CN201956701U - Single house type AC (Alternating Current)/DC (Direct Current) mixing microgrid - Google Patents

Description

A single-family AC-DC hybrid microgrid

technical field

The utility model relates to a single-family AC-DC hybrid microgrid, specifically a hybrid microgrid comprising photovoltaic power generation units, wind power generation units, energy storage units, electric vehicle DC charging piles, DC loads and AC loads.

Background technique

For the current AC-DC hybrid microgrid, a special DC/AC switching module is generally designed to connect to the DC bus for the power supply of AC loads. This kind of solution is that the DC/AC switching module has power loss, and the second is the increased construction cost; at the same time, the existing AC-DC hybrid micro-grid does not consider the use of energy storage and distributed power generation to provide charging energy for electric vehicle DC charging piles. .

Contents of the invention

The purpose of this utility model is to overcome the above-mentioned shortcomings existing in the existing AC-DC hybrid micro-grid, and to provide an AC-DC hybrid micro-grid system, which can effectively reduce the construction cost and operation cost of the micro-grid, and adopt photovoltaic power generation, wind power generation , the energy storage unit and the large power grid jointly charge the electric vehicle with DC, thereby reducing the impact on the power grid when the electric vehicle is charging.

The purpose of this utility model is achieved through the following technical solutions:

A single-family AC-DC hybrid microgrid consists of an AC/DC bidirectional converter, three unidirectional DC/DC converters, and two bidirectional DC/DC converters connected in parallel by means of a DC bus; the unidirectional The DC/DC converter and the bidirectional DC/DC converter are also connected in series, and the arrangement is two unidirectional DC/DC converters, two bidirectional DC/DC converters, and one unidirectional DC/DC converter; The first unidirectional DC/DC converter is connected to a photovoltaic power generation unit, and the second unidirectional DC/DC converter is connected to a DC/AC switching module, and the DC/AC switching module is connected to a wind power generation unit; The third bidirectional DC/DC converter is connected to an energy storage unit, the fourth bidirectional DC/DC converter is connected to an electric vehicle DC charging pile, and the fifth unidirectional DC/DC converter is connected to a DC load; AC/ The DC bidirectional converter is also connected in series with the microgrid switch to connect to the large power grid, and the AC load is connected to the side of the microgrid switch close to the AC/DC bidirectional converter; the microgrid controller connected with the touch screen is connected to the microgrid switch The switch is connected in parallel with the AC/DC bidirectional converter.

The micro-grid controller of the utility model adopts the hardware platform of 32-bit MCU+DSP processor, and the micro-grid controller is respectively provided with an analog input unit, a frequency unit, a bus controller, an RS485 port, a switching value input unit, and a switching value output unit ; Wherein the switch value output unit is respectively connected with the grid-connected switch of the micro-grid and the contactor of the charging pile.

The micro-grid controller of the utility model is connected to the touch display screen, AC/DC bidirectional converter, all unidirectional DC/DC converters, all bidirectional DC/DC converters are connected, and unidirectional DC/DC converter is connected through RS485 communication mode. device.

In the utility model, when the micro-grid is connected to the grid, the user's AC load is powered by the large power grid, and the micro-grid controller controls the photovoltaic unit and the wind power generation unit to charge the energy storage unit; when the isolated grid is running, the micro-grid controller controls the switching of the micro-grid The switching action disconnects the connection with the large power grid, and the AC/DC bidirectional converter is reused, and the inverter generates AC power to supply power to the load. When charging the electric vehicle, the micro-grid controller coordinates and controls the photovoltaic unit, wind power generation unit, and energy storage unit to provide electric energy to the DC charging pile of the electric vehicle. The DC power load is powered by the DC bus through DC/DC voltage regulation.

The beneficial effect of the utility model is that the AC/DC conversion module is reused, and the construction cost and operation loss of the AC/DC hybrid micro-grid are reduced; photovoltaic power generation, wind power generation, energy storage unit and large power grid are used to jointly charge electric vehicles in DC , so as to reduce the impact of electric vehicles on the grid when charging, and also reduce the capacity of the equipment connected to the grid.

Further elaborate the content of the utility model below in conjunction with accompanying drawing and embodiment.

