Iot photovoltaic power generation energy control system and control method based on ga-svm modulation

Abstract

The application discloses a kind of GA-SVM modulation based on Internet of Things photovoltaic power generation control system and control method, first to the parameter setting of first current modulation module, second current modulation module, PR controller and wave filter, receive the voltage, current of smart grid public point, inverter output end three-phase current, photovoltaic cell direct current output voltage;Real-time acquisition and judge whether to generate first reference current and / or second reference current, determine the optimal speed of response in first current modulation module and second current modulation module;If second current modulation module is the optimal speed of response, corresponding switching is carried out to make the connection line between second current modulation module and SVM wave module be connected, voltage V a 、 b 、 V0 is obtained by using second reference current conversion;Otherwise, voltage V a 、 b 、 V0 is obtained by using first reference current conversion;And based on SVM wave, control inverter works, response speed is fast, and power generation efficiency is high.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of Internet of Things and smart grid power transmission and distribution, and relates to an Internet of Things photovoltaic power generation energy control system and a control method based on GA-SVM modulation. BACKGROUND

[0002] As a basic unit of global energy internet, the smart grid has high reactance ratio and unbalanced load curve with large-scale access of renewable energy such as photovoltaic, wind, biomass, tide, fuel cell and geothermal energy to the existing traditional power grid. In the power distribution system, various AC / DC monitoring devices, electronic power meters, and many voltage and current sensors and electronic chokes used in the smart grid and the Internet of Things are introduced. When a nonlinear load is applied to the system, the power supply current tends to be non-sinusoidal and has significant harmonic content loss, which damages the power quality. In a three-phase unbalanced system, the flow of harmonic current in the conductor leads to low efficiency, and the intermittency of wind, tidal and solar photovoltaic (PV) power generation and power electronic equipment such as inverters leads to power imbalance and voltage distribution imbalance at the point of common coupling (PCC), resulting in unbalanced faults, voltage surges and power oscillations, which cannot realize low-voltage and high-voltage ride-through. This garbage energy hazard and paralysis of the smart grid, power conversion equipment, power transformation equipment and power distribution system. In addition to the above problems, the existing reactive power assessment technology for power metering and for monitoring and controlling active supply, active consumption and external power exchange within the power grid also has the following problems and defects:

[0003] 1. Under the condition of three-phase balance, the current controller running in the positive sequence reference frame (PSRF) is used to eliminate the influence of the intermittent characteristics of photovoltaic power generation on the voltage distribution at the point of common coupling (PCC) of the smart grid, but it cannot maintain the required voltage when the voltage at the point of common coupling (PCC) surges and surges. Secondly, it can only inject balanced current into the system, which may cause power switch current to surge during unbalance, resulting in temperature rise, reduced life, burning, and causing power quality problems at the output of the inverter.

[0004] 2. Voltage rise and imbalance generally use active power limiting and reactive power compensation control methods. Active power limiting is used when the maximum photovoltaic capacity of the photovoltaic system connected to the grid is 15% of the peak load. Reactive power compensation control is used when the maximum photovoltaic capacity of the photovoltaic system connected to the grid exceeds 15% of the peak load, and the corresponding voltage does not exceed the upper limit of the voltage. This fixed actual power limiting is not feasible for changing system operating conditions, and limits the application range and further development of large-scale renewable energy access to the smart grid.

[0005] 3. The existing photovoltaic grid-connected controller provides active power to the system through maximum power point tracking (MPPT), generates reactive current reference to provide reactive power and compensation according to the strict standard and connection code by estimating the minimum phase voltage difference between two instances at the PCC, the reactive current reference increases the voltage of the healthy phase together with the fault phase during the fault, in addition, the size of the filter capacitor increases with the increase of photovoltaic capacity, resulting in the increase of DC bus voltage fluctuation, the existing technology does not consider the reactive power generated by the filter capacitor under unbalanced state, which causes error in the calculation of reactive power set point, thereby causing grid voltage curve fluctuation problem.

[0006] 4. The existing photovoltaic controller does not consider zero sequence current and voltage, and only injects positive sequence and negative sequence current under unbalanced condition, which injects balanced power to the grid, which can only reduce but cannot eliminate the double fundamental frequency oscillation in the injected active power and reactive power to the network, at the same time, it causes large switching loss, long time and low conversion efficiency of multi-level power switch.

[0007] 5. With the large-scale access of photovoltaic power generation renewable energy to the existing smart grid, numerous controllers are isolated, information is islanded (information does not flow and intercommunicate on the supply side and demand side), and its true value is not reflected, which increases the generation of many current harmonics and the instability of the grid, and the use amount and cost of current, voltage and power detection sensors are large, which pollutes the clean grid. The generation and power quality management and the user side cost scheduling, demand side management and non-intrusive load monitoring become islands, information does not flow in real time, seriously affects the balance between supply and demand, financial and energy efficiency and energy supply and demand, and may cause significant losses to public utility companies, therefore, the end user will generate a high energy consumption bill.

[0008] 6. The existing DDSRF-PLL+PI phase-locked loop has long calculation time under grid voltage imbalance and mixed multiple harmonics, and cannot effectively lock the fundamental voltage, frequency and amplitude of the smart grid, the existing photovoltaic controller generally adopts PI control, PQ control and droop control, all of which adopt long-time calculation algorithm, and cannot provide optimal gain compensation, under the limitation, the feedforward and feedback provide compensation current, reactive power and voltage control action to generate inverter switching pulse, which is inconsistent with the actual inverter switching pulse, cannot realize instant online linear control, and wastes power consumption and inverter efficiency. It is difficult to deal with three-phase unbalanced fault, harmonic, intermittent wave and dynamic random impact load, which seriously affects the conversion quality and efficiency of the converter, as well as the quality of metering and monitoring, and the safe operation of the grid. SUMMARY

[0009] The embodiment of the present application aims to provide a GA-SVM modulation-based Internet of Things photovoltaic power generation energy control system and control method to solve the problems of power imbalance, voltage distribution disorder and imbalance failure, voltage sudden drop and power oscillation at the public coupling point of the current smart grid; the existing smart grid many voltage and current sensors and electronic choke coils are damaged by the power when the non-linear load is applied to the system, the power current tends to be non-sinusoidal and has significant harmonic content loss, the existing PI control, PQ control and droop control take a long time, the power generation system has low power generation efficiency and high power consumption, and the existing electric meter, Internet of Things and smart grid island connection.

[0010] Another purpose of the embodiment of the present application is to provide a smart grid power generation and consumption metering monitoring controller.

[0011] The first technical solution adopted by the embodiment of the present application is a GA-SVM modulation-based Internet of Things photovoltaic power generation control system, comprising:

[0012] A second current modulation module modulates the direct current voltage V dc and the public point three-phase voltage V pcc of the power grid based on a genetic algorithm, and outputs a second reference current

[0013] A voltage conversion module is used to convert the second reference current to obtain voltages V a , V b and V0.

[0014] An SVM wave generation module is used to generate a vector wave according to the input voltages V a , V b and V0.

[0015] A driving circuit is used to drive each switching module of the photovoltaic inverter according to the signal of the SVM wave generation module to control the inverter inversion.

[0016] Further, the second current modulation module comprises:

[0017] A double-synchronous decoupling coordinate system phase-locked loop is used to phase-lock the input public point three-phase voltage V pcc of the power grid and convert it into its equivalent synchronous dq reference system, and output positive and negative sequence voltages and +ωt, -ωt.

[0018] A genetic algorithm module adopts a genetic algorithm to search for an optimal decision variable k value, and the optimal decision variable k value corresponds to a group of reference current values that are optimal for the corresponding unbalanced voltage value and power requirement at the public point of the power grid.

[0019] The reference power generation module is used to generate a DC reference voltage V obtained through maximum power point tracking. dc * DC voltage V dc The reference power P is obtained. * ;

[0020] The reference current generation module is used to generate the reference current based on the optimal decision variable k value and the reference power P. * The positive and negative sequence voltages output by the phase-locked loop in the dual synchronous decoupled coordinate system The conversion is performed to obtain the positive and negative sequence reference currents.

[0021] The second dq0 / αβ0 transformation module is used to transform the positive and negative sequence reference currents according to +ωt and -ωt. The second reference current is obtained by performing a dq / αβ coordinate transformation.

[0022] Furthermore, the reference power generation module includes:

[0023] The first comparator is used to compare the DC reference voltage V. dc * and DC voltage V dc Compare;

[0024] The third PI controller is used to perform proportional-integral calculations on the output voltage of the first comparator, and its transfer function is: It is the proportional gain, K iDC It is integral gain;

[0025] The second comparator is used to compare the output voltage of the third PI controller with the DC voltage V. dc Compare the two and output the maximum value.

[0026] The theoretical power calculation module is used to determine the maximum value of the active power ripple at the inverter output terminal, and to take the active power corresponding to the maximum value of the active power ripple at the inverter output terminal as the theoretical power.

[0027] The third comparator compares the power generated by the maximum voltage output of the second comparator, the theoretical power, and the DC power P. The comparison result is used as the reference power P. * .

[0028] Furthermore, the voltage conversion module includes:

[0029] The abc / αβ conversion module is used to convert the input three-phase current I at the power grid common point. pcc Perform an abc / αβ transformation to output the actual positive and negative sequence currents.

[0030] a second reference current decomposition module, configured to perform positive and negative sequence decomposition on the second reference current to obtain a positive sequence reference current and a negative sequence reference current

[0031] a first synthesized current i α generation module, configured to superimpose the positive sequence reference current the negative sequence actual current and the negative sequence reference current to generate the first synthesized current i α ;

[0032] a second synthesized current i β generation module, configured to superimpose the positive sequence reference current the negative sequence actual current and the negative sequence reference current to generate the second synthesized current i β ;

[0033] a fourth comparator, configured to compare the second reference current with the first synthesized current i α , and output a current value that is most consistent with a current control mode; the current control mode refers to constant active power control, complementary constant active power control and balanced negative sequence reactive power control, balanced positive sequence active power control, complementary constant reactive power control and balanced positive sequence active power control, or constant reactive power control;

[0034] a fifth comparator, configured to compare the second reference current with the second synthesized current i β , and output a current value that is most consistent with a current control mode;

[0035] a first PR controller, configured to perform proportional-resonant control on the output current of the fourth comparator, and output a voltage V a , V0;

[0036] a second PR controller, configured to perform proportional-resonant control on the output current of the fifth comparator, and output a voltage V b , V0;

[0037] a first notch filter, configured to filter the output voltage of the first PR controller;

[0038] a second notch filter, configured to filter the output voltage of the second PR controller.

