Energy increasing type light storage direct flexible system

Abstract

The utility model provides an energy increasing type light storage direct-current flexible system which comprises a direct-current bus, an alternating-current bus and a gas generator. The DC bus is electrically connected with an external power grid through the optical storage DC-flexible AC grid-connected device; the direct-current bus is electrically connected with the photovoltaic power generation equipment through the maximum power tracking device; the direct current bus and the alternating current bus are electrically connected through a direct current-to-alternating current one-way converter; the alternating current bus is electrically connected with alternating current electric equipment; the gas generator is connected with a gas conveying pipeline or a gas storage tank through a pipeline; one path of the power output end of the gas generator is electrically connected with the alternating current bus, and the other path of the power output end of the gas generator is electrically connected with the direct current bus through the alternating current-direct current one-way converter; and the direct current bus is electrically connected with the gas generator through the alternating current-direct current one-way converter. According to the utility model, the gas generator is introduced as a supplement of a power supply, and effective power support can be provided when photovoltaic power is insufficient or suddenly dropped.

Description

Technical Field

[0001] The utility model relates to the technical field of comprehensive energy, and in particular to an energy-boosting photovoltaic storage direct-flexible system. Background Art

[0002] The "PV-storage-direct-flexible" system is an effective and important way to meet the dual carbon requirements and green building in the construction field. It has received policy support from the state, ministries and other levels and positive responses from various aspects of society, and has broad development prospects. The core of the PV-storage-direct-flexible system is "flexibility", which means changing the rigid power consumption at the end into flexible power consumption and improving the elasticity of the load.

[0003] However, the buildings that are currently used for photovoltaic storage and direct flexible buildings have limited space for photovoltaic construction. Even if photovoltaic curtain walls can be built on their exterior walls, the irradiance loss is relatively large due to the inclination and orientation, resulting in actual power generation being much lower than the installed capacity. In addition, due to the dense buildings and small space in cities, it is impossible to install wind power on a large scale, which limits the source of green electricity for photovoltaic storage and direct flexible buildings. Moreover, photovoltaics cannot solve the power supply problem in the evening or at night, resulting in the need to use a large amount of grid electricity at this stage. At present, grid electricity is still mainly coal-fired. Excessive use of grid electricity will reduce the carbon reduction effect, and the carbon emissions of photovoltaic storage and direct flexible buildings will not be further reduced. Utility Model Content

[0004] The purpose of the utility model is to introduce a new power source into the existing system in order to solve the problem of insufficient green power supply in the current conventional photovoltaic storage direct-flexible system.

[0005] To this end, the above-mentioned purpose of the utility model is achieved through the following technical solutions:

[0006] An energy-boosting solar-storage direct-flexible system, comprising a direct current bus, an alternating current bus, and a gas generator;

[0007] The DC bus is electrically connected to the external power grid via a photovoltaic storage DC-flexible AC grid-connected device;

[0008] The DC bus is electrically connected to the photovoltaic power generation equipment via a maximum power tracking device;

[0009] The DC bus and the AC bus are electrically connected via a DC to AC unidirectional converter;

[0010] The AC busbar is electrically connected to the AC power-consuming equipment;

[0011] The gas generator is connected to a gas pipeline or a gas storage tank via a pipeline;

[0012] One of the power output ends of the gas generator is electrically connected to the AC bus, and the other is electrically connected to the DC bus via an AC-to-DC unidirectional converter;

[0013] The DC bus is electrically connected to the gas generator via an AC-to-DC unidirectional converter.

[0014] While adopting the above technical solutions, the present invention can also adopt or combine the following technical solutions:

[0015] As a preferred technical solution of the utility model: the photovoltaic storage DC-flexible AC grid-connected device includes an AC circuit breaker and an AC / DC bidirectional converter.

[0016] As a preferred technical solution of the utility model: the DC bus is electrically connected to the energy storage device and the electric vehicle via a bidirectional DC transformer.

[0017] As a preferred technical solution of the utility model: the DC bus is electrically connected to the DC power-consuming equipment via a unidirectional DC transformer.

[0018] As a preferred technical solution of the utility model: an electric energy meter is provided on the connection line between the photovoltaic storage direct-flexible AC grid-connected device and the external power grid.

[0019] As a preferred technical solution of the utility model: a generator output circuit breaker is provided at the power output end of the gas generator.

