Photovoltaic active power regulation and control-based power distribution network light storage cooperation electric energy quality improvement method

Abstract

The invention provides a photovoltaic active power regulation and control-based power distribution network light storage cooperation electric energy quality improvement method, which comprises the following steps of: obtaining a bus voltage fluctuation range coefficient and a rated bus voltage to obtain a bus voltage lower limit, and comparing a bus voltage actual value with the bus voltage lower limit; if the actual value of the bus voltage is smaller than the lower limit of the bus voltage, reducing the photovoltaic reference power and updating the photovoltaic reference voltage when the photovoltaic module does not work in the maximum power point tracking mode; if the bus voltage actual value is greater than or equal to the bus voltage lower limit, adjusting the photovoltaic reference power and updating the photovoltaic reference voltage based on the charge state actual value of the energy storage unit, the charge state charging critical value, the bus voltage actual value and the rated bus voltage; and generating a driving signal through photovoltaic active power regulation and control based on the photovoltaic output voltage, the bus voltage actual value and the updated photovoltaic reference voltage so as to regulate and control the optical storage system. By using the method of the invention, photovoltaic dominated voltage fluctuation suppression can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power control and power quality, and in particular to a method for improving power quality of a distribution network by photovoltaic-storage synergy based on photovoltaic active power regulation. Background Art

[0002] As the global demand for renewable energy continues to increase, photovoltaic power generation has attracted much attention as a clean and sustainable form of energy. The continuous innovation of photovoltaic technology and the continuous decline in costs have made photovoltaic power generation one of the preferred energy sources in more and more countries and regions. In such an environment, the photovoltaic industry has developed rapidly, not only driving the vigorous development of related industrial chains, but also providing important support for global energy transformation. Photovoltaic power generation systems can be divided into two types: centralized and distributed according to the installation method. Distributed photovoltaics have higher flexibility and can increase or decrease the number of photovoltaic modules at any time as needed. They are suitable for occasions with decentralized energy demand and have received widespread attention. However, because photovoltaic power fluctuates in real time with changes in the external environment, a high proportion of distributed photovoltaic access causes the power quality of the distribution network to deteriorate, and voltage fluctuations and harmonics exceed the standard frequently occur.

[0003] In order to suppress the voltage fluctuation problem of distribution network caused by the random volatility of large-scale photovoltaic output power and improve the power quality of distribution network, researchers have proposed to further increase energy storage capacity or add special power quality management equipment. However, electrochemical energy storage devices are expensive, have short lifespans, and have low return on investment. Special power quality management equipment is expensive, has short working hours after addition, has low utilization, and is difficult to deploy widely.

[0004] Compared with further adding energy storage and power quality management equipment, controlling the power reduction mode of photovoltaic work to a certain extent to mobilize the flexibility of photovoltaic is a feasible way under the condition of increasingly lower photovoltaic power generation costs. Existing distributed photovoltaics mostly work in maximum power point tracking mode to maximize the use of photovoltaic power. Photovoltaics working in maximum power point tracking mode in real time do not respond to system requirements. Photovoltaics working in flexible power point tracking mode release huge regulation potential by reducing the active power output. Studies have shown that the application of flexible power point tracking method can realize constant power control, power standby control, power slope control and other adjustable functions. By flexibly switching between various functions, the flexibility of photovoltaic power generation in responding to system requirements can be significantly improved, and photovoltaic active support can be realized. However, the existing photovoltaic active support methods are mostly based on the basic perturbation observation method, and the application scenarios are mostly large power grids, which cannot adapt to distributed photovoltaic scenarios. In addition, the distribution network working conditions are relatively complex, and rapid changes in light and load fluctuations often occur. Existing methods are difficult to effectively solve these problems.

[0005] In summary, with the increasing proportion of new energy represented by distributed photovoltaics, the efficient and stable operation of distribution networks faces huge challenges. Existing solutions cannot take into account the contradiction between cost and effect, and cannot handle complex working conditions. Therefore, it is urgent to propose new solutions to the voltage fluctuation problem to improve the safety, stability and economy of the system under complex working conditions. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, the first objective of the present invention is to propose a method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power regulation, so as to achieve photovoltaic-dominated voltage fluctuation suppression.

