Compensation switching method and device and hybrid distribution transformer system

Abstract

The invention discloses a compensation switching method and device and a hybrid distribution transformer system. The method comprises the following steps: firstly, obtaining the current working mode of the hybrid distribution transformer system, wherein the current working mode comprises a compensation working mode and a non-compensation working mode; in the compensation working mode, the electromagnetic transformer is in a working state, and the power electronic converter is in a compensation state; in the non-compensation working mode, the electromagnetic transformer still works, and the power electronic converter is in a bypass state and does not work; then electric energy quality parameters in the current working mode are obtained; and finally, according to the electric energy quality parameters, determining that the next working mode of the hybrid distribution transformer system is a non-compensation working mode or a compensation working mode, and switching between the compensation working mode and the non-compensation working mode. According to the method, dynamic compensation and non-compensation switching can be realized according to different electric energy quality parameters, so that the electric energy quality is optimized, and the energy consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformers, and in particular relates to a compensation switching method, a device and a hybrid distribution transformer system. Background Art

[0002] An electromagnetic transformer is an electrical device based on the principle of electromagnetic induction. It generates an alternating magnetic field by passing an alternating current through the primary winding, which inducing a voltage in the secondary winding, achieving voltage regulation. Power electronic converters, on the other hand, utilize electronic switching elements (such as transistors and diodes) to efficiently control and convert electrical energy.

[0003] Hybrid distribution transformer systems combine the advantages of traditional electromagnetic transformers and power electronic converters. Their operating principle is that the electromagnetic transformer is responsible for main power transmission, while the power electronic converter provides dynamic compensation for low-power needs. This combination not only improves operational efficiency but also better meets user demands for power quality, thereby enhancing the overall performance of the distribution system. However, current applications primarily use electromagnetic transformers and power electronic converters simultaneously, without the ability to dynamically adjust them. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art and propose a compensation switching method for a hybrid distribution transformer. The method can dynamically realize the compensation and non-compensation switching of the hybrid distribution transformer according to different power quality parameters, thereby optimizing power quality and reducing energy consumption.

[0005] In a first aspect, the present invention provides a compensation switching method for a hybrid distribution transformer system, wherein the hybrid distribution transformer system includes an electromagnetic transformer and a power electronic converter, wherein the electromagnetic transformer and the power electronic converter are electrically connected. The method comprises the following steps:

[0006] Obtaining a current working mode of the hybrid distribution transformer system; the current working mode of the hybrid distribution transformer system includes a compensation working mode and a non-compensation working mode;

[0007] The compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in working compensation state; the non-compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in non-working bypass state.

[0008] Obtaining power quality parameters of the hybrid distribution transformer system in a current operating mode, and determining a next operating mode of the hybrid distribution transformer system based on the power quality parameters and the current operating mode;

[0009] Control the hybrid distribution transformer system to operate in the next working mode.

[0010] Furthermore, the power quality parameters include actual voltage value, actual reactive power value, and actual unbalance;

[0011] Determine the next operating mode of the hybrid distribution transformer system based on the power quality parameters and the current operating mode, including:

[0012] determining, based on the power quality parameters, whether a threshold value exceeds a range in a current operating mode of the hybrid distribution transformer system; and determining, based on whether the threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system, a next operating mode of the hybrid distribution transformer system;

[0013] Based on the power quality parameters, determine whether the hybrid distribution transformer system exceeds the threshold range in the current operating mode, including:

[0014] If the actual voltage value exceeds the target voltage threshold, or the actual reactive value exceeds the target reactive threshold, or the actual unbalance exceeds the target unbalance, it is determined that the hybrid distribution transformer system has a threshold exceeding range; or,

[0015] If the actual voltage value does not exceed the target voltage threshold, the actual reactive power value does not exceed the target reactive power threshold, and the actual unbalance does not exceed the target unbalance, it is determined that the hybrid distribution transformer system does not exceed the threshold range;

[0016] Determining a next operating mode of the hybrid distribution transformer system according to whether a threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system includes:

[0017] If the current working mode is the non-compensation working mode and the hybrid distribution transformer system has a threshold value exceeding the range, then determining that the next working mode of the hybrid distribution transformer system is the compensation working mode; or,

[0018] If the current working mode is the compensation working mode and the hybrid distribution transformer system does not exceed the threshold, the next working mode of the hybrid distribution transformer system is determined to be the non-compensation working mode.

[0019] Furthermore, controlling the hybrid distribution transformer system to operate in the next working mode specifically includes:

[0020] If the current working mode is the non-compensation working mode and the next working mode is the non-compensation working mode, the hybrid distribution transformer system is controlled to operate in the non-compensation working mode; or,

[0021] If the current working mode is the compensation working mode and the next working mode is the compensation working mode, the hybrid distribution transformer system is controlled to operate in the compensation working mode; or,

[0022] If the current working mode is the non-compensation working mode and the next working mode is the compensation working mode, the hybrid distribution transformer system is controlled to switch from the non-compensation working mode to the compensation working mode, and then the hybrid distribution transformer system is controlled to operate in the compensation working mode; or,

[0023] If the current working mode is the compensation working mode and the next working mode is the non-compensation working mode, the hybrid distribution transformer system is controlled to switch from the compensation working mode to the non-compensation working mode, and then the hybrid distribution transformer system is controlled to operate in the non-compensation working mode.

[0024] Furthermore, the hybrid distribution transformer system further includes a bypass device, which is provided between the electromagnetic transformer and the power electronic converter and is electrically connected to both the electromagnetic transformer and the power electronic converter;

[0025] Controlling the hybrid distribution transformer system to switch from a non-compensated operating mode to a compensated operating mode is achieved by controlling the bypass device to switch the power electronic converter from a non-operating bypass state to an operating compensation state;

[0026] Controlling the hybrid distribution transformer system to switch from a compensation working mode to a non-compensation working mode is achieved by controlling a bypass device to switch a power electronic converter from a working compensation state to a non-working bypass state.

