CN205104903U - Non - contravariant type light stores up little electric wire netting of direct current system for modern architecture - Google Patents

Abstract

The utility model discloses a non-inverting optical storage DC micro-grid system applied to modern buildings, which includes a DC bus, a photovoltaic power generation unit, an energy storage unit, a mains power supply unit, an energy management unit and a load, and a photovoltaic power generation unit The mains power supply unit is connected to the DC bus through a one-way DC/DC rectifier module, the energy storage unit is connected to the DC bus through a two-way DC/DC conversion module, and the energy management unit includes the main The operation monitoring module communicates with the main control module and can upload the data collected and analyzed to the main control module. The main control module operates according to the set power supply logic according to the data and maintains the bus voltage. Stablize. It has the following advantages: it ensures the quality of the internal power of the microgrid, avoids the feedback of large-scale electric energy to the upper-level mains distribution network, and brings new technologies to the voltage regulation, power regulation and island detection of the upper-level mains distribution network. The problem.

Description

A non-inverting solar-storage DC microgrid system applied to modern buildings

technical field

The utility model relates to a micro-grid system, in particular to a non-inverting light-storage DC micro-grid system applied to modern buildings.

Background technique

With the rapid growth of the national economy, the demand for electricity has grown rapidly. For a long time, the power sector has mainly used the construction of large-scale power plants and ultra-high voltage long-distance transmission lines as solutions, but the investment is large, the construction period is long, and environmental pollution And other disadvantages are also increasingly prominent. At the same time, several large-scale power outages in recent years have also made people aware of the vulnerability of centralized power supply systems. Distributed generation technology (distributedgeneration, DG) came into being under such circumstances.

Distributed generation technology (DG) has the characteristics of flexibility, small size, decentralization, and close to the user side, which can effectively improve the reliability of power consumption and reduce transmission loss. However, distributed power generation technology has disadvantages such as voltage instability and large power fluctuations, which will have a serious impact on the safety and peak regulation of the upper-level power grid. Micro-grid technology solves the contradiction between distributed power generation technology and large power grid. Microgrid refers to a grid form that combines micro power sources, loads and energy storage devices. As an independent whole, it can be connected to the grid or run in island mode.

Combining photovoltaics, energy storage, and loads is called a solar-storage microgrid, and the particularity of photovoltaic materials makes it possible for the solar-storage microgrid to be well applied in modern buildings. For more and more DC loads in modern buildings, such as DC lighting, DC air conditioners, DC refrigerators, DC charging piles, etc., the optical storage microgrid adopts the DC bus transmission form to have better power quality and less power than the AC bus. loss and other advantages. With the promotion of technologies such as DC home appliances and the large-scale application of photovoltaic power generation technology, there is a broad space for development of solar-storage DC microgrids.

The operation modes of DC microgrid mainly include grid-connected operation and island operation. The traditional grid-connected operation means that the microgrid absorbs power from the large grid through the rectification of the mains and transmits power to the large grid through the inverter link. This method can well ensure the reliability of the load in the microgrid and the power of the microgrid. quality, but in the form of inverter operation, the DC microgrid will have a greater impact on the upper-level distribution network, fundamentally changing the one-way power flow of the distribution network, and there will be new problems such as voltage regulation, power fluctuations, and unplanned islands . The island operation mode means that the microgrid relies on the internal micro power supply and energy storage system to supply power to the internal load independently, and has no common connection point with the upper power grid. This operation mode has high requirements for power supply reliability, so a large-scale energy storage system is required , and its long-term charging and discharging will reduce the life of the energy storage system. Considering the economics of the energy storage system, the DC microgrid operating in an isolated island has not been widely used.

Utility model content

The utility model provides a non-inversion type light-storage DC micro-grid system applied to modern buildings, which overcomes the shortcomings of the prior art described in the background art.

The technical scheme that the utility model solves its technical problem adopts is:

A non-inverting solar-storage DC micro-grid system applied to modern buildings, which includes a DC bus, a photovoltaic power generation unit, an energy storage unit, a mains power supply unit, an energy management unit, and a load. The photovoltaic power generation unit passes through a one-way The DC/DC rectifier module is connected to the DC bus, the mains power supply unit is connected to the DC bus through a unidirectional AC/DC rectifier module, the energy storage unit is connected to the DC bus through a bidirectional DC/DC conversion module, and the energy management The unit includes a main control module and an operation monitoring module that is installed in each unit of the microgrid system and monitors the operating status of each unit. The operation monitoring module communicates with the main control module and can collect and analyze the obtained The data is uploaded to the main control module, and the main control module controls the photovoltaic power generation unit, the energy storage unit and the mains power supply unit to operate according to the set power supply logic and maintain the stability of the bus voltage according to the data.

