Power allocation method for multi-port photovoltaic-storage hybrid power generation system based on vector decomposition

Abstract

The present invention discloses a power distribution method for a multi-port photovoltaic storage hybrid power generation system based on vector decomposition, which equivalently models a multi-port inverter as two two-level inverters, decomposes the reference voltage vector of the multi-port inverter into two independent parts corresponding to the reference voltage vector of the two-level inverter according to control parameters, and uses a vector decomposition modulation method for the two two-level inverters to obtain the duty cycle of the upper inverter and the lower inverter. After obtaining the switching sequence of the two inverters, the switching sequence of the multi-port inverter can be constructed by superimposing the switching sequences of the two two-level inverters. Since the two two-level inverters are equivalently modeled, the decoupling control of the port power is realized, so flexible power distribution can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic-storage hybrid power generation systems, and more specifically, relates to a power distribution method for a multi-port photovoltaic-storage hybrid power generation system based on vector decomposition. Background Art

[0002] Photovoltaic power generation technology plays an important role in solving the challenges of fossil energy shortage and environmental pollution. Energy storage devices are usually integrated into photovoltaic power generation systems to improve power quality and smooth power fluctuations. Compared with traditional multi-stage photovoltaic storage hybrid power generation systems, single-stage multi-port inverters directly connect photovoltaic units and energy storage devices to the AC side, with higher system efficiency and power density.

[0003] However, due to the intermittent and unstable nature of photovoltaic power generation and the changing state of charge of energy storage devices, unbalanced DC port voltages are inevitable in multi-port inverter systems, which poses a challenge to the modulation design of multi-port inverters. Therefore, the traditional modulation strategy of multi-level converters under balanced port voltages cannot be applied in multi-port inverters.

[0004] In order to solve the problem of unbalanced port voltage and realize flexible power allocation of multi-port inverter systems, the existing power allocation strategy adopts a solution of adjusting redundant small vectors during the modulation process. However, the freedom of adjusting redundant small vectors is limited, so the scope of power allocation is limited. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a power allocation method for a multi-port photovoltaic storage hybrid power generation system based on vector decomposition. The multi-port inverter is equivalently modeled as two two-level inverters, and the reference voltage vector is also proportionally decomposed into the voltage vectors of two equivalent two-level inverters, thereby realizing decoupling control of the DC port power.

[0006] To achieve the above-mentioned object of the invention, the present invention provides a power allocation method for a multi-port photovoltaic storage hybrid power generation system based on vector decomposition, which is characterized by comprising the following steps:

[0007] (1) Calculate the active power of the two DC ports of the multi-port photovoltaic storage hybrid power generation system, that is, the active power output of the high-voltage port and the low-voltage port;

[0008]

[0009] Among them, P1 and P2 are the active power of the high-voltage port and the low-voltage port respectively, V1 and V2 are the voltages across the DC bus voltage stabilizing capacitors C1 and C2 respectively, and V H 、V L Represent the voltage of the high voltage port and the low voltage port respectively, i xis the three-phase current output by the multi-port inverter, D xu , D xl They represent the switching signals S of the first switch tube and the second switch tube in the x-phase bridge arm of the multi-port inverter respectively. x1 , S x2 Duty cycle, x = a, b, c represents three phases;

[0010] (2) According to the power management strategy of the multi-port photovoltaic storage hybrid power generation system, the energy management module gives the reference power P of the high-voltage port 1ref , then P 1ref Subtract it from P1, and the difference is passed through the power PI controller to obtain the control parameter ξ;

[0011] (3) Set the multi-port inverter in the multi-port photovoltaic storage hybrid power generation system to operate in island mode, and obtain the reference voltage vector u on the multi-port inverter side. ref ;

[0012] (3.1), given the three-phase reference voltage u that is expected to be obtained on the load side of the multi-port photovoltaic and energy storage hybrid power generation system x-ref ;

[0013] (3.2), the three-phase reference voltage u x-ref After T1 coordinate transformation, the reference voltage u in the dq coordinate system output by the multi-port inverter in island mode is obtained. d-ref 、u q-ref ;

[0014] The voltage u output by the three-phase voltage detector in the multi-port photovoltaic storage hybrid power generation system g After T1 coordinate transformation, the voltage u of the dq axis is obtained d 、u q ; The current I output by the three-phase current detector g After T1 coordinate transformation, the current I in the dq coordinate system is obtained d ,I q ;

