Electric appliance assembly, topological structure of electric energy management type network construction converter and control method of topological structure of electric energy management type network construction converter

Abstract

The invention discloses an electric appliance assembly, a topological structure of an electric energy management type networking converter and a control method, and relates to the technical field of power electronic conversion. The electric energy management type network construction converter comprises a cascade compensation structure and a high-voltage direct-hanging network construction control structure, and the method comprises the steps that firstly, a preset voltage is constructed on the basis of the high-voltage direct-hanging network construction control structure, the preset voltage takes a load demand as a reference, and then on a middle-high voltage power supply line, the load demand is calculated; the voltage deviation of the preset voltage is compensated based on the cascade compensation structure, target voltage is obtained, the target voltage meets the load requirement, and finally the power supply system is controlled based on the target voltage. The technical problems of unstable power supply and poor electric energy quality in a new energy direct connection load power supply scene in the prior art are solved.

Description

Technical Field

[0001] This application relates to the field of power electronic conversion technology, and more specifically, to an electrical component, a topology of a power management grid converter, and a control method thereof. Background Technology

[0002] In existing technologies, traditional grid-connected equipment cannot effectively integrate power quality management, especially in scenarios with a high proportion of direct power supply from renewable energy sources. When there is coupling between the renewable energy source and the load side, the fluctuation of renewable energy output directly affects the frequency and voltage stability of the power supply network, thereby impacting power quality. Furthermore, renewable energy grid connection typically employs a grid-following control mode, which directly limits the maximum power output of renewable energy, thus hindering efficient absorption.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This application provides an electrical component, a topology of a power management grid converter, and a control method to at least solve the technical problems of unstable power supply and poor power quality in the scenario of direct power supply to new energy loads.

[0005] According to one aspect of the embodiments of this application, an electrical component is provided, including: a series converter, a parallel converter, a DC bus filter capacitor, an energy storage device, and a compensation capacitor; the parallel converter is used to construct a preset voltage; the DC bus filter capacitor is connected in parallel with the parallel converter to stabilize the DC bus voltage; the energy storage device is connected in parallel with the DC bus filter capacitor to provide additional power support; the series converter is connected in series with the energy storage device to manage power quality; and the compensation capacitor is connected in series with the series converter to compensate for voltage deviations of the preset voltage.

[0006] Furthermore, the series converter includes a first bridge arm and a second bridge arm, and the parallel converter includes a second bridge arm and a third bridge arm, wherein the first bridge arm and the second bridge arm are connected in series, and the second bridge arm and the third bridge arm are connected in parallel. The first bridge arm, the second bridge arm, and the third bridge arm are used together to control the voltage and current.

[0007] Furthermore, the parallel converter and the energy storage device are cascaded to form a high-voltage direct-connection grid control structure, which is used to construct a preset voltage.

[0008] Furthermore, the compensation capacitor is also used to cascade the series converter with the medium and high voltage power supply line to form a cascaded compensation structure, which is used to compensate for the voltage deviation of the preset voltage.

[0009] According to one aspect of the embodiments of this application, a topology of a power management grid converter is provided, including: a plurality of electrical components, wherein the plurality of electrical components are connected in parallel with each other.

[0010] According to one aspect of the embodiments of this application, a control method for a power management grid-connected converter is provided. The power management grid-connected converter includes a cascaded compensation structure and a high-voltage direct-connection grid control structure. The method includes: constructing a preset voltage based on the high-voltage direct-connection grid control structure, wherein the preset voltage is based on load demand; compensating for voltage deviation of the preset voltage on a medium- or high-voltage power supply line based on the cascaded compensation structure to obtain a target voltage, wherein the target voltage meets the load demand; and controlling the power supply system based on the target voltage.

[0011] Furthermore, the control method for power management grid converters also includes: simulating the mechanical and electromagnetic transient processes of a synchronous generator using a virtual synchronous machine control method, wherein the mechanical transient process is used to simulate the dynamic process of rotor motion, and the electromagnetic transient process is used to simulate the dynamic process of electromagnetic torque; establishing active power control equations based on the mechanical transient process, and establishing reactive power control equations based on the electromagnetic transient process, wherein the active power control equations are used to simulate the frequency response characteristics of the synchronous generator, and the reactive power control equations are used to simulate the voltage regulation characteristics of the synchronous generator.

[0012] Furthermore, the control method for the power management grid-connected converter also includes: acquiring the port voltage of the high-voltage bus to obtain a first sampled voltage value; under virtual synchronous machine control mode, determining a first power angle and a first voltage amplitude based on the first sampled voltage value and the expected voltage value, wherein the first power angle is used to adjust the output of active power and the first voltage amplitude is used to adjust the output of reactive power; determining a first control signal according to the first power angle and the first voltage amplitude, wherein the first control signal is used to control the operating state of the parallel converter; and under carrier phase-shift modulation mode, determining the high-voltage direct-connected grid control structure based on the first control signal, the parallel converter, and the energy storage device.

