CN201323453Y - Renewable energy micro-grid - Google Patents

Abstract

The utility model discloses a renewable energy micro-grid, which comprises a solar power generation unit, a wind power generation unit and a biogas power generation unit; The power output of the biogas power generation unit is calculated and adjusted by detecting the power output of the wind power generation unit and the solar power generation unit. The utility model adopts the scenery biogas, which is less affected by the weather, and can supply power around the clock, and controls the voltage and output power of the micro-grid by controlling the biogas power generation, has high power quality, does not depend on conventional energy sources, and has little environmental pollution .

Description

A Renewable Energy Microgrid

technical field

The invention belongs to the basic composition structure of a micro-grid, and relates to a combined system of power generation sources with different power generation properties in the micro-grid.

Background technique

Microgrid refers to a system that connects scattered power generation resources (such as self-powered power generation equipment or backup generator sets, solar power generation devices, wind power generation equipment, diesel power generation equipment, etc.) in a certain area. It can also run in parallel with the main large-scale power grid through the power distribution link.

The research on micro-grid has been greatly developed, such as the micro-grid with multi-energy complementary network architecture powered by wind turbines, photovoltaic cells and diesel engines (Renewable Energy, Volume: 9, Issue: 1-4, September 12 , pp.836-847, 1996.), fuel cell and micro-turbine hybrid power plant (IEEE Transactions on Energy Conversion, Vol.18, No.2, June 2003.), fan and diesel engine hybrid power plant (IEEE Transactions on Energy Conversion , Vol.13, No.3, September 1998.)

In the field of wind power generation and solar power generation, Chinese patent ZL88202956.8, wind power-photoelectric complementary device, combines the above two types of power generation devices into one, and shares a common controller.

At present, the power generation sources of micro-grid are generally renewable energy (such as wind power, solar energy, tidal energy, geothermal energy) and conventional energy (such as oil, coal). The development of such a micro-grid has such defects:

First of all, this type of micro-grid contains conventional energy, which will cause certain pollution to the environment, and with the continuous consumption of conventional energy, this type of micro-grid will continue to decrease.

Secondly, wind energy and light energy in renewable energy have the characteristics of low energy density, strong randomness, and instability. In the process of forming a micro-grid or connecting with a large power grid for energy conversion, it will inevitably affect the stability of the system, resulting in power loss. The efficiency of production, transmission and utilization is reduced, the service life of some equipment is shortened, and even failure or burning occurs.

Finally, if only wind and solar renewable energy is used to form a micro-grid, this type of grid is restricted by the weather and cannot provide continuous all-weather power supply, and the unit power cost is high.

Utility model content

The purpose of the utility model is to provide a renewable energy micro-grid with high power quality and relatively low cost aiming at the defects of the prior art.

Technical scheme of the present invention is:

A renewable energy micro-grid system is characterized in that it includes a solar power generation unit, a wind power generation unit and a biogas power generation unit; the solar power generation unit, the wind power generation unit and the biogas power generation unit are all connected to a DC bus and a system controller, and the system controller passes through The power output of the wind power generation unit and the solar power generation unit is detected to calculate and adjust the power output of the biogas power generation unit.

Further, it also includes a grid-connected inverter, which is connected to the DC bus and controlled by the system controller.

Further, it also includes a storage battery, which is connected to the DC bus through a DC-DC converter controlled by the system controller.

The utility model first determines the content of wind energy and solar energy in the area where the micro-grid is located, determines the capacity of solar energy and wind power generation according to the availability rate and unit power cost, and determines the power generation capacity of biogas (biomass energy) according to the load on this basis, thus forming wind-light-biogas microgrid.

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

First of all, this kind of renewable energy micro-grid has broad development prospects, it does not depend on conventional energy sources, and has little environmental pollution.

Secondly, this micro-grid uses wind-solar biogas, which is less affected by the weather and can supply power around the clock. Moreover, the voltage and output power of the micro-grid are controlled by controlling biogas power generation, which has high power quality.

Finally, the cost per unit power of this micro-grid is lower than that of the wind-solar micro-grid, and the power supply is stable.

Description of drawings

Fig. 1 is the schematic diagram of the utility model.

Detailed ways

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

As shown in Figure 1, a renewable energy micro-grid system includes a solar power generation unit, a wind power generation unit, and a biogas power generation unit; the solar power generation unit, the wind power generation unit, and the biogas power generation unit are all connected to the DC bus and the system controller, and the system The controller calculates and adjusts the power output of the biogas power generation unit by detecting the power output of the wind power generation unit and the solar power generation unit.

The wind turbine controller obtains the maximum output power by controlling the generator speed, and then controls the output voltage at 500v through the AC-DC converter. The power of the wind turbine unit is uncontrollable. The state quantities are sent to the system controller through the communication network.

The solar battery array controls the output voltage at 500v through the DC-DC converter, and the solar battery controller performs maximum power tracking control, and sends the instantaneous state quantities of voltage and current to the system controller through the communication network.

The internal combustion engine generator generates electricity by burning biogas, and then controls the output voltage at 500v through the AC/DC converter. The biogas generator controller performs constant speed control and variable power control, and sends the instantaneous state quantities of voltage and current to the system through the communication network controller.

The output voltages of the three power generation units are all matched with the DC bus voltage to 500v, and are connected together through the DC bus (two DC transmission lines) to form a micro-grid. At this time, when the wind power generation unit and the solar power generation unit are performing maximum power tracking control, their output power is a variable amount, and each power generation unit communicates with the system controller, and the system controller detects the solar power generation unit and the wind power generation unit. When the instantaneous state quantity is detected, the instantaneous state quantity of the load and the DC bus is detected at the same time, the output power of the biogas generating unit is calculated, and the power command is sent to the biogas generator controller. After receiving the command, the biogas generator controller performs power compensation control. This can ensure that the micro-grid maintains a constant voltage of 500v.

When the wind power generation unit and the solar power generation unit have no output, the two units can be disconnected, and the biogas power generation unit alone supplies power to the micro-grid.

When the bus voltage is greater than 500v, the battery absorbs energy from the grid to keep the DC bus voltage stable at 500v, and when the bus voltage is less than 500v, it outputs electric energy to the grid to keep the DC bus voltage stable at 500v.

When the power generated by the micro-grid is greater than the load required, and the biogas generating unit has power generation margin, the grid-connected inverter starts to work and outputs power to the large grid. When the maximum power generated by the micro-grid is less than the load required, the grid-connected inverter The inverter absorbs power from the mains grid.

Generally speaking, the physical distance between the power generation units of the microgrid is not very far, and the controllers of each power generation unit can be connected to the central controller through wired transmission to form an effective information transmission and control network.

Claims (3)

1. A renewable energy micro-grid is characterized in that it includes a solar power generation unit, a wind power generation unit and a biogas power generation unit; the solar power generation unit, the wind power generation unit and the biogas power generation unit are all connected to a DC bus and a system controller, and the system controller The power output of the biogas power generation unit is calculated and adjusted by detecting the power output of the wind power generation unit and the solar power generation unit. 2. The micro-grid according to claim 1, further comprising a grid-connected inverter connected to the DC bus and controlled by the system controller. 3. The micro-grid according to claim 2, further comprising a battery connected to the DC bus through a DC-DC converter controlled by the system controller.

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