[0039] Further, the Internet of Things photovoltaic power generation control system based on GA-SVM modulation further comprises:

[0040] a first current modulation module, configured to modulate three-phase currents I a , b , c at an inverter output end and output a first reference current I α2 , β2 , 03 ;

[0041] a competition control module, configured to determine response speeds of the first current modulation module and the second current modulation module, and then perform corresponding switching to enable a connection line between the first current modulation module or the second current modulation module with a faster response speed and the SVM wave generation module, and to disable a connection line between the first current modulation module or the second current modulation module with a slower response speed and the SVM wave generation module; if the response speeds of the first current modulation module and the second current modulation module are equal, the competition control module performs corresponding switching to enable the connection line between the first current modulation module and the SVM wave generation module, and to disable the connection line between the second current modulation module and the SVM wave generation module;

[0042] an αβ0 / abc conversion module, configured to convert the first reference current I α2 , β2 , 03 transmitted by the competition control module into a voltage V a , b , V0when the first current modulation module has a faster response speed.

[0043] Further, the first current modulation module comprises:

[0044] a current feedback device, an input of the current feedback device being the three-phase currents I a , b , c , configured to eliminate errors caused by transmission cables / optical cables;

[0045] a zero-order holder, an input of the zero-order holder being an output of the current feedback device, configured to convert each phase of the three-phase currents I a , b , c from a pulse type into a continuous step signal;

[0046] a positive and negative sequence decomposition module, configured to perform positive and negative sequence decomposition on each phase of the output current of the zero-order holder, and output a positive sequence component and a negative sequence component of each phase of the current;

[0047] a first programmable gain amplifier PGA, an input of the first programmable gain amplifier PGA being the positive sequence component and the negative sequence component of each phase of the current output by the positive and negative sequence decomposition module, configured to perform gain compensation on the input;

[0048] The proportional gain block's input is the three-phase current I at the inverter output. a I b I c ;

[0049] A resettable integrator is used to integrate the output current of the proportional gain block;

[0050] The initial phase angle calculation module takes the output of the resettable integrator as its input and outputs the initial phase angle θ of the output voltage of the resettable integrator.

[0051] The abc / αβ0 conversion module is used to perform abc / αβ0 conversion on the three-phase current output by the first programmable gain amplifier (PGA) based on the initial phase angle θ output by the initial phase angle calculation module, and output a DC current I. α1 I β1 and zero-sequence current / neutral current I 01 ;

[0052] The αβ0 / dq0 conversion module is used to convert DC current I α1 I β1 I 01 Perform αβ0 / dq0 conversion to output active current I. d Reactive current I q and zero-sequence current / neutral current I 02 ;

[0053] The first sinusoidal AC scanning block is used to quickly capture the active current I. d The amplitude, phase, and frequency of the first sinusoidal AC scanning block, and the positive terminal of the first sinusoidal AC scanning block connected to the active current I. d The other path is connected to the negative terminal of the grounded AC scanning circuit. An AC scanning circuit probe is connected between the positive terminal and the output terminal of the first sinusoidal AC scanning block. The AC scanning circuit probe is used to scan the grounded AC scanning circuit to ensure that the scanning of the first sinusoidal AC scanning block is not interrupted.

[0054] The negative terminal of the second sinusoidal AC scanning block is connected to the output of the first sinusoidal AC scanning block, and the positive terminal of the second sinusoidal AC scanning block is connected to the three-phase V. a2 The power factor setting module, with its second sinusoidal AC scanning block used to remove active current I... d microwave, three-phase V a2 The power factor setting module is used to set the three-phase V a2 Power factor, three-phase V a2 Power factor is used to detect active current I. d Is it effective?

[0055] The first PI controller is used to perform proportional-integral control on the output current of the second sinusoidal AC scanning block.

[0056] The third sinusoidal AC scanning block is used to quickly capture reactive current I. q The amplitude, phase, and frequency of the third sinusoidal AC scanning block, and the reactive current I input at the negative terminal. q The positive terminal of the third sinusoidal AC scanning block is connected to the three-phase V. a1 Power factor setting module, three-phase V a1 The power factor setting module is used to set the three-phase V a1 Power factor, three-phase V a1 Power factor is used to detect reactive current I. q Is it effective?

[0057] The second PI controller is used to perform proportional-integral control on the output current of the third sinusoidal AC scanning block.

[0058] The first dq0 / αβ0 transform module, the I of the dq0 / αβ0 transform module d The output of the first PI controller is terminated, and the I of the dq0 / αβ0 conversion module is... q The output of the second PI controller is connected to the terminal, and the zero-sequence current I is connected to the terminal of the dq0 / αβ0 conversion module. 02 The initial phase angle θ and the dq0 / αβ0 transformation module are used to perform dq0 / αβ0 transformation on the input current based on θ, and output the first reference current I. α2 I β2 I 03 .

[0059] The second technical solution adopted in this embodiment of the invention is: an IoT photovoltaic power generation control method based on GA-SVM modulation, which uses the IoT photovoltaic power generation control system based on GA-SVM modulation as described above, and is carried out according to the following steps:

[0060] Step S1: Set the parameters for the first current modulation module, the second current modulation module, the PR controller, and the notch filter;

[0061] Step S2: Receive the three-phase voltage Vpcc and the three-phase current I at the smart grid common point. pcc The three-phase current I at the inverter output terminal a I b I c And the DC output voltage V of the photovoltaic cell dc ;

[0062] Step S3: Real-time acquisition and determination of whether the first reference current I is generated. α2 I β2 I03 and / or the second reference current according to the response speed of the first reference current I α2 , I β2 , I 03 and the second reference current , the response speed of the second current modulation module is optimal; if the second current modulation module is the one with the optimal response speed, the corresponding switching is performed to make the connection line between the second current modulation module and the SVM wave generation module open, while the connection line between the first current modulation module and the SVM wave generation module is closed, and step S5 is entered, otherwise, step S4 is entered;

[0063] Step S4, αβ0 / abc transformation is performed on the first reference current I α2 , I β2 , I 03 to obtain the voltage V a , V b , V0.

[0064] Step S5, the second reference current is compared with the first synthesized current i α , and the optimal output of the comparison is converted into the voltage V a , V0in sequence through the proportional-resonant controller; the second reference current is compared with the second synthesized current i β , and the optimal output of the comparison is converted into the voltage V b , V0in sequence through the proportional-resonant controller; and then the voltage V a , V b , V0is subjected to notch filtering through a notch filter.

[0065] Step S6, according to the voltage V a , V b , V0output by step S4 or the voltage V a , V b , V0output after notch filtering in step S5, the switching module of the drive inverter is controlled based on the SVM wave generation.

[0066] Further, the second reference current is generated according to the following steps:

[0067] Step S31, active voltage V d , reactive voltage V q and zero voltage V0are calculated through formula (1) or formula (2), and the active voltage V d , the reactive voltage V q and the zero voltage V0are subjected to positive and negative sequence decomposition to obtain

[0068] When the q-axis leads the d-axis:

[0069]

[0070] When the q-axis lags behind the d-axis:

[0071]

[0072] in, Phase A V a The phase angle;

[0073] Step S32: Under the constraint of DC bus voltage fluctuation ΔV, the decision variable k is defined by formula (3), and the fitness value is calculated based on the genetic algorithm and combined with formula (6) to search for the optimal decision variable k:

[0074]

[0075] Where ω is the angular frequency of the three-phase voltage at the common point of the power grid, V c DC bus capacitor C DC The voltage;

[0076]

[0077] F(k)=K n (ω1f1(k)+ω2f2(k)+ω2f0(k)); (6)

[0078] Where ω1 is the active voltage angular frequency, ω2 is the reactive voltage angular frequency, and f1(k) is the active power oscillation P. rip The active power ripple function is defined by equation (4), and f2(k) is the reactive power oscillation Q. rip The reactive power ripple function defined by equation (5) has priority over the reactive power ripple function f2(k) in terms of active power ripple function f1(k). n It is a parallel connection number, f0(k) is the zero vector value, used to solve the problem of repeated wave generation; k satisfies -1≤k≤+1, and can take any value between -1 and 1;

[0079] Step S33: Take the active power corresponding to the maximum active power ripple at the inverter output as the theoretical power, and apply it to the DC reference voltage V obtained through maximum power point tracking. dc * With DC voltage V dc After comparison, PI control is performed. The power generated by PI control is compared with the theoretical power and the DC power P to obtain the reference power P. * ;

[0080] Step S34, based on the optimal decision variable k and the reference power P * , the positive and negative sequence reference currents The specific process is as follows:

[0081] When k is set to -1, the active power oscillation is eliminated, constant active power control is adopted, and the negative sequence reference current calculated by formula (7) is used for constant active power control :

[0082]

[0083] When -1 < k < 0, complementary constant active power control and balanced negative sequence reactive power control are adopted, and the negative sequence reference current calculated by formula (8) is used for balanced negative sequence reactive power control :

[0084]

[0085] When k is set to 0, only the positive sequence current element is injected into the power grid, because all negative sequence components are eliminated, the positive sequence reference current calculated by formula (9) is used Balanced positive sequence active power control is performed:

[0086]

[0087] When 0 < k < 1, complementary constant reactive power control and balanced positive sequence active power control are adopted, and the positive sequence reference current calculated by formula (9) is used for balanced positive sequence active power control , and the negative sequence reference current calculated by formula (10) is used for constant reactive power control :

[0088]

[0089] When k = 1, the reactive power oscillation is eliminated, and the negative sequence reference current calculated by formula (10) is used Constant reactive power control is performed;

[0090] The reference power P * and the positive and negative sequence voltages are input into the following formula (13) to generate the negative sequence reference current

[0091]

[0092] Step S35, according to +ωt and -ωt, the positive and negative sequence reference currents under different control modes selected according to the value of k dq0 / αβ transformation is performed to generate the second reference current

[0093] The transfer function G of the PR controller PR (S) is:

[0094]

[0095] The transfer function D(S) of the notch filter is:

[0096]

[0097] Wherein, k p is a proportional gain, k i is a resonance gain, S is a Laplace operator, ω c is a system frequency, and ω0 is a reference frequency.

