charging efficiency, low heat generation of the bidirectional inverter, low noise, low failure rate, low cost of the whole station construction, and can realize the bidirectional charging / discharging function. It can better solve the current problems of high failure rate, high heat generation, high noise, easy dust accumulation after long-term operation, and high cost of the whole station construction.

[0007] A preferred solution is that the medium-voltage isolation transformer includes a two-winding transformer and a three-winding transformer, the two-winding transformer corresponds to a single-gun super charging pile, and the three-winding transformer corresponds to a double-gun super charging pile.

[0008] A preferred solution is that the integrated bidirectional super charging pile based on medium voltage power supply also includes a box, a medium voltage switch cabinet, and a meter cabinet; the interior of the box includes two independent compartments, which are a medium voltage compartment and a low voltage compartment respectively, the medium voltage isolation transformer, the medium voltage switch cabinet, and the meter cabinet are all arranged in the medium voltage compartment, and the reactive power compensation module and the bidirectional inverter are both arranged in the low voltage compartment.

[0009] A preferred solution is that the four walls of the low-pressure chamber are provided with a heat-insulating layer, and the heat-insulating layer has a heat-insulating function.

[0010] A preferred solution is that after the rated voltage of the secondary winding of the medium voltage isolation transformer is converted by the bidirectional inverter, the output DC voltage value should meet the minimum charging DC voltage requirement of the electric vehicle.

[0011] A preferred solution is that the bidirectional inverter is a non-isolated inverter.

[0012] A preferred solution is that the charging terminal is installed at the charging position, and the input end of the charging terminal is connected to the output of the bidirectional inverter through a cable.

[0013] A preferred solution is that the implementation method comprises the following steps: Step 1: The primary side of the medium voltage isolation transformer is connected to the medium voltage power grid, and the medium voltage isolation transformer converts the 10-35KV medium voltage into a low voltage; Step 2: The rated voltage of the secondary winding of the medium voltage isolation transformer is transformed by the bidirectional inverter, and the input of the charging terminal is connected to the DC output of the bidirectional inverter. The output DC voltage value should meet the minimum DC charging voltage requirement of the electric vehicle; Step 3: The reactive power compensation module is connected in parallel with the secondary winding of the medium voltage isolation transformer. The capacity required by the reactive power compensation module is used to compensate for the reactive power generated when the medium voltage isolation transformer is running at no load, thereby improving the power factor of the medium voltage isolation transformer when running at no load to 0.95 or above; Step 4: Install the medium-voltage isolation transformer, the medium-voltage switchgear, the metering cabinet, the reactive power compensation module, and the bidirectional inverter into the interior of the box. The equipment has a good operating environment and is easy to install on site, which solves the current problems of poor operating environment of charging piles, high failure rate, high heat generation, high noise, easy dust accumulation during long-term operation, and high construction cost of the entire station. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a circuit architecture principle block diagram of the single-gun super charging pile; Figure 2 is a schematic diagram of the box layout of the single-gun super charging pile; Figure 3 It is a circuit architecture principle block diagram of the dual-gun super charging pile; Figure 4 It is a circuit architecture principle block diagram of the dual-gun super charging pile; Figure 5 This is a block diagram of the principle of the existing super charging pile using a multi-module isolated AC / DC parallel circuit architecture; Figure 6 This is the principle block diagram of the existing super charging pile using PCS+ multi-module isolated DC / DC parallel circuit architecture. DETAILED DESCRIPTION

[0015] Embodiment 1 like Figure 1 and Figure 2As shown, in this embodiment, the present invention includes a medium-voltage isolation transformer 1, a bidirectional inverter 2, a reactive power compensation module 3, and a charging terminal 4; the primary side of the medium-voltage isolation transformer 1 is connected to the medium-voltage power grid 5, and the medium-voltage isolation transformer 1 includes a primary winding and a secondary winding to form a single-gun super charging pile; the AC input end of the bidirectional inverter 2 is connected to the secondary winding of the medium-voltage isolation transformer 1; the reactive power compensation module 3 is connected in parallel with the secondary winding of the medium-voltage isolation transformer 1, and the capacity required by the reactive power compensation module 3 is used to compensate for the reactive power generated when the medium-voltage isolation transformer 1 is running at no load, thereby meeting the power grid's requirements for power factor and ensuring the normal operation of the charging pile; the input of the charging terminal 4 is connected to the DC output of the bidirectional inverter 2.

