Multi-port converter and charging system

Abstract

The invention relates to a multi-port converter and a charging system. At least two input assemblies are arranged in the multi-port converter, the input end of each input assembly is used for being connected with a photovoltaic assembly, the output end of each input assembly is coupled with the corresponding primary side coil so that photovoltaic voltage can be boosted and transmitted to the output assembly through the transformer, and the output assembly is used for receiving alternating current voltage output by the transformer and transmitting the alternating current voltage to the output assembly. The alternating-current voltage is rectified and stabilized, and the processed direct-current voltage is respectively output to the energy storage equipment and the charging equipment through a direct-current bus; the multi-port converter provided by the embodiment of the invention can be directly connected with a photovoltaic module, the utilization of photovoltaic voltage can be realized without arranging an inverter, and the cost required for utilizing a photovoltaic power supply is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic power generation, and in particular to a multi-port converter and a charging system. Background Art

[0002] At present, the existing Z-source converter needs to invert the photovoltaic voltage through the SPFL (Single-Phase Five-Level) inverter, and then input the obtained AC power into the single-phase distribution network for application.

[0003] However, the existing SPFL inverter uses many components and has a complex circuit structure, which leads to a high cost when using photovoltaic power. Summary of the invention

[0004] Based on this, it is necessary to provide a multi-port converter and charging system that can reduce the cost required when utilizing photovoltaic power sources in order to address the above technical problems.

[0005] In a first aspect, the present application provides a multi-port converter, comprising:

[0006] A transformer, comprising a secondary coil and at least two primary coils;

[0007] At least two input components, the input end of the input component is used to connect to the photovoltaic component, the output end of the input component is coupled to the primary coil, and the input component is used to boost the photovoltaic voltage received from the photovoltaic component output; wherein the same-named end of the primary coil coupled to the output end of any input component is opposite to the same-named end of the primary coil coupled to the output end of another input component, the same-named end of the primary coil coupled to the output end of any input component is the same as the same-named end of the secondary coil, and the same-named end of the primary coil coupled to the output end of another input component is opposite to the same-named end of the secondary coil;

[0008] An output component, the input end of the output component is coupled with the secondary coil, and the output end of the output component is connected to the energy storage device and the charging device respectively through the DC bus. The output component is used to receive the AC voltage output by the transformer, rectify and stabilize the AC voltage, and output the processed DC voltage to the energy storage device and the charging device respectively through the DC bus.

[0009] In one embodiment, the input component includes:

[0010] A boost unit, one end of which is used to connect to the output end of the photovoltaic module;

[0011] A first switch tube, wherein the drain of the first switch tube is connected to the other end of the boost unit, and the source of the first switch tube is respectively connected to one end of the primary coil and the input end of the photovoltaic module;

[0012] An output diode, wherein the anode of the output diode is respectively connected to the drain of the first switch tube and the other end of the boost unit, and the cathode of the output diode is connected to the other end of the primary coil.

[0013] In one embodiment, the boost unit comprises:

[0014] A first inductor, one end of which is connected to an output end of the photovoltaic module;

[0015] A first capacitor, one end of which is connected to the output end of the photovoltaic module;

[0016] A second capacitor, one end of the second capacitor is connected to the other end of the first inductor, and the other end of the second capacitor is respectively connected to the drain of the first switch tube and the anode of the output diode;

[0017] A second inductor, one end of the second inductor is connected to the other end of the first capacitor, and the other end of the second inductor is respectively connected to the drain of the first switch tube and the anode of the output diode;

[0018] A first diode, wherein an anode of the first diode is connected between the other end of the first inductor and one end of the second capacitor, and a cathode of the first diode is connected between the other end of the first capacitor and one end of the second inductor.

[0019] In one embodiment, the output component includes:

[0020] An output unit, wherein a first end of the output unit is connected to one end of the secondary coil, and a second end of the output unit is connected to the other end of the secondary coil;

[0021] a second switch tube, wherein a drain of the second switch tube is connected to the first end of the output unit, and a source of the second switch tube is connected to the DC bus;

[0022] a third switch tube, wherein the drain of the third switch tube is connected to the second end of the output unit, and the source of the third switch tube is respectively connected to the source of the second switch tube and the DC bus;

[0023] a second diode, wherein an anode of the second diode is connected to the third end of the output unit, and a cathode of the second diode is connected to the DC bus;

[0024] A third diode, wherein an anode of the third diode is connected to the fourth end of the output unit, and a cathode of the third diode is connected to the cathode of the second diode and the DC bus respectively.

