Optical storage power control method and system

Abstract

The present invention relates to an optical storage power control method and system. Related electrical parameters, such as output voltage and output current, of a fuel generator are acquired, accordingly, the current real-time power transmission power or real-time operating frequency of the fuel generator is calculated, and whether the fuel generator outputs power or power is inputted to the fuel generator is determined on the basis of the current power flow direction state, to determine whether the fuel generator is in an abnormal state. When it is identified that reverse flow to the fuel generator occurs or is about to occur, the absolute output of output power of an inverter is controlled to be reduced, so as to increase the absolute output of output power of the fuel generator, avoiding reverse flow; and when it is identified that a power overload occurs in the fuel generator, the absolute output of the output power of the inverter is controlled to be increased, so as to reduce the absolute output of the output power of the fuel generator, avoiding the overload of the fuel generator. Therefore, the protection of the fuel generator can be achieved, it is ensured that a load can operate stably, and the service life of the fuel generator and the load is prolonged.

Description

A method and system for controlling optical storage power Technical Field

[0001] The present invention relates to the field of photovoltaic control technology, and in particular to a photovoltaic storage power control method and system. Background Art

[0002] A photovoltaic storage system is a power generation system that utilizes solar energy and is composed of solar panels made of special materials such as crystalline silicon panels, inverters, and other electronic components. It can be connected to the power grid or fuel generators for stable power transmission. When the photovoltaic storage system operates in an off-grid environment, there are situations where the photovoltaic storage inverter and the fuel generator operate simultaneously, such as when the fuel generator remains connected while the load is powered on. When the inverter and fuel generator operate simultaneously, the fuel generator acts as a generator, outputting power and ensuring the stability of the output voltage frequency and amplitude, thereby ensuring the normal operation of the load, ensuring the stable operation of the power generation equipment, and extending the service life.

[0003] In a photovoltaic storage system, when the inverter and fuel generator are working at the same time, the power required by the external load will change, which will cause the required power supply to change. During this process, if no special control is taken, the fuel generator will experience abnormal operating conditions such as backflow or overload.

[0004] Reverse flow: Reverse power flow occurs when the generator's output power reverses, meaning external power is input into the generator. This is an abnormal operating condition and is generally not permitted. In this abnormal reverse flow condition, there is a risk that the inverter's output power will flow back into the generator. This can cause the generator to function as a motor, potentially causing overspeed and increasing the generator's output voltage and frequency, potentially damaging the load.

[0005] Overload: A fuel generator's output power exceeds its capacity, an abnormal operating condition that is generally not permitted. In this abnormal overload condition, there is a risk of the generator overloading. At this time, the generator's output power exceeds its capacity, and the generator's speed may be reduced, resulting in a decrease in the generator's output voltage and frequency, which can cause damage to the load and other problems.

[0006] Therefore, how to control the photovoltaic power storage according to specific working conditions and thus protect the fuel generator is the technical problem that this application aims to solve.

[0007] Summary of the Invention

[0008] A main purpose of the present invention is to overcome at least one of the above-mentioned defects, and to provide a method and system for controlling solar power storage, which can solve the problems of power reverse flow and power overload of fuel generators, ensure the stability of load power supply voltage, ensure the stable operation of fuel generators, and improve the service life of the equipment.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] The present invention provides a photovoltaic power storage control method for a working condition where a photovoltaic power generation system and a fuel generator jointly supply power to a load. The output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the power load to supply power to the power load. The method includes:

[0011] S1: Detecting the power transmission status of the fuel generator;

[0012] S2: Compare the detected power transmission status parameters with pre-configured thresholds and determine the operating status of the fuel generator based on the comparison results;

[0013] S3: When it is determined that the fuel generator is in an abnormal working state, adjusting the output power of the inverter and restoring the fuel generator to a normal working state.

[0014] According to one embodiment of the present invention, the preconfigured thresholds include a reverse flow threshold and an overload threshold. The reverse flow threshold is used to determine the reverse flow abnormal state of the fuel generator, and the overload threshold is used to determine the overload abnormal state of the fuel generator.

[0015] According to one embodiment of the present invention, the reverse flow threshold is a reverse flow power threshold or a reverse flow frequency threshold. When performing step S2, the real-time transmission power or real-time operating frequency of the fuel generator is calculated based on the detected transmission state parameter, or the real-time operating frequency is calculated based on the state signal fed back by the fuel generator. By comparing the real-time transmission power with the reverse flow power threshold, it is determined whether the fuel generator is in an abnormal reverse flow state, or by comparing the real-time operating frequency with the reverse flow frequency threshold, it is determined whether the fuel generator is in an abnormal reverse flow state.

[0016] According to one embodiment of the present invention, the sign of the power consumption of the electric load is defined as positive, the sign of the output power of the inverter and the fuel generator is defined as positive, and the reverse flow threshold is selected as the reverse flow power threshold. When the real-time transmission power is less than the reverse flow power threshold, it is determined that the fuel generator is in a reverse flow abnormal state, and the output power of the inverter is controlled to increase.

[0017] According to one embodiment of the present invention, the reverse flow power threshold is 5% to 10% of the absolute value of the rated power of the fuel generator, which is a negative number.