[0013] Furthermore, the control method for the power management grid converter also includes: acquiring the second sampled voltage value at the common grid connection point; determining the voltage deviation based on the second sampled voltage value and the rated voltage value; determining the second power angle and the second voltage amplitude based on the voltage deviation under virtual synchronous machine control mode, wherein the second power angle is used to adjust the output of active power and the second voltage amplitude is used to adjust the output of reactive power; generating a second control signal for the series converter based on the second power angle and the second voltage amplitude, wherein the second control signal is used to adjust the output of the compensation capacitor; and determining the cascaded compensation structure based on the second control signal, the series converter, and the medium- and high-voltage power supply lines.

[0014] Furthermore, the power management grid-connected converter includes multiple electrical components, and the control method of the power management grid-connected converter further includes: controlling the carrier phase offset between any electrical component and adjacent electrical components by a preset angle; performing phase shift processing on the first control signal based on the preset angle to obtain a third control signal; and controlling any electrical component based on the second control signal and the third control signal.

[0015] According to one aspect of the embodiments of this application, a control device for a power management grid converter is provided, comprising: a construction module for constructing a preset voltage based on a high-voltage direct-connection grid control structure, wherein the preset voltage is based on load demand; a compensation module for compensating the voltage deviation of the preset voltage on medium- and high-voltage power supply lines based on a cascaded compensation structure to obtain a target voltage, wherein the target voltage meets the load demand; and a control module for controlling the power supply system based on the target voltage.

[0016] According to another aspect of the embodiments of this application, an electronic device is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the methods in various embodiments of this application when it runs.

[0017] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the computer-readable storage medium is located to perform the methods of various embodiments of this application.

[0018] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program that, when executed by a processor, implements the methods of various embodiments of this application.

[0019] In this embodiment, a preset voltage is first constructed based on a high-voltage direct-connection grid control structure, with the preset voltage based on load demand. Then, on medium- and high-voltage power supply lines, the voltage deviation of the preset voltage is compensated based on a cascaded compensation structure to obtain a target voltage that meets load demand. Finally, the power supply system is controlled based on the target voltage. Thus, this application achieves the goal of stabilizing the grid-connected voltage of new energy sources and the voltage of medium- and high-voltage power supply lines, thereby realizing the technical effects of improving the absorption capacity of new energy sources, ensuring power quality, and enhancing system stability. This solves the technical problems of unstable power supply and poor power quality in existing technologies for scenarios where new energy sources are directly connected to loads. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 This is a topology diagram of a power management grid converter according to an embodiment of this application;

[0022] Figure 2 This is a topology diagram of another power management grid converter according to an embodiment of this application;

[0023] Figure 3 This is a flowchart of a control method for a power management grid converter according to an embodiment of this application;

[0024] Figure 4 This is an optional virtual synchronizer control block diagram according to an embodiment of this application;

[0025] Figure 5 This is a flowchart of an optional new energy side-cascade network control method according to an embodiment of this application;

[0026] Figure 6 This is a flowchart of an optional load-side cascaded network control method according to an embodiment of this application;

[0027] Figure 7 This is an optional compensation vector diagram according to an embodiment of this application;

[0028] Figure 8 This is a diagram of an optional electrical component topology modulation strategy according to an embodiment of this application;

[0029] Figure 9 This is a structural block diagram of a control device for a power management grid converter according to an embodiment of this application. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] According to an embodiment of this application, an embodiment of a control method for a power management grid converter is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] Figure 1 This is a topology diagram of a power management grid converter according to an embodiment of this application, such as... Figure 1 As shown, the topology 100 of the power quality management grid converter includes: multiple phase converter modules 101, a new energy side 103, and a load side 105. Each phase converter module 101 includes: multiple electrical components 1011, which are connected in parallel. Each electrical component 1011 includes: a series converter, a parallel converter, a DC bus filter capacitor, an energy storage device, and a compensation capacitor; the parallel converter is used to construct a preset voltage; the DC bus filter capacitor is connected in parallel with the parallel converter to stabilize the DC bus voltage; the energy storage device is connected in parallel with the DC bus filter capacitor to provide additional power support; the series converter is connected in series with the energy storage device to manage power quality; and the compensation capacitor is connected in series with the series converter to compensate for voltage deviations of the preset voltage.

[0034] In this embodiment, the series converter includes a first bridge arm and a second bridge arm, and the parallel converter includes a second bridge arm and a third bridge arm. The first and second bridge arms are connected in series, and the second and third bridge arms are connected in parallel. The first, second, and third bridge arms are used together to control the voltage and current. The parallel converter is cascaded with an energy storage device to form a high-voltage direct-connection grid control structure, which is used to construct a preset voltage. A compensation capacitor is also used to cascade the series converter with a medium- and high-voltage power supply line to form a cascaded compensation structure, which is used to compensate for voltage deviations of the preset voltage.

[0035] Figure 2 This is a topology diagram of another power management grid-connected converter according to an embodiment of this application. The topology of the power management grid-connected converter in the scenario of direct connection of new energy power consumption is as follows: Figure 2 As shown, CA1, CA2, ..., CAn are n compensation capacitors; A1a, A1b, A1c are the a-arm, b-arm, and c-arm of the first submodule, respectively; A2a, A2b, A2c are the a-arm, b-arm, and c-arm of the second submodule, respectively; Ana, Anb, Anc are the a-arm, b-arm, and c-arm of the nth submodule, respectively; Q11, ..., Q16 are the 6 power switches of the first submodule; Q21, ..., Q26 are the 6 power switches of the second submodule; Qn1, ..., Qn6 are the 6 power switches of the nth submodule; L1, ..., L... n These are the inductors in the n sub-modules, and AC / DC refers to the AC / DC converter.

