DC multi-microgrid system and control method

Abstract

The present application provides a DC multi-microgrid system and a control method, including a total energy router, a plurality of sub-center energy routers and a plurality of household-level routers. The total energy router is used to convert three-phase alternating current and / or single-phase alternating current into a first direct current and a second direct current, and output three-phase alternating current, single-phase alternating current, a first direct current and a second direct current. Each sub-center energy router is electrically connected to the total energy router. The sub-center energy router is provided with a plurality of groups of output interfaces for outputting three-phase alternating current or single-phase alternating current, a first direct current and a second direct current. Each household-level router is electrically connected to a group of output interfaces. The control device in the household-level router controls the photovoltaic power generation device, the energy storage device, the three-phase alternating current or single-phase alternating current, the first direct current and the second direct current to bid and output according to preset rules so that the load can operate normally. The sub-center energy router is also used to coordinate the flow of electric energy between each household-level router.

Description

Technical Field

[0001] The present application relates to the field of microgrid technology, and in particular to a DC multi-microgrid system and a control method. Background Art

[0002] In microgrids, AC microgrid applications are currently the main focus. The energy system of the microgrid is established through photovoltaics, energy storage, diesel generators, etc. The system realizes AC power supply through inverters. Compared with the AC system, the DC system has a relatively large advantage. It does not need to consider frequency, phase and other controls. At the same time, through DC direct drive, the system efficiency is effectively improved.

[0003] The current public scheme for DC microgrids mainly establishes DC through high-voltage busbars and realizes power supply guarantee of the system itself through two ring networks. However, this method makes the system itself have problems such as redundancy and uneconomical. Summary of the invention

[0004] Based on this, it is necessary to provide a DC multi-microgrid system and control method to address the problems of redundancy and uneconomical nature of the existing DC microgrid system, which establishes DC through a high-voltage bus and realizes power supply guarantee of the system itself through two ring networks.

[0005] A direct current multi-microgrid system, comprising:

[0006] A total energy router, wherein the input end of the total energy router is used to obtain three-phase alternating current and single-phase alternating current respectively, and the total energy router is used to convert the three-phase alternating current and / or the single-phase alternating current into a first direct current and a second direct current, and output the three-phase alternating current, the single-phase alternating current, the first direct current and the second direct current;

[0007] A plurality of sub-center energy routers, each of which is electrically connected to the output end of the main energy router, and the sub-center energy routers are provided with a plurality of groups of output interfaces, each group of the output interfaces is used to output the three-phase alternating current or the single-phase alternating current, the first direct current and the second direct current; and

[0008] A plurality of household-level routers, each of which is electrically connected to a group of the output interfaces, the output end of the household-level router is used to electrically connect to a load, and the household-level router is used to obtain the three-phase alternating current or the single-phase alternating current, the first direct current, and the second direct current;

[0009] The household router includes a control device, a photovoltaic power generation device, and an energy storage device. The control device controls the photovoltaic power generation device, the energy storage device, the three-phase alternating current or the single-phase alternating current, the first direct current, and the second direct current to bid and output according to preset rules so that the load can operate normally;

[0010] The sub-center energy router is also used to coordinate the flow of power between the household-level routers.

[0011] In one of the embodiments, the control device is configured to preferentially control the photovoltaic power generation device and / or the energy storage device to supply power to the load, and determine whether the power supply of the photovoltaic power generation device and the energy storage device meets the power demand of the load;

[0012] If it is determined that the power supply of the photovoltaic power generation device and the energy storage device does not meet the power demand of the load, the control device controls the three-phase AC power or the single-phase AC power, the first DC power and the second DC power to competitively output so that the load can operate normally.

[0013] In one embodiment, the source of the first direct current received by the household router is the first direct current directly output by the sub-center energy router or the first direct current output by other household routers;

[0014] The source of the second direct current received by the household-level router is the second direct current directly output by the sub-center energy router or the second direct current output by other household-level routers.

[0015] In one of the embodiments, the control device is electrically connected to the photovoltaic power generation device, the energy storage device and the sub-center energy router respectively, and the control device is also used to obtain the remaining power of the energy storage device and determine whether to control the energy storage device to discharge based on a power setting threshold.

[0016] In one embodiment, the control device is used to compare the remaining power with the power setting threshold. If the remaining power is greater than the power setting threshold, the control device controls the energy storage device to discharge. If the remaining power is less than or equal to the power setting threshold, the control device controls the energy storage device not to discharge.

[0017] In one embodiment, the output interface includes an AC output interface, a first DC output interface, and a second DC output interface. The AC output interface, the first DC output interface, and the second DC output interface are all provided with switching devices, and each of the switching devices is used to control the conduction and disconnection of the AC output interface, the first DC output interface, or the second DC output interface.

[0018] In one embodiment, the sub-center energy router includes:

[0019] The sub-center control device is electrically connected to the plurality of switch devices and the plurality of control devices respectively, and is used to control the on and off of each of the switch devices, and is also used to coordinate the flow of power between each of the household-level routers through the switch devices.

