DC-DC power module flexible distribution method and system for multi-source micro-grid

Abstract

The invention relates to the field of micro-grids, and discloses a DC-DC direct current power module flexible distribution method and system for a multi-source micro-grid. Comprising a multi-source direct-current power supply unit, a multi-source direct-current bus switch matrix unit, a multi-source direct-current bus unit, an input switch matrix unit, a DC-DC direct-current power unit module, an output switch matrix unit, a direct-current energy storage unit and a direct-current load unit, through the technical scheme provided by the invention, sharing and flexible distribution of the DC-DC direct current power modules among the subsystems in the micro-grid can be realized, the utilization rate of the DC-DC direct current power modules is improved, and the electric energy loss caused by multiple times of conversion of the DC-DC direct current power modules in the electric energy transmission process is reduced.

Description

Technical Field

[0001] The present invention relates to the field of power grids, and in particular to a method and system for flexible allocation of direct current power modules for multi-source microgrids. Background Art

[0002] In recent years, with the development of technologies such as photovoltaic, wind power, other new energy and power grid, multi-energy microgrid (referred to as multi-source microgrid), energy storage, charging piles, DC compressors and microgrids, multi-source microgrids have achieved great development and application, and AC bus, AC / DC hybrid bus and DC bus technologies have appeared in multi-source microgrids. Among them, in the microgrid with DC bus, there are a large number of DC-DC power modules in each subsystem on the DC bus. Each subsystem is connected to the DC bus through the DC-DC power module to realize the power conversion and transmission between the subsystems.

[0003] In the existing technology, the DC-DC power module is exclusively used by each subsystem. The sharing and flexible allocation of the DC-DC power module can be partially realized within each subsystem, but the sharing and flexible allocation of the DC-DC power module between subsystems cannot be realized.

[0004] For example, the DC-DC power module of photovoltaic is in working state under sunlight during the day and in idle state at night; the energy storage system is in working state during the charging stage in the valley period of electricity price and the discharging stage in the peak period of electricity price, and is in idle state at other times;

[0005] The DC-DC power module of the charging pile is in working state when charging, and is in idle state when no vehicle is charging. The overall utilization rate of the above DC-DC power modules is not high, and the investment is wasted because the DC-DC power modules cannot be shared between subsystems. There are multiple DC-DC power module conversions in the power transmission between systems. For example, the photovoltaic system connects the photovoltaic modules to the DC bus after conversion by the DC-DC module, and the DC load such as the charging pile converts the bus voltage to the car charging voltage through the DC-DC module to charge the car. The existing technology has the problem of large energy loss due to multiple conversions. There are DC-DC power modules with multiple functions in the system. The photovoltaic system uses a unidirectional DC-DC power module with MPPT, the charging pile system without V2G uses a unidirectional DC-DC power module, and the energy storage system and the charging pile with V2G use a bidirectional DC-DC power module. The system has a large number of spare parts. The PCS is configured according to the maximum load. The PCS itself has a power regulation function. The DC-DC power module in the subsystem also has a power regulation function. There are two power regulation problems in the application. The two power regulation problems lead to the problem of power loss in two power regulation.

[0006] The existing multi-source microgrid technology uses unidirectional DC-DC power modules and bidirectional DC-DC power modules. For example, energy storage systems and charging piles with V2G use bidirectional DC-DC power modules, while charging piles, photovoltaic systems, etc. use unidirectional DC-DC power modules. Bidirectional DC-DC power modules have complex electronic circuits, many electronic components, high costs, and unidirectional power modules and bidirectional power modules cannot be used as backup for each other. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a DC-DC direct current power module flexible distribution system for a multi-source microgrid, including a multi-source direct current power supply unit, a multi-source direct current bus switch matrix unit, a multi-source direct current bus unit, an input switch matrix unit, a DC-DC direct current power unit module, an output switch matrix unit, a direct current energy storage unit, a direct current load unit, a PCS unit, and a V2G vehicle unit.

[0008] The multi-source DC power supply unit may include a power grid power supply unit and a DC power generation unit. The AC power of the power grid power supply unit is converted into DC power by a transformer unit and a rectifier unit. The DC power generation unit is composed of a photovoltaic panel group.

