CN203722320U - Double-bus excessively-miniature power grid system suitable for sustainable buildings - Google Patents

Abstract

Combined with the characteristics and needs of my country's buildings, a dual-bus DC pole micro-grid system including a cogeneration system suitable for sustainable buildings is proposed. The ultra-microgrid adopts a 380V and 48V dual busbar structure to combine new energy power generation, supercapacitor energy storage system, cogeneration system, load and control system to form an intelligent microgrid with less pollution, high energy utilization rate and flexible installation location. The power grid can work in two modes of islanding and grid-connected. High voltage (380V) is used to drive household high-power appliances with power factor correction circuits at the input end, because the intermediate voltage of these products is generally around 380V, which matches its industry standard, and can cancel the need for most household appliances to be connected to the AC grid. rectifier. The low voltage (48V) is the same as the telecom standard voltage, which can directly connect small electronic devices, improving their efficiency and safety. The energy storage system adopts a hybrid energy storage structure of supercapacitors and swappable electric vehicle batteries. At the same time, the system combines the house thermal energy system with the electric energy system through the combined heat and power system, hot water tank and electric heater to realize comprehensive management of energy. The microgrid can be connected to the AC grid through a bidirectional AC-DC (AC-DC) converter. Through reasonable design and coordinated control, the proposed DC microgrid system can improve the power quality of sustainable buildings; combine thermal and electrical systems to improve energy utilization efficiency; realize the effective utilization of distributed new energy and the functions of energy saving and emission reduction.

Description

A dual-bus DC pole microgrid system for sustainable buildings

technical field

The utility model relates to a power supply system in which a direct current extremely micro grid system of a power system is combined with a cogeneration system of heat and power. In particular, it refers to a DC micro-grid power supply system with high energy utilization rate that contains a double busbar structure for sustainable buildings, and combines the house electrical energy system with the thermal energy system.

Background technique

With the rapid development of economy, energy crisis and environmental pollution have become serious problems facing the world today. Sustainable buildings can achieve "zero energy consumption" in buildings, use new energy to generate electricity, reduce the consumption of limited fossil fuels, reduce air pollution, achieve energy conservation and emission reduction, and sustainable urban development. It is a residential type that will be vigorously developed in future cities.

At present, the known sustainable buildings use thermal insulation materials as walls, use LED lighting and other methods to improve energy saving; use distributed renewable energy to generate electricity to provide electricity. However, compared with micro-grids, distributed renewable energy generation has low energy utilization rate, decentralized control structure, and complex user operations. General sustainable residential electricity and thermal energy systems are managed separately, which cannot maximize the use of energy.

The utility model adopts a very micro-grid to combine renewable energy, an energy storage system, and a cogeneration system to form a smart micro-grid with less pollution, high energy utilization rate, and flexible installation location, which saves power transmission and distribution resources and operating costs , reducing the line loss of centralized transmission, reducing the total capacity of the grid, improving the peak and valley performance of the grid, and increasing reliability. At the same time, the system combines the house thermal energy system with the electric energy system through the combined heat and power system, hot water tank and electric heater to realize comprehensive management of energy.

Among them, the DC microgrid form is adopted, which has no skin effect, low loss, high efficiency, no reactive power compensation, no inherent stability problems of the AC power supply system, and the transmission distance and power are not affected by the stability of the synchronous operation of the power system. advantages such as limitations and ease of control. The double busbar structure is adopted to meet the voltage level requirements of different electrical appliances and reduce the power loss of the intermediate converter link.

Contents of the invention

In order to realize high-efficiency utilization of distributed energy, solve the problem of "zero energy consumption" in sustainable buildings, and provide users with convenient and economical power energy, the utility model proposes a DC extremely micro-grid system that conforms to the characteristics of modern buildings. The system uses a 380V and 48V dual busbar structure to combine distributed energy generation, energy storage system, cogeneration system, load and control system, making the residential power grid a controllable load of the large power grid, which can work in isolated islands and in parallel. There are two working modes of the network. The energy storage system adopts a hybrid energy storage structure of supercapacitors and swappable electric vehicle batteries. At the same time, the system combines the house thermal energy system with the electric energy system through the combined heat and power system, hot water tank and electric heater to achieve comprehensive energy management.