[0027] Furthermore, the bypass device includes a load isolating switch and a thyristor; the load isolating switch and the thyristor are connected in parallel;

[0028] The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter;

[0029] The control of the rectifier-stage converter is jointly implemented by the rectifier-stage PI controller and the rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve DC power output; the control of the inverter converter is jointly implemented by the inverter-stage PI controller and the inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve AC power output;

[0030] Controlling the hybrid distribution transformer system to switch from a non-compensated operating mode to a compensated operating mode specifically includes the following steps:

[0031] Step A1: Detecting the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0032] If the compensation signal p2 = 1 and the compensation operation flag k2 = 0, then proceed to step A2; if the compensation signal p2 = 0, or the compensation operation flag k2 = 1, then re-detect the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0033] Step A2: Send an opening command to the load isolation switch in the closed state; and, control the rectifier stage PI controller to reset; and, control the rectifier stage PWM port to trigger; and, control the rectifier stage converter to work to stabilize the DC bus voltage to the reference voltage U dc ;

[0034] Step A3: Control the load isolation switch to operate in the first preset time period t_ on1 Open the switch to fully open the load isolating switch and allow the current to flow through the thyristor;

[0035] Step A4: controlling the thyristor not to trigger; and controlling the inverter-stage PI controller to reset; and controlling the inverter PWM port to trigger;

[0036] Step A5: Control the inverter converter to operate, and set the compensation operation flag k2 to 1, thereby switching from the non-compensation operation mode to the compensation operation mode.

[0037] Furthermore, the bypass device includes a load isolating switch and a thyristor; the load isolating switch and the thyristor are connected in parallel;

[0038] The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter;

[0039] The control of the rectifier-stage converter is jointly implemented by the rectifier-stage PI controller and the rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve DC power output; the control of the inverter converter is jointly implemented by the inverter-stage PI controller and the inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve AC power output;

[0040] Controlling the hybrid distribution transformer system to switch from a compensation mode to a non-compensation mode includes the following steps:

[0041] Step B1: Detecting the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0042] If the compensation signal p2 = 0 and the compensation operation flag k2 = 1, then proceed to step A2; if the compensation signal p2 = 1, or the compensation operation flag k2 = 0, then re-detect the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0043] Step B2: issuing a closing instruction to the load disconnect switch in the open state; and issuing a thyristor triggering signal;

[0044] Step B3: Control the load isolation switch to operate in the second preset time period t_ off1 Internal conduction to make the load isolation switch fully turned on and allow current to flow through the thyristor;

[0045] Step B4: controlling the blocking trigger of the inverter PWM port;

[0046] Step B5: Control the inverter converter to operate in the third preset time period t_ off2 Stop working to stabilize the DC bus voltage to the reference voltage U dc ;

[0047] Step B6: Control the latch triggering of the PWM port of the rectifier stage;

[0048] Step B7: Control the rectifier stage converter to stop working, and set the compensation operation flag k2 to 0, thereby switching from the compensation working mode to the non-compensation working mode.

[0049] In a second aspect, the present invention provides a compensation switching device for a hybrid distribution transformer system, wherein the hybrid distribution transformer system includes an electromagnetic transformer and a power electronic converter, wherein the electromagnetic transformer and the power electronic converter are electrically connected, and the device includes:

[0050] A first acquiring unit is configured to acquire a current operating mode of the hybrid distribution transformer system; the current operating mode of the hybrid distribution transformer system includes a compensation operating mode and a non-compensation operating mode;

[0051] The compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in working compensation state; the non-compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in non-working bypass state.

[0052] a second acquisition unit, connected to the first acquisition unit, for acquiring power quality parameters of the hybrid distribution transformer system in a current working mode;

[0053] a mode determination unit connected to the second acquisition unit, and configured to determine a next operating mode of the hybrid distribution transformer system according to the power quality parameter and the current operating mode;

[0054] The control unit is connected to the mode determination unit and is used to control the hybrid distribution transformer system to operate according to the next working mode.

[0055] Furthermore, the power quality parameters include actual voltage value, actual reactive power value, and actual unbalance;

[0056] The mode determination unit includes:

[0057] A first determining module is connected to the second acquiring unit and is used to determine whether a threshold value exceeds a range in the hybrid distribution transformer system in a current operating mode according to the power quality parameter;

[0058] a second determining module, connected to the first determining module, for determining a next operating mode of the hybrid distribution transformer system according to whether a threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system;

[0059] The first determination module includes:

[0060] A first determining submodule is connected to the second acquiring unit and is configured to determine that a threshold value exceeds a range in the hybrid distribution transformer system when the actual voltage value exceeds a target voltage threshold, or the actual reactive power value exceeds a target reactive power threshold, or the actual unbalance exceeds a target unbalance;

[0061] a second determining submodule, connected to the second acquiring unit, for determining that there is no threshold exceeding range in the hybrid distribution transformer system when the actual voltage value does not exceed the target voltage threshold, the actual reactive power value does not exceed the target reactive power threshold, and the actual unbalance does not exceed the target unbalance;

[0062] The second determination submodule includes:

[0063] A third determining submodule, connected to the first determining submodule, is configured to determine that the next operating mode of the hybrid distribution transformer system is a compensation operating mode when the current operating mode is a non-compensation operating mode and a threshold value of the hybrid distribution transformer system exceeds a range;

[0064] The fourth determination submodule is connected to the second determination submodule and is used to determine that the next working mode of the hybrid distribution transformer system is the non-compensation working mode when the current working mode is the compensation working mode and there is no threshold exceeding the range in the hybrid distribution transformer system.

[0065] Furthermore, the control unit includes:

[0066] a first control unit connected to the mode determination unit, configured to control the hybrid distribution transformer system to operate in the non-compensation working mode when the current working mode is the non-compensation working mode and the next working mode is the non-compensation working mode;

[0067] a second control unit connected to the mode determination unit, configured to control the hybrid distribution transformer system to operate in the compensation working mode when the current working mode is the compensation working mode and the next working mode is the compensation working mode;

[0068] a third control unit, connected to the mode determination unit, configured to control the hybrid distribution transformer system to switch from the non-compensation working mode to the compensation working mode when the current working mode is the non-compensation working mode and the next working mode is the compensation working mode, and then control the hybrid distribution transformer system to operate in the compensation working mode;

[0069] The fourth control unit is connected to the mode determination unit and is used to control the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode when the current working mode is the compensation working mode and the next working mode is the non-compensation working mode, and then control the hybrid distribution transformer system to operate in the non-compensation working mode.

