Dual-use, full-operation-condition topology self-switching island-supported energy router

Abstract

The present invention provides a dual-multiplexed, full-operating-condition topology self-switching, island-supported energy router, relating to the field of power electronics technology. The router includes a three-phase PWM rectifier unit, a three-phase PWM inverter unit, a bidirectional DC / DC converter unit, a first bidirectional buck-boost converter unit, a second bidirectional buck-boost converter unit, and a third bidirectional buck-boost converter unit. The ports of the dual-multiplexed, full-operating-condition topology self-switching island-supported energy router are respectively connected to a generator, a photovoltaic panel, a battery pack, a supercapacitor, an AC load, and a DC load. The router adjusts the operating mode of the energy router according to the remaining capacity of the battery pack connected to the external port, performs charging and discharging operations by determining the remaining capacity of the battery pack, and can dynamically adjust the remaining capacity between the batteries within the battery pack. The energy router can also control the output voltage of the photovoltaic panel connected to the external port by multiplexing the three-phase PWM rectifier unit, so that the photovoltaic panel always maintains the maximum operating voltage.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to an island-supported energy router with dual-multiplexing and full-operating-condition topology self-switching. Background Art

[0002] With China's increasing emphasis on clean energy and its strong support for pollution-free, sustainable renewable energy, the rise of renewable energy sources like solar power is inevitable. The concept of the energy router was first proposed and successfully applied in the Energy Internet. In this context, the energy router is an intelligent entity that integrates the cyber-physical systems of the power grid, featuring computing, communication, precise control, remote coordination, autonomy, and universal plug-and-play access. Applying the energy router from high voltage to low voltage, and from the Energy Internet to in-vehicle microgrids, has enabled efficient energy utilization and improved energy efficiency. Furthermore, the energy router's multiple ports, allowing for the independent definition of their functions, increase its practicality, enrich energy flow, and enhance battery life.

[0003] When the island-supported energy router operates independently, it is not connected to the grid and stores electrical energy through batteries and supercapacitors. The design idea of ​​the island-supported energy router is to achieve the goal of improving the portability of the energy router, reducing the size of the energy router and thus saving space. This design is mainly achieved by reusing the topological structure of the energy router and changing the working mode by self-switching to achieve different working states of the energy router, thereby improving the practicality of the island-supported energy router.

[0004] Currently, traditional energy routers with solid-state transformers as their core have difficulty adapting to complex working conditions, are unable to select appropriate working modes for different external loads, and have low energy conversion efficiency. Due to the hardware topology limitations of traditional energy routers, most of the working units of the energy routers are independent of each other, making it impossible to reduce the size of the device and improve its portability. Due to the single control method of traditional solid-state transformers, it is impossible to coordinate the battery packs connected to the external ports to optimize the distribution of transmitted electricity, making it difficult to meet the requirements of improving battery utilization. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a topological structure and working mode of an island-supported energy router with dual-multiplexing full-working-condition topology self-switching. The topological structure of the multiplexed energy router is used to realize the control of the photovoltaic panels of the external ports through the multiplexed rectifier unit, and the different working states of the energy router can be realized by changing the working mode through self-switching, thereby improving the practicality of the island-supported energy router.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a dual-multiplexed, full-operating-condition topology self-switching island-supported energy router, comprising a three-phase PWM rectifier unit, a three-phase PWM inverter unit, a bidirectional DC / DC converter unit, a first bidirectional buck-boost converter unit, a second bidirectional buck-boost converter unit, and a third bidirectional buck-boost converter unit; each port of the dual-multiplexed, full-operating-condition topology self-switching island-supported energy router is respectively connected to a generator, a photovoltaic panel, a battery pack, a supercapacitor, an AC load, and a DC load; the battery pack includes three batteries;

[0007] The input end of the three-phase PWM rectifier unit is connected to the generator to obtain an AC power supply as an input power supply; the output end of the three-phase PWM rectifier unit is connected to the input end of the bidirectional DC / DC conversion unit; the output end of the three-phase PWM rectifier unit is also connected to the output end of the photovoltaic panel; the output end of the photovoltaic panel is connected to the battery pack; the output end of the bidirectional DC / DC conversion unit is connected to the input end of the three-phase PWM inverter unit; the output end of the three-phase PWM inverter unit is connected to the AC load; the input end of the first bidirectional BUCK-BOOST conversion unit, the input end of the second bidirectional BUCK-BOOST conversion unit, and the input end of the third bidirectional BUCK-BOOST conversion unit are all connected to the battery pack The output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, and the output end of the third bidirectional buck-boost conversion unit are all connected to the three-phase PWM inverter unit; the output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, and the output end of the third bidirectional buck-boost conversion unit are all connected to the output end of the supercapacitor; the output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, the output end of the third bidirectional buck-boost conversion unit, and the output end of the supercapacitor are all connected to a DC load.

[0008] Preferably, the island-supported energy router adjusts the working mode of the energy router according to the remaining capacity of the battery pack connected to the external port, performs charging and discharging operations by judging the remaining capacity of the battery pack, and can dynamically adjust the remaining capacity between the batteries within the battery pack. The energy router can also control the output voltage of the photovoltaic panel connected to the external port by multiplexing the three-phase PWM rectifier unit, so that the photovoltaic panel always maintains the maximum operating voltage.