[0098] The third technical scheme adopted by the embodiment of the present application is: an intelligent power grid power generation and consumption metering monitoring controller, comprising:

[0099] The GA-SVM modulation-based Internet of Things photovoltaic power generation control system as described above sends a current limiting, voltage limiting, temperature limiting unit protection signal for controlling the switches of the inverter through an SVM wave sending module, and implements overvoltage, undervoltage, overcurrent and overtemperature protection.

[0100] Further, the intelligent power grid power generation and consumption metering monitoring controller further comprises:

[0101] An electric energy metering module is configured to perform electric energy metering according to three-phase voltages V pcc at the public point detected by a voltage sensor at the public point and three-phase currents I pcc at the public point detected by a current sensor at the public point.

[0102] An Internet of Things parameter electric energy monitoring module is configured to perform Internet of Things parameter and electric energy monitoring, and is connected with a monitoring / computer control device.

[0103] A hardware configuration module of a current conversion power grid is configured to access the Internet of Things, three-phase currents and three currents, and access a microprocessor through an access middleware.

[0104] A bidirectional alternating current component is configured to be connected with the Internet of Things and the intelligent power grid.

[0105] A power generation parameter detection control module is configured to detect output voltages and currents of a direct current system, voltages and currents output by an inverter, a switching temperature of the inverter, and a voltage Vpcc and a current Ipcc at the public point, and to control a harmonic current I 谐 and a reactive current I无 or reactive power Q 无 Real-time undercurrent, no current, power shortage protection

[0106] The driving circuit of the GA-SVM modulation-based Internet of Things photovoltaic power generation control system comprises:

[0107] Pulse minimum compensation limiting module The minimum wave emission delay is used to avoid the GA-SVM modulation-based Internet of Things photovoltaic power generation control system synchronous wave emission of the power generation parameter detection control module when injecting harmonic current, reactive current or reactive power, and the delay time is consistent with the injection time of the harmonic current, the reactive current or the reactive power. The input of each pulse minimum compensation limiting module is the three-phase pulse output by the SVM wave emission module.

[0108] Second programmable gain amplifier PGA, the input of each second programmable gain amplifier PGA is the output signal of the corresponding pulse minimum compensation limiting module , and gain compensation is performed; the output of each second programmable gain amplifier PGA is connected to the driving end of two switch modules of the corresponding bridge arm of the inverter through two gate buffers.

[0109] Each second programmable gain amplifier PGA is connected to a power scan meter in parallel, and the power scan meter is used to judge whether the injection of the harmonic current, the reactive current or the reactive power is completed. When the injection of the harmonic current, the reactive current or the reactive power is completed, the second programmable gain amplifier PGA works in the wave emission process.

[0110] The embodiment of the present application has the following advantages:

[0111] 1. The DDSRF-PLL+PI+genetic algorithm+PR controller+notch filter is adopted, the PR controller solves the problem of voltage sudden rise and sudden drop, the notch filter solves the problem of voltage peak, the voltage peak of the PR controller voltage sudden rise and sudden drop is coupled with the reverse voltage fluctuation peak of the notch filter, the complementary voltage fluctuation peak part, the DDSRF-PLL+PI+genetic algorithm solves the problem of power imbalance and power oscillation, especially the genetic algorithm greatly simplifies the mathematical model, shortens the calculation time, makes the DDSRF-PLL+PI can quickly lock the fundamental voltage frequency and amplitude, and makes the DDSRF-PLL+PI utilize its own advantages to suppress multiple harmonics, power imbalance and power oscillation.

[0112] 2. The PI + scanning control + current pre-gain modulation control route can quickly capture parameters, has high speed and high efficiency, and effectively solves the long time consumption problem of the existing PI control, PQ control and droop control. Both control routes adopt direct current and alternating current current, voltage gain modulation and power control, eliminate the increase of power consumption caused by the healthy voltage and current caused by harmonic current compensation, reactive current and reactive power during fault, reduce the inverter efficiency and voltage fluctuation, and pass through the fault of low voltage and high voltage.

[0113] 3. The SVM is used for voltage vector frequency control, can control the inter-harmonic, has high control accuracy, removes repeated wave emission, effectively reduces power consumption, improves MPPT tracking maximum power beat, can quickly capture maximum voltage, improves power generation efficiency, and effectively solves the low power generation efficiency problem of the current power generation system.

[0114] 4. The mixer and microcontroller are used to integrate the electric meter, Internet of Things and smart grid, can realize real-time communication with the load, ensure the real-time flow of information, ensure the balance between supply and demand, effectively solve the island connection problem of the current electric meter, Internet of Things and smart grid. The original electric energy meter control system and photovoltaic control system are replaced by the mixer + microcontroller + wireless adapter, the use amount of voltage and current sensors and electronic choke coils is reduced, and the harmonic content and loss are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0115] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0116] Figure 1 is a structure diagram of the Internet of Things photovoltaic power generation energy control system based on GA-SVM modulation of the embodiment of the present application.

[0117] Figure 2 is a wave emission waveform diagram of the genetic vector sector sinusoidal basic carrier wave modulation wave emission control inverter of the embodiment of the present application.

[0118] Figure 3(a) is the e i(t) = 0, modulation index m max is the waveform diagram of the modulation index

[0119] Figure 3(b) is the waveform diagram of the modulation index i (t) = 0, modulation index m is the waveform diagram of the modulation index

[0120] Figure 3(c) is the waveform diagram of the modulation index modulation index is the waveform diagram of the modulation index

[0121] Figure 4 is the waveform comparison diagram of the svm injected harmonic current and the three modulation voltage waveforms and the fundamental wave waveform of the embodiment of the present application.

[0122] Figure 5(a) is the waveform diagram of the modulation index is the waveform diagram of the zero vector

[0123] Figure 5(b) is the waveform diagram of the modulation index is the waveform diagram of the zero vector

[0124] Figure 5(c) is the waveform diagram of the modulation index is the waveform diagram of the zero vector

[0125] Figure 6(a) is a different reactive power compensation diagram of the PCC voltage distribution of the genetic vector sector sinusoidal basic carrier wave modulation wave control inverter of the embodiment of the present application.

[0126] Figure 6(b) is a different reactive power compensation diagram of the reactive power provided by the PCC solar inverter of the genetic vector sector sinusoidal basic carrier wave modulation wave control inverter of the embodiment of the present application. DETAILED DESCRIPTION

[0127] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0128] Embodiment 1

[0129] The Internet of Things photovoltaic power generation control system based on GA-SVM modulation of the embodiment of the application, as shown in Figure 1 , comprises:

[0130] The first current modulation module is used for modulating the three-phase current I a , I b , I c sampled by the current sampling 1 at the output end of the inverter, and outputting the first reference current I α2 , I β2 , I 03 The current sampling 1 can adopt a current sensor, and the first current modulation module comprises:

[0131] The current feedback device, the input of the current feedback device is the three-phase current I a , I b , I c , and the output is the input of the zero-order holder ZOH, which is used to eliminate the error caused by the transmission cable / optical cable;

[0132] The zero-order holder ZOH, the input of the zero-order holder ZOH is the output of the current feedback device, and the output of the zero-order holder ZOH is the input of the positive and negative sequence decomposition module, which is used to convert each phase of the three-phase current I a , I b , I c from the pulse type into a continuous step signal, and the sampling frequency of the zero-order holder ZOH can be preferably set to 20KHz;

[0133] The positive and negative sequence decomposition module is used for positive and negative sequence decomposition of each phase of the output current of the zero-order holder, and outputs the positive sequence component and the negative sequence component of each phase current;

[0134] The first programmable gain amplifier PGA, the input of the first programmable gain amplifier PGA is the positive sequence component and the negative sequence component of each phase current output by the positive and negative sequence decomposition module, and the output of the first programmable gain amplifier PGA is the three-phase alternating current input of the abc / αβ0 conversion module, and the first programmable gain amplifier PGA is used for gain compensation;

[0135] The proportional gain block, the input of the proportional gain block is the three-phase current I a , I b , I c at the output end of the inverter, and the output of the proportional gain block is the input of the resettable integrator, and the constant parameter C4 of the proportional gain block can be set to 100, and the gain can be set to 1 / 10;

[0136] The resettable integrator, the input of the resettable integrator is the output of the proportional gain block, and the output voltage is the input of the initial phase angle calculation module, and the s3 gain 86.928m, the time constant 349.983u, the low output limit-1, the output upper limit 1 and the sampling frequency 29k can be set;

[0137] a phase angle calculation module, the input of the phase angle calculation module is the output of the resettable integrator, and the output is an initial phase angle θ of the output voltage of the resettable integrator;

[0138] A voltage detection module is further arranged between the resettable integrator and the initial phase angle calculation module.

[0139] An abc / αβ0 conversion module is arranged for performing abc / αβ0 conversion on the three-phase current output by the first programmable gain amplifier PGA according to the output of the initial phase angle calculation module, and outputting direct current I α1 , I β1 , and zero sequence current / neutral current I 01 .

[0140] An αβ0 / dq0 conversion module is arranged for performing αβ0 / dq0 conversion on the direct current I α1 , I β1 , I 01 , and outputting active current I d , reactive current I q , and zero sequence current / neutral current I 02 ; the waveform of I q when I d =0 is shown in FIG. Figure 2 ;

[0141] A first sinusoidal AC scanning block, the positive electrode of the first sinusoidal AC scanning block is connected to the active current I d , and the other end is connected to the negative electrode of the AC scanning loop grounded, and an AC scanning loop probe is connected between the positive electrode of the first sinusoidal AC scanning block and the output end, the AC scanning loop probe is used to scan the AC scanning loop grounded, to ensure that the scanning of the first sinusoidal AC scanning block is not interrupted; the first sinusoidal AC scanning block is used to quickly capture the amplitude, phase, and frequency of the active current I d , to improve the speed;

[0142] A second sinusoidal AC scanning block, the negative electrode of the second sinusoidal AC scanning block is connected to the output of the first sinusoidal AC scanning block, and the positive electrode of the second sinusoidal AC scanning block is connected to the three-phase V a2 A power factor setting module, the second sinusoidal AC scanning block is used to remove the micro-wave of the active current I d , the three-phase V a2 The power factor setting module is used to set the three-phase V a2 power factor, the three-phase V a2 power factor is initially set to 1, and is set to 5 after initialization, the three-phase V a2 power factor is used to detect whether the active current I d is valid;

[0143] The first PI controller is used for proportional integral control on the output current of the second sinusoidal AC scanning block.

