A filter anti-jamming reconstruction method and device

Abstract

The application discloses a filtering anti-interference reconstruction method and device, and relates to the photovoltaic power generation field. pv and port current I pv ; step 102, a control period Ts of a PWM control module in a control system from an MPPT is acquired, and after processing, a detection and calculation step length Tp is obtained; step 103, according to the port voltage U pv , the port current I pv and the detection and calculation step length Tp, a power derivative value PV2 of the voltage is obtained; step 104, a periodic disturbance signal δD is obtained through the detection and calculation step length Tp; compared with the prior art, the application has the beneficial effects that the application avoids the positive and negative misjudgment of the deviation value of the port voltage and the port power P caused by noise in the duty cycle disturbance algorithm, and makes the working point more stable; and the hysteresis is introduced, and the anti-interference capability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic power generation, and particularly relates to a filtering anti-interference reconstruction method and device. BACKGROUND

[0002] As a clean and pollution-free renewable energy, photovoltaic power generation has been widely concerned and applied in the world. Maximum power point tracking (MPPT) is a commonly used photovoltaic solar system technology, which aims to obtain maximum power output in various situations. The perturbation and observation method is the most commonly used direct MPPT algorithm. The advantage is that it can track the maximum power point under various irradiance, temperature and photovoltaic panel aging degree, ensuring the robustness and reliability of the system.

[0003] In the practice process, it is found that in the duty cycle perturbation algorithm of the perturbation and observation method of MPPT in the book Photovoltaic Power Generation Maximum Power Point Tracking Control Technology by Nicola Fermi et al., as shown in Figure 1 and Figure 2 , the noise introduced in the detection and signal conditioning circuit is ignored. The occurrence of noise will cause the positive and negative misjudgment of the deviation value of the port voltage and the port power P, which will make the working point very unstable. Due to the uniqueness of the optimal working point, when tracking the optimal working point, the power will oscillate near the maximum power point, and the anti-interference ability is weak, which needs to be improved. SUMMARY

[0004] The purpose of the present application is to provide a filtering anti-interference reconstruction method and device to solve the problems raised in the background art.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A filtering anti-interference reconstruction method, comprising the following steps:

[0007] Step 101, obtaining the port voltage and the port current of the photovoltaic array;

[0008] Step 102, obtaining the control period Ts of the PWM control module in the control system from the MPPT, (after processing by the module) obtaining the detection and calculation step Tp;

[0009] Step 103, obtaining the power derivative value PV2 of the voltage according to the port voltage , the port current of the photovoltaic array and the detection and calculation step Tp;

[0010] Step 103 includes:

[0011] Step 1031, according to the port voltage of the photovoltaic array , the port current and the detection and calculation step length Tp, the time voltage of the photovoltaic array K+2 is obtained , the time current , so as to obtain the time output power of the photovoltaic array K+2 ;

[0012] Step 1032, the second-order differential filtering processing is performed on the port voltage of the photovoltaic array and the port power P of the photovoltaic array to obtain the derivative of the filtered port voltage of the photovoltaic array , the derivative of the port power P ;

[0013] Step 1033, according to the derivative and , the trapezoidal formula discretization is performed to obtain the derivative value of the time voltage of the filtered photovoltaic array K+2 , the derivative value of the time output power , the power derivative value PV2 of the voltage, to avoid the positive and negative misjudgment of the deviation value of the port voltage and the port power P;

[0014] Step 104, the periodic disturbance signal D is obtained by detecting and calculating the step length Tp;

[0015] Step 105, according to the derivative value of the time voltage of the filtered photovoltaic array K+2 , the derivative value of the time output power , the power derivative value PV2 of the voltage and the disturbance signal D, the duty cycle D is obtained and output to the PWM control module of the control system of the MPPT.

