Direct-current power supply system and electric equipment

Abstract

The invention discloses a direct current power supply system and electric equipment, the direct current power supply system comprises a direct current bus, at least one energy supply and storage module connected with the direct current bus, and a flexible regulation and control device; the flexible regulation and control device is connected to the direct-current bus and is used for detecting electrical parameters of the direct-current bus and setting a normal operation area for the direct-current bus; and the flexible regulation and control device is also connected to all the energy supply and storage modules, and is used for regulating the operation state of the energy supply and storage modules according to whether the electrical parameters are in the normal operation area. Compared with the prior art, power adjustment is carried out on each energy supply and storage module based on the electrical parameters, dependence on a communication link is not needed, and the response speed is high.

Description

Technical Field

[0001] The invention relates to a distributed power supply system, in particular to a direct current power supply system and electrical equipment. Background Art

[0002] With the development of distributed renewable energy, especially the promotion and application of photovoltaic storage and direct-flexible technology, the energy consumption status and mode on the user side have undergone tremendous changes, from the traditional top-down power grid to the distributed and off-grid self-sufficient photovoltaic storage system, which has put forward new requirements for the balanced management and control of power supply and load.

[0003] In the prior art, the AC / DC hybrid power supply system adopts load classification and DC bus voltage classification for power supply, and uses distributed bidirectional converters and distribution switches for switching to balance energy consumption. For example, in the patent CN118157245A, a multi-load graded AC / DC hybrid active distribution system and a flexible control method for buildings are proposed. The DC system and the AC system interact with each other through bidirectional converters and unidirectional converters, and segmented DC bus distribution is used. By changing the switch state, load switching of different circuits is realized to achieve power balance. This solution only focuses on the power balance management of AC / DC hybrid power supply, and does not solve the control of flexible power consumption of the same or different DC buses and loads.

[0004] In addition, in the prior art, when adjusting each power converter, it is necessary to rely on a communication link for adjustment, which has a slow response speed and affects the operation of the entire system.

[0005] Therefore, how to design a DC power supply system and electrical equipment to improve the regulation response speed is a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0006] In view of the problem of slow response speed when adjusting each power converter in the prior art, the present invention proposes a direct current power supply system and power-consuming equipment.

[0007] The technical solution of the present invention is to propose a direct current power supply system, 1. comprising a direct current bus (10), at least one energy supply and storage module connected to the direct current bus (10), characterized in that it also comprises a flexible control device (4);

[0008] The flexible control device (4) is connected to the DC bus (10) to detect electrical parameters of the DC bus (10) and set (10) a normal operating area for the DC bus;

[0009] The flexible control device (4) is also connected to all the energy supply and storage modules, and is used to adjust the operating state of the energy supply and storage modules according to whether the electrical parameters are in the normal operating area.

[0010] Furthermore, the energy supply and storage module comprises a photovoltaic module (1), and a first DC / DC module (2) connecting the photovoltaic module (1) and the DC bus (10);

[0011] The first DC / DC module (2) is configured as a boost topology and has at least one power switch tube, and the flexible control device (4) adjusts the output power of the first DC / DC module (2) through the power switch tube.

[0012] Furthermore, the first DC / DC module (2) comprises: a switch tube Q5, an inductor L3, a diode D1, and a capacitor C3;

[0013] One end of the inductor L3 is connected to the first output end of the photovoltaic module (1), the other end of the inductor L3 is connected to the positive electrode of the diode D1, and the negative electrode of the diode D1 is connected to the flexible control device (4);

[0014] The second output end of the photovoltaic module (1) is connected to the DC bus (10); one end of the switch tube Q5 as a power switch tube is connected between the inductor L3 and the diode D1; and the other end of the switch tube Q5 is connected between the second output end of the photovoltaic module (1) and the DC bus (10);

[0015] One end of the capacitor C3 is connected between the diode D1 and the flexible control device (4), and the other end of the capacitor C3 is connected between the second output end of the photovoltaic module (1) and the DC bus (10);

[0016] Furthermore, the energy supply and storage module comprises an energy storage battery (11), and a second DC / DC module (9) connecting the energy storage battery (11) and the DC bus (10);

[0017] The second DC / DC module (9) is a bidirectional buck-boost topology, and is used to allow electric energy to flow bidirectionally between the energy storage battery (11) and the DC bus (10).