[0025] In one embodiment, the second switch tube and the third switch tube are both N-type MOS tubes.

[0026] In one embodiment, the output unit includes:

[0027] a fourth diode, wherein an anode of the fourth diode is connected to the drain of the third switch tube, and a cathode of the fourth diode is connected to the anode of the second diode;

[0028] a third capacitor, one end of the third capacitor being connected to the cathode of the fourth diode and the anode of the third diode respectively, and the other end of the third capacitor being connected to the drain of the second switch tube;

[0029] a fifth diode, wherein an anode of the fifth diode is respectively connected to the other end of the third capacitor, one end of the secondary coil and the drain of the second switch tube, and a cathode of the fifth diode is connected to the anode of the third diode;

[0030] A fourth capacitor, one end of the fourth capacitor is respectively connected to the cathode of the fifth diode and the anode of the third diode, and the other end of the fourth capacitor is respectively connected to the anode of the fourth diode, the other end of the secondary coil and the drain of the third switch tube.

[0031] In one embodiment, the multi-port converter includes a first operating mode and a second operating mode in one switching cycle.

[0032] In one embodiment, when the multi-port converter is in the first working mode, the third switch tube is turned on.

[0033] In one embodiment, when the multi-port converter is in the second working mode, the second switch tube is turned on.

[0034] In a second aspect, the present application further provides a charging system, comprising a control module, a driving module connected to the control module, and a multi-port converter as described above connected to the driving module; wherein:

[0035] The driving module is respectively connected to the gate of the first switch tube, the gate of the second switch tube and the gate of the third switch tube, and the control module is used to connect the energy storage device, the photovoltaic component and the charging device.

[0036] The above-mentioned multi-port converter and charging system are provided with at least two input components in the multi-port converter, the input end of each input component is used to connect to the photovoltaic component, and the output end of each input component is coupled with each primary coil respectively to boost the photovoltaic voltage and transmit it to the output component through the transformer. The output component is used to receive the AC voltage output by the transformer, rectify and stabilize the AC voltage, and output the processed DC voltage to the energy storage device and the charging device respectively through the DC bus; the multi-port converter provided in the embodiment of the present application can be directly connected to the photovoltaic component, and the photovoltaic voltage can be utilized without setting up an inverter, thereby reducing the cost required for utilizing the photovoltaic power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 is a schematic structural diagram of a multi-port converter in one embodiment;

[0039] Figure 2 is a schematic structural diagram of a multi-port converter in another embodiment;

[0040] Figure 3 is a current schematic diagram of a multi-port converter in a first working mode in an embodiment;

[0041] Figure 4 is a current schematic diagram of a multi-port converter in a second working mode in one embodiment;

[0042] Figure 5 It is a schematic diagram of a flow chart of a control module determining an operating mode of a charging system in an embodiment. DETAILED DESCRIPTION

[0043] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] It is understood that the terms "first", "second", etc. used in this application can be used to describe various elements in this article, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first capacitor can be referred to as a second capacitor, and similarly, a second capacitor can be referred to as a first capacitor. Both the first capacitor and the second capacitor are capacitors, but they are not the same capacitor.

[0046] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0047] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0048] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0049] The existing SPFL inverter part uses too many components, such as inductors, capacitors, switches and diodes, which greatly increases the complexity and cost of the charging system. There is a problem of high cost when using photovoltaic power sources. At the same time, the parasitic resistance generated by the components may generate harmonics and electromagnetic interference, thereby affecting the efficiency and dynamic performance of the charging system, resulting in power loss in the circuit, thereby reducing the overall conversion efficiency.