[0016] As a further scheme of the application: in step 102, the control period Ts from the PWM control module of the control system of the MPPT is obtained, and the detection and calculation step length Tp is obtained after the processing of the module; In the process of calculating Tp by the module, the formula Tp= *Ts is used, wherein is a positive integer.

[0017] As a further scheme of the application: in step 1031, according to the port voltage of the photovoltaic array , the port current and detecting and calculating step length Tp, continuously obtaining three step lengths of photovoltaic array current, voltage value, namely photovoltaic array k time moment voltage , time moment current , photovoltaic array k+1 time moment voltage , photovoltaic array k+2 time moment voltage , time moment current ; according to the voltage and current values, obtaining photovoltaic array k time moment output power , photovoltaic array k+1 time moment output power , photovoltaic array k+2 time moment output power .

[0018] As a further scheme of the application: in step 1032, the port voltage of the photovoltaic array and the port power P of the photovoltaic array are subjected to second-order differential filtering processing, and the formula is used to obtain the derivative of the filtered port voltage of the photovoltaic array and the derivative of the port power P.

[0019] As a further scheme of the application: in step 1033, the derivative and are subjected to trapezoidal formula discretization, and the discrete formula is:

[0020]

[0021]

[0022] wherein, ;

[0023] Using the discrete formula, the derivative value of the filtered photovoltaic array k+2 time moment voltage and the derivative value of the time moment output power can be obtained, and the derivative of (k+2) time moment P with respect to is obtained according to the formula , wherein the power derivative value of the voltage .

[0024] As a further scheme of the application: in step 104, every three detection and calculation step lengths are set, and a perturbation signal D is obtained.

[0025] As a further scheme of the application: in step 105, a perturbation signal D and keep three duty cycles unchanged, that is, duty cycle D(k)=D(k+1)=D(k+2), and set a hysteresis width H (H>0), by obtaining the power derivative value PV2 of the voltage and H comparison:

[0026] When , the derivative corresponding to k+2 time , keep the duty cycle unchanged in the next detection process, that is, obtain ;

[0027] When , the derivative corresponding to k+2 time , judge: if , obtain , ; if , obtain , ;

[0028] When , the derivative corresponding to k+2 time , judge: if , obtain , ; if , obtain , ;

[0029] The obtained duty cycle D(k+3) is used as the new duty cycle, and is processed by the PWM control module in the MPPT control system to obtain a new PWM control signal.

[0030] A filter anti-interference reconstruction device, comprising:

[0031] A module for obtaining a detection and calculation step length Tp corresponding to a control period Ts of a PWM control module according to the control period Ts;

[0032] A second-order linear differential filter module for obtaining a filtered derivative value of a port voltage of a photovoltaic array at K+2 time , a derivative value of a port current , and a detection and calculation step length Tp of the photovoltaic array K+2 time , a derivative value of output power , and a power derivative value PV2 of the voltage;

[0033] A duty cycle disturbance module for obtaining a periodic disturbance signal D according to the detection and calculation step length Tp;

[0034] A hysteresis module for obtaining a filtered derivative value of a port voltage of a photovoltaic array at K+2 time derivative value of the momentary output power derivative value of the power of the voltage and the periodic disturbance signal D, obtaining the duty cycle D;

[0035] The output end of the module is connected with the input end of the duty cycle disturbance module, the first input end of the second-order linear differential filter module, the output end of the duty cycle disturbance module is connected with the first input end of the hysteresis module, and the first, second and third output ends of the second-order linear differential filter module are connected with the second, third and fourth input ends of the hysteresis module.

[0036] As a further scheme of the application, the output end of the hysteresis module is connected with the input end of the PWM control module, the first output end of the PWM control module is connected with the input end of the module, the second output end of the PWM control module is connected with the input end of the DC / DC module of the MPPT main circuit, and the output port voltage and the port current of the photovoltaic array of the MPPT main circuit to the second input end and the third input end of the second-order linear differential filter module.