[0015] (3.3), will u d-ref and u d The difference is then passed through the d-axis voltage PI controller to obtain the d-axis current

[0016] Will and I d The difference is then passed through the d-axis current PI controller to obtain the d-axis voltage Then with u d-ref Sum and get the final output voltage of the d-axis

[0017] (3.4),u q-ref and u q The difference is then passed through the q-axis voltage PI controller to obtain the q-axis current

[0018] Will and I q The difference is then passed through the q-axis current PI controller to obtain the q-axis voltage Then with u q-ref Sum and get the final output voltage of the q axis

[0019] (3.5) The final output voltage of the dq axis Through T2 coordinate transformation, the voltage value u of the multi-port inverter in the αβ coordinate system is obtained α-ref 、u β-ref ;

[0020] (3.6), the voltage value u α-ref 、u β-ref Through T3 coordinate transformation, the reference voltage vector u on the multi-port inverter side is obtained ref ;

[0021] (4) Equivalent modeling and vector allocation of multi-port inverters;

[0022] The multi-port inverter is equivalently modeled as two upper and lower two-level inverters, where the DC link voltage of the upper inverter is V1, and the DC link voltage of the lower inverter is V2; the equivalent switch tube of the upper inverter is S x1 , S x3 , the equivalent switch tube of the lower inverter is denoted as S x2 , S x4 ; S x1 , S x2 , S x3 , S x4 They respectively represent the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube in the x-th phase bridge arm of the multi-port inverter;

[0023] The multi-port inverter uses the reference voltage vector u ref According to the proportional coefficient ξ, it is respectively distributed to the upper and lower inverters, where the reference voltage vector allocated to the lower inverter is ξu ref , the reference voltage vector allocated to the upper inverter is (1-ξ)u ref ;

[0024] (5) In two-level space vector modulation, the space voltage vector is divided into the following six sectors according to the phase θ:

[0025]

[0026] (6) Generate a switching signal for driving a multi-port inverter based on a modulation method based on vector decomposition;

[0027] (6.1), construct the expression of the residence time corresponding to two adjacent non-zero vectors and the zero vector in each sector:

[0028] T S u ref =T1u k1 +T2u k2 +T0u k0

[0029] T S =T1+T2+T0

[0030] Among them, T s is the switching period, u k1 、u k2 、u k0 Two adjacent non-zero vectors and a zero vector that make up the kth sector, k = 1, 2, 3, 4, 5, 6 represents 6 sector numbers; T1, T2, T0 are the residence times corresponding to each vector;

[0031] (6.2), according to the reference voltage vector ξu of the lower inverter ref and the reference voltage vector (1-ξ)u of the upper inverter ref , respectively determine which sector the phase of each reference voltage vector falls in, and then calculate the residence time corresponding to each vector based on the formula in step S6.1, where the residence time of the lower inverter is recorded as T Lz , the residence time of the upper inverter is recorded as T Uz , z=0,1,2 represents two adjacent non-zero vectors and a zero vector;

[0032] (6.3) Calculate the duty cycle of each phase of the upper inverter and the lower inverter based on the classic PWM strategy;

[0033]

[0034] Among them, d xu is the duty cycle of each phase of the upper inverter, d xl is the duty cycle of each phase of the lower inverter;

[0035] (6.4) Generate the modulation waveform SVPWM through the duty cycle of each phase of the upper and lower inverters 上 With SVPWM 下 Then, the modulation waveform is compared with the amplitude of the triangular carrier in one switching cycle to generate six switching signals G that drive the multi-port inverter. x1 , G x2 ;

[0036] (7) Controlling the switching actions of the three bridge arms of the multi-port inverter through a switching signal;

[0037] The switch signal G x1 , G x2 Acting on the three bridge arms of the multi-port inverter, using the drive signal G x1 Control switch tube S x1 , driving signal G x1 The complementary signal controls the switch tube S x3 , driving signal G x2 Control switch tube S x2 , driving signal G x2 The complementary signal controls the switch tube S x4 , thereby controlling the switching tubes on each bridge arm to perform switching actions.

[0038] The object of the invention of the present invention is achieved in this way:

[0039] The present invention is based on a power allocation method for a multi-port photovoltaic storage hybrid power generation system based on vector decomposition, which equivalently models a multi-port inverter as two two-level inverters, decomposes the reference voltage vector of the multi-port inverter into two independent parts corresponding to the reference voltage vector of the two-level inverter according to control parameters, and uses a vector decomposition modulation method for the two two-level inverters to obtain the duty cycle of the upper inverter and the lower inverter. After obtaining the switching sequence of the two inverters, the switching sequence of the multi-port inverter can be constructed by superimposing the switching sequences of the two two-level inverters. Since the two two-level inverters are equivalently modeled, the decoupling control of the port power is realized, so flexible power allocation can be achieved.

