CN103795116A - A power conversion and control device, power supply method and system - Google Patents

Abstract

The invention discloses a power supply conversion and control device, a power supply method and a power supply system, wherein the device comprises: the device comprises a detection module, a control module, a first switch, a second switch, an inverter and an energy processing module; the detection module is used for detecting the power value of the energy end; the control module is connected with the detection module, the control ends of the first switch and the second switch, and is used for generating a first control instruction to control the conduction of the first switch and the second switch when the power value of the energy end detected by the detection module is greater than a first threshold value, wherein a first connection end of the first switch is connected with a first end of the inverter, and a second connection end of the first switch is used for connecting a power grid; and a first connecting end of the second switch is connected with the energy processing module and a second end of the inverter, and a second connecting end of the second switch is used for connecting a storage battery. Therefore, the invention has higher intelligence and reliability.

Description

A power conversion and control device, power supply method and system

technical field

The invention relates to the technical field of power electronics, in particular to a power conversion and control device, a power supply method and a system.

Background technique

At present, there are many new energy power generation systems, such as solar power generation or photovoltaic power generation, wind power generation, hydropower generation and thermal power generation, etc. These power generation systems can be used independently or connected to the grid.

When used independently, these new energy generation systems provide the generated electricity to the load through the conversion and control circuit, and deliver the generated electricity to the battery for storage. When connected to the grid, these new energy generation systems provide the generated electricity to the load and the grid through conversion and control circuits.

The current problem is that these new energy power generation systems cannot store electricity and transmit the generated electricity to the grid when the energy is sufficient, resulting in the power stability and reliability of the power supply system not being further improved.

Contents of the invention

The purpose of the present invention is to propose a power conversion and control device, power supply method and system, which can determine the power supply mode according to the power value of the energy end, and control the inverter to supply power to the load or the grid, so that the power conversion and control device, power supply method And the system has high intelligence and reliability.

For reaching this purpose, the present invention adopts following technical scheme:

In a first aspect, the present invention provides a power conversion and control device, including: a detection module, a control module, a first switch, a second switch, an inverter, and an energy processing module;

The energy processing module is used to convert the energy provided by the energy terminal into direct current;

The detection module is used to detect the power value of the energy terminal;

The inverter is used to convert the direct current output by the energy processing module into alternating current;

The control module is connected to the detection module, the first switch, and the control terminals of the second switch, and is used to generate a second threshold when the power value of the energy terminal detected by the detection module is greater than a first threshold. A control command controls the first switch and the second switch to be turned on;

The first connection end of the first switch is connected to the first end of the inverter, and the second connection end of the first switch is used to connect to the power grid;

The first connection end of the second switch is connected to the energy processing module and the second end of the inverter, and the second connection end of the second switch is used to connect to a storage battery.

In the second aspect, the present invention provides a power supply method suitable for the power conversion and control device provided by the above invention, the method comprising:

Detect the power value of the energy terminal;

Determine the power supply mode according to the power value, convert at least one of the energy in the energy terminal and the storage battery from direct current to alternating current according to the power supply mode, and supply power to the load or the grid; or convert the energy on the grid from alternating current to direct current , to charge the battery.

In a third aspect, the present invention provides a power supply system, which includes: an energy terminal that can provide energy, a storage battery, a load, and a power grid, and the power conversion and control devices provided by all embodiments; wherein, the power conversion and The control device is used to store the energy generated by the energy terminal in the storage battery and deliver it to the power grid while supplying power to the load when the power value of the energy terminal is greater than a first threshold.

The present invention detects the power value of the energy terminal that can provide energy, determines the power supply mode according to the power value, and converts at least one energy in the energy terminal and the storage battery from direct current to alternating current according to the power supply mode, so as to serve the load or the power grid power supply; or, convert the energy on the grid from AC to DC to charge the battery, realize the power supply mode determined according to the power value of the energy terminal, and control the inverter to supply power to the load or the grid, so that the power conversion and control device, power supply The method and system have high intelligence and reliability.