[0009] The PCS unit is an inverter, the input of the PCS unit is connected to the output switch matrix unit, and the output of the PCS unit is connected to the secondary end of the grid transformer, so as to realize the function of supplying power to the grid by the DC energy storage unit, DC power generation unit and V2G new energy vehicle unit in the DC microgrid;

[0010] When the V2G car unit is charged, it is connected to the output end of the output switch matrix unit as a DC load unit; when the V2G car unit is discharged, the V2G car unit is connected to the input of the output switch matrix unit, the output switch matrix unit is connected to the DC end of the PCS unit, the PCS unit converts the DC power output by the V2G car unit into AC power, the PCS AC end is connected to the secondary end of the transformer, and the primary end of the transformer is connected to the power grid;

[0011] The multi-source DC power supply unit is connected to the multi-source DC bus unit through the multi-source DC bus switch matrix unit, and the multi-source DC bus switch matrix unit is connected to the multi-source DC bus unit; the multi-source DC bus unit is connected to the input switch matrix unit; the input switch matrix unit and the output switch matrix unit are respectively connected to the DC-DC power unit module; the DC load unit and the DC energy storage unit are respectively connected to the output switch matrix;

[0012] The DC-DC direct current power unit module is used for sharing and flexible allocation among direct current load units, direct current energy storage units and multi-source direct current power supply units;

[0013] The multi-source DC power supply unit provides electric energy to the DC load unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit;

[0014] When the DC energy storage unit is disconnected from the multi-source DC switch matrix, the multi-source DC power supply unit provides electric energy to the DC energy storage unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit;

[0015] When the DC energy storage unit is disconnected from the output switch matrix unit, the DC energy storage unit provides electric energy to the DC load unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit;

[0016] The multi-source DC bus switch matrix unit, the multi-source DC power supply unit, and the DC energy storage unit are respectively connected to the input of the multi-source DC bus switch matrix unit, and the output of the multi-source DC bus switch matrix unit is connected to the input of the multi-source DC bus unit;

[0017] The input switch matrix unit is used to connect each DC bus in the multi-source DC bus unit to the input of the DC-DC power unit respectively;

[0018] The output switch matrix unit is used to connect each output of the DC-DC power unit with each DC load of the DC load unit, and to connect each output of the DC-DC power unit with each DC energy storage unit of the DC energy storage unit.

[0019] Preferably, the DC-DC direct current power module is used for charging and discharging a direct current energy storage unit, including the following process:

[0020] The charging of the DC energy storage unit includes: the multi-source DC bus switch matrix selects the grid power supply unit or the DC power generation power supply. If the grid unit is powered, the power supply of the grid power supply unit is transformed and rectified into DC power, and connected to the grid DC bus of the multi-source DC bus unit through the multi-source DC bus switch matrix; if the DC power generation power supply is used, the DC power generation bus of the multi-source DC bus unit is connected through the multi-source DC bus switch matrix; the multi-source DC bus is converted into the power and voltage required by the DC energy storage unit through the control switch of the input switch matrix unit and the DC-DC power unit, completing the electric energy storage of the DC energy storage unit;

[0021] The discharge of the DC energy storage unit includes: the multi-source DC bus switch matrix unit is disconnected from the energy storage unit, the energy storage unit is connected to the multi-source DC bus via the multi-source DC bus switch matrix unit, the multi-source DC bus is connected to the DC-DC power unit module via the input switch matrix, the DC-DC power unit is converted into the power and voltage required by the DC energy storage unit, and the discharge to the DC load unit is completed.

[0022] Preferably, when the DC-DC direct current power module is used in a direct current load unit, it comprises:

[0023] When the multi-source DC power supply unit supplies power, the multi-source DC power supply selects grid power supply or DC power generation as the power to be provided. The multi-source DC power supply unit connects the grid power supply or DC power generation to the corresponding multi-source DC bus through the multi-source DC switch matrix unit. The multi-source DC bus is connected to the DC-DC power module of the DC-DC power unit module through the input switch matrix unit. The DC-DC power module is connected to the DC load of the DC load unit through the output switch matrix, so as to provide power to the DC load.

[0024] When the DC energy storage unit supplies power, the DC energy storage unit is connected to the corresponding multi-source DC bus through the multi-source DC switch matrix unit, the multi-source DC bus is connected to the DC-DC power module of the DC-DC power unit module through the input switch matrix unit, and the DC-DC power module is connected to the DC load of the DC load unit through the output switch matrix, so as to provide electrical energy to the DC load.

[0025] When the DC energy storage unit is charged or discharged, the occupied DC-DC power module is released, and the DC-DC power module participates in the flexible allocation.