[0020] As a preferred technical solution of the utility model: a gas meter is provided at the air inlet end of the gas generator.

[0021] As a preferred technical solution of the present utility model: the voltage of the DC bus is ±375V.

[0022] As a preferred technical solution of the present utility model: the voltage of the AC bus is 380V.

[0023] Taking into account that natural gas pipelines have now entered thousands of households, especially in view of the advancement of transportation technology, conventional pipelines can already transport natural gas containing a certain proportion of hydrogen. In the future, with the advancement of technology, there may also be pipelines for transporting pure hydrogen into every corner of the city. Therefore, gas-fired generators that burn natural gas, natural gas mixed with hydrogen, or pure hydrogen can be introduced as part of the photovoltaic storage direct and flexible system. In the case of insufficient photovoltaic power generation or energy storage, the gas-fired generator can continue to provide clean energy; the energy-enhancing photovoltaic storage direct and flexible system can use a control method similar to the current extended-range new energy vehicle to control the overall operation of the system, which is divided into green electricity priority mode, gas priority mode and hybrid mode. It is flexible in operation and easy to adjust to meet the electricity needs of users. At the same time, it can reduce the cost of use, reduce the coal power consumption of the power grid and reduce carbon emissions.

[0024] The photovoltaic storage direct-flexible system can be called an energy-boosting photovoltaic storage direct-flexible system, or simply a "photovoltaic storage direct-flexible boosting" system.

[0025] Compared with the prior art, the utility model has the following beneficial effects:

[0026] 1) The energy-enhancing photovoltaic storage direct-flexible system provided by the utility model aims to give priority to the consumption of photovoltaic power and reduce the use of grid power. However, considering the instability and volatility of photovoltaic output, a gas generator is introduced as a supplement to the power supply. When the photovoltaic power is insufficient or drops sharply, it can provide effective power support. Photovoltaic power generation, gas generators, and energy storage equipment can be coordinated and supplemented by grid power to meet the power needs of users while achieving multi-objective optimization control such as the lowest operating cost and the lowest carbon emissions.

[0027] 2) The energy-enhancing photovoltaic storage direct-flexible system provided by the utility model combines the currently mature and convenient natural gas supply system, so that the gas supply of the gas generator can be effectively solved, which is why the system uses the gas generator as the energy-enhancing equipment. With the development of hydrogen production and hydrogen transmission technology, it may be possible to use the existing infrastructure to transmit natural gas hydrogen mixed gas or hydrogen in the future, which will further reduce the carbon emission level of gas generators and even achieve the zero-carbon goal of building electricity use.

[0028] 3) The energy-enhancing photovoltaic storage direct-flexible system provided by the utility model is connected to the power grid through a flexible converter, and can perform two-way power interaction with the power grid, and can also operate independently off the grid. After the introduction of the energy-enhancing gas generator, the dependence on the power grid can be further reduced. Considering that the peak power grid electricity price level is higher than the gas power generation cost, and because the proportion of coal-fired power in the power grid is high, the operation of the gas generator can reduce the energy cost and carbon emission level. In addition, because the gas generator provides a large moment of inertia and stable active power, the system has the ability to operate off the grid for a longer period of time, and can also provide stronger inertia support and peak-shaving and frequency regulation capabilities for the power grid.

[0029] 4) The energy-boosting photovoltaic storage direct-flexible system provided by the utility model can directly supply power to the AC load through circuit design when the gas generator is running. If there is excess energy, it can charge the battery to improve the power quality of the AC load and keep the battery above a reasonable power level to ensure its performance and life. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a typical structural diagram of the energy-boosting solar-storage direct-flexible system provided by the utility model.

[0031] Figure 2 This is a control mode diagram of the energy-boosting solar-storage direct-flexible system provided by the utility model. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] An energy-enhancing photovoltaic storage direct-flexible system includes a photovoltaic power generation device (which can be installed on the roof or facade of a building) and a maximum power tracking device (DC / DC), an energy storage device located in the building or an electric car connected to a charging pile, a DC bus, a photovoltaic storage direct-flexible flexible AC grid-connected device, a plurality of DC transformers (DC / DC), a plurality of DC-to-AC devices (DC / AC), a plurality of AC-to-DC devices (AC / DC), a plurality of AC-to-DC bidirectional converters, a gas generator (which can burn natural gas, hydrogen or a natural gas-hydrogen mixture), an AC bus, a gas pipeline or a gas storage tank, etc.

