CN213879294U - Micro-grid system - Google Patents
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- CN213879294U CN213879294U CN202022656286.2U CN202022656286U CN213879294U CN 213879294 U CN213879294 U CN 213879294U CN 202022656286 U CN202022656286 U CN 202022656286U CN 213879294 U CN213879294 U CN 213879294U
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Abstract
A micro-grid system comprises a grid-connected inversion unit, an alternating current and direct current bidirectional conversion unit connected with the grid-connected inversion unit in parallel and a digital signal processing control system connected with the alternating current and direct current bidirectional conversion unit; the alternating current-direct current bidirectional conversion unit inverts direct current output by the direct current power supply into alternating current according to a control signal of the digital signal processing control system, or rectifies alternating current output by the grid-connected inversion unit or the alternating current power supply into direct current. Under the coordination of a digital signal processing control system, a micro-grid system is formed by connecting an alternating current-direct current bidirectional conversion unit and a grid-connected inversion unit in parallel, so that the micro-grid system can be simultaneously integrated with various forms of power supplies such as an alternating current power supply, a direct current power supply, a new energy power generation system and the like, not only can reliably and stably supply power to an alternating current load, but also can meet diversified actual requirements by controlling a rectification time sequence and an inversion time sequence of the alternating current-direct current bidirectional conversion unit by using the digital signal processing control system.
Description
Technical Field
The utility model relates to an electric power electric wire netting technical field, concretely relates to little grid system.
Background
With the continuous expansion of the power grid scale, a super-large interconnected network system for centralized power generation and remote power transmission is developed gradually. However, due to the continuous increase of long-distance power transmission, the dependence degree of a front-end power grid on external power is continuously improved, the stability and the safety of power grid operation tend to be reduced, and diversified power supply requirements are difficult to meet. On the other hand, concerns about problems such as gradual depletion of global conventional energy sources, environmental pollution, and the like are becoming more and more prominent. In view of this, environmentally friendly, efficient and flexible microgrid systems are widely favored.
The existing micro-grid system mainly comprises a grid-connected inverter power supply and an off-grid inverter power supply, and under a common condition, the micro-grid is connected with a mains supply power grid so as to ensure the stability and reliability of system power supply. However, most of the existing off-grid inverter power supplies only have a single load power supply function, and the grid-connected inverter power supplies have the characteristic of high power supply fluctuation, so that once the problems of power failure of the mains supply, insufficient electric quantity stored in the off-grid inverter power supplies and the like occur, a plurality of problems such as grid faults, unstable load power supply, reduced electric energy quality and the like are easily caused, and the power utilization safety is influenced.
SUMMERY OF THE UTILITY MODEL
The utility model discloses the main technical problem who solves provides a little grid system to reach the purpose that improves little grid system reliability of operation.
An embodiment provides a microgrid system comprising:
the alternating current-direct current bidirectional conversion unit is used for rectifying alternating current into direct current to be output or converting the direct current into alternating current to be output according to a received control signal, and is provided with an alternating current end, a direct current end and a control end, wherein the direct current end is used for being connected with a direct current power supply, and the alternating current end is used for being connected with an input end of an alternating current load and an output end of the alternating current power supply;
the grid-connected inversion unit is provided with a grid-connected input end and a grid-connected output end, the grid-connected input end is used for connecting a new energy power generation system, the grid-connected output end is connected with an alternating current end, the grid-connected output end is used for the input end of an alternating current load and the output end of an alternating current power supply, and the grid-connected output end, the alternating current end and the output end of the alternating current power supply are connected in parallel at the input end of the alternating current load; and
and the digital signal processing control system is connected with the control end and used for sending a control signal to the alternating current-direct current bidirectional conversion unit according to the state information of the alternating current power supply and/or the state information of the direct current power supply so as to control the rectification time sequence or the inversion time sequence of the alternating current-direct current bidirectional conversion unit.
In one embodiment, the power supply further comprises an isolation transformation unit, the isolation transformation unit is connected between the alternating current end and the grid-connected output end, and the isolation transformation unit is used for connecting the input end of the alternating current load and the output end of the alternating current power supply.