[0016] like Figure 1 and Figure 2 As shown, in this embodiment, the integrated bidirectional super charging pile based on medium voltage power supply also includes a box body 6, a medium voltage switch cabinet 7, and a meter cabinet 8; the interior of the box body 6 includes two independent compartments, which are a medium voltage compartment 9 and a low voltage compartment 10, respectively. The medium voltage isolation transformer 1, the medium voltage switch cabinet 7, and the meter cabinet 8 are all arranged in the medium voltage compartment 9, and the reactive power compensation module 3 and the bidirectional inverter 2 are both arranged in the low voltage compartment 10.

[0017] like Figure 1 and Figure 2 As shown, in this embodiment, the four walls of the low-pressure chamber 10 are provided with a heat insulation layer 11, and the heat insulation layer 11 has a heat preservation function.

[0018] like Figure 1 and Figure 2 As shown, in this embodiment, after the rated voltage of the secondary winding of the medium voltage isolation transformer 1 is converted by the bidirectional inverter 2, the output DC voltage value should meet the minimum charging DC voltage requirement of the electric vehicle.

[0019] like Figure 1 and Figure 2 As shown, in this embodiment, the bidirectional inverter 2 is a non-isolated inverter.

[0020] like Figure 1 and Figure 2 As shown, in this embodiment, the charging terminal 4 is installed at the charging position, and the input end of the charging terminal 4 is connected to the output of the bidirectional inverter 2 through a cable.

[0021] Embodiment 2 like Figure 3 and Figure 4As shown, in this embodiment, the present invention includes a medium-voltage isolation transformer 1, two bidirectional inverters 2, two reactive power compensation modules 3, and two charging terminals 4; the primary side of the medium-voltage isolation transformer 1 is connected to the medium-voltage power grid 5, and the medium-voltage isolation transformer 1 includes a primary winding and two secondary windings to form a double-gun super charging pile; the AC input end of the bidirectional inverter 2 is connected to the secondary winding of the medium-voltage isolation transformer 1; the reactive power compensation module 3 is connected in parallel with the secondary winding of the medium-voltage isolation transformer 1, and the capacity required by the reactive power compensation module 3 is used to compensate for the reactive power generated when the medium-voltage isolation transformer 1 is running at no load, thereby meeting the power grid's requirements for power factor and ensuring the normal operation of the charging pile; the input of the charging terminal 4 is connected to the DC output of the bidirectional inverter 2.

[0022] like Figure 3 and Figure 4 As shown, in this embodiment, the integrated bidirectional super charging pile based on medium voltage power supply also includes a box body 6, a medium voltage switch cabinet 7, and a meter cabinet 8; the interior of the box body 6 includes two independent compartments, which are a medium voltage compartment 9 and a low voltage compartment 10, respectively. The medium voltage isolation transformer 1, the medium voltage switch cabinet 7, and the meter cabinet 8 are all arranged in the medium voltage compartment 9, and the two reactive power compensation modules 3 and the two bidirectional inverters 2 are all arranged in the low voltage compartment 10.

[0023] like Figure 3 and Figure 4 As shown, in this embodiment, the four walls of the low-pressure chamber 10 are provided with a heat insulation layer 11, and the heat insulation layer 11 has a heat preservation function.

[0024] like Figure 3 and Figure 4 As shown, in this embodiment, after the rated voltage of the secondary winding of the medium voltage isolation transformer 1 is converted by the bidirectional inverter 2, the output DC voltage value should meet the minimum charging DC voltage requirement of the electric vehicle.

[0025] like Figure 3 and Figure 4 As shown, in this embodiment, the bidirectional inverter 2 is a non-isolated inverter.

[0026] like Figure 3 and Figure 4 As shown, in this embodiment, the two charging terminals 4 are installed at the charging position, and the input ends of the two charging terminals 4 are respectively connected to the outputs of the two bidirectional inverters 2 through cables.

[0027] In this embodiment, the implementation method includes the following steps: Step 1: The primary side of the medium voltage isolation transformer 1 is connected to the medium voltage power grid 5, and the medium voltage isolation transformer 1 converts the 10-35KV medium voltage into a low voltage; Step 2: The rated voltage of the secondary winding of the medium voltage isolation transformer 1 is transformed by the bidirectional inverter 2, and the input of the charging terminal 4 is connected to the DC output of the bidirectional inverter 2. The output DC voltage value should meet the minimum DC charging voltage requirement of the electric vehicle; Step 3: The reactive power compensation module 3 is connected in parallel with the secondary winding of the medium voltage isolation transformer 1. The capacity required by the reactive power compensation module 3 is used to compensate for the reactive power generated when the medium voltage isolation transformer 1 is running at no load, thereby improving the power factor of the medium voltage isolation transformer 1 when running at no load to 0.95 or above; Step 4: Install the medium-voltage isolation transformer 1, the medium-voltage switchgear 7, the metering cabinet 8, the reactive power compensation module 3, and the bidirectional inverter 2 into the interior of the box 6. The equipment has a good operating environment and is easy to install on site, which solves the current problems of poor operating environment of charging piles, high failure rate, high heat generation, high noise, easy dust accumulation during long-term operation, and high construction cost of the entire station. Although the embodiments of the present invention are described with practical solutions, they do not constitute limitations on the meaning of the present invention. For those skilled in the art, it is obvious to modify the implementation scheme and combine it with other solutions based on this description.