[0050] The multi-port converter provided in the embodiment of the present application is provided with at least two input components in the multi-port converter, the input end of each input component is used to connect to the photovoltaic component, the output end of each input component is respectively coupled with each primary coil to boost the photovoltaic voltage and transmit it to the output component through the transformer, the output component is used to receive the AC voltage output by the transformer, and rectify and stabilize the AC voltage, and output the processed DC voltage to the energy storage device and the charging device through the DC bus, respectively. The photovoltaic voltage can be utilized without setting up an inverter, thereby reducing the cost required for utilizing the photovoltaic power supply. At the same time, the energy loss caused by the conversion is reduced, and the overall efficiency is improved.

[0051] In an exemplary embodiment, Figure 1 As shown, a multi-port converter is provided, comprising:

[0052] A transformer, comprising a secondary coil and at least two primary coils;

[0053] At least two input components, the input end of the input component is used to connect to the photovoltaic component, the output end of the input component is coupled to the primary coil, and the input component is used to boost the photovoltaic voltage received from the photovoltaic component output; wherein the same-named end of the primary coil coupled to the output end of any input component is opposite to the same-named end of the primary coil coupled to the output end of another input component, the same-named end of the primary coil coupled to the output end of any input component is the same as the same-named end of the secondary coil, and the same-named end of the primary coil coupled to the output end of another input component is opposite to the same-named end of the secondary coil;

[0054] An output component, the input end of the output component is coupled with the secondary coil, and the output end of the output component is connected to the energy storage device and the charging device respectively through the DC bus. The output component is used to receive the AC voltage output by the transformer, rectify and stabilize the AC voltage, and output the processed DC voltage to the energy storage device and the charging device respectively through the DC bus.

[0055] Among them, photovoltaic components refer to components that can obtain photovoltaic power, such as photovoltaic panels; energy storage devices refer to devices used for energy storage, such as batteries; charging devices refer to devices used for charging and discharging, such as DC charging piles.

[0056] Specifically, if Figure 1 As shown, the photovoltaic component is connected to the energy storage device and the charging device respectively through the multi-port converter and the DC bus, that is, the photovoltaic component, the energy storage device and the charging device can exchange energy through the multi-port converter and the DC bus, wherein the input component boosts the received photovoltaic voltage and outputs it to the transformer, the output component receives the AC voltage output by the transformer, rectifies and stabilizes the AC voltage, and outputs the processed DC voltage to the energy storage device and the charging device respectively through the DC bus, exchanges energy with the energy storage device, and provides stable DC power for the charging device.

[0057] For example, Figure 1 As shown, by setting the same-named end of the primary coil coupled to the output end of any input component (the primary coil corresponding to Vp1) and the same-named end of the primary coil coupled to the output end of another input component to be opposite (the primary coil corresponding to Vp2), the same-named end of the primary coil coupled to the output end of any input component (the primary coil corresponding to Vp1) and the same-named end of the secondary coil (the secondary coil corresponding to Vsec) are the same, and the same-named end of the primary coil coupled to the output end of another input component (the primary coil corresponding to Vp2) and the same-named end of the secondary coil (the secondary coil corresponding to Vsec) are opposite, so that the transformer can output an AC voltage.

[0058] It should be noted that the number of input components can be set according to actual conditions, and the number of primary coils can be equal to the number of input components.

[0059] The photovoltaic power generation technology (photovoltaic modules) is linked with the energy storage system (energy storage equipment) and the charging pile (charging equipment) to realize the integration of light storage and charging. The more direct application of photovoltaic power generation reduces the intermediate links (inverter), improves the utilization efficiency of photovoltaic power, and reduces the cost required for the use of photovoltaic power. At the same time, the photovoltaic power generation system is connected with the energy storage system and the charging pile system through a multi-port converter and a DC bus. The main function of the energy storage system is to smooth the power output, cut the peak and fill the valley, thereby improving the power supply reliability and optimizing the energy configuration. The charging pile system adopts a DC charging pile. The stable DC voltage obtained by the photovoltaic module through the input component (Z impedance network) and the transformer and output component (rectifier circuit) can directly power the charging pile, which improves the efficiency of the charging system.