[0018] According to one embodiment of the present invention, during the process of reducing the output power of the inverter when the fuel generator is in a reverse flow abnormal state,

[0019] According to the deviation between the minimum allowable operating power of the fuel generator and the real-time transmission power, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0020] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0021] According to one embodiment of the present invention, the sign of the power consumption of the electric load is defined as positive, the sign of the output power of the inverter and the fuel generator is defined as negative and positive, and the reverse flow threshold is selected as the reverse flow frequency threshold. When the real-time operating frequency is greater than the reverse flow frequency threshold, it is determined that the fuel generator is in a reverse flow abnormal state, and the output power of the inverter is controlled to be reduced.

[0022] According to one embodiment of the present invention, the reverse flow frequency threshold is 105% to 110% of the rated frequency of the fuel generator.

[0023] According to one embodiment of the present invention, during the process of reducing the output power of the inverter when the fuel generator is in a reverse flow abnormal state,

[0024] According to the deviation between the maximum allowed operating frequency of the fuel generator and the real-time operating frequency, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0025] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0026] According to one embodiment of the present invention, in step S1, the transmission voltage and transmission current of the fuel generator are detected in real time, and the real-time transmission power or real-time operating frequency is calculated based on the real-time transmission voltage and transmission current, or the real-time operating frequency is calculated based on a status signal fed back by the fuel generator.

[0027] According to one embodiment of the present invention, the overload threshold is an overload power threshold or an overload frequency threshold. When performing step S2, the real-time transmission power or real-time operating frequency of the fuel generator is calculated based on the detected transmission status parameter, or the real-time operating frequency is calculated based on the status signal fed back by the fuel generator. By comparing the real-time transmission power with the overload power threshold, it is determined whether the fuel generator is in an abnormal overload state, or by comparing the real-time operating frequency with the overload frequency threshold, it is determined whether the fuel generator is in an abnormal overload state.

[0028] According to one embodiment of the present invention, the sign of the power consumption of the electric load is defined as positive, the sign of the output power of the inverter and the fuel generator is defined as positive, and the overload threshold is selected as the overload power threshold. When the real-time transmission power is greater than the overload power threshold, it is determined that the fuel generator is in an abnormal overload state, and the output power of the inverter is controlled to increase.

[0029] According to one embodiment of the present invention, the overload power threshold is 105% to 110% of the rated power of the fuel generator, which is a positive number.

[0030] According to one embodiment of the present invention, in the process of increasing the output power of the inverter when the fuel generator is in an abnormal overload state,

[0031] According to the deviation between the maximum allowable operating power of the fuel generator and the real-time transmission power, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0032] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0033] According to one embodiment of the present invention, the sign of the power consumption of the electric load is defined as positive, the sign of the output power of the inverter and the fuel generator is defined as positive, and the overload threshold is selected as the overload frequency threshold. When the real-time operating frequency is less than the overload frequency threshold, it is determined that the fuel generator is in an abnormal overload state, and the output power of the inverter is controlled to increase.

[0034] According to one embodiment of the present invention, the overload frequency threshold is 90% to 95% of the rated frequency of the fuel generator.

[0035] According to one embodiment of the present invention, during the process of reducing the output power of the inverter when the fuel generator is in an abnormal overload state,

[0036] According to the deviation between the minimum allowable operating frequency of the fuel generator and the real-time operating frequency, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0037] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0038] According to one embodiment of the present invention, in step S1, the transmission voltage of the fuel generator is detected in real time, and the real-time operating frequency of the fuel generator is obtained through voltage phase-locked processing based on the real-time transmission voltage, or the real-time operating frequency is calculated based on a status signal fed back by the fuel generator.

[0039] According to one embodiment of the present invention, the fuel generator is an adaptive generator. In step S3, after the output power of the inverter is controlled and adjusted, the fuel generator adaptively adjusts the output power.

[0040] According to one embodiment of the present invention, in step S3, after the output power of the inverter is controlled and adjusted, the output power of the fuel generator is adjusted according to the total power of the power load and the output power of the inverter until the output power of the fuel generator is restored to the output power under normal working conditions.

[0041] In particular, the present invention further provides a photovoltaic power storage control system for use in a working condition where a photovoltaic power generation system and a fuel generator jointly power a load, wherein the output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the electrical load to power the electrical load, and the photovoltaic power storage control system includes:

[0042] A fuel generator data acquisition module, wherein a sampling input end is electrically connected to an output phase line of the fuel generator, and a sampling output end is connected to an input end of a fuel generator power calculation module;

[0043] A fuel generator power calculation module, wherein the output end of the fuel generator power calculation module is connected to the input end of the inverter power control module;

[0044] an inverter power control module, the inverter power control module being communicatively connected to the inverter;

[0045] The inverter power control module sends an inverter power control instruction to the inverter according to the real-time power of the fuel generator, so as to control and adjust the output power of the inverter.

[0046] According to one embodiment of the present invention, the fuel generator power calculation module calculates power based on voltage and current signals.

[0047] According to one embodiment of the present invention, the inverter power control module is communicatively connected to the fuel generator.

[0048] In particular, the present invention further provides a photovoltaic power storage control system for use in a working condition where a photovoltaic power generation system and a fuel generator jointly power a load, wherein the output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the electrical load to power the electrical load, and the photovoltaic power storage control system includes:

[0049] a communication module, one side of which is in communication connection with the fuel generator, and the other side of which is in communication connection with the frequency calculation module;

[0050] a frequency calculation module, which obtains the status signal of the fuel generator through the communication module and calculates the real-time operating frequency of the fuel generator according to the status signal, and the output end of the frequency calculation module is connected to the inverter power control module;

[0051] an inverter power control module, communicatively connected to the inverter;

[0052] The inverter power control module sends an inverter power control instruction to the inverter according to the real-time operating frequency of the fuel generator, so as to control and adjust the output power of the inverter.