Description of drawings

FIG. 1 is a schematic diagram of a power supply system provided by Embodiment 1 of the present invention;

Fig. 2 is a schematic diagram of a power conversion and control device provided by Embodiment 2 of the present invention;

Fig. 3 is a schematic diagram of a power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 4a is a schematic diagram of the energy trend of the power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 4b is a schematic diagram of the energy trend of the power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 4c is a schematic diagram of the energy trend of the power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 4d is a schematic diagram of the energy trend of the power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 4e is a schematic diagram of the energy trend of the power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 4f is a schematic diagram of the energy trend of the power conversion and control device provided by Embodiment 3 of the present invention;

Fig. 5 is a circuit diagram of a power conversion and control device provided by Embodiment 3 of the present invention;

FIG. 6 is a flow chart of a power supply method provided by Embodiment 4 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only parts related to the present invention are shown in the drawings but not all content.

FIG. 1 is a schematic diagram of a power supply system provided by Embodiment 1 of the present invention. As shown in FIG. 1 , the power supply system includes: a power conversion and control device 11 , a first energy terminal 12 , a second energy terminal 13 , a storage battery 14 , a load 15 and a grid 16 . Wherein, the first energy end 12 provides wind energy, for example, a wind generator can provide wind energy; the second energy end 13 provides solar energy. In the embodiment of the present invention, the power supply system includes the first energy terminal 12 and the second energy terminal 13 , of course, the power supply system may also only include the first energy terminal 12 or the second energy terminal 13 .

The power conversion and control device 11 is used to obtain energy from any one of the first energy terminal 12 , the second energy terminal 13 and the storage battery 14 to supply power to the load 15 or the grid 16 .

The working process of the power conversion and control device 11 is described in detail below from six working scenarios:

(1) When the power grid 16 is normal during the day and the power of wind energy and solar energy is sufficient, the power conversion and control device 11 can control the first energy terminal 12 and the second energy terminal 13 to supply power to the load 15, and then the excess power can be used to meet the needs of the battery. 14 charging power (charging current 5-100A is optional, set according to the capacity of the battery), and then if there is excess power, you can close the grid switch, for example, the STS switch, to generate power on the grid 16, the power supply mode of the system In and off-grid mode. At this time, the sum of solar power and wind power is equal to the sum of load power, charging power and generating power.

(2) When the power grid 16 is normal during the day and the power of wind energy and solar energy is insufficient, the power conversion and control device 11 can control the first energy terminal 12, the second energy terminal 13 and the battery 14 to jointly supply power to the load 15. The power supply mode of the system for off-grid mode. At this time, the sum of solar power, wind power and storage battery is equal to the load power.

(3) When the power grid 16 is normal at night and the wind energy power is sufficient, the power conversion and control device 11 can control the first energy terminal 12 to supply power to the load 15, and then use the excess power to meet the charging power of the battery 14 (charging current 5- 100A is optional, according to the setting of the capacity of the battery), and then if there is excess power, the grid switch can be closed, for example, the STS switch, to generate power on the grid 16, and the power supply mode of the system is parallel and off-grid mode. At this time, the wind energy power is equal to the sum of load power, charging power and generating power.

(4) When the power grid 16 is normal at night and the wind power is insufficient, the power conversion and control device 11 can control the first energy terminal 12 and the storage battery 14 to supply power to the load 15, and the power supply mode of the system is off-grid mode. At this time, the sum of the wind energy power and the storage battery is equal to the load power.

(5) When the power grid 16 is normal, and the solar energy and wind energy are abnormal or faulty, the power conversion and control device 11 can control the battery 14 to supply power to the load 15 until the battery 14 is discharged. At this time, it is in the low-voltage shutdown protection state.

(6) The grid 16 is normal, and after the battery 14 is discharged and shut down at low voltage, the power conversion and control device 11 can control and close the grid switch, use the grid 16 to supply power to the load 15, and use the grid 16 to charge the battery 14 .

FIG. 2 is a schematic diagram of a power conversion and control device provided by Embodiment 2 of the present invention. The power conversion and control device can be applied to the power supply system shown in FIG. 1 . As shown in the figure, the power conversion and control device 11 includes: a detection module 21, a control module 22, an inverter 23, an energy processing module 24 corresponding to an energy terminal that can provide energy, and a first switch 25 and a second switch 26. The energy terminal 20 may be the first energy terminal 12 and the second energy terminal 13 in FIG. 1 .