[0144] The third sinusoidal AC scanning block, the negative input of the third sinusoidal AC scanning block is connected with the reactive current I q , the positive terminal of the third sinusoidal AC scanning block is connected with the three-phase V a1 The power factor setting module is used for setting the three-phase V a1 The power factor setting module is used for setting the three-phase V a1 The power factor setting module is used for setting the three-phase V a1 The power factor setting module is used for setting the three-phase V a1 The power factor initial state is set to 0, and after initialization is completed, it is set to 0.5, and the third sinusoidal AC scanning block is used for quickly capturing the amplitude, phase and frequency of the reactive current I q , the three-phase V a1 The power factor setting module is used for setting the three-phase V

[0145] The second PI controller is used for proportional integral control on the output current of the third sinusoidal AC scanning block.

[0146] The first dq0 / alpha beta0 conversion module, the I d terminal of the first PI controller is connected with the output of the first PI controller, the I q terminal of the second PI controller is connected with the output of the second PI controller, the 0 terminal of the dq0 / alpha beta0 conversion module is connected with the zero sequence current I0, and the initial phase angle theta is connected with the dq0 / alpha beta0 conversion module, the dq0 / alpha beta0 conversion module is used for carrying out dq0 / alpha beta0 conversion on the input current according to the theta, and the dq0 / alpha beta0 conversion module is used for outputting the first reference current I α2 , I β2 , I 03 ;

[0147] The output current of the programmable gain amplifier PGA is sequentially subjected to three coordinate transformations, so that the three-phase AC power is converted into a direct current component, and the harmonics in the direct current component are eliminated.

[0148] The GA-SVM modulation-based Internet of Things photovoltaic power generation control system provided by the embodiment of the application further comprises:

[0149] The second current modulation module is used for modulating the direct current voltage V dc sampled by the direct current voltage sampling 1 and the grid public point three-phase voltage Vpcc sampled by the voltage sampling 0 based on a genetic algorithm, and outputting the second reference current The second current modulation module comprises:

[0150] A dual synchronous decoupled frame phase-locked loop (DDSFR-PLL) is used to phase-lock and convert an input three-phase voltage Vpcc into an equivalent synchronous dq reference frame, outputting positive and negative sequence voltages and +ωt, -ωt;

[0151] A genetic algorithm module uses a genetic algorithm to search for an optimal decision variable k value, which corresponds to a set of reference current values for a corresponding unbalanced voltage value and power requirement at a grid point;

[0152] A reference power generation module is used to generate a reference power P dc * from a direct current voltage V dc obtained by maximum power point tracking (MPPT); * The reference power generation module includes:

[0153] A first comparator is used to compare the direct current reference voltage V dc * and the direct current voltage V dc ;

[0154] A third PI controller is used to proportionally and integrally control the output voltage of the first comparator, and the transfer function is is a proportional gain, and K iDC is an integral gain;

[0155] A second comparator is used to compare the output voltage of the third PI controller and the direct current voltage V dc , and output the maximum value of the two;

[0156] A theoretical power calculation module is used to determine the maximum active power ripple at the output end of the inverter, and the active power corresponding to the maximum active power ripple at the output end of the inverter is used as the theoretical power;

[0157] A third comparator is used to compare the maximum value of the output voltage of the second comparator, the theoretical power, and the direct current power P * ;

[0158] A reference current generation module is used to convert the positive and negative sequence voltages output by the dual synchronous decoupled frame phase-locked loop (DDSFR-PLL) according to the optimal decision variable k value and the reference power P * , to obtain the positive and negative sequence reference currents in the positive and negative sequence reference currents ; Figure 1 ;

[0159] ​The second dq0 / αβ0 transformation module is used to transform the positive and negative sequence reference currents according to +ωt and -ωt. Perform a dq / αβ coordinate transformation to obtain the second reference current.

[0160] The IoT photovoltaic power generation control system based on GA-SVM modulation according to embodiments of the present invention further includes:

[0161] The competition control module is used to determine the response speed of the first current modulation module and the second current modulation module, and then switch accordingly to connect the connection line between the first current modulation module and the SVM waveform transmission module with the fastest response speed, while closing the connection line between the first current modulation module and the SVM waveform transmission module with the slowest response speed.

[0162] If the first current modulation module has the best response speed, then the first current modulation module outputs the first reference current I before the second current modulation module. α2 I β2 At this point, the competition control module switches accordingly, connecting the first current modulation module and the SVM waveform generation module, while simultaneously closing the connection between the second current modulation module and the SVM waveform generation module. If the second current modulation module has the best response speed, it outputs the second reference current before the first current modulation module. At this time, the competition control module switches accordingly to connect the connection line between the second current modulation module and the SVM wave generation module, while simultaneously closing the connection line between the first current modulation module and the SVM wave generation module.

[0163] The IoT photovoltaic power generation control system based on GA-SVM modulation according to embodiments of the present invention further includes:

[0164] When the second current modulation module has the best response speed, the voltage conversion module is used to adjust the second reference current transmitted by the contention control module. The voltage V is obtained by conversion a V b V0, the voltage conversion module includes:

[0165] The abc / αβ conversion module is used to perform abc / αβ conversion on the input three-phase current Ipcc at the power grid common point, and output positive and negative sequence currents.

[0166] The second reference current decomposition module is used to decompose the second reference current. Perform positive and negative sequence decomposition to obtain the positive sequence reference current. and negative sequence reference current

[0167] first resultant current i α a generating module for superimposing the positive sequence reference current negative sequence current and to generate the first resultant current i α ;

[0168] second resultant current i β a generating module for superimposing the positive sequence reference current negative sequence current and to generate the second resultant current i β ;

[0169] a fourth comparator for comparing the second reference current with the first resultant current i α , and outputting a current value most consistent with the current control mode; the current control mode refers to constant active power control, complementary constant active power control and balanced negative sequence reactive power control, balanced positive sequence active power control, complementary constant reactive power control and balanced positive sequence active power control, or constant reactive power control;

[0170] a fifth comparator for comparing the second reference current with the second resultant current i β , and outputting a current value most consistent with the current control mode;

[0171] a first PR controller for performing proportional-resonant control on the output current of the fourth comparator, and outputting voltages V a and V0;

[0172] a second PR controller for performing proportional-resonant control on the output current of the fifth comparator, and outputting voltages V b and V0.

[0173] The Internet of Things photovoltaic power generation control system based on GA-SVM modulation of the embodiment of the application further comprises:

[0174] a first notch filter for filtering the output voltage of the first PR controller;

[0175] a second notch filter for filtering the output voltage of the second PR controller.

[0176] The Internet of Things photovoltaic power generation control system based on GA-SVM modulation of the embodiment of the application further comprises:

[0177] a β 0 / abc conversion module, when the first current modulation module is the optimal response speed, the a β 0 / abc conversion module is used to convert the first reference current I α2 β2 a b

[0178] The GA-SVM modulation-based Internet of Things photovoltaic power generation control system of the embodiment further includes:

[0179] An SVM (space vector modulation) wave emitting module, which is used to emit a vector wave according to an input voltage;

[0180] A driving circuit, which is used to drive each switching module of the inverter according to a signal of the SVM wave emitting module to control the inverter to invert, and includes:

[0181] A pulse minimum compensation limiting module which is used to perform minimum wave emitting delay to avoid synchronous wave emission when harmonic current, reactive current or reactive power injection is performed, and the delay time is consistent with the harmonic current, reactive current or reactive power injection time, the input of each pulse minimum compensation limiting module is three-phase pulses output by the SVM wave emitting module, and the output enters a second programmable gain amplifier PGA;

[0182] The second programmable gain amplifier PGA, the input of each second programmable gain amplifier PGA is an output signal of the corresponding pulse minimum compensation limiting module , and the output is connected to the driving end of two switching modules of the corresponding bridge arm of the inverter through two gate buffer circuits. Each second programmable gain amplifier PGA programmable gain amplifier PGA is provided with a power scan meter, which is used to determine whether injection is completed, when the injection is completed, the first programmable gain amplifier PGA works to enter the wave emitting process, and the function of the power scan meter is completed by software.

[0183] The functions of the smart grid power generation and consumption metering monitoring controller and the GA-SVM modulation-based Internet of Things photovoltaic power generation control system are realized by a mixed signal controller and a microprocessor, and the mixed signal controller, the microprocessor and the power generation system communicate with each other through a serial port.

[0184] The output end of the driving circuit is 3×n, which is connected to the control pole of the n×6 switching of the inverter bridge arm through a 6×n gate buffer, and n≥1, wherein n represents the number of parallel inverters.