In one embodiment, the isolation transformation unit comprises a power frequency transformer, and the power frequency transformer comprises:
the secondary side coil is connected with the grid-connected output end and is used for the input end of an alternating current load and the output end of an alternating current power supply; and
the primary coil is provided with a first connecting end and a second connecting end, and the first connecting end and the second connecting end are respectively connected with an alternating current end.
In one embodiment, the ac-dc bidirectional conversion unit includes:
the first controllable switch is provided with a control end and two current conducting ends, the control end of the first controllable switch is connected with the digital signal processing control system, and the two current conducting ends of the first controllable switch are respectively used as a direct current end to be connected with the anode of the direct current power supply and used as an alternating current end to be connected with the second connecting end;
the second controllable switch is provided with a control end and two current conducting ends, the control end of the second controllable switch is connected with the digital signal processing control system, and the two current conducting ends of the second controllable switch are respectively used as a direct current end to be connected with the anode of the direct current power supply and used as an alternating current end to be connected with the first connecting end;
the third controllable switch is provided with a control end and two current conducting ends, the control end of the third controllable switch is connected with the digital signal processing control system, and the two current conducting ends of the third controllable switch are respectively used as a direct current end to be connected with the negative electrode of the direct current power supply and used as an alternating current end to be connected with the second connecting end; and
the control end of the fourth controllable switch is connected with the digital signal processing control system, and the two current conduction ends of the fourth controllable switch are respectively used as a direct current end to be connected with the negative electrode of the direct current power supply and used as an alternating current end to be connected with the first connection end;
the digital signal processing control system periodically switches the on-state and the off-state of the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch through the control end of each controllable switch so as to control the rectification time sequence or the inversion time sequence of the alternating current-direct current bidirectional conversion unit.
In one embodiment, the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch are all field effect transistors with single-pass diodes.
In one embodiment, the device further comprises a detection unit, wherein the detection unit is connected with the digital signal processing control system, the detection unit is used for detecting and outputting the state information of the alternating current power supply and/or is used for detecting and outputting the state information of the direct current power supply, the state information of the alternating current power supply comprises the voltage information of the alternating current power supply, and the state information of the direct current power supply comprises the voltage information of the direct current power supply;
the digital signal processing control system is used for sending a control signal to the alternating current-direct current bidirectional conversion unit according to the signal output by the detection unit so as to control the rectification time sequence or the control time sequence of the alternating current-direct current bidirectional conversion unit.
In one embodiment, the new energy power generation system is a solar photovoltaic power generation system or a wind power generation system.
In one embodiment, the system further comprises a human-computer interaction unit, the human-computer interaction unit is connected with the digital signal processing control system, the human-computer interaction unit comprises an input module, the input module is used for inputting preset information and outputting the preset information to the digital signal processing control system, and the preset information comprises voltage specification information of the alternating current power supply and voltage specification information of the direct current power supply.
In one embodiment, the human-computer interaction unit further comprises a display module, and the display module is used for receiving and displaying information output by the digital signal processing control system.
The microgrid system comprises a grid-connected inversion unit, an alternating current-direct current bidirectional conversion unit connected with the grid-connected inversion unit in parallel and a digital signal processing control system connected with the alternating current-direct current bidirectional conversion unit; the alternating current-direct current bidirectional conversion unit inverts direct current output by the direct current power supply into alternating current according to a control signal of the digital signal processing control system, or rectifies alternating current output by the grid-connected inversion unit or the alternating current power supply into direct current. Under the coordination of a digital signal processing control system, a micro-grid system is formed by connecting an alternating current-direct current bidirectional conversion unit and a grid-connected inversion unit in parallel, so that the micro-grid system can be simultaneously integrated with various forms of power supplies such as an alternating current power supply, a direct current power supply, a new energy power generation system and the like, not only can reliably and stably supply power to an alternating current load, but also can meet diversified actual requirements by controlling a rectification time sequence and an inversion time sequence of the alternating current-direct current bidirectional conversion unit by using the digital signal processing control system.