[0009] Preferably, the method for calculating the remaining capacity of the battery pack is specifically as follows:

[0010] (1) Based on the load index, energy utilization rate and anti-interference ability of the island-supported energy router, a dynamic remaining capacity calculation function f(t) of the battery pack with time t as the dependent variable is established, as shown in the following formula:

[0011]

[0012] Among them, K>0 is the index coefficient of the load borne by the energy router; α>0 is the energy utilization coefficient of the energy router; β>0 is the anti-interference ability coefficient of the energy router, p x (t), p y (t) are the total input power and total output power of the energy router at time t, as shown in the following formula:

[0013] p x (t) = p1(t) + p2(t)p y (t) = p1(t) + p2(t) + p3(t)

[0014] Among them, p1(t), p2(t), p3(t), p4(t), and p5(t) are the generator input power, photovoltaic panel port input power, AC load terminal output power, DC load terminal output power, and battery terminal output power at time t, respectively; T(t), T o ,、T * (t) and S1, respectively, are the ambient temperature, preset working ambient temperature, optimal working ambient temperature, and energy regulation coefficient of the island-supported energy router at time t;

[0015] (2) Establishing optimization conditions for the dynamic remaining capacity calculation function f(t) of the battery pack, solving the three index functions f1(p1, p2), energy utilization function f2(p1, p2, p3, p4, p5), and anti-interference ability function f3(p5) of the load borne by the island support type energy router, and obtaining (p1, p2, p3, p4, p5), (p1, p2, p3, p4, p5) (2) ,(p1,p2,p3,p4,p5) (3) The single indicator under three sets of constraints is optimal;

[0016] (3) According to the optimal single indicator under the three sets of constraints, the maximum value M of the optimal solution corresponding to each indicator is obtained i And the minimum value m in the optimal solution corresponding to each indicator i , determine the weighting coefficient of each indicator in, i=1,2,3;

[0017] (4) Further construct the linear programming problem L(1) based on the sum μ of load index, energy utilization rate and anti-interference ability:

[0018]

[0019] Where R represents a real number;

[0020] By solving the linear programming problem L(1), we can get the ideal solution of (p1, p2, p3, p4, p5), and bring the ideal solution into the three indicator functions for comparison. If the deviation of each indicator is less than the set threshold of 3%, then the M corresponding to the required indicator will be replaced. i Increase by 3%; if the deviation of each indicator is greater than the set threshold of 3%, the M corresponding to the required indicator will be increased. i Reduce by 3%, and restructure the planning problem L(2) again, as shown in the following formula:

[0021]

[0022] Then solve the linear programming problem L(2), repeatedly compare whether the deviation of each indicator satisfies the deviation less than the set threshold of 3%. If not, repeat until a set of actual ideal solutions (p1, p2, p3, p4, p5) is output, and substitute it into the dynamic remaining capacity calculation function of the battery pack f(t), which is the current dynamic remaining capacity calculation function of the battery pack; then judge the remaining capacity of the battery pack. If the remaining capacity of each battery is greater than or equal to 95% of the rated capacity, the battery supplies power to the outside; if the remaining capacity of each battery is less than 95% of the rated capacity, the photovoltaic panel charges the battery.

[0023] Preferably, the multiplexing of the three-phase PWM rectifier unit, i.e., controlling the photovoltaic panels connected to the external ports of the three-phase PWM rectifier unit, is specifically performed as follows:

[0024] The photovoltaic panel supplies power to the battery pack, and the output of the photovoltaic panel is connected to the battery pack. At the same time, the battery pack is disconnected from the input of the first bidirectional buck-boost conversion unit, the input of the second bidirectional buck-boost conversion unit, and the input of the third bidirectional buck-boost conversion unit. The remaining working units remain unchanged.

[0025] Then, the MPPT algorithm is used to continuously collect the voltage and current of the photovoltaic panel output three times at a certain moment, and the output power of the photovoltaic panel is calculated based on the three collected voltage and current values. The tracking direction of the photovoltaic panel output voltage is determined by judging the change trend of the three photovoltaic panel output power; the value of the working voltage at the maximum output power of the predicted photovoltaic panel is used as the voltage reference value of the output end of the three-phase PWM rectifier unit, and substituted into the voltage reference value and actual voltage comparison link in the voltage outer loop of the voltage and current double closed loop during the rectification process of the three-phase PWM rectifier unit to control the voltage of the output end of the three-phase PWM rectifier unit, so that the output end voltage of the three-phase PWM rectifier unit changes towards the reference voltage.

[0026] Preferably, the island support type energy router selects different working modes according to the remaining capacity of the battery pack. The specific method is as follows: the external load power connected to the battery pack is set to P1, and the rated output power of a single bidirectional BUCK-BOOST conversion unit is P v , the battery pack and supercapacitor supply power to the load. At this time, the working status of the battery pack includes the following situations:

[0027] 1. Determine whether the rated output power of a single bidirectional BUCK-BOOST conversion unit can meet the external load power connected to the battery pack. If the external load power P1 is less than or equal to the rated output power P of the bidirectional BUCK-BOOST conversion unit, v , then the island support type energy router enters working mode 1:

[0028] The photovoltaic panel is disconnected from the battery pack. The batteries in the battery pack operate in series, and power is supplied to the load via the first bidirectional buck-boost converter. The output of the first bidirectional buck-boost converter is connected to the output of the supercapacitor. The second and third bidirectional buck-boost converters do not supply power to the load.