[0018] Furthermore, the second DC / DC module includes: a switch tube Q10, a switch tube Q11, an inductor L5, a capacitor C7, and a capacitor C8;

[0019] The second output end of the energy storage battery (11) is connected to the DC bus (10), the first end of the switch tube Q10 is connected to the flexible control device (4), the second end of the switch tube Q10 is connected to the first end of the switch tube Q11, and the second end of the switch tube Q11 is connected between the second output end of the energy storage battery (11) and the DC bus (10);

[0020] One end of the inductor L5 is connected between the second end of the switch tube Q10 and the first end of the switch tube Q11, and the other end of the inductor L5 is connected to the first output end of the energy storage battery (11);

[0021] One end of the capacitor C7 is connected between the switch tube Q10 and the flexible control device (4), and the other end of the capacitor C7 is connected between the second output end of the energy storage battery (11) and the DC bus (10);

[0022] One end of the capacitor C8 is connected between the inductor L5 and the first output end of the energy storage battery (11), and the other end of the capacitor C8 is connected between the second output end of the energy storage battery (11) and the DC bus (10).

[0023] Furthermore, the energy supply and storage module comprises at least one DC load and a third DC / DC module (14) connecting the DC load and the DC bus (10);

[0024] The third DC / DC module (14) is an isolation converter topology, used for converting high-voltage direct current on the direct current bus (10) into low-voltage direct current, and supplying power to the direct current load.

[0025] Furthermore, the third DC / DC module (14) comprises: a transformer T1, a switch tube Q6, a switch tube Q7, a switch tube Q8, a switch tube Q9, an inductor L4, a capacitor C4, a capacitor C5, and a capacitor C6;

[0026] wherein one end of the capacitor C5 is connected to the second end of the primary side of the transformer T1, the other end of the capacitor C5 is connected to the DC bus (10), the first end of the switch tube Q6 is connected to the flexible control device (4), the second end of the switch tube Q6 is connected to the first end of the switch tube Q7, the second end of the switch tube Q7 is connected between the capacitor C5 and the DC bus (10), one end of the capacitor C4 is connected between the switch tube Q6 and the flexible control device (4), and the other end of the capacitor C4 is connected between the capacitor C5 and the DC bus (10);

[0027] The secondary side of the transformer T1 adopts a winding with a center tap end, the first output end of the DC load is connected to the center tap end of the secondary side of the transformer T1, the first end of the switch tube Q9 is connected to the second end of the secondary side of the transformer T1, the second end of the switch tube Q9 is connected to the second output end of the DC load, the first end of the switch tube Q8 is connected to the first end of the secondary side of the transformer T1, and the second end of the switch tube Q8 is connected between the switch tube Q9 and the second output end of the DC load;

[0028] One end of the capacitor C6 is connected between the first output end of the DC load and the center tap end of the secondary side of the transformer T1 , and the other end of the capacitor C6 is connected between the switch tube Q9 and the second output end of the DC load.

[0029] Furthermore, the energy supply and storage module comprises an AC power grid (6), and an AC / DC module (8) connecting the AC power grid (6) and the DC bus (10);

[0030] The AC / DC module (8) is a bridge topology, and is used to realize bidirectional conversion between the alternating current of the alternating current grid (6) and the direct current of the direct current bus (10), and the AC / DC module (8) has at least one set of bridge arms, and the flexible control device (4) realizes output power regulation of the alternating current grid (6) by adjusting the on-off state of the switch tube on the bridge arm.

[0031] Furthermore, the energy supply and storage module includes: a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, a switching switch S1, and a switching switch S2;

[0032] The first end of the switch tube Q1 and the first end of the switch tube Q3 are connected to the flexible control device (4), the second end of the switch tube Q2 and the second end of the switch tube Q4 are connected to the DC bus (10), the second end of the switch tube Q1 is connected to the first end of the switch tube Q2, and the second end of the switch tube Q3 is connected to the first end of the switch tube Q4;

[0033] One end of the switch S1 is connected to the first output end of the AC power grid (6), and the other end of the switch S1 is connected in series with the inductor L1 and then connected between the switch tube Q1 and the switch tube Q2;

[0034] One end of the switch S2 is connected to the second output end of the AC power grid (6), and the other end of the switch S2 is connected in series with the inductor L2 and then connected between the switch tube Q3 and the switch tube Q4;

[0035] One end of the capacitor C1 is connected between the switch S1 and the inductor L1, the other end of the capacitor C1 is connected between the switch S2 and the inductor L2, one end of the capacitor C2 is connected between the flexible control device (4) and the connection point between the switch tube Q1 and the switch tube Q3, and the other end of the capacitor C2 is connected between the DC bus (10) and the connection point between the switch tube Q2 and the switch tube Q4.

