Harmonic analysis method and control device for multi-infeed receiving end power grid system

Abstract

The invention provides a multi-infeed receiving-end power grid system harmonic analysis method and a control device, and aims to solve the problems in the aspects of safety and reliable operation of a high-proportion power electronic power system: firstly, high-proportion new energy access causes scarcity of traditional frequency regulation resources and complexity of frequency dynamic, and secondly, high-proportion new energy access causes high-proportion new energy access to cause high-proportion new energy access to cause high-proportion new energy access to cause high-proportion new energy access. In order to solve the problems that new energy power generation equipment mostly adopts a power electronic converter interface and lacks inertia in the traditional sense, so that the voltage supporting capability of a system is weak and the voltage stability is poor, the invention provides a power electronic converter interface. The reliability of each component of the system is improved; the reliability of the system is improved by accurately evaluating the quantitative index of the reliability of the component, monitoring the capability and perfecting the evaluation of the aging degree of the component; and developing a novel protection device and an emergency control means: researching a prevention and control means aiming at a novel stability problem, enhancing online monitoring of a safety automatic device state and an available measure quantity, and ensuring the effectiveness of a stable control measure in a power electronization and power distribution network active environment.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a harmonic analysis method and a control device for a multi-feed receiving-end power grid system. Background Art

[0002] Photovoltaic power generation is a power generation system that converts solar radiation into electrical energy based on the photovoltaic effect. It converts solar energy into direct current through photovoltaic cells, and then converts direct current into alternating current through an inverter. Photovoltaic power generation is a clean, renewable energy source that is environmentally friendly and has broad application prospects.

[0003] The frequency response analysis of the motor control strategy is carried out to evaluate the system performance at different frequencies, especially the response at sub / super synchronous harmonic frequencies. By introducing active damping elements in the control system, the control parameters are designed for sub / super synchronous harmonic frequencies to increase the damping of the system and suppress oscillation. Current feedforward for sub / super synchronous harmonics is added to the input of the motor controller to compensate or suppress these harmonic components. By adjusting the parameters of the proportional, integral and resonant terms, the harmonic current in the motor is effectively suppressed, the operating efficiency and stability of the motor are improved, the switching frequency is optimized, and the harmonic amplification problem caused by the switching frequency being close to the harmonic frequency is avoided. An active power filter is integrated in the electrode drive system to monitor and actively compensate for the harmonic current of the system in real time, improve the power quality, optimize the parameters of the motor and control system, and reduce the sensitivity of the system to sub / super synchronous harmonics. Before practical application, the above control strategy needs to be simulated and verified using simulation software to evaluate its effectiveness. At the same time, experimental verification is carried out under laboratory conditions to ensure that the control strategy can work stably in actual operation and effectively suppress sub-super synchronous oscillation harmonics. Through these analysis methods and control strategies, the performance of the motor system can be effectively improved, electromagnetic interference can be reduced, and the stable operation of the power system can be ensured.

[0004] Some large factories have their own photovoltaic power stations, which generate electricity to maintain the normal operation of the factory and reduce electricity costs. After the factory expands its production scale, the factory's electricity consumption will also increase. However, in the actual production and operation process, there is such a problem: in some areas, power restriction policies will be implemented, which will strictly restrict the factory's purchase of electricity, which will lead to tight power purchases for the factory and bring great difficulties to the operation of the factory. Therefore, it is necessary to provide an analysis method to optimize the photovoltaic power station when power is restricted, increase the number of photovoltaic cells, and increase the power generation of the photovoltaic power station to meet the electricity demand and maintain the normal operation of the factory. Summary of the invention

[0005] Therefore, the present invention provides a harmonic analysis method and control device for a multi-input receiving-end power grid system to optimize photovoltaic power stations and meet the needs of industrial electricity consumption.

[0006] To solve the above problems, the present invention provides a harmonic analysis method and control device for a multi-feed receiving-end power grid system. The photovoltaic power station includes: photovoltaic cells, inverters, storage modules and harmonic suppression modules. The analysis method includes: obtaining the total power consumption of the current load; obtaining the storage voltage according to the total power consumption; controlling the harmonic suppression module to suppress the first harmonic voltage of the inverter; obtaining the second harmonic voltage of the inverter; obtaining the first power generation of the photovoltaic power station according to the storage voltage and the second harmonic voltage; obtaining the number of photovoltaic cells according to the first power generation; wherein the total power consumption is the sum of the rated voltages of the loads, the storage voltage is the voltage stored in the storage module, the first harmonic voltage is the harmonic voltage before the inverter is suppressed, the second harmonic voltage is the harmonic voltage after the inverter is suppressed, and the first power generation is the power generation actually required by the photovoltaic power station.