[0029] 2. Determine whether the rated output power of the two bidirectional BUCK-BOOST conversion units can meet the external load power connected to the battery pack. If the external load power P1 is less than or equal to twice the rated output power 2P of the bidirectional BUCK-BOOST conversion unit, v , then the island support type energy router enters working mode 2:

[0030] The photovoltaic panel is disconnected from the battery pack. Two batteries 2 and 3 in the battery pack are connected in series and then pass through the second bidirectional buck-boost converter unit. The other battery 1 passes through the first bidirectional buck-boost converter unit to supply power to the load. The output terminals of the first and second bidirectional buck-boost converter units are connected to the output terminal of the supercapacitor. Meanwhile, the third bidirectional buck-boost converter unit does not participate in supplying power to the load.

[0031] 3. Determine whether the rated output power of the three bidirectional buck-boost converter units is not greater than three times the rated output power (3P) of the bidirectional buck-boost converter units. v , if it meets the requirements, the island support type energy router enters working mode 3:

[0032] The photovoltaic panel is disconnected from the battery pack. First battery 1 is connected to the first bidirectional buck-boost conversion unit, second battery 2 is connected to the second bidirectional buck-boost conversion unit, and third battery 3 is connected to the third bidirectional buck-boost conversion unit. The output ends of the first, second, and third bidirectional buck-boost conversion units are connected in parallel to supply power to the load. To ensure the stability of power supply to the load, the output ends of the first, second, and third bidirectional buck-boost conversion units are connected to the output end of the supercapacitor.

[0033] Preferably, the remaining capacity of the battery pack connected to the external port of the energy router is adjusted as follows:

[0034] Determine the remaining capacity of each battery in the battery pack. If the remaining capacity of each battery is greater than or equal to the set rated capacity, the battery pack enters operating mode A. If the remaining capacity of any battery is less than the set rated capacity, the battery pack enters operating mode B.

[0035] Working mode A:

[0036] Monitor the dynamic remaining capacity of each battery and calculate the average SOC value of the battery pack port Define the imbalance degree of SOC of the k-port of the battery pack as ΔSOC (k) , define the output power target value of each port of the battery pack and current reference value I (k)-ref Based on the average power of each port of the battery pack, the power deviation is adjusted according to the SOC imbalance of the battery pack to obtain the battery pack port current reference value I(k)-ref And the real-time power transmission value P of the battery group port (k)-ref , as shown below:

[0037]

[0038]

[0039] Among them, V (k) is the output voltage value of the battery pack k port, is the target output power value of the battery group port, K a is the proportionality coefficient;

[0040] The output power of the batteries is controlled again so that the SOC values ​​of the batteries remain equal;

[0041] Working mode B:

[0042] At this time, there is a battery in a deep discharge state. Disconnect the battery from the external load to wait for charging. Determine the number of batteries that can work normally, n, n < 3, and define the imbalance of each battery SOC as ε i , set the imbalance threshold ε m , construct the SOC imbalance diagonal matrix A of the battery pack as shown below:

[0043]

[0044] The elements ε in the diagonal matrix A are i The absolute value of ε m Compare, if A does not exist |ε i |>ε m elements, then the SOC of each battery remains balanced and the battery pack maintains its current output power unchanged; if there is |ε in A i |>ε m The elements of , calculated based on ε i Battery power distribution mode P i , get the diagonal matrix P of the power distribution mode of the battery pack refi , as shown in the following formula:

[0045]

[0046] Among them, K α Represents the temperature influence coefficient of the battery.

[0047] As the battery pack operates, the value of A is constantly updated, and the maximum value of the imbalance degree of each battery ε MAXThe balanced state of the SOC of each battery is determined so that the battery can obtain a reasonable output power control method. After the photovoltaic panel has completed charging the battery, the deeply discharged battery is reconnected and the battery pack can supply power normally.

[0048] The beneficial effects of adopting the above technical solution are: the topological structure and working mode of a dual-multiplexing, full-operating-condition topology self-switching island-supported energy router provided by the present invention, (1) realize the reuse function of the rectifier unit, improve the working efficiency of the photovoltaic panel through topological reuse, and can also optimize the topological structure, improve the power density of the energy router, and enhance the portability and practicality of the dual-multiplexing, full-operating-condition topology self-switching island-supported energy router, providing basic conditions for the miniaturization development of the energy router; (2) according to the remaining capacity of the battery pack connected to the external port, the energy router can select different working modes to adapt to different complex working conditions This measure can improve the efficiency of the battery's external power supply and maintain the normal operation of the island-supported energy router with dual-use full-working-condition topology self-switching; (3) For the battery group connected to the external port, the working state of the battery under different residual capacity is set, the dynamic residual capacity of the battery group is monitored, the residual capacity between each battery is automatically adjusted, and the power distribution and transmission of the battery is optimized, that is, when the battery group is working, the output power of each battery is changed to maintain the dynamic balance of the capacity between each battery, which can greatly reduce the number of deep discharges of the battery, thereby extending the working life of the battery and improving the operational reliability of the energy router. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A structural block diagram of a dual-multiplexing, full-operating-condition topology self-switching island-supported energy router provided by an embodiment of the present invention;

[0050] Figure 2 A topological diagram of a dual-multiplexing, full-operation-condition topology self-switching, island-supported energy router provided by an embodiment of the present invention;

