Direct-current power transmission system and production line

Abstract

The utility model discloses a direct current power transmission system and a production line. The direct-current power transmission system comprises at least one direct-current power transmission loop; the power tracking boost module is connected with the step-down module through a direct current transmission line, the step-down module is further connected with the protection module, the power tracking boost module is further connected with a plurality of photovoltaic modules, and the protection module is connected with a load; the power tracking and boosting module is used for tracking the maximum power point of the photovoltaic module and boosting the output voltage of the photovoltaic module; the step-down module is used for converting the output voltage of the power tracking step-up module into the voltage required by the load; and the protection module is used for preventing reverse current and preventing overcurrent of a direct-current power transmission loop. According to the embodiment of the utility model, the direct current generated by the photovoltaic module is directly supplied to the load, and the direct current is transmitted in an off-grid manner, thereby being beneficial to avoiding limitation of a power grid on direct current transmission, reducing loss of the direct current during transmission, and improving the utilization rate of electric energy.

Description

TECHNICAL FIELD

[0001] The utility model relates to a direct current transmission technical field especially relates to a direct current transmission system and production line. BACKGROUND

[0002] Photovoltaic is a kind of inexhaustible renewable green energy, and photovoltaic power generation system develops rapidly.

[0003] In the prior art, the electric energy generated by the photovoltaic power generation system is often transported and consumed through the power grid. However, the consumption of the electric energy generated by the photovoltaic power generation system by the power grid is limited by the limitation of the power grid architecture, and the electric energy generated by the photovoltaic power generation system has high loss during transportation and consumption, and the electric energy utilization rate is low. SUMMARY

[0004] The utility model provides a kind of direct current transmission system and production line to avoid the limitation of power grid to direct current transmission, reduce the loss of direct current during transportation, improve electric energy utilization rate.

[0005] According to an aspect of the utility model, a direct current transmission system is provided, which comprises at least one direct current transmission loop.

[0006] The direct current transmission loop comprises a power tracking and boosting module, a direct current transmission line, a voltage reduction module and a protection module. The power tracking and boosting module is connected to the voltage reduction module through the direct current transmission line. The voltage reduction module is also connected to the protection module. The power tracking and boosting module is also connected to multiple photovoltaic modules. The protection module is connected to a load.

[0007] The power tracking and boosting module is used to track the maximum power point of the photovoltaic module and boost the output voltage of the photovoltaic module. The voltage reduction module is used to convert the output voltage of the power tracking and boosting module into the voltage required by the load. The protection module is used to prevent reverse current and prevent overcurrent of the direct current transmission loop.

[0008] Optionally, the power tracking and boosting module comprises a power tracking unit and a boosting unit.

[0009] The power tracking unit is connected to the photovoltaic module. The power tracking unit is also connected to the boosting unit. The boosting unit is connected to the photovoltaic module. The boosting unit is also connected to the voltage reduction module through the direct current transmission line.

[0010] The power tracking unit is used to track the maximum power point of the photovoltaic module. The boosting unit is used to boost the output voltage of the photovoltaic module.

[0011] Optionally, the voltage boosting unit comprises a voltage boosting controller and a voltage boosting chopper circuit.

[0012] The voltage boosting controller is connected with the power tracking unit, and is also connected with the voltage boosting chopper circuit; the voltage boosting chopper circuit is also connected with the photovoltaic module, and is also connected with the voltage dropping module through the DC transmission circuit.

[0013] The voltage boosting controller is configured to drive the voltage boosting chopper circuit according to the maximum output power of the photovoltaic module; and the voltage boosting chopper circuit is configured to boost the output voltage of the photovoltaic module.

[0014] Optionally, the protection module comprises a reverse unit and an overcurrent protection unit.

[0015] The reverse unit and the overcurrent protection unit are connected in series; the reverse unit is also connected with the voltage dropping module, and the overcurrent protection unit is also connected with the load.

[0016] The reverse unit is configured to prevent reverse current; and the overcurrent protection unit is configured to prevent overcurrent of the DC transmission circuit.