Description of drawings

Figure 1 is a structural block diagram of the AC-DC hybrid microgrid;

Fig. 2 is a block diagram of a unidirectional DC/DC converter circuit;

Fig. 3 is a structural block diagram of a bidirectional DC/DC converter;

Fig. 4 is a structural block diagram of the AC/DC converter circuit;

Figure 5 is a block diagram of the circuit structure of the microgrid controller.

Detailed ways

The utility model is composed of an AC/DC bidirectional converter, three unidirectional DC/DC converters, and two bidirectional DC/DC converters, which are connected in parallel in the form of a DC bus; the unidirectional DC/DC converter and the bidirectional The DC/DC converters are also connected in series, and the arrangement is two unidirectional DC/DC converters, two bidirectional DC/DC converters, and one unidirectional DC/DC converter; the unidirectional DC/DC converter ranked first The DC converter is connected to a photovoltaic power generation unit, and the second-ranked unidirectional DC/DC converter is connected to a DC/AC switching module, and the DC/AC switching module is connected to a wind power generation unit; the third-ranked bidirectional DC/DC converter The energy storage unit is connected to the power converter, the fourth-ranked bidirectional DC/DC converter is connected to the DC charging pile of electric vehicles, and the fifth-ranked unidirectional DC/DC converter is connected to a DC load; the AC/DC bidirectional converter is also connected to the The micro-grid switch is connected in series to the large power grid, and the AC load is connected to the side of the micro-grid switch close to the AC/DC bidirectional converter; the micro-grid controller with a touch screen is connected to the micro-grid switch and the AC/DC bidirectional converter Flowmeters are connected in parallel.

The micro-grid controller of the utility model adopts the hardware platform of 32-bit MCU+DSP processor, and the micro-grid controller is respectively provided with an analog input unit, a frequency unit, a bus controller, an RS485 port, a switching value input unit, and a switching value output unit ; Wherein the switch value output unit is respectively connected with the grid-connected switch of the micro-grid and the contactor of the charging pile.

The micro-grid controller of the utility model is connected to the touch display screen, AC/DC bidirectional converter, all unidirectional DC/DC converters, all bidirectional DC/DC converters are connected, and unidirectional DC/DC converter is connected through RS485 communication mode. device.

As shown in Fig. 1, Fig. 2, Fig. 3, and Fig. 4, the utility model is composed of AC/DC bidirectional converters, three unidirectional DC/DC converters, and two bidirectional DC/DC converters connected in parallel in the form of a DC bus. The AC/DC bidirectional converter is also connected to the large power grid in series with the micro-grid switch, and the AC load is connected to the side of the micro-grid switch close to the AC/DC bidirectional converter; one of the unidirectional DC/DC converters is also A photovoltaic unit is connected, another unidirectional DC/DC converter is connected with a DC/AC switching module, and the DC/AC switching module is connected with a wind power generation unit; a bidirectional DC/DC converter is connected with an energy storage unit, and a bidirectional DC The /DC converter is connected to the DC charging pile of the electric vehicle; the unidirectional DC/DC converter is connected to the DC load.

The micro-grid controller of the utility model adopts a high-performance 32-bit MCU+DSP processor hardware platform, and the micro-grid controller is provided with an AC analog input unit, a frequency acquisition unit, a switch input unit, a switch output unit, and a communication interface unit 1. A display unit; the switch output unit of the micro-grid controller is connected to the control loop of the micro-grid switch.

The micro-grid controller of the utility model is connected to the touch display screen, AC/DC bidirectional converter, all unidirectional DC/DC converters, all bidirectional DC/DC converters are connected, and unidirectional DC/DC converter is connected through RS485 communication mode. device.

The micro-grid switching switch in the present invention is an automatic control switch, and the micro-grid controller controls its opening and closing operation through the switching value output unit, so as to realize the grid-connection or disconnection of the micro-grid and the large power grid; AC/DC bidirectional converter The circuit structure diagram of the system is shown in Figure 4, which realizes bidirectional power flow; the unidirectional DC/DC converter of the photovoltaic power generation unit and the wind power generation unit adopts a Boost conversion circuit and has a maximum power point tracking (MPPT) control function, as shown in Figure 2 The energy storage unit adopts a bidirectional DC/DC conversion circuit, as shown in Figure 3.