[0008] The second object of the present invention is to propose a distribution network photovoltaic storage collaborative power quality improvement system based on photovoltaic active power regulation.

[0009] A third objective of the present invention is to provide an electronic device.

[0010] A fourth object of the present invention is to provide a computer-readable storage medium.

[0011] To achieve the above-mentioned purpose, the first aspect of the present invention proposes a method for improving power quality of distribution network photovoltaic storage synergy based on photovoltaic active power control, comprising:

[0012] Obtaining a bus voltage fluctuation range coefficient and a rated bus voltage to obtain a bus voltage lower limit, and comparing an actual bus voltage value with the bus voltage lower limit;

[0013] If the actual bus voltage value is less than the bus voltage lower limit, then when the photovoltaic module is not operating in the maximum power point tracking mode, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated;

[0014] If the actual bus voltage value is greater than or equal to the bus voltage lower limit, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual state of charge value of the energy storage unit, the state of charge charging threshold value, the actual bus voltage value and the rated bus voltage;

[0015] Based on the photovoltaic output voltage, the actual value of the bus voltage and the updated photovoltaic reference voltage, a driving signal is generated through photovoltaic active power regulation to regulate the photovoltaic storage system.

[0016] The method of the first aspect of the present invention also includes: when the actual value of the bus voltage is less than the bus voltage lower limit and the photovoltaic component operates in the maximum power point tracking mode, controlling the energy storage unit to discharge to control the bus voltage to the rated bus voltage.

[0017] In the method of the first aspect of the present invention, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the state of charge of the energy storage unit, the state of charge charging critical value, the actual value of the bus voltage and the rated bus voltage, including: if the actual value of the state of charge is less than the state of charge charging critical value, the photovoltaic component is operated in the maximum power point tracking mode and the energy storage unit is controlled to charge; if the actual value of the state of charge is greater than or equal to the state of charge charging critical value, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the bus voltage and the rated bus voltage.

[0018] In the method of the first aspect of the present invention, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the bus voltage and the rated bus voltage, including: if the actual value of the bus voltage is less than the rated bus voltage, the photovoltaic reference power is increased and the photovoltaic reference voltage is updated; if the actual value of the bus voltage is greater than or equal to the rated bus voltage, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated.

[0019] To achieve the above-mentioned purpose, the second aspect of the present invention proposes a distribution network photovoltaic storage coordinated power quality improvement system based on photovoltaic active power control, comprising:

[0020] A judgment processing module, used for obtaining the bus voltage fluctuation range coefficient and the rated bus voltage to obtain the bus voltage lower limit, and comparing the bus voltage actual value with the bus voltage lower limit;

[0021] A first control module is used for reducing the photovoltaic reference power and updating the photovoltaic reference voltage when the photovoltaic module is not operating in the maximum power point tracking mode if the actual value of the bus voltage is less than the lower limit of the bus voltage;

[0022] A second control module is used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the state of charge of the energy storage unit, the charging threshold of the state of charge, the actual value of the bus voltage and the rated bus voltage if the actual value of the bus voltage is greater than or equal to the lower limit of the bus voltage;

[0023] The third control module is used to generate a driving signal through photovoltaic active power control based on the photovoltaic output voltage, the actual value of the bus voltage, and the updated photovoltaic reference voltage to control the photovoltaic storage system.

[0024] In the system of the second aspect of the present invention, the first regulation module is also used to: when the actual value of the bus voltage is less than the lower limit of the bus voltage and the photovoltaic component operates in the maximum power point tracking mode, control the energy storage unit to discharge to control the bus voltage to the rated bus voltage.

[0025] In the system of the second aspect of the present invention, the second control module, when used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the state of charge of the energy storage unit, the state of charge charging threshold, the actual value of the bus voltage and the rated bus voltage, is specifically used to: if the actual value of the state of charge is less than the state of charge charging threshold, then operate the photovoltaic component in the maximum power point tracking mode and control the charging of the energy storage unit; if the actual value of the state of charge is greater than or equal to the state of charge charging threshold, then adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the bus voltage and the rated bus voltage.

