PWM converter, control method and PWM converter grid-connected system

Abstract

The invention is suitable for the technical field of electric power, and provides a PWM converter, a control method and a PWM converter grid-connected system, output power adjustment values are added in the integration process of an outer ring PI controller, output power weighted distribution of PWM converters of different models and different capacities is achieved, outer ring parameters and inner ring control do not need to be modified, and the overall performance of the PWM converter is improved. Weighted distribution of the output power of the PWM converter can be achieved only by adjusting the PI control process of the PWM converter, the expandability of the system is guaranteed, and the system adapts to complex and changeable application requirements.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a PWM converter, a control method and a PWM converter grid-connected system. Background Art

[0002] PWM converter parallel operation technology has been widely used in the fields of ship integrated power system, uninterruptible power supply, multi-terminal flexible DC transmission system, micro DC grid and multi-terminal energy router because it can improve system capacity, reliability and flexibility. In parallel operation, realizing current balancing control of multiple PWM converters is one of the key technologies. Its goal is to ensure that each converter reasonably distributes output power according to its capacity and maintains stable operation. However, the existing current balancing control scheme has the following limitations in practical applications:

[0003] The current current sharing control method usually requires the careful design of the voltage outer loop and current inner loop parameters of each converter, which makes the design process complicated and requires all parallel converters to output power in a consistent control method, resulting in different types of equipment being unable to work together, poor system scalability and compatibility, and unable to meet complex and diverse application requirements. Summary of the invention

[0004] The present application provides a PWM converter, a control method and a PWM converter grid-connected system to solve the problems that when traditional PWM converters are operated in parallel, the voltage outer loop and current inner loop parameters of each converter need to be carefully designed, and the system has poor scalability and compatibility.

[0005] In a first aspect, a PWM converter is provided, comprising:

[0006] PI controller, used to control the output power based on integral control and proportional control when the PWM converter is switched to the grid;

[0007] The PI controller is also configured as:

[0008] Determine an output power regulation value of the PWM converter, the output power regulation value is obtained based on the gain of the PWM converter and a proportional coefficient of proportional control;

[0009] The output value of the integral control is adjusted by the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

[0010] In the above scheme, by adding the output power adjustment value in the integral control process of the outer loop PI control, the weighted distribution of the output power of PWM converters of different models and capacities is realized. There is no need to modify the outer loop parameters and the inner loop control. The weighted distribution of power can be achieved only by adjusting the PI control process of the PWM converter, which reduces the complexity of the design process, reduces the difficulty of debugging, and reduces the output power imbalance between PWM converters of different capacities and models, thereby ensuring the scalability and compatibility of the system, realizing the collaborative work of different types of equipment, and adapting to complex and changing application requirements.

[0011] In some embodiments, a PWM converter is provided, and a PI controller determines an output power adjustment value of the PWM converter and is configured as follows:

[0012] The gain of the PWM converter is obtained, the gain of the PWM converter is subtracted from the proportional coefficient to obtain a difference, and then the inverse of the difference is taken to obtain the output power adjustment value.

[0013] In the above scheme, the output power adjustment value is obtained by processing the gain of the PWM converter and the proportional coefficient in the PI control, which effectively balances the response speed and stability of the system. It is suitable for use in a dynamically changing system environment. By adjusting the output power adjustment value in real time, the PWM converter is guaranteed to operate stably and efficiently during grid connection and load changes.

[0014] In some embodiments, a PWM converter is provided, and a PI controller obtains a gain of the PWM converter and is configured as follows:

[0015] Obtain a gain coefficient of the PWM converter and a rated capacity of the PWM converter, and multiply the gain coefficient by the rated capacity to obtain a gain of the PWM converter;

[0016] Alternatively, the total gain of the grid-connected PWM converter and the proportion of the PWM converter in the total rated capacity of the grid-connected PWM converter are obtained, and the total gain is multiplied by the proportion to obtain the gain of the PWM converter.

[0017] In the above scheme, by allocating gains based on the proportion of rated capacity, it is possible to ensure that the power output of each converter when connected to the grid is consistent with its capacity. Through the unified total gain, the gain of each converter can be directly allocated in a proportional manner, reducing complexity and realizing weighted distribution of output power of PWM converters of different models and capacities.

[0018] In some embodiments, a PWM converter is provided, wherein a PI controller adjusts an output value of an integral control by an output power adjustment value and then feeds it back to an input end of the integral control, and is configured as follows:

[0019] Receiving a bus voltage value and a bus reference voltage value and calculating a bus voltage difference;

[0020] The output value of the integral control is multiplied by the output power adjustment value to obtain a first feedback value, and then the bus voltage difference is subtracted from the first feedback value to be used as an input value of the integral control.

[0021] In the above scheme, the first feedback value obtained by adjusting the integral output value by the output power adjustment value is further subtracted from the bus voltage difference to obtain the corrected integral input value. This process optimizes the dynamic response and stability of PI control, so that the PWM converter can more efficiently and stably adjust the weighted distribution of output power in the grid-connected system, while ensuring that the bus voltage is stable near the target value.

[0022] In some embodiments, a PWM converter is provided, wherein a PI controller determines an output power adjustment value of the PWM converter and is further configured to:

[0023] Determine an initial power value of the PWM converter, where the initial power value is obtained based on the operating state of the PWM converter;

[0024] The output value of the integral control is adjusted by the initial power value and the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

[0025] In the above scheme, by adjusting the PI controller in combination with the first and initial power values, dynamic weighted distribution of the PWM converter output power can be achieved, and PWM converters of different powers can be ensured to work together to meet load requirements and optimize the overall efficiency and stability of the system.

[0026] In some embodiments, a PWM converter is provided. When the PWM converter performs rectification, a PI controller determines an initial power value of the PWM converter and is configured as follows:

[0027] The average load rate of the PWM converter and the rated capacity of the PWM converter are obtained, and the initial power value is obtained by multiplying the average load rate by the rated capacity.

[0028] In the above scheme, by introducing the product of the average load rate and the rated capacity as the initial power value, the output power regulation of the converter under different load conditions is effectively realized. This method not only improves the stability and dynamic performance of the system, but also optimizes the operating efficiency and controller design of the converter, and is suitable for a variety of grid-connected scenarios.

[0029] In some embodiments, a PWM converter is provided. When the PWM converter is connected to an energy storage module, a PI controller determines an initial power value of the PWM converter and is configured as follows:

[0030] Obtaining the SOC reference value and SOC value of the energy storage module, and multiplying the difference between the SOC reference value and the SOC value by a preset constant to obtain an initial power value;

[0031] Alternatively, when the PWM converter is connected to an adjustable load, the PI controller determines the initial power value of the PWM converter and is configured as:

[0032] The rated power of the adjustable load or the average power within a preset time is set as the initial value of the PWM converter.