[0070] Furthermore, the hybrid distribution transformer system further includes a bypass device, which is provided between the electromagnetic transformer and the power electronic converter and is electrically connected to both the electromagnetic transformer and the power electronic converter;

[0071] The third control unit includes a first switching module, the first switching module is used to control the hybrid distribution transformer system to switch from a non-compensation working mode to a compensation working mode;

[0072] The hybrid distribution transformer system is controlled to switch from a non-compensation working mode to a compensation working mode by controlling a bypass device to switch the power electronic converter from a non-working bypass state to a working compensation state.

[0073] The fourth control unit includes a second switching module, and the second switching module is used to control the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode;

[0074] The hybrid distribution transformer system is controlled to switch from the compensation working mode to the non-compensation working mode by controlling the bypass device to switch the power electronic converter from the working compensation state to the non-working bypass state.

[0075] In a third aspect, the present invention provides a hybrid distribution transformer system, the system comprising an electromagnetic transformer, a power electronic converter, and a bypass device;

[0076] The bypass device is provided between the electromagnetic transformer and the power electronic converter, and is electrically connected to both the electromagnetic transformer and the power electronic converter;

[0077] The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter;

[0078] The control of the rectifier-stage converter is jointly implemented by the rectifier-stage PI controller and the rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve DC power output; the control of the inverter converter is jointly implemented by the inverter-stage PI controller and the inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve AC power output;

[0079] The hybrid distribution transformer system further includes a memory and a processor. The memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes the compensation switching method for the hybrid distribution transformer according to the first aspect.

[0080] By monitoring power quality parameters in real time, the present invention can dynamically switch between compensation and non-compensation of hybrid distribution transformers according to different power quality parameters, thereby optimizing power quality and reducing energy consumption. Specific beneficial effects are as follows:

[0081] 1. Dynamic Adaptive Optimization: This invention dynamically switches between compensation and non-compensation modes based on real-time changes in power quality parameters, ensuring the system always operates optimally. This approach significantly improves power quality, including voltage regulation and harmonic suppression, while also reducing reactive power losses and increasing energy efficiency.

[0082] 2. Comprehensive improvement in power quality: This invention uses precise dynamic compensation and regulation to effectively suppress voltage fluctuations, harmonic interference, and reactive power imbalance, thereby ensuring the stable operation of electrical equipment and improving the user's power experience, such as reducing equipment damage and lowering electricity bills.

[0083] 3. Energy Saving and Economical: This invention can flexibly adjust compensation strategies based on load demand, reducing unnecessary reactive power losses and overall energy consumption. It also optimizes equipment utilization, reduces investment and maintenance costs, and maximizes economic benefits throughout the system's lifecycle.

[0084] 4. High reliability and fast response: The present invention has the ability to quickly respond to sudden load changes or grid disturbances, enhance system stability by seamlessly switching compensation working modes, significantly reduce the risk of power outages, and improve the anti-interference ability and long-term reliability of the distribution network.

[0085] 5. Multi-technology integration and collaboration: This invention combines the advantages of electromagnetic transformers and power electronic converters to achieve the collaborative operation of traditional equipment and intelligent control, taking into account high power density and flexible regulation capabilities to adapt to complex and changing power distribution scenarios.

[0086] 6. Intelligence and flexibility: The present invention supports automatic identification of power quality parameters (such as voltage deviation and harmonic content) and switches operating modes without human intervention, ensuring that the system can operate efficiently under various conditions such as light load, heavy load and nonlinear load. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 Schematic diagram of a compensation switching method for a hybrid distribution transformer in an embodiment of the present invention;

[0088] Figure 2 1 is a topological diagram of a hybrid distribution transformer system in an embodiment of the present invention;

[0089] Figure 3 A control flow chart for switching from a non-compensation working mode to a compensation working mode in an embodiment of the present invention;

[0090] Figure 4 This is a control flow chart for switching from a compensation working mode to a non-compensation working mode in an embodiment of the present invention;

[0091] Figure 5 A schematic diagram of the three-phase output voltage of the hybrid distribution transformer in a simulation experiment waveform diagram when the non-compensation working mode is switched to the compensation working mode in an embodiment of the present invention;

[0092] Figure 6 Schematic diagram of DC bus voltage in a simulation experiment waveform diagram when switching from a non-compensated working mode to a compensated working mode in an embodiment of the present invention;

[0093] Figure 7 Schematic diagram of the output current of the inverter converter in the simulation experiment waveform diagram when the non-compensation working mode is switched to the compensation working mode in an embodiment of the present invention;

[0094] Figure 8 Schematic diagram of the current flowing through the bypass bidirectional thyristor in the waveform diagram of the simulation experiment when the non-compensation working mode is switched to the compensation working mode in an embodiment of the present invention;

[0095] Figure 9 Schematic diagram of the current flowing through the bypass load isolation switch in a simulation experiment waveform diagram when the non-compensation working mode is switched to the compensation working mode in an embodiment of the present invention;

[0096] Figure 10 A schematic diagram of the three-phase output voltage of the hybrid distribution transformer in a simulation experiment waveform diagram when the compensation working mode is switched to the non-compensation working mode in an embodiment of the present invention;

[0097] Figure 11 Schematic diagram of DC bus voltage in a simulation experiment waveform diagram when the compensation working mode switches to the non-compensation working mode in an embodiment of the present invention;

[0098] Figure 12 Schematic diagram of the output current of the inverter converter in the simulation experiment waveform diagram when the compensation working mode is switched to the non-compensation working mode in the embodiment of the present invention;

[0099] Figure 13 Schematic diagram of the current flowing through the bypass bidirectional thyristor in the waveform diagram of the simulation experiment when the compensation working mode is switched to the non-compensation working mode in the embodiment of the present invention;

[0100] Figure 14 Schematic diagram of the current flowing through the bypass load isolation switch in a simulation experiment waveform diagram when the compensation working mode is switched to the non-compensation working mode in an embodiment of the present invention;

[0101] Figure 15 Schematic diagram of a compensation switching device for a hybrid distribution transformer in an embodiment of the present invention.

