Self-adaptive virtual inertia control circuit based on response characteristics of flow battery

Abstract

The invention discloses a self-adaptive virtual inertia control circuit based on flow battery response characteristics, and belongs to the technical field of power electronic converter control, the control circuit comprises a power grid voltage sampling circuit, an inductive current sampling circuit, a bus voltage sampling circuit and a digital control unit; the digital control unit comprises an abc / dq converter, a dq / abc converter, a d-axis voltage PI regulator, a q-axis voltage PI regulator, a bus voltage PI regulator, an SPWM controller, a PWM controller, a power calculator, a subtracter, a multiplier, a divider, an integrator, a proportioner, a damper, an inertia device, a flow cell flow regulation factor calculator and a flow cell charge state correction factor calculator. The invention discloses a flow battery temperature compensation factor calculator. According to the control circuit, the dynamic response characteristic of the flow battery is fully considered, and the anti-interference capability of the network-forming converter can be improved.

Description

Technical Field

[0001] This invention belongs to the field of power electronic converter control technology, and specifically relates to an adaptive virtual inertia control circuit based on the response characteristics of a flow battery. Background Technology

[0002] With the increasing penetration rate of renewable energy, virtual inertia control of grid-connected converters has become a key technology for maintaining grid frequency stability. Currently, the mainstream virtual inertia control of grid-connected converters is mainly designed for fast-response energy storage media such as lithium-ion batteries. Its characteristics are not compatible with those of flow batteries, which have slow-response characteristics. The existing technical literature "Dou Yan, Wang Chuanyi, Chen Zihui, Wang Chen, Li Xin, Modeling and Research of Grid-connected Energy Storage Based on Vanadium Redox Flow Battery, Electrical Appliances and Energy Efficiency Management Technology, 2024, (11): 29-37" established a hybrid model of flow battery with multi-physics coupling. Based on this model, a virtual synchronous generator control strategy was designed to achieve stable control of the grid-connected converter. Existing technical literature, "Yang Shiwei, Li Baohong, Jiang Qin, Zhang Yingmin, Liu Tianqi, Peng Qiao, Frequency Regulation Strategy of Grid-Based Energy Storage Considering SOC in Wind-Solar-Hydrogen Production Systems, Smart Power, 2025, 53(05): 8-15," proposes adjusting the control parameters of the virtual synchronous generator (VRG) based on the state of charge (SOC) of the energy storage battery to improve the support capability of the grid-based inverter. However, the above method is based on the analysis and research of virtual inertia control strategy of the grid-based inverter itself, and does not consider the impact of the flow battery response characteristics on the virtual inertia control strategy of the grid-based inverter. Therefore, it is necessary to study an adaptive virtual inertia control circuit based on the response characteristics of the flow battery to improve the transient performance of grid-based inverters using flow battery energy storage under grid disturbances. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes an adaptive virtual inertia control circuit based on the response characteristics of flow batteries. This circuit can fully consider the impact of the dynamic characteristics of flow batteries on the virtual inertia control parameters of the converter, thereby improving the transient performance of grid-connected inverters using flow battery energy storage under grid disturbances.