[0033] In the above scheme, by adjusting the PI control process according to the SOC difference, the output of the PWM converter can be flexibly adjusted according to the actual situation of the energy storage module to ensure that the system can work stably under different load or charging conditions.

[0034] In some embodiments, a PWM converter is provided, wherein a PI controller adjusts the output value of the integral control by an initial power value and an output power adjustment value and then feeds it back to the input end of the integral control, and is configured as follows:

[0035] Receiving a bus voltage value and a bus reference voltage value and calculating a bus voltage difference;

[0036] The output value of the integral process in PI control is subtracted from the initial power value, and then multiplied by the output power adjustment value to obtain the second feedback value, and then the bus voltage difference is subtracted from the second feedback value as the input value of the integral process.

[0037] In the above scheme, by using the rated power or average power of the load as the initial power value, the system can accurately adjust the output power of the converter to match the load demand, provide appropriate power, and avoid overload or insufficient power. Through the highly adaptable PI control, the PI controller can respond in real time when the load changes to ensure the stable operation of the system, especially for adjustable loads, PI control can adjust according to the fluctuation of load demand and reduce the response delay of the system.

[0038] In a second aspect, a control method for a PWM converter grid-connected system is provided, the method comprising the following steps:

[0039] When the PWM converter performs grid-connected switching and outputs power based on integral control and proportional control, an output power adjustment value of the PWM converter is determined, wherein the output power adjustment value is obtained based on a gain of the PWM converter and a proportional coefficient of proportional control;

[0040] The output value of the integral control is adjusted by the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

[0041] In a third aspect, a PWM converter grid-connected system is provided, comprising the above-mentioned PWM converter.

[0042] In a fourth aspect, an electronic device is provided, comprising a device for executing the control method of the PWM converter grid-connected system in the second aspect.

[0043] In a fifth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and when the computer program is displayed to a PI controller to run, the PI controller executes the control method of the PWM converter grid-connected system in the second aspect.

[0044] In a sixth aspect, a computer program product is provided, the computer program product comprising: a computer program, when the computer program is executed by an electronic device, the PI controller executes the control method of the PWM converter grid-connected system in the second aspect.

[0045] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0047] Figure 1 It is a structural schematic diagram of a PWM converter grid-connected system in the prior art;

[0048] Figure 2 It is a control block diagram of a PI controller in the prior art;

[0049] Figure 3 is an integral control block diagram of a PI controller in one embodiment of the present invention;

[0050] Figure 4 is an open loop curve diagram of a PI controller in one embodiment of the present invention;

[0051] Figure 5 is a flow chart of a control method of a PWM converter grid-connected system in one embodiment of the present invention;

[0052] Figure 6 yes Figure 5 A schematic diagram of an implementation process of step S20;

[0053] Figure 7is a control block diagram of a PI controller in one embodiment of the present invention;

[0054] Figure 8 is another integral control block diagram of a PI controller in one embodiment of the present invention;

[0055] Fig. 9 is another open-loop curve diagram of a PI controller in one embodiment of the present invention;

[0056] Fig.10 is another open-loop curve diagram of a PI controller in one embodiment of the present invention;

[0057] Fig.11 is another flow chart of a control method of a PWM converter grid-connected system according to an embodiment of the present invention;

[0058] Fig.12 It is a structural schematic diagram of a PWM converter grid-connected system in one embodiment of the present invention;

[0059] Fig.13 is another structural schematic diagram of a PWM converter grid-connected system in one embodiment of the present invention;

[0060] Fig.14 yes Fig.11 A schematic diagram of an implementation process of step S21;

[0061] Fig.15 is another integral control block diagram of a PI controller in one embodiment of the present invention;

[0062] Fig.16 It is the bus voltage and output power curve diagram when two PWM converter units are started simultaneously;

[0063] Fig.17 It is a curve diagram of bus voltage and output power when another PWM converter unit is switched in during the startup of one PWM converter unit;

[0064] Fig.18 It is a curve diagram of bus voltage and output power when one PWM converter unit is in steady state and another PWM converter unit is switched in;

[0065] Fig.19 It is a curve diagram of bus voltage and output power cut out by another PWM converter unit when one PWM converter unit is in steady state;

[0066] Fig. 20 It is a bus voltage and output power curve diagram of another PWM converter unit changing the initial power value when one PWM converter unit is in a steady state;

[0067] Fig.21It is a schematic diagram of the structure of an electronic device in one embodiment of the present invention. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] It should be understood that when used in the present specification and the appended claims, unless otherwise specified, the term " / " means or, for example, A / B can mean A or B; "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0070] In the description of the present specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or their collections. It should also be understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0071] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0072] References to "one embodiment" or "some embodiments" etc. described in the present specification mean that one or more embodiments of the present invention include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0073] It should be understood that the order of execution of the steps in the following embodiments does not imply a precedence of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0074] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0075] It is important to understand that Figure 1 As shown in the figure, when the PWM converter is connected to the grid, the PWM converter is controlled by the PI controller for outer loop PI control and inner loop control. Figure 2 As shown, the PI controller consists of two parts: proportional control and integral control. The proportional control is based on the size of the deviation according to the proportional coefficient K p The control signal is output proportionally, and the integral controller I responds quickly to the deviation. The integral term gradually increases with the accumulation of time, eliminating the stability error. In terms of the DC parallel output power technology of PWM converters, the existing technologies all focus on the output balancing strategy of PWM converters of the same specification. The present invention breaks through the limitations of traditional thinking by taking a different approach and proposes a new technology of adding an output power adjustment value to the integrator in the PI controller, which can support the weighted output of the output power of PWM converters of different models. Figure 2 The integrator I in the PI controller is modified by adding the output power adjustment value D to the integrator I and adding the structure of the integrator. Figure 3 As shown in Figure 1, it is an integrator design to increase the output power adjustment value D. Figure 4 As shown, the integrator with the added output power adjustment value D is tested. When the output power adjustment value D1 is 0.005, the open-loop gain is 200; when the output power adjustment value D2 is 0.0067, the open-loop gain is 1500; when the output power adjustment value D3 is 0.01, the open-loop gain is 100. It can be seen that the output power adjustment value D is a constant far less than 1, and the output power adjustment value D has a very slow effect on the integral value of the integrator. Therefore, the integrator after adding the output power adjustment value D can still maintain a very high gain for the DC component. On the basis of not affecting the dynamic response of the integrator, the gain of the integrator for DC is changed, thereby changing the output power of the PWM converter. This technical solution does not need to modify the outer loop parameters and the inner loop control. It only needs to add the output power adjustment value to the outer loop PI control integrator to realize the weighted distribution of the DC side parallel output power of PWM converters of different models and capacities.