[0037] Compared with the prior art, the application has the beneficial effects that: the application avoids the positive and negative misjudgments of the deviation values of the port voltage and the port power P caused by noise in the duty cycle disturbance algorithm, so that the working point becomes more stable; and the hysteresis is introduced to improve the anti-interference ability. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a flowchart of the duty cycle disturbance algorithm of the existing perturb and observe method.

[0039] Figure 2 It is a structural diagram of the duty cycle disturbance algorithm of the existing perturb and observe method.

[0040] Figure 3 It is a flowchart of a filtering anti-interference reconstruction method.

[0041] Figure 4 It is a structural diagram of a filtering anti-interference reconstruction device.

[0042] Figure 5 It is a structural diagram of a filtering anti-interference reconstruction device applied to an MPPT control system. DETAILED DESCRIPTION

[0043] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0044] Please refer to Figure 3 A filter anti-interference reconstruction method, comprising the following steps:

[0045] Step 101, obtaining the port voltage of the photovoltaic array and the port current ;

[0046] Step 102, obtaining the control period Ts of the PWM control module in the control system from the MPPT, (after processing by the module) obtaining the detection and calculation step Tp;

[0047] Step 103, obtaining the power derivative value PV2 of the voltage according to the port voltage , the port current and the detection and calculation step Tp of the photovoltaic array;

[0048] Step 103 includes:

[0049] Step 1031, obtaining the time voltage , the time current of the photovoltaic array at K+2 time according to the port voltage , the port current of the photovoltaic array and the detection and calculation step Tp, so as to obtain the time output power of the photovoltaic array at K+2 time;

[0050] Step 1032, performing second-order differential filtering processing on the port voltage of the photovoltaic array and the port power P of the photovoltaic array, obtaining the derivative of the filtered port voltage of the photovoltaic array, the derivative of the port power P;

[0051] Step 1033, performing trapezoidal formula discretization according to the derivative and , obtaining the derivative value of the time voltage, the derivative value of the time output power, the power derivative value PV2 of the voltage after filtering the photovoltaic array at K+2 time, avoiding the positive and negative misjudgment of the deviation value of the port voltage and the port power P;​

[0052] Step 104: Obtain the periodic disturbance signal by detecting and calculating the step size Tp. D;

[0053] Step 105: Based on the derivative value of the voltage at time K+2 of the filtered photovoltaic array. The derivative of the output power at time 1 The power derivative of the voltage PV2 and the disturbance signal D, obtain the duty cycle D, and output it to the PWM control module in the MPPT control system.

[0054] In a specific embodiment: Please refer to Figure 1 and Figure 2 Existing perturbation observation methods' duty cycle perturbation algorithms are ineffective when measuring port voltage. and port current Furthermore, the signal conditioning circuit introduces a significant amount of noise, which can cause port voltage fluctuations. The deviation value from the port power P is misjudged as positive or negative; when the port voltage... When the deviation value should be positive, the presence of noise may cause it to... The deviation value became negative, causing the calculated new power Pnew to deviate significantly from the actual power. This resulted in a suboptimal duty cycle being obtained, leading to poor tracking performance. Furthermore, from... Figure 1 It can be concluded that each time a disturbance is applied, the duty cycle will change, which will cause the power to oscillate around the maximum power point, resulting in weak anti-interference ability.

[0055] In this embodiment: Please refer to Figure 3 In step 102, the control period Ts from the PWM control module in the MPPT control system is obtained, and then... The module processes the data to obtain the detection and calculation step size Tp. During the module's calculation of Tp, the formula Tp= *Ts, where It is a positive integer.

[0056] In this embodiment: Please refer to Figure 3 In step 1031, based on the port voltage of the photovoltaic array... Port current The system detects and calculates the step size Tp, continuously acquiring the current and voltage values ​​of the photovoltaic array for three consecutive steps, i.e., the voltage at time k of the photovoltaic array. Current at any moment The voltage at time k+1 of the photovoltaic array The voltage at time k+2 of the photovoltaic array Current at any moment Based on the voltage and current values, obtain the output power of the photovoltaic array at time k. Output power of the photovoltaic array at time k+1 Output power of the photovoltaic array at time k+2 .