[0017] Optionally, the protection module further comprises a filter unit, a lightning protection unit and a temperature detection unit.

[0018] The filter unit is connected with the reverse unit, and is also connected with the lightning protection unit; the lightning protection unit is also connected with the load; and the temperature detection unit is connected with the filter unit, the reverse unit, the power tracking and voltage boosting module and the voltage dropping module respectively.

[0019] The filter unit is configured to filter high-frequency voltage in the DC power; the lightning protection unit is configured to discharge surge voltage; the temperature detection unit is configured to detect the temperature of the reverse unit and the filter unit, and generate a detection signal when the temperature of the reverse unit is greater than a first preset temperature and / or the temperature of the filter unit is greater than a second preset temperature; and the power tracking and voltage boosting module and the voltage dropping module are also configured to stop running according to the detection signal.

[0020] Optionally, the reverse unit comprises a reverse diode.

[0021] Optionally, the overcurrent protection unit comprises a fuse.

[0022] Optionally, the voltage dropping module comprises a voltage dropping controller and a voltage dropping conversion circuit.

[0023] The voltage reduction controller is connected with the voltage reduction conversion circuit, the voltage reduction conversion circuit is also connected with the power tracking voltage increase module through the direct current transmission line, and the voltage reduction conversion circuit is also connected with the protection module.

[0024] The voltage reduction controller is used for driving the voltage reduction conversion circuit, and the voltage reduction conversion circuit is used for converting the output voltage of the power tracking voltage increase module into the voltage required by the load.

[0025] Optionally, the direct current transmission loop further comprises at least one busbar box.

[0026] The busbar box is connected between the photovoltaic module and the power tracking voltage increase module.

[0027] The busbar box is used for collecting the output current of a plurality of photovoltaic modules.

[0028] According to another aspect of the utility model, a production line is further provided, and the production line comprises the direct current transmission system according to any one of the above embodiments.

[0029] The utility model embodiment tracks the maximum output power point of photovoltaic module through power tracking voltage increase module, makes photovoltaic module realize maximum power output, and boosts the output electric energy of photovoltaic module. The output voltage of power tracking voltage increase module is acquired by the voltage reduction module, and the output voltage of power tracking voltage increase module is reduced, and is delivered to the load through the protection module. The direct current generated by the photovoltaic module is directly supplied to the load in the utility model embodiment, and the direct current is delivered off-grid, which is beneficial to avoid the limitation of power grid on direct current transmission, reduce the loss of direct current during transmission, and improve the electric energy utilization rate.

[0030] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the utility model, and is not used to limit the scope of the utility model. Other features of the utility model will become easy to understand through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed to be used in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0032] Figure 1 It is a schematic diagram of a direct current transmission system provided by the utility model embodiment;

[0033] Figure 2It is another schematic diagram of a direct current transmission system provided by the embodiment of the utility model;

[0034] Figure 3 It is another schematic diagram of a direct current transmission system provided by the embodiment of the utility model;

[0035] Figure 4 It is another schematic diagram of a direct current transmission system provided by the embodiment of the utility model;

[0036] Figure 5 It is another schematic diagram of a direct current transmission system provided by the embodiment of the utility model;

[0037] Figure 6 It is another schematic diagram of a direct current transmission system provided by the embodiment of the utility model;

[0038] Figure 7 It is a schematic diagram of a production line provided by the embodiment of the utility model. Specific implementation

[0039] In order to make the person skilled in the art better understand the utility model scheme, the technical scheme in the embodiment of the utility model will be described clearly and completely below in conjunction with the drawings in the embodiment of the utility model, obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor should belong to the scope of protection of the utility model.

[0040] It should be noted that the terms "first", "second" and the like in the description and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0041] The embodiment of the utility model provides a kind of direct current transmission system.The direct current transmission system is applied to production line, direct current generated by photovoltaic module is directly supplied to production line, direct current carries out off-grid delivery, it is favorable to avoid the limitation of power grid to direct current delivery, reduce the loss of direct current when delivering, improve power utilization rate. Figure 1It is a schematic diagram of a direct current transmission system provided by the embodiment of the utility model. Refer to Figure 1 The direct current transmission system comprises at least one direct current transmission loop 100.