[0185] Embodiment 2

[0186] ​​​​The embodiment of the present application provides a kind of GA-SVM modulation-based control method for photovoltaic power generation of Internet of Things, using the GA-SVM modulation-based control system for photovoltaic power generation of Internet of Things described in embodiment 2, according to the following steps:

[0187] Step S1, parameter setting is carried out to the first current modulation module, the second current modulation module, the PR controller and the wave trap filter;

[0188] Step S2, receiving three-phase voltage V pcc At the public point of smart grid, pcc Three-phase current I a At the output end of inverter, b I c , and photovoltaic cell direct-current output voltage V dc ;

[0189] Step S3, real-time acquisition and judgment are carried out to whether first reference current I α2 I β2 I 03 And / or second reference current According to the response speed of first reference current I α2 I β2 I 03 And second reference current , the response speed of the optimal one in the first current modulation module and the second current modulation module is determined;If the first current modulation module is the optimal one in response speed, corresponding switching is carried out to make the connection line between the first current modulation module and the SVM wave module be connected, while the connection line between the second current modulation module and the SVM wave module is closed, and step S4 is entered;If the second current modulation module is the optimal one in response speed, corresponding switching is carried out to make the connection line between the second current modulation module and the SVM wave module be connected, while the connection line between the first current modulation module and the SVM wave module is closed, and step S5 is entered;

[0190] Second reference current According to the following steps is generated:

[0191] Step S31, active voltage V d , reactive voltage V q And zero voltage V0 are calculated by formula (1) or formula (2), and active voltage V d , reactive voltage V q And zero voltage V0 are carried out positive and negative sequence decomposition, and

[0192] When q-axis is ahead of d-axis:

[0193]

[0194] When the q-axis lags the d-axis:

[0195]

[0196] wherein, is the phase angle of the A-phase V a ;

[0197] Step S32, under the DC bus voltage fluctuation ΔV limit, the decision variable k is defined by formula (3), the fitness value is calculated based on the genetic algorithm combined with formula (6), and the optimal decision variable k is searched:

[0198]

[0199] wherein, ω is the angular frequency of the three-phase voltage at the grid common point, V c is the voltage of the DC bus capacitor C DC ;

[0200]

[0201] F(k)=K n (ω1f1(k)+ω2f2(k)+ω2f0(k)); (6)

[0202] wherein, ω1 is the active voltage angular frequency, ω2 is the reactive voltage angular frequency, f1(k) is the active power ripple P rip defined by equation (4), f2(k) is the reactive power ripple Q rip defined by equation (5), the active power ripple function f1(k) is prior to the reactive power ripple function f2(k), K n is the parallel connection coefficient, f0(k) is the zero vector value, used to solve the problem of repeated wave emission; k satisfies -1≤k≤+1, taking any value between -1 and 1;

[0203] Step S33, the active power corresponding to the maximum active power ripple of the inverter output end is taken as the theoretical power, and the DC reference voltage V dc * is compared with the DC voltage V dc , and then PI control is performed, the power generated by PI control is compared with the theoretical power and the DC power P to obtain the reference power P * ;

[0204] Step S34, based on the optimal decision variable k and the reference power P * , the current is calculated. The specific process is as follows:

[0205] k is set to -1, the active power oscillation is eliminated, constant active power control is adopted, in order not to affect the positive sequence current, the constant active power control adopts the negative sequence reference current calculated by formula (7) Carry out:

[0206]

[0207] -1 < k < 0, complementary constant active power control and balanced negative sequence reactive power control are adopted, the balanced negative sequence reactive power control adopts the negative sequence reference current calculated by formula (8) Carry out:

[0208]

[0209] k is set to 0, only the positive sequence current element is injected into the power grid, because all negative sequence components are eliminated, the positive sequence reference current calculated by formula (9) is adopted Carry out balanced positive sequence active power control:

[0210]

[0211] 0 < k < 1, complementary constant reactive power control and balanced positive sequence active power control are adopted, the balanced positive sequence active power control adopts the positive sequence reference current calculated by formula (9) Carry out, the constant reactive power control adopts the negative sequence reference current calculated by formula (10) Carry out:

[0212]

[0213] k = 1 eliminates the reactive power oscillation, the negative sequence reference current calculated by formula (10) is adopted Carry out constant reactive power control;

[0214] In the feasible range (-1 ≤ k ≤ 1), the active power oscillation P rip Satisfies formula (11):

[0215]

[0216] In the feasible range (-1 ≤ k ≤ 1), the reactive power oscillation Q rip Satisfies formula (12):

[0217]

[0218] The reference power P * And the positive and negative sequence voltages Input to the following formula (13) to generate the negative sequence reference current

[0219]

[0220] Constant active power control (CAPC), balanced negative sequence reactive power control, balanced positive sequence active power control (BPSC), constant reactive power control are input by I / O port of hybrid signal controller +ωt, -ωt, optimal k value, reference power P * , MCU calculates positive and negative sequence reference currents i d +* , i q +* , i d -* , i q -* , i0 * .

[0221] The hybrid signal controller selects the chip MSP4306764A. According to the required control mode, the selection of these control targets may cause the controller (GA-SVM modulation-based Internet of Things photovoltaic power generation energy control system) to inject unbalanced three-phase current into the power grid, and at the same time, the micro control processor (TM4C129XKCZAD) of the hybrid signal controller sends a current limiting, voltage limiting, and temperature limiting unit protection signal to control the switching of the three-phase inverter bridge (inverter) through the SVM wave module, and implements overvoltage, undervoltage, overcurrent, and overtemperature protection; At the same time, for undercurrent or no current, power deficiency, through the multi-bit switch connected with the hybrid signal controller, the corresponding harmonic compensation current I 谐 , reactive compensation current I 无 , and reactive compensation power Q 无 are injected into the power grid, so that the inverter prevents the controller (GA-SVM modulation-based Internet of Things photovoltaic power generation energy control system) from tripping due to overcurrent; For grid-connected inverters operating under unbalanced voltage, the percentage limit of the DC bus voltage ripple relative to the required average voltage level and the maximum value of the reference voltage limits the optimal k value of the search genetic algorithm, and the inverter bridge switches under safe voltage, temperature, and current, preventing the inverter bridge from burning out and reducing its lifespan and efficiency, while preventing smooth switching of smart grids and renewable energy sources, ensuring reliable power supply; Preventing losses caused by photovoltaic off-grid; At the same time, it ensures the synchronous operation of the power consumption side, photovoltaic power supply, and smart grid, reliable operation and switching of multiple operation modes, and achieves photovoltaic power generation balanced grid smart grid;

[0222] Step S35, according to +ωt, -ωt, the positive and negative sequence reference currents under different control modes selected according to the k value dq0 / αβ transformation is performed to generate the second reference current

[0223] Step S4, αβ0 / abc transformation is performed on the first reference current I α2 , β2 , I0to obtain the voltage V a , V b , V0;

[0224] Step S5, the second reference current I is compared with the first synthesized current i α , and the optimal output of the comparison is converted into the voltage V a , V0in sequence through a proportional-resonant controller; the second reference current I is compared with the second synthesized current i β , and the optimal output of the comparison is converted into the voltage V b , V0in sequence through a proportional-resonant controller; and the voltage V a , V b , V0is notch filtered through a notch filter;

[0225] The transfer function G PR (S) of the proportional-resonant (PR) controller is:

[0226]

[0227] wherein k p is a proportional gain, k i is a resonant gain, S is a Laplace operator, ω c is a system frequency, and ω0is a reference frequency;

[0228] The transfer function D(S) of the notch filter is:

[0229]

[0230] The harmonic filter processing calculated through the Laplace operator, gain, and frequency in formula (13) processes the sinusoidal signals generated by each harmonic and the elimination of steady-state error, and inputs the sinusoidal signals into the notch controller, which is processed through the notch transfer function in formula (14), so that D(s) generates a negative resonant peak at ω0, eliminates the positive resonant peak at ω0, and generates the voltage values V a , V b , and zero voltage V0;

[0231] Step S6, based on the voltage V a , V b , V0output by step S4 or the voltage V a , V b , V0output after notch filtering in step S5, a switching module of a driving inverter is controlled based on SVM (space vector modulation), and the specific process is as follows:

[0232] like Figure 1 The 6 switches shown vector state With zero order and Input vector space SVPWM, modulation signal u of three-phase carrier SVPWM modulator i The DC bus voltage of (t)(i=a,b,c) is E, using zero sequence... and Injecting harmonics e i (t) is called the zero-sequence signal; T S It is the sampling time, T S Voltage vector U S The sampling interval time, its reciprocal Sampling frequency; voltage vector U S Set on the axis of the space vector, and Corresponding overlap (6 switches) and (Vector signal correspondence), first calculate the zero sequence e of sectors 1 to 6 according to Table 2. i (t) and T S Then T S Substituting the values ​​from Table 1 into the space vector modulation algorithm, we can calculate the corresponding modulation for sectors 1 to 6. The transmission times T1, T2, T3, T4, T5, T6, T7, and T0 are calculated. Then, T1, T2, T3, T4, T5, T6, T7, and T0 are substituted into Table 3 to calculate the basic signal and space vector. Next, based on the space vector and basic signal, the space vector sector and fundamental modulation signal are calculated into Table 4. Finally, the space vector sector and fundamental modulation signal are substituted into Table 5, and the vector switch... Based on the switching states, the switching states in Table 6 are obtained. The switch status and switch code are determined, and then, according to the switch code, the sequential wave drive of serial numbers 1 to 8 in Table 6 is sent sequentially to drive the inverter bridge, lock the grid voltage, synchronize clean power generation, and inject it into the grid.

[0233] Table 1 Space Vector Modulation Algorithm

[0234]

[0235] Table 2 Zero-order e i (t) and space vector to calculate space voltage vector T S

[0236]

[0237]

[0238] Table 3 Fundamental signals and space vector calculation

[0239]

[0240] Table 4 Space vector sector and fundamental modulation signal calculation

[0241]

[0242] Table 5 Vector switch, line voltage and space vector relationship

[0243]

[0244]

[0245] Table 6 Vector switch state and switch code

[0246]

[0247] The metering chip of electric energy, i.e. the mixed signal controller MSA430F67641A, according to the space vector modulation algorithm of Table 1, when the input voltage is a sine wave, the zero sequence e i (t) is set to 0; when an unbalanced fault is encountered, i.e. the input voltage is an abnormal sine wave, the zero sequence e and harmonic e i (t) is injected, the modulation signal is the sum of the fundamental signal and the injected harmonic, as shown in formula (15), and the injected harmonic does not appear in the line voltage of Table 5. The line voltage, vector switch state and space vector are shown in Table 5.