[0060] The above-mentioned multi-port converter is provided with at least two input components in the multi-port converter, the input end of each input component is used to connect the photovoltaic component, the output end of each input component is coupled with each primary coil respectively to boost the photovoltaic voltage and transmit it to the output component through the transformer, the output component is used to receive the AC voltage output by the transformer, and rectify and stabilize the AC voltage, and output the processed DC voltage to the energy storage device and the charging device through the DC bus respectively. Compared with the traditional technology, the intermediate inversion link is omitted, and the processed photovoltaic DC voltage is directly used for power supply or connected to the energy storage system, which reduces the cost required for using the photovoltaic power supply, and at the same time, reduces the energy loss caused by the conversion, and improves the overall efficiency.

[0061] In one embodiment, if Figure 2 As shown, the input components include:

[0062] A boost unit, one end of which is used to connect to the output end of the photovoltaic module;

[0063] A first switch tube, wherein the drain of the first switch tube is connected to the other end of the boost unit, and the source of the first switch tube is respectively connected to one end of the primary coil and the input end of the photovoltaic module;

[0064] The output diode D0 has an anode connected to the drain of the first switch tube and the other end of the boost unit, and a cathode connected to the other end of the primary coil.

[0065] The boost unit may be a Z-impedance network, and the multi-port converter may be an MPZSC (Multi-Port Z-Source Converter, an expandable multi-port Z-source converter).

[0066] Specifically, the boost unit is used to boost the received photovoltaic voltage. The specific boost size can be set according to the actual situation. It is not limited in the embodiment of the present application. The three-port converter is used as an example for explanation, that is, the number of input components is two, namely the first input component and the second input component. Figure 2 As shown, in order to distinguish the first input component from the second input component, the first switch tube in the first input component is marked as Sa1, and the first switch tube in the second input component is marked as Sb1, wherein the same-named end of the primary coil coupled to the output end of the first input component is the same as the same-named end of the secondary coil, and the same-named end of the primary coil coupled to the output end of the second input component is opposite to the same-named end of the secondary coil. In the first working mode, the first switch tube Sa1 in the first input component is controlled to be disconnected, and the first switch tube Sb1 in the second input component is controlled to be closed. In the second working mode, the first switch tube Sa1 in the first input component is controlled to be closed, and the first switch tube Sb1 in the second input component is disconnected, that is, the first switch tubes corresponding to the opposite and the same ends of the secondary coil are alternately connected, so that the transformer outputs AC voltage.

[0067] Exemplarily, the same-named end of the primary coil corresponding to the subsequently added input component can be the same as or opposite to the same-named end of the secondary coil, which is set according to actual conditions and will not be elaborated in the embodiments of the present application; if the same-named end of the primary coil corresponding to the subsequently added input component is the same as the same-named end of the secondary coil, then its working state is the same as that of the first input component, and so on.

[0068] In one embodiment, if Figure 2 As shown, the boost unit includes:

[0069] A first inductor, one end of which is connected to an output end of the photovoltaic module;

[0070] A first capacitor, one end of which is connected to the output end of the photovoltaic module;

[0071] A second capacitor, one end of the second capacitor is connected to the other end of the first inductor, and the other end of the second capacitor is respectively connected to the drain of the first switch tube and the anode of the output diode;

[0072] A second inductor, one end of the second inductor is connected to the other end of the first capacitor, and the other end of the second inductor is respectively connected to the drain of the first switch tube and the anode of the output diode;

[0073] A first diode, wherein an anode of the first diode is connected between the other end of the first inductor and one end of the second capacitor, and a cathode of the first diode is connected between the other end of the first capacitor and one end of the second inductor.

[0074] Specifically, a three-port converter is used as an example for explanation, that is, the number of input components is two, namely, a first input component and a second input component. Figure 2 As shown, in order to distinguish the first input component from the second input component, the components in the first input component are labeled as the first inductor La1, the first capacitor Ca1, the second capacitor Ca2, the second inductor La2 and the first diode Da1, and the components in the second input component are labeled as the first inductor Lb1, the first capacitor Cb1, the second capacitor Cb2, the second inductor Lb2 and the first diode Db1.