In one embodiment: the energy storage unit includes a lead-acid battery.

In an embodiment: the load includes a DC load, and the DC bus can be directly connected to the DC load or connected to the DC load through a unidirectional DC/DC conversion module.

In an embodiment: the load includes an AC load, and the DC bus is connected to the AC load through a unidirectional DC/AC conversion module.

In an embodiment, the energy management unit further includes an insulation monitoring module for monitoring the grounding status of the DC bus and each unit, and the insulation monitoring module is connected to the main control module by communication.

In one embodiment: the rated voltage of the DC bus is 380V.

In an embodiment: the DC load includes a DC charging pile, a DC inverter air conditioner, a DC lighting, a DC power distribution interface, and a DC refrigerator.

In an embodiment: the AC load includes an AC charging pile and an AC distribution box.

Compared with the background technology, this technical solution has the following advantages:

1. The non-inverting solar-storage DC microgrid system is connected to the upper-level mains unit in a non-inverting form, that is, the mains is only connected to the DC bus through a unidirectional AC/DC conversion module (rectifier converter), and the AC The /DC converter does not have an inverter function and cannot feed back excess electricity to the mains. In the whole system, the utility power acts as an energy "transmitter" rather than a "receiver" of energy. On the one hand, this design ensures a relatively independent internal energy supply and high power quality of the microgrid, and on the other hand, it avoids the feedback of large-scale electric energy to the upper-level mains power distribution network, and contributes to the upper-level mains power distribution network. Voltage regulation, power regulation, and islanding detection introduce new problems.

2. The non-inverting solar-storage DC microgrid system adopts the DC bus power supply form inside, and connects the photovoltaic power generation unit, the mains power supply unit and the load, which is different from the AC bus connection used in the traditional microgrid, which requires an inverter link Supply power to DC loads, simplify microgrid power supply lines, and avoid energy loss caused by inverter conversion.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Fig. 1 shows a system schematic diagram of a non-inverting solar-storage DC microgrid system applied to modern buildings described in the present invention.

detailed description

Please refer to Figure 1, a non-inverting solar-storage DC microgrid system applied to modern buildings, which includes a DC bus 10, a photovoltaic power generation unit 20, an energy storage unit 30, a mains power supply unit 40, an energy management unit 50 and load.

In this embodiment, the rated voltage of the DC bus 10 is 380V. The photovoltaic power generation unit 20 is connected to the DC bus 10 through the unidirectional DC/DC rectifier module 1, and converts the unstable high-voltage direct current (in the fluctuation range of 300-700V) generated by it into a stable stable direct current of about 380V. The unidirectional DC/DC rectifier module 1 has an MPPT controller. The mains power supply unit 40 is connected to the DC bus 10 through the unidirectional AC/DC rectification module 2, and rectifies and converts the 220V AC mains power into a stable DC power of about 380V. The bus bars 10 are connected to realize bidirectional power flow between the energy storage unit 30 and the DC bus bar 10 . In this embodiment, the energy storage unit 30 may be a lead-acid battery.

The load includes a DC load. The fluctuation range of the DC bus 10 in this embodiment is ±5%, and the voltage value range is between 360V-400V. The DC bus 10 can be directly connected to the DC load, and can be used for a rated voltage of 380V. DC air conditioners 61, DC charging piles 62, etc. are directly powered, or connected to DC loads through the unidirectional DC/DC conversion module 4, which can provide DC refrigerators 63, DC LED lighting 64, DC Power distribution interface and many other electronic devices.

The load also includes an AC load, the DC bus is connected to the AC load through the unidirectional DC/AC conversion module 5, and is used for a 220V AC load. The electric vehicle with power supply interface is practical.

The energy management unit 50 includes a main control module and an operation monitoring module that is arranged in each unit of the microgrid system and monitors the operating status of each unit. The operation monitoring module is connected to the main control module by communication and can collect, The data obtained by analysis is uploaded to the main control module, and the main control module controls the photovoltaic power generation unit, the energy storage unit and the mains power supply unit to operate according to the set power supply logic and maintain the stability of the bus voltage according to the data. Specifically, the main control module respectively controls the unidirectional DC/DC rectifier 1 connected to the photovoltaic power generation unit 20 and the bidirectional DC/DC conversion connected to the energy storage unit 30 according to the obtained operating status data of each unit of the system according to the set power supply logic. The current power supply is determined by turning on or off the unidirectional AC/DC rectifier 2 connected to the mains power supply unit 40 and the mains power supply unit 40 .