[0102] Reference numerals: 101, first acquisition unit, 102, second acquisition unit; 103, mode confirmation unit, 104, control unit. DETAILED DESCRIPTION

[0103] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0104] It should be understood that the specific embodiments and drawings described herein are only used to explain the present invention rather than to limit the present invention.

[0105] It is understood that, in the absence of conflict, the various embodiments of the present invention and the various features in the embodiments may be combined with each other.

[0106] It can be understood that, for the convenience of description, the drawings of the present invention only show parts related to the present invention, while parts unrelated to the present invention are not shown in the drawings.

[0107] It can be understood that each unit and module involved in the embodiments of the present invention may correspond to only one physical structure, or may be composed of multiple physical structures, or multiple units and modules may be integrated into one physical structure.

[0108] It will be understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of the present invention may occur in an order different from that marked in the drawings.

[0109] It is understood that the flowcharts and block diagrams of the present invention illustrate the possible architectures, functions, and operations of the systems, devices, equipment, and methods according to various embodiments of the present invention. Each box in the flowchart or block diagram may represent a unit, module, program segment, or code, which contains executable instructions for implementing the specified functions. Moreover, each box or combination of boxes in the block diagram and flowchart may be implemented using a hardware-based system that implements the specified functions, or may be implemented using a combination of hardware and computer instructions.

[0110] It can be understood that the units and modules involved in the embodiments of the present invention can be implemented by software or hardware. For example, the units and modules can be located in a processor.

[0111] Example 1:

[0112] This embodiment provides a compensation switching method for a hybrid distribution transformer system. This method is applicable to a variety of application scenarios, including industrial power distribution systems, commercial buildings, renewable energy access, data centers, and public transportation. In these scenarios, the method can monitor load conditions in real time and dynamically adjust the compensation operating mode, ensuring stable power quality and improving system efficiency, thereby meeting stringent requirements for power stability and energy utilization.

[0113] like Figure 1 As shown, the method is applied to a hybrid distribution transformer system, the hybrid distribution transformer system includes an electromagnetic transformer and a power electronic converter, the electromagnetic transformer and the power electronic converter are electrically connected, and the method includes the following steps:

[0114] Step S1: Obtain the current working mode of the hybrid distribution transformer system; the current working mode of the hybrid distribution transformer system includes a compensation working mode and a non-compensation working mode; wherein the compensation working mode indicates that the electromagnetic transformer is in a working state and the power electronic converter is in a working compensation state; the non-compensation working mode indicates that the electromagnetic transformer is in a working state and the power electronic converter is in a non-working bypass state.

[0115] "Compensation working mode" means that in the power system, the electromagnetic transformer is in a normal and stable working state, mainly responsible for power transmission or distribution tasks, ensuring stable power transmission and good voltage stability. At the same time, the power electronic converters (such as active filters, passive compensators or other controllable power electronic devices) are in a "working compensation state", that is, they actively operate and adjust the reactive power, harmonics, voltage deviation and other indicators of the power grid. Through precise control, they improve power quality, alleviate harmonic pollution, reduce reactive power losses, and enhance the stability and efficiency of power supply. At this time, the electronic converter adjusts its own output according to the real-time monitoring data of the power grid, actively compensates for the adverse effects in the system, ensures that the overall power quality meets the preset standards, and the system operates smoothly.

[0116] In "non-compensated operating mode," the electromagnetic transformer continues to operate normally, maintaining its fundamental power transmission function and maintaining stable power transmission. Meanwhile, the power electronic converter is in "bypass" mode, meaning it performs no compensation or regulation functions and is instead bypassed or shut down. This mode places the electronic equipment in standby or off mode, with no active power compensation performed. System operation relies solely on traditional transformers for basic power transmission. This mode is typically selected when power quality meets standards, with no harmonics, voltage deviation, or reactive power demand, or to conserve energy.

[0117] In summary, these two modes reflect the system's state under different operating strategies: the compensation mode emphasizes active regulation and improvement of power quality, providing additional dynamic optimization for the system; the non-compensation mode, on the other hand, maintains basic stability without additional compensation, and is suitable for scenarios where the system requires no intervention or detects that power quality meets requirements. This flexible and controllable switching mechanism ensures that the grid can cope with complex and changing power conditions while also saving energy and reducing emissions when compensation is not required, thereby improving overall operational efficiency and reliability.

[0118] In the compensated operating mode, a power electronic converter is connected in series to the secondary side of the transformer to achieve voltage compensation, reactive power compensation, and imbalance control. In the uncompensated operating mode, the power electronic converter is bypassed to the secondary side of the transformer using bidirectional thyristors and load disconnect switches, allowing the transformer to be independently powered. Automatic switching between these two operating modes is required based on actual operating conditions. Controlling the thyristors (which are bidirectional) ensures rapid mode switching. Furthermore, the introduction of load disconnect switches reduces energy losses caused by the bypass circuit and enhances system stability. Proper control of the converter's start and stop times helps further minimize energy losses to the entire distribution transformer system.

[0119] In this embodiment, the non-compensated operating mode refers to an operating state in which no compensation is performed. To reduce the losses caused by this non-compensated operating mode and enhance system stability, the power electronic converter is placed in bypass mode in this mode. Therefore, the non-compensated operating mode in this embodiment can also be referred to as bypass mode. This design effectively reduces energy losses and ensures that the system maintains good operating performance and safety in this state.

[0120] Step S2: obtaining power quality parameters of the hybrid distribution transformer system in the current working mode, and determining the next working mode of the hybrid distribution transformer system according to the power quality parameters and the current working mode.