[0042] The direct current transmission loop 100 comprises a power tracking boost module 110, a step-down module 120, a protection module 130 and a direct current transmission line 140; the power tracking boost module 110 is connected with the step-down module 120 through the direct current transmission line 140, the step-down module 130 is also connected with the protection module 130, the power tracking boost module 110 is also connected with a plurality of photovoltaic components 10, and the protection module 130 is connected with a load 20. The power tracking boost module 110 is used for tracking the maximum power point of the photovoltaic component 10 and boosting the output voltage of the photovoltaic component 10; the step-down module 120 is used for converting the output voltage of the power tracking boost module 110 into the voltage required by the load 20; and the protection module 130 is used for preventing reverse current and preventing overcurrent of the direct current transmission loop.

[0043] Specifically, the power tracking boost module 110 samples the current and voltage output by the photovoltaic component 10 and obtains the maximum power point of the photovoltaic component 10 according to the sampling result. The power tracking boost module 110 adjusts the impedance of itself according to the obtained maximum power point of the photovoltaic component 10, so that the impedance of the power tracking boost module 110 matches the impedance of the photovoltaic component 10, and then the photovoltaic component 10 realizes maximum power output. The power tracking boost module 110 also boosts the output voltage of the photovoltaic component 10. The boosted direct current is transmitted through the direct current transmission line 140. Exemplarily, the direct current transmission level of the direct current transmission line 140 can be 20 kilovolts. It should be noted that the current of the boosted direct current is low, which is conducive to reducing the power loss in the transmission process.

[0044] The step-down module 120 obtains the power in the direct current transmission line 140 and steps down the power in the direct current transmission line 140, and the voltage level of the stepped-down power matches the voltage required by the load 20. The power output by the step-down module 120 is output to the load 20 through the protection module 130 to drive the load 20 to operate. It should be noted that the direct current transmission line 140 between the power tracking boost module 110 and the step-down module 120 can be overhead laid, can be buried laid, or can be laid in a combination of overhead and buried, and in actual application, the direct current transmission line 140 can be laid according to actual needs, and the embodiment does not limit this.

[0045] The protection module 130 limits the current direction and current size of the power output by the step-down module 120 to prevent the current of the load 20 from flowing back when the direct current transmission loop appears a short circuit fault and to prevent the current of the direct current transmission loop from overcurrent.

[0046] The utility model embodiment tracks the maximum output power point of photovoltaic module 10 through power tracking boost module 110, makes photovoltaic module 10 realize maximum power output, and boosts the output electric energy of photovoltaic module 10. The output voltage of power tracking boost module 110 is acquired by step-down module 120, and the output voltage of power tracking boost module 110 is stepped down, and is delivered to load 20 through protection module 130. The utility model embodiment directly supplies the direct current generated by photovoltaic module 10 to load 20, and the direct current is delivered off-grid, which is conducive to avoiding the limitation of power grid on direct current delivery, reducing the loss of direct current during delivery, and improving the power utilization rate.

[0047] Figure 2 It is another schematic diagram of the direct current transmission system provided by the utility model embodiment. On the basis of the above embodiment, optionally, referring to Figure 2 , power tracking boost module 110 includes: power tracking unit 111 and boost unit 112.

[0048] Power tracking unit 111 is connected with photovoltaic module 10, and power tracking unit 111 is also connected with boost unit 112, boost unit 112 is connected with photovoltaic module 10, and boost unit 112 is also connected with step-down module 120 through direct current transmission line 140; power tracking unit 110 is used to track the maximum power point of photovoltaic module 10; boost unit 112 is used to boost the output voltage of photovoltaic module 10.