[0053] According to one embodiment of the present invention, the status signal of the fuel generator is a rotation speed signal or a rotation frequency signal of the fuel generator.

[0054] Compared with the prior art, the advantages and beneficial effects of the photovoltaic storage power control method and system of the present invention are:

[0055] The photovoltaic power control method and system of the present application obtains relevant electrical parameters of the fuel generator, such as output voltage and output current, and calculates the current real-time transmission power or real-time operating frequency of the fuel generator based on these parameters. It then determines whether the fuel generator is outputting power or inputting power based on the current power flow state, thereby distinguishing abnormal states of the fuel generator. When it is identified that the fuel generator is experiencing reverse flow or is about to experience reverse flow, the inverter is controlled to reduce the absolute output power, thereby increasing the absolute output power of the fuel generator and avoiding reverse flow. When it is identified that the fuel generator is experiencing power overload, the inverter is controlled to increase the absolute output power, thereby reducing the absolute output power of the fuel generator and avoiding overload of the fuel generator. Therefore, it is possible to protect the fuel generator while ensuring that the load can operate stably, thereby increasing the service life of the fuel generator and the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0057] FIG1 is a schematic diagram of a reverse flow discrimination process in a method for controlling solar storage power according to an embodiment of the present invention;

[0058] 2 is a schematic diagram of power changes during reverse current identification and regulation in a method for controlling solar power storage according to an embodiment of the present invention;

[0059] 3 is a schematic diagram of a reverse flow identification process in a method for controlling solar storage power according to another embodiment of the present invention;

[0060] 4 is a schematic diagram of an overload determination process in a method for controlling optical storage power according to an embodiment of the present invention;

[0061] 5 is a schematic diagram of power changes during overload identification and regulation in a method for controlling solar power storage according to an embodiment of the present invention;

[0062] 6 is a schematic diagram of an overload determination process in a method for controlling optical storage power according to another embodiment of the present invention;

[0063] 7 is a block diagram of a photovoltaic power storage control system according to an embodiment of the present invention;

[0064] FIG8 is a structural block diagram of a photovoltaic power storage control system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0065] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0066] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0067] This application describes a photovoltaic power storage control method for a working condition where a photovoltaic power generation system and a fuel-fired generator (diesel engine) jointly power a load. The output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel-fired generator are simultaneously connected to the power load to power the power load, including:

[0068] S1: Detecting the power transmission status of the fuel generator;

[0069] S2: Compare the detected power transmission status parameters with pre-configured thresholds and determine the operating status of the fuel generator based on the comparison results;

[0070] S3: When it is determined that the fuel generator is in an abnormal working state, adjusting the output power of the inverter and restoring the fuel generator to a normal working state.

[0071] The photovoltaic power control method of the present application obtains the relevant electrical parameters of the fuel generator, such as output voltage and output current, and calculates the current real-time transmission power or real-time operating frequency of the fuel generator based on this. It then determines whether the fuel generator is outputting power or inputting power based on the current power flow state, thereby distinguishing the abnormal state of the fuel generator. When it is identified that the fuel generator has reverse flow or is about to reverse flow, the inverter is controlled to reduce the absolute output power, thereby increasing the absolute output power of the fuel generator and avoiding reverse flow; when it is identified that the fuel generator has power overload, the inverter is controlled to increase the absolute output power, thereby reducing the absolute output power of the fuel generator and avoiding overload of the fuel generator. Therefore, it is possible to protect the fuel generator while ensuring that the load can operate stably and prolong the service life of the fuel generator and the load.

[0072] The abnormal operating conditions addressed by this application are reverse flow and overload, and the corresponding thresholds are reverse flow and overload thresholds. Specifically, the reverse flow threshold is used to determine if the fuel generator is in a reverse flow state, and the overload threshold is used to determine if the fuel generator is in an overload state. The following describes two specific methods for addressing these two abnormal conditions.

[0073] The sign of power consumed by electrical loads is defined as positive; the sign of power output by inverters and fuel generators is also positive. The absolute output power of an inverter refers to the absolute value of the inverter's output power and is a positive number; the absolute output power of a fuel generator refers to the absolute value of the generator's output power and is a positive number.

[0074] Example 1:

[0075] In this embodiment, the configured reverse flow threshold is a reverse flow power threshold. When performing step S2, the real-time transmission power of the fuel generator is calculated based on the detected transmission state parameters. By comparing the real-time transmission power with the reverse flow power threshold, it is determined whether the fuel generator is in an abnormal reverse flow state. The reverse flow threshold is selected as the reverse flow power threshold. When the real-time transmission power is less than the reverse flow power threshold, it is determined that the fuel generator is in an abnormal reverse flow state, and the output power of the inverter is controlled to be reduced.

[0076] When the fuel generator is in an abnormal reverse flow state, it means that the absolute output of the inverter's output power is too large, resulting in reverse flow in the fuel generator. At this time, it is necessary to reduce the absolute output of the inverter's output power to allow the fuel generator to escape the reverse flow state and resume normal operation.