The detection module 21 is used to detect the power value of the energy terminal 20 that can provide energy. Wherein, the energy provided by the energy terminal 20 may be wind energy or solar energy. In addition, it may also be energy obtained by hydroelectric power generation, energy obtained by thermal power generation (for example, geothermal), and the like.

The control module 22 is used to connect with the control terminals of the detection module 21, the first switch 25 and the second switch 26, and is used for when the power value of the energy terminal 20 detected by the detection module 21 is greater than When the first threshold is reached, a first control instruction is generated to control the first switch 25 and the second switch 26 to be turned on; wherein, the control module 22 is also used to determine the power supply mode according to the power value obtained by the detection module 21, according to The power supply mode controls the inverter 23 to supply power or charge. Wherein, the power supply mode may be an on-grid mode or an off-grid mode.

The inverter 23 is used to convert the direct current output by the energy processing module 24 into alternating current, for example: convert at least one energy in the energy terminal 20 and the storage battery 14 from direct current to alternating current to supply power to the load 15; or, convert The energy on the grid 16 is converted from AC to DC to charge the battery 14 . Wherein, the inverter 23 can convert at least one energy of the energy terminal 20 and the energy of the storage battery 14 from direct current to alternating current to supply power for the load 15 or the grid 16; it can also convert the energy on the grid 16 from alternating current to direct current, Charge the battery 14 .

The energy processing module 24 is used for converting the energy provided by the energy end 20 into direct current.

Wherein, the energy output end of the energy processing module 24 and the energy output end of the storage battery 14 are connected in parallel to the DC input end of the inverter 23, and the AC output end of the inverter 23 is respectively connected to the load 15 and the grid 16 .

The first connection end of the first switch 25 is connected to the first end of the inverter, and the second connection end of the first switch 25 is used to connect to the grid; the first connection end of the second switch 26 The end is connected with the second end of the energy processing module and the inverter, and the second connection end of the second switch 26 is used for connecting the storage battery.

In the embodiment of the present invention, when the detection module 21 detects that the energy power value provided by the energy terminal 20, such as wind energy or solar energy, reaches the first threshold, that is, when the energy provided by the energy terminal is relatively sufficient at this time, the control module 22 determines the power supply mode For the grid-connected and off-grid mode, a first control command is generated to control the first switch 25 and the second switch 26 to be turned on, and to control the grid switch 25 to be turned on, so that the energy generated by the energy terminal is used by the inverter 23 as a load 15 while supplying power, store the remaining energy in the storage battery 14 and send it to the grid 16 .

In the above solution, when the detection module 21 detects that the energy power value provided by the energy terminal 20, such as wind energy or solar energy, is less than the first threshold, that is, the energy provided by the energy terminal is insufficient at this time, the control module 22 determines that the power supply mode is off-grid mode, generating a second control command to control the first switch 25 to be turned off and the second switch 26 to be turned on, so that the energy provided by the energy terminal 20 and the storage battery 14 can be used to supply power to the load 15 through the inverter 23 , without supplying power to the grid 16.

When the detection module 21 detects the energy power value provided by the energy terminal 20, such as wind energy or solar energy, and the wind is very small, that is, after the wind energy and solar energy fail, the control module 22 determines that the power supply mode is an off-grid mode, and generates a second control instruction to control The first switch 25 is turned off, and the second switch 26 is turned on, so that the energy provided by the storage battery 14 is supplied to the load 15 through the inverter 23 until the discharge of the storage battery is terminated.

And, when the discharge of the storage battery 14 is terminated, the control module 22 determines that the power supply mode is the off-grid mode, generates a first control instruction to control the first switch 25 and the second switch 26 to be turned on, so as to supply power to the load 15 through the grid 16, And the battery 14 is charged by using the energy of the grid 16 through the inverter 23 .

Therefore, in the power conversion and control device provided by the embodiment of the present invention, by connecting the energy output terminal of the energy processing module and the energy output terminal of the battery to the DC input terminal of the inverter in parallel, the AC output of the inverter The terminals are respectively connected to the load and the power grid, and use the detection module to detect the power value of the energy terminal that can provide energy. The control module determines the power supply mode according to the power value obtained by the detection module, and controls the power supply mode according to the power supply mode. The inverter converts at least one of the energy of the energy terminal and the storage battery from direct current to alternating current to supply power to the load or the grid, or converts the energy on the grid from alternating current to direct current to charge the storage battery, thereby realizing The power value at the end determines the power supply mode, and controls the inverter to supply power to the load or the grid, so that the power conversion and control device has high intelligence and reliability.