The energy management unit also includes an insulation monitoring module for monitoring the grounding status of the DC bus and each unit, and the insulation monitoring module is communicatively connected with the main control module.

In this embodiment, the operation monitoring module and the insulation monitoring module are connected to the main control module by RS485 bus.

The non-inverting optical-storage DC micro-grid system described in the utility model is a three-power supply system. Considering energy saving and economical factors, the power supply logic of the three power sources here is photovoltaic power generation unit 20 > mains power supply unit 40 > energy storage unit 30 . Specifically, it can be divided into the following four situations: 1. When the power generated by the photovoltaic power generation unit 20 is greater than the load power, the energy storage unit 30 is fully charged, and the photovoltaic power generation unit 20 operates in a constant voltage mode, that is, the power generated by the photovoltaic power generation unit 20 is only The load power needs to be satisfied, and the MPPT controller does not have to work at the maximum power point. At this time, the DC bus voltage is greater than 375V, and the AC mains power supply unit 40 is in a standby state; 2. When the power generated by the photovoltaic power generation unit 20 is greater than the load power, the storage The energy unit 30 is not fully charged, the photovoltaic power generation unit 20 first works in the maximum power mode of the MPPT controller to charge the energy storage unit 30, and gradually smoothes to the floating charge of the energy storage unit, and then enters the first situation; 3. The generating power of the power generation unit 20 is less than the load power. At this time, the bus voltage drops below 375V, and the mains power supply unit 40 starts to output current to balance the DC bus voltage, so that the DC bus voltage rises to the normal operating value; 4. When the mains power supply unit When a power failure occurs at 40, the energy storage unit 30 acts as a backup power supply to supply power to the load. The specific function of the energy storage unit 30 in this system is that when the power generated by the photovoltaic power generation unit 20 is greater than the load power, the energy storage unit 30 cooperates with the photovoltaic power generation unit 20 to maintain the stability of the DC bus voltage; The generated power is less than the load power, the photovoltaic power generation unit 20 works in the maximum power mode of the MPPT controller, and when the DC bus voltage drops below 360V (set as required), the energy storage unit 30 starts to supply power to ensure the continuous power supply of the system .

The above is only a preferred embodiment of the utility model, so the scope of implementation of the utility model cannot be limited accordingly, that is, the equivalent changes and modifications made according to the patent scope of the utility model and the contents of the specification should still belong to this utility model. within the scope of utility models.

Claims (8)

1. A non-inverting type photo-storage DC micro-grid system applied to modern buildings, characterized in that: it includes a DC bus, a photovoltaic power generation unit, an energy storage unit, a mains power supply unit, an energy management unit and a load, and the photovoltaic The power generation unit is connected to the DC bus through a one-way DC/DC rectification module, the mains power supply unit is connected to the DC bus through a one-way AC/DC rectification module, and the energy storage unit is connected to the DC bus through a two-way DC/DC conversion module , the energy management unit includes a main control module and an operation monitoring module that is arranged in each unit of the microgrid system and monitors the operating status of each unit, and the operation monitoring module is connected to the main control module and can The collected and analyzed data is uploaded to the main control module, and the main control module controls the photovoltaic power generation unit, energy storage unit and mains power supply unit to operate according to the set power supply logic and maintain the stability of the bus voltage according to the data. 2. A non-inverting solar-storage DC micro-grid system applied to modern buildings according to claim 1, wherein the energy storage unit includes a lead-acid battery. 3. A non-inverting solar-storage DC microgrid system applied to modern buildings according to claim 1, characterized in that: the load includes a DC load, and the DC bus can be directly connected to the DC load or through The unidirectional DC/DC conversion module is connected with the DC load. 4. A non-inverting solar-storage DC microgrid system applied to modern buildings according to claim 2, characterized in that: the load includes an AC load, and the DC bus passes through a unidirectional DC/AC conversion module connected to an AC load. 5. A non-inverting solar-storage DC micro-grid system applied to modern buildings according to claim 1, characterized in that: the energy management unit also includes a grounding state for the DC bus and each unit An insulation monitoring module for monitoring, the insulation monitoring module is communicatively connected with the main control module. 6. A non-inverting solar-storage DC micro-grid system applied to modern buildings according to claim 1, characterized in that: the rated voltage of the DC bus is 380V. 7. A non-inverting solar-storage DC micro-grid system applied to modern buildings according to claim 3, characterized in that: said DC loads include DC charging piles, DC inverter air conditioners, DC lighting, and DC power distribution interface, DC refrigerator. 8. A non-inverting solar-storage DC micro-grid system applied to modern buildings according to claim 4, wherein the AC loads include AC charging piles and AC distribution boxes.