[0077] In one embodiment, the reverse flow power threshold is a negative number, ranging from 5% to 10% of the absolute value of the rated power of the fuel-fired generator. In this embodiment, the rated power of the fuel-fired generator is 400 kW, and the reverse flow power threshold is preconfigured to be 5% of the absolute value of the rated power of the fuel-fired generator, i.e., the reverse flow power threshold is -20 kW. This indicates that the reverse flow power threshold in this embodiment is a negative number, meaning that in the reverse flow state, the fuel-fired generator becomes an electric motor, becoming an electrical load and consuming power.

[0078] As shown in Figure 1, the reverse flow identification process calculates the real-time transmission power P of the fuel generator based on the collected output voltage U and current I of the fuel generator. gen , according to the real-time transmission power P gen and reverse power threshold P thd1 The comparison is used to judge whether the fuel generator has entered the abnormal reverse flow state. When the real-time transmission power P gen ≤Reverse power threshold P thd1 When the reverse flow is detected or tends to occur, the reverse flow is determined to occur. After the fuel generator is determined to be in the reverse flow abnormal state, the output power of the inverter is controlled to be reduced, and the power of the fuel generator is then increased to return to a positive value, thereby restoring the power output state and overcoming the reverse flow abnormal state.

[0079] The power variation during the countercurrent identification and regulation process shown in this embodiment is shown in FIG2 , and is specifically described as follows:

[0080] During the period from time 0 to t1, the load power P load Relatively stable, provided by the fuel generator and inverter, the load consumes power P load =Fuel ​​generator output power P gen +Inverter output power P inv ;

[0081] Starting from t1, the load consumes power P load Reduced, but the inverter output power P inv Basically unchanged, the absolute output power of the fuel generator P gen reduce;

[0082] At time t2, the output power of the fuel-fired generator is P gen When the power is less than 0 and reaches below -20 kW, it can be determined that a reverse flow abnormality has occurred, and a power reduction instruction is sent to the inverter to control and reduce the output power of the inverter;

[0083] The inverter then reduces the output power P inv , corresponding to the absolute output power P of the fuel generator gen It rebounds and there is no countercurrent trend anymore. By time t3, the output power of the fuel generator and the inverter is redistributed, and the photovoltaic storage system of the fuel generator reaches a new stable state.

[0084] In one embodiment, when the fuel generator is in a reverse flow abnormal state and the output power of the inverter is reduced,

[0085] According to the deviation between the minimum allowable operating power of the fuel generator and the real-time transmission power, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0086] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0087] The minimum operating power P of the fuel generator genMin Pre-configured, it can be configured as a fixed value, such as 0.5kw, or it can be set as a range curve; the real-time output power of the fuel generator is P gen (t)).

[0088] The process of determining the inverter power command output for controlling the inverter power change by the PID controller includes the following steps:

[0089] First calculate the minimum operating power P of the fuel generator genMin and real-time output power P gen (t) The real-time power deviation P between genDelta (t), the real-time power deviation P genDelta The calculation formula for (t) is P genDelta (t) = P genMin (t)-P gen (t)

[0090] Then, the above real-time power deviation P genDelta (t) Calculate the proportion (P), integral (I), and differential (D) and sum them to get the PID control output, that is, the inverter power control instruction P invRef (t), the specific calculation formula is:

[0091] In practice, the three parameters K p , K i , K d Carry out debugging and adjustment according to the actual control effect.

[0092] Example 2:

[0093] The photovoltaic power storage control method of this embodiment is adjusted based on Example 1. The difference is that the reverse flow threshold is a reverse flow frequency threshold. When performing step S2, the real-time operating frequency of the fuel generator is calculated based on the detected power transmission state parameters, or the real-time operating frequency is calculated based on the state signal fed back by the fuel generator. By comparing the real-time operating frequency with the reverse flow frequency threshold, it is determined whether the fuel generator is in an abnormal reverse flow state.

[0094] The real-time operating frequency of the fuel generator can be calculated based on the output voltage of the fuel generator through a voltage phase-locked method, or based on a state signal such as a rotation speed or a rotation frequency fed back by the fuel generator.

[0095] The fuel generator in this embodiment is a single-phase generator, and its output voltage waveform is a sine wave or a quasi-sine wave. This output voltage signal is recorded as U a , then U b Perform signal processing to construct a signal U that is 90° ahead of its phase b , and then adjust U according to the phase-locking angle a 、U b After Park transformation, we get U d 、U q , U d 、U q The expression for the transformation is as follows:

[0096] Where θ is the output angle of the phase-locked calculation;

[0097] Will U q As input, PID control is performed, and its output is angular velocity ω. The real-time operating frequency of the fuel generator is ω / 2π.

[0098] The process of calculating the real-time operating frequency based on the status signal fed back by a fuel-powered generator is based on the speed signal or rotational frequency signal fed back by the generator. The speed of a fuel-powered generator is proportional to its real-time operating frequency, so the real-time operating frequency can be inferred from the speed signal or rotational frequency signal fed back by the generator. For example, the frequency f of a fuel-powered generator is calculated as: number of magnetic pole pairs * speed / 60. For example, a diesel generator has two magnetic pole pairs and an engine speed of 1500 rpm, so the frequency f = 2 * 1500 / 60 = 50 Hz. For example, a domestically produced steam turbine generator has only one magnetic pole pair and a generator speed of 3000 rpm, so the frequency f = 1 * 3000 / 60 = 50 Hz. Therefore, by monitoring the speed and rotational frequency of a fuel-powered generator, its real-time operating frequency can be detected.