[0036] Furthermore, the DC power supply system has three working modes, and the three working modes are set according to whether the electrical parameters are in the normal operating area;

[0037] When the electrical parameter is in the normal operating range, the DC power supply system operates in a first operating mode;

[0038] When the electrical parameter exceeds the lower limit of the normal operating range, the DC power supply system operates in the second operating mode;

[0039] When the electrical parameter exceeds the upper limit value of the normal operating range, the DC power supply system operates in the third operating mode.

[0040] Furthermore, when the DC power supply system operates in the first working mode, the flexible control device (4) controls the photovoltaic module (1), the AC power grid (6), the energy storage battery (11), and the DC load to maintain the existing power operation.

[0041] Furthermore, when the DC power supply system operates in the second working mode, the flexible control device (4) determines the maximum output power of the photovoltaic module (1) and the energy storage battery (11) according to the peak and valley state of the AC power grid (6), and controls the flexible load connected to the flexible control device (4) to reduce the operating power.

[0042] Furthermore, when the DC power supply system operates in the third working mode, the flexible control device (4) adjusts the output power of the photovoltaic module (1) and the energy storage battery (11) according to the peak and valley state of the AC power grid (6), and controls the flexible load connected to the flexible control device (4) to restore the rated operating power.

[0043] The present invention also provides an electrical device, wherein the electrical device has the above-mentioned DC power supply system.

[0044] Furthermore, the electrical equipment is an air conditioner.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] 1. In the present invention, the electrical parameters of the DC bus are collected by a flexible control device, and the operating state of each energy storage module is adjusted according to the electrical parameters, without relying on a communication link, and the response speed is fast;

[0047] 2. The present invention can set the normal operating area of ​​the DC bus through a flexible control device, and according to whether the DC bus is in the normal operating area, control the power reduction or increase of each energy storage module to quickly achieve power balance. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0049] Figure 1 is a system block diagram of a DC power supply system of the present invention;

[0050] Figure 2 A circuit topology diagram of the DC power supply system in the present invention;

[0051] Figure 3 A flow chart of power regulation based on electrical parameters of a DC bus in the present invention;

[0052] Figure 4 It is a schematic diagram of voltage partitioning during flexible regulation in the present invention. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0054] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0055] The principle and structure of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

[0056] In the prior art, when adjusting each power converter, it is necessary to rely on a communication link for adjustment, which has a slow response speed and affects the operation of the entire system.

[0057] In view of the above problems, the present invention proposes a DC power supply system, see Figure 1 , which includes a DC bus 10, at least one energy supply and storage module connected to the DC bus 10, and a flexible control module 4;

[0058] The flexible control device 4 is also connected to the DC bus 10 and all energy supply and storage modules respectively, and its specific working principle is as follows:

[0059] The electrical parameters of the DC bus 10 are detected through the part connected to the DC bus 10. The electrical parameters here may be parameters such as voltage, current, and output power. At the same time, a normal operating area is set for the DC bus 10, and then the operating states of all energy supply and storage modules are adjusted according to whether the detected electrical parameters are in the normal operating area, so as to quickly achieve power balance.

[0060] In a preferred embodiment of the present invention, the electrical parameter is voltage, and the normal operating range is also set according to the voltage. The range of the normal operating range is set as [Udown, Uup] in the present invention, where Udown is the lower limit of the normal operating range, and Uup is the upper limit of the normal operating range;

[0061] The above-mentioned normal operating area can be determined by the operating conditions of the entire DC power supply system, the transformer, and the full power voltage operating range of the load. However, since the load operating state of each device in the DC power supply system is uncertain, the range of the normal operating area can be flexibly set and changed by the flexible control device 4. For example, the normal operating range of the bus voltage of the DC bus 10 is [380V, 420V]. Within this range, each converter does not perform flexible adjustment, and the power balance control of the DC bus 10 is carried out according to the conventional stable DC bus 10.

[0062] When the normal operation area of ​​the DC power supply system needs to be expanded, it can be changed to [350V, 450V], as long as it does not exceed the protection value of the DC power supply system.

