Resonance control method for photovoltaic power generation system

Abstract

The invention provides a resonance control method for a photovoltaic power generation system, and relates to the technical field of new energy, and the method specifically comprises the following steps: taking a three-phase load current as an input, and extracting a fundamental wave load current based on a resonance controller; based on the sampling hold circuit, taking the active voltage phase component as the input of a first zero crossing detector to obtain a load current active power component; based on the sampling hold circuit, taking the reactive voltage phase component as the input of a second zero crossing detector to obtain a load current reactive power component; multiplying the active voltage component by the active current to estimate an active reference component of the power grid current; multiplying the reactive voltage component by the reactive current to estimate a reactive reference component of the power grid current; and adding the active reference component and the reactive reference component of each phase to obtain a current reference component of each phase. According to the technical scheme, the problems that in the prior art, a photovoltaic power generation system is low in efficiency and large in energy loss are solved.

Description

Technical Field

[0001] This invention relates to the field of new energy grid connection technology, and specifically to a resonant control method for photovoltaic power generation systems. Background Technology

[0002] Photovoltaic (PV) power generation systems utilize the photovoltaic effect to convert solar radiation into direct current (DC) electricity. PV systems have become an important part of the renewable energy industry and are widely used in residential, industrial, and commercial sectors. However, due to factors such as variations in solar radiation and grid fluctuations, PV systems face challenges in power output and grid connection. Traditional PV system control methods may fail to adjust the system's operating state in real time, leading to inefficiency or energy loss. Resonant control algorithms can dynamically adjust the PV system's operating state based on solar radiation and grid demand, thereby improving system efficiency and stability. This algorithm can reduce energy waste and enhance the performance of PV systems.

[0003] Therefore, there is a need for a resonant control method that can improve the efficiency and stability of photovoltaic power generation systems. Summary of the Invention

[0004] The main objective of this invention is to provide a resonant control method for photovoltaic power generation systems to solve the problems of low efficiency and large energy loss in existing photovoltaic power generation systems.

[0005] To achieve the above objectives, the present invention provides a resonant control method for a photovoltaic power generation system, specifically comprising the following steps:

[0006] S1, taking the three-phase load current as input, extracts the fundamental load current of phase a, phase b and phase c based on the resonant controller;

[0007] S2, based on the sample-and-hold circuit, uses the active voltage phase component as the input of the first zero-crossing detector to obtain the load current active power component;

[0008] S3, based on the sample-and-hold circuit, uses the reactive voltage phase component as the input of the second zero-crossing detector to obtain the reactive power component of the load current;

[0009] S4. Add the signal from the PI regulator to the active component of the load current to obtain the active current. Multiply the active voltage component by the active current to estimate the active reference component of the grid current.

[0010] S5 adds the signal from the PI regulator to the reactive component of the load current to obtain the reactive current, and multiplies the reactive voltage component by the reactive current to estimate the reactive reference component of the grid current.

[0011] S6. Add the active and reactive reference components of each phase to obtain the current reference components of each phase.

[0012] Furthermore, taking the extraction of the fundamental active component of the load current in phase a as an example, step S1 specifically includes the following steps:

[0013] S1.1, the resonant controller is represented as:

[0014]

[0015] Among them, i fLa It is the fundamental load current of phase a, i La It is the input phase a load current, ω n G1 is the frequency, G1 is the gain, and s is the Laplace operator.

[0016] Furthermore, step S1 also includes the following steps:

[0017] S1.2, the state-space representation of the resonance-based control algorithm is as follows:

[0018]

[0019] e = (i La -G1i fLa );

[0020]

[0021] Where e is the signal after resonant control feedback, and i L1 i L2 i L3 These are all intermediate parameters.

[0022] Furthermore, step S2 specifically includes the following steps:

[0023] S2.1, calculate the active voltage phase component and use it as the input to the first zero-crossing detector ZCD1:

[0024]

[0025] Among them, W pa W pb and W pc These are the active voltage components of phases a, b, and c, respectively, v sa v sb and v sc The sensed voltages V for phases a, b, and c are respectively. t This represents the fundamental component of the positive-sequence PCC voltage.