[0051] Figure 3 A topological diagram of the energy router provided by an embodiment of the present invention when entering working mode 1;

[0052] Figure 4 A topological diagram of the energy router provided by an embodiment of the present invention when entering working mode 2;

[0053] Figure 5 A topological diagram of the energy router provided by an embodiment of the present invention when entering working mode 3;

[0054] Figure 6 This is a topology diagram of the energy router provided in an embodiment of the present invention when it enters working mode B. DETAILED DESCRIPTION

[0055] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0056] In this embodiment, a dual-multiplexed full-operation topology self-switching island support type energy router is provided. Figure 1 、 2 As shown, it includes a three-phase PWM rectifier unit, a three-phase PWM inverter unit, a bidirectional DC / DC conversion unit, a first bidirectional BUCK-BOOST conversion unit, a second bidirectional BUCK-BOOST conversion unit, and a third bidirectional BUCK-BOOST conversion unit; each port of the dual-multiplexing full-operating-condition topology self-switching island-supported energy router is respectively connected to a generator, a photovoltaic panel, a battery pack, a supercapacitor, an AC load, and a DC load; the battery pack includes three batteries;

[0057] The input end of the three-phase PWM rectifier unit is connected to the generator to obtain an AC power supply as an input power supply; the output end of the three-phase PWM rectifier unit is connected to the input end of the bidirectional DC / DC conversion unit; the output end of the three-phase PWM rectifier unit is also connected to the output end of the photovoltaic panel; the output end of the photovoltaic panel is connected to the battery pack; the output end of the bidirectional DC / DC conversion unit is connected to the input end of the three-phase PWM inverter unit; the output end of the three-phase PWM inverter unit is connected to the AC load; the input end of the first bidirectional BUCK-BOOST conversion unit, the input end of the second bidirectional BUCK-BOOST conversion unit, and the input end of the third bidirectional BUCK-BOOST conversion unit are all connected to the battery pack The output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, and the output end of the third bidirectional buck-boost conversion unit are all connected to the three-phase PWM inverter unit; the output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, and the output end of the third bidirectional buck-boost conversion unit are all connected to the output end of the supercapacitor; the output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, the output end of the third bidirectional buck-boost conversion unit, and the output end of the supercapacitor are all connected to a DC load.

[0058] The island-supported energy router adjusts its operating mode based on the remaining capacity of the battery pack connected to the external port. It performs charging and discharging operations by determining the remaining capacity of the battery pack, and the remaining capacity can be dynamically adjusted between the batteries within the battery pack. The energy router can also control the output voltage of the photovoltaic panel connected to the external port by multiplexing the three-phase PWM rectifier unit, ensuring that the photovoltaic panel always maintains the maximum operating voltage.

[0059] The method for calculating the remaining capacity of the battery pack is specifically as follows:

[0060] (1) Based on the load index, energy utilization rate and anti-interference ability of the island-supported energy router, a dynamic remaining capacity calculation function f(t) of the battery pack with time t as the dependent variable is established, as shown in the following formula:

[0061]

[0062] Among them, K>0 is the index coefficient of the load borne by the energy router; α>0 is the energy utilization coefficient of the energy router; β>0 is the anti-interference ability coefficient of the energy router, p x (t), p y (t) are the total input power and total output power of the energy router at time t, as shown in the following formula:

[0063] p x (t) = p1(t) + p2(t)p y (t) = p1(t) + p2(t) + p3(t)

[0064] Among them, p1(t), p2(t), p3(t), p4(t), and p5(t) are the generator input power, photovoltaic panel port input power, AC load terminal output power, DC load terminal output power, and battery terminal output power at time t, respectively; T(t), T o ,、T * (t) and S1, respectively, are the ambient temperature, preset working ambient temperature, optimal working ambient temperature, and energy regulation coefficient of the island-supported energy router at time t;

[0065] (2) Establishing optimization conditions for the dynamic remaining capacity calculation function f(t) of the battery pack, solving the three index functions f1(p1, p2), energy utilization function f2(p1, p2, p3, p4, p5), and anti-interference ability function f3(p5) of the load borne by the island support type energy router, and obtaining (p1, p2, p3, p4, p5), (p1, p2, p3, p4, p5) (2) ,(p1,p2,p3,p4,p5) (3) The single indicator under three sets of constraints is optimal;

[0066] The index function f1(p1, p2) of the load borne by the island-supported energy router is:

[0067]

[0068] The energy utilization function f2(p1, p2, p3, p4, p5) is:

[0069]

[0070] The anti-interference capability function f3(p5) is:

[0071]

[0072] The following optimization conditions are established for the dynamic remaining capacity calculation function f(t) of the battery pack:

[0073]

[0074] Where η1, η2, η3, η4, and η5 are the conversion efficiencies of the photovoltaic panels, supercapacitors, battery packs, DC loads, and AC loads to the DC bus on the load side. Optimal control is achieved when the constraints are met and the multi-objective optimization value of the energy router reaches the maximum. U C is the reference value of the DC bus voltage on the load side and the actual value of the DC bus voltage on the load side; 1MAX ,p 2MAX ,p 3MAX ,p 4MAX ,p 5MAX is the maximum input power of the photovoltaic end, the maximum input power of the motor port, the maximum output power of the AC load end, the maximum output power of the DC load end, and the maximum output power of the supercapacitor;