Drawings
Fig. 1 is a schematic structural diagram (one) of a microgrid system according to an embodiment;
fig. 2 is a schematic structural diagram of a microgrid system according to an embodiment (ii);
fig. 3 is a system schematic block diagram (one) of a microgrid system of an embodiment;
fig. 4 is a system schematic block diagram of a microgrid system according to an embodiment (ii).
Detailed Description
The present application will be described in further detail below with reference to the accompanying drawings by way of specific embodiments. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.
Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.
The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).
The micro-grid system mainly aims at the problems that the existing off-grid inverter cannot be well suitable for the micro-grid system due to the fact that the existing off-grid inverter only has a single power supply function, and the grid-connected power generation system is easy to influence the reliability of the grid system due to unstable power supply and the like.
Referring to fig. 1 and 3, in an embodiment, a microgrid system is provided, which includes a Digital Signal processing control system 10 (i.e., a Digital Signal Process, DSP), an isolation transformer unit 20, an ac/dc bidirectional conversion unit 30, and a grid-connected inverter unit 40, which are described below.
The digital signal processing control system 10 is connected to the ac-dc bidirectional conversion unit 30, and is used as a core control system of the ac-dc bidirectional conversion unit 30; the AC-DC bidirectional conversion circuit is mainly used for sending a control signal to the AC-DC bidirectional conversion unit 30 according to the state information of the AC power supply A and/or the state information of the DC power supply B, controlling the rectification time sequence (namely, rectifying and converting the obtained AC into DC and outputting) or the inversion time sequence (namely, inverting and converting the obtained DC into AC and outputting) of the AC-DC bidirectional conversion unit 30, and realizing the AC-DC bidirectional conversion function of the AC-DC bidirectional conversion unit 30; meanwhile, the frequency control circuit can also be used for controlling the frequency of the alternating current output by the alternating current-direct current bidirectional conversion unit 30 according to the state information of the direct current power supply B.
In this embodiment, the ac power supply a may be a commercial power supply system, and the dc power supply B may be a power supply system composed of an existing energy storage battery and an associated charge and discharge management system; the state information of the ac power supply a and the state information of the dc power supply B include, but are not limited to, output voltage information, output current information, comparison information formed by comparing the output voltage information and/or output current information with corresponding threshold information, power information formed by converting the output voltage information and/or output current information, and the like.
In this embodiment, please refer to fig. 1 and 3, the isolation transforming unit 20 includes a power frequency transformer, the power frequency transformer includes a secondary coil 21 and a primary coil 22, the secondary coil 21 is connected to the output end of the grid-connected inverting unit 30 and is used for connecting the output end of the ac power supply a and the input end of the ac load D, and the secondary coil 21, the output end of the ac power supply a and the output end of the grid-connected inverting unit 30 are connected in parallel to the input end of the ac load D; the primary winding 22 has a first connection end 221 and a second connection end 222, and the ac-dc bidirectional conversion unit 30 is connected by the first connection end 221 and the second connection end 222. It can be understood that: since the ac/dc bidirectional conversion unit 30 has the conversion functions of inversion and rectification, the secondary winding 21 and the primary winding 22 are a relative concept, which only represents two different windings of the industrial frequency transformer.
Referring to fig. 1 and fig. 3, the ac-dc bi-directional converting unit 30 has an ac terminal 31, a dc terminal 32 and a control terminal 33; the alternating current end 31 is connected with the primary coil 22 of the isolation transformation unit 20, and is connected with the output end of the grid-connected inversion unit 40, the output end of the alternating current power supply A and the input end of the alternating current load D through the secondary coil 21 of the isolation transformation unit 20, so that the alternating current-direct current bidirectional conversion unit 30, the grid-connected inversion unit 40 and the alternating current power supply A are connected in parallel at the input end of the alternating current load D; the dc terminal 32 is used for connecting a dc power supply B, and the control terminal 33 is connected to the digital signal processing control system 10, so as to receive a control signal sent by the digital signal processing control system 10, rectify and convert the ac power output by the ac power supply a and/or the grid-connected inverter unit 40 into dc power and output the dc power to the dc power supply B, thereby achieving the purpose of charging the dc power supply B, or convert the dc power output by the dc power supply B into ac power and then incorporate the ac power into a power supply network of an ac load D, thereby achieving the purpose of supplying power to the ac load D.