[0036] Furthermore, each phase converter module (phase A, phase B, phase C) is composed of multiple electrical components connected in series. These electrical components can be Unified Power Quality Conditioners (UPQCs). The electrical components consist of a parallel converter, a series converter, a DC bus filter capacitor, an energy storage device, and a compensation capacitor. The parallel converter is composed of the third bridge arm c and the second bridge arm b, while the series converter is composed of the first bridge arm a and the second bridge arm b. That is, the parallel and series converters share the second bridge arm b. The state equation of the topology can be expressed as:

[0037]

[0038] in, This refers to the voltage at the output of the series converter. The voltage at the output of the parallel converter. and These represent the rates of change of current through the inductors in phases A and C, respectively. , and These are the instantaneous voltages of phases A, B, and C in a three-phase circuit. and It represents the inductance in the circuit.

[0039] For example, since the output power of a photovoltaic power station is affected by external conditions such as sunlight intensity and ambient temperature, exhibiting inherent fluctuations and intermittency, to ensure that the renewable energy side can provide stable voltage and frequency support, the energy storage devices on the DC bus are connected in parallel for grid control. A voltage reference is constructed with the goal of providing sufficient adjustment margin for the photovoltaic power station to achieve maximum power output. Through cascading, the voltage is superimposed and raised, intelligently constructing and maintaining a stable voltage reference, thereby ensuring the voltage stability of the entire renewable energy access point. This control not only effectively smooths out random fluctuations in renewable energy output and maximizes resource utilization, but also avoids potential impacts and damages on load-side electrical equipment caused by fluctuations on the renewable energy side, ensuring the continuity and reliability of power supply.

[0040] When renewable energy is transmitted to the load side via transmission lines, line impedance can cause voltage drops and power losses. To ensure that the load-side voltage operates accurately and stably at its rated value and to achieve comprehensive voltage compensation, the proposed topology connects the series-connected inverter units of multiple electrical components in each phase. Based on the actual voltage at the load side, the energy storage devices on the DC bus are controlled by a parallel converter, and voltage superposition and boosting are achieved through compensation capacitors. This not only provides a wide-range, high-precision voltage compensation capability and significantly suppresses voltage sags and swells, but also greatly improves the power supply quality and operational reliability of highly sensitive loads on the load side.

[0041] In this embodiment, the new energy side achieves direct grid connection at high voltage by cascading parallel converters, significantly improving system efficiency while reducing equipment costs. On the load side, series converters are cascaded, so each electrical component only needs to withstand a portion of the total system voltage. This not only enables high voltage levels and low voltage stress, better meeting the needs of medium- and high-voltage scenarios, but also provides high reliability and fault tolerance. Furthermore, this application can improve output waveform quality and reduce harmonic content. Energy storage devices on the DC bus provide power support to both the new energy side and the load side, enabling grid control and thus achieving power decoupling between the source and load, preventing fluctuations on one side from affecting the other.

[0042] Figure 3 This is a flowchart of a control method for a power management grid converter according to an embodiment of this application, such as... Figure 3 As shown, the method includes the following implementation steps:

[0043] Step S30: Construct a preset voltage based on the high-voltage direct-connection grid control structure, wherein the preset voltage is based on the load demand;

[0044] Step S32: On the medium- and high-voltage power supply line, the voltage deviation of the preset voltage is compensated based on the cascaded compensation structure to obtain the target voltage, wherein the target voltage meets the load requirements.

[0045] Step S34: Control the power supply system based on the target voltage.

[0046] In this embodiment of the application, the construction of a preset voltage based on the high-voltage direct-connection grid control structure can be understood as the energy storage device in the system being controlled by a parallel converter, simulating the characteristics of a synchronous generator in the form of a virtual synchronous generator (VSG), providing the necessary inertia and damping, and constructing a preset voltage level (i.e., voltage reference) according to the load demand.

[0047] On medium- and high-voltage power supply lines, a cascaded compensation structure is used to compensate for voltage deviations of a preset voltage to obtain the target voltage. This can be understood as follows: when the voltage or frequency of the output from the high-voltage directly connected renewable energy generation unit fluctuates, or when voltage drops or rises are caused by line impedance, the series converter dynamically compensates through the cascaded compensation structure. Each electrical component independently adjusts its output compensation voltage based on its own energy storage state and the line voltage deviation. The compensation voltages are superimposed in time and space, acting together on the medium- and high-voltage power supply line to offset voltage deviations, ultimately obtaining a more stable and deviation-free target voltage that meets load requirements. This not only ensures the stability of the line voltage but also effectively addresses power quality issues such as voltage sags, swells, and harmonic voltages.

[0048] Controlling the power supply system based on the target voltage can be understood as adjusting various components of the power supply system according to the target voltage, including but not limited to new energy power generation units, energy storage systems, and power distribution on the load side.