FIG. 3 is a schematic diagram of a power conversion and control device provided by Embodiment 3 of the present invention. The power conversion and control device can be applied to the power supply system shown in FIG. 1 . As shown in the figure, the power conversion and control device includes: a detection module 21, a control module 22, an inverter 23, a first processing circuit 31 corresponding to the first energy terminal 12, and a second processing circuit 31 corresponding to the second energy terminal 13. processing circuit 32 . In addition, the power conversion and control device further includes a first switch 33 and a second switch 34 .

Wherein, the first connection end of the first switch 33 is connected to the first end of the inverter 23, and the second connection end of the first switch 34 is used to connect to the grid;

The first connection terminal of the second switch 34 is respectively connected with the first processing circuit 31 , the second processing circuit 32 and the second terminal of the inverter, and the second connection terminal of the second switch 34 is used for connecting the storage battery. In addition, the first switch 33 and the second switch 34 can both be static transfer switches (Static TransferSwitch, STS) switches, the first switch 3333 is used to receive the control command from the control module 22, and control the connection between the grid 16 and the inverter 23 The connection state between them, the connection state includes a closed state or a disconnected state. The second switch 34 is used to receive a control command from the control module 22 and control the connection state between the battery 14 and the inverter 23 , the connection state includes a closed state or a disconnected state.

The power conversion and control device also includes an output isolation transformer 35, which is connected to the inverter 23 and the load 15 respectively to realize circuit isolation between the inverter 23 and the load 15, and to ensure that the inverter 23 and the load 15 are reliable. Work.

Wherein, the inverter 23 can convert at least one of the energy of the energy terminal and the energy of the storage battery from direct current to alternating current to supply power to the load 15 or the grid 16; Charge.

Compared with FIG. 2 , the energy processing module 24 in FIG. 2 may include the first processing circuit 31 and/or the second processing circuit 32 in FIG. 3 . That is, the energy processing module 24 may only include the first processing circuit 31 corresponding to the first energy terminal 12, or may only include the second processing circuit 32 corresponding to the second energy terminal, or may also include a second processing circuit 32 corresponding to the first energy terminal. A processing circuit 31, and a second processing circuit 32 corresponding to the second energy terminal. Wherein, the energy provided by the first energy terminal is wind energy, and the energy provided by the second energy terminal is solar energy.

The above-mentioned first processing circuit 31 includes a rectification circuit and a first step-down chopper BUCK circuit; the rectification circuit and the first BUCK circuit are respectively used to rectify and step down the wind energy provided by the first energy terminal, and then output energy to the DC input terminal of the inverter; the second processing circuit 32 includes a second BUCK circuit; the second BUCK circuit is used to output energy to the The DC input terminal of the inverter 23.

The energy output end of the first processing circuit 31, the energy output end of the first processing circuit 32, and the energy output end of the storage battery 14 are connected in parallel to the DC input end of the inverter 23, and the AC output end of the inverter 23 They are connected to the load 15 and the grid 16 respectively.

Taking the energy provided by the first energy terminal as wind energy and the energy provided by the second energy terminal as solar energy as an example to specifically illustrate the working process of the control module 22 in the power conversion and control device:

(1) When the sum of the power value of wind energy provided by the first energy terminal 12 and the power value of solar energy provided by the second energy terminal 13 is greater than the second threshold, the power supply mode is determined to be the off-grid mode, and the first control is generated The command controls the first switch 33 and the second switch 34 to be turned on, so that the inverter 23 uses wind energy and solar energy to supply power to the load 15 , the storage battery 14 and the grid 16 successively.

Wherein, when the power value of the wind energy provided by the first energy terminal 12 is relatively large, and the power value of solar energy provided by the second energy terminal 13 is relatively small, but the sum of the two is still greater than the second threshold, the first control can also be generated. The command controls the first switch 33 and the second switch 34 to be turned on, so that the inverter 23 utilizes wind energy to supply power to the load 15 , the storage battery 14 and the grid 16 successively.