[0026] In the system of the second aspect of the present invention, the second control module, when used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the bus voltage and the rated bus voltage, is specifically used to: if the actual value of the bus voltage is less than the rated bus voltage, increase the photovoltaic reference power and update the photovoltaic reference voltage; if the actual value of the bus voltage is greater than or equal to the rated bus voltage, reduce the photovoltaic reference power and update the photovoltaic reference voltage.

[0027] To achieve the above-mentioned purpose, the third aspect of the present invention proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method proposed in the first aspect of the present invention.

[0028] To achieve the above-mentioned purpose, the fourth aspect of the present invention proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method proposed in the first aspect of the present invention.

[0029] The method, system, electronic device and storage medium for improving power quality of photovoltaic-storage synergistic power distribution network based on photovoltaic active power regulation provided by the present invention obtain the bus voltage lower limit by acquiring the bus voltage fluctuation range coefficient and the rated bus voltage, and compare the actual bus voltage value with the bus voltage lower limit; if the actual bus voltage value is less than the bus voltage lower limit, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated when the photovoltaic module is not operating in the maximum power point tracking mode; if the actual bus voltage value is greater than or equal to the bus voltage lower limit, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the state of charge of the energy storage unit, the state of charge charging critical value, the actual value of the bus voltage and the rated bus voltage; a driving signal is generated through photovoltaic active power regulation based on the photovoltaic output voltage, the actual value of the bus voltage and the updated photovoltaic reference voltage to regulate the photovoltaic storage system. In this case, the bus voltage fluctuation range coefficient, rated bus voltage and actual bus voltage value are comprehensively considered to adjust the PV reference power and update the PV reference voltage according to different situations. Then, the PV output voltage and actual bus voltage value are combined to generate a driving signal through PV active power regulation to regulate the photovoltaic storage system, thereby suppressing voltage fluctuations. In this way, PV-dominated voltage fluctuation suppression is achieved.

[0030] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0032] Figure 1 A schematic diagram of a photovoltaic storage system connected to a distribution network provided by an embodiment of the present invention;

[0033] Figure 2 A topological diagram of a photovoltaic active power support converter provided by an embodiment of the present invention;

[0034] Figure 3 A control architecture diagram of a photovoltaic active power support converter provided by an embodiment of the present invention;

[0035] Figure 4 A schematic flow chart of a method for improving power quality of a distribution network by synergizing photovoltaic storage based on photovoltaic active power control provided by an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of a specific process of a method for improving power quality of a distribution network by synergizing photovoltaic storage with active photovoltaic power control provided by an embodiment of the present invention;

[0037] Figure 6A schematic diagram of another photovoltaic storage system connected to a distribution network provided by an embodiment of the present invention;

[0038] Figure 7 A block diagram of a distribution network photovoltaic storage collaborative power quality improvement system based on photovoltaic active power control provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0040] The following describes a method and system for improving power quality of distribution network photovoltaic-storage collaboration based on photovoltaic active power control according to an embodiment of the present invention with reference to the accompanying drawings.

[0041] It is easy to understand that the method and system for improving power quality of distribution network photovoltaic storage collaboration based on photovoltaic active power regulation involved in the present invention are suitable for photovoltaic storage systems.

[0042] The following is an explanation of the photovoltaic energy storage system with reference to the accompanying drawings. Figure 1 A schematic diagram of a photovoltaic storage system connected to a distribution network provided by an embodiment of the present invention. Figure 2 This is a topology diagram of a photovoltaic active power support converter provided in an embodiment of the present invention. Figure 3 This is a control architecture diagram of a photovoltaic active power support converter provided in an embodiment of the present invention.

[0043] like Figure 1 As shown, the photovoltaic storage system includes photovoltaic components, active power regulation converters, energy storage units, energy storage converters, and loads. The photovoltaic components are connected to the low-voltage bus through the active power regulation converter, the energy storage unit is connected to the low-voltage bus through the energy storage converter, and the low-voltage bus is also connected to the load. The low-voltage bus is connected to the load through the first transformer T 1 , low voltage to medium voltage line impedance L 1 The medium voltage bus is also connected to a second transformer T 2 .