[0049] As can be seen, through the above steps, a preset voltage is first constructed based on the high-voltage direct-connection grid control structure. Then, on the medium- and high-voltage power supply lines, the voltage deviation of the preset voltage is compensated based on the cascaded compensation structure to obtain the target voltage that meets the load requirements. Finally, the power supply system is controlled based on the target voltage. Therefore, this application achieves the goal of stabilizing the grid-connected voltage of new energy sources and the voltage of medium- and high-voltage power supply lines, thereby realizing the technical effects of improving the absorption capacity of new energy sources, ensuring power quality, and enhancing system stability. This solves the technical problems of unstable power supply and poor power quality in existing technologies for new energy direct-connection load scenarios.

[0050] Furthermore, the control method for power management grid converters also includes the following execution steps:

[0051] Step S36: The mechanical transient process and electromagnetic transient process of the synchronous generator are simulated by using a virtual synchronous machine control method. The mechanical transient process is used to simulate the dynamic process of rotor motion, and the electromagnetic transient process is used to simulate the dynamic process of electromagnetic torque.

[0052] Step S38: Establish active power control equations based on mechanical transient processes and reactive power control equations based on electromagnetic transient processes. The active power control equations are used to simulate the frequency response characteristics of the synchronous generator, and the reactive power control equations are used to simulate the voltage regulation characteristics of the synchronous generator.

[0053] In this embodiment, the mechanical transient process involves simulating the inertial motion of a synchronous generator rotor, i.e., how the rotor's mass and rotational speed affect the dynamic response of the system frequency. By incorporating the rotor's motion equations, the VSG can reflect the energy stored in the system and the inertial response resulting from rotor rotation. When the active power in the system changes (such as a sudden increase or decrease in load), the converter under VSG control can provide brief frequency support, similar to a conventional generator, avoiding drastic fluctuations in the system frequency.

[0054] Electromagnetic transient processes focus on simulating changes in the electromagnetic torque within a synchronous generator, specifically how the generator's voltage and current output are adjusted through the interaction of electromagnetic induction and magnetic fields. Under VSG control, the converter, by incorporating an electromagnetic transient model, can simulate armature reaction, magnetic saturation, and other electromagnetic effects, thereby maintaining a stable voltage level in the system. When grid disturbances occur, the VSG-controlled converter can rapidly adjust its output voltage and current to maintain grid voltage stability and prevent voltage collapse.

[0055] The active power control equation is based on mechanical transient processes and is used to manage the frequency response of the converter. Through the active power control equation, the converter can adjust its output active power according to changes in the system frequency to support system frequency stability. When the system frequency is lower than a preset value, the converter increases its output to compensate for the missing active power; conversely, it reduces its output to prevent excessive frequency rise. In other words, the active power control equation simulates the frequency response characteristics of a synchronous generator.

[0056] Reactive power control equations are equations based on electromagnetic transient processes used to manage the voltage support capability of a converter. Through these equations, the converter can adjust its output reactive power to maintain or restore the grid voltage to a predetermined level. When the grid voltage drops, the converter provides additional reactive power to boost the voltage; when the voltage is too high, it absorbs excess reactive power. The reactive power control equations simulate the voltage regulation characteristics of a synchronous generator.

[0057] For example, Figure 4This is an optional virtual synchronizer control block diagram according to an embodiment of this application, such as... Figure 4 As shown, where, P n is the reference value for active power. P e represents the actual output active power. w 0 is the rated angular frequency. K d The active frequency damping coefficient is... J Let be the virtual moment of inertia, and s be the Laplace operator. θ v For virtual power angle, Q n is the reference value for reactive power. Q e represents the actual output reactive power. K q U0 represents the reactive voltage regulation gain, and U0 represents the rated voltage amplitude. V v This represents the virtual voltage output amplitude.

[0058] To enable the converter in this application to possess the inertial damping characteristics of a synchronous generator, considering electromechanical transient processes, a virtual synchronous machine control method is selected to simulate the mechanical and electromagnetic transient processes of a synchronous generator. The active power control and reactive power equations are as follows:

[0059]

[0060] in, w Angular frequency, U This is the voltage amplitude output value. J For virtual rotational inertia, K d The active frequency damping coefficient is... The active frequency is the dynamic reference angular frequency. P n is the reference value for active power. P e represents the actual output active power. τ for Q - U The proportion coefficient of the branch road, K q For reactive voltage regulation gain, This is the dynamic reference amplitude of reactive voltage. U This is the reference amplitude for the output voltage. Q n is the reference value for reactive power. Q e represents the actual output reactive power.

[0061] It can be seen that the VSG control strategy, by simulating the characteristics of traditional generators, promotes the smooth grid connection of new energy sources and improves the operating efficiency and safety of the power system.

[0062] Furthermore, the control method for power management grid converters also includes the following execution steps:

[0063] Step S301: Obtain the port voltage of the high-voltage bus to get the first sampled voltage value;

[0064] Step S302: Under the virtual synchronous machine control mode, based on the first sampled voltage value and the expected voltage value, determine the first power angle and the first voltage amplitude, wherein the first power angle is used to adjust the output of active power and the first voltage amplitude is used to adjust the output of reactive power.