[0075] In one embodiment, if Figure 2 As shown, the output components include:

[0076] An output unit, wherein a first end of the output unit is connected to one end of the secondary coil, and a second end of the output unit is connected to the other end of the secondary coil;

[0077] A second switch tube S2, wherein a drain of the second switch tube S2 is connected to the first end of the output unit, and a source of the second switch tube S2 is connected to the DC bus;

[0078] A third switch tube S3, wherein the drain of the third switch tube S3 is connected to the second end of the output unit, and the source of the third switch tube S3 is respectively connected to the source of the second switch tube S2 and the DC bus;

[0079] a second diode D2, wherein an anode of the second diode D2 is connected to the third end of the output unit, and a cathode of the second diode D2 is connected to the DC bus;

[0080] The third diode D3 has an anode connected to the fourth end of the output unit, and a cathode connected to the cathode of the second diode D2 and the DC bus.

[0081] Specifically, by controlling the working states of the second switch tube S2 and the third switch tube S3 respectively, the output unit can output the DC voltage after rectification and voltage stabilization through the second diode D2 or the third diode D3 respectively, which can be connected to the energy storage system (energy storage battery) to ensure the bidirectional flow of energy and participate in maintaining the stability of the DC bus. On the other hand, it can be directly connected to the DC charging pile to charge the device.

[0082] It should be noted that the energy storage system can be charged (absorb energy) or discharged (release energy), so connecting the energy storage system to the DC bus can ensure the two-way flow of energy, that is, when the voltage on the DC bus is too low, the energy storage system can discharge to increase the voltage of the DC bus, and when the voltage on the DC bus is too high, the energy storage system can charge to reduce the voltage of the DC bus. Furthermore, the energy storage system can also provide reactive power and stabilize voltage fluctuations by adjusting the reactive power.

[0083] In one embodiment, if Figure 2 As shown, the second switch tube and the third switch tube are both N-type MOS tubes.

[0084] Wherein, the first switch tube in each input component is also an N-type MOS tube.

[0085] In one embodiment, if Figure 2 As shown, the output unit includes:

[0086] a fourth diode D4, wherein an anode of the fourth diode D4 is connected to the drain of the third switch tube S3, and a cathode of the fourth diode D4 is connected to the anode of the second diode D2;

[0087] a third capacitor C3, one end of the third capacitor C3 is connected to the cathode of the fourth diode D4 and the anode of the third diode D3, and the other end of the third capacitor C3 is connected to the drain of the second switch tube S2;

[0088] a fifth diode D5, wherein an anode of the fifth diode D5 is respectively connected to the other end of the third capacitor C3, one end of the secondary coil and the drain of the second switch tube S2, and a cathode of the fifth diode D5 is connected to the anode of the third diode D3;

[0089] The fourth capacitor C4, one end of the fourth capacitor C4 is respectively connected to the cathode of the fifth diode D5 and the anode of the third diode D3, and the other end of the fourth capacitor C4 is respectively connected to the anode of the fourth diode D4, the other end of the secondary coil and the drain of the third switch tube S3.

[0090] Specifically, the third capacitor C3 is charged from the secondary side of the transformer through the fourth diode D4, and the fourth capacitor C4 is charged from the secondary side of the transformer through the fifth diode D5.

[0091] It should be noted that the required DC voltage can be obtained by respectively setting the working parameters of the fourth diode D4, the third capacitor C3, the fifth diode D5 and the fourth capacitor C4, which will not be elaborated in the embodiment of the present application.

[0092] In one embodiment, the multi-port converter includes a first operating mode and a second operating mode in one switching cycle.

[0093] Specifically, a switching cycle of the multi-port converter can be set according to actual conditions, and is not limited in the embodiments of the present application. The first working mode and the second working mode last for equal periods of time, thereby forming a stable AC voltage on the secondary side of the transformer, so that the output component outputs the desired stable DC output voltage.

[0094] In one embodiment, when the multi-port converter is in the first working mode, the third switch tube is turned on.

