Photovoltaic power generation and V2H cooperative control system based on multi-mode switching and control method thereof

Abstract

The invention discloses a photovoltaic power generation and V2H cooperative control system based on multi-mode switching and a control method thereof. The control system comprises a V2H system, a photovoltaic system and a converter module. The method comprises the steps that real-time data, prediction data and electric vehicle data of the photovoltaic power generation and V2H cooperative control system based on multi-mode switching are acquired; determining a working mode of the photovoltaic power generation and V2H cooperative control system based on multi-mode switching and a cooperative control strategy matched with the working mode according to the prediction data, the real-time data and the electric vehicle data; and controlling the photovoltaic power generation and V2H cooperative control system based on multi-mode switching according to the confirmed working mode and the cooperative control strategy matched with the working mode so as to balance the household load demand and the electric quantity demand of an electric vehicle battery. The utilization rate of the photovoltaic system and the stability of household load power supply can be improved.

Description

Technical Field

[0001] The present invention relates to the field of new energy, and particularly to a photovoltaic power generation and V2H collaborative control system based on multi-mode switching and its control method. Background Art

[0002] With the rapid development of distributed new energy, more and more users choose to install photovoltaic panels on the roofs of their homes. While realizing self-use of electricity, they can also feed the surplus electricity back to the grid. However, the uncertainty of photovoltaic power generation leads to low utilization efficiency and brings new hidden dangers to household electricity. Especially in the event of a sudden power outage, a stable and reliable power supply cannot be provided. Summary of the Invention

[0003] The present invention provides a photovoltaic power generation and V2H collaborative control system based on multi-mode switching and its control method, aiming to solve the problems of low energy utilization efficiency and unstable power supply in existing household systems.

[0004] In a first aspect, the present invention provides a photovoltaic power generation and V2H collaborative control system based on multi-mode switching, which includes a V2H system, a photovoltaic system, and an inverter module; the V2H system is connected to a DC bus; the photovoltaic system is connected to the DC bus; the DC side of the inverter is connected to the DC bus, and the AC side of the inverter is respectively connected to the power grid and a household load.

[0005] Further, the V2H system includes an electric vehicle battery and a bidirectional voltage conversion circuit; the electric vehicle battery is connected to the bidirectional voltage conversion circuit, and the bidirectional voltage conversion circuit is connected to the DC bus.

[0006] Further, the photovoltaic system includes photovoltaic panels and a boost circuit; the photovoltaic panels are connected to the boost circuit, and the boost circuit is connected to the DC bus.

[0007] Further, the inverter module includes a grid-connected three-level inverter circuit and an off-grid three-level inverter circuit; the DC sides of both the grid-connected three-level inverter circuit and the off-grid three-level inverter circuit are connected to the DC bus, the AC side of the grid-connected three-level inverter circuit is connected to the power grid, and the AC side of the off-grid three-level inverter circuit is connected to the household load.

[0008] In a second aspect, the present invention further provides a control method, which is used to control the photovoltaic power generation and V2H collaborative control system based on multi-mode switching according to any one of the above, and the method includes: Obtain the real-time data, prediction data, and electric vehicle data of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching, where the real-time data includes the real-time power of household photovoltaic power generation and the real-time power of household loads, the prediction data includes the predicted household photovoltaic power generation power and the predicted household load power, and the electric vehicle data includes the electric vehicle battery power and the allowable discharge power of the electric vehicle; Confirm the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching and the collaborative control strategy matching the working mode according to the prediction data, the real-time data, and the electric vehicle data; Control the photovoltaic power generation and V2H collaborative control system based on multi-mode switching according to the confirmed working mode and the collaborative control strategy matching the working mode to balance the household load demand and the electric vehicle battery power demand.