Claims

1. An integrated bidirectional super charging pile based on medium voltage power supply, Features: It comprises a medium voltage isolation transformer (1), a bidirectional inverter (2), a reactive power compensation module (3), and a charging terminal (4); the primary side of the medium voltage isolation transformer (1) is connected to a medium voltage power grid (5), the medium voltage isolation transformer (1) comprises a primary winding and a plurality of secondary windings, the AC input end of the bidirectional inverter (2) is connected to the secondary winding of the medium voltage isolation transformer (1); the reactive power compensation module (3) is connected in parallel to the secondary winding of the medium voltage isolation transformer (1), and the capacity required by the reactive power compensation module (3) is used to compensate for the reactive power generated when the medium voltage isolation transformer (1) is running at no load; the input of the charging terminal (4) is connected to the DC output of the bidirectional inverter (2); The integrated bidirectional super charging pile based on medium voltage power supply also includes a box (6), a medium voltage switch cabinet (7), and a meter cabinet (8); the box (6) includes two independent compartments, the two independent compartments are a medium voltage compartment (9) and a low voltage compartment (10), the medium voltage isolation transformer (1), the medium voltage switch cabinet (7), and the meter cabinet (8) are all arranged in the medium voltage compartment (9), and the reactive power compensation module (3) and the bidirectional inverter (2) are all arranged in the low voltage compartment (10).

2. The integrated bidirectional super charging pile based on medium voltage power supply according to claim 1, Features: The medium voltage isolation transformer (1) comprises a two-winding transformer and a three-winding transformer, wherein the two-winding transformer corresponds to a single-gun super charging pile, and the three-winding transformer corresponds to a double-gun super charging pile.

3. The integrated bidirectional super charging pile based on medium voltage power supply according to claim 1, Features: The four walls of the low-pressure chamber (10) are provided with a heat insulation layer (11), and the heat insulation layer (11) has a heat preservation function.

4. The integrated bidirectional super charging pile based on medium voltage power supply according to claim 1, Features: After the rated voltage of the secondary winding of the medium voltage isolation transformer (1) is converted by the bidirectional inverter (2), the output DC voltage value should meet the minimum DC charging voltage requirement of the electric vehicle.

5. The integrated bidirectional super charging pile based on medium voltage power supply according to claim 1, Features: The bidirectional inverter (2) is a non-isolated inverter.

6. The integrated bidirectional super charging pile based on medium voltage power supply according to claim 1, Features: The charging terminal (4) is installed at the charging position, and the input end of the charging terminal (4) is connected to the output of the bidirectional inverter (2) via a cable.

7. A method for implementing the integrated bidirectional super charging pile based on medium voltage power supply as claimed in claim 1, Features: The implementation method includes the following steps: Step 1: The primary side of the medium voltage isolation transformer (1) is connected to the medium voltage power grid (5), and the medium voltage isolation transformer (1) converts the medium voltage of 10 to 35 kV into a low voltage; Step 2: the rated voltage of the secondary winding of the medium voltage isolation transformer (1) is transformed by the bidirectional inverter (2), and the input of the charging terminal (4) is connected to the DC output of the bidirectional inverter (2), and the output DC voltage value should meet the minimum DC charging voltage requirement of the electric vehicle; Step 3: The reactive power compensation module (3) is connected in parallel to the secondary winding of the medium voltage isolation transformer (1), and the capacity required by the reactive power compensation module (3) is used to compensate for the reactive power generated when the medium voltage isolation transformer (1) is running at no load, thereby improving the power factor of the medium voltage isolation transformer (1) when running at no load to 0.95 or above; Step 4: Install the medium voltage isolation transformer (1), the medium voltage switch cabinet (7), the metering cabinet (8), the reactive power compensation module (3), and the bidirectional inverter (2) into the interior of the box (6).

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