[0026] Preferably, the DC power generation unit includes photovoltaic panel power generation, and the photovoltaic panel power generation includes:

[0027] When the photovoltaic panel generates electricity: the photovoltaic panel is connected to the multi-source DC bus through the multi-source DC bus switch matrix unit, the multi-source DC bus is connected to the DC-DC power unit module through the input switch matrix, and the DC-DC power unit converts the power and voltage required by the DC load unit to complete the power supply to the DC load unit;

[0028] The photovoltaic panel is connected to the multi-source DC bus through the multi-source DC bus switch matrix unit, and the multi-source DC bus is connected to the DC-DC power unit module through the input switch matrix. The DC-DC power unit converts the power and voltage required by the DC energy storage unit to complete the power supply to the DC energy storage unit.

[0029] When the photovoltaic panel is idle: the photovoltaic panel is disconnected from the multi-source DC bus through the multi-source DC bus switch matrix unit, the DC-DC power module is released, and the DC-DC power module participates in flexible allocation.

[0030] A DC-DC direct current power module flexible allocation method for a multi-source microgrid is applied to the DC-DC direct current power module flexible allocation system for a multi-source microgrid, comprising:

[0031] When allocated to the DC power supply unit, the DC load unit and the DC energy storage unit, the DC-DC power unit module is in an occupied state. When not occupied, the n DC-DC power units in the DC-DC power unit module are in an idle state. According to the power requirements of the DC power supply unit, the DC load unit and the DC energy storage unit, and according to the size of the single power requirement, the flexible allocation of the DC-DC power unit is realized through the control switches of the input switch matrix unit and the output switch matrix unit. The single power requirement is:

[0032] The power requirement of a single DC load = the power requirement of the DC power supply unit, DC load unit and DC energy storage unit

[0033] When m*DC-DC module power ≥ single DC load power demand ≥ (m+1)*DC-DC module power, and n≥m, select m DC-DC power modules for allocation; when m*DC-DC module power ≥ single DC load power demand ≥ (m+1)*DC-DC module power, and m≥n, select n DC-DC power modules for allocation;

[0034] When n=0, the newly added DC load power allocation can be in a waiting state. After the online DC load unit releases the DC-DC power module, the power allocation is performed according to the flexible allocation method 1.

[0035] When n=0, the newly added DC load power distribution can be customized by the user to release the online DC load unit to achieve flexible power distribution.

[0036] When the DC load unit finishes working, the occupied DC-DC direct current power module is released, and the DC-DC direct current power module participates in the flexible allocation.

[0037] Furthermore, the output voltage range of the multi-source DC power supply unit and the output voltage range of the DC energy storage unit are consistent with the input voltage range of the DC-DC power module, and the output voltage range of the DC-DC power unit module is consistent with the input voltage range of the DC energy storage unit and the DC load unit.

[0038] Furthermore, the input voltage range of the PCS unit is consistent with the output voltage of the V2G vehicle unit, the output voltage range of the DC energy storage unit and the output voltage range of the multi-source DC power supply unit.

[0039] Furthermore, the DC-DC direct current power module for the multi-source microgrid is a unidirectional DC-DC direct current power module.

[0040] The beneficial effects of the present invention are: unifying the functions and technical parameters of DC-DC power modules, realizing the sharing and flexible allocation of DC-DC power modules among subsystems in a microgrid, improving the utilization rate of DC-DC power modules, and reducing the power loss caused by multiple conversions of DC-DC power modules during power transmission; using non-controlled rectification technology in the power grid transformer link, and power control is regulated and controlled by the DC-DC power module, thereby reducing the power loss caused by two power adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the principle of a DC-DC direct current power module flexible distribution system for a multi-source microgrid;

[0042] Figure 2 A schematic diagram of the topological structure of a multi-source microgrid of the present invention;

[0043] Figure 3 Schematic diagram of the existing DC microgrid topology structure. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0045] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0046] like Figure 1 As shown, a DC-DC direct current power module flexible distribution system for a multi-source microgrid includes a multi-source direct current power supply unit, a multi-source direct current bus switch matrix unit, a multi-source direct current bus unit, an input switch matrix unit, a DC-DC direct current power unit module, an output switch matrix unit, a direct current energy storage unit, a direct current load unit, a PCS unit, and a V2G vehicle unit.

[0047] The multi-source DC power supply unit may include a power grid power supply unit and a DC power generation unit. The AC power of the power grid power supply unit is converted into DC power by a transformer unit and a rectifier unit. The DC power generation unit is composed of a photovoltaic panel group.