[0049] Specifically, power tracking unit 111 samples the current and voltage output by photovoltaic module 10, and obtains the maximum power point of photovoltaic module 10 according to the sampling result. Boost unit 112 obtains the maximum power point of photovoltaic module 10, and adjusts the impedance of itself according to the obtained maximum power point of photovoltaic module 10, so that the impedance of boost unit 112 matches the impedance of photovoltaic module 10, and then the maximum power output of photovoltaic module 10 is realized. Boost unit 112 also boosts the output voltage of photovoltaic module 10. It should be noted that photovoltaic module 10 and boost unit 112 can be considered as linear circuits in a short time, therefore, when the impedance of boost unit 112 matches the impedance of photovoltaic module, the maximum power output of photovoltaic module 10 can be realized.

[0050] Figure 3 It is another schematic diagram of the direct current transmission system provided by the utility model embodiment. On the basis of the above embodiment, optionally, referring to Figure 3 , boost unit 112 includes: boost controller 1121 and boost chopper circuit 1122.

[0051] The boost controller 1121 is connected with the power tracking unit 111, and is also connected with the boost chopper circuit 1122; the boost chopper circuit 1122 is also connected with the photovoltaic module 10, and is also connected with the voltage reduction module 120 through the direct current transmission line 140; the boost controller 1121 is used for driving the boost chopper circuit 1122 according to the maximum output power of the photovoltaic module 10; and the boost chopper circuit 1122 is used for boosting the output voltage of the photovoltaic module 10.

[0052] Specifically, the boost controller 1121 obtains the maximum power point of the photovoltaic module 10, and generates a driving signal according to the obtained maximum power point of the photovoltaic module 10. Wherein, the boost controller 1121 adjusts the duty cycle of the generated driving signal according to the maximum power point of the photovoltaic module 10. The impedance of the boost chopper circuit 1122 is related to the duty cycle of the driving signal, and when the duty cycle of the driving signal changes, the impedance of the boost chopper circuit 1122 also changes. The boost controller 1121 adjusts the impedance of the boost chopper circuit 1122 by adjusting the duty cycle of the generated driving signal, so that the impedance of the boost chopper circuit 1122 matches the impedance of the photovoltaic module 10, and then the photovoltaic module 10 realizes the maximum power output. In addition, the boost chopper circuit 1122 also boosts the output voltage of the photovoltaic module 10. It should be noted that the boost ratio of the boost chopper circuit 1122 can be set according to actual needs, and the embodiment does not limit this.

[0053] Figure 4 is a schematic diagram of another direct current transmission system provided by the embodiment of the utility model. On the basis of each of the above embodiments, optionally, referring to Figure 4 The protection module 130 comprises an inversion unit 131 and an overcurrent protection unit 132.

[0054] The inversion unit 131 and the overcurrent protection unit 132 are connected in series; the inversion unit 131 is also connected with the voltage reduction module 120, and the overcurrent protection unit 132 is also connected with the load 20; the inversion unit 131 is used for preventing reverse current; and the overcurrent protection unit 132 is used for preventing overcurrent of the direct current transmission loop 100.

[0055] Specifically, the reverse unit 131 and the overcurrent protection unit 132 are connected in series between the step-down module 120 and the load 20. The reverse unit 131 limits the current direction in the DC power transmission loop 100 to ensure that the current direction in the DC power transmission loop 100 is always from the step-down module 120 to the load 20, thereby avoiding reverse current in the DC power transmission loop 100. The overcurrent protection unit 132 limits the current size of the DC power transmission loop 100, and when the DC power transmission loop 100 is greater than the maximum allowable current of the overcurrent protection unit 132, the overcurrent protection unit 132 cuts off the loop between the DC power transmission loop 100 and the load 20, thereby avoiding overcurrent of the DC power transmission loop 100. It should be noted that the maximum allowable current of the overcurrent protection unit 132 can be set according to actual needs, and the present embodiment does not limit this. Exemplarily, the overcurrent protection unit 132 can include a fuse; the reverse unit 131 can include a reverse diode, and the number of reverse diodes in the reverse unit 131 is at least one. The reverse diode can be arranged on the connection loop between the positive electrode of the load 20 and the reverse unit 131, or on the negative electrode loop between the load 20 and the reverse unit 131, or on both loops, and the present embodiment does not limit this.