[0063] See also Figure 1 In the present invention, the energy storage module includes a photovoltaic module 1, a first DC / DC module 2 (also referred to as an attached Figure 1 DC / DC module in 1);

[0064] The first DC / DC module 2 is configured as a boost topology and has at least one power switch tube. The flexible control device 4 adjusts the output power of the first DC / DC module 2 through the power switch tube.

[0065] See also Figure 2 The first DC / DC module 2 includes: a switch tube Q5, an inductor L3, a diode D1, and a capacitor C3;

[0066] One end of the inductor L3 is connected to the first output end of the photovoltaic module 1, the other end of the inductor L3 is connected to the positive electrode of the diode D1, and the negative electrode of the diode D1 is connected to the flexible control device 4;

[0067] The second output end of the photovoltaic module 1 is connected to the DC bus 10, one end of the switch tube Q5 as a power switch tube is connected between the inductor L3 and the diode D1, and the other end of the switch tube Q5 is connected between the second output end of the photovoltaic module 1 and the DC bus 10;

[0068] One end of the capacitor C3 is connected between the diode D1 and the flexible control device 4, and the other end of the capacitor C3 is connected between the second output end of the photovoltaic module 1 and the DC bus 10;

[0069] Here, the photovoltaic module 1 and the first DC / DC module 2 constitute photovoltaic power generation to achieve regulation and control of the power generation power of the photovoltaic module. The first DC / DC module 2 is used for step-up conversion. In normal operation, it works at the MPPT (maximum power point tracking mode) maximum photovoltaic power point;

[0070] When the voltage of the DC bus 10 is greater than the upper limit of the above-mentioned normal operating area, and the AC power grid is off-grid or grid-connected power generation is not allowed, the photovoltaic module 1 enters a power-limited operation mode, and reduces the photovoltaic power generation power by adjusting the duty cycle of the switch tube Q5 (i.e., the power switch tube).

[0071] See also Figure 1 In the present invention, the energy storage module includes: an energy storage battery 11, a second DC / DC module 9 (i.e. Figure 1 DC / DC module 2);

[0072] The second DC / DC module 9 is a bidirectional buck-boost topology, and is used to allow electric energy to flow bidirectionally between the energy storage battery 11 and the DC bus 10 .

[0073] See also Figure 2 The second DC / DC module 9 includes: a switch tube Q10, a switch tube Q11, an inductor L5, a capacitor C7, and a capacitor C8;

[0074] The second output end of the energy storage battery 11 is connected to the DC bus 10, the first end of the switch tube Q10 is connected to the flexible control device 4, the second end of the switch tube Q10 is connected to the first end of the switch tube Q11, and the second end of the switch tube Q11 is connected between the second output end of the energy storage battery 11 and the DC bus 10;

[0075] One end of the inductor L5 is connected between the second end of the switch tube Q10 and the first end of the switch tube Q11, and the other end of the inductor L5 is connected to the first output end of the energy storage battery 11;

[0076] One end of the capacitor C7 is connected between the switch tube Q10 and the flexible control device 4, and the other end of the capacitor C7 is connected between the second output end of the energy storage battery 11 and the DC bus 10;

[0077] One end of the capacitor C8 is connected between the inductor L5 and the first output end of the energy storage battery 11 , and the other end of the capacitor C8 is connected between the second output end of the energy storage battery 11 and the DC bus 10 .

[0078] Here, the second DC / DC module 9 and the energy storage battery 11 constitute an energy storage system, which participates in regulating the power balance of the DC power supply system mainly by controlling the charging and discharging power of the second DC / DC module when the DC power supply system operates normally.

[0079] See also Figure 1 The energy storage module includes at least one DC load, a third DC / DC module 14 (also referred to as an attached DC bus 10) connecting the DC load to the DC bus 10. Figure 1 DC / DC module in 3);

[0080] The third DC / DC module 14 is an isolation converter topology, which is used to convert the high-voltage DC power on the DC bus 10 into low-voltage DC power and supply power to the DC load.