[0076] In order to facilitate further understanding of the technical solutions in some embodiments of the present application, the technical solutions of the PWM converter, the control method and the PWM converter grid-connected system, and how the technical solutions solve the above-mentioned technical problems are described in detail below in combination with some specific embodiments and drawings. The various embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of them.

[0077] The control method of the PWM converter provided by the embodiment of the present invention can be applied in the following aspects: Figure 1 In the PWM converter grid-connected system shown, the PWM converter grid-connected system includes multiple PWM converters. Each converter uses a PI controller to adjust its output power. A PWM (pulse width modulation) converter is an electronic device used to change voltage, current or power, and controls the output by adjusting the pulse width. PWM converters are usually used to convert input voltage into the required output voltage or current, and have good regulation characteristics. PI proportional integral control is a common control algorithm that uses the proportional coefficient Kp and the integral coefficient Ki to control the output. By adjusting the output signal, the steady-state error of the system is reduced and the response speed is improved. The PI controller is often used to adjust the output power of the PWM converter to keep it at a predetermined target value. The PI controller refers to an intelligent control unit in the entire system, which is responsible for adjusting the work of the PWM converter, and ensures the performance optimization of the converter when it is connected to the grid by monitoring the output of the PWM converter in real time and adjusting the control parameters.

[0078] In some embodiments, Figure 5 As shown, a control method for a PWM converter is provided, and the method is applied in Figure 1 Taking the PI controller of the PWM converter as an example, the PI controller is configured to perform the following steps:

[0079] Step S10: determining an output power adjustment value of the PWM converter, where the output power adjustment value is obtained based on the gain of the PWM converter and a proportional coefficient of proportional control.

[0080] Among them, the PWM converter refers to the converter that needs to be connected to the power grid in the grid-connected system. Each PWM converter needs to adjust its output power according to its own working state and input voltage to ensure that it can be smoothly connected to the grid and work in coordination with other converters. Grid connection refers to connecting the output current of the PWM converter with the current of the power grid. The grid-connected switching of the PWM converter includes but is not limited to starting one or more PWM converters at the same time, switching in or out of other PWM converters during the PWM converter startup process, and switching in or out of other PWM converters during the PWM converter working process. When the PWM converter is connected to the grid, PI control is usually used to maintain the stability and precise adjustment of the output power. The introduction of the output power adjustment value refers to the introduction of a new adjustment factor on the basis of the existing PI control, which is used to finely adjust the control process of the output power. The introduction of this new adjustment value can fine-tune the original PI control process based on the current state of the PWM converter, so that the output of the converter can more accurately match the target output power. By introducing this new adjustment factor, the control system can dynamically adjust the response characteristics of the PI control, for example, by calculating the gain change of the PWM converter in real time, adjusting the PI control process, and optimizing the output power of the PWM converter.

[0081] Among them, when multiple PWM converters are connected to the grid, all PWM converters need to work in coordination to ensure the stability and power output of the grid. Since the working state and input conditions of each PWM converter may be different, relying solely on fixed PI control cannot fully meet the optimal performance requirements of the system. The introduction of the output power adjustment value allows each converter to make appropriate adjustments based on its current working state, thereby optimizing the working efficiency and power output of the entire grid-connected system.

[0082] Among them, in PI control, the gain of the PWM converter is usually set according to its design or performance characteristics. Through the gain of the PWM converter, the PI controller can calculate the appropriate PI control adjustment value, and the output power adjustment value is obtained based on the gain of the PWM converter and the proportional coefficient of the proportional control according to the preset relationship.

[0083] Step S20: the output value of the integral control is adjusted by the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

[0084] Among them, according to the calculated output power adjustment value, the PI controller adjusts the integral control process of the PWM converter. When multiple parallel PWM converters work at the same time, their respective power outputs will be weighted according to certain weights to achieve global power balance. When multiple PWM converters are connected to the grid, the output power of each converter will have certain fluctuations or inconsistencies. Therefore, by balancing the output of each converter through weighted allocation, a stable and overall system power output is obtained, which helps to reduce the load differences between each converter and ensure the overall stability and reliability of the system.

[0085] Among them, multiple PWM converters work together when connected to the grid, and there are multiple working states, such as the converter switching on and off, and the gain of the PWM converter accounts for the total gain of all PWM converters is also changing. The PI controller calculates the PI control adjustment value according to the gain of each converter, and uses these adjustment values ​​to optimize the overall output power of the system, ensuring the balance and stability of the output power, and finally realizing efficient grid-connected operation of the system.

[0086] In order to achieve the purpose of weighted distribution of output power, the embodiment of the present invention proposes to add an output power adjustment value to the PI control. After adding the output power adjustment value, the response of the PI control becomes more stable and controllable, thereby achieving more accurate weighted output regulation. As an example, assume that there are two PWM converters in the system: PWM converter A and PWM converter B. Assume that the rated power of PWM converter A is 120kW, and the rated power of PWM converter B is 80kW. In order to achieve reasonable power distribution, the gain of the PWM converter is proportional to the rated capacity, and the gain of PWM converter A is set to 12 and the gain of PWM converter B is set to 8. The output power adjustment value of PWM converter A is calculated according to the gain and proportional coefficient of PWM converter A, and the output power adjustment value of PWM converter B is calculated according to the gain and proportional coefficient of PWM converter B. By increasing the output power adjustment value to achieve weighted output adjustment of the actual output power of each converter, converter A will output a larger proportion of power (for example, 60%), and converter B will output less power (for example, 40%).

[0087] The PWM converter provided in this embodiment does not require complex and sophisticated design of the voltage outer loop and current inner loop of each converter. Instead, the output power of the PWM converter is adjusted by adding an output power adjustment value to the outer loop PI control integrator, thereby reducing the complexity of the design process and the difficulty of debugging. Weighted power distribution can be achieved only by adjusting the PI control process of the PWM converter, reducing the output power imbalance between PWM converters of different capacities and models, ensuring the scalability and compatibility of the system, achieving collaborative work of different types of equipment, and adapting to complex and changing application requirements.

[0088] As an implementation method for calculating the output power adjustment value, in step S10, the PI controller obtains the output power adjustment value of the PWM converter and is configured as follows:

[0089] The gain of the PWM converter is obtained, the gain of the PWM converter is subtracted from the proportional coefficient to obtain a difference, and then the inverse of the difference is taken to obtain the output power adjustment value.

[0090] Among them, the gain of the PWM converter and the proportional coefficient in the PI control are obtained, and the output power adjustment value is calculated according to the following formula:

[0091]

[0092] Where D is the output power adjustment value, k r is the gain of the PWM converter, k p is the proportionality coefficient.