[0009] The present invention discloses a photovoltaic power generation and V2H collaborative control system based on multi-mode switching and its control method. The photovoltaic power generation and V2H collaborative control system based on multi-mode switching includes a V2H system, a photovoltaic system, and an inverter module. Both the V2H system and the photovoltaic system are connected to the DC bus, and the inverter module is respectively connected to the DC bus, the power grid, and the household loads. The working mode of the control system and the control strategy matching the working mode can be confirmed according to the real-time data, the prediction data, and the electric vehicle data. Thus, different control strategies can be adopted for different working modes to balance the household load demand and the electric vehicle battery power demand, and further improve the utilization rate of the photovoltaic system and the stability of household power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0011] Figure 1 is a block diagram of a photovoltaic power generation and V2H collaborative control system based on multi-mode switching provided by an embodiment of the present invention; Figure 2 is an energy system diagram of a photovoltaic power generation and V2H collaborative control system provided by an embodiment of the present invention; Figure 3 is a flowchart of a control method provided by an embodiment of the present invention; Figure 4 is a topology diagram of a bidirectional voltage conversion circuit provided by an embodiment of the present invention; Figure 5It is the topology diagram of the boost circuit provided by an embodiment of the present invention; Figure 6 It is the topology diagram of the grid-connected three-level converter circuit provided by an embodiment of the present invention; Figure 7 It is the topology diagram of the off-grid three-level converter circuit provided by an embodiment of the present invention; Figure 8 It is the current inner-loop control block diagram of the V2H system provided by an embodiment of the present invention; Figure 9 It is the voltage outer-loop control block diagram of the V2H system provided by an embodiment of the present invention; Figure 10 It is the positive and negative sequence separation control block diagram based on the delay cancellation technology provided by an embodiment of the present invention; Figure 11 It is the constant current mode control block diagram provided by an embodiment of the present invention; Figure 12 It is the control flow chart of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching provided by an embodiment of the present invention; Figure 13 It is the schematic diagram of the power curve of the photovoltaic power generation and V2H collaborative system of a certain household within a day provided by an embodiment of the present invention; Figure 14 It is the waveform diagram of the three-phase voltage and current on the AC side of the rectifier mode converter provided by an embodiment of the present invention; Figure 15 It is the waveform diagram of the voltage and current of phase A on the AC side of the rectifier mode converter provided by an embodiment of the present invention; Figure 16 It is the waveform diagram of the three-phase voltage and current on the AC side of the converter under the rectifier mode switching to the inverter mode provided by an embodiment of the present invention; Figure 17 It is the waveform diagram of the voltage and current of phase A on the AC side of the converter under the rectifier mode switching to the inverter mode provided by an embodiment of the present invention; Figure 18 It is the waveform diagram of the three-phase voltage and current on the AC side of the converter with an asymmetric load under the improved positive and negative zero sequence separation control provided by an embodiment of the present invention; Figure 19 It is the waveform diagram of the three-phase voltage and current on the AC side of the converter under the grid-connected mode switching to the off-grid mode provided by an embodiment of the present invention; Figure 20 It is the waveform diagram of the three-phase voltage and current on the AC side of the converter under the inverter mode switching to the rectifier mode provided by an embodiment of the present invention; Figure 21 It is the waveform diagram of the voltage and current of phase A on the AC side of the converter under the inverter mode switching to the rectifier mode provided by an embodiment of the present invention. Detailed implementation manners

[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0013] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, wholes, operations, elements, components and / or their combinations.

[0014] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in this specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms. It should be further understood that the term "and / or" used in this specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0015] In addition, the directional terms mentioned in the present invention, such as "up", "down", "front", "back", "left", "right", "inside", "outside", "side", etc., are only references to the directions in the attached drawings and the usage state of the product. Therefore, the directional terms used are for explaining and understanding the present invention, rather than for limiting the present invention. In addition, in the drawings, structures that are similar or the same are denoted by the same reference numerals.

[0016] See Figure 1 , the present invention provides a photovoltaic power generation and V2H collaborative control system 100 based on multi-mode switching, which includes a V2H system 10, a photovoltaic system 20, and an inverter module 30; the V2H system 10 is connected to the DC bus; the photovoltaic system 20 is connected to the DC bus; the DC side of the inverter is connected to the DC bus, and the AC side of the inverter is respectively connected to the power grid 200 and the household load 300.

[0017] Specifically, the photovoltaic power generation and V2H collaborative control system 100 based on multi-mode switching (hereinafter referred to as the control system) may include a V2H system 10, a photovoltaic system 20, and an inverter module 30. The V2H system 10 (Vehicle-to-Home) is a kind of energy storage system that can use the electric vehicle battery 11 as home energy. That is, when the electric vehicle is idle, the electric vehicle battery 11 can supply power to the home load 300. The photovoltaic system 20 may include photovoltaic panels 21 for supplying power to the home load 300, and the inverter module 30 is used to connect the DC bus with the power grid 200 and the home load 300.

[0018] The V2H system 10, the photovoltaic system 20, and the inverter module 30 are all connected to the DC bus. The photovoltaic system 20 is used to transmit the generated power to the DC bus side. The V2H system 10 is used to realize the bidirectional energy flow between the DC bus and the electric vehicle. The inverter module 30 is used to connect the V2H system 10 and the photovoltaic system 20 with the power grid 200 and the home load 300 through the DC bus.

[0019] In use, the working mode of the control subsystem can be adjusted according to real-time data, predicted data, and electric vehicle data to balance the demands between the home load 300 and the electric vehicle battery 11. Among them, the real-time data includes the real-time power of home photovoltaic power generation and the real-time power of the home load. The predicted data includes the predicted power of home photovoltaic power generation and the predicted power of the home load. The electric vehicle data includes the electric vehicle battery power and the allowable discharge power of the electric vehicle. For example, the working mode can include a fixed working mode and an adaptive intelligent control mode. The fixed working mode can be adjusted according to real-time data. When the real-time power of home photovoltaic power generation is greater than the real-time power of the home load 300 and the electric vehicle battery 11 of the V2H system 10 is not fully charged, after the power generation of the photovoltaic system 20 meets the demand of the home load 300, it preferentially supplies power to the electric vehicle battery 11 for charging. If the electric vehicle battery 11 is fully charged, after the power generation of the photovoltaic system 20 meets the demand of the home load 300, it preferentially supplies power to the power grid 200. If the real-time power of home photovoltaic power generation is less than or equal to the real-time power of the home load 300 and the electric vehicle battery 11 power is greater than the allowable discharge power of the electric vehicle, it can be decided according to the electricity price whether to supply power to the home load 300 by the power grid 200 or by the electric vehicle battery 11, or both supply power to the home load 300 at the same time. If the electric vehicle battery 11 power is less than or equal to the allowable discharge power of the electric vehicle, the power grid 200 and the photovoltaic system 20 charge the electric vehicle battery 11 at the same time. If a power outage fault occurs and the real-time power of home photovoltaic power generation is less than or equal to the real-time power of the home load 300, the electric vehicle battery 11 preferentially supplies power to the home load 300.