[0004] Specifically, this invention is an adaptive virtual inertia control circuit based on the response characteristics of a flow battery. The adaptive virtual inertia control circuit includes a vanadium redox flow battery (1), a DC / DC module (2), a DC bus capacitor (3), a DC / AC module (4), a three-phase output filter inductor (5), a three-phase AC power grid (6), a DC / AC module control circuit (7), a flow battery equivalent inertia coefficient calculation circuit (8), and a DC / DC module control circuit (9). Among them, the all-vanadium redox flow battery (1) is used to provide DC power; The DC / DC module (2) has its power input terminal connected to the positive and negative output terminals of the vanadium redox flow battery (1) for buck-boost conversion. A DC bus capacitor (3) is connected to the output terminal of the DC / DC module (2) to stabilize the DC bus voltage. The DC / AC module (4) has its input terminal connected to the DC bus capacitor (3) and is used to convert the DC voltage output by the DC / DC module (2) into an AC voltage for grid connection. A three-phase output filter inductor (5) is connected to the output terminal of the DC / AC module (4) and is used to filter the output voltage of the DC / AC module (4). The DC / AC module control circuit (7) includes an inductor current sampling circuit (71) and a grid voltage sampling circuit (72) and other control circuits, which are used to collect the current and voltage signals at the connection between the three-phase output filter inductor (5) and the three-phase AC grid (6) and adjust and control the drive signal input to the DC / AC module (4). The flow battery equivalent inertia coefficient calculation circuit (8) has its input terminal connected to the signal output terminal of the vanadium redox flow battery (1) and is used to calculate and provide an adaptive virtual inertia coefficient for the DC / AC module control circuit (7). The DC / DC module control circuit (9) has its input terminals connected to both sides of the DC bus capacitor (3) and is used to adjust and control the drive signal of the DC / DC module (2). The equivalent inertia coefficient calculation circuit (8) of the flow battery dynamically adjusts the virtual inertia coefficient according to the response characteristics of the vanadium redox flow battery (1), and achieves adaptive virtual inertia adjustment through the coordinated control of the DC / AC module control circuit (7) and the DC / DC module control circuit (9).

[0005] The DC / AC module control circuit (7) includes an inductor current sampling circuit (71) and a grid voltage sampling circuit (72). The three input terminals of the grid voltage sampling circuit (72) are connected to the connection between the three-phase output filter inductor (5) and the three-phase AC grid (6). The three output terminals of the grid voltage sampling circuit (72) are connected to the first, second, and third input terminals of the first abc / dq converter (74). The fourth input terminal of the first abc / dq converter (74) is connected to the output terminal of the first integrator (719). θ The two outputs of the first abc / dq converter (74) are connected to the first and second inputs of the power calculator (711), and the third and fourth inputs of the power calculator (711) are connected to the two outputs of the second abc / dq converter (73). i d , iq The reactive power output terminal of the power calculator (711) Q Connected to the negative input terminal of the first subtractor (712), the reactive power reference value Q ref The voltage reference value is connected to the positive input terminal of the first subtractor (712); the output terminal of the first subtractor (712) is connected to the input terminal of the first proportionalizer (713), and the output terminal of the first proportionalizer (713) is connected to the negative input terminal of the second subtractor (714); E ref The positive input terminal of the second subtractor (714) is connected to the positive input terminal of the second subtractor (714), and the output terminal of the second subtractor (714) is connected to the positive input terminal of the second subtractor (714). E Connected back to the positive input of the sixth subtractor (76); the active power output of the power calculator (711). P Connected to the negative input terminal of the third subtractor (715), active power reference value P ref The output of the third subtractor (715) is connected to the positive input of the fourth subtractor (716), and the output of the damper (720) is connected to the negative input of the fourth subtractor (716). The output of the fourth subtractor (716) is connected to the input of the inertia unit (717), and the output of the inertia unit (717) is connected to the multiplication input of the divider (718). The division input of the divider (718) is connected to the output of the flow battery temperature compensation factor calculator (83) in the flow battery equivalent inertia coefficient calculation circuit (8). The output of the divider (718) is connected to... The input terminals of the first integrator (719) and the damper (720) are connected to each other. The output terminal of the first integrator (719) is connected to the fourth input terminal of the first abc / dq converter (74) and the fourth input terminal of the second abc / dq converter (73). The three input terminals of the inductor current sampling circuit (71) are connected to the connection between the three-phase output filter inductor (5) and the three-phase AC power grid (6). The three output terminals of the inductor current sampling circuit (71) are connected to the first, second, and third input terminals of the second abc / dq converter (73). One output terminal of the second abc / dq converter (73) is connected to the input terminal of the first integrator (719) and the input terminal of the damper (720). i q Connected to the negative input of the fifth subtractor (75) and the third input of the power calculator (711), and the other output of the second abc / dq converter (73). i d The negative input terminal of the sixth subtractor (76) and the fourth input terminal of the power calculator (711) are connected; the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtractor (75), the output terminal of the fifth subtractor (75) is connected to the input terminal of the q-axis voltage PI regulator (77), and the output terminal of the q-axis voltage PI regulator (77) is connected to the negative input terminal of the sixth subtractor (76) and the fourth input terminal of the power calculator (711); the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtractor (75), the output terminal of the fifth subtractor (75) is connected to the input terminal of the q-axis voltage PI regulator (77), and the output terminal of the q-axis voltage PI regulator (77) is connected to the negative input terminal of the power calculator (76); the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtract uq The output of the sixth subtractor (76) is connected to the first input terminal of the dq / abc converter (79); the output terminal of the sixth subtractor (76) is connected to the input terminal of the d-axis voltage PI regulator (78), and the output terminal of the d-axis voltage PI regulator (78) is connected to the first input terminal of the dq / abc converter (79). u d The three output terminals of the dq / abc converter (79) are connected to the second input terminal of the dq / abc converter (79), and the three output terminals of the dq / abc converter (79) are connected to the three input terminals of the SPWM controller (710). The three output terminals of the SPWM controller (710) form a three-phase modulated wave that is connected to the DC / AC module (4).