[0093] Among them, in PI control, the proportional coefficient K p Determines the strength of the system response. A larger proportional coefficient will make the system respond more quickly to errors, but it may also lead to over-adjustment and even cause system oscillation; a smaller K p This may lead to a slow response. According to the formula, the output power regulation value is calculated by the reciprocal of the difference between the gain of the PWM converter and the proportional coefficient in the PI control. The larger the difference between the gain and the proportional coefficient, the greater the deviation between the converter's response and the controller's expected behavior. If the gain and the proportional coefficient are close, it means that the controller has been able to match the converter's characteristics well. The purpose of taking the reciprocal is to reverse the effect of the difference, so that when the difference is larger, the output power regulation value is smaller; when the difference is smaller, the output power regulation value is larger. This design can effectively balance the stability and response speed of the control system. According to the difference between the gain and the proportional coefficient, the regulation strength of the PI controller is dynamically adjusted. When the difference is small, the output power regulation value is large, which means that the controller responds more quickly to the error adjustment; when the difference is large, the regulation value is small to avoid overreaction or oscillation of the system.

[0094] As an example, assume that the gain of PWM converter A is 1.5 and the proportional coefficient is 1.2. The gain of PWM converter B is 1.0 and the proportional coefficient is 1.5. According to the formula, the output power adjustment value of PWM converter A is 3.33, and the output power adjustment value of PWM converter B is 2. The difference between the gain and the proportional coefficient of converter A is small (0.3), indicating that its dynamic performance matches the design of the controller well, the output power adjustment value is large (3.33), and the PI controller can adjust the output more quickly. The difference between the gain and the proportional coefficient of converter B is large (0.5), indicating that there is a certain deviation between its dynamic performance and the design of the controller, and the output power adjustment value is small (2.0). The PI controller will adjust the output more smoothly to avoid oscillation.

[0095] The technical effect of this implementation is that the output power adjustment value is obtained by processing the gain of the PWM converter and the proportional coefficient in the PI control, which effectively balances the response speed and stability of the system. It is suitable for use in a dynamically changing system environment. By adjusting the output power adjustment value in real time, it is ensured that the PWM converter operates stably and efficiently during grid connection and load changes.

[0096] As a first implementation method for obtaining the gain of the PWM converter, a PI controller obtains the gain of the PWM converter and is configured as follows:

[0097] The gain coefficient of the PWM converter and the rated capacity of the PWM converter are obtained, and the gain of the PWM converter is obtained by multiplying the gain coefficient by the rated capacity.

[0098] The gain coefficient of the PWM converter and the rated capacity of the PWM converter are obtained, and the gain of the PWM converter is calculated according to the following formula:

[0099] k r =g r ×P n ;

[0100] Among them, k r is the gain of the PWM converter, g r is the gain factor of the PWM converter, P n is the rated capacity of the PWM converter.

[0101] Among them, the gain of the PWM converter directly affects the regulation of the output power and the stability of the system. The gain coefficient is usually a constant related to the characteristics of the PWM converter, reflecting the response characteristics of the converter under specific working conditions. It is usually determined when the converter is designed, or adjusted according to the actual operating conditions. The rated capacity refers to the maximum output power of the PWM converter under standard working conditions, which is usually determined by the design parameters and manufacturing standards of the converter. It is a key indicator for evaluating the performance of the converter. For example, the rated capacity of a converter may be 5kW, which means that the converter can provide a maximum output power of 5kW under normal working conditions. The gain coefficient is the ratio of the gain of the PWM converter to the total rated capacity. This method ensures that the gain of each converter in the system matches its output power capability. The obtained gain coefficient g r And rated capacity P n Multiply them together to get the gain k of the PWM converter. r .

[0102] The technical effect of this implementation is that it optimizes the power regulation and coordination of multiple PWM converters when connected to the grid, ensuring stable operation of the system. For multi-converter grid-connected systems, especially when the PWM converter is switched in or out for grid connection, it can play a key role and ensure the efficiency and stability of the system.

[0103] As a second implementation method for obtaining the gain of the PWM converter, the PI controller obtains the gain of the PWM converter and is configured as follows:

[0104] The total gain of the grid-connected PWM converter and the proportion of the PWM converter in the total rated capacity of the grid-connected PWM converter are obtained, and the gain of the PWM converter is obtained by multiplying the total gain by the proportion.

[0105] The total gain of all PWM converters and the rated capacity of the PWM converter are obtained, and the gain of the PWM converter is calculated according to the following formula:

[0106]

[0107] Among them, k r is the total gain of all grid-connected converters, P n is the rated capacity of the converter.

[0108] Among them, the total gain refers to the sum of the gains of all grid-connected converters. The size of the total gain affects the power output of the entire system and reflects the synergistic effect of multiple converters when they are connected to the grid. The total gain is a summary indicator that describes the overall response capability of the grid-connected system. The rated capacity is the maximum output power of the PWM converter under standard operating conditions. The gain of the PWM converter is the total gain (ktotal gain) multiplied by the ratio of the rated capacity of the PWM converter to the total capacity of all grid-connected converters. The gain of the PWM converter is proportionally distributed by the total gain, and the proportional factor is the ratio of the rated capacity of the PWM converter to the total rated capacity. This method ensures that the gain of each converter in the system matches its output power capability.

[0109] The technical effect of this embodiment is that by allocating gains based on the proportion of rated capacity, it is possible to ensure that the power output of each converter when connected to the grid is consistent with its capacity. Through a unified total gain, the gain of each converter can be directly allocated in proportion, reducing complexity and achieving weighted distribution of output power of PWM converters of different models and capacities.

[0110] In some embodiments, Figure 6 As shown, in step S20, the PI controller adjusts the output value of the integral control by the output power adjustment value and then feeds it back to the input end of the integral control, and is configured as follows:

[0111] Step S201: Receive a bus voltage value and a bus reference voltage value and calculate a bus voltage difference.

[0112] Among them, the bus voltage value is the real-time voltage in the converter system, usually referring to the voltage of the DC bus or AC bus. The bus reference voltage value is the desired bus voltage, which is usually set by external control or system and used as the target voltage value. The bus voltage difference is the difference between the actual bus voltage and the desired voltage, reflecting the deviation of the current bus voltage, and is the key input used to adjust the control behavior in PI control. The PI controller first receives the real-time bus voltage value and the reference voltage value. Then, by calculating the difference between the two, the bus voltage difference is obtained. This difference represents the error of the bus voltage, and the controller needs to adjust the output power of the converter based on this error.

[0113] Step S202: multiply the output value of the integral control by the output power adjustment value to obtain a first feedback value, and then subtract the bus voltage difference from the first feedback value to obtain an input value for the integral control.