[0020] For the adaptive intelligent control mode, the power supply can be automatically adjusted according to the user's driving habits, electricity consumption habits, and photovoltaic power generation data. For example, during the low electricity consumption period, if the electric vehicle is not fully charged, the power generated by the photovoltaic system 20 can be preferentially supplied to the electric vehicle battery 11. During the high electricity consumption period, if the user has no driving demand in the future, the power of the electric vehicle battery 11 and the power generated by the photovoltaic system 20 can be preferentially supplied to the household load 300.

[0021] As a further embodiment, the V2H system 10 includes an electric vehicle battery 11 and a bidirectional voltage conversion circuit 12; the electric vehicle battery 11 is connected to the bidirectional voltage conversion circuit 12, and the bidirectional voltage conversion circuit 12 is connected to the DC bus.

[0022] Among them, the V2H system 10 may include an electric vehicle battery 11 and a bidirectional voltage conversion circuit 12. As Figure 2 shown, the bidirectional voltage conversion circuit 12 may be a bidirectional Buck / boost circuit. The electric vehicle battery 11 can be connected to the DC bus through the bidirectional voltage conversion circuit 12, and thus can supply power to the household load 300. At the same time, the photovoltaic system 20 can also charge the electric vehicle battery 11 through the bidirectional voltage conversion circuit 12. As Figure 4 shown, Figure 4 is the topology diagram of the bidirectional voltage conversion circuit 12, and this circuit can realize the bidirectional flow of energy from the electric vehicle battery 11 side to the DC bus side.

[0023] As a further embodiment, the photovoltaic system 20 includes a photovoltaic panel 21 and a boost circuit 22; the photovoltaic panel 21 is connected to the boost circuit 22, and the boost circuit 22 is connected to the DC bus.

[0024] Among them, the photovoltaic system 20 may include a photovoltaic panel 21 and a boost circuit 22. As Figure 2 shown, the boost circuit 22 may be a Boost circuit. The photovoltaic panel 21 is connected to the DC bus through the boost circuit 22, and can supply power to the electric vehicle battery 11, the household load 300, or the power grid 200 through the boost circuit 22. As Figure 5 shown, Figure 5 is the topology diagram of the boost circuit 22, and this circuit can realize the flow of the photovoltaic power generation power of the photovoltaic system 20 from the photovoltaic panel 21 side to the DC bus side.

[0025] As a further embodiment, the converter module 30 includes a grid-connected three-level converter circuit 31 and an off-grid three-level converter circuit 32; the DC sides of the grid-connected three-level converter circuit 31 and the off-grid three-level converter circuit 32 are both connected to the DC bus, the AC side of the grid-connected three-level converter circuit 31 is connected to the power grid 200, and the AC side of the off-grid three-level converter circuit 32 is connected to the household load 300.

[0026] Among them, the converter module 30 may include a grid-connected three-level converter circuit 31 and an off-grid three-level converter circuit 32. As Figure 2 shown, both the grid-connected three-level converter circuit 31 and the off-grid three-level converter circuit 32 may be T-type three-level converter circuits. The photovoltaic system 20 can be connected to the power grid 200 through the grid-connected three-level converter circuit 31, so as to realize power supply to the power grid 200. The photovoltaic system 20 and the V2H system 10 can also be connected to the household load 300 through the off-grid three-level AC circuit, which is convenient for supplying power to the household load 300. Please refer to Figure 6 and Figure 7 , Figure 6 is the topology diagram of the grid-connected three-level converter circuit 31, Figure 7 is the topology diagram of the off-grid three-level converter circuit 32, Figure 6 and Figure 7 The provided topology diagrams can realize the conversion from DC to AC, mainly control the grid feeding power and the voltage supplied to the household load 300, and can realize the grid feeding function and the power supply function for the household load 300. Both three-level converters can be used as backup lines. When the converter of another system fails, it can be switched to another system to replace the faulty converter at any time.

[0027] Please refer to Figure 3 , the present invention also provides a control method, which is used to control the photovoltaic power generation and V2H collaborative control system based on multi-mode switching described in any one of the above embodiments. The method includes steps S110 - S130.

[0028] S110, obtain the real-time data, prediction data and electric vehicle data of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching. Among them, the real-time data includes the real-time power of household photovoltaic power generation and the real-time power of household load, the prediction data includes the predicted household photovoltaic power and the predicted household load power, and the electric vehicle data includes the electric vehicle battery power and the allowable discharge power of the electric vehicle.

[0029] In the embodiments of the present invention, the real-time data may include the real-time power of household photovoltaic power generation and the real-time power of household loads. The real-time power of household photovoltaic power generation is the real-time power generation of the photovoltaic system, and the real-time power of household loads is the total power required by household loads in real time. The predicted data may include the predicted power of household photovoltaic power generation and the predicted power of household loads. The predicted power of household photovoltaic power generation refers to the power generation of the photovoltaic system through weather data over a period of time in the future. For example, the power generation of the photovoltaic system in the next 24 hours is predicted through weather data within 24 hours. The predicted power of household loads may refer to the situation of household loads within the next 24 hours, which can be specifically predicted based on the historical data of household loads. The prediction accuracy can be improved through neural network algorithms during prediction. The electric vehicle data may include the battery power of the electric vehicle and the allowable discharge power of the electric vehicle. The battery power of the electric vehicle is the remaining power of the electric vehicle battery currently, and the allowable discharge power of the electric vehicle is the maximum discharge amount allowed by the electric vehicle battery. The control system can obtain the predicted power of household photovoltaic power generation and the predicted power of household loads, and collect in real time the real-time power of household photovoltaic power generation, the real-time power of household loads, the battery power of the electric vehicle, and the allowable discharge power of the electric vehicle, so as to confirm the working mode.