[0044] The active power control converter provided by the present invention is also called a photovoltaic active power support converter. Figure 2 As shown, the active power control converter includes Figure 2 The converter shown in (a) and Figure 2 The sampling circuit, active power control loop and driving circuit shown in (b) are shown in FIG. Figure 2The converter shown in (a) includes a photovoltaic output capacitor Cpv, a DC-DC converter, a DC bus capacitor Cdc, a DC-AC converter, a first filter inductor L f1 , the second filter inductor L f2 , the third filter inductor L f3 The input end of the converter is connected to the photovoltaic module, and the output end is connected to the low-voltage bus. Cp is the grounding capacitor.

[0045] When the active power control converter is working, the sampling circuit is used to collect the photovoltaic output voltage Vpv and photovoltaic output current Ipv on the photovoltaic side, and collect the bus voltage Vpcc of the low-voltage bus on the bus side, and transmit them to the active power control loop. The active power control loop takes the photovoltaic output voltage, photovoltaic output current and bus voltage of the low-voltage bus collected by the sampling circuit as input, and takes the PWM waveform as output. The drive circuit amplifies the PWM (Pulse Width Modulation Wave, a pulse with variable duty cycle) waveform output by the digital controller to regulate the DC-DC converter and DC-AC converter, thereby realizing photovoltaic active power control.

[0046] The active power control loop includes a control loop of a DC-DC converter and a control loop of a DC-AC converter.

[0047] Among them, the input of the control loop of the DC-DC converter is the photovoltaic output voltage and photovoltaic output current. First, the photovoltaic reference voltage Vref is generated by the photovoltaic active power control method, and then the voltage deviation is obtained by comparing the photovoltaic reference voltage with the actual photovoltaic output voltage, and the deviation is used as the input of the corresponding PI regulator (Proportional-Integral Controller). The output of the PI regulator is used as the input of the digital pulse width modulator to output a PWM waveform. The drive circuit generates a corresponding time-varying DC-DC converter drive signal by power amplifying the PWM waveform output by the digital controller to regulate the DC-DC converter.

[0048] The input of the control loop of the DC-AC converter includes the bus voltage of the low-voltage bus, the actual voltage Vdc of the DC bus capacitor, the reference voltage Vdcref of the DC bus capacitor and the reactive power value Q. The control loop of the DC-AC converter includes an outer loop and an inner loop, wherein the outer loop realizes the constant voltage of the DC bus, and the outer loop calculates the reactive power reference value Qref based on the photovoltaic reference voltage Vref and the bus voltage Vpcc through a subtractor and a feedback function f(i), calculates the difference between the reactive power reference value Qref and the reactive power value Q, and uses the difference as the input of the corresponding PI regulator to obtain the current reference value iqref for controlling reactive power; the outer loop also obtains the current reference value idref for controlling active power based on the actual voltage Vdc of the DC bus capacitor and the reference voltage Vdcref of the DC bus capacitor through a corresponding subtractor and a PI regulator, and the inner loop obtains the corresponding PWM waveform based on the current reference value iqref for controlling reactive power and the current reference value idref for controlling active power through a current controller. The drive circuit amplifies the power of the PWM waveform output by the digital controller to generate a corresponding time-varying DC-AC converter drive signal to regulate the DC-AC converter.

[0049] Active power regulation based on converters can achieve active power regulation. However, with the increasing proportion of new energy represented by distributed photovoltaics, the efficient and stable operation of distribution networks faces huge challenges. Existing solutions cannot take into account the contradiction between cost and effect, and cannot handle complex working conditions. Therefore, it is urgent to propose new solutions to the voltage fluctuation problem to improve the safety, stability and economy of the system under complex working conditions.

[0050] Based on this, an embodiment of the present invention provides a method for improving power quality of distribution network photovoltaic storage collaboration based on photovoltaic active power regulation to achieve photovoltaic-dominated voltage fluctuation suppression.

[0051] Figure 4 A schematic flow chart of a method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power control provided by an embodiment of the present invention.

[0052] like Figure 4 As shown, the method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power regulation includes the following steps:

[0053] Step S101, obtaining the bus voltage fluctuation range coefficient and the rated bus voltage to obtain the bus voltage lower limit, and comparing the bus voltage actual value with the bus voltage lower limit.

[0054] In step S101, the bus voltage lower limit is (1-μ)V oL . Where μ is the bus voltage fluctuation range coefficient. V oL is the rated bus voltage.