[0114] The integral part of the PI controller accumulates the bus voltage difference and uses the accumulated result as output. Figure 7 As shown, the output value I of the integration process is obtained OUT, the output value represents the current system regulation demand calculated based on the voltage error accumulation, which is used to drive the power adjustment of the converter. OUT The first feedback value D×I is obtained by adjusting the output power adjustment value D OUT , subtract the bus voltage difference from the first feedback value to obtain e(t)-D×I OUT , the output I(t) during the integration process is:

[0115] I(t)=∫(e(t)-D×I OUT )dt.

[0116] When the load changes or the bus voltage fluctuates, the output power adjustment value will respond through the integrator to ensure that each converter dynamically adjusts its output power. The output power adjustment value feedback limits the power adjustment range, making the power distribution more stable and avoiding over-adjustment or oscillation. The output power adjustment value is calculated based on the gain of the converter and is used as a proportional factor to adjust the size of the integral output. When the output power adjustment value is large, the impact of the integral output value is amplified, making the system more sensitive to error changes. When the output power adjustment value is small, the impact of the integral output value is weakened, thereby improving the stability of the system and preventing over-adjustment or oscillation. The first feedback value is the integral output adjusted by the output power adjustment value, which is used to reflect the adjusted error compensation. The bus voltage difference is the input signal of the controller, reflecting the deviation between the current voltage and the target voltage. The PI controller needs to adjust the output power according to the voltage difference to keep the bus voltage stable. Subtracting the bus voltage difference from the first feedback value can further correct the error. As a dynamic compensation term, the first feedback value can smooth the error signal and avoid system oscillation or overshoot caused by directly using the bus voltage difference. After the subtraction operation, the result is used as the input value of the integration process and reflects the corrected error.

[0117] The technical effect of this embodiment is that the first feedback value obtained by adjusting the integral output value by the output power adjustment value is further subtracted from the bus voltage difference to obtain the corrected integral input value. This process optimizes the dynamic response and stability of PI control, so that the PWM converter can more efficiently and stably adjust the weighted distribution of output power in the grid-connected system, while ensuring that the bus voltage is stable near the target value.

[0118] In addition to supporting the weighted output of the PWM converter by outputting a power adjustment value, the embodiment of the present invention also fully considers the impact of different initial states on the parallel PWM converters. In the prior art, the initial state of the PI integrator is usually set to 0, so the energy flow of the parallel PWM converters is consistent. After the initial state of the PI integrator is designed in the embodiment of the present invention, the steady state of each PWM converter is adjusted in the same direction based on the initial state, which can support working conditions with inconsistent energy flows. The initial state of the PI integrator added by the present invention does not set the initial value of the integral item. The initial value of the integral item is still 0. Figure 8 As shown, in Figure 2 The damping feedback link adds an initial power value P0, so that the initial value can be set arbitrarily without considering power balance. Fig. 9 As shown in the figure, when the deviation input is 0, the initial value I1 is 80, the initial value I2 is 50, and the initial value I3 is -20. Fig.10 As shown in the figure, when the deviation input is not 0, the integrator will gradually reach a new balance, that is, the integrator will slowly and smoothly change from the current state to the initial power value P0. Changing the initial power value P0 in any case will not cause system disturbance. Therefore, in practical applications, the initial state can be modified in real time according to actual needs.

[0119] In some embodiments, Fig.11 As shown, the PI controller determines the output power regulation value of the PWM converter and is also configured as:

[0120] Step S11: Determine an initial power value of the PWM converter, where the initial power value is obtained based on the operating state of the PWM converter.

[0121] The operating state refers to the current operating state or condition of the PWM converter, such as load changes, bus voltage fluctuations, system operating temperature, etc. The initial power value is dynamically adjusted according to the real-time operating state of the converter. The PI controller monitors the operating state of the PWM converter in real time. These monitoring states may include changes in load, changes in bus voltage, and possible temperature changes. According to the operating state, the control dynamically adjusts the parameters of the PI controller. For example, when the load increases, the proportional gain or integral gain may need to be adjusted to ensure the stability of the converter output power. The dynamic adjustment of the initial power value enables the system to adapt to different working conditions and ensure that the high-efficiency PWM converter can still operate under various working environments. This adjustment can avoid the performance degradation of the controller due to changes in working conditions and maintain the stability of the system output power.

[0122] Step S21. Feedback the output value of the integral control to the input end of the integral control through the initial power value and the output power adjustment value to adjust the output power of the PWM converter.

[0123] Among them, in the grid-connected control, the PI control process of the PWM converter is adjusted based on the output power adjustment value and the initial power value, so as to realize the weighted distribution of the output power of the PWM converter when it is connected to the grid. This method can dynamically adapt to the working state of the system, optimize the power output, and enhance the stability and synergy of the system. The output power adjustment value is mainly related to the static characteristics of the PWM converter (such as gain and capacity), and is used to match the basic adjustment of the PI controller. The initial power value is dynamically calculated based on the real-time working state of the PWM converter (such as load rate, voltage deviation, SOC, etc.), and is used to adjust the responsiveness and stability of the PI controller, providing adaptability to dynamic working conditions. The initial power value allows the user to flexibly set the output power difference of each grid-connected unit in the system. The adjustment of the power difference will not destroy the overall stability of the parallel system, because the design of the controller can dynamically adapt to these adjustments, and dynamically adjust the proportional and integral control according to the load, input voltage, energy storage state, etc., making the system more flexible. The output power adjustment value and the initial power value are used to adjust the PI controller to realize the weighted distribution of the output power of the PWM converter. The output power is dynamically adjusted according to the converter's gain, capacity and operating status to ensure that multiple converters work together.

[0124] The technical effect of this embodiment is that by adjusting the PI controller in combination with the output power adjustment value and the initial power value, dynamic weighted distribution of the output power of the PWM converter can be achieved, and PWM converters of different powers can be ensured to work together to meet load requirements and optimize the overall efficiency and stability of the system.

[0125] As an implementation method for obtaining the initial power value, when the PWM converter performs rectification, the PI controller determines the initial power value of the PWM converter and is configured as follows:

[0126] The average load rate of the PWM converter and the rated capacity of the PWM converter are obtained, and the initial power value is obtained by multiplying the average load rate by the rated capacity.

[0127] The average load rate of the PWM converter and the rated capacity of the PWM converter are obtained, and the initial power value of the PWM converter is calculated according to the following formula:

[0128] P0=β×P n ;

[0129] Among them, P0 is the initial power value, β is the average load rate of the PWM converter, P n is the rated capacity of the PWM converter.

[0130] The average load rate refers to the average load value of the PWM converter over a period of time, usually expressed as the ratio of the converter output power to its rated power. For example, if the rated capacity of the converter is 10kW, and its output power is 5kW during a specific period of time, its load rate is 50%. The rated capacity is the maximum output power specified when the PWM converter is designed, indicating the maximum load capacity at which the converter can work stably. For example, the rated capacity of a converter is 10kW. By dividing the average load rate β of the converter by the rated capacity P n Multiply them together to get the initial power value P0. This value reflects the adjustment requirements of the PWM converter under the current load conditions. If the load rate is high, P0 will also be larger, which means that the PI controller needs to make a stronger response to maintain the stability of the output power.