[0006] The flow battery equivalent inertia coefficient calculation circuit (8) includes an input terminal of the flow battery flow adjustment factor calculator (81) connected to the first output terminal of the vanadium redox flow battery (1), which is the nominal inertia coefficient. H 0 is connected to another input terminal of the flow battery flow rate adjustment factor calculator (81); the output terminal of the flow battery flow rate adjustment factor calculator (81) is connected to one input terminal of the flow battery state of charge correction factor calculator (82), the other input terminal of the flow battery state of charge correction factor calculator (82) is connected to the second output terminal of the vanadium redox flow battery (1); the output terminal of the flow battery state of charge correction factor calculator (82) is connected to one input terminal of the flow battery temperature compensation factor calculator (83), the other input terminal of the flow battery temperature compensation factor calculator (83) is connected to the third output terminal of the vanadium redox flow battery (1), and the output terminal of the flow battery temperature compensation factor calculator (83) is connected to the division input terminal of the first divider (718) in the DC / AC module control circuit (7).

[0007] The DC / DC module control circuit (9) includes a bus voltage sampling circuit (91) connected to both sides of the DC bus capacitor (3), and the output terminal of the bus voltage sampling circuit (91) connected to the negative input terminal of the seventh subtractor (92); the DC bus voltage reference value U bus_ref The output of the seventh subtractor (92) is connected to the positive input terminal of the bus voltage PI regulator (93), and the output of the bus voltage PI regulator (93) is connected to the input terminal of the PWM controller (94). The output of the PWM controller (94) generates the duty cycle and is connected to the DC / DC module (2).

[0008] Furthermore, the equivalent inertia coefficient of the flow battery H RF It is equal to the product of the nominal inertia coefficient and the flow rate adjustment factor, the state of charge correction factor, and the temperature compensation factor of the flow battery.

[0009] Furthermore, the flow rate adjustment factor of the flow battery satisfies an exponential relationship related to the current electrolyte flow rate, the rated flow rate, and the time constant of the flow battery.

[0010] Furthermore, the state of charge correction factor of the flow battery satisfies an exponential relationship related to the current state of charge of the flow battery, the threshold of the state of charge of the flow battery, and the slope coefficient of the state of charge of the flow battery.

[0011] Furthermore, the flow battery temperature compensation factor satisfies an exponential relationship related to the current temperature of the flow battery, the activation energy of the electrolyte, the gas constant, and the reference temperature.