In one embodiment, referring to fig. 1, the ac/dc bi-directional converting unit 30 includes a first controllable switch S1, a second controllable switch S2, a third controllable switch S3 and a fourth controllable switch S4, wherein the first controllable switch S1, the second controllable switch S2, the third controllable switch S3 and the fourth controllable switch S4 are all N-channel fets with single-pass diodes, and each have a control terminal (i.e., gate G) and two current conducting terminals (i.e., drain D and source S). Wherein:
the gate G of the first controllable switch S1 is connected to the digital signal processing control system 10, the drain D is connected to the positive electrode of the dc power supply B as the dc terminal 32, and the source S is connected to the second connection terminal 222 as the ac terminal 31;
a grid G of the second controllable switch S2 is connected with the digital signal processing control system 10, a drain D is used as a direct current end 32 to be connected with the anode of the direct current power supply B, and a source S is used as an alternating current end 31 to be connected with the first connection end 221;
the gate G of the third controllable switch S3 is connected to the digital signal processing control system 10, the source S is connected to the negative electrode of the dc power supply B as the dc terminal 32, and the drain D is connected to the second connection terminal 222 as the ac terminal 31;
the gate G of the fourth controllable switch S4 is connected to the digital signal processing control system 10, the source S is connected to the negative terminal of the dc power supply B as the dc terminal 32, and the drain D is connected to the first connection terminal 221 as the ac terminal 31.
The digital signal processing control system 10 periodically switches the on-state and the off-state of the first controllable switch S1, the second controllable switch S2, the third controllable switch S3 and the fourth controllable switch S4 through the control end of each controllable switch, so as to implement the rectification timing sequence or the inversion timing sequence of the ac/dc bidirectional conversion unit 30. It should be noted that the rectification timing and the inversion timing of the ac-dc bidirectional conversion unit 30 composed of the four controllable switches are well known in the art, and the current direction can be converted by periodically adjusting the on-off states of the first controllable switch S1 and the fourth controllable switch S4 (or the second controllable switch S2 and the third controllable switch S3) to convert the current, so as to invert the dc current into the ac current, or rectify the ac current into the dc current; specifically, taking the digital signal processing control system 10 as an example to control the inversion timing sequence of the ac-dc bidirectional conversion unit 30, in a period, the digital signal processing control system 10 controls the first controllable switch S1 and the fourth controllable switch S4 to be turned on, the second controllable switch S2 and the third controllable switch S3 to be turned off, and then controls the second controllable switch S2 and the third controllable switch S3 to be turned on, and the first controllable switch S1 and the fourth controllable switch S4 to be turned off; and the process of inverting and converting the direct current into the alternating current can be realized by sequentially carrying out cyclic switching of a plurality of periods. Since the inversion timing and the rectification timing of this part belong to the prior art, they will not be described in detail herein, and the waveform state (such as sine wave, PWM wave, SPWM wave) of the enable signal sent by the adopted digital signal processing control system 10 to the control terminal of each controllable switch is not limited.
Of course, in other embodiments, the first controllable switch S1, the second controllable switch S2, the third controllable switch S3, and the fourth controllable switch S4 may be relays, other electronic switches, and combinations thereof.