[0040] At the same time, the power allocation method of the multi-port photovoltaic storage hybrid power generation system based on vector decomposition of the present invention also has the following beneficial effects:

[0041] (1) In order to achieve flexible power control under the condition of port voltage imbalance, the present invention proposes a decoupling model. The modeling method models the medium-scale integrated circuit as two two-level inverters, and decomposes the reference voltage vector into two independent parts according to the vector decomposition method to generate the reference voltage vector of the two two-level inverters. This can not only avoid the complex modulation problem caused by the imbalance of the DC link, but also achieve decoupling control, and the port power can be controlled independently.

[0042] (2) Due to the intermittent and unstable nature of photovoltaic power generation, it is necessary to collect more energy generated by renewable energy. The present invention increases the freedom of power allocation by decomposing the voltage vector output by the decoupling model, and effectively solves the technical problem of the limited power allocation range in the existing power allocation method.

[0043] (3) Replacing the existing two-stage topology with a multi-port inverter improves the efficiency of the entire system, increases the power density and energy transmission efficiency in the system, and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a structural diagram of a photovoltaic-storage hybrid power generation system based on multi-port inverter connection;

[0045] Figure 2 It is the equivalent decoupling model of the multi-port inverter;

[0046] Figure 3 It is a power distribution control block diagram of a multi-port photovoltaic storage hybrid power generation system based on vector decomposition of the present invention;

[0047] Figure 4 It is a switch action diagram of a multi-port photovoltaic storage hybrid power generation system power allocation method based on vector decomposition under three different port voltages V1=V2, V1>V2 and V1<V2;

[0048] Figure 5 It is the steady-state performance of the power allocation method of a multi-port photovoltaic-storage hybrid power generation system based on vector decomposition under three different port voltages V1=V2, V1>V2 and V1<V2;

[0049] Figure 6 It is the power allocation range of the multi-port photovoltaic storage hybrid power generation system power allocation method based on vector decomposition under different port voltage ratios. DETAILED DESCRIPTION

[0050] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0051] Example

[0052] Figure 1 This is the structural diagram of the photovoltaic storage hybrid power generation system based on multi-port inverter connection.

[0053] In this embodiment, we first briefly introduce the multi-port photovoltaic storage hybrid power generation system based on vector decomposition. Figure 1 As shown, it includes: a DC bus voltage stabilizing capacitor C11, a DC bus voltage stabilizing capacitor C22, a diode 3, a multi-port current inverter 4, and an LC filter 5.

[0054] like Figure 2As shown, the left figure is a multi-port inverter structure diagram, which has two input terminals and one output terminal; the multi-port inverter structure is improved from the diode clamped (NPC) three-level inverter topology, with a power supply connected to the positive and negative poles, and another power supply connected between the neutral line and the ground line. A capacitor is connected between the neutral line and the ground line, and another capacitor is connected between the neutral line and the positive pole, while retaining the original three bridge arms of the inverter.

[0055] The right figure shows the upper and lower two-level inverters after equivalent modeling of the multi-port inverter. The DC port voltage of the upper inverter is V1, the DC port voltage of the lower inverter is V2, and the equivalent switch tube of the upper inverter is S x1 , S x3 ; The equivalent switch tube of the lower inverter is selected as S x2 , S x4 ;

[0056] Next we combine Figure 3 , the power allocation strategy of the multi-port photovoltaic storage hybrid power generation system based on vector decomposition is described. The specific allocation includes the following steps:

[0057] S1. Calculate the active power of two DC ports of the multi-port photovoltaic storage hybrid power generation system, that is, the active power output by the high-voltage port and the low-voltage port;

[0058]

[0059] Among them, P1 and P2 are the active power of the high-voltage port and the low-voltage port respectively, V1 and V2 are the voltages across the DC-side stabilizing capacitors C1 and C2 respectively, and V H 、V L Represent the voltage of the high voltage port and the low voltage port respectively, i x is the three-phase current output by the multi-port inverter, D xu , D xl They represent the switching signals S of the first switch tube and the second switch tube in the x-phase bridge arm of the multi-port inverter respectively. x1 , S x2 Duty cycle, x = a, b, c represents three phases;