[0007] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the total power consumption of the current load is obtained, and the storage voltage is obtained based on the total power consumption so that the storage voltage can meet the voltage required by the load. The harmonic suppression module suppresses the harmonics generated by the inverter to reduce energy loss, and then the second harmonic voltage after the inverter is suppressed is obtained. The first power generation of the photovoltaic power station is the actual power generation. The first power generation can be obtained based on the second harmonic voltage and the storage voltage, and then the number of required photovoltaic cells is determined based on the first power generation. The number of photovoltaic cells obtained by the actual power generation is more accurate, which reduces the prediction error.

[0008] Furthermore, controlling the harmonic suppression module to suppress the harmonic voltage specifically includes: acquiring an input voltage of the inverter; obtaining a control parameter of the inverter according to the input voltage; and obtaining a drive pulse of the inverter according to the control parameter.

[0009] Compared with the prior art, the technical effect achieved by adopting this technical solution is: obtaining the input voltage of the inverter, obtaining the control parameters according to the input voltage, and thus obtaining the driving pulse of the inverter, making the control of the driving pulse of the inverter more scientific and reliable.

[0010] Furthermore, after the drive pulse of the inverter is obtained according to the control parameter, the control method further includes: controlling the inverter to operate with the drive pulse; and obtaining the harmonic current of the inverter.

[0011] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: after the harmonic suppression module is suppressed, the inverter is controlled to continue to run, and the harmonic current of the inverter is obtained.

[0012] Furthermore, obtaining a second harmonic voltage according to the harmonic current also includes: obtaining the harmonic impedance of the inverter, and obtaining the second harmonic voltage according to the harmonic current and the harmonic impedance.

[0013] Compared with the prior art, the technical effect achieved by adopting this technical solution is: the harmonic impedance of the inverter is obtained, and the second harmonic voltage of the inverter after suppression can be obtained according to the harmonic current and harmonic impedance. After the harmonic suppression module works, the harmonics of the inverter cannot be completely eliminated. Therefore, in the subsequent analysis process, it is necessary to obtain the harmonic voltage after suppression, so that when obtaining the first power generation, the data is more reliable and the error of the data is reduced.

[0014] Furthermore, the analysis method also includes: obtaining a third power generation of the photovoltaic cell; and obtaining the number of photovoltaic cells according to the third power generation and the first power generation; wherein the third power generation is the actual power generation of each of the photovoltaic cells.

[0015] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: in the actual operation process, the rated power generation of a photovoltaic cell is the maximum power that the component can generate under standard test conditions, but because the actual environment is not exactly the same as the standard test conditions, there will be a difference in power between the rated power generation and the actual power generation. Therefore, before determining the number of photovoltaic cells, it is necessary to predict the actual power generation of the photovoltaic cells.

[0016] Furthermore, obtaining the third power generation of the photovoltaic cell specifically includes: setting a sampling interval; setting a sampling interval according to the sampling interval; obtaining a sampling sample according to the sampling interval; obtaining a historical surface temperature of the sampling sample; and predicting the first surface temperature of the photovoltaic cell according to the historical surface temperature.

[0017] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: setting a sampling interval, setting a sampling interval according to the sampling interval, thereby obtaining a sampling sample, obtaining the historical surface temperature of the sampling sample, and predicting the surface temperature of the photovoltaic cell through the historical surface temperature. The surface temperature of the photovoltaic cell is related to the actual power generation of the photovoltaic cell. Among them, the first surface temperature is the predicted value of the surface temperature of the photovoltaic cell, which is predicted by the historical surface temperature during the future use of the photovoltaic cell.

[0018] Further, based on the historical surface temperature, the first surface temperature of the photovoltaic cell is predicted, specifically including: the first surface temperature is obtained by the following formula: T=M×α; wherein T is the surface temperature, M is the historical surface temperature, and α is the historical temperature coefficient.