[0095] Specifically, Figure 3 As shown, when the multi-port converter is in the first working mode, the photovoltaic voltage Vpv1 charges the first capacitor Ca1 and the second capacitor Ca2 of the first input component, and the first inductor La1 and the second inductor La2 of the first input component charge the first capacitor Ca1 and the second capacitor Ca2, the first switch tube Sa1 of the first input component is disconnected, and the primary voltage Vp1 of the transformer is equal to the input voltage (Vpv1) plus the sum of the voltage between the first inductor La1 and the second inductor La2; the first switch tube Sb1 of the second input component is turned on, so the output diode D0 in the second input component is short-circuited, and the primary voltage Vp2 of the transformer is 0, and at this time the fourth capacitor C4 is charged from the secondary side of the transformer through the fifth diode D5.

[0096] For example, Figure 3 The dashed arrow in the figure indicates the direction of current.

[0097] It should be noted that the voltage in the boost unit is as follows:

[0098] Vca1 = VLa1 = Vca2 = VLa2

[0099]

[0100] Among them, Vca1 represents the voltage flowing through the first capacitor Ca1; Vca2 represents the voltage flowing through the second capacitor Ca2; VLa1 represents the voltage flowing through the first inductor La1; VLa2 represents the voltage flowing through the second inductor La2; Dsa1 represents the duty cycle of the first switching tube in the first input component; Vpv1 represents the photovoltaic voltage corresponding to the first input component.

[0101] The inductor voltage can be expressed as:

[0102] VLb1 = Vcb2 + Vpv2

[0103] VLb2 = Vcb1 + Vpv2

[0104] The voltage across the transformer can be expressed as:

[0105] Vp1 = Vpv1 + VLa1 + VLa2

[0106] Vsec = (Vpv1 + VLa1 + VLa2) n = n Vp1

[0107] Among them, Vcb1 represents the voltage flowing through the first capacitor Cb1; Vcb2 represents the voltage flowing through the second capacitor Cb2; VLb1 represents the voltage flowing through the first inductor Lb1; VLb2 represents the voltage flowing through the second inductor Lb2; Vpv1 represents the photovoltaic voltage corresponding to the first input component; Vpv2 represents the photovoltaic voltage corresponding to the second input component; Vp1 represents the primary voltage of the transformer corresponding to the first input component; Vsec represents the secondary voltage of the transformer; n represents the transformation ratio between the primary and secondary sides of the transformer.

[0108] In one embodiment, when the multi-port converter is in the second working mode, the second switch tube is turned on.

[0109] Specifically, Figure 4 As shown, when the multi-port converter is in the second working mode, the photovoltaic voltage Vpv2 charges the first capacitor Cb1 and the second capacitor Cb2 of the second input component, and the first inductor Lb1 and the second inductor Lb2 of the second input component charge the first capacitor Cb1 and the second capacitor Cb2, the first switch tube Sb1 of the second input component is disconnected, and the primary voltage Vp2 of the transformer is equal to the input voltage (Vpv2) plus the sum of the voltage between the first inductor Lb1 and the second inductor Lb2; the first switch tube Sa1 of the first input component is turned on, so the output diode D0 in the first input component is short-circuited, and the primary voltage Vp1 of the transformer is 0, and at this time the third capacitor C3 is charged from the secondary side of the transformer through the fourth diode D4.

[0110] For example, Figure 4 The dashed arrow in the figure indicates the direction of current.

[0111] It should be noted that the voltage in the boost unit is as follows:

[0112] Vcb1 = VLb1 = Vcb2 = VLb2

[0113]

[0114] Among them, Vcb1 represents the voltage flowing through the first capacitor Cb1; Vcb2 represents the voltage flowing through the second capacitor Cb2; VLb1 represents the voltage flowing through the first inductor Lb1; VLb2 represents the voltage flowing through the second inductor Lb2; Dsb1 represents the duty cycle of the first switch tube in the second input component; Vpv2 represents the photovoltaic voltage corresponding to the second input component.

