CN103904680B - Power supply equipment, power generation unit and power generation system - Google Patents

Abstract

The present invention relates to a power supply device, a power generation unit and a power generation system, wherein the power supply device includes: a power generation unit driver for converting direct current into alternating current or converting alternating current into direct current; The AC power converted by the unit driver converts the AC power converted by the power generation unit driver into mechanical energy; the synchronous generator is used to generate AC power according to the mechanical energy converted by the AC motor and output it to the public connection point; connected to the power generation unit a first switch between the driver and the AC motor; and a bypass switch, one end of which is connected between the power generation unit driver and the first switch, and the other end is connected between the synchronous generator and a common connection point between. With the power supply equipment, power generation unit and power generation system, the AC-driven power generation unit can work in multiple modes, so that it can Control the operation mode of the power generation unit to achieve more efficient and stable operation.

Description

Power supply equipment, power generation unit and power generation system

technical field

The invention relates to a power system, in particular to a power supply device, a power generation unit and a power generation system.

Background technique

At present, a microgrid can refer to a small power generation, distribution, and consumption system composed of one or more parts such as distributed power generation units, energy conversion devices, monitoring devices, protection devices, and related loads. The so-called small is smaller than the scale of the main power grid. The microgrid can run in parallel/parallel/grid-connected with the external power grid (such as the main power grid, etc.), or it can run independently. Generally speaking, a microgrid is an autonomous system capable of self-control, self-protection, and self-management.

The power generation units in the microgrid generally have multiple types such as the first energy generation unit and the second energy generation unit. The first energy generating unit is driven by such as renewable energy, and the first energy generating unit can be embodied as an intermittent renewable energy generating unit, which is driven by intermittent renewable energy such as photovoltaic (photovoltaic, PV), wind, tide, etc.; The second energy generation unit is driven by traditional energy such as coal, gas, diesel, and small hydropower. Specifically, the intermittent renewable energy power generation unit is composed of energy capture equipment and power electronic energy conversion equipment, and is connected to the microgrid as a grid-connected unit. Power electronic energy conversion equipment can be a converter (converter) or an inverter (inverter), etc. The converter is used to perform general power conversion, such as AC (Alternating Current, AC) input, DC (Direct Current, DC) output (ie AC /DC), DC/AC, DC/DC, AC/AC, etc., the inverter is mainly used to realize DC/AC conversion. Since intermittent renewable energy has the characteristics of low energy density, strong influence by weather and environmental conditions, strong output power fluctuation, and difficult to predict accurately, the total installed capacity of intermittent renewable energy power generation units in microgrids is usually subject to large constraints. limit. If this limit is exceeded, the safe and stable operation of the microgrid cannot be guaranteed, and it may also bring unfavorable factors to the stability of the external grid connected to it.

The conventional method of connecting intermittent renewable energy power generation units to the microgrid is shown in Figure 1. Traditional energy generating units (such as small hydropower, diesel power generation, etc.) are used to establish and stabilize the voltage and frequency of the microgrid, while intermittent renewable energy Energy, as a grid-connected unit, is connected to the microgrid by means of current source control. Specifically, FIG. 1 includes the following parts: an external power grid 11 and a microgrid 12 . The external grid 11 may be a main grid or another microgrid different from the microgrid 12 . The microgrid 12 includes: one or more photovoltaic branches PV1 . . . PVn, one or more wind power branches, diesel or hydroelectric generators 106 , loads 107 and switches 108 . The photovoltaic branch, the wind branch, the diesel or hydroelectric generator 106, and the load 107 are all connected to a point of common coupling (PCC). Specifically, the PCC may be an AC bus. Each photovoltaic branch includes: a PV array 101 , a DC/AC inverter 102 ; each wind power branch includes: a wind generator 103 , an AC/DC converter 104 , and a DC/AC inverter 105 . In this mode, in order to ensure the reliable and stable operation of the microgrid, it is necessary to configure a large-capacity traditional power supply to maintain the voltage and frequency of the microgrid stable. At this time, the intermittent renewable energy power generation unit does not participate in the regulation of the voltage and frequency of the microgrid, and its proportion of total power generation capacity is greatly restricted in the microgrid.