The above solution (1) can be applied to the following two application scenarios:

First, as shown in Figure 4a, when the power grid is normal during the day and the power of solar and wind energy is sufficient, the power of solar energy and the power of wind energy are collected together on the DC bus, and the load is supplied with power after passing through the inverter 43 and the isolation transformer 44, satisfying If there is excess power after the load is turned on through the second switch 48, the charging power of the battery can be satisfied (charging current 5-100A is optional, set according to the capacity of the battery), if there is still excess power, through the first switch ( After the STS switch) 41 is turned on, it supplies power to the grid. At this time, the power supply mode of the power conversion and control device is the grid-connected and off-grid mode, and its energy flow is shown by the gray arrow in the figure. Among them, solar power + wind power = load power + charging power + power generation.

Second, as shown in Figure 4b, the power grid is normal at night, and the power of wind energy is sufficient. The power of wind energy is added to the DC bus, and power is supplied to the load after passing through the inverter 43 and the isolation transformer 44. After the load is satisfied, if there is excess power through the first After the second switch 48 is turned on, the charging power of the battery is satisfied (charging current 5-100A is optional, set according to the capacity of the battery), if there is excess power, after the first switch (STS switch) 41 is turned on, the Grid powered. At this time, the power supply mode of the power conversion and control device is the grid-connected and off-grid mode, and its energy flow is shown by the gray arrow in the figure. Among them, wind energy power = load power + charging power + generating power.

(2) When the sum of the power value of wind energy provided by the first energy terminal 12 and the power value of solar energy provided by the second energy terminal 13 is less than the second threshold, it is determined that the power supply mode is the off-grid mode, and a second control is generated The command controls the first switch 33 to be turned off and the second switch 34 to be turned on, so that the inverter 23 uses wind energy, solar energy and the storage battery 14 to supply power to the load 15 .

The above solution (2) can be applied to the following two application scenarios:

First, as shown in Figure 4c, when the power grid is normal during the day, the power of solar and wind energy is insufficient, and the power of solar energy, wind energy, and storage batteries are collected together on the DC bus, the first switch (STS switch) 41 is turned off, and the second switch is closed. The second switch 48 supplies power to the load through the inverter 43 and the isolation transformer 44 . At this time, the power supply mode of the power conversion and control device is the off-grid mode, and the energy flow direction is shown by the gray arrow in the figure. Among them, solar power + wind power + battery = load power.

Second, as shown in Figure 4d, the power grid is normal at night, and the power of wind energy is insufficient. The power of wind energy and the storage battery are collected on the DC bus, the first switch (STS switch) 41 is turned off, the second switch 48 is closed, and the The load is supplied with power after the device 43 and the isolation transformer 44. At this time, the power supply mode of the power conversion and control device is the off-grid mode, and the energy flow direction is shown by the gray arrow in the figure. Among them, wind energy power + storage battery = load power.

(3) When wind energy and solar energy fail, determine that the power supply mode is off-grid mode, generate a second control instruction to control the first switch 33 to be turned off, and the second switch 34 to be turned on, so that the inverter 23 Utilize the energy provided in the storage battery 14 to supply power to the load 15 until the discharge of the storage battery 14 is terminated; The second switch 34 is turned on, so that the load 15 is powered by the grid 16 , and the battery 14 is charged by the grid energy through the inverter 24 .

The above solution (3) can be applied to the following two application scenarios:

First, as shown in Figure 4e, when the power grid is normal, and the solar and wind energy is abnormal or faulty, the storage battery is added to the DC bus, the first switch (STS switch) 41 is turned off, the second switch 48 is closed, and is passed through the isolation transformer 44 Then supply power to the load until the discharge of the battery is terminated (low voltage shutdown protection). At this time, the power supply mode of the power conversion and control device is the off-grid mode, and the energy flow direction is shown by the gray arrow in the figure.

Second, as shown in Figure 4f, the power grid is normal, and after the battery is discharged and turned off at low voltage, the first switch (STS switch) 41 is turned on, the first switch 41 and the second switch 48 are closed, the power grid supplies power to the load, and at the same time through the isolation transformer 44 , The inverter 43 charges the storage battery. At this time, the power supply mode of the power conversion and control device is the grid-connected and off-grid mode, and its energy flow is shown by the gray arrow in the figure.