[0075] (3) According to the optimal single indicator under the three sets of constraints, the maximum value M of the optimal solution corresponding to each indicator is obtained i And the minimum value m in the optimal solution corresponding to each indicator i , determine the weighting coefficient of each indicator in, i=1,2,3;

[0076] (4) Further construct the linear programming problem L(1) based on the sum μ of load index, energy utilization rate and anti-interference ability:

[0077]

[0078] Where R represents a real number;

[0079] By solving the linear programming problem L(1), we can get the ideal solution of (p1, p2, p3, p4, p5), and bring the ideal solution into the three indicator functions for comparison. If the deviation of each indicator is less than the set threshold of 3%, then the M corresponding to the required indicator will be replaced. i Increase by 3%; if the deviation of each indicator is greater than the set threshold of 3%, the M corresponding to the required indicator will be increased. i Reduce by 3%, and restructure the planning problem L(2) again, as shown in the following formula:

[0080]

[0081] Then solve the linear programming problem L(2), repeatedly compare whether the deviation of each indicator satisfies the deviation less than the set threshold of 3%. If not, repeat until a set of actual ideal solutions (p1, p2, p3, p4, p5) is output, and substitute it into the dynamic remaining capacity calculation function of the battery pack f(t), which is the current dynamic remaining capacity calculation function of the battery pack; then judge the remaining capacity of the battery pack. If the remaining capacity of each battery is greater than or equal to 95% of the rated capacity, the battery supplies power to the outside; if the remaining capacity of each battery is less than 95% of the rated capacity, the photovoltaic panel charges the battery.

[0082] The multiplexing of the three-phase PWM rectifier unit, that is, controlling the photovoltaic panels connected to the external ports of the three-phase PWM rectifier unit, is specifically performed as follows:

[0083] The photovoltaic panel supplies power to the battery pack, and the output of the photovoltaic panel is connected to the battery pack. At the same time, the battery pack is disconnected from the input of the first bidirectional buck-boost conversion unit, the input of the second bidirectional buck-boost conversion unit, and the input of the third bidirectional buck-boost conversion unit. The remaining working units remain unchanged.

[0084] Then, an MPPT algorithm based on a power prediction strategy is adopted. The voltage and current at the output end of the photovoltaic panel are continuously collected three times at a certain moment. The output power of the photovoltaic panel is calculated based on the three collected voltage and current values. The tracking direction of the photovoltaic panel output voltage is determined by judging the change trend of the three photovoltaic panel output power; the predicted working voltage value at the maximum output power of the photovoltaic panel is used as the voltage reference value of the output end of the three-phase PWM rectifier unit, and substituted into the voltage reference value and actual voltage comparison link in the voltage outer loop of the voltage and current double closed loop during the rectification process of the three-phase PWM rectifier unit to control the voltage at the output end of the three-phase PWM rectifier unit, so that the output end voltage of the three-phase PWM rectifier unit changes towards the reference voltage, that is, the output end voltage of the three-phase PWM rectifier unit approaches the working voltage at the maximum output power of the photovoltaic panel. The specific calculation method is as follows:

[0085] First, collect the current maximum operating current I1 of the photovoltaic panel, the short-circuit current I2 of the photovoltaic panel, the maximum operating voltage U1 of the photovoltaic panel, and the open-circuit voltage U2 of the photovoltaic panel;

[0086] Then calculate the maximum output current I3 of the photovoltaic panel and the correction coefficients C1 and C2 as shown in the following formula:

[0087]

[0088] The output power model P of the photovoltaic panel is solved according to the calculated correction coefficient, as shown in the following formula:

[0089]

[0090] Therefore, the three-phase PWM rectifier unit can be used to control the photovoltaic panel to always maintain the maximum output power. This feature will be used in the battery's operating mode B.

[0091] The island support type energy router selects different working modes according to the remaining capacity of the battery pack. The specific method is as follows: the external load power connected to the battery pack is set to P1, and the rated output power of a single bidirectional BUCK-BOOST conversion unit is P v , the battery pack and supercapacitor supply power to the load. At this time, the working status of the battery pack includes the following situations:

[0092] 1. Determine whether the rated output power of a single bidirectional BUCK-BOOST conversion unit can meet the external load power connected to the battery pack. If the external load power P1 is less than or equal to the rated output power P of the bidirectional BUCK-BOOST conversion unit, v , that is, P1<=P v , then the island-supported energy router enters working mode 1:

[0093] like Figure 3 As shown, switches 3, 5, 6, and 8 are open, and switches 1, 2, 4, 7, and 9 are closed. The photovoltaic panel is disconnected from the battery pack, and the batteries in the battery pack operate in series. Power is supplied to the load via the first bidirectional buck-boost converter unit. The output of the first bidirectional buck-boost converter unit is connected to the output of the supercapacitor. Meanwhile, the second and third bidirectional buck-boost converter units do not participate in supplying power to the load.