[0099] By identifying the frequency of the fuel generator, it is indirectly possible to determine whether the fuel generator is in an abnormal reverse flow state. When a fuel generator experiences reverse flow, the motor in the fuel generator is in electric mode, and its speed will be difficult to control, resulting in overspeed, causing the frequency of the fuel generator output voltage to increase. Therefore, by calculating the frequency of the fuel generator output voltage, it is possible to determine whether the fuel generator is in a reverse flow state.

[0100] In one embodiment, the reverse flow frequency threshold is 105% to 110% of the absolute value of the rated frequency of the fuel generator. In this embodiment, the rated frequency of the fuel generator is 50 Hz, and the reverse flow frequency threshold f thd1 Pre-configured to 105% of the rated frequency of the fuel-fired generator, i.e. 52.5 Hz.

[0101] As shown in Figure 3, the reverse flow identification process calculates the real-time operating frequency f of the fuel generator based on the collected fuel generator output voltage U. gen , according to the real-time operating frequency f gen and the countercurrent frequency threshold f thd1 The comparison is used to judge whether the fuel generator has entered the abnormal reverse flow state. When the real-time operating frequency f gen ≥Backflow frequency threshold f thd1 After determining that the fuel generator is in an abnormal reverse flow state, the output power of the inverter is controlled to be reduced.

[0102] In one embodiment, during the process of reducing the output power of the inverter when the fuel generator is in a reverse flow abnormal state,

[0103] According to the deviation between the maximum allowed operating frequency of the fuel generator and the real-time operating frequency, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0104] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0105] The maximum operating frequency f of the fuel generator genMax Pre-configured, it can be configured as a fixed value, such as 52Hz, or it can be set as a range curve; the real-time operating frequency of the fuel generator is calculated according to the output voltage of the fuel generator, and the real-time operating frequency is recorded as f gen (t).

[0106] The process of determining the inverter power command output for controlling the inverter power change by the PID controller includes the following steps:

[0107] First calculate the maximum operating frequency f of the fuel generator genMax and real-time operating frequency f gen (t) The real-time frequency deviation f between genDelta (t), the real-time frequency deviation f genDelta The calculation formula for (t) is P genDelta (t) = f genMax (t)-f gen (t)

[0108] Then, the above real-time frequency deviation f genDelta (t) Calculate the proportion (P), integral (I), and differential (D) and sum them to get the PID control output, that is, the inverter power control instruction P invRef (t), the specific calculation formula is:

[0109] In practice, the three parameters K p , K i , K d It can be debugged and adjusted according to the actual control effect.

[0110] Those skilled in the art will appreciate that, in other embodiments, both the reverse flow power threshold and the reverse flow frequency threshold may be selected simultaneously, and the reverse flow abnormal state may be determined simultaneously based on the two parameters, thereby improving the accuracy of the determination.

[0111] Example 3:

[0112] In this embodiment, the configured overload threshold is an overload power threshold. When performing step S2, the real-time transmission power of the fuel generator is calculated based on the detected transmission state parameter. By comparing the real-time transmission power with the overload power threshold, it is determined whether the fuel generator is in an abnormal overload state. The overload threshold is selected as the overload power threshold. When the real-time transmission power is greater than the overload power threshold, it is determined that the fuel generator is in an abnormal overload state, and the output power of the inverter is controlled to be reduced.

[0113] In one embodiment, the overload power threshold is a positive number between 105% and 110% of the rated power of the fuel generator. In this embodiment, the rated power of the fuel generator is 400 kW, and the overload power threshold is preconfigured to 105% of the rated power of the fuel generator, that is, the overload power threshold is 420 kW.

[0114] As shown in Figure 4, the overload judgment process calculates the real-time transmission power P of the fuel generator based on the collected output voltage U and current I of the fuel generator. gen , according to the real-time transmission power P gen and overload power threshold P thd2 The comparison is used to judge whether the fuel generator has entered an abnormal overload state. When the real-time transmission power P gen ≥Overload power threshold P thd2 When it is determined that the fuel generator is in an abnormal overload state, the output power of the inverter is increased.

[0115] The power change during the overload identification and regulation process shown in this embodiment is shown in FIG5 , and is specifically described as follows:

[0116] During the period from time 0 to t1, the load power P load Relatively stable, provided by the fuel generator and inverter, the load consumes power P load =Fuel ​​generator output power P gen +Inverter output power P inv ;

[0117] Starting from t1, the load consumes power P load Improve, but the output power P of the inverter inv Basically unchanged, the output power P of the fuel generator gen improve;

[0118] At time t2, the output power of the fuel generator is P genThe maximum capacity of the fuel generator is exceeded, reaching 420kw. At this time, it can be determined that an overload abnormality has occurred, so a power reduction instruction is sent to the inverter to control the reduction of the output power of the inverter;

[0119] The inverter then increases the output power P inv , corresponding to the output power P of the fuel generator gen The power consumption of the fuel generator decreases and there is no overload trend anymore. At t3, the output power of the fuel generator and the inverter is redistributed, and the photovoltaic storage system of the fuel generator reaches a new stable state.