[0048] The PCS unit is an inverter, the input of the PCS unit is connected to the output switch matrix unit, and the output of the PCS unit is connected to the secondary end of the grid transformer, so as to realize the function of supplying power to the grid by the DC energy storage unit, DC power generation unit and V2G new energy vehicle unit in the DC microgrid;

[0049] When the V2G car unit is charged, it is connected to the output end of the output switch matrix unit as a DC load unit; when the V2G car unit is discharged, the V2G car unit is connected to the input of the output switch matrix unit, the output switch matrix unit is connected to the DC end of the PCS unit, the PCS unit converts the DC power output by the V2G car unit into AC power, the PCS AC end is connected to the secondary end of the transformer, and the primary end of the transformer is connected to the power grid, so that the V2G car supplies power to the large grid.

[0050] The multi-source DC power supply unit is connected to the multi-source DC bus unit through the multi-source DC bus switch matrix unit, and the multi-source DC bus switch matrix unit is connected to the multi-source DC bus unit; the multi-source DC bus unit is connected to the input switch matrix unit; the input switch matrix unit and the output switch matrix unit are respectively connected to the DC-DC power unit module; the DC load unit and the DC energy storage unit are respectively connected to the output switch matrix;

[0051] The DC-DC direct current power unit module is used for sharing and flexible allocation among direct current load units, direct current energy storage units and multi-source direct current power supply units;

[0052] The multi-source DC power supply unit provides electric energy to the DC load unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit;

[0053] When the DC energy storage unit is disconnected from the multi-source DC switch matrix, the multi-source DC power supply unit provides electric energy to the DC energy storage unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit;

[0054] When the DC energy storage unit is disconnected from the output switch matrix unit, the DC energy storage unit provides electric energy to the DC load unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit;

[0055] The multi-source DC bus switch matrix unit, the multi-source DC power supply unit, and the DC energy storage unit are respectively connected to the input of the multi-source DC bus switch matrix unit, and the output of the multi-source DC bus switch matrix unit is connected to the input of the multi-source DC bus unit;

[0056] The input switch matrix unit is used to connect each DC bus in the multi-source DC bus unit to the input of the DC-DC power unit respectively;

[0057] The output switch matrix unit is used to connect each output of the DC-DC power unit with each DC load of the DC load unit, and to connect each output of the DC-DC power unit with each DC energy storage unit of the DC energy storage unit.

[0058] The DC-DC direct current power module is used for charging and discharging the direct current energy storage unit, including the following process:

[0059] The charging of the DC energy storage unit includes: the multi-source DC bus switch matrix selects the grid power supply unit or the DC power generation power supply. If the grid unit is powered, the power supply of the grid power supply unit is transformed and rectified into DC power, and connected to the grid DC bus of the multi-source DC bus unit through the multi-source DC bus switch matrix; if the DC power generation power supply is used, the DC power generation bus of the multi-source DC bus unit is connected through the multi-source DC bus switch matrix; the multi-source DC bus is converted into the power and voltage required by the DC energy storage unit through the control switch of the input switch matrix unit and the DC-DC power unit, completing the electric energy storage of the DC energy storage unit;

[0060] The discharge of the DC energy storage unit includes: the multi-source DC bus switch matrix unit is disconnected from the energy storage unit, the energy storage unit is connected to the multi-source DC bus via the multi-source DC bus switch matrix unit, the multi-source DC bus is connected to the DC-DC power unit module via the input switch matrix, the DC-DC power unit is converted into the power and voltage required by the DC energy storage unit, and the discharge to the DC load unit is completed.

[0061] When the DC-DC direct current power module is used for a direct current load unit, it comprises:

[0062] When the multi-source DC power supply unit supplies power, the multi-source DC power supply selects grid power supply or DC power generation as the power to be provided. The multi-source DC power supply unit connects the grid power supply or DC power generation to the corresponding multi-source DC bus through the multi-source DC switch matrix unit. The multi-source DC bus is connected to the DC-DC power module of the DC-DC power unit module through the input switch matrix unit. The DC-DC power module is connected to the DC load of the DC load unit through the output switch matrix, so as to provide power to the DC load.

[0063] When the DC energy storage unit supplies power, the DC energy storage unit is connected to the corresponding multi-source DC bus through the multi-source DC switch matrix unit, the multi-source DC bus is connected to the DC-DC power module of the DC-DC power unit module through the input switch matrix unit, and the DC-DC power module is connected to the DC load of the DC load unit through the output switch matrix, so as to provide electrical energy to the DC load.

[0064] When the DC energy storage unit finishes charging or discharging, the occupied DC-DC power module is released, and the DC-DC power module participates in flexible allocation.