[0012] Compared with existing technologies, the beneficial effects are: This invention is the first to simultaneously incorporate three dynamic parameters—electrolyte flow rate, state of charge (SOC), and temperature—into a virtual inertia regulation system. A flow rate adjustment factor reflects the dynamic response characteristics of the electrolyte circulation system in real time, a SOC correction factor accurately captures instantaneous changes in the battery's energy storage state, and a temperature compensation factor automatically corrects for the influence of temperature on electrolyte activity. Furthermore, a closed-loop collaborative mechanism between the DC / DC and DC / AC module control circuits is employed to achieve real-time data interaction between the flow battery equivalent inertia coefficient calculation circuit and the power conversion circuit.

[0013] Through simulation and experimental verification, the technical solution of the present invention can achieve the following under different operating conditions: the system response time after grid disturbance is shortened by 5%-10% (compared to the constant parameter control scheme); the transient frequency deviation is reduced by more than 15% (when the SOC is in the 30%-70% operating range); and the temperature adaptability is improved, maintaining control stability in the range of 10-45℃.

[0014] Therefore, in scenarios with a high proportion of renewable energy integration, the technical solution of this invention solves the inherent defect of traditional VSG control inertia parameters not considering the dynamic characteristics of flow batteries, overcomes the adjustment lag problem of fixed inertia parameters under variable battery flow conditions, and eliminates the accumulation of virtual inertia control errors caused by temperature changes. This invention provides the first adaptive virtual inertia control solution for grid-connected inverters specifically designed for the characteristics of flow batteries, and has significant application value in the construction of new power systems. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of an adaptive virtual inertia control system based on the characteristics of a flow battery according to the present invention. Figure 2 This is the output power waveform of the control circuit of the present invention when the power grid frequency dips due to the strong dynamic response characteristics of the flow battery. Figure 3This is the output power waveform of the control circuit of the present invention when the power grid frequency drops due to the weak dynamic response characteristics of the flow battery. Detailed Implementation

[0016] The following detailed description, in conjunction with the accompanying drawings, illustrates a specific implementation of an adaptive virtual inertia control circuit based on the response characteristics of a flow battery according to the present invention.