[0120] In one embodiment, when the fuel generator is in an abnormal overload state and the output power of the inverter is increased,

[0121] According to the deviation between the maximum allowable operating power of the fuel generator and the real-time transmission power, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0122] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0123] The maximum operating power P of the fuel generator genMax Pre-configured, it can be configured as a fixed value, such as 410kw, or it can be set as a range curve; the real-time output power of the fuel generator is P gen (t).

[0124] The process of determining the inverter power command output for controlling the inverter power change by the PID controller includes the following steps:

[0125] First calculate the maximum operating power P of the fuel generator genMax and real-time output power P gen (t) The real-time power deviation P between genDelta (t), the real-time power deviation P genDelta The calculation formula for (t) is P genDelta (t) = P genMax (t)-P gen (t)

[0126] Then, the above real-time power deviation P genDelta (t) Calculate the proportion (P), integral (I), and differential (D) and sum them to get the PID control output, that is, the inverter power control instruction P invRef (t), the specific calculation formula is:

[0127] In practice, the three parameters K p , K i , K d Carry out debugging and adjustment according to the actual control effect.

[0128] Example 4:

[0129] The photovoltaic power storage control method of this embodiment is an adjustment based on Example 3, differing in that the overload threshold is an overload frequency threshold. During step S2, the real-time operating frequency of the fuel-fired generator is calculated based on the detected power transmission state parameter, or based on a status signal fed back by the fuel-fired generator. The real-time operating frequency is compared with the overload frequency threshold to determine whether the fuel-fired generator is in an abnormal overload state. When the real-time operating frequency is less than the overload frequency threshold, the fuel-fired generator is determined to be in an abnormal overload state, and the inverter output power is controlled to be reduced.

[0130] In other words, by identifying the frequency of the fuel-fired generator, it is indirectly possible to determine whether the generator is in an abnormal overload state. When a fuel-fired generator is overloaded, its output power exceeds its capacity, making its speed difficult to control. Therefore, it will slow down, causing the frequency of the generator's output voltage to decrease. Therefore, by calculating the frequency of the generator's output voltage, it can be used to determine whether the generator is overloaded.

[0131] In one embodiment, the overload frequency threshold is 90% to 95% of the rated frequency of the fuel generator. In this embodiment, the rated frequency of the fuel generator is 50 Hz, and the overload frequency threshold f thd2 Pre-configured to 95% of the rated frequency of the fuel generator, i.e. 47.5Hz.

[0132] As shown in Figure 6, the overload judgment process calculates the real-time operating frequency f of the fuel generator based on the collected fuel generator output voltage U. gen , according to the real-time operating frequency f gen and overload frequency threshold f thd2 The comparison is used to judge whether the fuel generator has entered an abnormal overload state. When the real-time operating frequency f gen ≤Overload frequency threshold f thd2 When it is determined that the fuel generator is in an abnormal overload state, the output power of the inverter is increased.

[0133] In one embodiment, when the fuel generator is in an abnormal overload state and the output power of the inverter is controlled to increase,

[0134] According to the deviation between the minimum allowable operating frequency of the fuel generator and the real-time operating frequency, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is:

[0135] where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

[0136] The minimum operating frequency f of the fuel generator genMin Pre-configured, it can be configured as a fixed value, such as 48Hz, or it can be set as a range curve; the real-time operating frequency of the fuel generator is calculated according to the output voltage of the fuel generator, and the real-time operating frequency is recorded as f gen (t).

[0137] The process of determining the inverter power command output for controlling the inverter power change by the PID controller includes the following steps:

[0138] First calculate the minimum operating frequency f of the fuel generator genMin and real-time operating frequency f gen (t) The real-time frequency deviation f between genDelta (t), the real-time frequency deviation f genDelta The calculation formula for (t) is P genDelta (t) = f genmin (t)-f gen (t)

[0139] Then, the above real-time frequency deviation f genDelta (t) Calculate the proportion (P), integral (I), and differential (D) and sum them to get the PID control output, that is, the inverter power control instruction P invRef (t), the specific calculation formula is:

[0140] In practice, the three parameters K p , K i , K d It can be debugged and adjusted according to the actual control effect.

[0141] Those skilled in the art will appreciate that, in other embodiments, both the overload power threshold and the overload frequency threshold may be selected simultaneously, and the overload abnormal state may be determined based on the two parameters, thereby improving the accuracy of the determination.

[0142] In addition, in other embodiments, any two, three or four parameters among the reverse current power threshold, reverse current frequency threshold, overload power threshold and overload frequency threshold can be selected, and the reverse current abnormal state and / or overload abnormal state can be judged simultaneously based on this, thereby achieving diversified detection and improving judgment accuracy.

[0143] Example 5:

[0144] The present invention also provides a photovoltaic power storage control system for use in a working condition where a photovoltaic power generation system and a fuel generator are connected to the grid for power supply. The output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the power load to supply power to the power load. As shown in FIG7 , the photovoltaic power storage control system includes:

[0145] A fuel generator data acquisition module, wherein a sampling input end is electrically connected to an output phase line of the fuel generator, and a sampling output end is connected to an input end of a fuel generator power calculation module;

[0146] A fuel generator power calculation module, wherein the output end of the fuel generator power calculation module is connected to the input end of the inverter power control module;

[0147] an inverter power control module, the inverter power control module being communicatively connected to the inverter;

[0148] The inverter power control module sends an inverter power control instruction to the inverter according to the real-time power of the fuel generator, so as to control and adjust the output power of the inverter.

[0149] In one embodiment, the fuel generator power calculation module calculates power based on voltage and current signals.