[0065] The DC power generation unit includes photovoltaic panel power generation, and the photovoltaic panel power generation includes:

[0066] When the photovoltaic panel generates electricity: the photovoltaic panel is connected to the multi-source DC bus through the multi-source DC bus switch matrix unit, the multi-source DC bus is connected to the DC-DC power unit module through the input switch matrix, and the DC-DC power unit converts the power and voltage required by the DC load unit to complete the power supply to the DC load unit;

[0067] The photovoltaic panel is connected to the multi-source DC bus through the multi-source DC bus switch matrix unit, and the multi-source DC bus is connected to the DC-DC power unit module through the input switch matrix. The DC-DC power unit converts the power and voltage required by the DC energy storage unit to complete the power supply to the DC energy storage unit.

[0068] When the photovoltaic panel is idle: the photovoltaic panel is disconnected from the multi-source DC bus through the multi-source DC bus switch matrix unit, the DC-DC power module is released, and the DC-DC power module participates in flexible allocation.

[0069] A DC-DC direct current power module flexible allocation method for a multi-source microgrid is applied to the DC-DC direct current power module flexible allocation system for a multi-source microgrid, comprising:

[0070] When allocated to the DC power supply unit, the DC load unit and the DC energy storage unit, the DC-DC power unit module is in an occupied state. When not occupied, the n DC-DC power units in the DC-DC power unit module are in an idle state. According to the power requirements of the DC power supply unit, the DC load unit and the DC energy storage unit, and according to the size of the single power requirement, the flexible allocation of the DC-DC power unit is realized through the control switches of the input switch matrix unit and the output switch matrix unit. The single power requirement is:

[0071] The power requirement of a single DC load = the power requirement of the DC power supply unit, DC load unit and DC energy storage unit

[0072] When m*DC-DC module power ≥ single DC load power demand ≥ (m+1)*DC-DC module power, and n≥m, select m DC-DC power modules for allocation; when m*DC-DC module power ≥ single DC load power demand ≥ (m+1)*DC-DC module power, and m≥n, select n DC-DC power modules for allocation;

[0073] When n=0, the newly added DC load power allocation can be in a waiting state. After the online DC load unit releases the DC-DC power module, the power allocation is performed according to the flexible allocation method 1.

[0074] When n=0, the newly added DC load power distribution can be customized by the user to release the online DC load unit to achieve flexible power distribution.

[0075] When the DC load unit finishes working, the occupied DC-DC power module is released, and the DC-DC power module participates in flexible allocation.

[0076] The output voltage range of the multi-source DC power supply unit and the output voltage range of the DC energy storage unit are consistent with the input voltage range of the DC-DC power module, and the output voltage range of the DC-DC power unit module is consistent with the input voltage range of the DC energy storage unit and the DC load unit.

[0077] The input voltage range of the PCS unit is consistent with the output voltage of the V2G vehicle unit, the output voltage range of the DC energy storage unit and the output voltage range of the multi-source DC power supply unit.

[0078] The DC-DC direct current power module for the multi-source microgrid is a unidirectional DC-DC direct current power module.

[0079] The existing multi-source microgrid topology method is to connect multiple subsystems on the DC bus. Taking the commonly used multi-source DC systems such as power grid, photovoltaic, energy storage and charging piles as an example, the DC microgrid topology of the existing technology is as follows: Figure 3. The DC-DC power modules of photovoltaic, energy storage and charging piles are all connected to the DC bus. The DC-DC module of the charging pile system can realize the sharing and flexible allocation of multiple charging piles, but the DC-DC modules of each subsystem cannot be shared and flexibly allocated. The photovoltaic, energy storage and charging pile subsystems are equipped with corresponding DC-DC modules. The photovoltaic power generation energy is converted into DC bus voltage by the photovoltaic system DC-DC module. The charging pile system transmits the power from the DC bus to the car battery of the charging pile through the DC-DC module. The power of the photovoltaic system needs to be converted by the DC-DC power module twice, resulting in two power conversion losses during the conversion process. In each subsystem, photovoltaic uses a unidirectional DC-DC power module, energy storage uses a bidirectional DC-DC power module, charging piles without V2G function in the charging pile system use a unidirectional DC-DC module, and charging piles with V2G function use a bidirectional DC-DC module. There are differences in the functions and technical parameters of the DC-DC power modules of multiple subsystems, and it is impossible to realize the sharing and universality of DC-DC power modules.