The technical scheme that the utility model adopts is:

Combining bidirectional AC-DC converters, distributed power sources, hybrid energy storage systems including supercapacitors and electric vehicle batteries, combined heat and power systems, and loads through DC buses to form dual buses in sustainable buildings DC extremely microgrid improves power quality through microgrid control.

The microgrid can be connected to the AC grid in parallel through a bidirectional AC-DC (AC-DC) converter. A bidirectional alternating current-direct current (AC-DC) converter can be either a voltage source converter or a current source converter. If the bidirectional AC-DC (AC-DC) converter adopts pulse width modulation (PWM) control, it can reduce system harmonics and improve the power factor of the system.

A cogeneration system of heat and power is installed in each apartment, and the system is connected to the DC bus through a DC-DC converter. The combined heat and power system can not only provide electricity, but also provide domestic water or HVAC water for users. At the same time, the system combines the house thermal energy system with the electric energy system through the combined heat and power system, hot water tank and electric heater to realize comprehensive management of energy.

The hybrid energy storage system consists of a supercapacitor and a swappable electric vehicle battery, which are connected to the DC bus through a bidirectional direct current-direct current (DC-DC) converter. When there is excess power in the microgrid system, the DC bus voltage rises to reach the defined voltage threshold, and the hybrid energy storage system absorbs the excess power and charges the power battery of the electric vehicle through the charging and discharging machine. The AC-DC (AC-DC) converter (inverter at this time) feeds back to the AC grid to prevent the DC bus voltage from exceeding the limit value; when the power of the micro grid system is insufficient, the DC bus voltage is reduced to the limited voltage Threshold, the bidirectional AC-DC (AC-DC) converter (rectifier at this time) converts AC power into DC power to supply power to the DC bus, and the hybrid energy storage system discharges power to the DC bus to prevent the DC bus voltage from falling below the limit value , to maintain the power balance of the system.

If the capacity of the distributed power supply and energy storage system is large enough, the microgrid can not only operate in the grid-connected state, but also in the off-grid (or island) state. When the AC power supply system fails, it can operate in an off-grid (or island) state, and the house is powered by the distributed power supply and energy storage system.

The extremely microgrid adopts a 380V and 48V double busbar structure. High voltage (380V) is used to drive household high-power electrical appliances with power factor correction circuits at the input end, because the intermediate voltage of these products is generally around 380V, which matches its industry standard, and can cancel the need for most household appliances to be connected to the AC power grid. rectifier. The low voltage (48V) is the same as the telecom standard voltage, which can directly connect small electronic devices, improving their efficiency and safety.

The converters in the system can be controlled by either master-slave control, peer-to-peer control or droop control, or layered control. The control command in the system can be given by the control center through the communication system, or it can be given according to the voltage and current of the system.

Compared with the prior art, the utility model has the advantages of:

In sustainable buildings, DC microgrids are used to combine distributed energy generation, energy storage systems, combined heat and power systems, loads and control systems to realize the effective use of distributed new energy and improve the quality of power supply; proposed The double-bus DC pole micro-grid structure meets the voltage level requirements of different electrical appliances and reduces the loss of electric energy in the intermediate converter link; the combined heat and power system is used to improve energy utilization efficiency and provide domestic water for users at the same time; through the combined heat and power system , hot water tanks and electric heaters combine the house thermal energy system with the electric energy system to achieve comprehensive energy management; the hybrid energy storage system based on supercapacitors and swappable electric vehicle batteries realizes energy recovery and reduces the DC bus voltage fluctuations; if the capacity of the distributed power generation and energy storage system is large enough, the system can operate in an island, thereby improving the reliability of power supply for sustainable houses.