[0081] See also Figure 2 The third DC / DC module 14 includes: a transformer T1, a switch tube Q6, a switch tube Q7, a switch tube Q8, a switch tube Q9, an inductor L4, a capacitor C4, a capacitor C5, and a capacitor C6;

[0082] Among them, one end of the capacitor C5 is connected to the second end of the primary side of the transformer T1, the other end of the capacitor C5 is connected to the DC bus 10, the first end of the switch tube Q6 is connected to the flexible control device 4, the second end of the switch tube Q6 is connected to the first end of the switch tube Q7, the second end of the switch tube Q7 is connected between the capacitor C5 and the DC bus 10, one end of the capacitor C4 is connected between the switch tube Q6 and the flexible control device 4, and the other end of the capacitor C4 is connected between the capacitor C5 and the DC bus 10;

[0083] The secondary side of the transformer T1 adopts a winding with a center tap end, the first output end of the DC load is connected to the center tap end of the secondary side of the transformer T1, the first end of the switch tube Q9 is connected to the second end of the secondary side of the transformer T1, the second end of the switch tube Q9 is connected to the second output end of the DC load, the first end of the switch tube Q8 is connected to the first end of the secondary side of the transformer T1, and the second end of the switch tube Q8 is connected between the switch tube Q9 and the second output end of the DC load;

[0084] One end of the capacitor C6 is connected between the first output end of the DC load and the center tap end of the secondary side of the transformer T1 , and the other end of the capacitor C6 is connected between the switch tube Q9 and the second output end of the DC load.

[0085] like Figure 1As shown, in the present invention, there are three DC loads, namely, the first DC load 12 (also known as the attached Figure 1 The DC load 1 in the figure), the second DC load 15 (also the attached Figure 1 The DC load 2 in the figure), the third DC load 16 (also the attached Figure 1 The DC load 3), the above three DC loads can all participate in the work and take power from the third DC / DC module 14 to maintain the work;

[0086] Here, the third DC / DC module 14 mainly provides a low-voltage isolated DC bus voltage to power the first DC load 12, the second DC load 15, and the third DC load 16. The power supply voltage is Ubus2, which is 48VDC.

[0087] The circuit of the third DC / DC module 14 is mainly composed of an isolation converter topology, which mainly realizes the conversion of high-voltage DC voltage into low-voltage DC voltage to supply power to the DC load. When the voltage of the DC bus 10 is within the normal operating range, the output power of the third DC / DC module 14 is equal to the operating power of the DC load, and the DC bus 10 is kept constant.

[0088] When the voltage of the DC bus 10 is lower than the lower limit of the above normal operating range, the third DC / DC module 14 will operate in the power limiting mode, reducing the output voltage in the same proportion, and some DC loads adjust their own operating power or shut down by detecting the input voltage.

[0089] See also Figure 1 , the energy storage module includes an AC grid 6, an AC / DC module 8 connecting the AC grid 6 and a DC bus 10;

[0090] The AC / DC module 8 is a bridge topology, which is used to realize bidirectional conversion between the AC power of the AC power grid 6 and the DC power of the DC bus 10, and the AC / DC module 8 has at least one set of bridge arms. The flexible control device 4 adjusts the output power of the AC power grid 6 by adjusting the on-off state of the switch tube on the bridge arm.

[0091] See also Figure 2 The energy storage module includes: a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, a switching switch S1, and a switching switch S2;

[0092] The first end of the switch tube Q1 and the first end of the switch tube Q3 are connected to the flexible control device 4, the second end of the switch tube Q2 and the second end of the switch tube Q4 are connected to the DC bus 10, the second end of the switch tube Q1 is connected to the first end of the switch tube Q2, and the second end of the switch tube Q3 is connected to the first end of the switch tube Q4;

[0093] One end of the switch S1 is connected to the first output end of the AC power grid 6, and the other end of the switch S1 is connected in series with the inductor L1 and then connected between the switch tube Q1 and the switch tube Q2;

[0094] One end of the switch S2 is connected to the second output end of the AC power grid 6, and the other end of the switch S2 is connected in series with the inductor L2 and then connected between the switch tube Q3 and the switch tube Q4;

[0095] One end of capacitor C1 is connected between switch S1 and inductor L1, the other end of capacitor 1 is connected between switch S2 and inductor L2, one end of capacitor C2 is connected between the flexible control device 4 and the connection point between switch tube Q1 and switch tube Q3, and the other end of capacitor C2 is connected between the DC bus 10 and the connection point between switch tube Q2 and switch tube Q4.

[0096] Here, the AC power grid 6 is used to provide electrical energy outside the DC power supply system, and the AC / DC module 8 is used to convert AC power into DC power, or to realize DC inverter grid connection, realize bidirectional power transmission, and constitute a bidirectional inverter converter. The circuit of the AC / DC module is mainly a bridge topology. The flexible control device 4 can adjust the power on the grid side by adjusting the states of the switch tubes Q1, Q2, Q3, and Q4. Through flexible control and management of DC side energy consumption, constant power operation on the grid side can be achieved, reducing the impact on the grid.