[0020] In one embodiment, the total energy router comprises:

[0021] A first grid input interface, used to obtain the three-phase alternating current;

[0022] A second grid input interface, used to obtain the single-phase alternating current;

[0023] A three-phase AC / DC conversion device, wherein the input end of the three-phase AC / DC conversion device is electrically connected to the first grid input interface, and the output end of the three-phase AC / DC conversion device is electrically connected to a plurality of sub-center energy routers, for converting the three-phase AC power into the first DC power;

[0024] a single-phase AC / DC conversion device, wherein the input end of the single-phase AC / DC conversion device is electrically connected to the second grid input interface, and the output end of the single-phase AC / DC conversion device is electrically connected to a plurality of the sub-center energy routers, for converting the single-phase AC power into the second DC power; and

[0025] A DC / DC converter device, wherein a first end of the DC / DC converter device is electrically connected to an output end of the three-phase AC / DC converter device, and a second end of the DC / DC converter device is electrically connected to an output end of the single-phase AC / DC converter device, and is used to convert the first DC power into the second DC power, or to convert the second DC power into the first DC power.

[0026] In one embodiment, the total energy router further includes:

[0027] A photovoltaic power distribution interface, electrically connected to an output terminal of the three-phase AC / DC converter;

[0028] An energy storage and power distribution interface, electrically connected to an output terminal of the single-phase AC / DC converter;

[0029] A first power grid output interface, used to output the three-phase alternating current; and

[0030] The second power grid output interface is used to output the single-phase alternating current.

[0031] In one embodiment, the voltages of the first direct current and the second direct current are different.

[0032] In one of the embodiments, the output end of the household router is also provided with a metering device for collecting electricity consumption information.

[0033] A control method for a DC multi-microgrid system is applied to the DC multi-microgrid system described in any one of the above embodiments, the method comprising:

[0034] Controlling the photovoltaic power generation device and / or the energy storage device to supply power to the load through the control device, and determining whether the power supply of the photovoltaic power generation device and the energy storage device meets the power demand of the load;

[0035] If it is determined that the power supply of the photovoltaic power generation device and the energy storage device does not meet the power demand of the load, the three-phase AC power or the single-phase AC power, the first DC power and the second DC power are controlled to competitively output so that the load can operate normally.

[0036] In one embodiment, the step of controlling the photovoltaic power generation device and / or the energy storage device to supply power to the load by the control device and determining whether the power supply of the photovoltaic power generation device and the energy storage device is sufficient includes:

[0037] Controlling the photovoltaic power generation device to supply power to the load through the control device, and determining whether the output voltage of the photovoltaic power generation device meets the power demand of the load;

[0038] If it is determined that the output voltage of the photovoltaic power generation device does not meet the power demand of the load, the remaining power of the energy storage device is obtained, and based on the power setting threshold, it is determined whether to control the energy storage device to supply power to the load;

[0039] If the remaining power is greater than the power setting threshold, the energy storage device is controlled to supply power to the load, and it is determined whether the power supply of the photovoltaic power generation device and the energy storage device meets the power demand of the load.

[0040] Compared with the prior art, the above-mentioned DC multi-microgrid system and control method converts three-phase AC and / or single-phase AC into the first DC and the second DC through the main energy router, and outputs three-phase AC, single-phase AC, the first DC and the second DC to multiple sub-center energy routers. Each sub-center energy router outputs three-phase AC or single-phase AC, the first DC and the second DC to each of the household-level routers through multiple groups of output interfaces, so that one sub-center energy router can achieve access to multiple household-level DC microgrids. At the same time, the control device in each household-level router controls the photovoltaic power generation device, the energy storage device, the three-phase AC or single-phase AC, the first DC and the second DC bidding output according to the preset rules to enable the load to operate normally, and cooperates with the sub-center energy router to coordinate the flow of electric energy between each of the household-level routers through the sub-center energy router to achieve orderly sharing of energy between DC microgrids, avoid the problems of redundancy and uneconomical existence in the system, and improve the power supply stability and reliability of the DC microgrid. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A structural block diagram of a DC multi-microgrid system provided in one embodiment of the present application;

[0042] Figure 2 A schematic diagram of the structure of a household router provided in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of the structure of a sub-center energy router provided in one embodiment of the present application;

[0044] Figure 4 A schematic diagram of the structure of a total energy router provided in one embodiment of the present application;

[0045] Figure 5 This is a flow chart of a control method for a DC multi-microgrid system provided in one embodiment of the present application.

[0046] 10 DC Multi-Microgrid System

[0047] 100 Total Energy Router

[0048] 101 Three-phase AC

[0049] 102 Single-phase AC

[0050] 110 First grid input interface

[0051] 120 Second power grid input interface

[0052] 130 Three-phase AC / DC converter

[0053] 140 Single-phase AC / DC converter

[0054] 150 DC / DC converter devices

[0055] 160 Photovoltaic power distribution interface

[0056] 170 Energy storage distribution interface

[0057] 180 First grid output interface

[0058] 190 Second power grid output interface

[0059] 200 Points Central Energy Router

[0060] 201 AC output interface

[0061] 202 First DC output interface

[0062] 203 Second DC output interface

[0063] 204 Switching Devices

[0064] 210 points central control device

[0065] 300 household router

[0066] 301 Load

[0067] 302 Measuring equipment

[0068] 310 Control Device

[0069] 320 Photovoltaic power generation device

[0070] 330 Energy Storage Device DETAILED DESCRIPTION

[0071] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.