[0121] Power quality parameters include actual voltage, actual reactive power, and actual imbalance. These parameters provide important indicators of power system performance and operational status. Voltage reflects the stability and reliability of power supply, ensuring that electrical equipment operates within the appropriate voltage range. Reactive power relates to the efficient transfer of energy in the power system, and its optimization is crucial for improving energy efficiency. Unbalance indicates the degree of difference between phase currents; excessive imbalance can lead to equipment overload and damage. Comprehensive monitoring and analysis of these power quality parameters can effectively improve the overall reliability and operational efficiency of the power system.

[0122] As a specific implementation method, determining the next operating mode of the hybrid distribution transformer system according to the power quality parameters and the current operating mode specifically includes the following steps:

[0123] determining, based on the power quality parameters, whether a threshold value exceeds a range in a current operating mode of the hybrid distribution transformer system; and determining, based on whether the threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system, a next operating mode of the hybrid distribution transformer system;

[0124] Based on the power quality parameters, determine whether the hybrid distribution transformer system exceeds the threshold range in the current operating mode, including:

[0125] If the actual voltage value exceeds the target voltage threshold, or the actual reactive value exceeds the target reactive threshold, or the actual unbalance exceeds the target unbalance, it is determined that the hybrid distribution transformer system has a threshold exceeding range; or,

[0126] If the actual voltage value does not exceed the target voltage threshold, the actual reactive power value does not exceed the target reactive power threshold, and the actual unbalance does not exceed the target unbalance, it is determined that the hybrid distribution transformer system does not exceed the threshold range;

[0127] Determining a next operating mode of the hybrid distribution transformer system according to whether a threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system includes:

[0128] If the current working mode is the non-compensation working mode and the hybrid distribution transformer system has a threshold value exceeding the range, then determining that the next working mode of the hybrid distribution transformer system is the compensation working mode; or,

[0129] If the current working mode is the compensation working mode and the hybrid distribution transformer system does not exceed the threshold, the next working mode of the hybrid distribution transformer system is determined to be the non-compensation working mode.

[0130] Step S3: Control the hybrid distribution transformer system to operate in the next working mode.

[0131] As a specific implementation, controlling the hybrid distribution transformer system to operate in the next working mode specifically includes:

[0132] If the current working mode is the non-compensation working mode and the next working mode is the non-compensation working mode, the hybrid distribution transformer system is controlled to operate in the non-compensation working mode; or,

[0133] If the current working mode is the compensation working mode and the next working mode is the compensation working mode, the hybrid distribution transformer system is controlled to operate in the compensation working mode; or,

[0134] If the current working mode is the non-compensation working mode and the next working mode is the compensation working mode, the hybrid distribution transformer system is controlled to switch from the non-compensation working mode to the compensation working mode, and then the hybrid distribution transformer system is controlled to operate in the compensation working mode; or,

[0135] If the current working mode is the compensation working mode and the next working mode is the non-compensation working mode, the hybrid distribution transformer system is controlled to switch from the compensation working mode to the non-compensation working mode, and then the hybrid distribution transformer system is controlled to operate in the non-compensation working mode.

[0136] In this embodiment, the hybrid distribution transformer system further includes a bypass device, which is provided between the electromagnetic transformer and the power electronic converter and is electrically connected to both the electromagnetic transformer and the power electronic converter;

[0137] Controlling the hybrid distribution transformer system to switch from a non-compensated operating mode to a compensated operating mode is achieved by controlling the bypass device to switch the power electronic converter from a non-operating bypass state to an operating compensation state;

[0138] Controlling the hybrid distribution transformer system to switch from a compensation working mode to a non-compensation working mode is achieved by controlling a bypass device to switch a power electronic converter from a working compensation state to a non-working bypass state.

[0139] As a specific implementation method, the bypass device includes a load isolating switch and a thyristor; the load isolating switch and the thyristor are connected in parallel;

[0140] The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter;

[0141] The control of the rectifier-stage converter is jointly implemented by the rectifier-stage PI controller and the rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve DC power output; the control of the inverter converter is jointly implemented by the inverter-stage PI controller and the inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve AC power output;

[0142] Controlling the hybrid distribution transformer system to switch from a non-compensated operating mode to a compensated operating mode specifically includes the following steps:

[0143] Step A1: Detecting the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0144] If the compensation signal p2 = 1 and the compensation operation flag k2 = 0, then proceed to step A2; if the compensation signal p2 = 0, or the compensation operation flag k2 = 1, then re-detect the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0145] Step A2: Send an opening command to the load isolation switch in the closed state; and, control the rectifier stage PI controller to reset; and, control the rectifier stage PWM port to trigger; and, control the rectifier stage converter to work to stabilize the DC bus voltage to the reference voltage U dc ;

[0146] Step A3: Control the load isolation switch to operate in the first preset time period t_ on1 Open the switch to fully open the load isolating switch and allow the current to flow through the thyristor;

[0147] Step A4: controlling the thyristor not to trigger; and controlling the inverter-stage PI controller to reset; and controlling the inverter PWM port to trigger;

[0148] Step A5: Control the inverter converter to operate, and set the compensation operation flag k2 to 1, thereby switching from the non-compensation operation mode to the compensation operation mode.

[0149] As a specific implementation, the first preset time period t_ on1 , that is, the opening time t_ on1 Set to 0.5 to 3 seconds.

[0150] Set opening time t_ on1 The primary purpose of a time delay of 0.5 to 3 seconds is to ensure that the load disconnect switch fully opens and safely disconnects the circuit. This time delay helps avoid instantaneous overloads or sudden current changes during the switching process, effectively protecting equipment from damage and ensuring safe operation of the converter. Furthermore, an appropriate time delay can effectively reduce current instability through the thyristor, thereby enhancing system stability and reliability.

[0151] In this embodiment, the logic program of the control system will on1 The delay is set to 0.5 to 3 seconds. When switching modes, the control logic issues an opening command to the load disconnect switch based on this preset time delay. This can be achieved using a timer or timing program to precisely control the timing of the switch opening, ensuring that no abnormalities occur during the switching process and avoiding power supply interruptions.