[0026] Furthermore, step S2 also includes the following steps:

[0027] S2.2, the output of the first zero-crossing detector ZCD1 is used to trigger the first synchronization channel module SCH1, i fLa Also input to the first synchronization channel module SCH1 to obtain the fundamental active component i of the a-phase load current. pLa i fLb Inputting the first synchronization channel module SCH1, we obtain the fundamental active component i of the phase b load current. pLb i fLc Input the first synchronization channel module SCH1 to obtain the fundamental active component i of the c-phase load current. pLc .

[0028] Furthermore, step S2 also includes the following steps:

[0029] S2.3, Calculate the active power component i of the load current. pLavg :

[0030]

[0031] Furthermore, step S3 specifically includes the following steps:

[0032] S3.1, calculate the reactive voltage phase component and use it as the input to the second zero-crossing detector ZCD2:

[0033]

[0034] Among them, W qa W qb and W qc These are the reactive voltage components of phases a, b, and c, respectively.

[0035] Furthermore, step S3 also includes the following steps:

[0036] S3.2, the output of the second zero-crossing detector ZCD2 is used to trigger the second synchronization channel module SCH2, i fLa Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the a-phase load current. qLa i fLb Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the phase b load current. qLb i fLc Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the c-phase load current. qLc .

[0037] Furthermore, step S3 also includes the following steps:

[0038] S3.3, Calculate the reactive power component i of the load current.qLavg :

[0039]

[0040] Furthermore, step S4 specifically includes:

[0041] i PLnet =i pLavg +i loss ;

[0042] i psa =i PLnet W pa ;

[0043] i psb =i PLnet W pb ;

[0044] i psc =i PLnet W pc ;

[0045] Among them, i PLnet For active current, i psa i psb and i psc These are the active current reference components for phases a, b, and c, respectively, i loss This is the signal from the PI controller.

[0046] Furthermore, step S5 specifically includes:

[0047] i QLnet =-i qLavg +i qq ;

[0048] i qsa =i QLnet W pc ;

[0049] i qsb =i QLnet W pb ;

[0050] i qsc =i QLne tW pc ;

[0051] Among them, i QLnet For reactive current, i qsa i qsb and i qsc These are the reactive current reference components for phases a, b, and c, respectively, i qq Estimate the reactive component of the voltage source converter (VSC) current for the PI regulator.

[0052] Furthermore, step S6 specifically includes:

[0053] i sa =i qsa +i psa ;

[0054] i sb =i qsb +i psb ;

[0055] i sc =i qsc +i psc ;

[0056] Among them, i sa i sb and i sc These are the grid reference currents for phases a, b, and c, respectively.

[0057] The present invention has the following beneficial effects:

[0058] Traditional photovoltaic (PV) power generation systems may suffer from low energy utilization due to factors such as variations in sunlight and environmental influences. The goal of this invention is to optimize the operating state of the PV power generation system through a resonant control algorithm, thereby improving energy conversion efficiency and enabling the system to more effectively capture solar radiation energy and convert it into electrical energy.

[0059] Traditional photovoltaic (PV) power generation systems may respond slowly to grid fluctuations or load changes, leading to system instability or inability to meet power demands. This invention aims to achieve matching between the PV array and the power grid through real-time adjustment and optimization of a resonant control algorithm.

[0060] In traditional photovoltaic (PV) power generation systems, energy waste occurs due to inflexible or untimely adjustments to the operating status. This invention aims to optimize the operating status of the PV power generation system through intelligent adjustments using a resonant control algorithm, based on changes in sunlight and grid demand, thereby reducing energy waste and improving the overall energy efficiency of the system. Attached Figure Description

[0061] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0062] Figure 1 A flowchart of a resonant control method for a photovoltaic power generation system according to the present invention is shown. Detailed Implementation

[0063] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] Example 1

[0065] like Figure 1 The resonant control method for a photovoltaic power generation system shown includes the following steps:

[0066] S1, taking the three-phase load current as input, extracts the fundamental load current of phase a, phase b and phase c based on the resonant controller;

[0067] S2, based on the sample-and-hold circuit, uses the active voltage phase component as the input of the first zero-crossing detector to obtain the load current active power component;

[0068] S3, based on the sample-and-hold circuit, uses the reactive voltage phase component as the input of the second zero-crossing detector to obtain the reactive power component of the load current;

[0069] S4. Add the signal from the PI regulator to the active component of the load current to obtain the active current. Multiply the active voltage component by the active current to estimate the active reference component of the grid current.