[0094] 2. Determine whether the rated output power of the two bidirectional BUCK-BOOST conversion units can meet the external load power connected to the battery pack. If the external load power P1 is less than or equal to twice the rated output power 2P of the bidirectional BUCK-BOOST conversion unit, v , that is, P v<P1<=2P v , then the island support type energy router enters working mode 2:

[0095] like Figure 4 As shown, switches 4, 6, and 8 are open, and switches 1, 2, 3, 5, 7, and 9 are closed. The photovoltaic panel is disconnected from the battery pack. Two batteries 2 and 3 in the battery pack are connected in series and then pass through the second bidirectional buck-boost conversion unit. The other battery 1 passes through the first bidirectional buck-boost conversion unit to supply power to the load. The output terminals of the first and second bidirectional buck-boost conversion units are connected to the output terminal of the supercapacitor. At the same time, the third bidirectional buck-boost conversion unit does not participate in supplying power to the load.

[0096] 3. Determine whether the rated output power of the three bidirectional buck-boost converter units is not greater than three times the rated output power (3P) of the bidirectional buck-boost converter units. v , that is, 2P v <P1<=3P v , if it meets the requirements, the island support type energy router enters working mode 3:

[0097] like Figure 5 As shown, switches 4 and 7 are opened, and switches 1, 2, 3, 5, 6, 8, and 9 are closed. The photovoltaic panel is disconnected from the battery pack, and the first battery 1 is connected to the first bidirectional buck-boost conversion unit, the second battery 2 is connected to the second bidirectional buck-boost conversion unit, and the third battery 3 is connected to the third bidirectional buck-boost conversion unit. The output ends of the first, second, and third bidirectional buck-boost conversion units are connected in parallel to supply power to the load. To ensure the stability of the power supply to the load, the output ends of the first, second, and third bidirectional buck-boost conversion units are connected to the output end of the supercapacitor.

[0098] The method for adjusting the remaining capacity of the battery pack connected to the external port of the energy router is as follows:

[0099] Determine the remaining capacity of each battery in the battery pack. If the remaining capacity of each battery is greater than or equal to the set rated capacity, the battery enters operating mode A. If the remaining capacity of any battery is less than the set rated capacity, the battery enters operating mode B.

[0100] Working mode A:

[0101] When the battery is working in working mode A, the energy router maintains normal operation and still changes between working mode 1, working mode 2, and working mode 3. At this time, the dynamic remaining capacity of each battery is monitored to obtain the average SOC value of the battery pack port. The imbalance degree of SOC of the k-port of the battery pack is defined as Define the output power target value of each port of the battery pack and current reference value I (k)-ref Based on the average power of each port of the battery pack, the power deviation is adjusted according to the SOC imbalance of the battery pack to obtain the battery pack port current reference value I (k)-ref And the real-time power transmission value P of the battery group port (k)-ref , as shown below:

[0102]

[0103]

[0104] Among them, V (k) is the output voltage value of the battery pack k port, is the target output power value of the battery group port, K a is the specific proportional coefficient obtained through calculation;

[0105] Then the battery pack port current reference value I (k)-ref And the real-time power transmission value P of the battery group port (k)-ref The application performs output power control with the battery so that the SOC values ​​of each battery tend to be the same;

[0106] Working mode B:

[0107] At this time, there are batteries in a deep discharge state. Disconnect the battery from the external load to wait for charging. Determine the number of batteries n with SOC greater than 20% and working normally, where n is less than 3. Define the imbalance degree of each battery SOC as ε i , whose value is the SOC of battery i i and the average SOC of each battery avg The difference between SOC avg The ratios are as follows:

[0108]

[0109]

[0110] Set the imbalance threshold ε m , construct the SOC imbalance diagonal matrix A of the battery pack as shown below:

[0111]

[0112] The elements ε in the diagonal matrix A are i The absolute value of ε m Compare, if A does not exist |ε i |>ε m elements, then the SOC of each battery remains balanced and the battery pack maintains its current output power unchanged; if there is |ε in A i |>ε m The elements of , calculated based on ε i Battery power distribution method Get the diagonal matrix P of the power distribution mode of the battery pack refi , as shown in the following formula:

[0113]

[0114] Among them, K α , K β Represents the temperature influence coefficient and force majeure error coefficient of the battery.

[0115] As the battery pack operates, the value of A is constantly updated, and the maximum value of the imbalance degree of each battery ε MAX Determine the balanced state of each battery SOC so that the battery can obtain a reasonable output power control method, such as Figure 6 As shown, at this time, all three batteries are in a deep discharge state. The photovoltaic panels charge the batteries. After the photovoltaic panels have finished charging the batteries, the batteries that have been disconnected from the deep discharge are reconnected, and the battery pack supplies power normally.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A dual-multiplexing, full-operation-condition topology self-switching island-supported energy router, characterized by: It includes a three-phase PWM rectifier unit, a three-phase PWM inverter unit, a bidirectional DC / DC conversion unit, a first bidirectional buck-boost conversion unit, a second bidirectional buck-boost conversion unit, and a third bidirectional buck-boost conversion unit; each port of the dual-multiplexed, full-operating-condition topology self-switching island-supported energy router is respectively connected to a generator, a photovoltaic panel, a battery pack, a supercapacitor, an AC load, and a DC load; the battery pack includes three batteries; The input end of the three-phase PWM rectifier unit is connected to the generator to obtain an AC power supply as an input power supply; the output end of the three-phase PWM rectifier unit is connected to the input end of the bidirectional DC / DC conversion unit; the output end of the three-phase PWM rectifier unit is also connected to the output end of the photovoltaic panel; the output end of the photovoltaic panel is connected to the battery pack; the output end of the bidirectional DC / DC conversion unit is connected to the input end of the three-phase PWM inverter unit; the output end of the three-phase PWM inverter unit is connected to the AC load; the input end of the first bidirectional BUCK-BOOST conversion unit, the input end of the second bidirectional BUCK-BOOST conversion unit, and the input end of the third bidirectional BUCK-BOOST conversion unit are all connected to the battery pack The output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, and the output end of the third bidirectional buck-boost conversion unit are all connected to the three-phase PWM inverter unit; the output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, and the output end of the third bidirectional buck-boost conversion unit are all connected to the output end of the supercapacitor; the output end of the first bidirectional buck-boost conversion unit, the output end of the second bidirectional buck-boost conversion unit, the output end of the third bidirectional buck-boost conversion unit, and the output end of the supercapacitor are all connected to a DC load; The island-supported energy router adjusts its operating mode based on the remaining capacity of the battery pack connected to the external port. It performs charging and discharging operations by determining the remaining capacity of the battery pack, and the remaining capacity can be dynamically adjusted between the batteries within the battery pack. The energy router can also control the output voltage of the photovoltaic panel connected to the external port by multiplexing the three-phase PWM rectifier unit, ensuring that the photovoltaic panel always maintains the maximum operating voltage.