[0097] See also Figure 1 In the present invention, the flexible control device 4 is also connected to an information terminal 5, which can be a mobile phone APP, a web page, a computer, etc., and can display the operating status, fault information, energy consumption, etc. of the DC power supply system.

[0098] In the present invention, the DC bus 10 is also connected to at least one flexible load. Figure 1 In the embodiment, two flexible loads are provided, namely, a first flexible load 17 (i.e. Figure 1 The flexible load 1) and the second flexible load 18 (i.e. Figure 1 Medium flexible load 2), flexible load refers to the load that can adjust the power by detecting the input DC voltage value, such as air conditioners, water heaters and other electrical appliances;

[0099] Its working principle is: when it is detected that the voltage of the DC bus 10 is less than the lower limit of the normal operating area, the operating power is reduced;

[0100] When it is detected that the voltage of the DC bus 10 is greater than the upper limit of the normal operating area, the power is restored or increased to the rated power.

[0101] Furthermore, the DC power supply system in the present invention has three working modes, and the three working modes are set according to whether the electrical parameters are in the normal operating area;

[0102] When the electrical parameters are in the normal operating range, the DC power supply system operates in the first working mode;

[0103] When the electrical parameters exceed the lower limit of the normal operating area, the DC power supply system operates in the second working mode;

[0104] When the electrical parameters exceed the upper limit of the normal operating range, the DC power supply system operates in the third operating mode.

[0105] When the DC power supply system operates in the first working mode, the flexible control device 4 controls the photovoltaic module 1, the AC power grid 6, the energy storage battery 11, and the DC load to maintain the existing power operation.

[0106] When the DC power supply system operates in the second working mode, the flexible control device 4 determines the maximum output power of the photovoltaic module 1 and the energy storage battery 11 according to the peak and valley state of the AC power grid 6, and controls the flexible load connected to the flexible control device 4 to reduce the operating power.

[0107] When the DC power supply system operates in the third working mode, the flexible control device 4 adjusts the output power of the photovoltaic module 1 and the energy storage battery 11 according to the peak and valley state of the AC power grid 6, and controls the flexible load connected to the flexible control device 4 to restore the rated operating power.

[0108] See also Figure 3 and Figure 4 , Figure 3 [Udown, Uup] in the above is the normal operating area mentioned above, Udowm is the lower limit value of the normal operating area, Uup is the upper limit value of the normal operating area, Umin is the lower limit value of the voltage protection boundary value of the DC power supply system, Umax is the upper limit value of the voltage protection boundary value of the DC power supply system, and Ubus1 is the voltage of the DC bus 10;

[0109] like Figure 3 As shown, in the present invention, three modes are set according to whether the DC bus voltage Ubus1 is in normal operation, namely mode 1 (i.e., the first working mode), mode 2 (i.e., the second working mode), and mode 3 (i.e., the third working mode), and Figure 3 It can be seen from the flow chart that when the DC bus voltage Ubus1 is in the normal operating area, the DC power supply system operates in mode 1, and in mode 1, the AC grid, photovoltaic, energy storage and DC load maintain the existing power operation (here the AC grid is the AC grid 6 mentioned above, the photovoltaic is the photovoltaic module 1 mentioned above, and the energy storage is the energy storage battery 11 mentioned above);

[0110] In mode 2, the maximum output power of energy storage and photovoltaic is determined according to the peak and valley state of the AC power grid, and the flexible load enters the response state to reduce the operating power (that is, the flexible control device 4 in the above text determines the maximum output power of the photovoltaic module 1 and the energy storage battery 11 according to the peak and valley state of the AC power grid 6, and controls the flexible load connected to the flexible control device 4 to reduce the operating power);

[0111] In mode 3, the energy storage and photovoltaic output power are adjusted according to the peak and valley state of the AC power grid, and the flexible load restores the rated operating power (that is, the flexible control device 4 in the above text adjusts the output power of the photovoltaic module 1 and the energy storage battery 11 according to the peak and valley state of the AC power grid 6, and controls the flexible load connected to the flexible control device 4 to restore the rated operating power);

[0112] The present invention also proposes an electrical device, which has the above-mentioned DC power supply system.

[0113] Furthermore, the above-mentioned electrical equipment is an air conditioner.