When the micro-grid is connected to the grid, the micro-grid controller issues an instruction to close the micro-grid switch, and the user's AC load is supplied by the large power grid; the electric energy generated by the photovoltaic power generation unit and the wind power generation unit is coordinated by the micro-grid controller. Charge the energy storage unit to the DC/DC converter and the bidirectional DC/DC converter; when the energy storage unit is full or fails, the charging stops. If the power generation in the microgrid is greater than the load, the excess power in the microgrid is sent to the grid by the AC/DC converter. When the microgrid is connected to the grid, the control goal of the AC/DC bidirectional converter is to maintain the DC bus voltage of the microgrid at the target value.

When the isolated grid is running, the microgrid controller controls the switching action of the microgrid, disconnects the connection with the large power grid, and supplies power to the DC load in the microgrid from the photovoltaic power generation unit, wind power generation unit and energy storage unit, and the AC load is supplied by the AC/ The DC bidirectional converter inverts to generate AC power supply. At this time, the DC voltage of the microgrid is maintained at the target value by the bidirectional DC/DC converter of the energy storage unit.

When charging electric vehicles, the microgrid is required to run in a grid-connected state. Under the coordinated control of the micro-grid controller, the electric energy required by the electric vehicle enables the photovoltaic power generation unit, wind power generation unit, and energy storage unit to provide electric energy to the electric vehicle DC charging pile through communication, and the insufficient electric energy is provided by AC/ The DC bidirectional converter is obtained from the grid side.

The DC power load obtains power from the DC bus through unidirectional DC/DC voltage regulation. This unidirectional DC/DC converter adopts a Buck step-down circuit.

In Fig. 5, the micro-grid controller adopts the hardware platform of high-performance 32-bit MCU+DSP processor, and collects the AC/DC bidirectional converter, unidirectional DC/DC converter, and bidirectional DC/DC converter through RS485 communication. Status and information; collect the running status of the energy storage device through the digital input unit; collect the voltage and current value of the energy storage unit through the analog input channel; at the same time, the analog communication also collects the voltage and current of the grid, and the grid voltage is obtained through calculation The amplitude, phase, and equivalent impedance of the grid are combined with the grid frequency value obtained by the frequency acquisition unit to determine whether there is a fault/power outage in the grid; the switch value output unit controls the opening and closing of the micro-grid grid-connected switch, and the DC charging of electric vehicles The opening and closing of the pile DC contactor; the MCU unit is connected with the RS485 interface circuit, LCD, LED and buttons, which can accept the input information of the man-machine interface, and drive the LED to display the status of the micro-grid controller; the DSP communicates with the external controller through the bus controller. The storage is connected to the Ethernet interface.

The unidirectional DC/DC converter, bidirectional DC/DC converter and AC/DC converter of the utility model all adopt general technology, and their products can be customized from relevant manufacturers; the micro-grid switching switch and the DC charging pile of electric vehicles are mature product .

Claims (2)

1. A single-family AC-DC hybrid microgrid, characterized in that it consists of an AC/DC bidirectional converter, three unidirectional DC/DC converters, two bidirectional DC/DC converters, and adopts a DC bus Composed of parallel connections; the unidirectional DC/DC converter and the bidirectional DC/DC converter are also connected in series, and the arrangement is two unidirectional DC/DC converters, two bidirectional DC/DC converters, and a unidirectional DC /DC converter; the unidirectional DC/DC converter ranked first is connected to a photovoltaic power generation unit, the unidirectional DC/DC converter ranked second is connected to a DC/AC switching module, and the DC/AC switching module is connected to a wind power Power generation unit; the third ranked bidirectional DC/DC converter is connected to an energy storage unit, the fourth ranked bidirectional DC/DC converter is connected to an electric vehicle DC charging pile, and the fifth ranked unidirectional DC/DC converter is connected to There is a DC load; the AC/DC bidirectional converter is also connected to the large power grid in series with the micro-grid switch, and the AC load is connected to the side of the micro-grid switch close to the AC/DC bidirectional converter; connected to the micro-grid with a touch screen The controller is connected in parallel with the microgrid switch and the AC/DC bidirectional converter. 2. A single-family AC-DC hybrid micro-grid according to claim 1, wherein the micro-grid controller adopts a hardware platform of 32-bit MCU+DSP processor, and the micro-grid controller is respectively provided with an analog input unit , frequency unit, bus controller, RS485 port, switch input unit, and switch output unit; where the switch output unit is connected to the micro-grid grid-connected switch and the charging pile contactor respectively.

Images