[0019] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the surface temperature is obtained through a formula, which facilitates the establishment of a calculation model and makes the surface temperature data more reasonable and accurate.

[0020] Furthermore, the analysis method also includes: obtaining the historical irradiance of the sample, and predicting the third power generation of the photovoltaic cell according to the first surface temperature and the historical irradiance.

[0021] Compared with the prior art, the technical effect achieved by adopting this technical solution is that the surface temperature of the photovoltaic cell is related to the third power generation. Therefore, the actual power generation of the photovoltaic cell can be predicted by predicting the surface temperature of the photovoltaic cell.

[0022] Further, predicting the third power generation of the photovoltaic cell according to the surface temperature specifically includes: the third power generation is determined by the following formula: ; Wherein, P is the third power generation, Y 额 is the rated power generation of the photovoltaic unit, f is the photovoltaic coefficient, Q is the historical irradiance, Q 标准 is the standard irradiance, k is the temperature compensation coefficient, the temperature compensation coefficient is the compensation k value for each degree Celsius, T is the surface temperature, T 标准 is the surface temperature of the photovoltaic cell under standard conditions. Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: a calculation model is set up, and the calculation model predicts the actual power generation of photovoltaic cells through the obtained data, so that the final data on the number of photovoltaic cells is more reasonable and reliable.

[0023] Furthermore, the present invention also provides a control device, which executes the analysis method, and the control device includes: a first acquisition module, which acquires the total power consumption of the current load; a harmonic suppression module, which suppresses the first harmonic voltage; a second acquisition module, which acquires the second harmonic voltage; and a calculation module, which calculates the number of photovoltaic cells.

[0024] Compared with the prior art, the technical effect achieved by adopting the technical solution is as follows: the present invention also provides a control device, which executes the analysis method. The first acquisition module obtains the total power consumption of the current load, which can help engineers evaluate the current load and facilitate the subsequent analysis; the harmonic suppression module can suppress the harmonic voltage generated by the inverter and reduce energy loss. The second acquisition module obtains the second harmonic voltage, which is the harmonic voltage generated by the inverter after suppression. Since the harmonic suppression module cannot completely suppress the harmonic voltage, it is necessary to obtain the suppressed second harmonic voltage after suppression to increase the reliability of the analysis result. The calculation module calculates the required number of photovoltaic cells, thereby optimizing the photovoltaic power station so that the electric energy generated by the photovoltaic power station can meet the total power consumption required by the current load.

[0025] After adopting the technical solution of the present invention, the following technical effects can be achieved: (1) Obtain the total power consumption of the current load, and obtain the storage voltage based on the total power consumption so that the storage voltage can meet the voltage required by the load. The harmonic suppression module suppresses the harmonic voltage generated by the inverter to reduce energy loss, and then obtains the second harmonic voltage after the inverter is suppressed. The first power generation of the photovoltaic power station is the actual power generation. The first power generation can be obtained based on the second harmonic voltage and the storage voltage. By obtaining the first power generation, the number of photovoltaic cells can be obtained; (2) Obtain the harmonic impedance of the inverter. Based on the harmonic current and harmonic impedance, the second harmonic voltage of the inverter after suppression can be obtained. After the harmonic suppression module is activated, the harmonics of the inverter cannot be completely eliminated. Therefore, in the subsequent analysis process, it is necessary to obtain the suppressed harmonic voltage so that when obtaining the first power generation, the data is more reliable and the data error is reduced; (3) During actual operation, there will be a difference in power between the rated power generation and the actual power generation of a PV cell. Therefore, before determining the number of PV cells, it is necessary to predict the actual power generation of the PV cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A first flow chart of an analysis method provided by an embodiment of the present invention; Figure 2 The second flow chart of the analysis method. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The embodiment of the present invention provides a harmonic analysis method and control device for a multi-feed receiving-end power grid system. The photovoltaic power station includes: a photovoltaic cell, an inverter, a storage module and a harmonic suppression module. The analysis method is as shown in the attached Figure 1 As shown: S100, obtaining the total power consumption of the current load; S200, obtaining a storage voltage according to the total power consumption; S300, controlling the harmonic suppression module to suppress the first harmonic voltage of the inverter; S400, obtaining the second harmonic voltage of the inverter; S500, obtaining a first power generation amount of the photovoltaic power station according to the storage voltage and the second harmonic voltage; S600, obtaining the number of photovoltaic cells according to the first power generation; Among them, the total power consumption is the sum of the rated voltages of the loads, the storage voltage is the voltage stored in the storage module, the first harmonic voltage is the harmonic voltage before the inverter is suppressed, the second harmonic voltage is the harmonic voltage after the inverter is suppressed, and the first power generation is the actual power generation required by the photovoltaic power station.