[0114] Compared with the prior art, the present invention has at least the following beneficial effects:

[0115] 1. In the present invention, the electrical parameters of the DC bus are collected by a flexible control device, and the operating state of each energy storage module is adjusted according to the electrical parameters, without relying on a communication link, and the response speed is fast;

[0116] 2. The present invention can set the normal operating area of ​​the DC bus through a flexible control device, and according to whether the DC bus is in the normal operating area, control the power reduction or increase of each energy storage module to quickly achieve power balance.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A direct current power supply system, comprising a direct current bus (10), and at least one energy supply and storage module connected to the direct current bus (10), characterized in that: It also includes a flexible control device (4); The flexible control device (4) is connected to the DC bus (10) to detect electrical parameters of the DC bus (10) and set (10) a normal operating area for the DC bus; The flexible control device (4) is also connected to all the energy supply and storage modules, and is used to adjust the operating state of the energy supply and storage modules according to whether the electrical parameters are in the normal operating area.

2. The DC power supply system according to claim 1, characterized in that: The energy supply and storage module comprises a photovoltaic module (1), and a first DC / DC module (2) connecting the photovoltaic module (1) and the DC bus (10); The first DC / DC module (2) is configured as a boost topology and has at least one power switch tube, and the flexible control device (4) adjusts the output power of the first DC / DC module (2) through the power switch tube.

3. The DC power supply system according to claim 2, characterized in that: The first DC / DC module (2) comprises: a switch tube Q5, an inductor L3, a diode D1, and a capacitor C3; One end of the inductor L3 is connected to the first output end of the photovoltaic module (1), the other end of the inductor L3 is connected to the positive electrode of the diode D1, and the negative electrode of the diode D1 is connected to the flexible control device (4); The second output end of the photovoltaic module (1) is connected to the DC bus (10); one end of the switch tube Q5 as a power switch tube is connected between the inductor L3 and the diode D1; and the other end of the switch tube Q5 is connected between the second output end of the photovoltaic module (1) and the DC bus (10); One end of the capacitor C3 is connected between the diode D1 and the flexible control device (4), and the other end of the capacitor C3 is connected between the second output end of the photovoltaic module (1) and the DC bus (10).

4. The DC power supply system according to claim 1, characterized in that: The energy supply and storage module comprises an energy storage battery (11) and a second DC / DC module (9) connecting the energy storage battery (11) and the DC bus (10); The second DC / DC module (9) is a bidirectional buck-boost topology, and is used to allow electric energy to flow bidirectionally between the energy storage battery (11) and the DC bus (10).

5. The DC power supply system according to claim 4, characterized in that: The second DC / DC module includes: a switch tube Q10, a switch tube Q11, an inductor L5, a capacitor C7, and a capacitor C8; The second output end of the energy storage battery (11) is connected to the DC bus (10), the first end of the switch tube Q10 is connected to the flexible control device (4), the second end of the switch tube Q10 is connected to the first end of the switch tube Q11, and the second end of the switch tube Q11 is connected between the second output end of the energy storage battery (11) and the DC bus (10); One end of the inductor L5 is connected between the second end of the switch tube Q10 and the first end of the switch tube Q11, and the other end of the inductor L5 is connected to the first output end of the energy storage battery (11); One end of the capacitor C7 is connected between the switch tube Q10 and the flexible control device (4), and the other end of the capacitor C7 is connected between the second output end of the energy storage battery (11) and the DC bus (10); One end of the capacitor C8 is connected between the inductor L5 and the first output end of the energy storage battery (11), and the other end of the capacitor C8 is connected between the second output end of the energy storage battery (11) and the DC bus (10).

6. The DC power supply system according to claim 1, characterized in that: The energy supply and storage module comprises at least one DC load and a third DC / DC module (14) connecting the DC load and the DC bus (10); The third DC / DC module (14) is an isolation converter topology, used for converting high-voltage direct current on the direct current bus (10) into low-voltage direct current, and supplying power to the direct current load.