[0131] As an example, Fig.12 As shown, the first rectifier 10, the second rectifier 20, and the third rectifier 30 are connected in parallel to provide output power for the load 40. The first rectifier 10 and the second rectifier 20 are the same device, and the capacity of the first rectifier 10 and the second rectifier 20 are both P n , the capacity of the third rectifier 30 is 2P n , the first rectifier 10 and the second rectifier 20 are in exactly the same working state and can set the same initial power value as P1, and the initial power value of the third rectifier is P2. If the units of the parallel system only have different capacities and the working conditions are exactly the same, the initial power value P1 = P2. If the system is considered to run for a long time, the average load rate of the rectifier is β (0≤β≤100%), then the initial power value is set:

[0132] P1=β×P n ;

[0133] P2=β×(2P n ).

[0134] The technical effect of this implementation is that by introducing the product of the average load rate and the rated capacity as the initial power value, the output power regulation of the converter under different load conditions is effectively realized. This method not only improves the stability and dynamic performance of the system, but also optimizes the operating efficiency and controller design of the converter, and is suitable for a variety of grid-connected scenarios.

[0135] As a second implementation method for obtaining the initial power value, when the PWM converter is connected to the energy storage module, the PI controller determines the initial power value of the PWM converter and is configured as follows:

[0136] The SOC reference value and SOC value of the energy storage module are obtained, and the initial power value is obtained by multiplying the difference between the SOC reference value and the SOC value by a preset constant.

[0137] The SOC reference value and SOC value of the energy storage module are obtained, and the initial power value of the PWM converter is calculated according to the following formula:

[0138] P0=k(SOC ref -SOC);

[0139] Among them, P0 is the initial power value, k is a constant, SOC ref is the SOC reference value.

[0140] SOC refers to the current state of charge of the energy storage module (such as a battery), usually expressed as a percentage of the state of charge (0% to 100%). The higher the SOC value, the more the energy storage module is charged, and the lower the SOC value, the less the energy storage module is charged. ref ) is a preset target value, usually set according to system requirements or design goals. For example, SOC ref It may be the target charging level of the energy storage module. The system will decide whether to charge or discharge based on this reference value. The initial power value is calculated by the formula, and the initial power value is used to adjust the control parameters of the PWM converter. The constant k is used to adjust the influence of the SOC difference on the control adjustment value. This constant affects the sensitivity of the control. A larger constant k will make the response to SOC changes faster. The PI controller obtains the SOC reference value SOC ref and the current SOC value, and then calculate the initial power value P0 according to the above formula. The initial power value P0 reflects the difference between the current charging state of the energy storage module and the target state, which in turn affects the output regulation of the PWM converter.

[0141] The technical effect of this embodiment is that by adjusting the PI control process according to the SOC difference, the output of the PWM converter can be flexibly adjusted according to the actual situation of the energy storage module to ensure that the system can work stably under different load or charging conditions.

[0142] As an implementation, when the PWM converter is connected to an adjustable load, the PI controller determines an initial power value of the PWM converter and is configured as:

[0143] The rated power of the adjustable load or the average power within a preset time is set as the initial power value of the PWM converter.

[0144] Among them, when the PWM converter is connected to an adjustable load, the PI controller optimizes the output of the converter by adjusting the initial power value to ensure that the output power matches the load demand. An adjustable load refers to a load device that can adjust the power demand according to a control signal. For example, some load devices in industrial applications or power systems can adjust the power they consume according to the operating conditions of the power system. The rated power of the load device refers to the maximum allowable power value of the device under standard working conditions. The average power within a set time refers to the average power consumed by the load device within a set time interval. If the load is not constant, this value is usually obtained by measuring the power consumption of the load within a certain time and calculating its average value. In this embodiment, the PI controller sets the initial power value according to the rated power of the connected adjustable load or the average power within a preset time. This adjustment value will directly affect the output power of the PWM converter. If the rated power is used, the PI controller obtains the rated power of the adjustable load and sets it as the initial power value of the PWM converter. If the average power is used, the PI controller calculates the average power of the load within a preset time and sets it as the initial power value of the PWM converter. The PI controller needs to obtain the rated power of the adjustable load or the average power within a preset time, which can be done by monitoring the load state or through the control interface of the load. Once the power information of the load is obtained, the PI controller will use this information to set the initial power value of the PWM converter. This value will be used in the calculation of the PI controller to adjust the output power of the converter. The PI controller will adjust the output of the PWM converter according to the set initial power value to ensure that the output power meets the load requirements. The output power of the PWM converter will be consistent with the rated power or average power of the load, so that the system can work efficiently and stably.

[0145] The technical effect of this embodiment is that by using the rated power or average power of the load as the initial power value, the system can accurately adjust the output power of the converter to match the load demand, and can provide appropriate power to avoid overload or insufficient power. Through the highly adaptable PI control, the PI controller can respond in real time when the load changes to ensure the stable operation of the system, especially for adjustable loads, PI control can be adjusted according to the fluctuation of load demand to reduce the response delay of the system.

[0146] As an example, Fig.13 As shown, the DCDC module Dev1 is connected to the energy storage battery E1, the DCDC module Dev2 is connected to the battery E2, the DCDC module Dev3 is connected to the photovoltaic device E3, the DCAC module Dev4 is connected to the adjustable load R1, and the DCAC module Dev5 is connected to the fixed load R2.

[0147] DCDC module Dev1 and DCDC module Dev2 are connected to energy storage batteries respectively, which need to store excess energy when photovoltaic power is in excess and provide energy to the load when photovoltaic power is insufficient. Therefore, the energy storage battery has an ideal SOC state (such as SOC50%), and the initial power value can be set according to the dynamic deviation of SOC:

[0148] P0=k(SOC ref -SOC);

[0149] Among them, P0 is the initial power value, k is a constant, SOC ref is the SOC reference value.

[0150] The energy storage battery adjusts the charge and discharge power according to the dynamic deviation of SOC (state of charge). When the battery SOC is lower than the ideal value, the initial power value guides the battery to charge and absorb excess photovoltaic energy. When the battery SOC is higher than the ideal value, the initial power value guides the battery to discharge, supply energy to the load, and prevent the bus voltage from dropping. By dynamically adjusting the initial power value, the energy storage battery can maintain fast response and stable operation under different operating conditions.

[0151] The DCDC module Dev3 is connected to the photovoltaic device E3, and the initial power value is 0.