[0057] In this embodiment: Please refer to Figure 3 In step 1032, the port voltage of the photovoltaic array The second-order differential filter is applied to the port power P of the photovoltaic array, using the formula... Where s is the Laplace operator and λ is the filtering time factor, the port voltage of the filtered photovoltaic array is obtained. derivative The derivative of port power P .

[0058] In this embodiment: Please refer to Figure 3 In step 1033, the derivative and Discretize the trapezoidal rule; the discretized formula is as follows:

[0059]

[0060]

[0061] in, k represents time, which is a positive constant. s is the Laplace operator, and λ is the filtering time factor.

[0062] The derivative of the voltage at time K+2 of the filtered photovoltaic array can be obtained using the discrete formula. The derivative of the output power at time 1 According to the formula We obtain P at time (k+2) with respect to derivative The power derivative of the voltage .

[0063] Step 103 completed the port voltage measurement of the photovoltaic array. Filtering of the port power P of the photovoltaic array to avoid port voltage... The deviation value of the port power P is misjudged as positive or negative.

[0064] In this embodiment: Please refer to Figure 3 In step 104, a step size is set every three detection and calculation steps. Obtain a disturbance signal D.

[0065] Here, every three detection and calculation steps are used. Obtain a disturbance signal For example, in actual use, D does not impose any restrictions.

[0066] In this embodiment: Please refer to Figure 3 In step 105, a perturbation signal is applied. D maintains three constant duty cycles, i.e., duty cycle D(k) = D(k+1) = D(k+2), and sets a hysteresis width H (H>0). The power derivative value PV2 of the obtained voltage is compared with H:

[0067] when When, then the derivative corresponds to time k+2. To maintain the same duty cycle in the next detection process, thus obtaining... ;

[0068] when When, then the derivative corresponds to time k+2. Make a judgment: if ,get , ;like ,get , ;

[0069] when When, then the derivative corresponds to time k+2. Make a judgment: if ,get , ;like ,get , ;

[0070] The obtained duty cycle D(k+3) is used as the new duty cycle and processed by the PWM control module in the MPPT control system to obtain a new PWM control signal.

[0071] In this embodiment: Please refer to Figure 4 A filtering anti-interference reconstruction device, comprising:

[0072] This module is used to obtain the detection and calculation step size Tp corresponding to the control period Ts of the PWM control module.

[0073] A second-order linear differential filter module is used to filter based on the port voltage of the photovoltaic array. Port current By detecting and calculating the step size Tp, the derivative of the voltage at time K+2 of the filtered photovoltaic array is obtained. The derivative of the output power at time 1 , the power derivative value of the voltage PV2;

[0074] a duty cycle perturbation module for obtaining a periodic perturbation signal according to the detection and calculation step Tp D;

[0075] a hysteresis module for obtaining the derivative value of the instantaneous voltage of the filtered photovoltaic array at the K+2 time , the derivative value of the instantaneous output power , the power derivative value of the voltage PV2 and the periodic perturbation signal D, the duty cycle D is obtained.

[0076] The output end of the module is connected to the input end of the duty cycle perturbation module, the first input end of the second-order linear differential filtering module, the output end of the duty cycle perturbation module is connected to the first input end of the hysteresis module, and the first, second and third output ends of the second-order linear differential filtering module are connected to the second, third and fourth input ends of the hysteresis module.

[0077] In this embodiment, please refer to Figure 5 , the output end of the hysteresis module is connected to the input end of the PWM control module, and the first output end of the PWM control module is connected to the input end of the module, and the second output end of the PWM control module is connected to the input end of the DC / DC module of the MPPT main circuit, and the port voltage , the port current of the photovoltaic array output end of the MPPT main circuit is given to the second input end and the third input end of the second-order linear differential filtering module.