[0060] S2. According to the power management strategy of the photovoltaic storage hybrid power generation system, the energy management module gives the reference power P of the high-voltage port 1ref , then P 1ref The difference is obtained by the power PI controller to obtain the control parameter ξ. To avoid over-modulation, the control parameter must satisfy:

[0061]

[0062] S3, set the multi-port inverter in the multi-port photovoltaic storage hybrid power generation system to operate in the island mode, and obtain the reference voltage vector u on the multi-port inverter side ref ;

[0063] S3.1, given the three-phase reference voltage u expected to be obtained on the load side of the multi-port photovoltaic storage hybrid power generation system x-ref ;

[0064] S3.2, the three-phase reference voltage u x-ref After T1 coordinate transformation, the reference voltage u in the dq coordinate system output by the multi-port inverter in island mode is obtained. d-ref 、u q-ref ;

[0065] The voltage u output by the three-phase voltage detector in the multi-port photovoltaic storage hybrid power generation system g After T1 coordinate transformation, the voltage u of the dq axis is obtained d 、u q ; The current I output by the three-phase current detector g After T1 coordinate transformation, the current I in the dq coordinate system is obtained d ,I q ;

[0066] S3.3, in the second difference operation unit, u d-ref and u d The difference is then passed through the d-axis voltage PI controller to obtain the d-axis current

[0067] In the fourth difference operation unit, and I d The difference is then passed through the d-axis current PI controller to obtain the d-axis voltage Then in the second sum operation unit, with u d-ref Sum and get the final output voltage of the d-axis

[0068] S3.4, in the first difference operation unit, u q-ref and u q The difference is then passed through the q-axis voltage PI controller to obtain the q-axis current

[0069] In the third difference operation unit, and I q The difference is then passed through the q-axis current PI controller to obtain the q-axis voltage Then in the first sum operation unit, with u q-ref Sum and get the final output voltage of the q axis

[0070] S3.5, the final output voltage of the dq axis Through T2 coordinate transformation, the voltage value u of the multi-port inverter in the αβ coordinate system is obtained α-ref 、u β-ref ;

[0071] S3.6, set the voltage value u α-ref 、u β-ref Through T3 coordinate transformation, the reference voltage vector u on the multi-port inverter side is obtained ref ;

[0072] S4. The multi-port inverter is equivalently modeled as two upper and lower two-level inverters, where the DC link voltage of the upper inverter is V1 and the DC link voltage of the lower inverter is V2; the equivalent switch tube of the upper inverter is S x1 , S x3 , the equivalent switch tube of the lower inverter is denoted as S x2 , S x4 ; S x1 , S x2 , S x3 , S x4 They respectively represent the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube in the x-th phase bridge arm of the multi-port inverter;

[0073] In this embodiment, the multi-port inverter converts the reference voltage u ref According to the proportional coefficient ξ, it is respectively distributed to the upper and lower inverters, where the reference voltage vector allocated to the lower inverter is ξu ref , the reference voltage vector allocated to the upper inverter is (1-ξ)u ref ;

[0074] The multi-port inverter shares the same current with the upper inverter and the lower inverter, so it can be concluded that the active power of the upper inverter and the lower inverter is proportional to the voltage vector, so the active power of the upper inverter and the lower inverter can also be determined by ξ

[0075]

[0076] Among them, P U is the active power of the upper inverter, P L is the active power of the lower inverter, P ref is the reference active power expected on the load side;

[0077] There is a relationship between the high-voltage port power and low-voltage port power of the multi-port inverter and the power of the upper and lower inverters, so the active power of the high-voltage port voltage can also be determined by ξ:

[0078]

[0079] Therefore, flexible power control of the DC port of the multi-port inverter can be achieved by adjusting the control parameters;

[0080] S5. In two-level space vector modulation, the space voltage vector is divided into the following six sectors according to the phase θ:

[0081]

[0082] S6, generating a switching signal for driving a multi-port inverter based on a modulation method of vector decomposition;

[0083] S6.1. Construct an expression for the residence time corresponding to two adjacent non-zero vectors and a zero vector in each sector:

[0084] T S u ref =T1u k1 +T2u k2 +T0u k0

[0085] T S =T1+T2+T0

[0086] Among them, T s is the switching period, u k1 、u k2 、u k0 Two adjacent non-zero vectors and a zero vector that make up the kth sector, k = 1, 2, 3, 4, 5, 6 represents 6 sector numbers; T1, T2, T0 are the residence times corresponding to each vector;