[0055] Step S102: if the actual bus voltage value is less than the bus voltage lower limit, then when the photovoltaic module is not operating in the maximum power point tracking mode, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated.

[0056] In step S102, it also includes: when the actual value of the bus voltage is less than the lower limit of the bus voltage and the photovoltaic assembly operates in the maximum power point tracking mode, controlling the energy storage unit to discharge to control the bus voltage to the rated bus voltage.

[0057] Step S103, if the actual bus voltage value is greater than or equal to the bus voltage lower limit, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual state of charge value of the energy storage unit, the state of charge charging threshold, the actual bus voltage value and the rated bus voltage.

[0058] In step S103, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the state of charge of the energy storage unit, the critical value of the state of charge charging, the actual value of the bus voltage and the rated bus voltage, including: if the actual value of the state of charge is less than the critical value of the state of charge charging, the photovoltaic component is operated in the maximum power point tracking mode and the energy storage unit is controlled to charge; if the actual value of the state of charge is greater than or equal to the critical value of the state of charge charging, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the bus voltage and the rated bus voltage. Among them, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the bus voltage and the rated bus voltage, including: if the actual value of the bus voltage is less than the rated bus voltage, the photovoltaic reference power is increased and the photovoltaic reference voltage is updated; if the actual value of the bus voltage is greater than or equal to the rated bus voltage, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated.

[0059] Step S104, generating a driving signal through photovoltaic active power regulation based on the photovoltaic output voltage, the actual value of the bus voltage, and the updated photovoltaic reference voltage to regulate the photovoltaic storage system.

[0060] In step S104, the photovoltaic output voltage, the actual value of the bus voltage (i.e., the collected bus voltage Vpcc), and the updated photovoltaic reference voltage are sent to the active power control converter to generate a drive signal through photovoltaic active power control to control the photovoltaic storage system. In this case, compared with the traditional photovoltaic active power control method to generate the photovoltaic reference voltage Vref, the updated photovoltaic reference voltage reduces the impact of voltage fluctuations, thereby achieving photovoltaic-dominated voltage fluctuation suppression.

[0061] In some embodiments, Figure 5 A schematic diagram of a specific process of a method for improving power quality of a distribution network by photovoltaic-storage collaboration based on photovoltaic active power control provided by an embodiment of the present invention.

[0062] like Figure 5 As shown, when the active power control converter is working (i.e., when actively supporting), in order to suppress voltage fluctuations, the distribution network photovoltaic storage coordinated power quality improvement method based on photovoltaic active power control includes:

[0063] First, the system is initialized and real-time data is collected. The initialization process includes: setting the initial value of the reference power, the initial value of the photovoltaic output power, the initial value of the photovoltaic reference voltage, the bus voltage fluctuation range coefficient, the initial value of the energy storage unit charge state, clearing the voltage and current sampling data, and the rated bus voltage V oL , State of Charge (SoC) th Etc. Real-time data collection includes the actual value of bus voltage and the actual value of state of charge SoC, and then:

[0064] Step 1): Read the bus voltage fluctuation range coefficient μ and the rated bus voltage V oL , calculate the bus voltage upper limit (1+μ)V oL and bus voltage lower limit (1-μ)V oL , collect the photovoltaic output voltage Vpv, photovoltaic output current Ipv, bus voltage actual value V L , where the photovoltaic output voltage at the nth sampling point is V pv (n), the photovoltaic output current at the nth sampling point is I pv (n), the actual bus voltage value at the nth sampling point is V pcc (n), calculate the photovoltaic power P pv (n) = V pv (n)×I pv (n). Among them, n is the sampling point index, the bus voltage fluctuation range coefficient μ can be 0.05 to 0.1, and the collected photovoltaic output voltage and photovoltaic output current are the average values ​​within the sampling period. The sampling period is generally selected from 0.1s to 1s based on the specific situation.

[0065] Step 2): The actual bus voltage value V pcc (n) and bus voltage upper limit (1+μ)V oL and bus voltage lower limit (1-μ)V oL For comparison. pcc (n)>(1+μ)V oL , jump to step 3, if (1-μ)V oL ≤V pcc (n)≤(1+μ)V oL , jump to step 3, if V pcc (n)<(1-μ)V oL , skip to step 4.