In another embodiment, referring to fig. 2, on the basis of the first controllable switch S1, the second controllable switch S2, the third controllable switch S3 and the fourth controllable switch S4, the ac-dc bidirectional conversion unit 30 further includes a fifth controllable switch S5 and a sixth controllable switch S6, the fifth controllable switch S5 and the sixth controllable switch S6 also employ N-channel fets with single-pass diodes, and both have a control terminal (i.e., gate G) and two current-conducting terminals (i.e., drain D and source S); the gate G of the fifth controllable switch S5 and the gate G of the sixth controllable switch S6 are respectively connected to the digital signal processing control system 10, the drain D of the fifth controllable switch S5 is connected to the source S of the sixth controllable switch S6 and the drain D of the first controllable switch S1, the source S of the fifth controllable switch S5 is connected to the negative electrode of the dc power supply B, and the drain D of the first controllable switch S1 and the drain D of the fifth controllable switch S5 are simultaneously connected to the positive electrode of the dc power supply B through the drain D of the sixth controllable switch S6. Therefore, by adding the fifth controllable switch S5 and the sixth controllable switch S6, an SPWM waveform can be formed in the inversion timing sequence of the ac-dc bidirectional conversion unit 30, thereby effectively reducing the loss of the fet; in the rectification sequence, the loss of the field effect transistor can be reduced, and the output characteristic of the direct current side can be improved.
The grid-connected inverter unit 40 may adopt an existing grid-connected inverter suitable for the new energy power generation system E, and is mainly used for incorporating the electric energy generated by the new energy power generation system E into the power supply of the ac load D to realize the power supply of the ac load D or charge the dc power supply B through the action of the ac-dc bidirectional conversion unit 30. The grid-connected inverter unit 40 has a grid-connected input end 41 and a grid-connected output end 42, the grid-connected input end 41 is used for connecting the new energy power generation system E, and the grid-connected output end 42, the secondary coil 21 and the output end of the alternating current power supply a are connected in parallel to the input end of the alternating current load D. In this embodiment, the new energy power generation system E may be a solar photovoltaic power generation system or a wind power generation system.
On one hand, under the coordination of the digital signal processing control system 10 and the isolation transformation unit 20, the microgrid system is formed by connecting the alternating current-direct current bidirectional transformation unit 30 and the grid-connected inversion unit 40 in parallel, so that the microgrid system can be simultaneously integrated with various different forms of power supplies such as an alternating current power supply A, a direct current power supply B, a new energy power generation system E and the like, not only can reliably and stably supply power to an alternating current load D, but also can meet diversified actual requirements by utilizing the relationship between the digital signal processing control system 10 and the alternating current-direct current bidirectional transformation unit 30; the method specifically comprises the following steps:
1. when the ac power supply a supplies power normally, the digital signal processing control system 10 can control the ac-dc bidirectional conversion unit 30 to invert the dc power output by the dc power supply B into ac power according to the state information of the ac power supply a at this time, and simultaneously, the ac power output by the grid-connected inversion unit 40 and the ac power output by the ac power supply a are merged into the power supply network of the ac load D to supply power to the ac load D at the same time; the digital signal processing control system 10 can control the ac-dc bidirectional conversion unit 30 to obtain power from the ac power supply a and/or the grid-connected inverter unit 40 according to the state information of the dc power supply B (for example, the storage battery is in a negative power state, an insufficient power state, etc.), so as to rectify and convert the obtained ac power into dc power, thereby charging the dc power supply B.
2. When the alternating current power supply A has a fault or is disconnected, the digital signal processing control system 10 can control the rectification time sequence or the inversion time sequence of the alternating current-direct current bidirectional conversion unit 30 according to the state information of the alternating current power supply A, the actual power information of the alternating current load D carried by the microgrid system, the rated power information of the grid-connected inversion unit 40 and the like; such as: when the rated power of the grid-connected inverter unit 40 is smaller than the actual power of the alternating current load D carried by the microgrid system, the alternating current-direct current bidirectional conversion unit 30 is controlled to invert the direct current output by the direct current power supply B into alternating current, and the alternating current output by the grid-connected inverter unit 40 are merged into a power supply network of the alternating current load D to supply power to the alternating current load D at the same time. When the rated power of the grid-connected inverter unit 40 is smaller than the actual power of the alternating current load D carried by the microgrid system and the direct current power supply B is in a negative power state, the alternating current-direct current bidirectional conversion unit 30 can be controlled to take power from the grid-connected inverter unit 40 so as to rectify and convert the obtained alternating current into direct current to charge the direct current power supply B; meanwhile, when the dc power supply B is over-voltage or over-current, the ac/dc bi-directional converting unit 30 may be controlled to adjust the output frequency (e.g., increase or decrease) to cut off the grid-connected inverting unit 40.