[0034] The photovoltaic storage direct-flexible AC grid-connected device is equipped with an AC / DC bidirectional converter, one end of which is connected to the AC grid and the other end is connected to the DC bus. It is suitable for converting the AC of the grid into DC to supply power to various DC power-consuming devices, and for converting the DC on the DC bus to AC to generate electricity for the grid. It is also suitable for shutting down at an appropriate time, so that the system can be separated from the large grid and operate independently, and there is no energy exchange between the two. The photovoltaic storage direct-flexible AC grid-connected device is equipped with an AC circuit breaker, which is suitable for switching on and off and protecting the flexible AC grid-connected device.

[0035] An electric energy meter is installed between the photovoltaic storage direct current flexible grid-connected device and the power grid. The electric energy meter has a bidirectional metering function, which is suitable for measuring the power generation and power consumption, and settling accounts according to the power generation price and the power consumption price respectively.

[0036] The photovoltaic power generation equipment is connected to the DC bus through a maximum power tracking device (DC / DC), and the electrical energy is transmitted to various DC power-consuming devices through the DC bus.

[0037] Energy storage devices and electric vehicles are connected to the DC bus through a bidirectional DC transformer (DC / DC), and can be used as both power generation equipment and power consumption equipment.

[0038] The DC power equipment in the building is connected to the DC bus through a unidirectional DC transformer (DC / DC).

[0039] The AC electrical equipment in the building is connected to the AC bus, and the DC bus is connected to the AC bus through a DC / AC converter, and electrical energy is transmitted from the DC side to the AC side.

[0040] Gas generators are connected to municipal gas pipeline outlets or gas tanks through dedicated pipelines, and can generate electricity by burning natural gas, hydrogen, or a mixture of natural gas and hydrogen. The generator is connected to the AC busbar through cables or overhead lines, and to the DC busbar through an AC / DC converter (AC / DC).

[0041] An AC circuit breaker is installed at the outlet of the gas generator to switch on and off and protect the generator. A gas meter is installed at the inlet of the gas pipeline to measure the gas used and settle the bill according to the gas price.

[0042] The energy-enhancing photovoltaic storage direct-flexible system provided by the utility model dynamically adjusts the operating mode according to system states and external conditions such as photovoltaic power generation, energy storage, user energy demand, meteorological conditions, grid electricity prices, gas prices or carbon emission restrictions in different time periods. It can adopt green electricity priority mode, gas priority mode and mixed mode, etc. It is flexible in operation, easy to adjust, reduces the cost of use, ensures that the user's electricity demand is met, and achieves the goal of energy saving and low carbon.

[0043] Specifically, if Figure 1 As shown, an energy-enhancing photovoltaic storage direct-flexible system includes: a photovoltaic storage direct-flexible AC grid-connected device 1, and an AC circuit breaker 1-1 and an AC / DC bidirectional converter 1-2 contained therein; a DC bus 2; a photovoltaic power generation device 3 and a maximum power tracking device (DC / DC) 4 thereof; an energy storage device 5 located in a building or an electric car 6 connected to a DC charging pile, and a bidirectional DC transformer (DC / DC) 7; a DC power-consuming device 8, and a unidirectional DC transformer (DC / DC) 9; an AC power-consuming device 10, a DC-to-AC unidirectional converter (DC / AC) 11; an AC bus 12; a gas generator 13, a generator outlet circuit breaker 14, a gas pipeline or a gas storage tank (natural gas, hydrogen, or a natural gas-hydrogen mixture) 15, an AC-to-DC unidirectional converter (AC / DC) 16; an electric energy meter 17; and a gas meter 18.

[0044] In this embodiment, an AC / DC bidirectional converter 1-2 is provided in the photovoltaic storage direct-flexible AC grid-connected device 1, the DC side of the AC / DC bidirectional converter 1-2 is connected to the DC bus 2, and the AC side is connected to the AC circuit breaker 1-1, and the AC circuit breaker 1-1 is connected to the AC grid. The AC / DC bidirectional converter 1-2 is suitable for converting the AC of the grid into DC to supply power to various DC power-consuming devices, and is also suitable for converting the DC on the DC bus to AC to supply power to the grid, and is also suitable for shutting down at an appropriate time, so that the DC system is separated from the large grid and operates independently, and there is no energy exchange between the two.