[0029] Specifically, the total power consumption of the current load is obtained, and the storage voltage is obtained through the total power consumption. The storage voltage is greater than the total power consumption. The difference between the storage voltage and the total power consumption is used as a backup voltage to cope with emergencies in the factory; the inverter can convert the direct current generated by the photovoltaic power station into alternating current, but during the operation of the inverter, the first harmonic voltage will be generated, resulting in energy loss. The harmonic suppression module is controlled to suppress the harmonic voltage generated by the inverter to reduce the loss of electric energy. However, the harmonic suppression module cannot completely eliminate the harmonics generated by the inverter. Therefore, after suppression, the second harmonic voltage of the inverter is obtained again to increase the reliability of the analysis results. According to the second harmonic voltage and the storage voltage, the first power generation can be obtained. The first power generation is the actual power generation of the photovoltaic power station. The number of photovoltaic cells is predicted based on the actual power generation, making the predicted data more reliable.

[0030] To supplement, in the process of photovoltaic power generation, the inclination angle of the photovoltaic cells, whether there are shielding objects around the photovoltaic cells, the ambient temperature, etc. will affect the actual power generation of the photovoltaic power station. Therefore, in the process of calculating the number of photovoltaic cells, it is necessary to predict the first power generation to reduce the error in calculating the number of photovoltaic cells and improve the reliability of the analysis method.

[0031] For example, as attached Figure 2 As shown, controlling the harmonic suppression module to suppress the harmonic voltage specifically includes: S100, obtaining an input voltage of an inverter; S200, obtaining control parameters of the inverter according to the input voltage; S300, obtaining a drive pulse of the inverter according to the control parameter; Among them, after obtaining the input voltage of the inverter, the input voltage of the inverter is stepped down, and the control parameters of the inverter are obtained according to the stepped-down input voltage. In the process of obtaining the control parameters, the control parameters are obtained according to the specific working device of the inverter, so that the control parameters are more accurate and reliable. According to the control parameters, the driving pulse is obtained, and then the inverter is controlled to operate with the driving pulse.

[0032] For example, after the drive pulse of the inverter is obtained according to the control parameters, the analysis method further includes: controlling the inverter to operate with the drive pulse; and obtaining the harmonic current of the inverter.

[0033] For example, after the inverter runs with the driving pulse, a current sensor is set to detect the harmonic current of the inverter and evaluate the harmonic current of the inverter. Since the harmonic suppression device cannot completely eliminate the harmonics, the harmonic current of the inverter is obtained again after the inverter runs with the driving pulse.

[0034] Specifically, after obtaining the harmonic current of the inverter, the analysis method further includes: obtaining the harmonic impedance of the inverter, and obtaining the second harmonic voltage according to the harmonic current and the harmonic impedance.

[0035] Specifically, the second harmonic voltage is the product of the harmonic impedance and the harmonic current, and the harmonic impedance is the product of the system impedance of the inverter and n, where the harmonic order is the nth harmonic.

[0036] Specifically, the analysis method also includes: obtaining a third power generation of the photovoltaic cell; and obtaining the number of photovoltaic cells according to the third power generation and the first power generation; wherein the third power generation is the actual power generation of each photovoltaic cell.

[0037] Specifically, photovoltaic power stations generate electricity based on sunlight. There is an electrical difference between the power generation of a photovoltaic cell and the calibrated power generation. Therefore, it is necessary to predict the third power generation of the photovoltaic cell. Among them, the first power generation is the actual power generation of the photovoltaic power station, and the third power generation is the actual power generation of each photovoltaic cell, which makes the calculation result more accurate and reliable.

[0038] Specifically, obtaining the third power generation of each photovoltaic cell includes: setting a sampling interval; setting a sampling interval according to the sampling interval to obtain a sampling sample; obtaining a historical surface temperature of the sampling sample; and predicting a first surface temperature of the photovoltaic cell according to the historical surface temperature.