On the other hand, on the basis of the traditional off-grid inverter, the alternating current-direct current bidirectional conversion unit 30 formed under the coordination of the digital signal processing control system 10 has the function of alternating current-direct current bidirectional conversion according to the actual situation when the microgrid system is applied, and the problem that the normal operation of the microgrid system is easily influenced when the phenomena of power failure, insufficient power quantity and the like occur when the traditional off-grid inverter only has a single power supply function when the traditional off-grid inverter is applied to the microgrid system is effectively solved.
In some embodiments, under the condition that the microgrid system has other safe application capabilities, the isolation transformation unit 20 may also be omitted, and the ac end of the ac-dc bidirectional conversion unit 30 is directly connected in parallel with the grid-connected inverter unit 30 and the ac power supply a at the input end of the ac load D, which is beneficial to reducing the configuration number of electronic components of the system and reducing the configuration cost and the structural complexity of the system.
Referring to fig. 4, an embodiment provides a microgrid system, further including a detection unit 50, where the detection unit 50 is connected to the digital signal processing control system 10, and is mainly used for detecting and outputting status information of an ac power supply a and/or for detecting and outputting status information of a dc power supply B, so that the digital signal processing control system 10 can control an inversion timing sequence or a rectification timing sequence of the ac-dc bidirectional conversion unit 30 according to information output by the detection unit 50; the state information of the ac power supply a and the state information of the dc power supply B are already described in the foregoing embodiments, and therefore are not described herein again. It should be noted that, the specific circuit structure of the detecting unit 50 may be selectively configured by referring to related circuits capable of implementing detecting functions of items such as voltage, current, power, and the like in the prior art, and details thereof are not repeated here.
Referring to fig. 4, an embodiment provides a microgrid system, further including a human-computer interaction module 60 connected to the digital signal processing control system 10, where the human-computer interaction module 60 includes an input module for inputting preset information, where the preset information includes, but is not limited to, power information of an ac load D carried by the microgrid system, rated power information of the grid-connected inverter unit 40, output voltage/current information of the ac power supply a, power information of the dc power supply B, and related voltage, current, power and other thresholds, etc.; the input module can be a keyboard, an operation button and the like, and when the input module is the keyboard or the operation button, a user can directly input required preset information through the input module. In this embodiment, the human-computer interaction module 60 may automatically send the information input by the user to the digital signal processing control system 10, or the digital signal processing control system 10 reads the information input by the input module in real time or at regular time, and after receiving the corresponding information, the digital signal processing control system 10 analyzes and processes the information, and then controls the inversion timing sequence or the rectification timing sequence of the ac-dc bidirectional conversion unit 30 according to the analysis result.
In one embodiment, the human-computer interaction module 60 further includes a display module, and the input module may also be a mouse, a keyboard, or a touch screen integrated with the display module, and when the input module is a mouse, a keyboard, or a touch screen, a user may combine the input module with a soft keyboard, an operation icon, a tab, a menu option, or the like on the display module to complete input of preset information. The display module can be used for displaying information input by the input module, information output by the digital signal processing control system 10, time sequence state information of the alternating current-direct current bidirectional conversion unit 30, running state information of the microgrid system, related fault information and the like, and can also be used for giving an alarm prompt.
It is right to have used specific individual example above the utility model discloses expound, only be used for helping to understand the utility model discloses, not be used for the restriction the utility model discloses. To the technical field of the utility model technical personnel, the foundation the utility model discloses an idea can also be made a plurality of simple deductions, warp or replacement.