[0072] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0074] See also Figure 1 An embodiment of the present application provides a DC multi-microgrid system 10, comprising: a total energy router 100, a plurality of sub-center energy routers 200, and a plurality of household-level routers 300. The input end of the total energy router 100 is used to obtain three-phase alternating current 101 and single-phase alternating current 102. The total energy router 100 is used to convert the three-phase alternating current 101 and / or the single-phase alternating current 102 into a first direct current and a second direct current, and output the three-phase alternating current 101, the single-phase alternating current 102, the first direct current, and the second direct current.

[0075] Each of the sub-center energy routers 200 is electrically connected to the output end of the main energy router 100. The sub-center energy router 200 is provided with a plurality of groups of output interfaces. Each group of the output interfaces is used to output the three-phase alternating current 101 or the single-phase alternating current 102, the first direct current, and the second direct current. Each of the household-level routers 300 is electrically connected to a group of the output interfaces. The output end of the household-level router 300 is used to electrically connect to a load 301. The household-level router 300 is used to obtain the three-phase alternating current 101 or the single-phase alternating current 102, the first direct current, and the second direct current.

[0076] The household router 300 includes a control device 310, a photovoltaic power generation device 320, and an energy storage device 330. The control device 310 is used to control the photovoltaic power generation device 320, the energy storage device 330, the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to bid and output so that the load 301 can operate normally. The sub-center energy router 200 is also used to coordinate the flow of power between each household router 300.

[0077] It can be understood that the specific structure of the total energy router 100 is not limited, as long as it has the function of converting the three-phase AC 101 and / or the single-phase AC 102 into the first DC and the second DC, and outputting the three-phase AC 101, the single-phase AC 102, the first DC and the second DC. In one embodiment, the total energy router 100 can be composed of a three-phase AC / DC converter, a single-phase AC / DC converter and an air switch. The total energy router 100 can also be composed of a three-phase AC / DC converter, a DC / DC converter, a single-phase AC / DC converter and a voltage detection device. In one embodiment, the specific voltage of the three-phase AC 101 can be 380V AC. In one embodiment, the specific voltage of the single-phase AC 102 can be 220V AC.

[0078] In one embodiment, the total energy router 100 is used to convert the three-phase AC power 101 and / or the single-phase AC power 102 into the first DC power and the second DC power, which means that: the total energy router 100 can convert the three-phase AC power 101 into the first DC power, and then convert the first DC power into the second DC power; the total energy router 100 can also convert the single-phase AC power 102 into the second DC power, and then convert the second DC power into the first DC power. The total energy router 100 can also convert the three-phase AC power 101 into the first DC power, and convert the single-phase AC power 102 into the second DC power. That is, no matter which of the above conversion methods is adopted by the total energy router 100, it only needs to ensure that the total energy router 100 can output the three-phase AC power 101, the single-phase AC power 102, the first DC power and the second DC power.

[0079] In one embodiment, the voltages of the first direct current and the second direct current are different. Specifically, the voltage of the first direct current can be selected according to actual needs. For example, the voltage range of the first direct current can be 600V-750V. The voltage of the second direct current can also be selected according to actual needs. For example, the voltage range of the second direct current can be 375-400V.

[0080] In one embodiment, the total energy router 100 also has the function of detecting whether the DC parameters such as voltage, current, power, and electricity of each output port are normal. Specifically, a controller is provided in the total energy router 100. The output end of the total energy router 100 is provided with the three-phase AC output port 101, the single-phase AC output port 102, the first DC output port, and the second DC output port, and each output port is provided with a voltage detection device. The voltage of each port is detected by the voltage detection device, and the detected voltage of each port is sent to the controller. Then, the controller compares the voltage of each port with the output voltage threshold of each port, thereby determining whether the voltage of each output port is normal based on the comparison result, thereby avoiding the phenomenon of undervoltage and the like, and ensuring the reliability of power supply.

[0081] In one embodiment, the voltage detection device can also be replaced by other DC power parameter detection devices (such as current detection devices, power detection devices, power detection devices, etc.). The controller monitors the total energy router 100 and provides power consumption information of the router, thereby providing power consumption information for the scheduling of the microgrid system.

[0082] It can be understood that the specific structure of the sub-center energy router 200 is not limited, as long as it has the function of coordinating the flow of power between each of the household-level routers 300. In one embodiment, the sub-center energy router 200 can be composed of a sub-center controller, an AC / DC converter, and a plurality of contactors in conjunction with a transmission line. In one embodiment, the sub-center energy router 200 can also be composed of a sub-center controller, an AC / DC converter, a plurality of micro-break switches, and a plurality of contactors in conjunction with a transmission line.

[0083] In one embodiment, the sub-center energy router 200 is provided with a power distribution input interface. The three-phase alternating current 101 or the single-phase alternating current 102, the first direct current and the second direct current outputted by the total energy router 100 are received through the power distribution input interface. Then, the three-phase alternating current 101 or the single-phase alternating current 102, the first direct current and the second direct current are respectively divided into multiple public bus distribution interfaces, and multiple groups of output interfaces are formed. Among them, each group of the output interfaces includes a first direct current public bus distribution interface, a second direct current public bus distribution interface and an alternating current public bus distribution interface, so that each group of the output interfaces can output the three-phase alternating current 101 or the single-phase alternating current 102, the first direct current and the second direct current. In one embodiment, a micro-break switch is provided on each public bus. The micro-break switch can be an air switch. In one embodiment, each micro-break switch is in the open state by default.