[0039] Specifically, a sampling interval is set, and the sampling interval is in weeks or months, such as one week or one month. A sampling interval is set within the sampling interval to obtain sampling samples, and the sampling samples are in days, such as one day or two days. This not only ensures the reliability of the sampled weather parameters, but also reduces the amount of calculation, shortens the calculation time, and improves the efficiency of the operation.

[0040] For example, the sampling interval is one week and the sampling interval is one day, then Monday, Wednesday, Friday and Sunday are sampling samples. For the sampling samples, the first time and the second time need to be set. The first time is 9 o'clock in the morning and the second time is 3 o'clock in the afternoon. During the first time to the second time, the temperature of the day is higher, so the historical surface temperature of the photovoltaic cell will also be higher. For example, the surface temperature at 9 o'clock in the morning is 39°C, the surface temperature at 10 o'clock in the morning is 40°C, the surface temperature at 11 o'clock in the morning is 42°C, the surface temperature at 12 o'clock is 50°C, the surface temperature at 1 o'clock is 50°C, the surface temperature at 2 o'clock in the afternoon is 49°C, and the surface temperature at 3 o'clock in the afternoon is 45°C. Then, the average surface temperature of the day is 45°C, and the historical surface temperature is the average surface temperature of the sampling samples.

[0041] For example, predicting the first surface temperature of the photovoltaic cell according to the historical surface temperature specifically includes: the first surface temperature is obtained by the following formula: T=M×α; wherein T is the first surface temperature, M is the historical surface temperature, and α is the historical temperature coefficient.

[0042] For example, the surface temperature is obtained through a formula, which facilitates the establishment of a calculation model, making the data of the first surface temperature more reasonable and accurate. A temperature sensor is provided on the surface of the photovoltaic cell to detect the surface temperature of the photovoltaic cell, and the surface temperature is stored as a historical surface temperature to facilitate the prediction of the surface temperature of the photovoltaic cell in the future.

[0043] Specifically, the analysis method also includes: obtaining the historical irradiance of the sample; and predicting the third power generation of the photovoltaic cell according to the first surface temperature and the historical irradiance.

[0044] Specifically, the surface temperature of the photovoltaic cell is related to the third power generation amount. Therefore, the actual power generation amount of the photovoltaic cell can be predicted by predicting the surface temperature of the photovoltaic cell.

[0045] It is supplemented that in the process of obtaining the historical irradiance of the sampling samples, the change in irradiance is close to the quadratic function image with the opening downward, which can explain that during the day, as time goes by, the irradiance first gradually increases, reaches a peak, and then gradually weakens.

[0046] For example, for the sampling sample, the first time and the second time are set. The first time is 9:00 a.m. and the second time is 3:00 p.m. During the period from the first time to the second time, the irradiance at 9:00 a.m. is 120 W / m 2 , the irradiance at 10 am is 150W / m 2 , the irradiance at 11 am is 800W / m 2 , the irradiance at 12 o'clock is 1200W / m 2 , the irradiance at 1 pm is 1200W / m 2 , the irradiance at 2 pm is 800W / m 2 , the irradiance at 3 pm is 700W / m 2 , therefore, the irradiance is 4970W / m 2 , the historical irradiance is the average irradiance of the sampled samples.

[0047] Assume that the sampling interval is seven days and the sampling interval is one day. Therefore, the irradiance of four days can be collected, and the irradiance is 4950W / m 2 , 5000W / m 2 、4830W / m 2 and 5140W / m 2 , the historical irradiance is 4980W / m 2 .

[0048] Among them, in the process of photovoltaic power generation, the light intensity needs to meet the requirements of power generation, and the light intensity is greater than 120W / m 2 Therefore, for the light intensity of the day, it is necessary to set the acquisition range to improve the reliability of the prediction results.

[0049] For example, predicting the third power generation of the photovoltaic cell according to the first surface temperature and the historical irradiance specifically includes: the third power generation is determined by the following formula: ; Among them, P is the third power generation, Y 额is the rated power generation of the photovoltaic unit, f is the photovoltaic coefficient, Q is the historical irradiance, Q 标准 is the standard irradiance, k is the temperature compensation coefficient, T is the surface temperature, T 标准 is the surface temperature of the photovoltaic cell under standard conditions.