[0066] Step 3): Collect the actual value SoC of the state of charge of the energy storage unit. If SoC < SoC th , the photovoltaic system operates in the maximum power point tracking mode (MPPT), controls the energy storage unit to charge, and controls the low voltage bus voltage to the rated bus voltage through the energy storage unit until the SoC reaches the SoC th Then jump to step 5). Among them, the state of charge charging threshold value SoC th It can be 0.9 to 0.95. The actual value SoC of the state of charge of the energy storage unit collected can be estimated according to the output voltage and current of the energy storage unit.

[0067] Step 4): Determine whether the photovoltaic module is working in the maximum power point tracking mode. If so (i.e., working MPPT), keep the photovoltaic module working in the maximum power point tracking mode, control the energy storage unit to discharge, and control the low-voltage bus voltage to the rated bus voltage through the energy storage unit. Among them, the maximum power point tracking mode is realized by classical maximum power point tracking methods such as the perturbation observation method, and the low-voltage bus voltage is controlled by the energy storage unit through double closed-loop control. If it is not working in MPPT, reduce the photovoltaic reference power and jump to step 6).

[0068] Step 5): Compare V pcc (n) and V oL , if [V pcc (n)-V oL ]≥0, reduce the PV reference power and jump to step 6). If [V pcc (n)-V oL ]<0, increase the PV reference power and jump to step 7).

[0069] Step 6): Update the photovoltaic reference voltage, i.e. V pv (n+1)=P pv (n+1) / I pv (n), let V pv (n+1) is the updated photovoltaic reference voltage Vref 更新 , return to step 2). The calculation method for updating the photovoltaic reference voltage is based on the photovoltaic output characteristic that there is an approximate constant current region on the left side of the maximum power point.

[0070] Step 7): Use the maximum power point tracking method to update the photovoltaic reference voltage until the maximum power point tracking is achieved and then return to step 2).

[0071] Using the updated photovoltaic reference voltage Vref obtained above 更新 , combined with the actual values ​​of the photovoltaic output voltage and bus voltage, a driving signal is generated through photovoltaic active power control to regulate the photovoltaic storage system, thereby suppressing voltage fluctuations. In this way, photovoltaic-dominated voltage fluctuation suppression is achieved.

[0072] Figure 6 A schematic diagram of another photovoltaic storage system connected to a distribution network provided by an embodiment of the present invention. Figure 6 The figure shows the situation of multi-PV energy storage coordination. Figure 6 As shown in Figure 1, there are N photovoltaic modules, each of which is connected to the low-voltage busbar through a corresponding active power control converter. The process of multi-photovoltaic energy storage coordination is similar to the above Figure 1 The single photovoltaic energy storage coordination shown is basically the same, the difference is that when reducing the photovoltaic reference power, it is achieved through multi-photovoltaic coordinated power reduction, and the distribution of the power reduction can adopt different distribution strategies such as average distribution or droop distribution based on the difference in its own capacity.

[0073] In order to implement the above-mentioned embodiments, the present invention also proposes a distribution network photovoltaic storage collaborative power quality improvement system based on photovoltaic active power regulation.

[0074] Figure 7 A block diagram of a distribution network photovoltaic storage collaborative power quality improvement system based on photovoltaic active power control provided by an embodiment of the present invention.

[0075] like Figure 7 As shown, the distribution network photovoltaic storage collaborative power quality improvement system based on photovoltaic active power control includes a judgment processing module 11, a first control module 12, a second control module 13 and a third control module 14, wherein:

[0076] A judgment processing module 11 is used to obtain the bus voltage fluctuation range coefficient and the rated bus voltage to obtain the bus voltage lower limit, and compare the bus voltage actual value with the bus voltage lower limit;

[0077] A first regulating module 12 is configured to reduce the photovoltaic reference power and update the photovoltaic reference voltage when the photovoltaic module is not operating in the maximum power point tracking mode if the actual value of the bus voltage is less than the lower limit of the bus voltage;

[0078] A second control module 13 is used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the state of charge of the energy storage unit, the charging threshold value of the state of charge, the actual value of the bus voltage and the rated bus voltage if the actual value of the bus voltage is greater than or equal to the lower limit of the bus voltage;

[0079] The third control module 14 is used to generate a driving signal through photovoltaic active power control based on the photovoltaic output voltage, the actual value of the bus voltage, and the updated photovoltaic reference voltage to control the photovoltaic storage system.