Taking the circuit diagram shown in FIG. 5 as an example, the specific implementation form of each part of the power conversion and control device provided by the above embodiment will be described in detail. As shown in the figure, the wind generator can be the first energy terminal 12 , and the photovoltaic plate can be the second energy terminal 13 .

Capacitor C5, capacitor C6, transistor K2, diode D2, and inductor L2 form the first BUCK circuit; diode D3, diode D4, diode D5, and diode D6 form the rectifier circuit; the first BUCK circuit and the rectifier circuit form the first energy terminal 12 The corresponding first processing circuit 31.

Capacitor C1 , capacitor C2 , transistor K1 , diode D1 , and inductor L1 form a second BUCK circuit, and the second BUCK circuit forms a second processing circuit 32 corresponding to the second energy terminal 13 .

The triode K3 , the triode K4 , the triode K5 and the triode K6 form an inverter 23 .

The STS switch is the first switch 33 .

The TRANS transformer is an output isolation transformer 35 .

The BAT+ terminal and the BAT- terminal are used to connect to the storage battery; or first pass through the second switch 34 before connecting to the storage battery.

In the embodiment of the present invention, the energy output by the wind generator is firstly rectified by the rectifier circuit, and after being stepped down by the first BUCK circuit, the solar energy provided by the photovoltaic plate is connected to the output terminal of the battery after being stepped down by the second BUCK circuit. They are connected in parallel to the DC bus, and then the energy is supplied to the load or the grid through the inverter and the isolation transformer.

FIG. 6 is a schematic diagram of a power supply method provided by Embodiment 4 of the present invention. The power supply method can be applied to the power supply system shown in FIG. 1 , and its executive body is the power conversion and control device described in all the above-mentioned embodiments. As shown in the figure, the power supply method includes:

Step 610, the power conversion and control device detects the power value of the energy terminal;

Step 620, the power conversion and control device determines the power supply mode according to the detected power value, and converts at least one kind of energy in the energy terminal and the storage battery from direct current to alternating current according to the power supply mode to supply power to the load or the grid; or, The energy on the grid is converted from AC to DC to charge the battery.

In one embodiment, step 620 may specifically include:

When it is detected that the energy power value provided by the energy terminal reaches the first threshold, determine that the power supply mode is the off-grid mode, and use the energy provided by the energy terminal to supply power to the load, the storage battery and the grid successively; or,

When it is detected that the energy power value provided by the energy terminal is less than the first threshold, it is determined that the power supply mode is an off-grid mode, and the energy provided by the energy terminal and the storage battery is used to supply power to the load; or; or,

When a fault occurs at the energy end, determine that the power supply mode is the off-grid mode, and use the energy provided by the battery to supply power to the load until the battery discharge is terminated; and, when the battery discharge is terminated, determine that the power supply mode is the off-grid mode, Control the grid to supply power to the load, and use the grid energy to charge the battery.

In another embodiment, the energy terminal includes a first energy terminal that provides wind energy and a second energy terminal that provides solar energy, and step 620 may specifically include:

When the sum of the power value of the wind energy provided by the first energy terminal and the power value of the solar energy provided by the second energy terminal is greater than the second threshold, the power supply mode is determined to be the parallel and off-grid mode, and the wind energy provided by the first energy terminal is utilized and the solar energy provided by the second energy terminal successively supply power to the load, the storage battery and the grid; or,

When the sum of the power value of wind energy provided by the first energy terminal and the power value of solar energy provided by the second energy terminal is less than the second threshold, it is determined that the power supply mode is an off-grid mode, and the power provided by the first energy terminal is used The wind energy, the solar energy provided by the second energy terminal, and the energy provided by the storage battery supply power to the load; or,

When wind energy and solar energy fail, determine that the power supply mode is a low-voltage shutdown protection mode, and use the energy provided by the battery to supply power to the load until the battery discharge is terminated; and, when the battery discharge is terminated, determine that the power supply mode is off-grid Mode, control the grid to supply power to the load, and use the grid energy to charge the battery.