[0087] S6.2, according to the reference voltage vector ξu of the lower inverter ref and the reference voltage vector (1-ξ)u of the upper inverter ref , respectively determine which sector each reference voltage vector falls in, and then calculate the residence time corresponding to each vector based on the formula in step S6.1, where the residence time of the lower inverter is recorded as T Lz , the residence time of the upper inverter is recorded as T Uz , z=0,1,2 represents two adjacent non-zero vectors and a zero vector;

[0088] S6.3, calculating the duty cycle of each phase of the upper inverter and the lower inverter based on the classic PWM strategy;

[0089]

[0090] Among them, d xu is the duty cycle of each phase of the upper inverter, d xl is the duty cycle of each phase of the lower inverter;

[0091] S6.4, Generate modulation waveform SVPWM through the duty ratio of each phase of the upper and lower inverters 上 With SVPWM 下 Then, the modulation waveform is compared with the amplitude of the triangular carrier in one switching cycle to generate six switching signals G that drive the multi-port inverter. x1 , G x2 ;

[0092] S7, controlling the switching actions of the three bridge arms of the multi-port inverter through a switching signal;

[0093] The switch signal G x1 , G x2 Acting on the three bridge arms of the multi-port inverter, using the drive signal G x1 Control switch tube S x1 , driving signal G x1 The complementary signal controls the switch tube S x3 , driving signal G x2 Control switch tube S x2 , driving signal G x2 The complementary signal controls the switch tube S x4 , thereby controlling the switching tubes on each bridge arm to perform switching actions.

[0094] This embodiment is described with reference to examples. Figure 4 , Figure 5 As shown, assuming that the DC side high voltage V H =360V, low voltage V H =180V / 140V / 220V, observe the situation under different DC port voltages. Figures (a), (b), and (c) correspond to the situations of V1=V2, V1>V2, and V1<V2, respectively. The AC side active power P=1kw and reactive power Q=0var. Observing the phase voltage output by the multi-port inverter under variable port voltage, it can be proved that the switching state of the three-level multi-port inverter can be constructed by superposition of the upper inverter and the lower inverter, and the three working states can achieve good tracking performance of the desired grid voltage / current. Although the voltages of the two DC ports are different, the current tracking effect is almost the same, and the ripples of the high-voltage and low-voltage port currents on the DC side are stably controlled to be very small.

[0095] like Figure 6 As shown, by observing the power allocation results of the traditional scheme (asterisk) and the scheme proposed by the present invention (triangle) under different port voltage ratios, it can be concluded that the proposed strategy has a wider power allocation range than the traditional strategy, and it can be found that the scheme proposed by the present invention can collect more renewable energy power and store more energy storage battery power.