Chinese patent application CN102244498A proposes an AC-driven power generation unit in a grid, which can contribute to the stability of grid power supply when using intermittent renewable energy. As shown in FIG. 2 , in this patent application, an AC-driven power generation unit 200 includes an energy input module 210 , an energy storage module 220 and an energy output module 230 . The energy input module 210 can utilize intermittent renewable energy sources such as photovoltaics, wind power, and tides, and output relatively stable DC power through corresponding power electronic controllers. The energy input module 210 may include an energy capture device 212 for capturing one or more intermittent renewable energy sources and a charge controller 214 . The energy storage module 220 can be used to store the direct current output by the energy input module 210 . The energy output module 230 includes a power generation unit driver (SPU driver) 232 , an AC motor 234 , and a synchronous generator (synchronous generator, SG) 236 . Wherein, the power generation unit driver 232 is used to convert the direct current from the energy input module 210 and/or the energy storage module 220 into alternating current. The AC motor 234 is used to convert the AC power from the generating unit driver 232 into mechanical energy, and the synchronous generator 236 is used to convert the mechanical energy from the AC motor 234 into electrical energy, and its rotor and the rotating magnetic field formed by the stator maintain synchronous speed. However, the AC-driven generating unit can only work in a grid-stabilizing mode.

Contents of the invention

In view of this, an embodiment of the present invention provides a power supply device, a power generation unit and a power generation system, which can make the power generation unit work in multiple modes.

A power supply device according to an embodiment of the present invention includes: a power generating unit driver, used to convert direct current into alternating current or convert alternating current into direct current; an alternating current motor, used to convert the alternating current converted by the power generating unit driver into mechanical energy; synchronous a generator for converting the mechanical energy into AC electrical energy and outputting it to a common connection point; a first switch connected between the generating unit driver and the AC motor; and a bypass switch connected at one end of the between the power generation unit driver and the first switch, and the other end is connected between the synchronous generator and the common connection point.

In a specific implementation manner, the bypass switch and the first switch are configured such that: when the bypass switch is open, the first switch is closed, and when the bypass switch is closed, the The first switch is off.

In a specific implementation manner, the power supply equipment further includes a second switch connected between the synchronous generator and the common connection point, wherein the other end of the bypass switch is connected to the between the second switch and the common junction.

In a specific implementation manner, the bypass switch, the first switch and the second switch are configured to: when the bypass switch is open, the first switch and the second switch are closed , and the first switch and the second switch are open when the bypass switch is closed.

In a specific implementation manner, when the bypass switch is open and the first switch and the second switch are closed, the power generation unit driver converts direct current into alternating current and outputs it to the alternating current motor, and, When the bypass switch is closed and the first switch and the second switch are opened, the power generation unit driver converts the direct current into alternating current and outputs it to the common connection point through the bypass switch, or AC power from the point of common connection via the bypass switch is converted to DC power.

In a specific implementation manner, the bypass switch is one of the following: a mechanical contact type contactor, a mechanical contact type circuit breaker, a bidirectional switch formed by two power semiconductor switching devices in reverse series, and A bidirectional switch formed by parallel connection of a power semiconductor switching device and a rectifier bridge.

In a specific implementation manner, the first switch is a switch implemented by software in the driver of the power generation unit.

A power generation unit according to an embodiment of the present invention includes: an energy input module configured to capture energy and output direct current converted from the captured energy; an energy storage module configured to store the direct current output by the energy input module; and, The power supply device, together with the energy input module, the energy storage module and a common connection point, is used to convert the direct current from the energy input module and/or the energy storage module into alternating current and output it to the public connection point, or convert the alternating current from the public connection point into direct current and store it in the energy storage module.

In a specific implementation manner, the energy source includes at least one of the following: intermittent energy source, renewable energy source, and intermittent renewable energy source.