[0017] An adaptive virtual inertia control circuit based on the response characteristics of a flow battery, the control circuit as follows: Figure 1 As shown, the adaptive virtual inertia control circuit includes a vanadium redox flow battery (1), a DC / DC module (2), a DC bus capacitor (3), a DC / AC module (4), a three-phase output filter inductor (5), a three-phase AC power grid (6), a DC / AC module control circuit (7), a flow battery equivalent inertia coefficient calculation circuit (8), and a DC / DC module control circuit (9). Among them, the all-vanadium redox flow battery (1) is used to provide DC power; The DC / DC module (2) has its power input terminal connected to the positive and negative output terminals of the vanadium redox flow battery (1) for buck-boost conversion. A DC bus capacitor (3) is connected to the output terminal of the DC / DC module (2) to stabilize the DC bus voltage. The DC / AC module (4) has its input terminal connected to the DC bus capacitor (3) and is used to convert the DC voltage output by the DC / DC module (2) into an AC voltage for grid connection. A three-phase output filter inductor (5) is connected to the output terminal of the DC / AC module (4) and is used to filter the output voltage of the DC / AC module (4). The DC / AC module control circuit (7) includes an inductor current sampling circuit (71) and a grid voltage sampling circuit (72) and other control circuits, which are used to collect the current and voltage signals at the connection between the three-phase output filter inductor (5) and the three-phase AC grid (6) and adjust and control the drive signal input to the DC / AC module (4). The flow battery equivalent inertia coefficient calculation circuit (8) has its input terminal connected to the signal output terminal of the vanadium redox flow battery (1) and is used to calculate and provide an adaptive virtual inertia coefficient for the DC / AC module control circuit (7). The DC / DC module control circuit (9) has its input terminals connected to both sides of the DC bus capacitor (3) and is used to adjust and control the drive signal of the DC / DC module (2). The DC / AC module control circuit (7) includes three input terminals of the grid voltage sampling circuit (72) connected to the connection point between the three-phase output filter inductor (5) and the three-phase AC grid (6); three output terminals of the grid voltage sampling circuit (72) connected to the first, second, and third input terminals of the first abc / dq converter (74); and the fourth input terminal of the first abc / dq converter (74) connected to the output terminal of the first integrator (719). θ The two outputs of the first abc / dq converter (74) are connected to the first and second inputs of the power calculator (711), and the third and fourth inputs of the power calculator (711) are connected to the two outputs of the second abc / dq converter (73). i d , i q The reactive power output terminal of the power calculator (711) Q Connected to the negative input terminal of the first subtractor (712), the reactive power reference value Q ref The voltage reference value is connected to the positive input terminal of the first subtractor (712); the output terminal of the first subtractor (712) is connected to the input terminal of the first proportionalizer (713), and the output terminal of the first proportionalizer (713) is connected to the negative input terminal of the second subtractor (714); E ref The positive input terminal of the second subtractor (714) is connected to the positive input terminal of the second subtractor (714), and the output terminal of the second subtractor (714) is connected to the positive input terminal of the second subtractor (714). E Connected back to the positive input of the sixth subtractor (76); the active power output of the power calculator (711). P Connected to the negative input terminal of the third subtractor (715), active power reference value P refThe output of the third subtractor (715) is connected to the positive input of the fourth subtractor (716), and the output of the damper (720) is connected to the negative input of the fourth subtractor (716). The output of the fourth subtractor (716) is connected to the input of the inertia unit (717), and the output of the inertia unit (717) is connected to the multiplication input of the divider (718). The division input of the divider (718) is connected to the output of the flow battery temperature compensation factor calculator (83) in the flow battery equivalent inertia coefficient calculation circuit (8). The output of the divider (718) is connected to... The input terminals of the first integrator (719) and the damper (720) are connected to each other. The output terminal of the first integrator (719) is connected to the fourth input terminal of the first abc / dq converter (74) and the fourth input terminal of the second abc / dq converter (73). The three input terminals of the inductor current sampling circuit (71) are connected to the connection between the three-phase output filter inductor (5) and the three-phase AC power grid (6). The three output terminals of the inductor current sampling circuit (71) are connected to the first, second, and third input terminals of the second abc / dq converter (73). One output terminal of the second abc / dq converter (73) is connected to the input terminal of the first integrator (719) and the input terminal of the damper (720). i q Connected to the negative input of the fifth subtractor (75) and the third input of the power calculator (711), and the other output of the second abc / dq converter (73). i d The negative input terminal of the sixth subtractor (76) and the fourth input terminal of the power calculator (711) are connected; the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtractor (75), the output terminal of the fifth subtractor (75) is connected to the input terminal of the q-axis voltage PI regulator (77), and the output terminal of the q-axis voltage PI regulator (77) is connected to the negative input terminal of the sixth subtractor (76) and the fourth input terminal of the power calculator (711); the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtractor (75), the output terminal of the fifth subtractor (75) is connected to the input terminal of the q-axis voltage PI regulator (77), and the output terminal of the q-axis voltage PI regulator (77) is connected to the negative input terminal of the power calculator (76); the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtract u q The output of the sixth subtractor (76) is connected to the first input terminal of the dq / abc converter (79); the output terminal of the sixth subtractor (76) is connected to the input terminal of the d-axis voltage PI regulator (78), and the output terminal of the d-axis voltage PI regulator (78) is connected to the first input terminal of the dq / abc converter (79). u d The three output terminals of the dq / abc converter (79) are connected to the second input terminal of the dq / abc converter (79), and the three output terminals of the dq / abc converter (79) are connected to the three input terminals of the SPWM controller (710). The three output terminals of the SPWM controller (710) form a three-phase modulated wave that is connected to the DC / AC module (4).