2. The dual-multiplexing, full-operation-condition topology self-switching island-supported energy router according to claim 1 is characterized by: The method for calculating the remaining capacity of the battery pack is specifically as follows: (1) Based on the load index, energy utilization rate and anti-interference ability of the island-supported energy router, a dynamic remaining capacity calculation function f(t) of the battery pack with time t as the dependent variable is established, as shown in the following formula: Among them, K>0 is the index coefficient of the load borne by the energy router; α>0 is the energy utilization coefficient of the energy router; β>0 is the anti-interference ability coefficient of the energy router, p x (t), p y (t) are the total input power and total output power of the energy router at time t, as shown in the following formula: p x (t)=p1(t)+p2(t)p y (t)=p1(t)+p2(t)+p3(t) Among them, p1(t), p2(t), p3(t), p4(t), and p5(t) are the generator input power, photovoltaic panel port input power, AC load terminal output power, DC load terminal output power, and battery terminal output power at time t, respectively; T(t), T o ,、T * (t) and S1, respectively, are the ambient temperature, preset working ambient temperature, optimal working ambient temperature, and energy regulation coefficient of the island-supported energy router at time t; (2) Establishing optimization conditions for the dynamic remaining capacity calculation function f(t) of the battery pack, solving the three index functions f1(p1, p2), energy utilization function f2(p1, p2, p3, p4, p5), and anti-interference ability function f3(p5) of the load borne by the island support type energy router, and obtaining (p1, p2, p3, p4, p5), (p1, p2, p3, p4, p5) (2) ,(p1,p2,p3,p4,p5) (3) The single indicator under three sets of constraints is optimal; (3) According to the optimal single indicator under the three sets of constraints, the maximum value M of the optimal solution corresponding to each indicator is obtained i And the minimum value m in the optimal solution corresponding to each indicator i , determine the weighted coefficient of each indicator in, (4) Further construct the linear programming problem L(1) based on the sum μ of load index, energy utilization rate and anti-interference ability: Where R represents a real number; By solving the linear programming problem L(1), we can get the ideal solution of (p1, p2, p3, p4, p5), and bring the ideal solution into the three indicator functions for comparison. If the deviation of each indicator is less than the set threshold of 3%, then the M corresponding to the required indicator will be replaced. i Increase by 3%; if the deviation of each indicator is greater than the set threshold of 3%, the M corresponding to the required indicator will be increased. i Reduce by 3%, and restructure the planning problem L(2) again, as shown in the following formula: Then solve the linear programming problem L(2), repeatedly compare whether the deviation of each indicator satisfies the deviation less than the set threshold of 3%. If not, repeat until a set of actual ideal solutions (p1, p2, p3, p4, p5) is output, and substitute it into the dynamic remaining capacity calculation function of the battery pack f(t), which is the current dynamic remaining capacity calculation function of the battery pack; then judge the remaining capacity of the battery pack. If the remaining capacity of each battery is greater than or equal to 95% of the rated capacity, the battery supplies power to the outside; if the remaining capacity of each battery is less than 95% of the rated capacity, the photovoltaic panel charges the battery.

3. The dual-multiplexing, full-operation-condition topology self-switching island-supported energy router according to claim 1 is characterized by: The multiplexing of the three-phase PWM rectifier unit, that is, controlling the photovoltaic panels connected to the external ports of the three-phase PWM rectifier unit, is specifically performed as follows: The photovoltaic panel supplies power to the battery pack, and the output of the photovoltaic panel is connected to the battery pack. At the same time, the battery pack is disconnected from the input of the first bidirectional buck-boost conversion unit, the input of the second bidirectional buck-boost conversion unit, and the input of the third bidirectional buck-boost conversion unit. The remaining working units remain unchanged. Then, the MPPT algorithm is used to continuously collect the voltage and current of the photovoltaic panel output three times at a certain moment, and the output power of the photovoltaic panel is calculated based on the three collected voltage and current values. The tracking direction of the photovoltaic panel output voltage is determined by judging the change trend of the three photovoltaic panel output power; the value of the working voltage at the maximum output power of the predicted photovoltaic panel is used as the voltage reference value of the output end of the three-phase PWM rectifier unit, and substituted into the voltage reference value and actual voltage comparison link in the voltage outer loop of the voltage and current double closed loop during the rectification process of the three-phase PWM rectifier unit to control the voltage of the output end of the three-phase PWM rectifier unit, so that the output end voltage of the three-phase PWM rectifier unit changes towards the reference voltage.