[0030] S120. Confirm the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching and the collaborative control strategy matching the working mode according to the predicted data, the real-time data, and the electric vehicle data.

[0031] In the embodiments of the present invention, the control system may preset multiple working modes, and each working mode corresponds to a different collaborative control strategy. The specific working mode can be confirmed through the predicted data, the real-time data, and the electric vehicle data, and then the corresponding collaborative control strategy can be confirmed.

[0032] S130. Control the photovoltaic power generation and V2H collaborative control system based on multi-mode switching according to the confirmed working mode and the collaborative control strategy matching the working mode to balance the household load demand and the electric vehicle battery power demand.

[0033] In the embodiments of the present invention, after the working mode is confirmed, the corresponding collaborative control strategy can be confirmed, and the V2H system, the photovoltaic system, and the converter module of the control system can be controlled based on the collaborative control strategy to balance the household load demand and the electric vehicle battery power demand.

[0034] Such as Figure 12As shown, the control system can confirm whether to adopt a fixed working mode or an adaptive intelligent regulation mode based on the predicted data and real-time data, and adopt different specific control methods according to different working modes. In the adaptive intelligent regulation mode, the energy can be redistributed according to the historical power data, real-time data, predicted data and the charging habits of the user's electric vehicle, that is, the electric energy can be intelligently allocated. In the fixed working mode, the static constraint conditions can be judged according to the real-time data and the allowable discharge threshold of the electric vehicle, so as to confirm the specific working mode.

[0035] In one embodiment, for example, in the embodiment of the present invention, the working modes include a fixed working mode and an adaptive intelligent regulation mode, and the method further includes the following steps: Confirm the difference between the predicted data and the real-time data; If the difference between the predicted data and the real-time data is greater than a first preset threshold, switch the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching to the fixed working mode; If the difference between the predicted data and the real-time data is less than or equal to the first preset threshold, switch the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching to the adaptive intelligent regulation mode.

[0036] In the embodiment of the present invention, the predicted data includes the predicted photovoltaic power generation power and the predicted household load power, and the real-time data may include the real-time photovoltaic power generation power of the household and the real-time household load power. When the difference between the predicted data and the real-time data is large, the working mode can be switched to the fixed working mode. When the difference between the predicted data and the real-time data is small, the working mode can be switched to the adaptive intelligent regulation mode. That is, when the difference between the predicted data and the real-time data is greater than the first preset threshold, the working mode is switched to the fixed working mode. When the difference between the predicted data and the real-time data is less than or equal to the first preset threshold, the working mode is switched to the adaptive intelligent regulation mode. Among them, the first preset threshold is an empirical value, which can be set according to different household environments.

[0037] For example, if the first preset threshold is C, the predicted photovoltaic power generation at a certain moment can be predicted as A1 based on weather data. At this moment, the real-time household photovoltaic power is B1. If the absolute value of the difference between A1 and B1 is D1 and D1 is greater than C, the working mode can be switched to the fixed working mode. Or if the predicted household load power is A2, the real-time household load power is B2, the absolute value of the difference between A2 and B2 is D2, and D2 is greater than C, the working mode can be switched to the fixed working mode. To more accurately confirm the working mode, the magnitudes between the predicted photovoltaic power generation and the real-time household photovoltaic power and between the predicted household load power and the real-time household load power can be further confirmed. For example, when the predicted photovoltaic power generation is greater than the real-time household photovoltaic power and the predicted household load power is greater than the real-time household load power, the working mode can be switched to the adaptive intelligent control mode. When the predicted photovoltaic power generation is less than or equal to the real-time household photovoltaic power or the predicted household load power is less than or equal to the real-time household load power, the working mode is switched to the fixed working mode.

[0038] In the fixed working mode, the control system can balance the electric vehicle battery demand and the household load demand according to the real-time data and the electric vehicle data. In the adaptive intelligent control mode, the control system can balance the electric vehicle battery demand and the household load demand according to the predicted data, driving habits, historical data, real-time data, and electric vehicle data.