[0248] Modulation signal u i (t) (i = a, b, c) is as follows:

[0249]

[0250] wherein e i (t) is the injected harmonic, called the fundamental signal, is a three-phase symmetrical sine signal, as shown in formula (17):

[0251]

[0252] wherein m is the modulation index, and u i (t), i = a, b, c, according to (16) and (17), the output line to zero line voltage:

[0253]

[0254] Output line voltage Vab , V bc and V ca are:

[0255]

[0256] In the linear modulation range, equations (18), (19) and |u i (t)|≤1, i = a, b, c indicate that the output line-to-line voltage is equal to or less than the DC bus voltage E, therefore, the possible maximum modulation index is In the linear range, the zero sequence signal calculation formula is:

[0257]

[0258] e i (t) = 0, a sine wave is generated, in the linear range, |u i (t)|≤1, i = a, b, c, m max = 1 sine wave-based SVPWM modulation signal is shown in Figure 3(a); and the maximum output line-to-line voltage is

[0259] When m > 1, overmodulation occurs, in the linear range, there is the formula:

[0260]

[0261] In combination with Table 2 zero sequence ei(t) and space vector calculation space voltage vector TS, based on the equivalent switching mode of discontinuous DPWM of double-edge wave, e i (t) can be expressed as: When the genetic vector sector sine wave fundamental carrier modulation firing control inverter, the zero vector waveform diagram of the firing is shown in Figure 5(a); for When the genetic vector sector sine wave fundamental carrier modulation firing control inverter, the zero vector waveform diagram of the firing is shown in Figure 5(b); for When the genetic vector sector sine wave fundamental carrier modulation firing control inverter, the zero vector waveform diagram of the firing is shown in Figure 5(c).

[0262] When e i (t) is a suitable signal, such as The maximum modulation index three harmonic injection is shown in Figure 3(b), e i (t)≠0, a non-sine SVPWM appears, in the linear modulation range with the maximum modulation index is shown in Figure 3(c).

[0263] The basic signal in the (a, b, c) plane and the active vector in the (α, β) plane are pushed as follows:

[0264]

[0265] where T α and T β are the inverse matrix of T the corresponding components in the two-phase stationary coordinate system obtained by the 3 / 2 transformation, the inverse matrix of T β , the inverse matrix of T S ;

[0266]

[0267] Equations (23) and (24) are the 3 / 2 transformation and 2 / 3 transformation respectively. Due to the same space sector measurement, the above transformation can be inclined to all other five sectors, in terms of switching characteristics, the SVPWM scheme can be divided into continuous SVPWM in linear modulation range and discontinuous SVPWM. Therefore, during each carrier signal, each output of the converter branch is in the positive and negative sequence of the DC link, while for discontinuous, in each carrier cycle, one modulation signal will be equal to "±1", and the corresponding branch is connected to the positive or negative sequence link of the DC without switching action. Therefore, from Figure 2 Fig. 3(a), Fig. 3(b), Fig. 3(c), Figure 4 Fig. 5(a), Fig. 5(b), Fig. 5(c), compared with the continuous SVPWM scheme, the discontinuous SVPWM scheme can reduce the average switching frequency by 33% and the unnecessary switching loss. The relationship between the modulation signal and the space vector sector modulation signal is obtained by formula (23) and formula (24). The space vector sector is as shown in Figure 1 .

[0268] Figure 1 There are eight switching states in the vector diagram of The output voltage of the inverter is composed of these 8 switching states. Define 8 voltage vectors corresponding to these 8 switching states Switching state corresponding The length of 1, and The length of 0. These 8 vectors constitute a voltage vector space, which is divided into 6 sectors. According to the equivalence principle, formula (25) is obtained:

[0269]

[0270] Let The length of m*E, there is:

[0271]

[0272] m * is the modulation index, is the phase angle, T1 is the starting boundary time of each sector, and T2 is the ending boundary time of each sector;

[0273] In a sampling interval T S , the output voltage vector is calculated by formula (27):

[0274]

[0275] where t0-t7 are the opening times of the voltage vector corresponding to the sampling time, t0-t7≥0. According to formula (24) and (26),

[0276] is decomposed into In a limited manner, in order to reduce the number of switching actions, the active conduction time of the space vector is fully utilized, and the vector is usually split into two nearest adjacent voltage vectors and The zero vector and the n arbitrary sector switching drive action function meet table 3 and formula (28):

[0277] The SVM output Vma and the SWa, SWb, SWc three-phase frequency, Vma is set after the SVPWM AC scanning probe (loop), the running time graphical window displays Id, Iq, and the delay block 1 / Z is set after the setting, which mainly limits the minimum period, and it will drive the minimum time step. After the delay block 1 / Z, the PGA is set, the PGA is led out of the power scanning meter; two gate buffers are led out after the PGA; the first one is a gate buffer, which corresponds to the on-off of the upper switch

[0278] of the inverter; the second one is a gate buffer in series, which corresponds to the on-off of the lower switch of the inverter.

[0279] Figure 1 All possible conversion switching states between different types are shown, and each arrow represents a switching action, for example, the conversion from to requires at least one switching action, and the conversion from to requires at least three switching actions, which indicates the switching mode of the space vector modulation. When the vector switching state is 1, the switching state is 111, the upper switch is opened, and the lower switch​ off; when the vector switch state is 0, the switch state is 000, the lower switch opening action, upper switch off. When encountering unbalanced fault, low voltage fault, zero sequence injection modulation index is 0~0.5, e i (t), the voltage bottom of driving photovoltaic power switch is raised and the top value is raised to the peak of modulation index 1, see figure 5. Inject zero sequence current, calculate zero sequence vector, get 6 sector space voltage vector T S Then T S is brought into the space vector modulation algorithm in table 1 to obtain the modulation times of 6 space vectors; calculate the basic signal according to table 3, and then calculate the fundamental modulation basic signal according to table 4, the sinusoidal curve is obtained by the signal of the fundamental modulation basic signal + vector 0 and vector 7, the switch code is obtained, and the corresponding frequency is emitted according to the switch code; the abnormal sinusoidal curve is obtained by the signal of the fundamental modulation basic signal + vector 0 and vector 7 + e i (t) signal superposition formed voltage waveform emission, driving the upper switch of the inverter Or lower switch Synchronization press Figure 4 The waveform shown runs.

[0280] Specific SVM emission: according to Figure 1 The inverter bridge is composed of 6 IGBT / IGCT intelligent switch modules, and the 6 switches are distributed in 6 sectors in SVM, and the 6 sectors are defined by voltage vectors as boundary values; wherein is the origin, i.e. zero voltage vector, and the 6 sectors are equally divided by 60°, and each 60° sector is further divided into 30°; as shown in figures 3, 5, tables 1-6, the switch frequency, switch state and space vector of the vector switch in SVM are defined as follows:

[0281] Vector switch Switch state: 100; vector 30°; space voltage vector: T s =T1+T2+T0+T7; zero sequence e i (t): Corresponding sector Vector modulation algorithm: T0+T7=T s -T1-T2; basic signal and space vector: Fundamental adjustment signal:

[0282] Vector switch Switch state: 010; vector 90°; space voltage vector: T s= T2+T3+T0+T7; zero sequence e i (t): corresponding sector vector modulation algorithm: T0+T7=T s -T2-T3; basic signals and space vectors: fundamental adjustment signal:

[0283] vector switch switch state: 110; vector 150°; space voltage vector: T s = T3+T4+T0+T7; zero sequence e i (t): corresponding sector vector modulation algorithm: T0+T7=T s -T3-T4; basic signals and space vectors: fundamental adjustment signal:

[0284] vector switch switch state: 011; vector 210°; space voltage vector: T s = T4+T5+T0+T7; zero sequence e i (t): corresponding sector vector modulation algorithm: T0+T7=T s -T4-T5; basic signals and space vectors: fundamental adjustment signal:

[0285] vector switch switch state: 001; vector 270°; space voltage vector: T s = T5+T6+T0+T7; zero sequence e i (t): corresponding sector vector modulation algorithm: T0+T7=T s -T5-T6; basic signals and space vectors: fundamental adjustment signal:

[0286] vector switch switch state: 101; vector 360°; space voltage vector: T s = T6+T1+T0+T7: zero sequence e i (t): corresponding sector Vector modulation algorithm: T0+T7=T s -T5-T6; basic signal and space vector: Fundamental adjustment signal:

[0287] Vector switch Switch state: 000; vector 0°;

[0288] Vector switch Switch state: 111; vector 0°.

[0289] 6 sectors of space vector SVM drive GM-SVM vector switch state and switch code definition:

[0290] Switch state: Corresponding switch code: 100;

[0291] Switch state: Corresponding switch code: 110;

[0292] Switch state: Corresponding switch code: 010;

[0293] Switch state: Corresponding switch code: 011;

[0294] Switch state: Corresponding switch code: 001;

[0295] Switch state: Corresponding switch code: 101;

[0296] Switch state: Corresponding switch code: 111;

[0297] Switch state: Corresponding switch code: 000.

[0298] Experimental results:

[0299] The experimental platform includes a set of inverter board, three-phase LCL filter, three-phase network inductance, current and voltage sensor, three-phase (6 tube) inverter bridge temperature sensor board, Y-Y step-up transformer (12v, 230v, 50HZ), a set of controldesk software controller according to the drawing and MATLAB Swimulin software package. Two independent three-phase inverters, and powered by 42V DC power supply, one of which is a three-phase inverter with neutral line, the generated three-phase voltage is connected to the smart grid through a controllable current breaker and step-up transformer, and a YOKOGAWA power analyzer is used to measure THD.

[0300] Table 7 Performance comparison of existing grid-connected inverter current controller and the proposed scheme (THD%)

[0301]

[0302] At the same time, in the five states of no local load, resistive load, unbalanced load, nonlinear load and dynamic performance, the grid-connected grid voltage tracking THD quality of PI, PR, GA+PI, PR+PI+GA scheme is stable at 1.41%-1.61%, and the power quality of the current controller of the PR+PI+GA+SVM scheme is the best, at 0.89% to 3.56%, and the dynamic performance is excellent.

[0303] During LVRT operation, the inverter attempts to provide reactive power to the grid to increase the voltage at PCC. The reactive power provided by the photovoltaic inverter depends on the reactive power compensation technique used in its control strategy. Figure 6(a) shows the PCC voltage profile and the performance comparison of the reactive power compensation techniques of the existing compensation techniques and the embodiments of the present application. For clarity, this study is divided into two subgroups: during the fault of 150 ms and after the fault is removed, an A-phase ground fault with a 1Ω fault resistance is generated at F. Figure 6(b) shows a comparative analysis of different reactive power compensation techniques for PCC voltage distribution. It is observed that during the fault, the A-phase voltage at PCC follows the grid specification. Therefore, the PV will remain connected to the grid and LVRT operation will occur. The existing static and dynamic methods show oscillations at PCC, while using the proposed method stabilizes the voltage. After fault clearance, the static method requires 200 milliseconds, the dynamic method requires 350 milliseconds, and the method of the embodiments of the present application requires only 100 milliseconds to stabilize the voltage at PCC, and the results obtained show the advantages of the proposed method over the existing technology.