[0065] Step S303: Determine the first control signal based on the first power angle and the first voltage amplitude, wherein the first control signal is used to control the operating state of the parallel converter;

[0066] Step S304: Under carrier phase-shift modulation, determine the high-voltage direct-connection grid control structure based on the first control signal, the parallel converter, and the energy storage device.

[0067] In this embodiment, the first sampled voltage value refers to the voltage signal of the high-voltage bus port collected in real time, which reflects the actual voltage status of the current power grid.

[0068] The expected voltage value is the set target value of the grid voltage, used to represent the stable voltage level of the system.

[0069] The first power angle refers to the relative angular difference between the phase of the converter's output voltage and the phase of the grid voltage. For example, when the power angle is greater than zero, the converter tends to output active power; when the power angle is less than zero, the converter absorbs active power. By adjusting the first power angle, the mechanical characteristics of a traditional synchronous generator can be simulated, thereby providing dynamic frequency and power support to the grid.

[0070] The first voltage amplitude is the magnitude of the converter's output voltage, typically compared to the grid's voltage reference value. In VSG control, adjusting the first voltage amplitude controls the reactive power exchange between the converter and the grid, thus affecting the stability and quality of the grid voltage. When the converter's output voltage amplitude is higher than the grid voltage, it will output reactive power; conversely, it will absorb reactive power. By controlling the first voltage amplitude, the converter can provide voltage support to the grid, similar to the electrical characteristics of a synchronous generator.

[0071] The first control signal is a command signal calculated based on the converter control strategy, used to directly guide the switching states of the internal switching devices of the converter. The first control signal integrates information from the first power angle and the first voltage amplitude, and generates the converter's switching signal through pulse width modulation (PWM) or other modulation techniques, thereby controlling the voltage waveform and frequency of the converter's output. The first control signal serves as a bridge connecting advanced control strategies such as virtual synchronous machines with the converter hardware, ensuring that the converter interacts with the power grid according to the expected electrical characteristics.

[0072] Carrier phase-shift modulation is a modulation technique commonly used in multilevel inverters. By changing the carrier phase of each electrical component, the switching signals of each electrical component are evenly distributed in time, thereby reducing switching losses and improving the waveform quality of the output voltage.

[0073] Obtaining the port voltage of the high-voltage bus and getting the first sampled voltage value can be understood as using sensors to monitor the voltage of the high-voltage bus in real time, and converting the measured voltage into a digital signal or processing it into a signal form that can be recognized by the control system, thereby obtaining the first sampled voltage value.

[0074] Under the virtual synchronous machine control mode, determining the first power angle and the first voltage amplitude based on the first sampled voltage value and the expected voltage value can be understood as follows: based on the control logic of the virtual synchronous machine, the first sampled voltage value is compared with the voltage value expected by the system, and then the control parameters, namely the first power angle and the first voltage amplitude, are calculated according to the deviation.

[0075] Determining the first control signal based on the first power angle and the first voltage amplitude can be understood as mapping the first power angle and the first voltage amplitude into a modulated wave, then comparing it with the carrier wave, and determining the first control signal through pulse width modulation or other modulation techniques.

[0076] Under the carrier phase-shift modulation method, determining the high-voltage direct-connection grid control structure based on the first control signal, the parallel converter, and the energy storage device can be understood as follows: based on the determination of the first control signal, the parallel converter is precisely controlled through carrier phase-shift modulation technology, while the charging and discharging state of the energy storage device is considered to determine the high-voltage direct-connection grid control structure.

[0077] For example, Figure 5 This is a flowchart of an optional new energy-side cascaded grid control method according to an embodiment of this application. To enable the energy storage device to construct the new energy grid connection port voltage through cascaded parallel converters, the specific control strategy is as follows: Figure 5As shown, the port voltage of the high-voltage busbar for new energy is collected, and the sampled value and expected value are input into the VSG control to output the power angle and the voltage amplitude of the reactive power control output. The switching signal of each module (i.e., electrical component) is generated by comparing its own phase-shifted carrier wave with the common modulation wave. The cascaded H-bridge is controlled by carrier phase-shift modulation, and the modulation waves of the three phases can be obtained separately using the following formulas:

[0078]

[0079] in, This is the compensation voltage for phase A submodule. This is the compensation voltage for the B-phase submodule. This is the compensation voltage for the C-phase submodule. To determine the maximum output compensation voltage amplitude of the submodule, each electrical component in each phase of the H-bridge is assigned a triangular carrier wave with the same frequency and amplitude. The carrier phases of adjacent electrical components in each phase of the H-bridge are sequentially offset by an angle. It can be calculated using the following formula:

[0080]

[0081] in, N This indicates the number of cascaded H-bridge submodules connected in series in each phase. Due to the staggered carrier phases, the switching states of each electrical component are evenly distributed over time, ensuring that the switching on and off times of each component are statistically equal within the fundamental period. This automatically balances the capacitor voltage without requiring an additional voltage sorting algorithm. The switching frequency of the output level is a fraction of the switching frequency of a single electrical component. N This increases the equivalent switching frequency by a factor of 1, making filtering easier and the output waveform quality better.