[0150] In one embodiment, the inverter power control module is communicatively connected to the fuel generator.

[0151] The photovoltaic power storage control system of this embodiment obtains relevant electrical parameters of the fuel generator, such as output voltage and output current, through the fuel generator data acquisition module, and calculates the current real-time transmission power or real-time operating frequency of the fuel generator in the fuel generator power calculation module based on this. It determines whether the fuel generator is power output or power input based on the current power flow state. Finally, it realizes the judgment of the abnormal state of the fuel generator in the inverter power control module and generates the corresponding inverter power control instruction according to the type of abnormal state.

[0152] When the system detects reverse flow or an imminent reverse flow in the fuel generator, it controls the inverter to reduce output power, thereby increasing the generator's output power and preventing reverse flow. When the system detects a power overload in the fuel generator, it controls the inverter to increase output power, thereby reducing the generator's output power and preventing overload. This protects the fuel generator while ensuring stable operation of the load, extending the lifespan of the generator and the load.

[0153] Example 6:

[0154] This embodiment provides a photovoltaic power storage control system for a working condition where a photovoltaic power generation system and a fuel generator jointly power a load. The output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the electrical load to supply power to the electrical load. As shown in FIG8 , the photovoltaic power storage control system includes:

[0155] a communication module, one side of which is in communication connection with the fuel generator, and the other side of which is in communication connection with the frequency calculation module;

[0156] a frequency calculation module, which obtains the status signal of the fuel generator through the communication module and calculates the real-time operating frequency of the fuel generator according to the status signal, and the output end of the frequency calculation module is connected to the inverter power control module;

[0157] an inverter power control module, communicatively connected to the inverter;

[0158] The inverter power control module sends an inverter power control instruction to the inverter according to the real-time operating frequency of the fuel generator, so as to control and adjust the output power of the inverter.

[0159] The state signal of the fuel generator is a rotation speed signal or a rotation frequency signal of the fuel generator.

[0160] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling photovoltaic power storage, used in a working condition where a photovoltaic power generation system and a fuel generator jointly supply power to a load, wherein the output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the power load to supply power to the power load, characterized in that: include: S1: Detecting the power transmission status of the fuel generator; S2: comparing the detected power transmission state parameter with a pre-configured threshold value, and judging the working state of the fuel generator according to the comparison result; S3: When it is determined that the fuel generator is in an abnormal working state, the output power of the inverter is adjusted to restore the fuel generator to a normal working state.

2. The method for controlling the photovoltaic power storage according to claim 1, characterized in that: The preconfigured thresholds include a backflow threshold and an overload threshold. The backflow threshold is used to determine the backflow abnormal state of the fuel generator, and the overload threshold is used to determine the overload abnormal state of the fuel generator.

3. The method for controlling the photovoltaic power storage according to claim 2, characterized in that: The reverse flow threshold is a reverse flow power threshold or a reverse flow frequency threshold. When performing step S2, the real-time transmission power or real-time operating frequency of the fuel generator is calculated according to the detected transmission state parameter, or the real-time operating frequency is calculated according to the state signal fed back by the fuel generator. By comparing the real-time transmission power with the reverse flow power threshold, it is determined whether the fuel generator is in a reverse flow abnormal state, or by comparing the real-time operating frequency with the reverse flow frequency threshold, it is determined whether the fuel generator is in a reverse flow abnormal state.

4. The method for controlling the photovoltaic power storage according to claim 3, characterized in that: The power consumption sign of the electric load is defined as positive, the output power sign of the inverter and the fuel generator is defined as positive, the reverse flow threshold is selected as the reverse flow power threshold, and when the real-time transmission power is less than the reverse flow power threshold, it is determined that the fuel generator is in a reverse flow abnormal state, and the output power of the inverter is controlled to be reduced.

5. The method for controlling the photovoltaic power storage according to claim 4, characterized in that: The reverse flow power threshold is 5% to 10% of the absolute value of the rated power of the fuel generator, which is a negative number.

6. The method for controlling the photovoltaic power storage according to claim 4, characterized in that: In the process of reducing the output power of the inverter when the fuel generator is in a reverse flow abnormal state, According to the deviation between the minimum allowable operating power of the fuel generator and the real-time transmission power, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is: Among them, K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

7. The method for controlling the photovoltaic power storage according to claim 3, characterized in that: The power consumption sign of the electric load is defined as positive, the output power sign of the inverter and the fuel generator is defined as positive, the reverse flow threshold is selected as the reverse flow frequency threshold, and when the real-time operating frequency is greater than the reverse flow frequency threshold, it is determined that the fuel generator is in a reverse flow abnormal state, and the output power of the inverter is controlled to increase.

8. The method for controlling the photovoltaic power storage according to claim 7, characterized in that: The reverse flow frequency threshold is 105% to 110% of the rated frequency of the fuel generator.

9. The method for controlling the photovoltaic power storage according to claim 7, characterized in that: In the process of reducing the output power of the inverter when the fuel generator is in a reverse flow abnormal state, According to the deviation between the maximum allowable operating frequency of the fuel generator and the real-time operating frequency, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is: Where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

10. The method for controlling the photovoltaic power according to any one of claims 3 to 9, characterized in that: In step S1, the transmission voltage and transmission current of the fuel generator are detected in real time, and the real-time transmission power or real-time operating frequency is calculated according to the real-time transmission voltage and transmission current, or the real-time operating frequency is calculated according to the status signal fed back by the fuel generator.