Therefore, the embodiment of the present invention detects the power value of the energy terminal that can provide energy, determines the power supply mode according to the power value, and converts at least one of the energy of the energy terminal and the storage battery from direct current to alternating current according to the power supply mode, Supply power to the load or grid; or convert the energy on the grid from AC to DC to charge the battery, realize the power supply mode determined according to the power value of the energy terminal, and control the inverter to supply power to the load or grid, so that the power supply method has High intelligence and reliability.

The present invention also provides a power supply system, which includes: an energy terminal, a storage battery, a load, a power grid, and the power conversion and control devices described in all the above-mentioned embodiments. Wherein, the energy end may include a first energy end providing wind energy and a second energy end providing solar energy. The power conversion and control device is used to supply power to the load when the power value of the energy terminal is greater than a first threshold, store the energy generated by the energy terminal in the storage battery, and transmit it to the power grid.

Claims (9)

1. A power conversion and control device, comprising: the device comprises a detection module, a control module, a first switch, a second switch, an inverter and an energy processing module;

the energy processing module is used for converting energy provided by the energy end into direct current;

the detection module is used for detecting the power value of the energy end;

the inverter is used for converting the direct current output by the energy processing module into alternating current;

the control module is connected with the detection module, the first switch and the control end of the second switch, and is used for generating a first control instruction to control the conduction of the first switch and the second switch when the power value of the energy end detected by the detection module is greater than a first threshold value;

the first connection end of the first switch is connected with the first end of the inverter, and the second connection end of the first switch is used for connecting a power grid;

and a first connecting end of the second switch is connected with the energy processing module and a second end of the inverter, and a second connecting end of the second switch is used for connecting a storage battery.

2. The power conversion and control device of claim 1, wherein the control module is specifically configured to:

when the power value of the energy end detected by the detection module is larger than a first threshold value, the control module determines that a power supply mode is a grid-connected and off-grid mode, and generates a first control instruction to control the first switch and the second switch to be conducted, so that the inverter supplies power to a load by using the energy generated by the energy end, and simultaneously stores the residual energy into the storage battery and transmits the residual energy to the power grid;

when the detection module detects that the energy power value provided by the energy end is smaller than a first threshold value, the control module determines that the power supply mode is an off-grid mode, and generates a second control instruction to control the first switch to be switched off and the second switch to be switched on, so that the inverter supplies power to the load by using the energy provided by the energy end and the storage battery;

when the detection module detects that the energy end has a fault, the control module determines that a power supply mode is an off-grid mode, generates a second control instruction to control the first switch to be switched off and the second switch to be switched on, so that the inverter supplies power to a load by using energy provided by the storage battery until the storage battery is discharged; and after the storage battery is discharged, the control module determines that the power supply mode is a grid-connected and off-grid mode, generates a first control instruction to control the first switch and the second switch to be switched on, so that the power is supplied to the load through the power grid, and the storage battery is charged through the inverter by using the energy of the power grid.

3. The power conversion and control device according to claim 1 or 2, wherein the energy processing module comprises a first processing circuit corresponding to a first energy terminal and/or a second processing circuit corresponding to a second energy terminal;

the first processing circuit comprises a rectifying circuit and a first BUCK chopper BUCK circuit; the rectifying circuit and the first BUCK circuit are respectively used for rectifying and reducing the wind energy provided by the first energy end and then outputting the energy to the direct current input end of the inverter;

the second processing circuit comprises a second BUCK circuit; the second BUCK circuit is used for outputting energy to the direct-current input end of the inverter after the solar energy provided by the second energy end is subjected to voltage reduction;

the energy output end of the first processing circuit, the energy output end of the first processing circuit and the energy output end of the storage battery are connected to the direct current input end of the inverter in parallel, and the alternating current output end of the inverter is connected with the load and the power grid respectively.

4. The power conversion and control device of claim 3, wherein the inverter is specifically configured to: converting the energy of at least one of the energy end and the energy of the storage battery from direct current to alternating current to supply power to a load or a power grid; or when the inverter is a charger, the energy on the power grid is converted from alternating current to direct current to charge the storage battery.