[0080] The present invention needs to solve the problem of consistency of functions and technical parameters of DC-DC power modules of multi-source microgrid systems, solve the problem that DC-DC power modules in multiple subsystems cannot be shared and flexibly allocated, solve the problem that DC-DC modules of multi-source microgrids use unidirectional modules instead of bidirectional modules, solve the problem of flexible allocation of electric energy of multi-source subsystems, and solve the problem of electric energy loss caused by multiple DC-DC module conversions between subsystems.

[0081] The present invention adopts uncontrolled rectification technology in the power grid transformer link, and the power control function is adjusted by a DC-DC direct current power module, thereby solving the power loss of two power adjustments and reducing investment costs.

[0082] The topological structure of the multi-source microgrid of the present invention is as follows: Figure 2 As shown, the system at least includes

[0083] 100 is a multi-source DC bus, the rated DC voltage of the multi-source DC bus may be 750VDC or other rated DC voltages in priority, and is composed of 2 or more DC multi-source buses;

[0084] 300 is a DC-DC power unit module. The DC-DC power module can give priority to unidirectional function. The function and technical parameters of the DC-DC power module meet the technical requirements of each subsystem.

[0085] 700 is a DC load unit, and the DC load is one or more;

[0086] 200 is an input switch matrix unit, the switches of which realize connection between each of more than 100 DC bus sources and the input of 300 DC-DC power units;

[0087] 400 is an output switch matrix unit, and the switches of the output switch matrix unit 400 realize the connection between each output or each group of outputs of 300 DC-DC direct current power units and each direct current load of 700 direct current load units, or can selectively realize the connection between each output or each group of outputs of 300 DC-DC direct current power units and each direct current energy storage unit of 500 direct current energy storage units;

[0088] Optionally, 500 is a DC energy storage unit, and the number of DC energy storage units may be one or more;

[0089] 600 is a multi-source DC bus switch matrix, the number of which is the number of DC energy storage units; the controllable switches of the 600 multi-source DC bus switch matrix realize the connection between 500 DC energy storage units and the multi-source DC bus.

[0090] Optionally, 800 is a DC power generation unit, which can be selected as a DC power generation unit, such as photovoltaic DC power generation, or a power generation unit in which AC power generation is rectified to DC, such as a wind power generation unit rectified to DC.

[0091] 900 is a grid unit, which can be an AC grid including a transformer and an uncontrolled rectifier unit. The 900 unit is optional, and the transformer can be selected with a 380VAC output. The function of the 900 unit is to realize the grid power supply through the transformer and the uncontrolled rectifier unit to output DC power, and connect to the grid DC bus of the 100-source DC bus to realize the function of taking power from the grid. The 900 unit can select the 380VAC output, which can be used for the AC bus to provide AC power for the AC load.

[0092] Optionally, 1000 is an inverter unit, which realizes the inversion of the DC power of the multi-source microgrid DC bus into 380VAC, which can be used as the power supply for the AC bus, or can be used to send power to the grid through the 380VAC of the 900 unit.

[0093] Optionally, 1100 is an AC unit, which may include an AC power generation unit and an AC load.

[0094] The present invention adopts the functions and technical parameters of the DC-DC power modules of a unified multi-source microgrid system, adopts a multi-source DC bus system, realizes input switching through a multi-source DC input switch matrix, realizes output switching through an output switch matrix, realizes sharing and flexible allocation of DC-DC power modules of subsystems of the multi-source microgrid system, solves the energy consumption problem of multiple power conversions between subsystems, and reduces the power loss of multiple conversions of DC-DC power modules during power transmission.

[0095] The present invention divides the DC-DC power module of the multi-source microgrid system into unidirectional function and bidirectional function and unifies them into unidirectional function. The present invention realizes the switching of the power direction of each subsystem by switching the input switch matrix and the output switch matrix, and realizes the unified use of unidirectional DC-DC power modules.

[0096] The present invention realizes the DC-DC direct current power module connected in the middle as a shared unit through a combined control method of an input switch matrix and an output switch matrix, thereby realizing sharing and flexible allocation among subsystems of the DC-DC direct current power module.

[0097] The present invention adopts the method of uncontrolled rectification technology, and the power control is adjusted by the DC-DC direct current power module of each sub-unit, realizing the rectification and power control functions, while reducing the power loss caused by two power adjustments, thereby reducing the total investment cost.

[0098] The present invention unifies the functions and technical parameters of the DC-DC direct current power module and can reduce the number of spare parts.

[0099] The present invention reduces and solves the energy consumption problem of multiple electric energy conversions between subsystems, and reduces electric energy loss during electric energy transmission.