4. The dual-multiplexing, full-operation-condition topology self-switching island-supported energy router according to claim 1 is characterized by: The island support type energy router selects different working modes according to the remaining capacity of the battery pack. The specific method is as follows: the external load power connected to the battery pack is set to P1, and the rated output power of a single bidirectional BUCK-BOOST conversion unit is P v , the battery pack and supercapacitor supply power to the load. At this time, the working status of the battery pack includes the following situations:

1. Determine whether the rated output power of a single bidirectional BUCK-BOOST conversion unit can meet the external load power connected to the battery pack. If the external load power P1 is less than or equal to the rated output power P of the bidirectional BUCK-BOOST conversion unit, v , then the island support type energy router enters working mode 1: The photovoltaic panel is disconnected from the battery pack. The batteries in the battery pack operate in series, and power is supplied to the load via the first bidirectional buck-boost converter. The output of the first bidirectional buck-boost converter is connected to the output of the supercapacitor. The second and third bidirectional buck-boost converters do not supply power to the load.

2. Determine whether the rated output power of the two bidirectional BUCK-BOOST conversion units can meet the external load power connected to the battery pack. If the external load power P1 is less than or equal to twice the rated output power 2P of the bidirectional BUCK-BOOST conversion unit, v , then the island support type energy router enters working mode 2: The photovoltaic panel is disconnected from the battery pack. Two batteries 2 and 3 in the battery pack are connected in series and then pass through the second bidirectional buck-boost converter unit. The other battery 1 passes through the first bidirectional buck-boost converter unit to supply power to the load. The output terminals of the first and second bidirectional buck-boost converter units are connected to the output terminal of the supercapacitor. Meanwhile, the third bidirectional buck-boost converter unit does not participate in supplying power to the load.

3. Determine whether the rated output power of the three bidirectional buck-boost converter units is not greater than three times the rated output power (3P) of the bidirectional buck-boost converter units. v , if it meets the requirements, the island support type energy router enters working mode 3: The photovoltaic panel is disconnected from the battery pack. First battery 1 is connected to the first bidirectional buck-boost conversion unit, second battery 2 is connected to the second bidirectional buck-boost conversion unit, and third battery 3 is connected to the third bidirectional buck-boost conversion unit. The output ends of the first, second, and third bidirectional buck-boost conversion units are connected in parallel to supply power to the load. To ensure the stability of power supply to the load, the output ends of the first, second, and third bidirectional buck-boost conversion units are connected to the output end of the supercapacitor.

5. The dual-multiplexing, full-operation-condition topology self-switching island-supported energy router according to claim 1 is characterized by: The method for adjusting the remaining capacity of the battery pack connected to the external port of the energy router is as follows: The remaining capacity of each battery in the battery pack is determined. If the remaining capacity of each battery is greater than or equal to the set rated capacity, the battery pack enters operating mode A; if the remaining capacity of any battery is less than the set rated capacity, the battery pack enters operating mode B.

6. The dual-multiplexing, full-operation-condition topology self-switching island-supported energy router according to claim 5 is characterized by: The battery pack enters working mode A specifically as follows: Monitor the dynamic remaining capacity of each battery and calculate the average SOC value of the battery pack port Define the imbalance degree of SOC of the k-port of the battery pack as ΔSOC (k) , define the output power target value of each port of the battery pack and current reference value I (k)-ref Based on the average power of each port of the battery pack, the power deviation is adjusted according to the SOC imbalance of the battery pack to obtain the battery pack port current reference value I (k)-ref And the real-time power transmission value P of the battery pack port (k)-ref , as shown below: Among them, V (k) is the output voltage value of the battery pack k port, is the target output power value of the battery group port, K a is the proportionality coefficient; The output power of the batteries is controlled again so that the SOC values ​​of the batteries remain equal.

7. The dual-multiplexing, full-operation-condition topology self-switching island-supported energy router according to claim 6 is characterized by: The battery pack enters working mode B specifically as follows: At this time, there is a battery in a deep discharge state. Disconnect the battery from the external load to wait for charging. Determine the number of batteries that can work normally, n, n < 3, and define the imbalance of each battery SOC as ε i , set the imbalance threshold ε m , construct the SOC imbalance diagonal matrix A of the battery pack as shown below: The elements ε in the diagonal matrix A are i The absolute value of ε m Compare, if A does not exist |ε i |>ε m elements, then the SOC of each battery remains balanced and the battery pack maintains its current output power unchanged; if there is |ε in A i |>ε m The elements of , calculated based on ε i Battery power distribution mode P i , get the diagonal matrix P of the power distribution mode of the battery pack refi , as shown in the following formula: Among them, K α Represents the temperature influence coefficient of the battery; As the battery pack operates, the value of A is constantly updated, and the maximum value of the imbalance degree of each battery ε MAX The balanced state of the SOC of each battery is determined so that the battery can obtain a reasonable output power control method. After the photovoltaic panel has completed charging the battery, the deeply discharged battery is reconnected and the battery pack can supply power normally.

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