[0070] S5 adds the signal from the PI regulator to the reactive component of the load current to obtain the reactive current, and multiplies the reactive voltage component by the reactive current to estimate the reactive reference component of the grid current.

[0071] S6. Add the active and reactive reference components of each phase to obtain the current reference components of each phase.

[0072] Specifically, taking the extraction of the fundamental active component of the load current in phase a as an example, step S1 specifically includes the following steps:

[0073] S1.1, the resonant controller is represented as:

[0074]

[0075] Among them, i fLa It is the fundamental load current of phase a, i La It is the input phase a load current, ω n G1 is the frequency, G1 is the gain, and s is the Laplace operator.

[0076] Specifically, step S1 also includes the following steps:

[0077] S1.2, the state-space representation of the resonance-based control algorithm is as follows:

[0078]

[0079] e = (i La -G1i fLa );

[0080]

[0081] Where e is the signal after resonant control feedback, and i L1 i L2 i L3 These are intermediate parameters.

[0082] Specifically, step S2 includes the following steps:

[0083] S2.1, calculate the active voltage phase component and use it as the input to the first zero-crossing detector ZCD1:

[0084]

[0085] Among them, W pa W pb and W pc These are the active voltage components of phases a, b, and c, respectively, v sa v sb and v sc The sensed voltages V for phases a, b, and c are respectively. t This represents the fundamental component of the positive-sequence PCC voltage.

[0086] Specifically, step S2 also includes the following steps:

[0087] S2.2, the output of the first zero-crossing detector ZCD1 is used to trigger the first synchronization channel module SCH1, i fLa Also input to the first synchronization channel module SCH1 to obtain the fundamental active component i of the a-phase load current. pLa i fLb Inputting the first synchronization channel module SCH1, we obtain the fundamental active component i of the phase b load current. pLb i fLc Input the first synchronization channel module SCH1 to obtain the fundamental active component i of the c-phase load current. pLc .

[0088] Specifically, step S2 also includes the following steps:

[0089] S2.3, Calculate the active power component i of the load current. pLavg :

[0090]

[0091] Specifically, step S3 includes the following steps:

[0092] S3.1, calculate the reactive voltage phase component and use it as the input to the second zero-crossing detector ZCD2:

[0093]

[0094] Among them, W qa W qb and W qc These are the reactive voltage components of phases a, b, and c, respectively.

[0095] Specifically, step S3 also includes the following steps:

[0096] S3.2, the output of the second zero-crossing detector ZCD2 is used to trigger the second synchronization channel module SCH2, i fLa Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the a-phase load current. qLa i fLb Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the phase b load current. qLb i fLc Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the c-phase load current. qLc .

[0097] Specifically, step S3 also includes the following steps:

[0098] S3.3, Calculate the reactive power component i of the load current. qLavg :

[0099]

[0100] Specifically, step S4 is as follows:

[0101] i PLnet =i pLavg +i loss ;

[0102] i psa =i PLnet W pa ;

[0103] i psb =i PLnet W pb ;

[0104] i psc =i PLnet Wpc ;

[0105] Among them, i PLnet For active current, i psa i psb and i psc These are the active current reference components for phases a, b, and c, respectively, i loss This is the signal from the PI controller.

[0106] Specifically, step S5 is as follows:

[0107] i QLnet =-i qLavg +i qq ;

[0108] i qsa =i QLnet W pc ;

[0109] i qsb =i QLnet W pb ;

[0110] i qsc =i QLnet W pc ;

[0111] Among them, i QLnet For reactive current, i qsa i qsb and i qsc These are the reactive current reference components for phases a, b, and c, respectively, i qq Estimate the reactive component of the voltage source converter (VSC) current for the PI regulator.