[0100] The present invention realizes sharing and flexible allocation of DC-DC direct current power modules of each subsystem, realizes general improvement of utilization rate of DC-DC direct current power modules, and improves equipment utilization rate.

Claims

1. A DC-DC direct current power module flexible distribution system for multi-source microgrids, characterized in that: It includes a multi-source DC power supply unit, a multi-source DC bus switch matrix unit, a multi-source DC bus unit, an input switch matrix unit, a DC-DC power unit module, an output switch matrix unit, a DC energy storage unit, a DC load unit, a PCS unit, and a V2G vehicle unit. The multi-source DC power supply unit may include a power grid power supply unit and a DC power generation unit. The AC power of the power grid power supply unit is converted into DC power by a transformer unit and a rectifier unit. The DC power generation unit is composed of a photovoltaic panel group. The PCS unit is an inverter, the input of the PCS unit is connected to the output switch matrix unit, and the output of the PCS unit is connected to the secondary end of the grid transformer, so as to realize the function of supplying power to the grid by the DC energy storage unit, DC power generation unit and V2G new energy vehicle unit in the DC microgrid; When the V2G car unit is charged, it is connected to the output end of the output switch matrix unit as a DC load unit; when the V2G car unit is discharged, the V2G car unit is connected to the input of the output switch matrix unit, the output switch matrix unit is connected to the DC end of the PCS unit, the PCS unit converts the DC power output by the V2G car unit into AC power, the PCS AC end is connected to the secondary end of the transformer, and the primary end of the transformer is connected to the power grid; The multi-source DC power supply unit is connected to the multi-source DC bus unit through the multi-source DC bus switch matrix unit, and the multi-source DC bus switch matrix unit is connected to the multi-source DC bus unit; the multi-source DC bus unit is connected to the input switch matrix unit; the input switch matrix unit and the output switch matrix unit are respectively connected to the DC-DC power unit module; the DC load unit and the DC energy storage unit are respectively connected to the output switch matrix; The DC-DC direct current power unit module is used for sharing and flexible allocation among direct current load units, direct current energy storage units and multi-source direct current power supply units; The multi-source DC power supply unit provides electric energy to the DC load unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit; When the DC energy storage unit is disconnected from the multi-source DC switch matrix, the multi-source DC power supply unit provides electric energy to the DC energy storage unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit; When the DC energy storage unit is disconnected from the output switch matrix unit, the DC energy storage unit provides electric energy to the DC load unit via the multi-source DC bus switch matrix unit, the multi-source DC bus unit, the input switch matrix unit, the DC-DC power unit module, and the output switch matrix unit; The multi-source DC bus switch matrix unit, the multi-source DC power supply unit, and the DC energy storage unit are respectively connected to the input of the multi-source DC bus switch matrix unit, and the output of the multi-source DC bus switch matrix unit is connected to the input of the multi-source DC bus unit; The input switch matrix unit is used to connect each DC bus in the multi-source DC bus unit to the input of the DC-DC power unit respectively; The output switch matrix unit is used to connect each output of the DC-DC power unit with each DC load of the DC load unit, and to connect each output of the DC-DC power unit with each DC energy storage unit of the DC energy storage unit.

2. The DC-DC direct current power module flexible distribution system for multi-source microgrid according to claim 1 is characterized in that: The DC-DC direct current power module is used for charging and discharging the direct current energy storage unit, including the following process: The charging of the DC energy storage unit includes: the multi-source DC bus switch matrix selects the grid power supply unit or the DC power generation power supply. If the grid unit is powered, the power supply of the grid power supply unit is transformed and rectified into DC power, and connected to the grid DC bus of the multi-source DC bus unit through the multi-source DC bus switch matrix; if the DC power generation power supply is used, the DC power generation bus of the multi-source DC bus unit is connected through the multi-source DC bus switch matrix; the multi-source DC bus is converted into the power and voltage required by the DC energy storage unit through the control switch of the input switch matrix unit and the DC-DC power unit, completing the electric energy storage of the DC energy storage unit; The discharge of the DC energy storage unit includes: the multi-source DC bus switch matrix unit is disconnected from the energy storage unit, the energy storage unit is connected to the multi-source DC bus via the multi-source DC bus switch matrix unit, the multi-source DC bus is connected to the DC-DC power unit module via the input switch matrix, the DC-DC power unit is converted into the power and voltage required by the DC energy storage unit, and the discharge to the DC load unit is completed.