[0080] Furthermore, in a possible implementation of an embodiment of the present invention, the first control module 12 is also used to: when the actual value of the bus voltage is less than the lower limit of the bus voltage and the photovoltaic component operates in the maximum power point tracking mode, control the energy storage unit to discharge to control the bus voltage to the rated bus voltage.

[0081] Furthermore, in a possible implementation of an embodiment of the present invention, the second control module 13, when used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the state of charge of the energy storage unit, the state of charge charging critical value, the actual value of the bus voltage and the rated bus voltage, is specifically used to: if the actual value of the state of charge is less than the state of charge charging critical value, operate the photovoltaic component in the maximum power point tracking mode and control the charging of the energy storage unit; if the actual value of the state of charge is greater than or equal to the state of charge charging critical value, adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the bus voltage and the rated bus voltage.

[0082] Furthermore, in a possible implementation of an embodiment of the present invention, the second control module 13, when used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the bus voltage and the rated bus voltage, is specifically used to: if the actual value of the bus voltage is less than the rated bus voltage, increase the photovoltaic reference power and update the photovoltaic reference voltage; if the actual value of the bus voltage is greater than or equal to the rated bus voltage, reduce the photovoltaic reference power and update the photovoltaic reference voltage.

[0083] It should be noted that the aforementioned explanation of the embodiment of the method for improving the power quality of distribution network photovoltaic storage collaborative power based on photovoltaic active power regulation is also applicable to the distribution network photovoltaic storage collaborative power quality improvement system based on photovoltaic active power regulation in this embodiment, and will not be repeated here.

[0084] In the embodiment of the present invention, the bus voltage fluctuation range coefficient and the rated bus voltage are obtained to obtain the bus voltage lower limit, and the bus voltage actual value is compared with the bus voltage lower limit; if the bus voltage actual value is less than the bus voltage lower limit, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated when the photovoltaic module is not working in the maximum power point tracking mode; if the bus voltage actual value is greater than or equal to the bus voltage lower limit, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual value of the state of charge of the energy storage unit, the state of charge charging critical value, the bus voltage actual value and the rated bus voltage; based on the photovoltaic output voltage, the bus voltage actual value, and the updated photovoltaic reference voltage, a driving signal is generated through photovoltaic active power regulation to regulate the photovoltaic storage system. In this case, the bus voltage fluctuation range coefficient, the rated bus voltage, and the actual bus voltage are comprehensively considered to adjust the photovoltaic reference power and update the photovoltaic reference voltage according to different situations, and then the photovoltaic output voltage and the actual bus voltage are combined to generate a driving signal through photovoltaic active power regulation to regulate the photovoltaic storage system, thereby suppressing the voltage fluctuation, thereby realizing the photovoltaic-dominated voltage fluctuation suppression, thereby improving the power quality.

[0085] The method and system of the present invention have the following beneficial effects: 1) Optimizing the photovoltaic reference voltage and suppressing voltage fluctuations through photovoltaic active power regulation has cost advantages compared to adding dedicated power quality management equipment. 2) Under the premise of small range fluctuations in load voltage, photovoltaic active power regulation is used to achieve approximate stability of load voltage, reduce the number of times energy storage participates in system charging and discharging, and optimize the life of energy storage units.

[0086] In order to implement the above embodiments, the present invention also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0087] In order to implement the above embodiments, the present invention further proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0088] In order to implement the above embodiments, the present invention further provides a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0089] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0090] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0091] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0092] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0093] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0094] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0095] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0096] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power regulation, characterized in that: include: Obtaining a bus voltage fluctuation range coefficient and a rated bus voltage to obtain a bus voltage lower limit, and comparing an actual bus voltage value with the bus voltage lower limit; If the actual bus voltage value is less than the bus voltage lower limit, then when the photovoltaic module is not operating in the maximum power point tracking mode, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated; If the actual bus voltage value is greater than or equal to the lower limit of the bus voltage, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual state of charge value of the energy storage unit, the state of charge charging threshold value, the actual bus voltage value and the rated bus voltage; Based on the photovoltaic output voltage, the actual value of the bus voltage and the updated photovoltaic reference voltage, a driving signal is generated through photovoltaic active power regulation to regulate the photovoltaic storage system.