[0152] Opening time t_ on1 The setting of is not only a critical operating parameter but also reflects the system's high emphasis on safety and reliability during mode switching. This time ensures that during power conversion and equipment switching, the system waits sufficiently for the switch to fully open, avoiding potential electrical shock and equipment damage. Furthermore, this time setting provides an optimal operating environment for subsequent thyristor triggering and inverter operation, ensuring smooth and efficient mode switching.

[0153] About delay t_ on1 The specific duration of the delay depends on the time required for the load isolation switch to open. In this embodiment, the delay time is selected between 0.5 and 3 seconds. This range can ensure that the switch is fully opened without being too long to affect the response speed of the system. Selecting this time duration can effectively balance the safety of the equipment and the dynamic response capability of the system, avoiding current shocks caused by too short a delay, while also reducing energy loss and efficiency reduction caused by too long a delay. Therefore, the selection of 0.5 to 3 seconds as the delay time is the result of comprehensive considerations and can ensure the safe and efficient operation of the system.

[0154] When performing specific compensation, considering the cost issues in actual engineering applications, the design capacity of the converter cannot meet all compensation requirements at the same time. Dynamic voltage compensation has the highest priority, followed by unbalanced compensation and then reactive power compensation.

[0155] As a specific implementation method, the bypass device includes a load isolating switch and a thyristor; the load isolating switch and the thyristor are connected in parallel;

[0156] The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter;

[0157] The control of the rectifier-stage converter is jointly implemented by the rectifier-stage PI controller and the rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve DC power output; the control of the inverter converter is jointly implemented by the inverter-stage PI controller and the inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve AC power output;

[0158] Controlling the hybrid distribution transformer system to switch from a compensation mode to a non-compensation mode includes the following steps:

[0159] Step B1: Detecting the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0160] If the compensation signal p2 = 0 and the compensation operation flag k2 = 1, then proceed to step A2; if the compensation signal p2 = 1, or the compensation operation flag k2 = 0, then re-detect the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system;

[0161] Step B2: issuing a closing instruction to the load disconnect switch in the open state; and issuing a thyristor triggering signal;

[0162] Step B3: Control the load isolation switch to operate in the second preset time period t_ off1 Internal conduction to make the load isolation switch fully turned on and allow current to flow through the thyristor;

[0163] Step B4: controlling the blocking trigger of the inverter PWM port;

[0164] Step B5: Control the inverter converter to operate in the third preset time period t_ off2 Stop working to stabilize the DC bus voltage to the reference voltage Udc ;

[0165] Step B6: Control the latch triggering of the PWM port of the rectifier stage;

[0166] Step B7: Control the rectifier stage converter to stop working, and set the compensation operation flag k2 to 0, thereby switching from the compensation working mode to the non-compensation working mode.

[0167] As a specific implementation, the second preset time period t_ off1 , that is, the first closing time t_ off1 Set to 0.5 to 1.5 microseconds.

[0168] First closing time t_ off1 The purpose of setting the timer to 0.5 to 1.5 microseconds is to ensure stable system operation and avoid voltage drops caused by sudden current changes during the switchover from compensated to non-compensated mode. During this switchover process, the closing of the load disconnect switch and the operation of the inverter must be precisely controlled to maintain the power quality of the distribution system and the stability of the equipment.

[0169] Specifically, when the system needs to switch operating modes, in order to prevent the inverter stage from causing a voltage drop in the open circuit state, the load isolation switch must be completely closed. If the PWM port of the inverter is immediately locked after the shutdown command is executed, it may cause voltage drop and current instability. Therefore, the delay t_ off1 The setting of t_ is crucial. This time delay mainly depends on the turn-on delay of the thyristor. In this embodiment, t_ off1 The delay is set to 0.5 to 1.5 microseconds. This delay ensures that after the load isolation switch is turned off, the current can flow smoothly through the thyristor and stably maintain the system voltage level when it is turned on.

[0170] In practice, a time range of 0.5 to 1.5 microseconds is chosen over longer or shorter times because a time that is too short may not fully guarantee the conduction of the thyristor, resulting in current failure and a subsequent instantaneous voltage drop. On the other hand, setting the time too long may delay the system's response, affecting the rapid switching capability of the power supply and the overall system efficiency. Therefore, a time range of 0.5 to 1.5 microseconds is an experimentally proven optimal choice, which fully guarantees the conduction stability of the thyristor and ensures a rapid response of the system to mode switching.

[0171] In summary, t_ off1The design is designed to effectively prevent voltage drops caused by inverter stage open circuits during switching. Combined with the thyristor conduction characteristics, this design ensures safer and more efficient system operation. This meticulous design reflects the system's rigorous pursuit of power quality and power supply stability, helping to improve the reliability of distribution transformer operation and the management efficiency of the entire power network.

[0172] As a specific implementation, the third preset time period t_ off2 , that is, the second closing time t_ off2 Set to 20 to 60 milliseconds.

[0173] Second closing time t_ off2 The timer is set to 20 to 60 milliseconds. Its main purpose is to ensure that the DC bus voltage remains stable when switching from compensation mode to non-compensation mode. The specific instructions are as follows:

[0174] When the system switches from compensated to non-compensated operating mode, the shutdown of the inverter stage will directly affect the voltage stability of the DC bus. If sufficient delay is not set, the DC bus voltage may fluctuate, which will affect the performance and safety of the entire system. To prevent this from happening, it is necessary to add a certain delay after the inverter stops working. This will provide enough time for the DC bus voltage to stabilize through the rectifier stage converter and eventually reach the reference voltage (also called the set voltage) U dc .

[0175] In actual operation, t_ off2 The duration of this adjustment generally depends on the adjustment time of the rectifier-stage DC bus voltage controller under no-load conditions. In this embodiment, the controller requires 20 to 60 milliseconds to stabilize the DC voltage. This time range is equivalent to 1 to 3 AC power cycles. This range is selected because in power systems, stable voltage output typically requires several cycles of adjustment to allow the system to adapt to the new operating conditions and ensure that voltage fluctuations do not occur.