[0112] Specifically, step S6 is as follows:

[0113] i sa =i qsa +i psa ;

[0114] i sb =i qsb +i psb ;

[0115] i sc =i qsc +i psc ;

[0116] Among them, i sa i sb and i sc These are the grid reference currents for phases a, b, and c, respectively.

[0117] The present invention has the following beneficial effects:

[0118] Traditional photovoltaic (PV) power generation systems may suffer from low energy utilization due to factors such as variations in sunlight and environmental influences. The goal of this invention is to optimize the operating state of the PV power generation system through a resonant control algorithm, thereby improving energy conversion efficiency and enabling the system to more effectively capture solar radiation energy and convert it into electrical energy.

[0119] Traditional photovoltaic (PV) power generation systems may respond slowly to grid fluctuations or load changes, leading to system instability or inability to meet power demands. This invention aims to achieve matching between the PV array and the power grid through real-time adjustment and optimization of a resonant control algorithm.

[0120] In traditional photovoltaic (PV) power generation systems, energy waste occurs due to inflexible or untimely adjustments to the operating status. This invention aims to optimize the operating status of the PV power generation system through intelligent adjustments using a resonant control algorithm, based on changes in sunlight and grid demand, thereby reducing energy waste and improving the overall energy efficiency of the system.

[0121] Example 2

[0122] This embodiment provides a control algorithm for extracting the fundamental component of the load current and estimating in-phase and quadrature voltage templates. During the estimation of the fundamental component of the load current, sample-and-hold logic and phase templates can be used to extract other harmonic components of the load current. By adjusting and matching the sample-and-hold logic and phase templates, the harmonic components in the load current can be accurately estimated and separated from the fundamental component. To specifically eliminate errors caused by load imbalance, averaging and correction techniques can be used. By calculating and correcting the average values ​​of the fundamental active and reactive components, the effects of load imbalance can be accurately compensated, and the estimation accuracy of the reference grid current can be improved. In the resonance-based control algorithm module, an adaptive adjustment strategy can be introduced to specifically improve the stability and robustness of the system. By monitoring the dynamic changes of the load current and the frequency response of the system, the parameters of the resonant controller can be adjusted in real time to adapt to different operating conditions and load characteristic changes, thereby ensuring the stability and performance of the system.

[0123] This embodiment uses the real and imaginary parts of the load current to estimate the reference grid current. Useful signals for the system include the three-phase sensed voltage (V... sa v sb v sc ), load current (i La i Lb i Lc ) and DC voltage (v dc ).

[0124] First, the input voltage Vt A low-pass filter is used to eliminate the negative-sequence PCC voltage and extract the fundamental component of the positive-sequence PCC voltage. Then, the load current is passed as input to a resonance-based control algorithm module, whose output is the fundamental load current. In extracting the fundamental load current, the frequency ω... n The gain G1 plays a crucial role. The value of G1 is set to 50, and it plays a vital role in extracting the fundamental load current from the contaminated load current. Placing G1 in the feedback loop of the resonant controller ensures asymptotic stability of the system and guarantees zero steady-state error in the extracted fundamental load current.

[0125] To estimate the fundamental active component of the load current in phase 'a', sample-and-hold logic is used to sample similar fundamental active components and store their values ​​for a period of time. The output of the zero-crossing detector is used to trigger the synchronization channel module. To obtain the trigger pulse, the phase component of the active voltage of phase 'a' (W... pa The sample-and-hold circuit is used as the input to the zero-crossing detector. The output signal of the sample-and-hold circuit is considered as the fundamental active component (i) of the phase 'a' load current. pLa Similarly, using appropriate techniques, the fundamental active components (ib and ic) of the load currents in phases 'b' and 'c' are extracted. pLb and i pLc ).