[0082] By controlling the modulation wave of the H-bridge electrical components, the operating state of the parallel converter is changed, thereby establishing a voltage reference through the charging and discharging of energy storage. Furthermore, establishing the voltage at the renewable energy port avoids the waste of solar resources caused by port voltage limitations during maximum power point tracking (MPPT) of photovoltaic systems.

[0083] It can be seen that in medium and high voltage power supply scenarios, the high voltage direct-connection grid control structure can directly realize the grid connection of new energy sources at high voltage levels, avoiding the complexity and losses of traditional transformer step-up grid connection, and improving the overall efficiency and economy of the system.

[0084] Furthermore, the control method for power management grid converters also includes the following execution steps:

[0085] Step S305: Obtain the second sampled voltage value of the common grid connection point;

[0086] Step S306: Determine the voltage deviation based on the second sampled voltage value and the rated voltage value;

[0087] Step S307: Under the virtual synchronous machine control mode, the second power angle and the second voltage amplitude are determined based on the voltage deviation, wherein the second power angle is used to adjust the output of active power and the second voltage amplitude is used to adjust the output of reactive power.

[0088] Step S308: Generate a second control signal for the series converter based on the second power angle and the second voltage amplitude, wherein the second control signal is used to adjust the output of the compensation capacitor;

[0089] Step S309: Determine the cascaded compensation structure based on the second control signal, the series converter, and the medium- and high-voltage power supply lines.

[0090] In this embodiment of the application, the second sampled voltage value refers to the voltage signal value collected in real time from the point of common coupling (PCC) and is used to reflect the real-time voltage status of the current power grid.

[0091] The rated voltage is the ideal voltage level that the system should maintain during normal operation.

[0092] The second power angle is a control parameter under virtual synchronous machine control, used to adjust the relative angle difference between the converter output voltage phase and the grid voltage phase. By controlling the second power angle, the mechanical characteristics of a synchronous generator can be simulated to achieve dynamic support for grid frequency and optimized power allocation.

[0093] The second voltage amplitude is the adjustment of the converter's output voltage under virtual synchronous machine control. The second voltage amplitude works in conjunction with the second power angle to control the reactive power exchange between the converter and the grid, thereby affecting the grid's voltage level.

[0094] The second control signal is calculated based on the second power angle and the second voltage amplitude, and is used to directly control the switching state of the internal switching devices of the series converter.

[0095] Obtaining the second sampled voltage value of the common grid connection point can be understood as using a sensor to collect voltage data from the common grid connection point in real time, and obtaining the current voltage value as the second sampled voltage value.

[0096] Determining the voltage deviation based on the second sampled voltage value and the rated voltage value can be understood as calculating the voltage deviation by comparing the second sampled voltage value with the pre-set rated voltage value of the power grid.

[0097] Under the virtual synchronous machine control mode, determining the second power angle and the second voltage amplitude based on the voltage deviation can be understood as dynamically adjusting the control parameters according to the calculated voltage deviation based on the virtual synchronous machine control strategy to obtain the second power angle and the second voltage amplitude.

[0098] The generation of a second control signal for the series converter based on the second power angle and the second voltage amplitude can be understood as generating a second control signal for driving the series converter based on the second power angle and the second voltage amplitude.

[0099] Determining the cascaded compensation structure based on the second control signal, the series converter, and the medium- and high-voltage power supply line can be understood as follows: on the medium- and high-voltage power supply line, the voltage deviation is compensated based on the second control signal and the series converter, thereby determining the cascaded compensation structure.

[0100] For example, Figure 6 This is a flowchart of an optional load-side cascaded network control method according to an embodiment of this application, such as... Figure 6 As shown, due to line impedance causing voltage drops and power losses in actual operation, power quality management is achieved through cascaded series converters to meet the power demands of highly sensitive loads. On the renewable energy side, the grid is constructed at the common grid connection point where the photovoltaic power plant outputs converge to achieve maximum power point tracking. Additionally, impedance losses exist in the lines, resulting in an error between the actual voltage transmitted to the load and the load's rated voltage. The load's rated voltage and the actual value transmitted to the load-side PCC point are input into the VSG control, which controls the three-phase modulation wave based on the output power angle and voltage amplitude. By changing the operating state of the series converter in each phase and module (i.e., electrical component), the charging and discharging power of the energy storage device on the DC bus of different electrical components can be independently adjusted according to demand, thereby achieving a stable load-side voltage through compensation capacitors CA1, CA2, ..., CAn. The compensation amount of each electrical component's series converter can be individually controlled and flexibly allocated according to the energy storage state on the DC bus, providing fault tolerance and reducing the stress on individual capacitors, thus extending the overall system life and improving stability.