3. The DC-DC direct current power module flexible distribution system for multi-source microgrid according to claim 1 is characterized in that: When the DC-DC direct current power module is used for a direct current load unit, it comprises: When the multi-source DC power supply unit supplies power, the multi-source DC power supply selects grid power supply or DC power generation as the power to be provided. The multi-source DC power supply unit connects the grid power supply or DC power generation to the corresponding multi-source DC bus through the multi-source DC switch matrix unit. The multi-source DC bus is connected to the DC-DC power module of the DC-DC power unit module through the input switch matrix unit. The DC-DC power module is connected to the DC load of the DC load unit through the output switch matrix, so as to provide power to the DC load. When the DC energy storage unit supplies power, the DC energy storage unit is connected to the corresponding multi-source DC bus through the multi-source DC switch matrix unit, the multi-source DC bus is connected to the DC-DC power module of the DC-DC power unit module through the input switch matrix unit, and the DC-DC power module is connected to the DC load of the DC load unit through the output switch matrix, so as to provide electrical energy to the DC load. When the DC energy storage unit finishes powering or storing energy, the occupied DC-DC power modules are released, and the DC-DC power modules participate in flexible allocation.

4. The DC-DC direct current power module flexible distribution system for multi-source microgrid according to claim 1, characterized in that: The DC power generation unit includes photovoltaic panel power generation, and the photovoltaic panel power generation includes: When the photovoltaic panel generates electricity, the photovoltaic panel is connected to the multi-source DC bus through the multi-source DC bus switch matrix unit, the multi-source DC bus is connected to the DC-DC power unit module through the input switch matrix, and the DC-DC power unit converts the power and voltage required by the DC load unit to complete the power supply to the DC load unit; The photovoltaic panel is connected to the multi-source DC bus through the multi-source DC bus switch matrix unit, and the multi-source DC bus is connected to the DC-DC power unit module through the input switch matrix. The DC-DC power unit converts the power and voltage required by the DC energy storage unit to complete the power supply to the DC energy storage unit. When the photovoltaic panel is idle: the photovoltaic panel is disconnected from the multi-source DC bus through the multi-source DC bus switch matrix unit, the occupied DC-DC power module is released, and the DC-DC power module participates in flexible allocation.

5. A DC-DC direct current power module flexible allocation method for a multi-source microgrid, characterized in that: A DC-DC direct current power module flexible distribution system for a multi-source microgrid as described in any one of claims 1 to 5, comprising: When allocated to the DC power supply unit, the DC load unit and the DC energy storage unit, the DC-DC power unit module is in an occupied state. When not occupied, the n DC-DC power units in the DC-DC power unit module are in an idle state. According to the power requirements of the DC power supply unit, the DC load unit and the DC energy storage unit, and according to the size of the single power requirement, the flexible allocation of the DC-DC power unit is realized through the control switches of the input switch matrix unit and the output switch matrix unit. The single power requirement is: The power requirement of a single DC load = the power requirement of the DC power supply unit, DC load unit and DC energy storage unit When m*DC-DC module power ≥ single DC load power demand ≥ (m+1)*DC-DC module power, and n≥m, select m DC-DC power modules for allocation; when m*DC-DC module power ≥ single DC load power demand ≥ (m+1)*DC-DC module power, and m≥n, select n DC-DC power modules for allocation; When n=0, the newly added DC load power allocation can be in a waiting state. After the online DC load unit releases the DC-DC power module, the power allocation is performed according to the flexible allocation method 1. When n=0, the newly added DC load power distribution can be customized by the user to release the online DC load unit to achieve flexible power distribution. When the DC load unit finishes working, the occupied DC-DC power module is released, and the DC-DC power module participates in flexible allocation.

6. The DC-DC direct current power module flexible allocation method for a multi-source microgrid according to claim 5, characterized in that: The output voltage range of the multi-source DC power supply unit and the output voltage range of the DC energy storage unit are consistent with the input voltage range of the DC-DC power module, and the output voltage range of the DC-DC power unit module is consistent with the input voltage range of the DC energy storage unit and the DC load unit.

7. The DC-DC direct current power module flexible allocation method for a multi-source microgrid according to claim 5, characterized in that: The input voltage range of the PCS unit is consistent with the output voltage of the V2G vehicle unit, the output voltage range of the DC energy storage unit and the output voltage range of the multi-source DC power supply unit.

8. The DC-DC direct current power module flexible allocation method for a multi-source microgrid according to claim 5, characterized in that: The DC-DC direct current power module for the multi-source microgrid is a unidirectional DC-DC direct current power module.

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