[0126] To extract the fundamental reactive component of the load current in phase 'a', another sample-and-hold logic is used, with the in-phase template as the input to another zero-crossing detector, which provides a trigger pulse to the sample-and-hold logic. The output of this sample-and-hold logic is the fundamental reactive component of the load current in phase 'a'. Similarly, the fundamental reactive components (ib and ic) of phases 'b' and 'c' are estimated using a similar method. qLa i qLb and i qLc These estimated signals are processed by an absolute value module. By averaging these power components, load imbalances can be addressed, and the results can be used to estimate the three-phase reference grid current.

[0127] Traditional photovoltaic (PV) power generation systems may suffer from low energy utilization due to factors such as variations in sunlight and environmental influences. The goal of this invention is to optimize the operating state of the PV power generation system through a resonant control algorithm, thereby improving energy conversion efficiency and enabling the system to more effectively capture solar radiation energy and convert it into electrical energy.

[0128] Traditional photovoltaic (PV) power generation systems may respond slowly to grid fluctuations or load changes, leading to system instability or inability to meet power demands. This invention aims to achieve matching between the PV array and the power grid through real-time adjustment and optimization of a resonant control algorithm.

[0129] In traditional photovoltaic (PV) power generation systems, energy waste occurs due to inflexible or untimely adjustments to the operating status. This invention aims to optimize the operating status of the PV power generation system through intelligent adjustments using a resonant control algorithm, based on changes in sunlight and grid demand, thereby reducing energy waste and improving the overall energy efficiency of the system.

[0130] Example 3

[0131] In this embodiment, the real and imaginary parts of the load current are used to estimate the reference grid current. Useful signals for this control technique include the three-phase sensed voltage (V... sa v sb v sc ), load current (i La i Lb i Lc ) and DC voltage (v dc ).

[0132] The formula for the active voltage phase component is as follows:

[0133]

[0134] Among them, W pa W pb and W pc These are the active voltage components of phases a, b, and c, respectively, v sa v sb and v sc The sensed voltages V for phases a, b, and c are respectively. t This is the terminal voltage.

[0135] The method for estimating the reactive voltage phase component is as follows:

[0136]

[0137] Among them, W qa W qb and W qc These are the reactive voltage components of phases a, b, and c, respectively.

[0138] V t for:

[0139]

[0140] V t To eliminate negative sequence voltage from PCC voltage using LPF and realize the fundamental component of positive sequence PCC voltage.

[0141] The input to the resonant-based control algorithm module is the load current, and the output is the basic load current. The resonant controller is expressed by the given expression:

[0142]

[0143] Where, ω n Here, G1 is the frequency, and G1 is the gain, which plays a crucial role in extracting the fundamental component from the contaminated load current. The value of G1 is set to 50. When G1 is placed in the feedback loop of the resonant controller, it ensures the system is asymptotically stable. Furthermore, it guarantees that the extracted fundamental load current has zero steady-state error. The state-space representation of the resonant-based control algorithm is as follows:

[0144]

[0145] e = (i La -G1i fLa );

[0146]

[0147] Where e is the signal after resonant control feedback, and i L1 i L2 i L3 These are all intermediate parameters.

[0148] By using these equations, the fundamental component of the load current in phase 'a' can be extracted. Similarly, phases 'b' and 'c' (respectively i) can be extracted. fLb and i fLc The fundamental component of the load current was also extracted.

[0149] To estimate the fundamental active component of the load current in phase 'a', sample-and-hold logic is used to sample similar fundamental active components and store their values ​​for a period of time. The output of the zero-crossing detector is used to trigger this module. The active voltage phase component of phase 'a' (W...) is used... pa The sample-and-hold circuit is used as the input to the zero-crossing detector. The output signal of the sample-and-hold circuit is considered as the fundamental active component (i) of the phase 'a' load current. pLa Correspondingly, the fundamental active components (i) of the load currents in phases 'b' and 'c' are... pLb and i pLc ) was extracted.