[0096] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A power allocation method for a multi-port photovoltaic storage hybrid power generation system based on vector decomposition, characterized in that: The following steps are involved: (1) Calculate the active power of the two DC ports of the multi-port photovoltaic storage hybrid power generation system, that is, the active power output of the high-voltage port and the low-voltage port; Among them, P1 and P2 are the active power of the high-voltage port and the low-voltage port respectively, V1 and V2 are the voltages across the DC-side stabilizing capacitors C1 and C2 respectively, and V H 、V L Represent the voltage of the high voltage port and the low voltage port respectively, i x is the three-phase current output by the multi-port inverter, D xu , D xl They represent the switching signals S of the first switch tube and the second switch tube in the x-phase bridge arm of the multi-port inverter respectively. x1 , S x2 Duty cycle, x = a, b, c represents three phases; (2) According to the power management strategy of the photovoltaic and energy storage hybrid power generation system, the energy management module gives the reference power P of the high-voltage port 1ref , then P 1ref Subtract it from P1, and the difference is passed through the power PI controller to obtain the control parameter ξ; (3) Set the multi-port inverter in the multi-port photovoltaic storage hybrid power generation system to operate in island mode, and obtain the reference voltage vector u on the multi-port inverter side. ref ; (3.1), given the three-phase reference voltage u that is expected to be obtained on the load side of the multi-port photovoltaic and energy storage hybrid power generation system x-ref ; (3.2), the three-phase reference voltage u x-ref After T1 coordinate transformation, the reference voltage u in the dq coordinate system output by the multi-port inverter in island mode is obtained. d-ref 、u q-ref ; The voltage u output by the three-phase voltage detector in the multi-port photovoltaic storage hybrid power generation system g After T1 coordinate transformation, the voltage u of the dq axis is obtained d 、u q ; The current I output by the three-phase current detector g After T1 coordinate transformation, the current I in the dq coordinate system is obtained d ,I q ; (3.3), will u d-ref and u d The difference is then passed through the d-axis voltage PI controller to obtain the d-axis current Will and I d The difference is then passed through the d-axis current PI controller to obtain the d-axis voltage Then with u d-ref Sum and get the final output voltage of the d-axis (3.4), will u q-ref and u q The difference is then passed through the q-axis voltage PI controller to obtain the q-axis current Will and I q The difference is then passed through the q-axis current PI controller to obtain the q-axis voltage Then with u q-ref Sum and get the final output voltage of the q axis (3.5) The final output voltage of the dq axis Through T2 coordinate transformation, the voltage value u of the multi-port inverter in the αβ coordinate system is obtained α-ref 、u β-ref ; (3.6), the voltage value u α-ref 、u β-ref Through T3 coordinate transformation, the reference voltage vector u on the multi-port inverter side is obtained ref ; (4) The multi-port inverter is equivalently modeled as two upper and lower two-level inverters, where the DC link voltage of the upper inverter is V1 and the DC link voltage of the lower inverter is V2; the equivalent switch tube of the upper inverter is S x1 , S x3 , the equivalent switch tube of the lower inverter is denoted as S x2 , S x4 ; S x1 , S x2 , S x3 , S x4 They respectively represent the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube in the x-th phase bridge arm of the multi-port inverter; (5) In two-level space vector modulation, the space voltage vector is divided into the following six sectors according to the phase θ: (6) Generate a switching signal for driving a multi-port inverter based on a modulation method based on vector decomposition; (6.1), according to the reference voltage vector u ref The phase of the reference voltage vector is determined to determine which sector the reference voltage vector falls in. Then, the expression of the residence time corresponding to each vector is obtained by combining the two adjacent non-zero vectors and the zero vector that constitute the sector in different times: Among them, T s is the switching period, u k1 、u k2 、u k0 Two adjacent non-zero vectors and a zero vector that form the kth sector, k=1, 2, 3, 4, 5, 6 represents 6 sector numbers; is the dwell time corresponding to each vector; (6.2) Based on the formula in step (6.1), the upper and lower inverters respectively use the traditional two-level space vector modulation strategy to generate the dwell time of the switching signal of each phase, where the dwell time of the lower inverter is recorded as T Lz , the residence time of the upper inverter is recorded as T Uz , z=0,1,2 represents two adjacent non-zero vectors and a zero vector; (6.3) Calculate the duty cycle of each phase of the upper inverter and the lower inverter based on the classic PWM strategy; Among them, d xu is the duty cycle of each phase of the upper inverter, d xl is the duty cycle of each phase of the lower inverter; (6.4) Generate the modulation waveform SVPWM through the duty cycle of each phase of the upper and lower inverters 上 With SVPWM 下 Then, the modulation waveform is compared with the amplitude of the triangular carrier in one switching cycle to generate six switching signals G that drive the multi-port inverter. x1 , G x2 ; (7) Controlling the switching actions of the three bridge arms of the multi-port inverter through a switching signal; The switch signal G x1 , G x2 Acting on the three bridge arms of the multi-port inverter, using the drive signal G x1 Control switch tube S x1 , driving signal G x1 The complementary signal controls the switch tube S x3 , driving signal G x2 Control switch tube S x2 , driving signal G x2 The complementary signal controls the switch tube S x4 , thereby controlling the switching tubes on each bridge arm to perform switching actions.

2. The power allocation method for a multi-port photovoltaic-storage hybrid power generation system based on vector decomposition according to claim 1 is characterized in that: The formula for the T1 coordinate transformation is: Where θ is the phase angle, u d-ref 、u q-ref is the reference voltage in the dq coordinate system.

3. The power allocation method for a multi-port photovoltaic-storage hybrid power generation system based on vector decomposition according to claim 1 is characterized in that: The formula for the T2 coordinate transformation is: Among them, u α-ref 、u β-ref is the voltage value of the multi-port inverter in the αβ coordinate system.

4. The power allocation method for a multi-port photovoltaic-storage hybrid power generation system based on vector decomposition according to claim 1 is characterized in that: The formula for the T3 coordinate transformation is: Among them, u ref is the reference voltage vector on the multi-port inverter side.

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