[0084] Each of the household routers 300 is electrically connected to a group of the output interfaces. That is, each of the sub-center energy routers 200 can realize access to multiple household DC microgrids (i.e., the household routers 300). Through the loop control of the sub-center controller in the sub-center router 200, the ring network scenarios of different household DC microgrids can be realized, such as the household DC microgrid can choose pure AC access, or AC / DC access, or can choose to realize DC ring network access with other household DC microgrids.

[0085] It can be understood that the specific structure of the control device 310 is not limited, as long as it has the function of controlling the photovoltaic power generation device 320, the energy storage device 330, the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to arbitrate output so that the load 301 can operate normally. In one embodiment, the control device 310 can be a single-chip microcomputer. In one embodiment, the control device 310 can also be a control chip. In one embodiment, the control device 310 is electrically connected to the photovoltaic power generation device 320, the energy storage device 330 and the sub-center energy router 200 respectively.

[0086] It is understood that the specific structure of the photovoltaic power generation device 320 is not limited, as long as it has the function of photovoltaic power generation. In one embodiment, the photovoltaic power generation device 320 can be composed of a solar panel and a DC / DC. In one embodiment, the photovoltaic power generation device 320 can also be composed of a solar panel, an AC / DC and a controller. In one embodiment, the energy storage device 330 can be an energy storage battery.

[0087] In one embodiment, the control device 310 is used to control the photovoltaic power generation device 320, the energy storage device 330, the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to competitively output so that the load 301 can operate normally. This means that the control device 310 is configured to first control the photovoltaic power generation device 320 to supply power to the load 301. Figure 2 As shown, at this time, the control device 310 can control KM6, KM9, KM3, KM10 and KM11 to be turned on (at this time, KM1, KM2, KM4, KM5, KM7 and KM8 are in the disconnected state), that is, the photovoltaic power generation device 320 supplies power to the load 301.

[0088] In one embodiment, the control device 310 is used to control the on and off of KM1, KM2, KM3, KM4, KM5, KM6, KM7, KM8, KM9, KM10 and KM11 respectively. KM1, KM2, KM3, KM4, KM5, KM6, KM7, KM8, KM9, KM10 and KM11 are all controllable switch devices.

[0089] During the power supply process, the control device 310 monitors in real time whether the output voltage of the photovoltaic power generation device 320 meets the power demand of the load 301. Specifically, the control device 310 can monitor whether the output voltage of the photovoltaic power generation device 320 meets the power demand of the load 301 through the DC / DC on the power supply branch of the photovoltaic power generation device 320. In one embodiment, the control device 310 can compare the output voltage of the photovoltaic power generation device 320 with the load voltage of the load 301. If the output voltage of the photovoltaic power generation device 320 is greater than or equal to the load voltage, it is determined that the output voltage of the photovoltaic power generation device 320 can meet the power demand of the load 301 at this time.

[0090] If the output voltage of the photovoltaic power generation device 320 is less than the load voltage, it is determined that the output voltage of the photovoltaic power generation device 320 does not meet the power demand of the load 301 at this time. At this time, the control device 310 can determine the remaining power of the energy storage device 330. Specifically, the control device 310 can obtain the remaining power of the energy storage device 330 through the DC / DC on the power supply branch of the energy storage device 330, and compare the remaining power with the power setting threshold. If the remaining power is greater than the power setting threshold, the control device 310 controls the energy storage device 330 to discharge (i.e., controls KM7 to turn on) so that the load 301 can operate normally, so that the household router 300 can achieve internal power supply (i.e., self-sufficiency).

[0091] In one embodiment, if the photovoltaic power generation device 320 and the energy storage device 330 are both powered normally, but the power supply of the photovoltaic power generation device 320 and the energy storage device 330 cannot meet the power demand of the load 301, the control device 310 controls the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to electronically bid and output so that the load 301 can operate normally. Specifically, the control device 310 can control the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to electronically bid and output so that the load 301 can operate normally through various controllable switch devices (KM1, KM2, KM4, KM5 and KM8). In one embodiment, the control device 310 can also realize the power supply of the three-phase AC power 101 and / or the first DC power and / or the second DC power through various controllable switch devices.

[0092] For example, when the three-phase AC power 101 is required to supply power, the control device 310 can control KM1, KM2 and KM9 to be turned on. When the first DC power is required to supply power, the control device 310 can control KM4, KM5 and KM9 to be turned on. When the second DC power is required to supply power, the control device 310 can control KM8 to be turned on. At the same time, the above three power supply modes can supply power in any combination of modes. That is, the load 301 can be powered by the three-phase AC power 101 and / or the first DC power and / or the second DC power at the same time.

[0093] In one embodiment, if the output voltage of the photovoltaic power generation device 320 does not meet the power demand of the load 301, and the control device 310 detects that the remaining power of the energy storage device 330 is less than or equal to the power setting threshold, the control device 310 controls the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to competitively output so that the load 301 can operate normally.

[0094] In one embodiment, the control device 310 may also preferentially determine whether the remaining power of the energy storage device 330 meets the discharge demand; if the discharge demand is met, the control device 310 preferentially controls the energy storage device 330 to discharge (i.e., to supply power to the load 301); if the discharge demand is not met, the control device 310 controls the photovoltaic power generation device 320 to supply power to the load 301.