[0018] The flow battery equivalent inertia coefficient calculation circuit (8) includes an input terminal of the flow battery flow adjustment factor calculator (81) connected to the first output terminal of the vanadium redox flow battery (1), which is the nominal inertia coefficient. H0 is connected to another input terminal of the flow battery flow rate adjustment factor calculator (81); the output terminal of the flow battery flow rate adjustment factor calculator (81) is connected to one input terminal of the flow battery state of charge correction factor calculator (82), the other input terminal of the flow battery state of charge correction factor calculator (82) is connected to the second output terminal of the vanadium redox flow battery (1); the output terminal of the flow battery state of charge correction factor calculator (82) is connected to one input terminal of the flow battery temperature compensation factor calculator (83), the other input terminal of the flow battery temperature compensation factor calculator (83) is connected to the third output terminal of the vanadium redox flow battery (1), and the output terminal of the flow battery temperature compensation factor calculator (83) is connected to the division input terminal of the first divider (718) in the DC / AC module control circuit (7).

[0019] The DC / DC module control circuit (9) includes a bus voltage sampling circuit (91) connected to both sides of the DC bus capacitor (3), and the output terminal of the bus voltage sampling circuit (91) connected to the negative input terminal of the seventh subtractor (92); the DC bus voltage reference value U bus_ref The output of the seventh subtractor (92) is connected to the positive input terminal of the bus voltage PI regulator (93), and the output of the bus voltage PI regulator (93) is connected to the input terminal of the PWM controller (94). The output of the PWM controller (94) generates the duty cycle and is connected to the DC / DC module (2).

[0020] The equivalent inertia coefficient of the flow battery is calculated by the circuit (8). H RF satisfy,

[0021] in H 0 is the nominal inertia coefficient. f Q ( Q ) is the flow rate regulation factor for flow batteries. f SOC ( SOC ) is the state-of-charge correction factor for flow batteries. f T ( T ) is the temperature compensation factor for flow batteries.

[0022] Flow battery flow rate adjustment factor calculator (81) f Q ( Q The expression satisfies,

[0023] in Q This represents the current electrolyte flow rate of the flow battery.Q 0 represents the rated flow rate of the flow battery. τ Q is the time constant of the flow cell.

[0024] Flow battery state of charge correction factor calculator f SOC ( SOC The expression satisfies,

[0025] in SOC This represents the current state of charge of the flow battery. SOC th This is the threshold value for the state of charge of a flow battery. k SOC This is the slope coefficient of the state of charge of the flow battery.

[0026] Flow battery temperature compensation factor calculator f T ( T The expression satisfies,

[0027] in T This is the current temperature of the flow battery. E a The activation energy of the electrolyte in a flow battery. R The gas constant of a flow cell is... T 0 represents the reference temperature for the flow battery.

[0028] Experimental verification: Figure 2 , Figure 3 When using the control circuit of this invention for a two-stage energy storage inverter, the simulated output power waveforms under the same grid disturbance are obtained for different flow battery dynamic response characteristics. It can be seen that the control circuit of this invention can further optimize the virtual inertia parameters according to different flow battery dynamic response characteristics, accelerate the system response speed under grid disturbance, and improve the transient performance of grid-connected inverters using flow battery energy storage under grid disturbance.

[0029] Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention and not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific embodiments of the present invention, but such modifications or alterations are all within the scope of protection of the pending claims.

Claims

1. An adaptive virtual inertia control circuit based on the response characteristics of a flow battery, characterized in that, include: Vanadium redox flow battery (1) for providing DC power; The DC / DC module (2) has its power input terminal connected to the positive and negative output terminals of the vanadium redox flow battery (1) for buck-boost conversion. A DC bus capacitor (3) is connected to the output terminal of the DC / DC module (2) to stabilize the DC bus voltage. The DC / AC module (4) has its input terminal connected to the DC bus capacitor (3) and is used to convert the DC voltage output by the DC / DC module (2) into an AC voltage for grid connection. A three-phase output filter inductor (5) is connected to the output terminal of the DC / AC module (4) and is used to filter the output voltage of the DC / AC module (4). The DC / AC module control circuit (7) includes an inductor current sampling circuit (71) and a grid voltage sampling circuit (72) and other control circuits, which are used to collect the current and voltage signals at the connection between the three-phase output filter inductor (5) and the three-phase AC grid (6) and adjust and control the drive signal input to the DC / AC module (4). The flow battery equivalent inertia coefficient calculation circuit (8) has its input terminal connected to the signal output terminal of the vanadium redox flow battery (1) and is used to calculate and provide an adaptive virtual inertia coefficient for the DC / AC module control circuit (7). The DC / DC module control circuit (9) has its input terminals connected to both sides of the DC bus capacitor (3) and is used to adjust and control the drive signal of the DC / DC module (2). The equivalent inertia coefficient calculation circuit (8) of the flow battery dynamically adjusts the virtual inertia coefficient according to the response characteristics of the vanadium redox flow battery (1), and achieves adaptive virtual inertia adjustment through the coordinated control of the DC / AC module control circuit (7) and the DC / DC module control circuit (9).