[0150] To extract the fundamental reactive component of the load current in phase 'a', another sample-and-hold logic is used, with the in-phase template as the input to another zero-crossing detector, which provides a trigger pulse to the sample-and-hold logic. The output of this sample-and-hold logic is the fundamental reactive component of the load current in phase 'a'. Similarly, the fundamental reactive components (i...) of phases 'b' and 'c' are also extracted. qLb and i qLcThe active power component of the load current is also estimated. The estimated signal is processed by the absolute value module. The average value of these power components handles load imbalance and is used to estimate the three-phase reference grid current. The magnitude of the active power component of the load current is calculated as follows:

[0151]

[0152] Similarly, the magnitude of the reactive power component of the load current is calculated as follows:

[0153]

[0154] The signal from the PI controller is called i loss This component is compared with the active component i of the load current. PLavg After adding them, estimate i PLnet It is represented as:

[0155] i PLnet =i pLavg +i loss ;

[0156] Subsequently, by interpolating the active voltage phase component with i PLnet The active reference component of the grid current is estimated by multiplication. It is expressed as follows:

[0157] i psa =i PLnet W pa ;

[0158] i psb =i PLnet W pb ;

[0159] i psc =i PLnet W pc ;

[0160] The assessed value is input to the PI regulator, which estimates the reactive component (IVSC) of the current. qq ), and then combine this component with the reactive component of the load current i qLavg After adding, estimate i QLnet It is represented as:

[0161] i QLnet =-i qLavg +i qq ;

[0162] By interchanging the reactive voltage phase component with i QLnet The reactive reference component of the grid current is estimated by multiplication, and the formula is as follows:

[0163] i qsa =i QLnet W pc;

[0164] i qsb =i QLnet W pb ;

[0165] i qsc =i QLnet Q pc ;

[0166] i sa =i qsa +i psa ;

[0167] i sb =i qsb +i psb ;

[0168] i sc =i qsc +i psc ;

[0169] Among them, i sa i sb and i sc These are the grid reference currents for phases a, b, and c, respectively.

[0170] The above formula is used to evaluate the grid reference current. By comparing the sensed gate current with these reference currents, the resulting estimated signal is input to the hysteresis controller and generates the grid-connected VSC strobe signal.

[0171] This invention uses resonant control technology to estimate the complex power requirements of the load, which can optimize the operation of the power system, reduce harmonics in the power grid, and improve the power factor.

[0172] This invention also incorporates a load balancing function, which can balance and optimize the load in the system, improve the stability and reliability of the system, and reduce the operating cost of the system.

[0173] Example 4

[0174] This embodiment provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements a resonant control method for a photovoltaic power generation system, specifically including the following steps:

[0175] S1, taking the three-phase load current as input, extracts the fundamental load current of phase a, phase b and phase c based on the resonant controller;

[0176] S2, based on the sample-and-hold circuit, uses the active voltage phase component as the input of the first zero-crossing detector to obtain the load current active power component;

[0177] S3, based on the sample-and-hold circuit, uses the reactive voltage phase component as the input of the second zero-crossing detector to obtain the reactive power component of the load current;

[0178] S4. Add the signal from the PI regulator to the active component of the load current to obtain the active current. Multiply the active voltage component by the active current to estimate the active reference component of the grid current.

[0179] S5 adds the signal from the PI regulator to the reactive component of the load current to obtain the reactive current, and multiplies the reactive voltage component by the reactive current to estimate the reactive reference component of the grid current.

[0180] S6. Add the active and reactive reference components of each phase to obtain the current reference components of each phase.

[0181] Specifically, taking the extraction of the fundamental active component of the load current in phase a as an example, step S1 specifically includes the following steps:

[0182] S1.1, the resonant controller is represented as:

[0183]

[0184] Among them, i fLa It is the fundamental load current of phase a, i La It is the input phase a load current, ω n G1 is the frequency, G1 is the gain, and s is the Laplace operator.

[0185] Specifically, step S1 also includes the following steps:

[0186] S1.2, the state-space representation of the resonance-based control algorithm is as follows:

[0187]

[0188] e = (i La -G1i fLa );

[0189]

[0190] Where e is the signal after resonant control feedback, and i L1 i L2 i L3 These are all intermediate parameters.