[0304] Embodiment 3

[0305] The embodiments of the present application provide a smart grid power generation and consumption metering monitoring controller, as shown in Figure 1 comprises:

[0306] The electric energy metering module is used to perform electric energy metering according to the three-phase voltage Vpcc at the common point detected by the voltage sensor at the voltage sampling 0 and the three-phase current Ipcc at the common point detected by the current sensor.

[0307] The Internet of Things parameter electric energy monitoring module is used to perform Internet of Things parameter and electric energy monitoring, and is connected with the monitoring / computer control device.

[0308] The variable current grid hardware configuration module is used for accessing the Internet of Things, three-phase current, three currents (three-phase direct current), and accessing the microprocessor through the access middleware (wireless communication module, such as the node control unit wireless Internet adapter).

[0309] The power generation parameter detection control module is used for detecting the output voltage and current (voltage and current at direct current voltage sampling 1 and direct current sampling 1) of the direct current system, the voltage and current (voltage and current at current sampling 1 and voltage sampling 2) output by the inverter, the switching temperature of the inverter (power supply temperature detection), and the voltage (voltage at voltage sampling 0) Vpcc at the common point, and controlling the injection of harmonic current I 谐 , reactive current I 无 or reactive power Q 无 at the common point according to the detection results. Figure 1 Real-time under-current, no-current, and power shortage protection, such as monitoring the voltage at the LCL filter through voltage sampling 2, when it is monitored that the voltage at the LCL filter has harmonic generation, the injection of reverse harmonic current can be controlled for control, and the influence of the harmonic is avoided.

[0310] The bidirectional AC component is used for connecting the Internet of Things, smart grid, and smart grid power generation and power consumption monitoring controller. The power generation parameter detection control module injects harmonic current I 谐 , reactive current I 无 or reactive power Q 无 at the common point of the grid through the bidirectional AC component connected with the smart grid.

[0311] The Internet of Things photovoltaic power generation control system based on GA-SVM modulation sends a current limiting, voltage limiting, and temperature limiting unit protection signal for controlling the switch of the inverter through the SVM wave sending module, and implements overvoltage, undervoltage, overcurrent, and overtemperature protection.

[0312] The direct current switch control component contains an MPPT controller.

[0313] The above only describes the preferred embodiments of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application is included in the protection scope of the present application.

Claims

1. An IoT photovoltaic power generation control system based on GA-SVM modulation, characterized in that, include: The second current modulation module, based on a genetic algorithm, modulates the DC voltage V. dc and the three-phase voltage V at the grid common point pcc Modulation is performed to output a second reference current. Voltage conversion module, used for the second reference current The voltage V is obtained by conversion. a V b V0; The SVM waveform generation module is used to generate waveforms based on the input voltage V. a V b V0 performs vector wave generation; The drive circuit is used to drive each switching module of the photovoltaic inverter according to the signal from the SVM waveform generation module, and control the inverter to perform inversion. The second current modulation module includes: A dual-synchronous decoupled coordinate system phase-locked loop is used to control the three-phase voltage V at the input power grid common point. pcc Phase-locked loop (PLL) is performed and converted to its equivalent synchronous dq reference frame, outputting positive and negative sequence voltages. And +ωt, -ωt; where ω is the angular frequency of the three-phase voltage at the common point of the power grid; The genetic algorithm module uses a genetic algorithm to search for the optimal value of the decision variable k, which corresponds to a set of reference current values. The optimal unbalanced voltage and power requirements are for the corresponding power grid common point; The reference power generation module is used to generate a DC reference voltage V obtained through maximum power point tracking. dc * DC voltage V dc The reference power P is obtained. * ; The reference current generation module is used to generate the current based on the optimal decision variable k and the reference power P. * The positive and negative sequence voltages output by the phase-locked loop in the dual synchronous decoupled coordinate system The conversion is performed to obtain the positive and negative sequence reference currents. The second dq0 / αβ0 transformation module is used to transform the positive and negative sequence reference currents according to +ωt and -ωt. The second reference current is obtained by performing a dq0 / αβ0 coordinate transformation. The positive and negative sequence reference currents The specific calculation process is as follows: Setting k to –1 eliminates active power oscillations, enabling constant active power control. Constant active power control uses the negative sequence reference current calculated by formula (7). conduct: When - 1 < k < 0, complementary constant active power control and balanced negative - sequence reactive power control are adopted, and the balanced negative - sequence reactive power control is carried out using the negative - sequence reference current calculated by formula (8). as follows: When k is set to 0, only positive-sequence current elements are injected into the grid, because all negative-sequence components are eliminated. The positive-sequence reference current is calculated using formula (9). Perform balanced positive sequence active power control: When \(0 < k < 1\), complementary constant reactive power control and balanced positive-sequence active power control are adopted. The balanced positive-sequence active power control is carried out with the positive-sequence reference current calculated by formula (9), and the constant reactive power control is carried out with the negative-sequence reference current calculated by formula (10). The balanced positive-sequence active power control is carried out with the positive-sequence reference current calculated by formula (9), and the constant reactive power control is carried out with the negative-sequence reference current calculated by formula (10). as follows: k=1 eliminates reactive power oscillations, and the negative sequence reference current is calculated using formula (10). Perform constant reactive power control; The reference power P * and positive and negative sequence voltages Input the following formula (13) to generate the negative sequence reference current.

2. The IoT photovoltaic power generation control system based on GA-SVM modulation according to claim 1, characterized in that, The reference power generation module includes: The first comparator is used to compare the DC reference voltage V. dc * and DC voltage V dc Compare; The third PI controller is used to perform proportional-integral calculations on the output voltage of the first comparator, and its transfer function is: It is the proportional gain, K iDC It is integral gain; The second comparator is used to compare the output voltage of the third PI controller with the DC voltage V. dc Compare the two and output the maximum value. The theoretical power calculation module is used to determine the maximum value of the active power ripple at the inverter output terminal, and to take the active power corresponding to the maximum value of the active power ripple at the inverter output terminal as the theoretical power. The third comparator compares the power generated by the maximum voltage output of the second comparator, the theoretical power, and the DC power P. The comparison result is used as the reference power P. * .

3. The IoT photovoltaic power generation control system based on GA-SVM modulation according to claim 1, characterized in that, The voltage conversion module includes: The abc / αβ conversion module is used to convert the input three-phase current I at the power grid common point. pcc Perform an abc / αβ transformation to output the actual positive and negative sequence currents. The second reference current decomposition module is used to decompose the second reference current. Perform positive and negative sequence decomposition to obtain the positive sequence reference current. and negative sequence reference current First composite current i α The generation module is used to generate the positive-sequence reference current. Negative sequence reference current and negative sequence actual current Superposition generates the first composite current i α ; Second composite current i β The generation module is used to generate the positive-sequence reference current. Negative sequence reference current and negative sequence actual current Superposition generates a second composite current i β ; The fourth comparator is used for the second reference current. With the first combined current i α The comparison is performed, and the current value that best matches the current control mode is output. The current control mode refers to constant active power control, complementary constant active power control and balanced negative sequence reactive power control, balanced positive sequence active power control, complementary constant reactive power control and balanced positive sequence active power control, or constant reactive power control. The fifth comparator is used to compare the second reference current. With the second composite current i β The comparison is performed, and the current value that best matches the current control method is output. The first PR controller is used for proportional resonant control of the output current of the fourth comparator, and the output voltage V... a V0; The second PR controller is used for proportional resonant control of the output current of the fifth comparator, and the output voltage V... b V0; The first notch filter is used to filter the output voltage of the first PR controller; The second notch filter is used to filter the output voltage of the second PR controller.

4. The IoT photovoltaic power generation control system based on GA-SVM modulation according to claim 3, characterized in that, Also includes: The first current modulation module is used to modulate the three-phase current I at the inverter output. a I b I c Modulation is performed to output the first reference current I. α2 I β2 I 03 ; The competition control module is used to determine the response speed of the first current modulation module and the second current modulation module, and then switch accordingly to connect the connection line between the first current modulation module and the SVM waveform transmission module with the fastest response speed, while closing the connection line between the first current modulation module and the SVM waveform transmission module with the slowest response speed. If the response speeds of the first current modulation module and the second current modulation module are equal, the module switches accordingly to connect the connection line between the first current modulation module and the SVM waveform transmission module, while closing the connection line between the second current modulation module and the SVM waveform transmission module. The αβ0 / abc conversion module, when the first current modulation module has the best response speed, is used to control the first reference current I transmitted by the contention control module. α2 I β2 I 03 The transformation is performed to obtain the voltage V. a V b 、V0.