2. The adaptive virtual inertia control circuit based on the characteristics of a flow battery according to claim 1, characterized in that, The three output terminals of the grid voltage sampling circuit (72) are connected to the first, second, and third input terminals of the first abc / dq converter (74); the two output terminals of the first abc / dq converter (74) are connected to the first and second input terminals of the power calculator (711); and the third and fourth input terminals of the power calculator (711) are connected to the two output terminals of the second abc / dq converter (73). i d , i q The reactive power output terminal of the power calculator (711) Q Connected to the negative input terminal of the first subtractor (712), the reactive power reference value Q ref The voltage reference value is connected to the positive input terminal of the first subtractor (712); the output terminal of the first subtractor (712) is connected to the input terminal of the first proportionalizer (713), and the output terminal of the first proportionalizer (713) is connected to the negative input terminal of the second subtractor (714); E ref The positive input terminal of the second subtractor (714) is connected to the positive input terminal of the second subtractor (714), and the output terminal of the second subtractor (714) is connected to the positive input terminal of the second subtractor (714). E Connect back to the positive input of the sixth subtractor (76).

3. The adaptive virtual inertia control circuit based on the stress characteristics of a flow battery according to claim 2, characterized in that, The active power output terminal of the power calculator (711) P Connected to the negative input terminal of the third subtractor (715), active power reference value P ref The output of the third subtractor (715) is connected to the positive input of the fourth subtractor (716), and the output of the damper (720) is connected to the negative input of the fourth subtractor (716). The output of the fourth subtractor (716) is connected to the input of the inertial device (717), and the output of the inertial device (717) is connected to the multiplication input of the divider (718). The division input of the divider (718) is connected to the flow battery temperature compensation factor calculation circuit (8) in the flow battery equivalent inertia coefficient calculation circuit. The output terminal of the divider (718) is connected to the input terminal of the first integrator (719) and the input terminal of the damper (720). The output terminal of the first integrator (719) is connected to the fourth input terminal of the first abc / dq converter (74) and the fourth input terminal of the second abc / dq converter (73). The three output terminals of the inductor current sampling circuit (71) are connected to the first, second, and third input terminals of the second abc / dq converter (73). One output terminal of the second abc / dq converter (73) is connected to the output terminal of the second abc / dq converter (73). i q The other output of the second abc / dq converter (73) is connected to the negative input of the fifth subtractor (75). i d The negative input terminal of the sixth subtractor (76) is connected to the negative input terminal; the q-axis current reference value 0 is connected to the positive input terminal of the fifth subtractor (75), the output terminal of the fifth subtractor (75) is connected to the input terminal of the q-axis voltage PI regulator (77), and the output terminal of the q-axis voltage PI regulator (77) is connected to the negative input terminal of the sixth subtractor (76); ... u q The output of the sixth subtractor (76) is connected to the first input terminal of the dq / abc converter (79); the output terminal of the sixth subtractor (76) is connected to the input terminal of the d-axis voltage PI regulator (78), and the output terminal of the d-axis voltage PI regulator (78) is connected to the first input terminal of the dq / abc converter (79). u d The three output terminals of the dq / abc converter (79) are connected to the second input terminal of the dq / abc converter (79), and the three output terminals of the dq / abc converter (79) are connected to the three input terminals of the SPWM controller (710). The three output terminals of the SPWM controller (710) form a three-phase modulated wave that is connected to the DC / AC module (4).