[0039] In one embodiment, for example, in the embodiment of the present invention, the fixed working mode includes a photovoltaic priority charging mode, a photovoltaic surplus power grid connection mode, a photovoltaic and V2H collaborative power supply mode, a power grid and photovoltaic collaborative charging mode, and an electric vehicle emergency power supply mode. The method further includes the following steps: If the real-time household photovoltaic power is greater than the real-time household load power and the electric vehicle battery is not fully charged, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the photovoltaic priority charging mode; If the working mode is the photovoltaic priority charging mode, control the V2H system, the photovoltaic system, and the converter module to all adopt a double closed-loop control strategy, and control the converter module to be in the off-grid mode; If the real-time household photovoltaic power is greater than the real-time household load power and the electric vehicle battery is fully charged, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the photovoltaic surplus power grid connection mode; If the working mode is the PV surplus power grid connection mode, then control the V2H system not to work, control the PV system to adopt a double closed-loop control strategy, and control the converter module to adopt a single closed-loop control and be in the grid connection mode; If the real-time power of the household PV power generation is less than or equal to the real-time power of the household load, and the battery power of the electric vehicle is greater than the allowable discharge power of the electric vehicle, then switch the working mode of the PV power generation and V2H collaborative control system based on multi-mode switching to the PV and V2H collaborative power supply mode; If the working mode is the PV and V2H collaborative power supply mode, then control both the V2H system and the PV system to adopt a double closed-loop control strategy, and control the converter module to adopt a double closed-loop control and be in the off-grid mode; If the real-time power of the household PV power generation is less than or equal to the real-time power of the household load, and the battery power of the electric vehicle is less than or equal to the allowable discharge power of the electric vehicle, then switch the working mode of the PV power generation and V2H collaborative control system based on multi-mode switching to the grid and PV collaborative charging mode; If the working mode is the grid and PV collaborative charging mode, then control the V2H system not to work, control the PV system to adopt a double closed-loop control strategy, and control the converter module to adopt a double closed-loop control and be in the off-grid mode; If a power outage fault is detected and the real-time power of the household PV power generation is less than or equal to the real-time power of the household load, then switch the working mode of the PV power generation and V2H collaborative control system based on multi-mode switching to the electric vehicle emergency power supply mode; If the working mode is the electric vehicle emergency power supply mode, then control both the V2H system and the PV system to adopt a double closed-loop control strategy, and control the converter module to adopt a double closed-loop control and be in the off-grid mode.

[0040] The following will respectively elaborate in detail on how to confirm the five specific modes in the fixed working mode and the collaborative control strategies in different working modes.

[0041] I. PV Priority Charging Mode In the PV priority charging mode, there are: P load ≤P PV (1); SOC ev <100% (2); Among them, P PV is the real-time power of the household PV power generation, P load is the real-time power of the household load, and SOC ev is the battery power of the electric vehicle and other data. For example, if Pload = 3 kW, P PV = 4 kW, SOC ev = 80%, SOC limit = 50%, SOC limit is the allowable discharge power of the electric vehicle. At this time, the control system operates in the photovoltaic priority charging mode. The residential photovoltaic power generation is higher than the household consumption demand, and the electric vehicle battery is not fully charged. The excess power will be used to charge the electric vehicle. The bidirectional Buck / boost circuit on the electric vehicle battery side uses a voltage-current double closed-loop control strategy. The main control objective is to stabilize the DC bus voltage. The power P on the electric vehicle side ev = P load - P PV , at this time P ev is less than zero, and the power flows from the DC bus side to the electric vehicle battery to charge the battery. The current inner loop control block diagram of the bidirectional voltage conversion circuit on the electric vehicle battery side is as shown in Figure 8 shown, and the voltage outer loop control block diagram is as shown in Figure 9 shown.

[0042] The boost circuit on the photovoltaic panel side uses a voltage-current double closed-loop control strategy to achieve maximum power point tracking control. Its double closed-loop control strategy is similar to the Boost boost mode of the bidirectional voltage conversion circuit. Its current inner loop control strategy is the same, and the voltage outer loop control objective is changed to the voltage on the photovoltaic panel side to achieve MPPT control.

[0043] The T-type three-level converter is operating in the off-grid mode at this time. The grid-side relay is disconnected, and the household load-side relay is closed. Since a three-phase four-wire T-type three-level converter is used and there is a load imbalance, it is necessary to separate the positive-sequence component, negative-sequence component, and zero-sequence component from the inverter voltage and control them separately. Its main control objective is to ensure the stability of the AC voltage on the load side under the condition of unbalanced three-phase loads. When controlling the voltage on the inverter side, the d-axis voltage component in its dq rotating coordinate system is affected by the coupling of the q-axis voltage component, and the current component is the same. Therefore, the dq-axis voltage and current are coupled with each other in the mathematical model. If they are not separated, the control requirements cannot be achieved. In order to achieve the independent closed-loop control of the dq-axis components, the decoupling control of the AC current loop is realized by the method of feed-forward grid voltage compensation, and the decoupling control of the AC voltage loop is realized by feed-forward load current compensation. For the T-type three-level converter in the off-grid mode, when the output terminal is connected to an asymmetric three-phase load, it will cause distortion of the output three-phase voltage. In order to ensure the stable operation of the load, the symmetry of the output three-phase voltage must be maintained. Therefore, in order to ensure the three-phase symmetry of the output signal, that is, the output signal only contains the positive-sequence component, the traditional closed-loop control method cannot be used. Instead, the sequence components of the output signal should be separated first, and then each component should be adjusted separately. For the positive and negative sequence components, the Delay Signal Cancellation (DSC) technology is used to separate the positive and negative sequences of the output three-phase voltage and current. By performing PI control on the separated positive and negative sequence components, the negative sequence component is ensured to be 0. The positive and negative sequence control block diagrams are as shown in Figure 8 shown. For the zero-sequence component, virtual orthogonality construction is required to convert it into a DC quantity. Then, like the positive and negative sequence components, the zero-sequence component can achieve static error-free control through a PI controller. This technology can be understood by ordinary personnel in this professional field. The control strategy of the zero-sequence component converted into a DC quantity is the same as that of the positive and negative sequence components, and no further explanation will be given here.