5. The IoT photovoltaic power generation control system based on GA-SVM modulation according to claim 4, characterized in that, The first current modulation module includes: Current feedback circuit, the input of the current feedback circuit is three-phase current I a I b I c Used to eliminate errors caused by transmission cables / optical fibers; A zero-order hold, whose input is the output of a current feedback circuit, is used to control the three-phase current I. a I b I c Each phase is transformed from a pulse into a continuous stepped signal; The positive and negative sequence decomposition module is used to decompose the positive and negative sequence of the output current of each phase of the zero-order hold, and output the positive and negative sequence components of the current of each phase. The first programmable gain amplifier (PGA) takes as input the positive and negative sequence components of each phase current output from the positive and negative sequence decomposition module, and is used to perform gain compensation on the input. The proportional gain block's input is the three-phase current I at the inverter output. a I b I c ; A resettable integrator is used to integrate the output current of the proportional gain block; The initial phase angle calculation module takes the output of the resettable integrator as its input and outputs the initial phase angle θ of the output voltage of the resettable integrator. The abc / αβ0 conversion module is used to perform abc / αβ0 conversion on the three-phase current output by the first programmable gain amplifier (PGA) based on the initial phase angle θ output by the initial phase angle calculation module, and output a DC current I. α1 I β1 and zero-sequence current I 01 ; The αβ0 / dq0 conversion module is used to convert DC current I α1 I β1 I 01 Perform αβ0 / dq0 conversion to output active current I. d Reactive current I q and zero-sequence current I 02 ; The first sinusoidal AC scanning block is used to quickly capture the active current I. d The amplitude, phase, and frequency of the first sinusoidal AC scanning block, and the positive terminal of the first sinusoidal AC scanning block connected to the active current I. d The other path is connected to the negative terminal of the grounded AC scanning circuit. An AC scanning circuit probe is connected between the positive terminal and the output terminal of the first sinusoidal AC scanning block. The AC scanning circuit probe is used to scan the grounded AC scanning circuit to ensure that the scanning of the first sinusoidal AC scanning block is not interrupted. The negative terminal of the second sinusoidal AC scanning block is connected to the output of the first sinusoidal AC scanning block, and the positive terminal of the second sinusoidal AC scanning block is connected to the three-phase V. a2 The power factor setting module, with its second sinusoidal AC scanning block used to remove active current I... d microwave, three-phase V a2 The power factor setting module is used to set the three-phase V a2 Power factor, three-phase V a2 Power factor is used to detect active current I. d Is it effective? The first PI controller is used to perform proportional-integral control on the output current of the second sinusoidal AC scanning block. The third sinusoidal AC scanning block is used to quickly capture reactive current I. q The amplitude, phase, and frequency of the third sinusoidal AC scanning block, and the reactive current I input at the negative terminal. q The positive terminal of the third sinusoidal AC scanning block is connected to the three-phase V. a1 Power factor setting module, three-phase V a1 The power factor setting module is used to set the three-phase V a1 Power factor, three-phase V a1 Power factor is used to detect reactive current I. q Is it effective? The second PI controller is used to perform proportional-integral control on the output current of the third sinusoidal AC scanning block. The first dq0 / αβ0 transform module, the I of the first dq0 / αβ0 transform module d The output of the first PI controller is terminated, and the I of the first dq0 / αβ0 conversion module is... q The output of the second PI controller is connected to the terminal, and the zero-sequence current I is connected to the terminal of the first dq0 / αβ0 conversion module. 02 And the initial phase angle θ, the first dq0 / αβ0 transformation module is used to perform dq0 / αβ0 transformation on the input current according to θ, and output the first reference current I. α2 I β2 I 03 .

6. A method for controlling photovoltaic power generation via the Internet of Things based on GA-SVM modulation, characterized in that, The IoT photovoltaic power generation control system based on GA-SVM modulation as described in claim 4 is implemented according to the following steps: Step S1: Set the parameters for the first current modulation module, the second current modulation module, the PR controller, and the notch filter; Step S2: Receive the three-phase voltage Vpcc and the three-phase current I at the smart grid common point. pcc The three-phase current I at the inverter output terminal a I b I c And the DC output voltage V of the photovoltaic cell dc ; Step S3: Real-time acquisition and determination of whether the first reference current I is generated. α2 I β2 I 03 Second reference current According to the first reference current I α2 I β2 I 03 Second reference current The response speed is determined to be the optimal one between the first current modulation module and the second current modulation module. If the second current modulation module is the optimal one, a corresponding switch is made to connect the connection line between the second current modulation module and the SVM waveform generation module, while the connection line between the first current modulation module and the SVM waveform generation module is closed, and then proceed to step S5; otherwise, proceed to step S4. Step S4: For the first reference current I α2 I β2 I 03 Perform αβ0 / abc transformation to obtain voltage V a V b V0; Step S5: Adjust the second reference current. With the first combined current i α The comparison is performed, and the best output is sequentially converted by the PR controller to obtain the voltage V. a V0; for the second reference current With the second composite current i β The comparison is performed, and the best output is sequentially converted by the PR controller to obtain the voltage V. b V0; then the voltage V a V b V0 is notched filtered by a notch filter; Step S6: Based on the voltage V output in step S4 a V b V0 or the voltage V output after notch filtering in step S5 a V b V0, based on SVM waveform generation, controls the switching module that drives the inverter; The PR controller includes a first PR controller and a second PR controller; the first PR controller is used to perform proportional resonant control on the output current of the fourth comparator, and the output voltage V a V0; the second PR controller, used for proportional resonant control of the output current of the fifth comparator, and the output voltage V b V0; The notch filter includes a first notch filter and a second notch filter; the first notch filter is used to filter the output voltage of the first PR controller; the second notch filter is used to filter the output voltage of the second PR controller.

7. The IoT photovoltaic power generation control method based on GA-SVM modulation according to claim 6, characterized in that, Second reference current Generate according to the following steps: Step S31: Calculate the active voltage V using formula (1) or formula (2). d Reactive voltage V q And zero voltage V0, and relative to active voltage V d Reactive voltage V q Performing positive and negative sequence decomposition on the zero voltage V0, we obtain When the q-axis leads the d-axis: When the q-axis lags behind the d-axis: in, Phase A V a The phase angle; Step S32: Under the constraint of DC bus voltage fluctuation ΔV, the decision variable k is defined by formula (3), and the fitness value is calculated based on the genetic algorithm and combined with formula (6) to search for the optimal decision variable k: Where ω is the angular frequency of the three-phase voltage at the common point of the power grid, V c DC bus capacitor C DC The voltage; F(k)=K n (ω1f1(k)+ω2f2(k)+ω2f0(k)); (6) Where ω1 is the active voltage angular frequency, ω2 is the reactive voltage angular frequency, and f1(k) is the active power oscillation P. rip The active power ripple function is defined by equation (4), and f2(k) is the reactive power oscillation Q. rip The reactive power ripple function defined by equation (5) has priority over the reactive power ripple function f2(k) in terms of active power ripple function f1(k). n It is a parallel connection number, f0(k) is the zero vector value, used to solve the problem of repeated wave generation; k satisfies -1≤k≤+1, and can take any value between -1 and 1; Step S33: Take the active power corresponding to the maximum active power ripple at the inverter output as the theoretical power, and apply it to the DC reference voltage V obtained through maximum power point tracking. dc * With DC voltage V dc After comparison, PI control is performed. The power generated by PI control is compared with the theoretical power and the DC power P to obtain the reference power P. * ; Step S34: Based on the optimal decision variable k and reference power P * Calculate the positive and negative sequence reference currents. The specific process is as follows: Setting k to –1 eliminates active power oscillations, enabling constant active power control. Constant active power control uses the negative sequence reference current calculated by formula (7). conduct: When - 1 < k < 0, complementary constant active power control and balanced negative - sequence reactive power control are adopted, and the balanced negative - sequence reactive power control is carried out with the negative - sequence reference current calculated by formula (8). as follows: When k is set to 0, only positive-sequence current elements are injected into the grid, because all negative-sequence components are eliminated. The positive-sequence reference current is calculated using formula (9). Perform balanced positive sequence active power control: When \(0 < k < 1\), complementary constant reactive power control and balanced positive-sequence active power control are adopted. The balanced positive-sequence active power control is carried out with the positive-sequence reference current calculated by formula (9). The constant reactive power control is carried out with the negative-sequence reference current calculated by formula (10). as follows: k=1 eliminates reactive power oscillations, and the negative sequence reference current is calculated using formula (10). Perform constant reactive power control; The reference power P * and positive and negative sequence voltages Input the following formula (13) to generate the negative sequence reference current. Step S35: Based on +ωt and -ωt, adjust the positive and negative sequence reference currents under different control modes selected according to the k value. Perform dq0 / αβ transformation to generate a second reference current. The transfer function G of the PR controller PR (S) is: Where, k p For proportional gain, k i Let S be the resonant gain, S be the Laplace operator, and ω be the resonant gain. c ω is the system frequency, and ω0 is the reference frequency.

8. A smart grid power generation and consumption metering and monitoring controller, characterized in that, include: The IoT photovoltaic power generation control system based on GA-SVM modulation as described in any one of claims 1-3 and 5, wherein the IoT photovoltaic power generation control system based on GA-SVM modulation sends current limiting, voltage limiting, and temperature limiting unit protection signals to control the switching of the inverter via the SVM wave generation module, and implements overvoltage, undervoltage, overcurrent, and overtemperature protection.

9. A smart grid power generation and consumption metering monitoring controller according to claim 8, characterized in that, Also includes: The electricity metering module is used to measure the three-phase voltage V at the common point of the power grid, as detected by a voltage sensor at the common point. pcc The three-phase current I at the common point detected by the current sensor pcc To perform electricity metering; The IoT parameter power monitoring module is used to monitor IoT parameters and power, and connects to the monitoring / computer control device. The converter grid hardware configuration module is used to connect to the Internet of Things, three-phase current, and three current, and connects to the microprocessor through access middleware; Two-way communication device for connecting to the Internet of Things and smart grids; The power generation parameter detection and control module is used to detect the output voltage and current of the DC system, the output voltage and current of the inverter, the switching temperature of the inverter, and the voltage Vpcc and current Ipcc at the point of common. Based on the detection results, it controls the injection of harmonic current I into the grid point of common through a bidirectional AC component connected to the smart grid. 谐 Reactive current I 无 or reactive power Q 无 Implement undercurrent, no current, and insufficient power protection; The drive circuit of the IoT photovoltaic power generation control system based on GA-SVM modulation includes: Pulse Minimum Compensation Limit Module This is used to minimize the waveform delay and prevent synchronous waveform generation by the IoT photovoltaic power generation control system based on GA-SVM modulation when the power generation parameter detection and control module injects harmonic current, reactive current, or reactive power. The delay time is consistent with the time of harmonic current, reactive current, or reactive power injection. The input of the minimum compensation limit module for each pulse is the three-phase pulse output by the SVM waveform generation module. The second programmable gain amplifier (PGA) has its input being the corresponding pulse minimum compensation limit module. The output signal is used for gain compensation; the output of each second programmable gain amplifier (PGA) is connected to the two switch module drive terminals of the corresponding bridge arm on the inverter via two gate buffers. Each second programmable gain amplifier (PGA) has a power scan meter led out from it. The power scan meter is used to determine whether the injection of harmonic current, reactive current, or reactive power is complete. When the injection of harmonic current, reactive current, or reactive power is complete, the second programmable gain amplifier (PGA) starts to operate and enters the wave generation process.

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