[0078] The second-order linear differential filtering module is used to obtain the derivative value of the instantaneous voltage of the filtered photovoltaic array at the K+2 time , the derivative value of the instantaneous output power , the power derivative value of the voltage PV2 according to the obtained port voltage and the port current of the photovoltaic array, and then the detection and calculation step Tp is obtained through the n0 module according to the control period Ts of the PWM control module, and the periodic perturbation signal D is obtained through the duty cycle perturbation module according to the detection and calculation step Tp , the derivative value of the instantaneous output power , the power derivative value of the voltage PV2 and the perturbation signal D, and finally the duty cycle D is obtained through the hysteresis module according to the derivative value of the instantaneous voltage of the filtered photovoltaic array at the K+2 time

[0079] The control system of the MPPT comprises an MPPT main circuit, a PWM control module, the MPPT main circuit comprises a DC / DC module, a photovoltaic array (PV array) Figure 5 a black triangle at the upper left corner), and a load.The DC / DC module is connected with the photovoltaic array and the load respectively.

[0080] The present application avoids the positive and negative misjudgment of the deviation value of the port voltage and the port power P caused by noise in the duty cycle disturbance algorithm, so that the working point becomes more stable; and the hysteresis is introduced to improve the anti-interference ability.

[0081] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view.

[0082] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments which can be understood by those skilled in the art.

Claims

1. A filter-robust reconstruction method, characterized in that, The filtering anti-interference reconstruction method comprises the following steps: Step 101, acquiring port voltage of photovoltaic array and port current ; In step 102, the control period Ts of the PWM control module in the control system from the MPPT is obtained, and after processing, the detection and calculation step Tp is obtained. Step 103, obtaining the power derivative value PV2 of the voltage according to the port voltage , the port current and the detection and calculation step Tp; Step 103 comprises: Step 1031, according to the port voltage of the photovoltaic array , port current and detection and calculation step Tp, obtain the time voltage of the photovoltaic array K+2 moment , time current , so as to obtain the time output power of the photovoltaic array K+2 moment ; Step 1032, the port voltage of the photovoltaic array and the port power P of the photovoltaic array are subjected to a second-order differential filtering process to obtain the derivative of the filtered port voltage of the photovoltaic array the derivative of the port power P of the photovoltaic array ; Step 1033, according to the derivative And Carry out trapezoidal formula discretization, obtain the derivative value of the filtered photovoltaic array K+2 time moment voltage , the derivative value of the time output power , the power derivative value PV2 of the voltage, avoid the positive and negative misjudgment of the deviation value of the port voltage And port power P Step 104, the periodic disturbance signal is obtained by detecting the calculation step length Tp D; Step 105, according to the filtered photovoltaic array K+2 time of the time derivative of voltage value , the derivative of the output power value , the power derivative of the voltage PV2 and the perturbation signal D, the duty cycle D is obtained, output to the control system of MPPT PWM control module.

2. The filter-anti-jam reconfiguration method of claim 1, wherein, In step 102, the control period Ts of the PWM control module in the control system from the MPPT is obtained, and the control period Ts is passed through The detection and calculation step Tp is obtained after the module processing; In the process of calculating Tp, the formula Tp = k * Ts is adopted, where k is a positive integer. *Ts, where k is a positive integer. is a positive integer.

3. The filter-anti-jam reconfiguration method of claim 1, wherein, In step 1031, according to the port voltage , port current and detection and calculation step length Tp, the current, voltage values of the photovoltaic array in three steps are continuously obtained, that is, the time voltage , time current of the photovoltaic array at time k, the time voltage of the photovoltaic array at time k+1, the time voltage , time current of the photovoltaic array at time k+2; according to the voltage and current values, the time output power of the photovoltaic array at time k, the time output power of the photovoltaic array at time k+1, and the time output power of the photovoltaic array at time k+2 are obtained.