[0095] In one embodiment, if the photovoltaic power generation device 320 and the energy storage device 330 are both supplying power normally, but the power supply of the photovoltaic power generation device 320 and the energy storage device 330 cannot meet the power demand of the load 301, then the control device 310 is also used to send the power demand to the sub-center controller in the sub-center energy router 200, and detect whether other household-level routers 300 have excess power through the sub-center controller.

[0096] Specifically, the sub-center controller can communicate data with the control device 310 in other household-level routers 300 to determine whether other household-level routers 300 have excess power. If other household-level routers 300 have excess power, the sub-center controller can cooperate with the contactor and the switching switch in the household-level router 300 to electrically connect the household-level router 300 with other household-level routers 300 with excess power, that is, provide power support to the current household-level router 300 through other household-level routers 300 with excess power, so that the load 301 can operate normally. In the above manner, the function of coordinating the flow of power between each household-level router 300 through the sub-center energy router 200 can be realized, thereby realizing the orderly sharing of energy between DC microgrids (i.e., the household-level routers 300), avoiding the redundancy and uneconomical problems of the DC multi-microgrid system 10, and improving the power supply stability and reliability of the DC microgrid.

[0097] In one embodiment, when other household-level routers 300 with excess power provide power support to the current household-level router 300, the output end of the other household-level routers 300 outputs the first direct current or the second direct current. As can be seen from the above content, the source of the first direct current received by the household-level router 300 can be the first direct current directly output by the sub-center energy router 200, or the first direct current output by other household-level routers 300. Similarly, the source of the second direct current received by the household-level router 300 can be the second direct current directly output by the sub-center energy router 200, or the second direct current output by other household-level routers 300.

[0098] In one embodiment, the control device 310 is also used to determine whether the DC parameters such as voltage, current, power, and quantity of each power supply branch are normal. Specifically, the control device 310 can detect the DC parameters of each power supply branch through the DC parameter detection device ( Figure 2ET / QT in the DC power grid detects the DC power parameters of each power supply branch, and compares the detected DC power parameters on each power supply branch with the DC power parameter threshold of each branch, thereby determining whether the DC power parameters of each output power supply branch are normal based on the respective comparison results, thereby ensuring the reliability of power supply. In one embodiment, in the DC multi-microgrid system 10, the hierarchical and graded output of voltage can be achieved through DC / DC, such as from DC 750V to DC 400V to DC 48V and finally output to the load 301.

[0099] In this embodiment, the three-phase AC 101 and / or the single-phase AC 102 are converted into the first DC and the second DC through the main energy router 100, and the three-phase AC, the single-phase AC, the first DC and the second DC are output to multiple sub-center energy routers 200. Each sub-center energy router 200 outputs the three-phase AC or single-phase AC, the first DC and the second DC to each of the household-level routers through multiple groups of output interfaces, so that one sub-center energy router 200 can achieve access to multiple household-level DC microgrids. At the same time, the control device 310 in each household-level router 300 controls the photovoltaic power generation device 320, the energy storage device 330, the three-phase AC or single-phase AC, the first DC and the second DC bidding output according to the preset rules to enable the load to operate normally, and coordinates the flow of electric energy between each household-level router 300 through the sub-center energy router 200, so as to realize the orderly sharing of energy between DC microgrids and improve the power supply stability and reliability of the DC microgrid.

[0100] In one embodiment, the preset rule includes: the control device 310 controls the photovoltaic power generation device 320 and / or the energy storage device 330 to supply power to the load 301, and determines whether the power supply of the photovoltaic power generation device 320 and the energy storage device 330 meets the power demand of the load 301. If it is determined that the power supply of the photovoltaic power generation device 320 and the energy storage device 330 does not meet the power demand of the load 301, the control device 310 controls the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to competitively output so that the load 301 operates normally.

[0101] In one embodiment, the control device 310 is further used to obtain the remaining power of the energy storage device 330, and determine whether to control the energy storage device 330 to discharge based on the power setting threshold. Specifically, the control device 310 may compare the remaining power with the power setting threshold; if the remaining power is greater than the power setting threshold, the control device 310 may control the energy storage device 330 to discharge. If the remaining power is less than or equal to the power setting threshold, the control device 310 controls the energy storage device 330 not to discharge.

[0102] In one embodiment, the output end of the household router 300 is also provided with a metering device 302 for collecting power consumption information. In one embodiment, the metering device 302 is an electric meter. The metering device 302 collects power consumption information in real time to facilitate subsequent power consumption statistics and prediction.

[0103] See also Figure 3 In one embodiment, the output interface includes an AC output interface 201, a first DC output interface 202, and a second DC output interface 203. The AC output interface 201, the first DC output interface 202, and the second DC output interface 203 are each provided with a switch device 204. Each of the switch devices 204 is used to control the conduction and disconnection of the AC output interface 201, the first DC output interface 202, or the second DC output interface 203.

[0104] In one embodiment, the switch device 204 may be a contactor. In one embodiment, the AC output interface 201, the first DC output interface 202, and the second DC output interface 203 are all provided with a switch device 204, which means: the AC output interface 201 is provided with the switch device 204, the first DC output interface 202 is provided with the switch device 204, and the second DC output interface 203 is also provided with the switch device 204. In one embodiment, each interface corresponds to a branch. Each branch is also provided with a micro-break switch, and the conduction and disconnection of the branch are controlled by the cooperation of the micro-break switch and the switch device 204.