[0044] II. Photovoltaic surplus power grid connection mode In the photovoltaic surplus power grid connection mode, there are: P load ≤P PV (3); SOC ev = 100% (4); If P load = 3 kW, P PV = 4 kW, SOC ev = 100%, SOC limitIf η = 50%, the control system operates in the PV surplus power grid connection mode. The PV power generation of the residence is higher than the household consumption demand, and the electric vehicle battery is fully charged. The surplus PV power is fed back to the grid to obtain profits. When the system is in the PV surplus power grid connection mode, the boost circuit on the PV panel side still uses the voltage and current double closed-loop control strategy to achieve the maximum power point tracking control. The T-type three-level converter operates in the grid connection mode. The grid-side relay is closed, and the load-side relay is open. For the grid connection mode, it is necessary to lock the phase of the grid voltage through a phase-locked loop first. The phase-locked loop module is widely used in this professional field and will not be elaborated. For the control part, the constant current mode control is selected, that is, the current on the inverter side is controlled as the control current loop. Its control block diagram is as Figure 10 shown. By giving the d-axis current, the control of the current magnitude and phase can be achieved. The given current can be calculated through the power and the grid voltage on the inverter side. When the set power P grid_set is positive, the given d-axis current is also positive, and the control output current is in the same phase as the grid voltage, and the energy flows from the PV side to the grid side. Among them, the power given value P grid_set = P PV - P load .

[0045] III. PV and V2H Coordinated Power Supply Mode In the PV and V2H coordinated power supply mode, there are: P PV <P load (5); SOC limit ≤SOC ev ≤100% (6); If P load = 3kW, P PV = 2kW, SOC ev = 100%, SOC limit = 50%, then the control system operates in the PV and V2H coordinated power supply mode. At this time, the PV power generation of the residence is lower than the household consumption demand, and the electric vehicle battery power is higher than the allowable discharge power of the electric vehicle. It is possible to choose the grid or the electric vehicle battery to supply power to the household load according to the electricity price and vehicle use demand. The control strategy of the boost circuit on the PV panel side is the double closed-loop control strategy. The T-type three-level converter operates in the off-grid mode. The bidirectional voltage conversion circuit on the electric vehicle battery side still uses the voltage and current double closed-loop control strategy. The main control objective is to stabilize the DC bus voltage. The power P ev = P load - P PV . At this time, P ev is greater than zero, and the power flows from the electric vehicle battery to the DC bus side, and the battery supplies power to the household load. When the battery power is lower than the allowable discharge power of the electric vehicle, it automatically switches to the grid and PV coordinated charging mode.

[0046] IV. Grid and Photovoltaic Cooperative Charging Mode In the grid and photovoltaic cooperative charging mode, there are: P PV <P load (7); SOC ev <SOC limit (8); If the household scenario is set as P load = 3kW, P PV = 2kW, SOC ev = 40%, SOC limit = 50%, then the control system operates in the grid and photovoltaic cooperative charging mode. At this time, the residential photovoltaic power generation is lower than the household consumption demand, and the electric vehicle battery power is lower than the allowable discharge power of the electric vehicle. Photovoltaic power generation and the grid will jointly charge the electric vehicle. The control strategy of the boost circuit on the photovoltaic panel side remains unchanged, and the household load that cannot be satisfied by the photovoltaic panel can be powered by the grid. The T-type three-level converter operates in the grid-connected mode, the grid-side relay is closed, and the load-side relay is open. Its control strategy is still the constant current control mode, and its control block diagram is as Figure 11 shown. By giving the d-axis current, the control of the current magnitude and phase can be achieved. The given current can be calculated through the power and the grid voltage on the inverter side. At this time, the set power P grid_set is negative, and the given current of the d-axis current is also negative. Energy flows from the grid side to the electric vehicle battery side, where the power given value is P grid_set = P PV - P ev .

[0047] V. Emergency Power Supply Mode In the emergency power supply mode, there are: P PV <P load (9); Flag error = 1 (10); If the household scenario is P load = 3kW, P PV = 2kW, SOC ev = 60%, SOC limit = 50%, and Flag error = 1, Flag error = 1 indicates an emergency failure such as a power outage, then the system operates in the electric vehicle emergency power supply mode. At this time, an emergency power outage occurs. First, photovoltaic power is used. If the photovoltaic power generation is lower than the household consumption demand, regardless of the electric vehicle power, it should be used as an emergency power source for the household. At this time, both the V2H system and the photovoltaic system adopt the double closed-loop control strategy, and the converter module adopts the double closed-loop control and is in the off-grid mode.

[0048] In one embodiment, for example, in the embodiment of the present invention, the method further includes the following steps: If the working mode is the adaptive intelligent regulation mode, control the photovoltaic system to adopt a double closed-loop control strategy, and control both the V2H system and the converter module to adopt power collaborative control; If the working mode is the adaptive intelligent regulation mode, obtain historical data, and balance the household load demand and the electric vehicle battery power demand according to the historical data, the prediction data, and the real-time data, where the historical data includes the charging pile historical data and the household load historical data.