5. The power conversion and control device according to claim 4, wherein the control module is further configured to:

when the sum of the power value of the wind energy provided by the first energy end and the power value of the solar energy provided by the second energy end is larger than a second threshold value, determining that the power supply mode is a grid-connected mode and an off-grid mode, controlling the conduction of the power grid switch, and generating a first control instruction to control the conduction of the first switch and the second switch, so that the inverter supplies power to the load, the storage battery and the power grid by utilizing the wind energy and the solar energy in sequence; or,

when the sum of the power value of the wind energy provided by the first energy end and the power value of the solar energy provided by the second energy end is smaller than a second threshold value, determining that the power supply mode is an off-grid mode, and generating a second control instruction to control the first switch to be switched off and the second switch to be switched on, so that the inverter supplies power to the load by using the wind energy, the solar energy and the storage battery; or,

when wind energy and solar energy are in fault, the control module determines that a power supply mode is an off-grid mode, and generates a second control instruction to control the first switch to be switched off and the second switch to be switched on, so that the inverter supplies power to the load by using energy provided by the storage battery until the storage battery is discharged; and after the storage battery is discharged, determining that the power supply mode is a grid-connected and off-grid mode, generating a first control instruction to control the first switch and the second switch to be conducted, so that the power grid is used for supplying power to the load, and the storage battery is charged by the inverter through the energy of the power grid.

6. A power supply method applied to the power conversion and control device according to any one of claims 1 to 5, wherein the method comprises:

detecting a power value of an energy end;

determining a power supply mode according to the power value, and converting at least one energy of the energy end and the storage battery from direct current to alternating current according to the power supply mode to supply power to a load or a power grid; or, the energy on the power grid is converted from alternating current to direct current to charge the storage battery.

7. The power supply method according to claim 6, wherein the power supply mode is determined based on the power value, and at least one of the energy terminal and the storage battery is converted from direct current to alternating current according to the power supply mode to supply power to a load or a power grid; or, converting the energy on the power grid from alternating current to direct current, and specifically including:

when detecting that the energy power value provided by the energy end reaches a first threshold value, determining that a power supply mode is a grid-connected and off-grid mode, and supplying power to a load, a storage battery and a power grid in sequence by using the energy provided by the energy end; or,

when detecting that the energy power value provided by the energy end is smaller than a first threshold value, determining that a power supply mode is an off-grid mode, and supplying power to a load by using the energy provided by the energy end and a storage battery; or,

when the energy end is detected to have a fault, determining that a power supply mode is an off-grid mode, and supplying power to a load by using the energy provided by the storage battery until the storage battery is discharged; and after the storage battery is discharged, determining that the power supply mode is a grid-connected and off-grid mode, controlling the power grid to supply power to the load, and charging the storage battery by using the energy of the power grid.

8. The power supply method according to claim 6, wherein the energy terminals include a first energy terminal providing wind energy and a second energy terminal providing solar energy; determining a power supply mode according to the power value, and converting at least one energy of the energy end and the storage battery from direct current to alternating current according to the power supply mode to supply power to a load or a power grid; or, converting the energy on the power grid from alternating current to direct current, and specifically including:

when the sum of the power value of the wind energy provided by the first energy end and the power value of the solar energy provided by the second energy end is larger than a second threshold value, determining that the power supply mode is a grid-connected mode and supplying power to a load, a storage battery and a power grid by using the wind energy provided by the first energy end and the solar energy provided by the second energy end in sequence; or,

when the sum of the power value of the wind energy provided by the first energy end and the power value of the solar energy provided by the second energy end is smaller than a second threshold value, determining that the power supply mode is an off-grid mode, and supplying power to a load by using the wind energy provided by the first energy end, the solar energy provided by the second energy end and the energy provided by a storage battery; or,

when the wind energy and the solar energy are in failure, determining that the power supply mode is an off-grid mode, and supplying power to a load by using the energy provided by the storage battery until the storage battery is discharged; and after the storage battery is discharged, determining that the power supply mode is a grid-connected and off-grid mode, so that the power grid is used for supplying power to the load, and the storage battery is charged by the energy of the power grid through the inverter.

9. A power supply system, characterized in that the system comprises: energy terminals, accumulators, loads, grids, and the power conversion and control device of any of claims 1-5; the power supply conversion and control device is used for supplying power to the load and storing energy generated by the energy end to the storage battery and transmitting the energy to the power grid when the power value of the energy end is larger than a first threshold value.

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