Claims (9)
1. A microgrid system, comprising:
the alternating current-direct current bidirectional conversion unit is used for rectifying alternating current into direct current to be output or converting the direct current into alternating current to be output according to a received control signal, and is provided with an alternating current end, a direct current end and a control end, wherein the direct current end is used for being connected with a direct current power supply, and the alternating current end is used for being connected with an input end of an alternating current load and an output end of the alternating current power supply;
the grid-connected inversion unit is provided with a grid-connected input end and a grid-connected output end, the grid-connected input end is used for connecting a new energy power generation system, the grid-connected output end is connected with an alternating current end, the grid-connected output end is used for the input end of an alternating current load and the output end of an alternating current power supply, and the grid-connected output end, the alternating current end and the output end of the alternating current power supply are connected in parallel at the input end of the alternating current load; and
and the digital signal processing control system is connected with the control end and used for sending a control signal to the alternating current-direct current bidirectional conversion unit according to the state information of the alternating current power supply and/or the state information of the direct current power supply so as to control the rectification time sequence or the inversion time sequence of the alternating current-direct current bidirectional conversion unit.
2. The microgrid system of claim 1, further comprising an isolation transformation unit connected between the ac terminals and the grid-tied output terminals, the isolation transformation unit being configured to connect the input terminals of the ac loads and the output terminals of the ac power source.
3. The microgrid system of claim 2, wherein the isolation transformation unit comprises a power frequency transformer, the power frequency transformer comprising:
the secondary side coil is connected with the grid-connected output end and is used for the input end of an alternating current load and the output end of an alternating current power supply; and
the primary coil is provided with a first connecting end and a second connecting end, and the first connecting end and the second connecting end are respectively connected with an alternating current end.
4. The microgrid system of claim 3, wherein the alternating current-direct current bidirectional conversion unit comprises:
the first controllable switch is provided with a control end and two current conducting ends, the control end of the first controllable switch is connected with the digital signal processing control system, and the two current conducting ends of the first controllable switch are respectively used as a direct current end to be connected with the anode of the direct current power supply and used as an alternating current end to be connected with the second connecting end;
the second controllable switch is provided with a control end and two current conducting ends, the control end of the second controllable switch is connected with the digital signal processing control system, and the two current conducting ends of the second controllable switch are respectively used as a direct current end to be connected with the anode of the direct current power supply and used as an alternating current end to be connected with the first connecting end;
the third controllable switch is provided with a control end and two current conducting ends, the control end of the third controllable switch is connected with the digital signal processing control system, and the two current conducting ends of the third controllable switch are respectively used as a direct current end to be connected with the negative electrode of the direct current power supply and used as an alternating current end to be connected with the second connecting end; and
the control end of the fourth controllable switch is connected with the digital signal processing control system, and the two current conduction ends of the fourth controllable switch are respectively used as a direct current end to be connected with the negative electrode of the direct current power supply and used as an alternating current end to be connected with the first connection end;
the digital signal processing control system periodically switches the on-state and the off-state of the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch through the control end of each controllable switch so as to control the rectification time sequence or the inversion time sequence of the alternating current-direct current bidirectional conversion unit.
5. The microgrid system of claim 4, wherein the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch are field effect transistors with single pass diodes.
6. The microgrid system of claim 1, further comprising a detection unit connected with the digital signal processing control system, wherein the detection unit is used for detecting and outputting status information of an alternating current power supply and/or is used for detecting and outputting status information of a direct current power supply, the status information of the alternating current power supply comprises voltage information of the alternating current power supply, and the status information of the direct current power supply comprises voltage information of the direct current power supply;
the digital signal processing control system is used for sending a control signal to the alternating current-direct current bidirectional conversion unit according to the signal output by the detection unit so as to control the rectification time sequence or the control time sequence of the alternating current-direct current bidirectional conversion unit.
7. The microgrid system of claim 1, wherein the new energy power generation system is a solar photovoltaic power generation system or a wind power generation system.
8. The microgrid system of claim 1, further comprising a human-machine interaction unit connected with the digital signal processing control system, wherein the human-machine interaction unit comprises an input module for inputting preset information and outputting the preset information to the digital signal processing control system, and the preset information comprises voltage specification information of the alternating current power supply and voltage specification information of the direct current power supply.
9. The microgrid system of claim 8, wherein the human-computer interaction unit further comprises a display module for receiving and displaying information output by the digital signal processing control system.
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