Description of drawings

Figure 1 is a structural diagram of a dual-bus DC pole microgrid system including a combined heat and power system.

Figure 2 is a block diagram of the hybrid energy storage system.

Figure 3 is a diagram of the combined heat and power system.

specific implementation plan

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

Referring to accompanying drawing 1, what the utility model patent discloses is a dual-bus DC pole micro-grid system suitable for sustainable buildings including heat and power cogeneration systems. The system uses a 380V and 48V dual busbar structure to combine photovoltaic power generation, supercapacitor energy storage system, cogeneration system, load and control system. The grid-connected converter uses a bidirectional alternating current-direct current (AC-DC) converter to realize the bidirectional flow of power. Each room is equipped with a combined heat and power system, which not only provides users with electricity, but also provides domestic water to improve energy efficiency. Clean energy (solar, wind) power generation supplies power to the 380V bus through a one-way converter. The double-busbar structure is convenient for power supply of various loads, and the high voltage (380V) is used to drive household high-power appliances with power factor correction circuits at the input. The low voltage (48V) is the same as the telecom standard voltage, which can directly connect small electronic devices, improving their efficiency and safety.

Referring to Figure 2, in order to stabilize the voltage of the DC bus, a hybrid energy storage system that can quickly and bidirectionally interact with the DC bus is composed of a supercapacitor and a swappable electric vehicle battery. When there is excess power in the microgrid system, the DC bus voltage rises to reach the defined voltage threshold, and the hybrid energy storage system absorbs the excess power and charges the power battery of the electric vehicle through the charging and discharging machine. The AC-DC (AC-DC) converter (inverter at this time) feeds back to the AC grid to prevent the DC bus voltage from exceeding the limit value; when the power of the micro grid system is insufficient, the DC bus voltage is reduced to the limited voltage Threshold, the bidirectional AC-DC (AC-DC) converter (rectifier at this time) converts AC power into DC power to supply power to the DC bus, and the hybrid energy storage system discharges power to the DC bus to prevent the DC bus voltage from falling below the limit value , to maintain the power balance of the system.

Referring to Figure 3, in order to improve the system efficiency, facilitate the hot water supply for users, and combine the house thermal energy system with the electric energy system to realize comprehensive energy management, each house is equipped with a combined heat and power system. The electric heater can control the temperature of the water tank, absorb peak power, and protect the energy storage system in the event of a fault such as a full battery. The electric heater can be equipped with manual switch and automatic switch. The reference value of the automatic switch should include battery power, water temperature, and power exchange with the large power grid. The smooth transition of the switch can be realized according to the reference value. The manual switch can facilitate other needs of users.

Claims (4)

1. A dual-bus DC pole micro-grid system suitable for sustainable buildings. Distributed energy generation, energy storage systems, and loads are connected through DC buses. It is characterized by: a combined heat and power system, a hot water tank and an electric heater. The thermal energy system is connected to the ultra-micro-grid, which uses 380V and 48V high and low-voltage dual busbars, super capacitors and battery swapping electric vehicle batteries to form a hybrid energy storage system. the 2. The dual-bus DC pole micro-grid system suitable for sustainable buildings according to claim 1 is characterized in that 380V and 48V high and low voltage dual buses are used, and the 380V DC bus is connected to cogeneration systems and distributed energy generation , energy storage system, high-power load, 48V DC bus connected to low-power load. the 3. The dual-bus DC pole micro-grid system suitable for sustainable buildings according to claim 1, characterized in that the combined heat and power system is connected with the DC bus and the hot water tank, the electric heater is connected with the hot water tank, and the electric heating The controller is set with a manual switch and an automatic switch. The reference value of the automatic switch includes the energy storage system power, water temperature, and the power exchange value with the large power grid. the 4. The double-bus DC pole micro-grid system suitable for sustainable buildings according to claim 1, characterized in that the hybrid energy storage system is composed of supercapacitors and electric vehicle batteries, and the hybrid energy storage system passes bidirectional DC- A direct current (DC-DC) converter is connected to the DC bus. the