[0101] Figure 7 This is an optional compensation vector diagram according to an embodiment of this application, such as... Figure 7 As shown, U LN The line voltage or phase voltage typically representing the load side refers to the actual voltage measured on the load side. U dvr To assess the extent of voltage sags, the system minimizes them through a compensation mechanism. U dvr This is to mitigate the impact of voltage sags on the load. U dvr_comThis is the compensation amount for voltage sags, which is the portion of the energy output from the converter used by the system to compensate for voltage sags in order to eliminate or mitigate them. U dvr_com Size and orientation depend on U dvr The specific values ​​and the voltage quality standards that the system needs to achieve. U e_shunt1 The compensation voltage used to represent the first electrical component is output by the compensation capacitor CA1. U e_shunt2 The compensation voltage used to represent the second electrical component is output by the compensation capacitor CA2. U e_shunt1 and U e_shunt2 Used to adjust or compensate the actual voltage on the load side. U LN To achieve the required voltage level. I L This is the load current before compensation. I' L This is the current on the load side after voltage compensation. I' L The degree of improvement depends on U dvr_com and U e_shunt（n） The effect of adjusting the compensation voltage. δ This typically represents the phase difference between the grid-connected voltage on the renewable energy side and the grid voltage in virtual synchronous machine control. In grid-connected control strategies, this is achieved by adjusting... δ This value can simulate the inertial damping characteristics of a synchronous generator, thereby regulating the power output of the converter. In scenarios involving grid connection of renewable energy generation, adjusting... δ It helps maintain the stability of power transmission and the synchronization of the grid frequency. This represents the phase angle between the compensation capacitor and the reference voltage (usually the grid voltage), used to describe the phase characteristics of the compensation output. In power quality management, this is achieved by controlling... It can precisely adjust the output of the compensation capacitor to offset fluctuations or distortions in the mains voltage, such as voltage dips and harmonics. The adjustment ensures that the compensation vector output of the compensation capacitors CA1, CA2, ..., CAn is correct. U e_shunt1 , U e_shunt2 The compensation direction is precisely matched with the actual needs, thereby achieving efficient power quality management.

[0102] It can be seen that the cascaded compensation structure not only improves the accuracy and range of voltage compensation, but also increases the redundancy and flexibility of the system, ensuring that the grid voltage can be effectively maintained under various operating conditions and meeting the power supply needs of highly sensitive loads.

[0103] Furthermore, the power management grid-connected converter includes multiple electrical components, and the control method for the power management grid-connected converter further includes the following execution steps:

[0104] Control the carrier phase offset between any electrical component and adjacent electrical components by a preset angle;

[0105] The first control signal is phase-shifted based on a preset angle to obtain the third control signal;

[0106] Control any electrical component based on the second and third control signals.

[0107] In this embodiment, controlling the carrier phase offset between any electrical component and its adjacent components by a preset angle can be understood as each electrical component receiving a carrier signal, and these carrier signals having different phases. In actual control, an electrical component is selected as a reference, and then a preset angle offset is added to the carrier signals of its adjacent electrical components. This offset angle is typically π / N This ensures that the carrier signals of all electrical components are evenly distributed in phase.

[0108] The third control signal is obtained by phase-shifting the first control signal based on a preset angle. This can be understood as shifting the first control signal by the same preset angle as the carrier signal to generate the third control signal. The generation of the third control signal ensures that the switching action of each electrical component is not only controlled by its own carrier signal, but also takes into account the coordination with adjacent components. This makes the output voltage of all electrical components in the overall system more orderly in time sequence, thereby improving the smoothness of the output waveform and reducing harmonic content.

[0109] Controlling any electrical component based on the second and third control signals can be understood as the electrical component determining the on and off times of its switching elements according to the second and third control signals. This control method enables each electrical component to perform optimized local switching control while adhering to the system objectives, ensuring that the output voltage matches the target command and maintaining waveform quality.

[0110] For example, Figure 8 This is a diagram illustrating an optional electrical component topology modulation strategy according to an embodiment of this application. Since the series and parallel converters in the electrical component share a second bridge arm, coupling exists. The modulation strategy for a single electrical component topology is as follows: Figure 8As shown, where, U L This is the load-side voltage. I L For load-side current, U dvr This is the output voltage of the series converter. U e This is the compensation voltage output by the series converter. I a For the A-phase current of the parallel converter, I c For the C-phase current of the parallel converter, U ab This refers to the output voltage between bridge arms a and b of the series converter. U dc This is the DC bus voltage. U cb This is the output voltage between the c-arm and b-arm of the parallel converter.

[0111] The modulation wave of the parallel converter can be obtained based on the grid control on the new energy side. Similarly, the modulation wave of the series converter can be obtained based on the grid control on the load side. By controlling one converter independently in the second bridge arm during two carrier cycles, while the other converter is locked out, sinusoidal pulse width modulation (SPWM) is achieved. SPWM modulation can reduce switching losses and simultaneously enable control of the submodule topology.

[0112] As can be seen, the above steps can achieve efficient control of the multilevel converter, especially in cascaded H-bridge topologies. Moreover, without requiring a large amount of hardware complexity, this application can generate high-quality multilevel voltage waveforms while maintaining system stability and high efficiency.

[0113] In this embodiment, a control device for a power management grid converter is also provided. This device is used to implement the above embodiments and preferred embodiments, and details already described will not be repeated. As used below, a "module" is a combination of software and / or hardware that can perform a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0114] Figure 9 This is a structural block diagram of a control device for a power management grid converter according to an embodiment of this application, such as... Figure 9As shown, the control device 900 of the power management grid converter includes: a construction module 901, used to construct a preset voltage based on the high-voltage direct-connection grid control structure, wherein the preset voltage is based on the load demand; a compensation module 902, used to compensate for the voltage deviation of the preset voltage on the medium- and high-voltage power supply lines based on a cascaded compensation structure to obtain a target voltage, wherein the target voltage meets the load demand; and a control module 903, used to control the power supply system based on the target voltage.