[0176] The reason for choosing 20-60 milliseconds over other delays is that a delay that is too short may prevent the rectifier stage from effectively regulating the DC bus voltage, preventing the required stability level and potentially causing transient instability in the power supply. Conversely, setting a delay that is too long will reduce the system's response speed and affect the switching efficiency of the general power supply. A delay of 20-60 milliseconds meets the system's voltage stability requirements while maintaining the system's fast response capability, thereby ensuring smooth switching between different operating modes.

[0177] Figure 2Figure 1 is a topological diagram of the hybrid distribution transformer system of this embodiment. In the figure, the hybrid distribution transformer consists of a transformer and a power electronic converter. The power electronic converter is composed of VSC1 and VSC2. VSC1 is the inverter stage of the converter, and VSC2 is the rectifier stage of the converter. The bypass circuit consists of a bidirectional thyristor and a load isolation switch.

[0178] This embodiment provides a compensation switching method for a hybrid distribution transformer, which includes two switching modes, specifically a first mode and a second mode.

[0179] First mode: Switch from non-compensation working mode (bypass mode) to compensation working mode, such as Figure 3 As shown, it specifically includes the following steps:

[0180] (1) Detecting a signal that the distribution transformer requires a converter to be connected in series with the power supply circuit for compensation;

[0181] (2) triggering the load isolation disconnection signal and starting the rectifier stage converter;

[0182] (3) Delay t_ on1 Finally, the load isolation switch is completely disconnected, the triggering signal of the bidirectional thyristor stops, and the inverter-stage converter is started.

[0183] The second mode, switching from compensation mode to non-compensation mode (bypass mode) is as follows:

[0184] (1) Detecting a signal that the distribution transformer does not need a converter to be connected in series with the power supply circuit for compensation (i.e., a bypass signal);

[0185] (2) triggering the load isolation switch closing signal and the bidirectional thyristor conduction signal;

[0186] (3) Delay t_ off1 Then the bidirectional thyristor is fully turned on and the inverter stage converter stops working;

[0187] (4) Delay t_ off2 After that, the DC bus voltage stabilizes to the reference voltage U dc , stop the rectifier stage converter from working.

[0188] In this embodiment, the two switching modes are:

[0189] The first mode: according to Figure 3 As shown, the hybrid transformer, which originally supplies power to the secondary side T1 of the transformer (i.e., electromagnetic transformer) separately, disconnects the bypass circuit, starts the power electronic converter, and connects the converter in series to the T1 terminal for compensation.

[0190] Second mode: According to Figure 2As shown, the power electronic converter originally connected in series to the secondary side T1 of the transformer is short-circuited from the T1 end by turning on the bypass circuit, and the operation of the converter is stopped.

[0191] In this embodiment, step (1) in the first mode specifically includes the following: when the hybrid transformer is in the non-compensation working mode (bypass mode), the circuit state data detected by the voltage and current sensors on the converter are analyzed and compared. If one of the following situations occurs, it is determined that a compensation signal is detected.

[0192] 1. When the output phase voltage V2 exceeds the rated voltage of 230V (1±5%);

[0193] 2. When the three-phase voltage imbalance at the output end exceeds 2%;

[0194] 3. When the power factor at transformer T1 is less than 0.95.

[0195] In this embodiment, step (2) in the first mode specifically includes the following: Figure 3 This is a control flow chart for switching from a non-compensated operating mode (bypass mode) to a compensated operating mode as described in this embodiment. After detecting that the compensation signal P2 = 1, an open command is issued to the load isolation switch in the closed state, the rectifier stage controller is reset, the rectifier stage PWM port triggers the output, and the rectifier stage converter operates, so that the DC bus voltage is stabilized to the set value of 300V.

[0196] In this embodiment, step (3) in the first mode specifically includes the following: Figure 3 As shown, after issuing the command to disconnect the load isolation switch, a delay of t_ on1 , used to ensure that the load isolation switch is completely disconnected, t_ on1 The time when the load isolation switch completes the switching action, in this embodiment, t_ on1 Set to 0.5s. Delay t_ on1 After that, the thyristor trigger signal is turned off, and at the same time, the inverter controller is reset, the inverter PWM port triggers the output, the inverter converter works, and is connected in series to the secondary power supply circuit of the transformer for compensation.

[0197] In this embodiment, step (1) in the second mode specifically includes the following: when the hybrid transformer is in the compensation working mode, by analyzing and comparing the circuit status data, if the compensation situation in step (1) of the first mode does not occur, it is determined that the exit compensation signal is detected.

[0198] In this embodiment, step (2) in the second mode specifically includes the following: Figure 4This is a control flow chart for switching from the compensation working mode to the non-compensation working mode (bypass mode) described in this embodiment. After detecting that the compensation signal P2 = 0, a closing instruction is issued to the load isolation switch in the open state, and a thyristor trigger signal is sent.

[0199] In this embodiment, step (3) in the second mode specifically includes the following: Figure 4 As shown, after the command is issued, in order to prevent the discontinuous phenomenon at the output end of the distribution transformer, a delay of t_ off1 After the bidirectional thyristor is fully turned on, the inverter stage PWM port of the converter is locked and triggered, and the inverter stage converter stops working. The thyristor conduction delay is about 0.5 to 1.5 μs, which is less than a switching cycle (0.1 ms). Therefore, t_ off1 Selecting 0.1ms can ensure stable switching.

[0200] In this embodiment, step (4) in the second mode specifically includes the following: Figure 4 As shown, after the inverter-stage converter stops working, the delay t_ off2 Until the DC bus voltage stabilizes to the reference voltage U dc , stop the rectifier stage converter from working. When the inverter stage stops working, the DC bus voltage will increase. At this time, the DC bus voltage needs to be regulated by the rectifier stage. Usually, the rectifier controller will restore the DC voltage stability within 1 to 3 AC power cycles. In this embodiment, the rectifier stage controller restores the DC voltage stability within 1.5 AC power cycles, so t_ off2 Select 0.03s.