4. The filter-anti-jam reconfiguration method of claim 1, wherein, In step 1032, the port voltage of the photovoltaic array The second-order differential filter is applied to the port power P of the photovoltaic array, using the formula... Obtain the filtered port voltage of the photovoltaic array. derivative The derivative of port power P .

5. The filter-anti-jam reconfiguration method of claim 1, wherein, In step 1033, the derivative and The trapezoidal formula discretization is performed, and the discrete formula is: wherein ; The derivative value of the filtered photovoltaic array voltage at time k+2 is obtained using a discrete formula The derivative value of the filtered photovoltaic array output power at time k+2 is obtained using a discrete formula The derivative value of the filtered photovoltaic array output power at time k+2 is obtained using a discrete formula The derivative value of the filtered photovoltaic array output power at time k+2 is obtained using a discrete formula The derivative value of the filtered photovoltaic array output power at time k+2 is obtained using a discrete formula The derivative value of the filtered photovoltaic array output power at time k+2 is obtained using a discrete formula The derivative value of the filtered photovoltaic array output power at time k+2 is obtained using a discrete formula 6. The filter-anti-jam reconfiguration method of claim 1, wherein, In step 104, every third detection and calculation step is set , a disturbance signal is obtained D.

7. The filter-anti-jam reconfiguration method of claim 1, wherein, In step 105, a perturbation signal is applied D and keep three duty cycles unchanged, that is, duty cycle D(k) = D(k+1) = D(k+2), and set a hysteresis width H (H>0), by the power derivative value PV2 of the obtained voltage and H are compared: When , then the derivative at time k+2 , the duty cycle is maintained constant during the next detection process, i.e. obtaining ; When , then the derivative at k+2 is , a decision is made: if , then the value at k+2 is , ; if , then the value at k+2 is , ; When , then the derivative at k+2 is , a decision is made: if , then the value at k+2 is obtained , ; if , then the value at k+2 is obtained , ; The obtained duty ratio D(k+3) is used as a new duty ratio, and after processing by the PWM control module in the control system of the MPPT, a new PWM control signal is obtained.

8. A filtering and interference rejection reconstruction apparatus for use in the filtering and interference rejection reconstruction method according to any one of claims 1 to 7, characterized by The filtering anti-interference reconstruction device comprises: a module for obtaining a detection and calculation step Tp corresponding to a control period Ts of the PWM control module according to the control period Ts; a second order linear differential filter module for deriving the derivative of the voltage at time instant K+2 of the filtered photovoltaic array from the port voltage , the port current and the detection and computation step Tp , the derivative of the output power at time instant K+2 , the power derivative of the voltage PV2; A duty cycle perturbation module is used to obtain a periodic perturbation signal according to the detection and the calculation step Tp D; a hysteresis module for obtaining a derivative value of the time-voltage at the time instant K+2 of the filtered photovoltaic array a derivative value of the time-voltage a derivative value of the time-voltage D, obtaining a duty cycle D; The output end of the module is connected with the input end of the duty cycle disturbance module and the first input end of the second-order linear differential filter module. The output end of the duty cycle disturbance module is connected with the first input end of the hysteresis module. The first, second and third output ends of the second-order linear differential filter module are connected with the second, third and fourth input ends of the hysteresis module.

9. The filtered despread reconstruction apparatus of claim 8, wherein, The output end of the hysteresis module is connected with the input end of the PWM control module, the first output end of the PWM control module is connected with the input end of the DC / DC module of the MPPT main circuit, the second output end of the PWM control module is connected with the input end of the DC / DC module of the MPPT main circuit, the output end of the photovoltaic array of the MPPT main circuit is connected with the voltage , the port current is connected with the second input end and the third input end of the second-order linear differential filtering module.

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