7. The DC power supply system according to claim 6, characterized in that: The third DC / DC module (14) comprises: a transformer T1, a switch tube Q6, a switch tube Q7, a switch tube Q8, a switch tube Q9, an inductor L4, a capacitor C4, a capacitor C5, and a capacitor C6; wherein one end of the capacitor C5 is connected to the second end of the primary side of the transformer T1, the other end of the capacitor C5 is connected to the DC bus (10), the first end of the switch tube Q6 is connected to the flexible control device (4), the second end of the switch tube Q6 is connected to the first end of the switch tube Q7, the second end of the switch tube Q7 is connected between the capacitor C5 and the DC bus (10), one end of the capacitor C4 is connected between the switch tube Q6 and the flexible control device (4), and the other end of the capacitor C4 is connected between the capacitor C5 and the DC bus (10); The secondary side of the transformer T1 adopts a winding with a center tap end, the first output end of the DC load is connected to the center tap end of the secondary side of the transformer T1, the first end of the switch tube Q9 is connected to the second end of the secondary side of the transformer T1, the second end of the switch tube Q9 is connected to the second output end of the DC load, the first end of the switch tube Q8 is connected to the first end of the secondary side of the transformer T1, and the second end of the switch tube Q8 is connected between the switch tube Q9 and the second output end of the DC load; One end of the capacitor C6 is connected between the first output end of the DC load and the center tap end of the secondary side of the transformer T1 , and the other end of the capacitor C6 is connected between the switch tube Q9 and the second output end of the DC load.

8. The DC power supply system according to claim 2, characterized in that: The energy supply and storage module comprises an AC power grid (6), and an AC / DC module (8) connecting the AC power grid (6) and the DC bus (10); The AC / DC module (8) is a bridge topology, and is used to realize bidirectional conversion between the alternating current of the alternating current grid (6) and the direct current of the direct current bus (10), and the AC / DC module (8) has at least one set of bridge arms, and the flexible control device (4) realizes output power regulation of the alternating current grid (6) by adjusting the on-off state of the switch tube on the bridge arm.

9. The DC power supply system according to claim 8, characterized in that: The energy supply and storage module includes: a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, an inductor L1, an inductor L2, a capacitor C1, a capacitor C2, a switching switch S1, and a switching switch S2; The first end of the switch tube Q1 and the first end of the switch tube Q3 are connected to the flexible control device (4), the second end of the switch tube Q2 and the second end of the switch tube Q4 are connected to the DC bus (10), the second end of the switch tube Q1 is connected to the first end of the switch tube Q2, and the second end of the switch tube Q3 is connected to the first end of the switch tube Q4; One end of the switch S1 is connected to the first output end of the AC power grid (6), and the other end of the switch S1 is connected in series with the inductor L1 and then connected between the switch tube Q1 and the switch tube Q2; One end of the switch S2 is connected to the second output end of the AC power grid (6), and the other end of the switch S2 is connected in series with the inductor L2 and then connected between the switch tube Q3 and the switch tube Q4; One end of the capacitor C1 is connected between the switch S1 and the inductor L1, the other end of the capacitor C1 is connected between the switch S2 and the inductor L2, one end of the capacitor C2 is connected between the flexible control device (4) and the connection point between the switch tube Q1 and the switch tube Q3, and the other end of the capacitor C2 is connected between the DC bus (10) and the connection point between the switch tube Q2 and the switch tube Q4.

10. The DC power supply system according to claim 9, characterized in that: The DC power supply system has three working modes, and the three working modes are set according to whether the electrical parameters are in the normal operating area; When the electrical parameter is in the normal operating range, the DC power supply system operates in a first operating mode; When the electrical parameter exceeds the lower limit of the normal operating range, the DC power supply system operates in the second operating mode; When the electrical parameter exceeds the upper limit value of the normal operating range, the DC power supply system operates in the third operating mode.

11. The DC power supply system according to claim 10, characterized in that: When the DC power supply system operates in the first working mode, the flexible control device (4) controls the photovoltaic module (1), the AC power grid (6), the energy storage battery (11), and the DC load to maintain the current power operation.

12. The DC power supply system according to claim 10, characterized in that: When the DC power supply system operates in the second working mode, the flexible control device (4) determines the maximum output power of the photovoltaic module (1) and the energy storage battery (11) according to the peak and valley state of the AC power grid (6), and controls the flexible load connected to the flexible control device (4) to reduce the operating power.

13. The DC power supply system according to claim 10, characterized in that: When the DC power supply system operates in the third working mode, the flexible control device (4) adjusts the output power of the photovoltaic module (1) and the energy storage battery (11) according to the peak and valley state of the AC power grid (6), and controls the flexible load connected to the flexible control device (4) to restore the rated operating power.

14. An electrical device, characterized in that: The electrical equipment has a DC power supply system as claimed in any one of claims 1 to 13.

15. The electrical equipment according to claim 14, characterized in that: The electrical equipment is an air conditioner.

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