11. The method for controlling the photovoltaic power storage according to claim 2, characterized in that: The overload threshold is an overload power threshold or an overload frequency threshold. When performing step S2, the real-time transmission power or real-time operating frequency of the fuel generator is calculated according to the detected transmission state parameter, or the real-time operating frequency is calculated according to the state signal fed back by the fuel generator. By comparing the real-time transmission power with the overload power threshold, it is determined whether the fuel generator is in an abnormal overload state, or by comparing the real-time operating frequency with the overload frequency threshold, it is determined whether the fuel generator is in an abnormal overload state.

12. The method for controlling the photovoltaic power storage according to claim 10, characterized in that: The power consumption sign of the electric load is defined as positive, the output power sign of the inverter and the fuel generator is defined as positive, the overload threshold is selected as the overload power threshold, and when the real-time transmission power is greater than the overload power threshold, it is determined that the fuel generator is in an abnormal overload state, and the output power of the inverter is controlled to increase.

13. The method for controlling the photovoltaic power storage according to claim 12, characterized in that: The overload power threshold is 105% to 110% of the rated power of the fuel generator, and is a positive number.

14. The method for controlling the photovoltaic power storage according to claim 12, characterized in that: In the process of increasing the output power of the inverter when the fuel generator is in an abnormal overload state, According to the deviation between the maximum allowable operating power of the fuel generator and the real-time transmission power, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is: Where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

15. The method for controlling the photovoltaic power storage according to claim 11, characterized in that: The power consumption sign of the electric load is defined as positive, the output power sign of the inverter and the fuel generator is defined as positive, the overload threshold is selected as the overload frequency threshold, and when the real-time operating frequency is less than the overload frequency threshold, it is determined that the fuel generator is in an abnormal overload state, and the output power of the inverter is controlled to increase.

16. The method for controlling the photovoltaic power storage according to claim 15, characterized in that: The overload frequency threshold is 90% to 95% of the rated frequency of the fuel generator.

17. The method for controlling the photovoltaic power storage according to claim 15, characterized in that: In the process of increasing the output power of the inverter when the fuel generator is in an abnormal overload state, According to the deviation between the minimum allowable operating frequency of the fuel generator and the real-time operating frequency, the PID controller is used to calculate and output the inverter power instruction. The transfer function of the PID controller is: Where K p is the proportional adjustment coefficient, K i is the integral adjustment coefficient, K d is the differential adjustment coefficient, and S is a complex variable.

18. The method for controlling the photovoltaic power according to any one of claims 11 to 17, characterized in that: In step S1, the transmission voltage of the fuel generator is detected in real time, and the real-time operating frequency of the fuel generator is obtained through voltage phase-locked processing according to the real-time transmission voltage, or the real-time operating frequency is calculated according to a state signal fed back by the fuel generator.

19. The method for controlling the photovoltaic power storage according to claim 1, characterized in that: The fuel generator is an adaptive generator. In step S3, after the output power of the inverter is controlled and adjusted, the fuel generator adaptively adjusts the output power.

20. The method for controlling the photovoltaic power storage according to claim 1, characterized in that: In step S3, after the output power of the inverter is controlled and adjusted, the output power of the fuel generator is adjusted according to the total power of the power load and the output power of the inverter until the output power of the fuel generator is restored to the output power under normal working conditions.

21. A photovoltaic power storage control system, used in the working condition where a photovoltaic power generation system and a fuel generator jointly supply power to a load, the output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the power load to supply power to the power load, characterized in that: The photovoltaic power storage control system includes: A fuel generator data acquisition module, wherein a sampling input end is electrically connected to an output phase line of the fuel generator, and a sampling output end is connected to an input end of a fuel generator power calculation module; A fuel generator power calculation module, wherein the output end of the fuel generator power calculation module is connected to the input end of the inverter power control module; An inverter power control module, the inverter power control module is communicatively connected with the inverter; The inverter power control module sends an inverter power control instruction to the inverter according to the real-time power of the fuel generator, so as to control and adjust the output power of the inverter.

22. The photovoltaic power storage control system according to claim 21, characterized in that: The fuel generator power calculation module calculates the power according to the voltage and current signals.

23. The photovoltaic power storage control system according to claim 21, characterized in that: The inverter power control module is in communication connection with the fuel generator.

24. A photovoltaic power storage control system, used in a working condition where a photovoltaic power generation system and a fuel generator jointly supply power to a load, wherein the output phase line of the inverter of the photovoltaic power generation system and the output phase line of the fuel generator are simultaneously connected to the power load to supply power to the power load, characterized in that: The photovoltaic power storage control system includes: A communication module, one side of which is connected to the fuel generator for communication, and the other side of which is connected to the frequency calculation module for communication; A frequency calculation module, which obtains the status signal of the fuel generator through the communication module and calculates the real-time operating frequency of the fuel generator according to the status signal, and the output end of the frequency calculation module is connected to the inverter power control module; An inverter power control module, communicatively connected to the inverter; The inverter power control module sends an inverter power control instruction to the inverter according to the real-time operating frequency of the fuel generator, so as to control and adjust the output power of the inverter.

25. The photovoltaic power storage control system according to claim 24, characterized in that: The state signal of the fuel generator is a rotation speed signal or a rotation frequency signal of the fuel generator.

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