[0191] Specifically, step S2 includes the following steps:

[0192] S2.1, calculate the active voltage phase component and use it as the input to the first zero-crossing detector ZCD1:

[0193]

[0194]

[0195] Among them, W pa W pb and W pc These are the active voltage components of phases a, b, and c, respectively, v sa v sb and v sc The sensed voltages V for phases a, b, and c are respectively. t This represents the fundamental component of the positive-sequence PCC voltage.

[0196] Specifically, step S2 also includes the following steps:

[0197] S2.2, the output of the first zero-crossing detector ZCD1 is used to trigger the first synchronization channel module SCH1, i fLa Also input to the first synchronization channel module SCH1 to obtain the fundamental active component i of the a-phase load current. pLa i fLb Inputting the first synchronization channel module SCH1, we obtain the fundamental active component i of the phase b load current. pLb i fLc Input the first synchronization channel module SCH1 to obtain the fundamental active component i of the c-phase load current. pLc .

[0198] Specifically, step S2 also includes the following steps:

[0199] S2.3, Calculate the active power component i of the load current. pLavg :

[0200]

[0201] Specifically, step S3 includes the following steps:

[0202] S3.1, calculate the reactive voltage phase component and use it as the input to the second zero-crossing detector ZCD2:

[0203]

[0204] Among them, W qa W qb and W qc These are the reactive voltage components of phases a, b, and c, respectively.

[0205] Specifically, step S3 also includes the following steps:

[0206] S3.2, the output of the second zero-crossing detector ZCD2 is used to trigger the second synchronization channel module SCH2, i fLa Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the a-phase load current. qLa i fLb Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the phase b load current. qLb i fLc Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the c-phase load current. qLc .

[0207] Specifically, step S3 also includes the following steps:

[0208] S3.3, Calculate the reactive power component i of the load current. qLavg :

[0209]

[0210] Specifically, step S4 is as follows:

[0211] i PLnet =i pLavg +i loss ;

[0212] i psa =i PLnet W pa ;

[0213] i psb =i PLnet W pb ;

[0214] i psc =i PLnet W pc ;

[0215] Among them, i PLnet For active current, i psa i psb and i psc These are the active current reference components for phases a, b, and c, respectively, i loss This is the signal from the PI controller.

[0216] Specifically, step S5 is as follows:

[0217] i QLnet =-i qLavg +i qq ;

[0218] i qsa =i QLnet W pc ;

[0219] i qsb =i QLnet W pb ;

[0220] i qsc =i QLnet W pc ;

[0221] Among them, i QLnet For reactive current, i qsa i qsb and i qsc These are the reactive current reference components for phases a, b, and c, respectively, i qq Estimate the reactive component of the voltage source converter (VSC) current for the PI regulator.

[0222] Specifically, step S6 is as follows:

[0223] i sa =i qsa +i psa ;

[0224] i sb =i qsb +i psb ;

[0225] i sc =i qsc +i psc ;

[0226] Among them, i sa i sb and i sc These are the grid reference currents for phases a, b, and c, respectively.

[0227] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A resonant control method for a photovoltaic power generation system, characterized in that, Specifically, the steps include the following: S1, taking the three-phase load current as input, extracts the fundamental load current of phase a, phase b and phase c based on the resonant controller; S2, based on the sample-and-hold circuit, uses the active voltage phase component as the input of the first zero-crossing detector to obtain the load current active power component; S3, based on the sample-and-hold circuit, uses the reactive voltage phase component as the input of the second zero-crossing detector to obtain the reactive power component of the load current; S4. Add the signal from the PI regulator to the active component of the load current to obtain the active current. Multiply the active voltage component by the active current to estimate the active reference component of the grid current. S5 adds the signal from the PI regulator to the reactive component of the load current to obtain the reactive current, and multiplies the reactive voltage component by the reactive current to estimate the reactive reference component of the grid current. S6. Add the active and reactive reference components of each phase to obtain the current reference components of each phase.