[0105] In one embodiment, an AC / DC converter is further provided in the sub-center energy router 200. The AC / DC converter is used to convert the three-phase AC power 101 or the single-phase AC power 102 received by the power distribution input interface into the first DC power, and output the first DC power through the first DC power output interface 202.

[0106] In one embodiment, the sub-center energy router 200 includes: a sub-center control device 210. The sub-center control device 210 is electrically connected to the plurality of switch devices 204 and the plurality of control devices 310. The sub-center control device 210 is used to control the conduction and disconnection of each of the switch devices 204. The sub-center control device 210 is also used to coordinate the flow of power between each of the household-level routers 300 through the switch devices 204.

[0107] In one embodiment, the specific structure of the sub-center control device 210 is not limited, and it only needs to have the function of controlling the conduction and disconnection of each of the switch devices 204, and coordinating the flow of power between each of the household-level routers 300 through the switch devices 204. In one embodiment, the sub-center control device 210 can be an MCU (micro control unit). In one embodiment, the sub-center control device 210 can be a control chip.

[0108] In one embodiment, when the power distribution input interface of the sub-center control device 210 receives sufficient power (i.e., the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power), each of the switch devices 204 is in the on state. In one embodiment, the sub-center control device 210 can coordinate the flow of power between each of the household-level routers 300 through the switch devices 204 according to the power request of the control device 310 in each of the household-level routers 300, so as to ensure the normal operation of the load 301 electrically connected to the output end of each of the household-level routers 300.

[0109] See also Figure 4 In one embodiment, the total energy router 100 includes: a first grid input interface 110, a second grid input interface 120, a three-phase AC / DC conversion device 130, a single-phase AC / DC conversion device 140, and a DC / DC conversion device 150. The first grid input interface 110 is used to obtain the three-phase AC power 101. The second grid input interface 120 is used to obtain the single-phase AC power 102. The input end of the three-phase AC / DC conversion device 130 is electrically connected to the first grid input interface 110. The output end of the three-phase AC / DC conversion device 130 is electrically connected to a plurality of the sub-center energy routers 200. The three-phase AC / DC conversion device 130 is used to convert the three-phase AC power 101 into the first DC power.

[0110] The input end of the single-phase AC / DC conversion device 140 is electrically connected to the second grid input interface 120. The output end of the single-phase AC / DC conversion device 140 is electrically connected to the plurality of sub-center energy routers 200. The single-phase AC / DC conversion device 140 is used to convert the single-phase AC power 102 into the second DC power. The first end of the DC / DC conversion device 150 is electrically connected to the output end of the three-phase AC / DC conversion device 130. The second end of the DC / DC conversion device 150 is electrically connected to the output end of the single-phase AC / DC conversion device 140. The DC / DC conversion device 150 is used to convert the first DC power into the second DC power, or convert the second DC power into the first DC power.

[0111] In one embodiment, the total energy router 100 further includes: a photovoltaic power distribution interface 160, an energy storage power distribution interface 170, a first grid output interface 180, and a second grid output interface 190. The photovoltaic power distribution interface 160 is electrically connected to the output end of the three-phase AC / DC converter 130. The energy storage power distribution interface 170 is electrically connected to the output end of the single-phase AC / DC converter 140. The first grid output interface 180 is used to output the three-phase AC power 101. The second grid output interface 190 is used to output the single-phase AC power 102.

[0112] In one embodiment, the photovoltaic power distribution interface 160 can be used to electrically connect to an external photovoltaic power generation device, and provide power to the total energy router 100 through the photovoltaic power generation device. Similarly, the energy storage power distribution interface 170 can be used to electrically connect to an external energy storage battery, and provide power to the total energy router 100 through the energy storage battery. In this way, the stability and reliability of the power supply of the DC multi-microgrid system 10 can be ensured.

[0113] See also Figure 5 An embodiment of the present application provides a control method for a DC multi-microgrid system, which is applied to the DC multi-microgrid system 10 described in any of the above embodiments. The method includes:

[0114] S102 : Control the photovoltaic power generation device 320 and / or the energy storage device 330 to supply power to the load 301 through the control device 310 , and determine whether the power supply of the photovoltaic power generation device 320 and the energy storage device 330 meets the power demand of the load 301 .

[0115] In one embodiment, the specific structures of the control device 310, the photovoltaic power generation device 320 and the energy storage device 330 can adopt the structures described in the above embodiments, and the description is not repeated here. Determining whether the power supply of the photovoltaic power generation device 320 and the energy storage device 330 meets the power demand of the load 301 through the control device 310 means: the output voltage of the photovoltaic power generation device 320 and the load voltage of the load 301 can be obtained through the control device 310, and the output voltage of the photovoltaic power generation device 320 is compared with the load voltage.

[0116] If the output voltage of the photovoltaic power generation device 320 is greater than or equal to the load voltage, it is determined that the output voltage of the photovoltaic power generation device 320 can meet the power demand of the load 301. If the output voltage of the photovoltaic power generation device 320 is less than the load voltage, it is determined that the output voltage of the photovoltaic power generation device 320 does not meet the power demand of the load 301, and step S104 is executed.

[0117] S104: If it is determined that the power supply of the photovoltaic power generation device 320 and the energy storage device 330 does not meet the power demand of the load 301, the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power are controlled to competitively output so that the load 301 can operate normally.