[0115] The inductor voltage can be expressed as:

[0116] VLa1 = Vca2 + Vpv1

[0117] VLa2 = Vca1 + Vpv1

[0118] The voltage across the transformer can be expressed as:

[0119] Vp2 = Vpv1 + VLb1 + VLb2

[0120] Vsec = (Vpv2 + VLb1 + VLb2) n = n Vp2

[0121] Among them, Vca1 represents the voltage flowing through the first capacitor Ca1; Vca2 represents the voltage flowing through the second capacitor Ca2; VLa1 represents the voltage flowing through the first inductor La1; VLa2 represents the voltage flowing through the second inductor La2; Vpv1 represents the photovoltaic voltage corresponding to the first input component; Vpv2 represents the photovoltaic voltage corresponding to the second input component; Vp2 represents the primary voltage of the transformer corresponding to the second input component; Vsec represents the secondary voltage of the transformer; n represents the transformation ratio between the primary and secondary sides of the transformer.

[0122] Due to the different ends of the transformer primary coil corresponding to each input component, AC is formed on the secondary side of the transformer. By repeating the above process, a stable AC voltage can be formed on the secondary side of the transformer. The third switch tube is controlled to be turned on in the first working mode, and the second switch tube is controlled to be turned on in the second working mode, so as to obtain the desired stable DC output voltage. On the one hand, it can be connected to the energy storage system to ensure the bidirectional flow of energy and participate in maintaining the stability of the DC bus. On the other hand, it can be directly connected to the charging pile to charge the equipment.

[0123] In an exemplary embodiment, a charging system is provided, comprising a control module, a driving module connected to the control module, and a multi-port converter as described above connected to the driving module; wherein:

[0124] The driving module is respectively connected to the gate of the first switch tube, the gate of the second switch tube and the gate of the third switch tube, and the control module is used to connect the energy storage device, the photovoltaic component and the charging device.

[0125] Specifically, the control module can divide the charging system into the following three working modes according to the load of the charging pile, the photovoltaic output and the energy storage status. When the number of charging piles is low, the output of the photovoltaic system and the energy storage system can meet the charging demand; if the number of charging piles is large, the number of system ports (the number of input components) can be expanded to increase the energy provided by the photovoltaic system. PV (power generated by photovoltaic system), P BAT (power absorbed by energy storage system); P EV (power required by electric vehicles), and compare the three to determine the working mode of the charging system, such as Figure 5 As shown:

[0126] When the charging system is in working mode 1, the photovoltaic system generates enough power to charge the car, and the excess energy is stored in the energy storage system. At this time, the system power expression is:

[0127] P PV ≥ P BAT + P EV ;

[0128] When the charging system is in working mode 2, the photovoltaic system generates more power than the car charging power, and the energy storage can charge the car. At this time, the power expression is:

[0129] P BAT ≥ P EV ;

[0130] When the charging system is in working mode 3, if the photovoltaic system outputs insufficient power, the energy storage system can supplement the insufficient power. At this time, the power expression is:

[0131] P PV + P BAT ≥ P EV ;

[0132] If the photovoltaic system generates insufficient power and the energy storage system cannot supplement the insufficient power, the number of photovoltaic power sources (the number of input components) can be expanded according to the load needs to increase the energy provided by the photovoltaic system. When the port expansion is completed, the P PV , P BAT and P EV , re-determine the system's working mode.

[0133] The charging system generally switches between the above three modes when in operation. In order to avoid damage to the energy storage system battery, when the energy storage battery SOC (State of Charge) is lower than 20%, the control module outputs the first alarm signal, and the energy storage SOC enters the discharge warning; when the SOC is higher than 80%, the control module outputs the second alarm signal, and the energy storage SOC enters the charging warning. The division of the charging system working modes is shown in Table 1.

[0134] Table 1

[0135]

[0136] The control module performs regular maintenance and inspection on the charging equipment according to the working mode of the charging system to effectively ensure the normal operation of the equipment.

[0137] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0138] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0139] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A multi-port converter, characterized in that: include: A transformer, comprising a secondary coil and at least two primary coils; At least two input components, the input end of the input component is used to connect to the photovoltaic component, the output end of the input component is coupled to the primary coil, and the input component is used to boost the photovoltaic voltage received from the photovoltaic component output; wherein the same-named end of the primary coil coupled to the output end of any one of the input components is opposite to the same-named end of the primary coil coupled to the output end of another one of the input components, the same-named end of the primary coil coupled to the output end of any one of the input components is the same as the same-named end of the secondary coil, and the same-named end of the primary coil coupled to the output end of another one of the input components is opposite to the same-named end of the secondary coil; An output component, wherein the input end of the output component is coupled to the secondary coil, and the output end of the output component is respectively connected to the energy storage device and the charging device through a DC bus. The output component is used to receive the AC voltage output by the transformer, rectify and stabilize the AC voltage, and output the processed DC voltage to the energy storage device and the charging device through the DC bus.