A power generation system according to an embodiment of the present invention includes: a plurality of the power generation units, wherein the plurality of power generation units are connected to a common connection point in parallel.

In a specific implementation manner, the plurality of power generation units share the same energy input module and energy storage module.

In a specific implementation manner, the multiple power generation units share the same energy storage module.

As can be seen from the above description, due to the addition of a bypass switch in the power supply equipment of the power generation unit, compared with the prior art, the power generation unit of the embodiment of the present invention can work in multiple modes, so that it can The connected grid or load conditions, the power generation environment conditions, and the conditions of the power generation unit itself flexibly control the operation mode of the power generation unit to achieve more efficient and stable operation.

Description of drawings

Other features, characteristics, advantages and benefits of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. in:

Fig. 1 shows a conventional microgrid topology structure diagram;

Fig. 2 shows the structural diagram of the power generation unit in the existing power system;

Figure 3 shows a schematic diagram of a power generating unit according to an embodiment of the present invention;

Figure 4A shows a schematic diagram of a bypass switch according to one embodiment of the present invention;

FIG. 4B shows a schematic diagram of a bypass switch according to another embodiment of the present invention;

Fig. 4C shows a schematic diagram of a bypass switch according to yet another embodiment of the present invention;

Fig. 4D shows a schematic diagram of a bypass switch according to yet another embodiment of the present invention;

Figure 5 shows a schematic diagram of a power generation system according to an embodiment of the present invention;

Figure 6A shows a schematic diagram of a power generation system according to another embodiment of the present invention; and

Fig. 6B shows a schematic diagram of a power generation system according to yet another embodiment of the present invention.

detailed description

In the following, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 3 shows a schematic diagram of a power generation unit according to an embodiment of the present invention. The power generation unit 300 shown in FIG. 3 is AC driven, and it can convert energy such as intermittent energy, renewable energy, or intermittent renewable energy into alternating current and output it to the grid and/or a public connection to which the load can be connected. point. Wherein, the power grid may be a microgrid or a backbone power grid, and the energy source may be, for example, photovoltaic power, wind power, tidal power, and the like. As shown in FIG. 3 , the power generation unit 300 may include an energy input module 310 , an energy storage module 320 and a power supply device 330 .

The energy input module 310 may be used to capture one or more energy sources and output electrical energy converted from the captured energy sources. Here, the energy input module 310 may include, for example, an energy capture device 312 and a charge controller 314 . Energy capture devices 312 may be used to capture and convert energy into electrical energy, and energy capture devices 312 may include, for example, photovoltaic (PV) arrays, wind generators, and the like. The charging controller 314 may be a DC/DC converter or an AC/DC converter for converting the electrical energy converted by the energy capture device 312 into direct current and storing it in the energy storage module 320 .

The energy storage module 320 , which can be connected to the energy input module 310 , is used for storing the direct current output by the energy input module 310 . Here, the energy storage module 320 may be a lead-acid battery, a lithium battery, a nickel-metal hydride battery or various other forms of energy storage.

A power supply device 330, which can be connected with the energy input module 310, the energy storage module 320 and the public connection point, for converting the direct current from the energy input module 310 and/or the energy storage module 320 into alternating current and outputting it to the public connection point, or The alternating current from the point of public connection is converted to direct current and stored in the energy storage module 320 . The power supply device 330 may include a power generation unit driver (SPU driver) 331 , an AC motor 332 , a synchronous generator 333 , a switch 334 , a switch 335 and a bypass switch 336 .

The power generation unit driver 331 is connected to the energy input module 310 and the energy storage module 320, and can work in DC/AC inverter mode to convert direct current to alternating current or can work in AC/DC rectification mode to convert alternating current to direct current. Wherein, when working in DC/AC inverter mode, the power generation unit driver 331 can convert the DC power of the energy input module 310 and/or the energy storage module 320 into AC power, wherein the converted AC power can be adjustable in frequency. Alternatively, when working in the AC/DC rectification mode, the power generation unit driver 331 may convert the received AC power into DC power and store it in the energy storage module 320 .