[0118] In one embodiment, the control device 310 can control the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power to quantize and output so that the load 301 can operate normally. Figure 2 As shown, the three-phase AC power 101 or the single-phase AC power 102, the first DC power and the second DC power can be controlled by the control device 310 through various controllable switch devices (KM1, KM2, KM4, KM5 and KM8) to quantize the output so that the load 301 can operate normally. In one embodiment, the control device 310 can also realize the power supply of the three-phase AC power 101 and / or the first DC power and / or the second DC power through various controllable switch devices.

[0119] For example, when the three-phase AC power 101 is required to supply power, the control device 310 can control KM1, KM2 and KM9 to be turned on. When the first DC power is required to supply power, the control device 310 can control KM4, KM5 and KM9 to be turned on. When the second DC power is required to supply power, the control device 310 can control KM8 to be turned on. At the same time, the above three power supply modes can supply power in any combination of modes. That is, the load 301 can be powered by the three-phase AC power 101 and / or the first DC power and / or the second DC power at the same time.

[0120] In one embodiment, the power demand can also be sent to the sub-center controller in the sub-center energy router 200 through the control device 310, and the sub-center controller can detect whether other household-level routers 300 have excess power. If it is detected that other household-level routers 300 have excess power, the sub-center controller can coordinate to switch the excess power of other household-level routers 300 to the current household-level router 300 through the switch to provide power support, so that the load 301 can operate normally. That is, the function of coordinating the flow of power between each household-level router 300 through the sub-center energy router 200 is realized, so as to realize the orderly sharing of energy between DC microgrids (i.e., the household-level routers 300), avoid the redundancy and uneconomical problems of the DC multi-microgrid system 10, and improve the power supply stability and reliability of the DC microgrid.

[0121] In one embodiment, step S102 includes: controlling the photovoltaic power generation device 320 to supply power to the load 301 through the control device 310, and determining whether the output voltage of the photovoltaic power generation device 320 meets the power demand of the load 301. If it is determined that the output voltage of the photovoltaic power generation device 320 does not meet the power demand of the load 301, the remaining power of the energy storage device 330 is obtained, and based on the power setting threshold, it is determined whether to control the energy storage device 330 to supply power to the load 301. If the remaining power is greater than the power setting threshold, the energy storage device 330 is controlled to supply power to the load 301, and it is determined whether the power supply of the photovoltaic power generation device 320 and the energy storage device 330 meets the power demand of the load 301.

[0122] In one embodiment, determining whether the output voltage of the photovoltaic power generation device 320 meets the power demand of the load 301 by the control device 310 is specifically as follows: the control device 310 can obtain the output voltage of the photovoltaic power generation device 320 through the DC / DC on the power supply branch of the photovoltaic power generation device 320, and compare it with the load voltage of the load 301. If the output voltage of the photovoltaic power generation device 320 is greater than or equal to the load voltage, it is determined that the output voltage of the photovoltaic power generation device 320 at this time can meet the power demand of the load 301, otherwise it does not meet the demand.

[0123] In one embodiment, obtaining the remaining power of the energy storage device 330 and determining whether to control the energy storage device 330 to supply power to the load 301 based on the power setting threshold means that the control device 310 can obtain the remaining power of the energy storage device 330 through the DC / DC on the power supply branch of the energy storage device 330, and compare the remaining power with the power setting threshold. If the remaining power is greater than the power setting threshold, the control device 310 determines to control the energy storage device 330 to discharge (i.e., to supply power to the load 301), otherwise it does not discharge.

[0124] In summary, the present application converts the three-phase AC 101 and / or the single-phase AC 102 into the first DC and the second DC through the total energy router 100, and outputs the three-phase AC, single-phase AC, the first DC and the second DC to multiple sub-center energy routers 200. Each sub-center energy router 200 outputs the three-phase AC or single-phase AC, the first DC and the second DC to each of the household-level routers through multiple groups of output interfaces, so that one sub-center energy router 200 can achieve access to multiple household-level DC microgrids. At the same time, the control device 310 in each household-level router 300 controls the photovoltaic power generation device 320, the energy storage device 330, the three-phase AC or single-phase AC, the first DC and the second DC bidding output according to the preset rules to enable the load to operate normally, and coordinates the flow of electric energy between each household-level router 300 through the sub-center energy router 200, so as to realize the orderly sharing of energy between DC microgrids and improve the power supply stability and reliability of the DC microgrid.