2. The multi-port converter according to claim 1, characterized in that: The input component comprises: A boost unit, one end of which is used to connect to the output end of the photovoltaic module; a first switch tube, wherein the drain of the first switch tube is connected to the other end of the boost unit, and the source of the first switch tube is respectively connected to one end of the primary coil and the input end of the photovoltaic module; An output diode, wherein the anode of the output diode is respectively connected to the drain of the first switch tube and the other end of the boost unit, and the cathode of the output diode is connected to the other end of the primary coil.

3. The multi-port converter according to claim 2, characterized in that: The boost unit comprises: A first inductor, one end of which is connected to an output end of the photovoltaic module; A first capacitor, one end of which is connected to the output end of the photovoltaic module; a second capacitor, one end of the second capacitor being connected to the other end of the first inductor, and the other end of the second capacitor being connected to the drain of the first switch tube and the anode of the output diode respectively; a second inductor, one end of which is connected to the other end of the first capacitor, and the other end of which is respectively connected to the drain of the first switch tube and the anode of the output diode; A first diode, wherein an anode of the first diode is connected between the other end of the first inductor and one end of the second capacitor, and a cathode of the first diode is connected between the other end of the first capacitor and one end of the second inductor.

4. The multi-port converter according to claim 1, characterized in that: The output component comprises: an output unit, wherein a first end of the output unit is connected to one end of the secondary coil, and a second end of the output unit is connected to the other end of the secondary coil; a second switch tube, wherein a drain of the second switch tube is connected to the first end of the output unit, and a source of the second switch tube is connected to the DC bus; a third switch tube, wherein a drain of the third switch tube is connected to the second end of the output unit, and a source of the third switch tube is respectively connected to the source of the second switch tube and the DC bus; a second diode, wherein an anode of the second diode is connected to the third end of the output unit, and a cathode of the second diode is connected to the DC bus; A third diode, wherein an anode of the third diode is connected to the fourth end of the output unit, and a cathode of the third diode is connected to the cathode of the second diode and the DC bus respectively.

5. The multi-port converter according to claim 4, characterized in that: The second switch tube and the third switch tube are both N-type MOS tubes.

6. The multi-port converter according to claim 4, characterized in that: The output unit comprises: a fourth diode, wherein an anode of the fourth diode is connected to the drain of the third switch tube, and a cathode of the fourth diode is connected to the anode of the second diode; a third capacitor, one end of which is connected to the cathode of the fourth diode and the anode of the third diode respectively, and the other end of which is connected to the drain of the second switch tube; a fifth diode, wherein an anode of the fifth diode is respectively connected to the other end of the third capacitor, one end of the secondary coil and the drain of the second switch tube, and a cathode of the fifth diode is connected to the anode of the third diode; A fourth capacitor, one end of which is respectively connected to the cathode of the fifth diode and the anode of the third diode, and the other end of which is respectively connected to the anode of the fourth diode, the other end of the secondary coil and the drain of the third switch tube.

7. The multi-port converter according to claim 6, characterized in that: The multi-port converter includes a first working mode and a second working mode in one switching cycle.

8. The multi-port converter according to claim 7, characterized in that: When the multi-port converter is in the first working mode, the third switch tube is turned on.

9. The multi-port converter according to claim 7, characterized in that: When the multi-port converter is in the second working mode, the second switch tube is turned on.

10. A charging system, characterized in that: The invention comprises a control module, a driving module connected to the control module, and a multi-port converter according to any one of claims 1 to 9 connected to the driving module; wherein: The driving module is respectively connected to the gate of the first switch tube, the gate of the second switch tube and the gate of the third switch tube, and the control module is used to connect the energy storage device, the photovoltaic component and the charging device.

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