[0152] The DCAC module Dev4 is connected to the adjustable load R1. In order to work in a stable bus state, the rated power of the adjustable load or the average power over a period of time can be set as the initial value. The power consumption is dynamically adjusted according to the fluctuation of the bus voltage, thereby stabilizing the DC bus state and preventing the bus voltage from being too high or too low due to photovoltaic power generation or load changes. If there is a lack of historical data, the rated power of the adjustable load can be used as the initial value. The rated power can quickly put the DCAC module Dev4 into operation and respond to bus fluctuations. If there is operating data, the initial value can be set according to the average power over a period of time. The average power can more accurately reflect the current operating conditions and reduce the system regulation amplitude. When the bus voltage fluctuates, Dev4 adjusts its power consumption to absorb or reduce the load to stabilize the bus voltage: when the bus voltage is higher than the reference value, the load power consumption is increased to reduce the voltage. When the bus voltage is lower than the reference value, the load power consumption is reduced to increase the voltage.

[0153] The DCAC module Dev5 is connected to a fixed load R2, and the initial power value is 0.

[0154] As an implementation method, Fig.14 and Fig.15 As shown, the PI controller adjusts the PI control process of the PWM converter according to the output power adjustment value and the initial power value, and is configured as:

[0155] Step S13: Receive the bus voltage value and the bus reference voltage value and calculate the bus voltage difference.

[0156] Among them, the bus voltage value refers to the bus voltage in the power system where the PWM converter is located, that is, the voltage between the PWM converter and the power grid. The bus voltage usually fluctuates with changes in the load. The bus reference voltage value is the set expected voltage value, which is usually based on the requirements or standards of the system and represents the voltage of the system under ideal conditions. It is obtained by calculating the difference between the bus voltage value and the bus reference voltage value. This difference represents the deviation between the actual voltage and the expected voltage, and is usually used as the input of the PI controller for adjustment.

[0157] Step S23. Subtract the output value of the integral process in the PI control from the initial power value, multiply it by the output power adjustment value to obtain a second feedback value, and then subtract the bus voltage difference from the second feedback value to use as the input value of the integral process.

[0158] The integral part of the PI controller accumulates the bus voltage difference and uses the accumulated result as output. OUT , the output value represents the current system regulation demand calculated based on the voltage error accumulation, which is used to drive the power adjustment of the converter. OUT Subtract the initial power value P0 to get I OUT -P0, the first feedback value D×(I OUT -P0), subtract the bus voltage difference from the first feedback value to obtain e(t)-D×I OUT , the output I(t) during the integration process is:

[0159] I(t)=∫(e(t)-D×(I OUT -P0)dt.

[0160] Among them, the integral part of the PI controller calculates the cumulative error to reflect the long-term deviation trend of the system. The initial power value is a regulation value that is dynamically adjusted according to the operating status of the target device, indicating the current additional output power of the device. The integral output value is subtracted from the initial power value to remove the additional output power from the total output power, and the second feedback value is obtained by adjusting the initial power value again. The subtraction result is corrected twice to further adapt to the current working status of the device. The result of the second feedback value adjustment is used as a dynamic compensation signal for the bus voltage difference. The feedback value can be dynamically adjusted according to the load rate of the equipment or the energy storage status. The bus voltage difference is subtracted from the second feedback value to generate a comprehensive corrected error signal, which is used as the input value of the integration process to update the cumulative error of the system.

[0161] The following is a detailed description of the embodiments of the present invention through a specific experimental process:

[0162] Step 1: Set the voltage outer loop PI control of the control part of the PWM converter of the parallel system to Figure 7 The structure shown in the figure adds an output power adjustment value.

[0163] Step 2: Design the gain coefficient of unit capacity input deviation, obtain the gain of a single device by multiplying the gain coefficient by the device capacity, and then calculate the output power adjustment value.

[0164] Alternatively, the total gain of the parallel system can be designed first, and then the gain coefficient of each unit can be calculated according to the capacity proportion of each unit, and then the output power adjustment value can be calculated.

[0165] Step 3: The device startup supports black start, and any PWM converter or multiple PWM converters can start up simultaneously to establish the bus. Fig.16 As shown, set device 1 and device 2 to output power at the same time. Assuming that the power required by the load is 160KW, set the total gain of device 1 and device 2 so that the power output by device 1 and device 2 is 160KW. Calculate the gains of device 1 and device 2 according to the capacity ratio of device 1 and device 2 respectively. Calculate the output power adjustment value of device 1 and device 2 according to the gain and proportional coefficient of device 1 and device 2. At the same time, start device 1 and device 2. Device 1 and device 2 adjust the integration process according to their respective output power adjustment values. The bus voltage gradually balances to 800V. The output power of device 1 gradually balances to 70KW from the start. The output power of device 2 gradually balances to 90KW from the start. At the same time, it is also possible to put new equipment into the startup process during the startup process, such as Fig.17 As shown, device 1 is started at time 0, and device 2 is started at 0.05 seconds. The bus voltage gradually balances to 800V, the output power of device 1 gradually balances to 70KW from the start, and the output power of device 2 gradually balances to 90KW from the start.

[0166] Step 4: Switching in and out of the device. The switching in and out of the device is not subject to any restrictions. The PWM converter of the present invention can be switched in and out at any time, and the system will automatically and smoothly enter a new balance. Fig.18As shown, device two is started at time 0. At this time, device two needs to output power alone, and the power required by the load is 160KW. The gain of device two is set according to the power required by the load, and the output power adjustment value of device two is calculated according to the gain of device two. The integral process of the PI controller is adjusted according to the output power adjustment value of device two so that device two outputs 160KW, and the bus voltage is 800V. Device one is started after 0.3 seconds, and the gains of device one and device two are calculated according to the capacity ratio of device one and device two, respectively. The output power adjustment value of device one and device two are calculated according to the gain and proportional coefficient of device one and device two. When device one is connected, device one and device two adjust the integral process according to their respective output power adjustment values, and the output power of device two gradually balances to 90KW, and the output power of device one gradually balances to 70KW. As shown Fig.19 As shown in the figure, device 1 and device 2 are put into operation at the same time. The output power adjustment value of device 1 and device 2 are calculated according to the gain and proportional coefficient of device 1 and device 2. The stable output power of device 1 is 90KW, the stable output power of device 2 is 60KW, and the bus voltage is 800V. After 0.5 seconds, device 1 is cut out, and the output power of device 1 becomes 0. Device 2 needs to output power alone, and the power required by the load is 160KW. The gain of device 2 is set according to the power required by the load, and the output power adjustment value of device 2 is calculated according to the gain of device 2. According to the output power adjustment value of device 2, the integral process of the PI controller is adjusted to make device 2 output 160KW. After PI adjustment, the output power of device 1 is gradually balanced to 160KW.