4. The adaptive virtual inertia control circuit based on the stress characteristics of a flow battery according to claim 3, characterized in that, One input terminal of the flow battery flow rate adjustment factor calculator (81) of the flow battery equivalent inertia coefficient calculation circuit (8) is connected to the first output terminal of the vanadium redox flow battery (1), and the nominal inertia coefficient is calculated. H 0 is connected to another input terminal of the flow battery flow rate adjustment factor calculator (81); the output terminal of the flow battery flow rate adjustment factor calculator (81) is connected to one input terminal of the flow battery state of charge correction factor calculator (82), the other input terminal of the flow battery state of charge correction factor calculator (82) is connected to the second output terminal of the vanadium redox flow battery (1); the output terminal of the flow battery state of charge correction factor calculator (82) is connected to one input terminal of the flow battery temperature compensation factor calculator (83), the other input terminal of the flow battery temperature compensation factor calculator (83) is connected to the third output terminal of the vanadium redox flow battery (1), and the output terminal of the flow battery temperature compensation factor calculator (83) is connected to the division input terminal of the first divider (718) in the DC / AC module control circuit (7).

5. The adaptive virtual inertia control circuit based on the stress characteristics of a flow battery according to claim 3, characterized in that, One input terminal of the flow battery flow rate adjustment factor calculator (81) of the flow battery equivalent inertia coefficient calculation circuit (8) is connected to the first output terminal of the vanadium redox flow battery (1), and the nominal inertia coefficient is calculated. H 0 is connected to another input terminal of the flow battery flow rate adjustment factor calculator (81); the output terminal of the flow battery flow rate adjustment factor calculator (81) is connected to one input terminal of the flow battery state of charge correction factor calculator (82), the other input terminal of the flow battery state of charge correction factor calculator (82) is connected to the second output terminal of the vanadium redox flow battery (1); the output terminal of the flow battery state of charge correction factor calculator (82) is connected to one input terminal of the flow battery temperature compensation factor calculator (83), the other input terminal of the flow battery temperature compensation factor calculator (83) is connected to the third output terminal of the vanadium redox flow battery (1), and the output terminal of the flow battery temperature compensation factor calculator (83) is connected to the division input terminal of the first divider (718) in the DC / AC module control circuit (7).

6. The adaptive virtual inertia control circuit based on the stress characteristics of a flow battery according to claim 4, characterized in that, The equivalent inertia coefficient of the flow battery H RF satisfy: ; in H 0 is the nominal inertia coefficient. f Q ( Q ) is the flow rate regulation factor for flow batteries. f SOC ( SOC ) is the state-of-charge correction factor for flow batteries. f T ( T ) is the temperature compensation factor for flow batteries.

7. The adaptive virtual inertia control circuit based on the stress characteristics of a flow battery according to claim 4, characterized in that, The flow battery flow regulation factor f Q ( Q The expression satisfies: ; in Q This represents the current electrolyte flow rate of the flow battery. Q 0 represents the rated flow rate of the flow battery. τ Q is the time constant of the flow cell.

8. The adaptive virtual inertia control circuit based on the characteristics of a flow battery according to claim 4, characterized in that, The flow battery state of charge correction factor f SOC ( SOC The expression satisfies: ; Wherein SOC is the current state of charge of the flow battery, SOC th is the threshold of the state of charge of the flow battery, k SOC is the slope coefficient of the state of charge of the flow battery.

9. The adaptive virtual inertia control circuit based on the stress characteristics of a flow battery according to claim 4, characterized in that, The flow battery temperature compensation factor f T ( T The expression satisfies: ; in T This is the current temperature of the flow battery. E a The activation energy of the electrolyte in a flow battery. R The gas constant of a flow cell is... T 0 represents the reference temperature for the flow battery.

Images