[0050] Supplementary explanation: the standard irradiance is 1000W / m 2 Under standard conditions, the surface temperature of the photovoltaic cell is 25°C, the temperature compensation coefficient is greater than 0, the value range of the photovoltaic coefficient is between (0, 1), and the photovoltaic coefficient is related to the material of the photovoltaic cell.

[0051] For example, when a photovoltaic power station works for one day, the first power generation is 1 kWh, which is the power generation capacity of the photovoltaic power station when the light intensity is 1000W / m 2 The power generation for one day at a temperature of 25 degrees Celsius and an air quality of AM 1.5 is 4980W / m 2 , the rated power generation of the photovoltaic cell is 0.6 watt-hours, the surface temperature of the photovoltaic cell is 50°C, the temperature compensation coefficient is 0.9, and the photovoltaic coefficient is 0.1. Therefore, the third power generation of the photovoltaic cell is approximately 0.27 watt-hours.

[0052] Then the required number of photovoltaic cells is the ratio of the first power generation to the third power generation, which is 3703.7. The number of photovoltaic cells is an integer, so the required number of photovoltaic cells is 3704. Then, based on the existing photovoltaic cells in the photovoltaic power station, determine the number of photovoltaic cells that need to be added to reach 3704.

[0053] For example, a calculation model is set up, and the calculation model predicts the actual power generation of photovoltaic cells through the obtained data, so that the final data on the number of photovoltaic cells is more reasonable and reliable.

[0054] The harmonic analysis method provided by the present invention can optimize the existing photovoltaic power station when the power restriction policy is implemented in some areas, analyze the load of the factory, and obtain the total power consumption of the load. According to the total power consumption, the storage voltage is obtained, and the value of the storage voltage is greater than the value of the total power consumption. The inverter will generate harmonic voltage during operation, and the harmonic suppression module is controlled to suppress the first harmonic voltage. After suppressing the harmonic voltage, the second harmonic voltage is obtained. Since the harmonic suppression module cannot completely eliminate the first harmonic voltage, it is necessary to obtain the second harmonic voltage of the inverter again. According to the second harmonic voltage and the storage voltage, the first power generation can be obtained, wherein the first power generation is the actual power generation of the photovoltaic power station.

[0055] To further predict the actual power generation of the photovoltaic cell, the actual power generation of the photovoltaic cell is affected by the ambient temperature. Therefore, a sampling interval is set, and the sampling interval is set according to the sampling interval to obtain the sampling samples. For example, if the sampling interval is 30 days and the sampling interval is 1 day, then 15 days of sampling samples can be obtained; for the sampling samples, the first moment and the second moment are set. The first moment is 9 o'clock in the morning and the second moment is 3 o'clock in the afternoon. According to the surface temperature during this period, the average surface temperature between the first moment and the second moment is obtained, and then the average surface temperature of the sampling samples is obtained. The historical surface temperature is the average surface temperature of the sampling samples. After the historical surface temperature is obtained, the first surface temperature of the photovoltaic cell is predicted according to the calculation formula.

[0056] The third power generation of the photovoltaic cell is related to the first surface temperature and the historical irradiance. Therefore, after obtaining the sampling sample, it is also necessary to obtain the historical irradiance of the sampling sample, where the historical irradiance is the average value of the irradiance of the sampling sample. After obtaining the historical irradiance, the third power generation of the photovoltaic cell can be obtained through the calculation formula.

[0057] The ratio of the first power generation to the third power generation is the number of required photovoltaic cells. On the basis of the existing photovoltaic cells, the number of photovoltaic cells is increased so that the number of photovoltaic cells meets the number of photovoltaic cells.

[0058] The present invention also provides a control device, which executes the analysis method. The control device includes: a first acquisition module, which acquires the total power consumption of the current load; a harmonic suppression module, which suppresses the first harmonic voltage; a second acquisition module, which acquires the second harmonic voltage; and a calculation module, which calculates the number of photovoltaic cells.