[0045] In this embodiment, the AC circuit breaker 1-2 is suitable for switching on or off the photovoltaic storage DC-flexible AC grid-connected device. When the protection device detects a short circuit current, abnormal voltage or abnormal frequency in the power grid or the AC grid-connected device, a disconnection command can be issued to the AC circuit breaker 1-2.

[0046] An electric energy meter 17 is provided between the photovoltaic storage direct-flexible AC grid-connected device 1 and the external power grid. The electric energy meter has a bidirectional metering function, and is suitable for measuring the power generation and power consumption respectively, and for settling accounts according to the power generation price and the power consumption price respectively.

[0047] In this embodiment, a building can install several photovoltaic power generation equipment 3 on its roof, facade or surrounding open space. Each group of photovoltaic power generation equipment 3 is connected to the DC bus 2 through a maximum power tracking device (DC / DC) 4, and the electric energy is transmitted to each DC load through the DC bus. The maximum power tracking device (DC / DC) 4 can adjust the output voltage of the photovoltaic equipment in real time to make it emit maximum power under the current meteorological conditions such as irradiation and temperature.

[0048] In this embodiment, the energy storage device 5 and the electric vehicle 6 are connected to the DC bus 2 through a bidirectional DC transformer (DC / DC) 7. The energy storage device 5 and the electric vehicle 6 can be used as both power generation equipment and power consumption equipment. When there is excess photovoltaic power or low grid electricity prices, the electric energy is stored, and when there is insufficient photovoltaic power or high grid electricity prices, the electric energy is released. The aforementioned energy storage device can also be used as an electric energy stabilizer to provide guarantee for the smooth operation and flexible power supply of the entire system.

[0049] In this embodiment, the DC power-consuming equipment in the building (such as computers, televisions, refrigerators, variable-frequency air conditioners, etc.) is connected to the DC bus through a unidirectional DC transformer (DC / DC) 9.

[0050] In this embodiment, the AC electrical equipment 10 (such as a three-phase motor) in the building is connected to the AC bus 12, and the DC bus and the AC bus are connected through a DC to AC unidirectional converter (DC / AC) 11, so that electrical energy can be transmitted from the DC side to the AC side.

[0051] In this embodiment, the gas generator 13 is connected to the municipal gas pipeline or gas storage tank (natural gas, hydrogen or natural gas hydrogen mixture) 15 through a dedicated pipeline, and can generate electricity by burning natural gas, hydrogen or natural gas hydrogen mixture. A gas meter 18 is set between the generator and the external gas supply equipment to measure the gas usage and settle according to the gas price.

[0052] The outlet of the gas generator 13 is connected to the AC circuit breaker 14, and then connected to the AC bus 12 through a cable or an overhead line, and connected to the DC bus 2 through an AC to DC unidirectional converter (AC / DC) 16. The choice of cable or overhead line depends on the relative position of the generator and the building and the surrounding environment. If the distance is short, a cable can be selected, and if the distance is far and the line point is available, an overhead line can be selected.

[0053] In this embodiment, the voltage of the DC bus 2 can be selected as ±375V, the voltage of the AC bus 12 can be selected as 380V, the voltage level of the DC power equipment can be selected as 220V or 48V, the three-phase voltage of the AC power equipment is 380V, and the single-phase voltage is 220V.

[0054] like Figure 2 As shown, the above-mentioned energy-boosting solar-storage direct-flexible system can be controlled in the following three modes:

[0055] 1. Green power priority mode

[0056] When the photovoltaic power generation power is greater than the power required by the power-consuming equipment, such as the period from 9:00 to 15:00 in sunny summer weather, the green power priority mode can be selected. The photovoltaic equipment generates electricity to supply the power-consuming equipment first, and the excess power can be used to charge the energy storage equipment. When the power of the energy storage equipment reaches the upper limit, the excess power can be supplied to the power grid, or by controlling the energy storage charging power, the excess power can be charged and connected to the Internet at the same time. When the photovoltaic power generation power decreases and cannot meet the power required by the power-consuming equipment, the energy storage equipment can generate power to make up for the insufficient energy consumption if the power is greater than the minimum power limit. In this mode, the gas generator is not turned on or the power is taken from the power grid. In this mode, the lower limit of the power of the energy storage equipment is set low, for example, 10%.