[0125] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A DC multi-microgrid system, characterized in that: include: A total energy router, wherein the input end of the total energy router is used to obtain three-phase alternating current and single-phase alternating current respectively, and the total energy router is used to convert the three-phase alternating current and / or the single-phase alternating current into a first direct current and a second direct current, and output the three-phase alternating current, the single-phase alternating current, the first direct current and the second direct current; A plurality of sub-center energy routers, each of which is electrically connected to the output end of the main energy router, and the sub-center energy router is provided with a plurality of groups of output interfaces, each group of the output interfaces is used to output the three-phase alternating current or the single-phase alternating current, the first direct current and the second direct current; as well as A plurality of household-level routers, each of which is electrically connected to a group of the output interfaces, the output end of the household-level router is used to electrically connect to a load, and the household-level router is used to obtain the three-phase alternating current or the single-phase alternating current, the first direct current, and the second direct current; The household router includes a control device, a photovoltaic power generation device, and an energy storage device, wherein the control device is used to control the photovoltaic power generation device, the energy storage device, the three-phase alternating current or the single-phase alternating current, the first direct current, and the second direct current to competitively output so that the load operates normally; The control device is configured to preferentially control the photovoltaic power generation device and / or the energy storage device to supply power to the load, and determine whether the power supply of the photovoltaic power generation device and the energy storage device meets the power demand of the load; If it is determined that the power supply of the photovoltaic power generation device and the energy storage device does not meet the power demand of the load, the control device controls the three-phase AC power or the single-phase AC power, the first DC power and the second DC power to competitively output so that the load can operate normally; The control device is electrically connected to the photovoltaic power generation device, the energy storage device and the sub-center energy router respectively, and the control device is also used to obtain the remaining power of the energy storage device and determine whether to control the energy storage device to discharge based on the power setting threshold; The sub-center energy router is also used to coordinate the flow of power between the household-level routers.

2. The DC multi-microgrid system according to claim 1, characterized in that: The source of the first direct current received by the household router is the first direct current directly output by the sub-center energy router or the first direct current output by other household routers; The source of the second direct current received by the household-level router is the second direct current directly output by the sub-center energy router or the second direct current output by other household-level routers.

3. The DC multi-microgrid system according to claim 1, characterized in that: The control device is used to compare the remaining power with the power setting threshold. If the remaining power is greater than the power setting threshold, the control device controls the energy storage device to discharge. If the remaining power is less than or equal to the power setting threshold, the control device controls the energy storage device not to discharge.

4. The DC multi-microgrid system according to claim 1, characterized in that: The output interface includes an AC output interface, a first DC output interface and a second DC output interface. The AC output interface, the first DC output interface and the second DC output interface are all provided with switching devices, and each of the switching devices is used to control the conduction and disconnection of the AC output interface or the first DC output interface or the second DC output interface.

5. The DC multi-microgrid system according to claim 4, characterized in that: The sub-center energy router includes: The sub-center control device is electrically connected to the plurality of switch devices and the plurality of control devices respectively, and is used to control the on and off of each of the switch devices, and is also used to coordinate the flow of power between each of the household-level routers through the switch devices.

6. The DC multi-microgrid system according to claim 1, characterized in that: Total Energy Router includes: A first grid input interface, used to obtain the three-phase alternating current; A second grid input interface, used to obtain the single-phase alternating current; A three-phase AC / DC conversion device, wherein the input end of the three-phase AC / DC conversion device is electrically connected to the first grid input interface, and the output end of the three-phase AC / DC conversion device is electrically connected to a plurality of sub-center energy routers, for converting the three-phase AC power into the first DC power; a single-phase AC / DC conversion device, wherein the input end of the single-phase AC / DC conversion device is electrically connected to the second grid input interface, and the output end of the single-phase AC / DC conversion device is electrically connected to a plurality of the sub-center energy routers, for converting the single-phase AC power into the second DC power; and A DC / DC converter device, wherein a first end of the DC / DC converter device is electrically connected to an output end of the three-phase AC / DC converter device, and a second end of the DC / DC converter device is electrically connected to an output end of the single-phase AC / DC converter device, and is used to convert the first DC power into the second DC power, or to convert the second DC power into the first DC power.

7. The DC multi-microgrid system according to claim 6, characterized in that: The total energy router also includes: A photovoltaic power distribution interface, electrically connected to an output terminal of the three-phase AC / DC converter; An energy storage and power distribution interface, electrically connected to an output terminal of the single-phase AC / DC converter; A first power grid output interface, used to output the three-phase alternating current; and The second power grid output interface is used to output the single-phase alternating current.

8. The DC multi-microgrid system according to any one of claims 1 to 7, characterized in that: The voltages of the first direct current and the second direct current are different.

9. The DC multi-microgrid system according to claim 8, characterized in that: The output end of the household router is also provided with a metering device for collecting electricity consumption information.

10. A control method for a DC multi-microgrid system, characterized in that: Applied to the DC multi-microgrid system according to any one of claims 1 to 9, the method comprises: Controlling the photovoltaic power generation device and / or the energy storage device to supply power to the load through the control device, and determining whether the power supply of the photovoltaic power generation device and the energy storage device meets the power demand of the load; If it is determined that the power supply of the photovoltaic power generation device and the energy storage device does not meet the power demand of the load, the three-phase AC power or the single-phase AC power, the first DC power and the second DC power are controlled to competitively output so that the load can operate normally.

11. The control method of a DC multi-microgrid system according to claim 10, characterized in that: The steps of controlling the photovoltaic power generation device and / or the energy storage device to supply power to the load through the control device and determining whether the power supply of the photovoltaic power generation device and the energy storage device is sufficient include: Controlling the photovoltaic power generation device to supply power to the load through the control device, and determining whether the output voltage of the photovoltaic power generation device meets the power demand of the load; If it is determined that the output voltage of the photovoltaic power generation device does not meet the power demand of the load, the remaining power of the energy storage device is obtained, and based on the power setting threshold, it is determined whether to control the energy storage device to supply power to the load; If the remaining power is greater than the power setting threshold, the energy storage device is controlled to supply power to the load, and it is determined whether the power supply of the photovoltaic power generation device and the energy storage device meets the power demand of the load.

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