[0056] On the basis of the above-mentioned embodiments, optionally, continuing to refer to Figure 4 The protection module 130 further comprises a filter unit 133, a lightning protection unit 134, and a temperature detection unit 135.

[0057] The filter unit 133 is connected with the reverse unit 131, the filter unit 133 is further connected with the lightning protection unit 134, the lightning protection unit 134 is further connected with the load 20, and the temperature detection unit 135 is connected with the filter unit 133, the reverse unit 131, the power tracking boost module 110, and the step-down module 120, respectively. The filter unit 133 is used for filtering high-frequency voltage in the DC power; the lightning protection unit 134 is used for discharging surge voltage; the temperature detection unit 135 is used for detecting the temperature of the reverse unit 131 and the filter unit 133, and generating a detection signal when the temperature of the reverse unit 131 is greater than a first preset temperature and / or the temperature of the filter unit 133 is greater than a second preset temperature; the power tracking boost module 110 and the step-down module 120 are further used for stopping operation according to the detection signal.

[0058] Specifically, the filter unit 133 and the lightning protection unit 134 are connected in series between the overcurrent protection unit 132 and the load 20. The filter unit 133 filters high-frequency voltage in the direct current output by the step-down module 120. The lightning protection unit 134 discharges surge current in the direct current output by the step-down module 120 to prevent the surge caused by lightning from impacting the load 20. The temperature detection unit 135 detects the temperature of the inversion unit 131 and the temperature of the filter unit 133, and generates a detection signal when the temperature of the inversion unit 131 is greater than a first preset temperature and / or the temperature of the filter unit 133 is greater than a second preset temperature. The power tracking boost module 110 and the step-down module 120 obtain the detection signal and are locked according to the detection signal. The power tracking boost module 110 and the step-down module 120 stop the current conversion when locked to avoid over-temperature of the inversion unit 131 and / or the filter unit 133. It should be noted that the first preset temperature is a maximum allowable temperature of the inversion unit 131 preset in advance, and the second preset temperature is a maximum allowable temperature of the filter unit 133 preset in advance. In actual application, the first preset temperature and the second preset temperature can be set according to actual needs, and the embodiment does not limit this. Illustratively, the filter unit 133 can include an electromagnetic interference filter; and the lightning protection unit 134 can include a surge protector.

[0059] Figure 5 is a schematic diagram of another direct current transmission system provided by the embodiment of the utility model. On the basis of each of the above embodiments, optionally, referring to Figure 5 , the step-down module 120 includes: a step-down controller 121 and a step-down conversion circuit 122.

[0060] The step-down controller 121 is connected with the step-down conversion circuit 122, the step-down conversion circuit 122 is further connected with the power tracking boost module 110 through the direct current transmission line 140, and the step-down conversion circuit 122 is further connected with the protection module 130; the step-down controller 121 is used to drive the step-down conversion circuit 122; and the step-down conversion circuit 122 is used to convert the output voltage of the power tracking boost module 110 into the voltage required by the load 20.

[0061] Figure 6 is a schematic diagram of another direct current transmission system provided by the embodiment of the utility model. On the basis of each of the above embodiments, optionally, referring to Figure 6 , the direct current transmission circuit 100 further includes: at least one bus box 150.

[0062] The confluence box 150 is connected between the photovoltaic module 10 and the power tracking boost module 110; the confluence box 150 is used for collecting the output current of the plurality of photovoltaic modules 10.

[0063] The utility model embodiment further provides a production line. Figure 7 It is a schematic diagram of the production line provided by the utility model embodiment. Figure 7 The production line 1000 comprises the direct current transmission system 2000 provided by any of the above embodiments.

[0064] The production line 1000 provided by the embodiment has the beneficial effects of the direct current transmission system 2000 provided by any of the above embodiments, which will not be repeated here.

[0065] It should be understood that the various forms of the flow shown above can be used to reorder, add or delete steps. For example, the steps described in the utility model can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the utility model can be achieved, which is not limited herein.

[0066] The above specific embodiments do not constitute a limitation on the scope of protection of the utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement within the spirit and principles of the utility model should be included in the scope of protection of the utility model.