[0049] In the embodiment of the present invention, in the adaptive intelligent regulation mode, the control system can balance the household load demand and the electric vehicle battery circuit demand according to the historical data, the prediction data, and the real-time data. For example, obtain the power prediction data of the in-day photovoltaic power generation and V2H collaborative system of a certain household as Figure 13 shown, and perform adaptive intelligent regulation based on this data as follows: (1) Early morning (00:00 - 05:00) The predicted power of photovoltaic power generation is 0, the predicted power of household load is low, and the user's charging demand is high. The system optimizes the charging power of the charging pile, the V2H system enters the double closed-loop control of the voltage and current of the buck converter circuit in the reverse direction, and the converter module enters the single closed-loop control of the reverse rectification to fully charge the electric vehicle.

[0050] From Figure 14 it can be seen that the three-phase voltage and current waveforms on the AC side of the converter in the rectification mode are symmetrical. Take out the voltage and current of phase A for phase observation. For easy observation, multiply the current amplitude by ten times, and its waveform is as Figure 15 shown. It can be seen that the voltage and current of phase A are out of phase, proving that the converter is working in the rectification mode at this time; (2) Early morning (05:00 - 08:00) The photovoltaic power generation power gradually increases, the household load begins to rise, and the user's charging demand gradually decreases. The system dynamically adjusts the output power of the photovoltaic power generation system and the V2H system. The photovoltaic power generation system uses MPPT control to ensure maximum power output. The V2H system works in the double closed-loop control of the buck converter circuit in the reverse direction, and the converter system enters the single closed-loop control of the reverse rectification. The power set values of the V2H system and the converter system are coordinated and adjusted, and the power set value is gradually reduced on the premise of meeting the charging habits of the user's electric vehicle; (3) Morning and noon (08:00 - 17:00) The photovoltaic power generation continuously increases to reach the peak and meets the household load demand. The household load fluctuates, and the user charging demand is relatively low. The system preferentially uses the photovoltaic electric energy to supply power to the household load. If the photovoltaic electric energy is sufficient, the system will feed the excess electric energy back to the grid. The photovoltaic power generation system uses MPPT control to ensure the maximum power output. The converter system smoothly switches from the reverse rectification single closed-loop control to the inversion mode, and in the inversion mode, it smoothly switches between the grid-connected and off-grid modes according to the surplus of the photovoltaic power generation.

[0051] As Figure 16 shown are the three-phase output voltage and current waveforms. The three-phase grid-connected voltage and current waveforms before and after the mode switch are symmetrically distributed. Take out the voltage and current of phase A for phase observation. For convenient observation, multiply the current amplitude by ten times. Its waveform is as Figure 17 shown. It can be seen from the figure that the voltage and current of phase A are out of phase before the switch and in phase after the switch, which proves that the energy storage converter successfully switches from the rectification mode to the inversion mode, and the switching process is relatively stable. Using the zero-sequence vector control based on positive and negative sequence separation and virtual orthogonality construction, with a three-phase unbalanced load on the off-grid side, its three-phase output voltage and current are as Figure 18 shown. It can be seen from the figure that the three-phase voltage unbalance degree is greatly reduced.

[0052] The waveform diagram of the three-phase output voltage and current of the converter is as shown in Figure 19. It can be known from Figure 19 that when switching between the grid-connected and off-grid modes, the fluctuations of the three-phase output voltage and current of the energy storage converter quickly return to normal within two cycles, and the power supply is relatively reliable; (4) Evening (17:00 - 20:00) The photovoltaic power generation continuously decreases. The household load reaches the peak, and the user charging demand is relatively high. The system dynamically adjusts the output power of the photovoltaic power generation system and the V2H system. The photovoltaic power generation system uses MPPT control to ensure the maximum power output. The V2H system operates in the double closed-loop control of the reverse Buck circuit. The converter system smoothly switches from the forward inversion mode to the reverse rectification single closed-loop control, and continuously increases the power set value of the V2H system.

[0053] As Figure 20 shown are the three-phase output voltage and current waveforms. The three-phase grid-connected voltage and current waveforms before and after the mode switch are symmetrically distributed. Take out the voltage and current of phase A for phase observation. For convenient observation, multiply the current amplitude by ten times. Its waveform is as Figure 21 shown. It can be seen from the figure that the voltage and current of phase A are in phase before the switch and out of phase after the switch, which proves that the energy storage converter successfully switches from the inversion mode to the rectification mode, and the switching process is relatively stable; (5) Night (20:00 - 24:00) The photovoltaic power generation is close to 0, the household load gradually decreases, and the charging pile is in a high-power charging state. The system optimizes the charging power of the charging pile. The V2H system enters the double closed-loop control of voltage and current of the buck converter in reverse, and the converter system enters the single closed-loop control of reverse rectification to fully charge the electric vehicle. At this time, the photovoltaic power generation prediction and household load power consumption prediction for the next day can be carried out, and at the same time, preparations are made to welcome the operation of the next cycle.

[0054] The photovoltaic power generation and V2H collaborative control system based on multi-mode switching and its control method disclosed in the present invention can obtain prediction data and combine real-time data and electric vehicle data to confirm the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching and the collaborative control strategy matching the working mode, so as to balance the household load demand and the electric vehicle battery power demand, and improve the utilization rate of the photovoltaic system and the stability of household load power supply.

[0055] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A photovoltaic power generation and V2H collaborative control system based on multi-mode switching, characterized in that: include: A V2H system, wherein the V2H system is connected to a DC bus; A photovoltaic system, wherein the photovoltaic system is connected to the DC bus; A converter module, wherein the DC side of the converter is connected to the DC bus, and the AC side of the converter is connected to the power grid and the household load respectively.