2. The method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power control according to claim 1 is characterized in that: Also includes: When the actual bus voltage value is less than the bus voltage lower limit and the photovoltaic assembly operates in a maximum power point tracking mode, the energy storage unit is controlled to discharge to control the bus voltage to a rated bus voltage.

3. The method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power control according to claim 1 is characterized in that: The method of adjusting the photovoltaic reference power and updating the photovoltaic reference voltage based on the actual state of charge value of the energy storage unit, the critical value of the state of charge, the actual value of the bus voltage and the rated bus voltage includes: If the actual state of charge value is less than the critical value of the state of charge, the photovoltaic module is operated in a maximum power point tracking mode and the energy storage unit is controlled to charge; If the actual state of charge value is greater than or equal to the state of charge charging threshold value, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual bus voltage value and the rated bus voltage.

4. The method for improving power quality of distribution network photovoltaic storage synergistically based on photovoltaic active power control according to claim 3 is characterized in that: The method of adjusting the photovoltaic reference power and updating the photovoltaic reference voltage based on the actual bus voltage value and the rated bus voltage includes: If the actual bus voltage value is less than the rated bus voltage, the photovoltaic reference power is increased and the photovoltaic reference voltage is updated; If the actual bus voltage value is greater than or equal to the rated bus voltage, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated.

5. A distribution network photovoltaic storage coordinated power quality improvement system based on photovoltaic active power control, characterized in that: include: A judgment processing module, used for obtaining a bus voltage fluctuation range coefficient and a rated bus voltage to obtain a bus voltage lower limit, and comparing an actual bus voltage value with the bus voltage lower limit; A first control module is used for reducing the photovoltaic reference power and updating the photovoltaic reference voltage when the photovoltaic module is not operating in the maximum power point tracking mode if the actual value of the bus voltage is less than the lower limit of the bus voltage; A second control module is used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual value of the state of charge of the energy storage unit, the charging threshold of the state of charge, the actual value of the bus voltage and the rated bus voltage if the actual value of the bus voltage is greater than or equal to the lower limit of the bus voltage; The third control module is used to generate a driving signal through photovoltaic active power control based on the photovoltaic output voltage, the actual value of the bus voltage, and the updated photovoltaic reference voltage to control the photovoltaic storage system.

6. The distribution network photovoltaic storage coordinated power quality improvement system based on photovoltaic active power control according to claim 5 is characterized in that: The first control module is further used for: When the actual bus voltage value is less than the bus voltage lower limit and the photovoltaic assembly operates in a maximum power point tracking mode, the energy storage unit is controlled to discharge to control the bus voltage to a rated bus voltage.

7. The distribution network photovoltaic storage coordinated power quality improvement system based on photovoltaic active power control according to claim 5 is characterized in that: The second control module, when used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual state of charge value of the energy storage unit, the state of charge charging threshold value, the actual bus voltage value and the rated bus voltage, is specifically used to: If the actual state of charge value is less than the state of charge charging critical value, the photovoltaic component is operated in the maximum power point tracking mode and the energy storage unit is controlled to charge; if the actual state of charge value is greater than or equal to the state of charge charging critical value, the photovoltaic reference power is adjusted and the photovoltaic reference voltage is updated based on the actual bus voltage value and the rated bus voltage.

8. The distribution network photovoltaic storage coordinated power quality improvement system based on photovoltaic active power control according to claim 7 is characterized in that: The second control module, when used to adjust the photovoltaic reference power and update the photovoltaic reference voltage based on the actual bus voltage value and the rated bus voltage, is specifically used to: If the actual value of the bus voltage is less than the rated bus voltage, the photovoltaic reference power is increased and the photovoltaic reference voltage is updated; if the actual value of the bus voltage is greater than or equal to the rated bus voltage, the photovoltaic reference power is reduced and the photovoltaic reference voltage is updated.

9. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 4 when executed by a processor.

Images