[0167] Step 5: Before starting or during operation, change the initial value of the outer loop in real time according to the actual situation, and the system will automatically and smoothly enter a new balance. Fig. 20 As shown, the load requires 160KW of power. The gains of device 1 and device 2 are calculated according to the capacity ratio of device 1 and device 2, and the output power adjustment value of device 1 and device 2 are calculated according to the gains and proportional coefficients of device 1 and device 2. The steady-state output power of device 1 is 68KW, and the steady-state output power of device 2 is 92KW. Device 1 increases the initial power value of 30KW at 0.4 seconds. The power required by the load 160KW minus the initial power value of 30KW equals 130KW. The gains of device 1 and device 2 are calculated according to the capacity ratio of device 1 and device 2, and the output power adjustment value of device 1 and device 2 are calculated according to the gains and proportional coefficients of device 1 and device 2. The integral process of device 1 is adjusted according to the output power adjustment value of device 1, and the integral process of device 2 is adjusted according to the output power adjustment value of device 1 and the initial power value. Finally, the steady-state output power of device 1 is 85KW, and the steady-state output power of device 2 is 75KW.

[0168] It should be understood that the size of the sequence number of each step in the above embodiment does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention. The above examples are intended to help those skilled in the art understand the embodiments of the present application, rather than to limit the embodiments of the present application to the specific numerical values ​​or specific scenarios illustrated. It is obvious that various equivalent modifications or changes can be made by those skilled in the art based on the above examples given, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0169] The present application also provides an electronic device, such as Fig.21 As shown, the electronic device 2 includes: at least one processor 20, a memory 21, and a computer program 22 stored in the memory 21 and executable on at least one processor 20. When the processor 20 executes the computer program, the steps in any of the above-mentioned method embodiments are implemented, or when the processor 20 executes the computer program, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0170] Exemplarily, the computer program may be divided into one or more modules / units, one or more modules / units are stored in a memory and executed by a processor to complete the present application. One or more modules / units may be a series of computer program instruction segments capable of completing a specific function, and the instruction segments are used to describe the execution process of the computer program in an electronic device.

[0171] Those skilled in the art will understand that Fig.21 These are merely examples of electronic devices and do not constitute a limitation of the electronic device. The electronic device may include more or fewer components than those shown in the figure, or a combination of certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0172] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0173] The memory may be an internal storage unit of an electronic device, such as a hard disk or memory of the electronic device. The memory may also be an external storage device of the electronic device, such as a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device. Furthermore, the memory may also include both an internal storage unit of the electronic device and an external storage device.

[0174] An embodiment of the present application further provides a readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0175] An embodiment of the present application provides a computer program product. When the computer program product is run on an electronic device, a mobile terminal can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0176] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device that can carry the computer program code to the camera / terminal device, a recording medium, a computer memory, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0177] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0178] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0179] In the embodiments provided in the present application, it should be understood that the disclosed devices / equipment and methods can be implemented in other ways. For example, the device / equipment embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0180] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0181] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A PWM converter, characterized in that: include: A PI controller, used for outputting power based on integral control and proportional control when the PWM converter is switched to the grid; The PI controller is also configured as: Determining an output power adjustment value of the PWM converter, wherein the output power adjustment value is obtained based on a gain of the PWM converter and a proportional coefficient of the proportional control; The output value of the integral control is adjusted by the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

2. The PWM converter according to claim 1, characterized in that: The PI controller determines the output power adjustment value of the PWM converter and is configured as follows: The gain of the PWM converter is obtained, the gain of the PWM converter is subtracted from the proportional coefficient to obtain a difference, and the inverse of the difference is taken to obtain an output power adjustment value.

3. The PWM converter according to claim 2, characterized in that: The PI controller obtains the gain of the PWM converter and is configured as follows: Acquire a gain coefficient of the PWM converter and a rated capacity of the PWM converter, and multiply the gain coefficient by the rated capacity to obtain a gain of the PWM converter; Alternatively, the total gain of the grid-connected PWM converter and the proportion of the PWM converter in the total rated capacity of the grid-connected PWM converter are obtained, and the gain of the PWM converter is obtained by multiplying the total gain by the proportion.

4. The PWM converter according to claim 1, characterized in that: The PI controller adjusts the output value of the integral control by the output power adjustment value and then feeds it back to the input end of the integral control, and is configured as follows: Receiving a bus voltage value and a bus reference voltage value and calculating a bus voltage difference; The output value of the integral control is multiplied by the output power adjustment value to obtain a first feedback value, and the bus voltage difference is subtracted from the first feedback value to obtain an input value for the integral control.

5. The PWM converter according to any one of claims 1 to 4, characterized in that: The PI controller determines the output power regulation value of the PWM converter and is further configured as follows: Determine an initial power value of the PWM converter, wherein the initial power value is obtained based on an operating state of the PWM converter; The output value of the integral control is adjusted by the initial power value and the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

6. The PWM converter according to claim 5, characterized in that: When the PWM converter performs rectification, the PI controller determines an initial power value of the PWM converter and is configured as follows: An average load rate of the PWM converter and a rated capacity of the PWM converter are obtained, and the initial power value is obtained by multiplying the average load rate by the rated capacity.

7. The PWM converter according to claim 5, characterized in that: When the PWM converter is connected to the energy storage module, the PI controller determines the initial power value of the PWM converter and is configured as follows: Acquire the SOC reference value and the SOC value of the energy storage module, and multiply the difference between the SOC reference value and the SOC value by a preset constant to obtain the initial power value; Alternatively, when the PWM converter is connected to an adjustable load, the PI controller determines an initial power value of the PWM converter and is configured as follows: The rated power of the adjustable load or the average power within a preset time is set as the initial value of the PWM converter.

8. The PWM converter according to claim 5, characterized in that: The PI controller adjusts the output value of the integral control by the initial power value and the output power adjustment value and then feeds it back to the input end of the integral control, and is configured as follows: Receiving a bus voltage value and a bus reference voltage value and calculating a bus voltage difference; After subtracting the output value of the integral process in the PI control from the initial power value, the resultant value is multiplied by the output power adjustment value to obtain a second feedback value, and then the bus voltage difference value is subtracted from the second feedback value to serve as the input value of the integral process.

9. A control method for a PWM converter, characterized in that: The method comprises the following steps: When the PWM converter performs grid-connected switching and outputs power based on integral control and proportional control, determining an output power adjustment value of the PWM converter, wherein the output power adjustment value is obtained based on a gain of the PWM converter and a proportional coefficient of the proportional control; The output value of the integral control is adjusted by the output power adjustment value and then fed back to the input end of the integral control to perform weighted distribution on the output power of the PWM converter.

10. A PWM converter grid-connected system, characterized in that: It comprises a PWM converter as claimed in any one of claims 1 to 8.

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