The AC motor 332 is connected to the power generation unit driver 331 and used for converting the AC power converted by the power generation unit driver 331 into mechanical energy if receiving the AC power converted by the power generation unit driver 331 .

The synchronous generator 333 is connected with the AC motor 332 and the public connection point, and is used to convert the mechanical energy generated by the AC motor 332 into AC electric energy and output it to the public connection point.

The switch 334 is connected between the power generation unit driver 331 and the AC motor 332, and the switch 335 is connected between the synchronous generator 333 and the common connection point.

One end of the bypass switch 336 is connected between the power generation unit driver 331 and the first switch 334, and the other end is connected between the switch 335 and the common connection point. The function of the bypass switch 336 is to realize the bidirectional flow of electric energy, therefore, any device capable of providing bidirectional electric energy passing can be used as the bypass switch 336 .

For example, bypass switch 336 may be a mechanical contact type contactor or circuit breaker. Alternatively, bypass switch 336 may be a triac, as shown in FIG. 4A. Alternatively, the bypass switch 336 may be a bidirectional switch formed by two power semiconductor switching devices in reverse series, such as the bidirectional switch formed by two IGBTs in reverse series in a common emitter manner as shown in FIG. The bidirectional switch shown is formed by two IGBTs connected in reverse series with common collectors. Alternatively, the bypass switch 336 may be a bidirectional switch formed by connecting a power semiconductor switching device in parallel with a rectifier bridge, such as the bidirectional switch formed by connecting an IGBT in parallel with a rectifier bridge as shown in FIG. 4D .

The switch 334 may be a switch realized by hardware, or may be a switch realized by software in the power generation unit driver 331 . The switch 335 shown in the figure is a switch implemented by hardware.

In power generation unit 300, bypass switch 336, switch 334, and switch 335 may be configured such that switch 334 and switch 335 are closed when bypass switch 336 is open, and switch 334 and switch 335 are open when bypass switch 336 is closed. open.

The operation mode of the power generation unit 300 is described below.

If the bypass switch 336 is open and the switch 334 and the switch 335 are closed, the power generation unit driver 331 works in the DC/AC inverter mode to convert the direct current of the energy input module 310 and/or the energy storage module 320 into alternating current, and the alternating current motor 332 converts the AC power converted by the power generation unit driver 331 into mechanical energy, and the synchronous generator 333 generates AC power under the action of the mechanical energy converted by the AC motor 332 and outputs it to the common connection point. When the power generation unit 300 works in this mode, it can stably supply power to the public connection point, thereby stabilizing the grid connected to the public connection point.

If the bypass switch 336 is closed and the switches 334 and 335 are open, the power generation unit 300 has two different operating modes depending on whether the power generation unit driver 331 is operating in DC/AC conversion mode or in AC/DC conversion mode.

If the power generation unit driver 331 works in the DC/AC conversion mode, the power generation unit driver 331 converts the DC power of the energy input module 310 and/or the energy storage module 320 into AC power and outputs it to the public connection point through the bypass switch 336. At this time, the power generation unit driver 331 operates as a conventional grid-connected inverter, without the need for the AC motor 332 and the synchronous generator 333 to directly invert and output electric energy to the common connection point, thereby reducing energy loss and improving the efficiency of the power generation unit 300 .

If the power generation unit driver 331 works in the AC/DC conversion mode, the alternating current at the public connection point reaches the power generation unit driver 331 via the bypass switch 336, and the power generation unit driver 331 converts the alternating current from the public connection point into direct current and stores it in the energy storage module 320. At this time, the power generation unit driver 331 operates as a charging controller to manage the charging of the energy storage module 320 , thereby improving the utilization rate of the energy storage module 320 and the power generation flexibility of the power generation unit 300 .

As can be seen from the above description, due to the addition of a bypass switch 336 in the power supply equipment 330 of the power generation unit 300, the power generation unit 300 can work in multiple modes, so that it can , power generation environment conditions and the conditions of the power generation unit itself can flexibly control the operation mode of the power generation unit to achieve more efficient and stable operation. At the same time, the power generation unit 300 can also have the function of two-way transmission of electric energy.