2. The resonant control method for a photovoltaic power generation system according to claim 1, characterized in that, Taking the extraction of the fundamental active component of the load current in phase a as an example, step S1 specifically includes the following steps: S1.1, the resonant controller is represented as: where i fLa is the a-phase fundamental load current, i La is the input a-phase load current, ω n is the frequency, G1 is the gain, and s is the Laplace operator.

3. The resonant control method for a photovoltaic power generation system according to claim 2, characterized in that, Step S1 also includes the following steps: S1.2, the state-space representation of the resonance-based control algorithm is as follows: e = (i La - G1i fLa ); Wherein, e is the signal after resonance control feedback, i L1 , i L2 , i L3 are intermediate parameters.

4. The resonant control method for a photovoltaic power generation system according to claim 1, characterized in that, Step S2 specifically includes the following steps: S2.1, calculate the active voltage phase component and use it as the input to the first zero-crossing detector ZCD1: where W pa , W pb and W pc are the active voltage components of phase a, b and c respectively, v sa , v sb and v sc are the sensed voltages of phase a, b and c respectively, V t is the fundamental component of the positive sequence PCC voltage.

5. The resonant control method for a photovoltaic power generation system according to claim 4, characterized in that, Step S2 also includes the following steps: S2.2, the output of the first zero-crossing detector ZCD1 is used to trigger the first synchronization channel module SCH1, i fLa Also input to the first synchronization channel module SCH1 to obtain the fundamental active component i of the a-phase load current. pLa i fLb Inputting the first synchronization channel module SCH1, we obtain the fundamental active component i of the phase b load current. pLb i fLc Input the first synchronization channel module SCH1 to obtain the fundamental active component i of the c-phase load current. pLc .

6. The resonant control method for a photovoltaic power generation system according to claim 5, characterized in that, Step S2 also includes the following steps: S2.3, Calculate the active power component i of the load current. pLavg :

7. The resonant control method for a photovoltaic power generation system according to claim 1, characterized in that, Step S3 specifically includes the following steps: S3.1, calculate the reactive voltage phase component and use it as the input to the second zero-crossing detector ZCD2: Among them, W qa W qb and W qc These are the reactive voltage components of phases a, b, and c, respectively.

8. The resonant control method for a photovoltaic power generation system according to claim 7, characterized in that, Step S3 also includes the following steps: S3.2, the output of the second zero-crossing detector ZCD2 is used to trigger the second synchronization channel module SCH2, i fLa Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the a-phase load current. qLa i fLb Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the phase b load current. qLb i fLc Input the second synchronization channel module SCH2 to obtain the fundamental reactive component i of the c-phase load current. qLc .

9. A resonant control method for a photovoltaic power generation system according to claim 8, characterized in that, Step S3 also includes the following steps: S3.3, Calculate the reactive power component i of the load current. qLavg :

10. A resonant control method for a photovoltaic power generation system according to claim 1, characterized in that, Step S4 is as follows: i PLnet =i pLavg +i loss ; i psa =i PLnet W pa ; i psb =i PLnet W pb ; i psc =i PLnet W pc ; Among them, i PLnet For active current, i psa i psb and i psc These are the active current reference components for phases a, b, and c, respectively, i loss This is the signal from the PI controller.

11. The resonant control method for a photovoltaic power generation system according to claim 1, characterized in that, Step S5 is as follows: i QLnet =-i qLavg +i qq ; i qsa =i QLnet W pc ; i qsb =i QLnet W pb ; i qsc =i QLnet W pc ; Among them, i QLnet For reactive current, i qsa i qsb and i qsc These are the reactive current reference components for phases a, b, and c, respectively, i qq Estimate the reactive component of the voltage source converter (VSC) current for the PI regulator.

12. The resonant control method for a photovoltaic power generation system according to claim 1, characterized in that, Step S6 is as follows: i sa =i qsa +i psa ; i sb =i qsb +i psb ; i sc =i qsc +i psc ; Among them, i sa i sb and i sc These are the grid reference currents for phases a, b, and c, respectively.

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