[0115] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located in the same processor; or, the above modules are located in different processors in any combination.

[0116] According to another aspect of the embodiments of this application, an electronic device is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the methods in various embodiments of this application when it runs.

[0117] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the computer-readable storage medium is located to perform the methods of various embodiments of this application.

[0118] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program that, when executed by a processor, implements the methods of various embodiments of this application.

[0119] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments and their optional implementations, and will not be repeated here.

[0120] In this application, the descriptions of the various embodiments have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection can be through some interfaces; the indirect coupling or communication connection between units or modules can be electrical or other forms.

[0122] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0123] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0124] If the integrated unit is implemented as 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 technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, ROM, RAM, portable hard drives, magnetic disks, or optical disks.

[0125] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An electrical component, characterized in that, include: Series converter, parallel converter, DC bus filter capacitor, energy storage device, compensation capacitor; The parallel converter is used to construct a preset voltage; The DC bus filter capacitor is connected in parallel with the parallel converter to stabilize the DC bus voltage. The energy storage device is connected in parallel with the DC bus filter capacitor to provide additional power support; The series converter is connected in series with the energy storage device and is used to improve power quality. The compensation capacitor is connected in series with the series converter and is used to compensate for the voltage deviation of the preset voltage.

2. The electrical component according to claim 1, characterized in that, The series converter includes a first bridge arm and a second bridge arm, and the parallel converter includes a second bridge arm and a third bridge arm, wherein the first bridge arm and the second bridge arm are connected in series, and the second bridge arm and the third bridge arm are connected in parallel, and the first bridge arm, the second bridge arm and the third bridge arm are used together to control the voltage and current.

3. The electrical component according to claim 1, characterized in that, The parallel converter is cascaded with the energy storage device to form a high-voltage direct-connection grid control structure, wherein the high-voltage direct-connection grid control structure is used to construct the preset voltage.

4. The electrical component according to claim 1, characterized in that, The compensation capacitor is also used to cascade the series converter with the medium- and high-voltage power supply line to form a cascaded compensation structure, wherein the cascaded compensation structure is used to compensate for the voltage deviation of the preset voltage.

5. A topology for a power management grid converter, characterized in that, include: A plurality of electrical components as described in any one of claims 1-4, wherein the plurality of electrical components are connected in parallel with each other.

6. A control method for a power management grid-connected converter, wherein the power management grid-connected converter comprises: A cascaded compensation structure and a high-voltage direct-connection grid control structure, characterized in that the method includes: A preset voltage is constructed based on the high-voltage direct-connection grid control structure, wherein the preset voltage is based on load demand; On medium- and high-voltage power supply lines, the voltage deviation of the preset voltage is compensated based on the cascaded compensation structure to obtain the target voltage, wherein the target voltage meets the load requirements; The power supply system is controlled based on the target voltage.

7. The control method according to claim 6, characterized in that, The method further includes: A virtual synchronous machine control method is used to simulate the mechanical and electromagnetic transient processes of a synchronous generator. The mechanical transient process is used to simulate the dynamic process of rotor motion, and the electromagnetic transient process is used to simulate the dynamic process of electromagnetic torque. An active power control equation is established based on the mechanical transient process, and a reactive power control equation is established based on the electromagnetic transient process. The active power control equation is used to simulate the frequency response characteristics of the synchronous generator, and the reactive power control equation is used to simulate the voltage regulation characteristics of the synchronous generator.

8. The control method according to claim 7, characterized in that, The method further includes: Obtain the port voltage of the high-voltage bus to get the first sampled voltage value; Under the virtual synchronous machine control mode, a first power angle and a first voltage amplitude are determined based on the first sampled voltage value and the expected voltage value, wherein the first power angle is used to adjust the output of active power and the first voltage amplitude is used to adjust the output of reactive power. A first control signal is determined based on the first power angle and the first voltage amplitude, wherein the first control signal is used to control the operating state of the parallel converter; Under carrier phase-shift modulation, the high-voltage direct-connection grid control structure is determined based on the first control signal, the parallel converter, and the energy storage device.

9. The control method according to claim 7, characterized in that, The method further includes: Obtain the second sampled voltage value at the common grid connection point; The voltage deviation is determined based on the second sampled voltage value and the rated voltage value; Under the virtual synchronous machine control mode, a second power angle and a second voltage amplitude are determined based on the voltage deviation, wherein the second power angle is used to adjust the output of active power and the second voltage amplitude is used to adjust the output of reactive power. A second control signal for the series converter is generated based on the second power angle and the second voltage amplitude, wherein the second control signal is used to adjust the output of the compensation capacitor; The cascaded compensation structure is determined based on the second control signal, the series converter, and the medium- and high-voltage power supply line.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, wherein the computer program is configured to execute the method described in any one of claims 6 to 9 when run on a computer or processor.

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