[0057] 2. Gas priority mode

[0058] When the photovoltaic power generation is low or in the evening, such as the period from 18:00 to 20:00 in winter, but the load demand of the power equipment is large (generally the electricity price is also high at this time), if the power of the energy storage equipment is also low at this time, after comprehensively considering the gas cost and carbon emission reduction benefits, when the cost of gas-fired power generation is lower than the grid electricity price, the gas priority mode can be adopted. In this mode, start the gas generator, the generator can directly supply power to the AC power equipment through the AC bus, and also supply power to the DC bus through the AC to DC unidirectional converter (AC / DC) to meet the needs of the DC power equipment. When there is surplus power, it can also charge the energy storage equipment. When the power generated by the gas generator cannot meet the needs of the power equipment, it can be powered from the grid. In this mode, the lower limit of the power of the energy storage device is set high, for example, 80%.

[0059] 3. Blending Mode

[0060] When the user's electricity demand is large, the amount of photovoltaic power generation can only meet the electricity demand of some electrical equipment. For example, the sunlight is blocked by clouds during a certain period of the day, and the energy storage power is not enough to support user demand. If the energy storage battery capacity is higher than the minimum set value (for example, 10%), the cost of gas-fired power generation is lower than the grid electricity price, and a hybrid mode can be used. In this mode, the gas generator is started, and the energy storage device is discharged at the same time. The gas generator supplies power to the AC electrical equipment and the DC bus, and the energy storage device supplies power to the DC bus to jointly meet the electricity demand. At this time, the gas and energy storage equipment consume electricity at the same time. If the electricity demand still cannot be met, electricity can be drawn from the grid. In this mode, the lower limit of the energy storage device's power is set low, for example, 10%.

[0061] It should be clear that unless there is a need to supplement power from the grid, in the above three modes, the energy-boosting solar-storage direct-flexible system in this example can operate stably without being connected to the grid.

[0062] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. An energy-boosting solar-storage direct-flexible system, characterized by: The energy-boosting solar-storage direct-flexible system includes a DC bus, an AC bus, and a gas generator; The DC bus is electrically connected to the external power grid via a photovoltaic storage DC-flexible AC grid-connected device; The DC bus is electrically connected to the photovoltaic power generation equipment via a maximum power tracking device; The DC bus and the AC bus are electrically connected via a DC to AC unidirectional converter; The AC busbar is electrically connected to the AC power-consuming equipment; The gas generator is connected to a gas pipeline or a gas storage tank via a pipeline; One of the power output ends of the gas generator is electrically connected to the AC bus, and the other is electrically connected to the DC bus via an AC-to-DC unidirectional converter; The DC bus is electrically connected to the gas generator via an AC-to-DC unidirectional converter.

2. The energy-boosting solar-storage direct-flexible system according to claim 1 is characterized in that: The photovoltaic-storage-direct-flexible AC grid-connected device comprises an AC circuit breaker and an AC / DC bidirectional converter.

3. The energy-boosting solar-storage direct-flexible system according to claim 1 is characterized in that: The DC bus is electrically connected to the energy storage device and the electric vehicle via a bidirectional DC transformer.

4. The energy-boosting solar-storage direct-flexible system according to claim 1 is characterized in that: The DC bus is electrically connected to the DC power-consuming equipment via a unidirectional DC transformer.

5. The energy-boosting solar-storage direct-flexible system according to claim 1 is characterized in that: An electric energy meter is provided on the connection line between the photovoltaic storage direct-flexible alternating current grid-connected device and the external power grid.

6. The energy-boosting solar-storage direct-flexible system according to claim 1, characterized in that: The power output end of the gas generator is provided with a generator output circuit breaker.

7. The energy-boosting solar-storage direct-flexible system according to claim 1 is characterized in that: A gas meter is provided at the air inlet end of the gas generator.

8. The energy-boosting solar-storage direct-flexible system according to claim 1 is characterized in that: The voltage of the DC bus is ±375V.

9. The energy-boosting solar-storage direct-flexible system according to claim 1, characterized in that: The voltage of the AC bus is 380V.

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