Fig. 5 shows a schematic diagram of a power generation system for power supply according to an embodiment of the present invention. As shown in FIG. 5 , the power generation system 500 may include a plurality of power generation units 300 connected in parallel to a common connection point. Wherein, each of the plurality of power generation units 300 has an independent energy input module 310 , an energy storage module 320 and a power supply device 330 .

other deformation

Those skilled in the art should understand that although in the above embodiment, the power generating unit 300 includes the switch 335, the present invention is not limited thereto. In some other embodiments of the present invention, the power generation unit 300 may not include the switch 335 . In this case, one end of the bypass switch 336 is connected between the power generation unit driver 331 and the switch 334, and the other end of the bypass switch 336 is connected between the synchronous generator 333 and the common coupling point.

Those skilled in the art should understand that although in the above embodiment, the multiple power generation units 300 included in the power generation system 500 each have an independent energy storage module 320 , however, the present invention is not limited thereto. In some other embodiments of the present invention, multiple power generation units 300 included in the power generation system 500 may also share the same energy storage module 320 , as shown in FIG. 6A .

Those skilled in the art should understand that although in the above embodiment, the multiple power generation units 300 included in the power generation system 500 each have an independent energy input module 310 and an energy storage module 320 , however, the present invention is not limited thereto. In some other embodiments of the present invention, multiple power generation units 300 included in the power generation system 500 may also share the same energy input module 310 and energy storage module 320 , as shown in FIG. 6B .

Those skilled in the art should understand that various modifications and changes can be made to the above disclosed embodiments without departing from the spirit of the invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (6)

1. a kind of power supply unit, including：

Generator unit driver, for being converted to unidirectional current by converting direct-current power into alternating-current power or by alternating current；

Ac motor, for the alternating current that the generator unit driver is changed to be converted to into mechanical energy；

Synchronous generator, for the mechanical energy being converted into into AC energy and being exported to common connecting point；

The first switch being connected between the generator unit driver and the ac motor；By-pass switch, its one end connects It is connected between the generator unit driver and the first switch, the other end is connected to the synchronous generator and described public Between tie-point；

The second switch being connected between the synchronous generator and the points of common connection；

Wherein, the other end of the by-pass switch is connected between the second switch and the common connecting point, described When by-pass switch disconnects and the first switch and the second switch are closed, the generator unit driver is straight by what is received Stream electricity is converted into alternating current and exports to the ac motor；

When the by-pass switch closure and the first switch and the second switch disconnect, the generator unit driver will be straight Stream electricity is converted to alternating current and is exported to the public interface by the by-pass switch, or will by the by-pass switch Alternating current from the public interface is converted into unidirectional current.

2. power supply unit as claimed in claim 1, wherein,

The by-pass switch is：The catalyst of mechanical contact-type, the chopper of mechanical contact-type, by two power semiconductor switch The two-way switch of device differential concatenation formation or the two-way switch formed by power semiconductor switch and rectifier bridge parallel connection.

3. a kind of generator unit, including：

Energy input module, for capturing the energy and exporting by the unidirectional current of the energy conversion for being captured；

Energy storage module, for storing the electric energy of the energy input module output；And

Power supply unit as described in any one in claim 1 or 2, itself and the energy input module, the energy stores Module and public interface connect, for will turn from the electric energy of the energy input module and/or the energy storage module It is changed to alternating current and exports to the public interface, or unidirectional current will be converted to from the alternating current of the public interface And store to the energy storage module.

4. a kind of electricity generation system, including：

Multiple generator units as claimed in claim 3, wherein, the plurality of generator unit is connected to public with parallel way Contact.

5. electricity generation system as claimed in claim 4, wherein the plurality of generator unit share identical energy input module and Energy storage module.

6. electricity generation system as claimed in claim 4, wherein the plurality of generator unit shares identical energy storage module.