Claims

1. A direct current power transmission system, characterized in that The application relates to a direct-current transmission circuit. The direct-current transmission circuit comprises a power tracking and boosting module, a direct-current transmission line, a voltage reducing module and a protection module; the power tracking and boosting module is connected with the voltage reducing module through the direct-current transmission line; the voltage reducing module is further connected with the protection module; the power tracking and boosting module is further connected with a plurality of photovoltaic components; the protection module is connected with a load; The power tracking and boosting module is used for tracking a maximum power point of the photovoltaic component and boosting an output voltage of the photovoltaic component; the voltage reducing module is used for converting the output voltage of the power tracking and boosting module into a required voltage of the load; and the protection module is used for preventing reverse current and overcurrent of the direct-current transmission circuit. The power tracking and boosting module comprises a power tracking unit and a boosting unit.

2. The direct current power transmission system of claim 1, wherein, The power tracking unit is connected with the photovoltaic component and the boosting unit; the boosting unit is connected with the photovoltaic component and the voltage reducing module through the direct-current transmission line. The power tracking unit is used for tracking the maximum power point of the photovoltaic component; and the boosting unit is used for boosting the output voltage of the photovoltaic component. The boosting unit comprises a boosting controller and a boosting chopper circuit.

3. The direct current power transmission system of claim 2, wherein, The boosting controller is connected with the power tracking unit and the boosting chopper circuit; the boosting chopper circuit is further connected with the photovoltaic component and the voltage reducing module through the direct-current transmission line. The boosting controller is used for driving the boosting chopper circuit according to the maximum output power of the photovoltaic component; and the boosting chopper circuit is used for boosting the output voltage of the photovoltaic component. The protection module comprises a reverse prevention unit and an overcurrent protection unit.

4. The direct current power transmission system of claim 1, wherein The reverse prevention unit and the overcurrent protection unit are connected in series; the reverse prevention unit is further connected with the voltage reducing module; and the overcurrent protection unit is further connected with the load. The reverse prevention unit is used for preventing reverse current; and the overcurrent protection unit is used for preventing overcurrent of the direct-current transmission circuit. The protection module further comprises a filter unit, a lightning protection unit and a temperature detection unit.

5. The direct current power transmission system of claim 4, wherein, The filter unit is connected with the reverse prevention unit and the lightning protection unit; the lightning protection unit is further connected with the load; and the temperature detection unit is connected with the filter unit, the reverse prevention unit, the power tracking and boosting module and the voltage reducing module respectively. The filter unit is used for filtering high-frequency voltage in direct current; the lightning protection unit is used for discharging surge voltage; the temperature detection unit is used for detecting temperatures of the reverse prevention unit and the filter unit and generating a detection signal when the temperature of the reverse prevention unit is greater than a first preset temperature and / or the temperature of the filter unit is greater than a second preset temperature; and the power tracking and boosting module and the voltage reducing module are further used for stopping operation according to the detection signal. The reverse prevention unit comprises a reverse prevention diode.

6. The direct current power transmission system of claim 4, wherein, The overcurrent protection unit comprises a fuse.

7. The direct current power transmission system of claim 4, wherein, The voltage reducing module comprises a voltage reducing controller and a voltage reducing conversion circuit.

8. The direct current power transmission system of claim 1, wherein, ​ The voltage reduction controller is connected with the voltage reduction conversion circuit, the voltage reduction conversion circuit is further connected with the power tracking voltage increasing module through the direct current transmission line, and the voltage reduction conversion circuit is further connected with the protection module. The voltage reduction controller is used to drive the voltage reduction conversion circuit, and the voltage reduction conversion circuit is used to convert the output voltage of the power tracking voltage increasing module into the voltage required by the load.

9. The direct current power transmission system of claim 1, wherein, The direct current transmission loop further comprises at least one busbar box. The busbar box is connected between the photovoltaic module and the power tracking voltage increasing module. The busbar box is used to collect the output current of a plurality of photovoltaic modules.

10. A production line, characterized in that, The direct current transmission system comprises the busbar box according to any one of claims 1-9.

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