2. The photovoltaic power generation and V2H coordinated control system based on multi-mode switching according to claim 1 is characterized in that: The V2H system includes an electric vehicle battery and a bidirectional voltage conversion circuit; The electric vehicle battery is connected to the bidirectional voltage conversion circuit, and the bidirectional voltage conversion circuit is connected to the DC bus.

3. The photovoltaic power generation and V2H coordinated control system based on multi-mode switching according to claim 1 is characterized in that: The photovoltaic system includes a photovoltaic panel and a boost circuit; The photovoltaic panel is connected to the boost circuit, and the boost circuit is connected to the DC bus.

4. The photovoltaic power generation and V2H coordinated control system based on multi-mode switching according to claim 1 is characterized in that: The converter module includes a grid-connected three-level converter circuit and an off-grid three-level converter circuit; The DC side of the grid-connected three-level converter circuit and the DC side of the off-grid three-level converter circuit are both connected to the DC bus, the AC side of the grid-connected three-level converter circuit is connected to the grid, and the AC side of the off-grid three-level converter circuit is connected to the household load.

5. A control method, characterized in that: Used to control the photovoltaic power generation and V2H coordinated control system based on multi-mode switching according to any one of claims 1 to 4, the method comprising: Acquire real-time data, predicted data and electric vehicle data of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching, wherein the real-time data includes the real-time power of household photovoltaic power generation and the real-time power of household load, the predicted data includes the predicted household photovoltaic power generation and the predicted household load power, and the electric vehicle data includes the battery power of the electric vehicle and the allowable discharge power of the electric vehicle; Confirming the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching and the collaborative control strategy matching the working mode according to the predicted data, the real-time data and the electric vehicle data; The photovoltaic power generation and V2H collaborative control system based on multi-mode switching is controlled according to the confirmed working mode and a collaborative control strategy matching the working mode to balance the household load demand and the electric vehicle battery power demand.

6. The method according to claim 5, characterized in that The working mode includes a fixed working mode and an adaptive intelligent control mode, and the method further includes: confirming the difference between the predicted data and the real-time data; If the difference between the predicted data and the real-time data is greater than a first preset threshold, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the fixed working mode; If the difference between the predicted data and the real-time data is less than or equal to the first preset threshold, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the adaptive intelligent control mode.

7. The method according to claim 6, characterized in that The fixed working modes include photovoltaic priority charging mode, photovoltaic surplus power access mode, photovoltaic and V2H collaborative power supply mode, power grid and photovoltaic collaborative charging mode and electric vehicle emergency power supply mode, and the method further includes: If the real-time power of the household photovoltaic power generation is greater than the real-time power of the household load, and the battery of the electric vehicle is not fully charged, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the photovoltaic priority charging mode; If the real-time power of the household photovoltaic power generation is greater than the real-time power of the household load, and the battery of the electric vehicle is fully charged, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the photovoltaic surplus power access mode; If the real-time power of the household photovoltaic power generation is less than or equal to the real-time power of the household load, and the battery power of the electric vehicle is greater than the allowable discharge power of the electric vehicle, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the photovoltaic and V2H collaborative power supply mode; If the real-time power of the household photovoltaic power generation is less than or equal to the real-time power of the household load, and the battery power of the electric vehicle is less than or equal to the allowable discharge power of the electric vehicle, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the grid and photovoltaic collaborative charging mode; If a power outage is detected and the real-time power of the household photovoltaic power generation is less than or equal to the real-time power of the household load, the working mode of the photovoltaic power generation and V2H collaborative control system based on multi-mode switching is switched to the electric vehicle emergency power supply mode.

8. The method according to claim 7, characterized in that The method further comprises: If the working mode is the photovoltaic priority charging mode, the V2H system, the photovoltaic system and the converter module are all controlled to adopt a double closed-loop control strategy, and the converter module is controlled to be in an off-grid mode; If the working mode is the photovoltaic surplus power grid-connected mode, the V2H system is controlled not to work, the photovoltaic system is controlled to adopt a double closed-loop control strategy, and the converter module is controlled to adopt a single closed-loop control and be in a grid-connected mode; If the working mode is the photovoltaic and V2H collaborative power supply mode, the V2H system and the photovoltaic system are both controlled to adopt a dual closed-loop control strategy, and the converter module is controlled to adopt a dual closed-loop control and be in an off-grid mode; If the working mode is the grid and photovoltaic cooperative charging mode, the V2H system is controlled not to work, the photovoltaic system is controlled to adopt a double closed-loop control strategy, and the converter module is controlled to adopt a double closed-loop control and be in an off-grid mode; If the working mode is the electric vehicle emergency power supply mode, the V2H system and the photovoltaic system are both controlled to adopt a dual closed-loop control strategy, and the converter module is controlled to adopt a dual closed-loop control and be in an off-grid mode.

9. The method according to claim 6, characterized in that The method further comprises: If the working mode is the adaptive intelligent control mode, the photovoltaic system is controlled to adopt a dual closed-loop control strategy, and the V2H system and the converter module are controlled to adopt power coordinated control.

10. The method according to claim 6, characterized in that The method further comprises: If the working mode is the adaptive intelligent control mode, historical data is obtained, and the household load demand and the electric vehicle battery power demand are balanced according to the historical data, the predicted data and the real-time data, wherein the historical data includes charging pile historical data and household load historical data.

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