[0059] Specifically, the first acquisition module obtains the total power consumption of the current load, which can help engineers evaluate the current load and facilitate subsequent analysis; the harmonic suppression module can suppress the harmonic voltage generated by the inverter and reduce energy loss. The second acquisition module obtains the second harmonic voltage. The second harmonic voltage is the harmonic voltage generated by the inverter after suppression. Since the harmonic suppression module cannot completely suppress the harmonic voltage, it is necessary to obtain the suppressed second harmonic voltage after suppression to increase the reliability of the analysis results. The calculation module calculates the required number of photovoltaic cells, thereby optimizing the photovoltaic power station so that the electric energy generated by the photovoltaic power station can meet the total power consumption required by the current load.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A harmonic analysis method for a multi-input receiving-end power grid system, the harmonic analysis method is used to control a photovoltaic power station, the photovoltaic power station includes a photovoltaic cell, an inverter, a storage module and a harmonic suppression module, characterized in that: The analysis method comprises: Get the total power consumption of the current load; deriving a storage voltage according to the total power consumption; Controlling the harmonic suppression module to suppress the first harmonic voltage of the inverter; Obtaining a second harmonic voltage of the inverter; deriving a first power generation amount of the photovoltaic power station according to the storage voltage and the second harmonic voltage; According to the first power generation, the number of the photovoltaic cells is obtained; Among them, the total power consumption is the sum of the rated voltages of the current loads, the storage voltage is the voltage stored in the power storage module, the first harmonic voltage is the harmonic voltage before the inverter is suppressed, the second harmonic voltage is the harmonic voltage after the inverter is suppressed, and the first power generation is the power generation actually required by the photovoltaic power station.

2. The harmonic analysis method according to claim 1, characterized in that: The controlling the harmonic suppression module to suppress the harmonic voltage specifically includes: Obtaining an input voltage of the inverter; According to the input voltage, a control parameter of the inverter is obtained; According to the control parameter, a driving pulse of the inverter is obtained.

3. The harmonic analysis method according to claim 2, characterized in that: After obtaining the drive pulse of the inverter according to the control parameter, the analysis method further includes: controlling the inverter to operate with the driving pulse; A harmonic current of the inverter is obtained.

4. The harmonic analysis method according to claim 1, characterized in that: After obtaining the harmonic current of the inverter, the analysis method further includes: Obtaining the harmonic impedance of the inverter; The second harmonic voltage is obtained according to the harmonic current and the harmonic impedance.

5. The harmonic analysis method according to claim 1, characterized in that: The analysis method further comprises: Obtaining a third power generation amount of the photovoltaic cell; deriving the number of the photovoltaic cells according to the third power generation and the first power generation; The third power generation is the actual power generation of each photovoltaic cell.

6. The harmonic analysis method according to claim 5, characterized in that: The obtaining of the third power generation amount of the photovoltaic cell specifically includes: Set the sampling interval; According to the sampling interval, set the sampling interval time; According to the sampling interval, a sampling sample is obtained; Obtaining a historical surface temperature of the sample; A first surface temperature of the photovoltaic cell is predicted based on the historical surface temperature.

7. The harmonic analysis method according to claim 6, characterized in that: The predicting the first surface temperature of the photovoltaic cell according to the historical surface temperature specifically includes: The first surface temperature is obtained by the following formula: T = M × α; Wherein, T is the first surface temperature, M is the historical surface temperature, and α is the historical temperature coefficient.

8. The harmonic analysis method according to claim 7, characterized in that: The analysis method further comprises: Obtaining the historical irradiance of the sample; A third power generation amount of the photovoltaic cell is predicted according to the first surface temperature and the historical irradiance.

9. The harmonic analysis method according to claim 8, characterized in that: The predicting, according to the first surface temperature and the historical irradiance, a third power generation of the photovoltaic cell specifically includes: The third power generation amount is determined by the following formula: ； Wherein, P is the third power generation, Y 额 is the rated power generation of the photovoltaic cell, f is the photovoltaic coefficient, Q is the historical irradiance, Q 标准 is the standard irradiance, k is the temperature compensation coefficient, T is the surface temperature, T 标准 is the surface temperature of the photovoltaic cell under standard conditions.

10. A control device, wherein the control device controls the execution of the harmonic analysis method according to any one of claims 1 to 9, characterized in that: The control device comprises: A first acquisition module, wherein the first acquisition module acquires the total power consumption of the current load; A harmonic suppression module, wherein the harmonic suppression module suppresses the first harmonic voltage; A second acquisition module, wherein the second acquisition module acquires the second harmonic voltage; A calculation module is used to calculate the number of the photovoltaic cells.

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