[0201] To describe this embodiment more clearly, Figures 5 to 14 The simulation results of this embodiment are given. The parameters used in this experiment are shown in Table 1.

[0202] Table 1:

[0203] parameter Value Distribution transformer primary side T voltage 10kV Distribution transformer secondary side T1 voltage 400V DC voltage 300V Load isolation switch action time 0.5s Three-phase thyristor conduction time 0.01ms Three-phase thyristor turn-off time 10ms Switching cycle 0.1ms

[0204] Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 The first mode is the simulation experiment waveform diagram of switching from the non-compensation working mode (bypass mode) to the compensation working mode. Figure 5 The simulation waveforms of the three-phase output voltage of the hybrid distribution transformer when the non-compensation mode switches to the compensation mode are shown; Figure 6 is the simulated waveform of the DC bus voltage; Figure 7 Shows the simulated waveform of the inverter output current; Figure 8 Schematic diagram of bypassing the bidirectional thyristor current;

[0205] Figure 9 Displays the simulated waveform of the bypass load isolation switch current. Before 0.2s, Figure 5 The phase voltage V2 (also represented by U2) at the output end is 184V, which meets the conditions for starting the compensation working mode. P2 is set to 1. After 0.2s, the load isolation disconnection signal is triggered, the rectifier stage converter is started, and the DC bus voltage rises to the set value of 300V. Figure 6 As shown; after 0.4s (t = 0.6s), the load isolating switch is electrically disconnected, and the current flowing through the load isolating switch is diverted to flow through the thyristor, as shown Figure 8 and Figure 9 As shown in the figure, at t = 0.7s, the inverter converter is started and the thyristor is stopped from being triggered. According to the thyristor turn-off characteristics, when the thyristor loses the trigger signal, it will not be turned off immediately. For the three-phase thyristor circuit, it will take half an AC cycle (0.01s) to turn off. At this moment, the inverter converter is in a short-circuit state, and its current iVSC1 exceeds the maximum compensation current by 25%, which meets the design requirements. Figure 7 When the thyristor is completely turned off, it enters the compensation working mode, and the phase voltage at the output end of the distribution transformer increases from 184V to the rated value of 230V. Figure 5 shown.

[0206] Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 The second mode is the simulation experiment waveform diagram when switching from the compensation working mode to the non-compensation working mode (bypass mode). Figure 10 Displays the three-phase output voltage of the hybrid transformer when the compensation mode changes to the non-compensation mode; Figure 11 is the DC bus voltage waveform; Figure 12 Indicates the inverter output current; Figure 13 is the bypass bidirectional thyristor current; Figure 14 Displays the bypass load isolation switch current. Before 0.2s, if Figure 10 The phase voltage V2 at the output end is 230V, and the compensation conditions are not met. P2 is set to 0. After 0.2s, a closing command is issued to the load disconnector in the open state, and a thyristor trigger signal is sent. After a delay of 0.1ms, the inverter stage converter stops working. Figure 12 and Figure 13 As shown in the figure, the current flowing through the converter now flows through the thyristor instead, and the converter is bypassed and stops working. After the inverter stage stops working, the DC bus voltage rises and is stabilized by the rectifier stage control within 1.5 AC cycles. The rectifier stage control is turned off and the DC voltage is always maintained at 300V. Figure 11As shown, it is worth noting that the DC bus voltage will slowly decrease over time until it drops to the rectifier stage uncontrolled rectifier voltage of 234V and then stops decreasing; after 0.4s (t = 0.6s), the load isolation switch is electrically turned on, and the current flowing through the thyristor is changed to flow through the load isolation switch, reducing the conduction loss of the bypass circuit, as shown in Figure 2. Figure 13 and Figure 14 As shown in Figure 2; before and after entering the non-compensated working mode (bypass mode), the phase voltage at the transformer output is stable and within the rated range, as shown in Figure 2. Figure 10 shown.

[0207] The above simulation experiment results show that the implemented scheme can quickly, smoothly and reliably realize the switching between the compensation working mode and the non-compensation working mode (bypass mode).

[0208] This embodiment proposes a compensation switching method for a hybrid distribution transformer, which is applicable to various scenarios such as industrial distribution systems, commercial buildings, renewable energy access, data centers and public transportation. The method dynamically adjusts the working mode to ensure power quality and system efficiency by real-time monitoring of power quality parameters such as voltage, reactive power value and imbalance. During the switching process, a delay mechanism is used to ensure the safe switching of the load isolation switch and the stability of the DC bus voltage, thereby avoiding current mutations and voltage drops. Simulation experimental results show that this method can quickly and smoothly realize switching between the compensation working mode and the non-compensation working mode (bypass mode), further improving the reliability and efficiency of the system.

[0209] Example 2:

[0210] like Figure 15 As shown, this embodiment provides a compensation switching device for a hybrid distribution transformer system. The hybrid distribution transformer system includes an electromagnetic transformer and a power electronic converter, which are electrically connected. The device includes:

[0211] The first acquisition unit 101 is configured to acquire a current operating mode of the hybrid distribution transformer system; the current operating mode of the hybrid distribution transformer system includes a compensation operating mode and a non-compensation operating mode;

[0212] The compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in working compensation state; the non-compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in non-working bypass state.

[0213] The second acquisition unit 102 is connected to the first acquisition unit 101 and is used to obtain power quality parameters of the hybrid distribution transformer system in the current working mode;

[0214] The mode determination unit 103 is connected to the second acquisition unit 102 and is used to determine the next operating mode of the hybrid distribution transformer system according to the power quality parameters and the current operating mode;

[0215] The control unit 104 is connected to the mode determination unit 103 and is used to control the hybrid distribution transformer system to operate in the next working mode.

[0216] As a specific implementation, the mode determination unit 103 includes:

[0217] A first determining module is connected to the second acquiring unit and is used to determine whether a threshold value exceeds a range in the hybrid distribution transformer system in a current operating mode according to the power quality parameter;

[0218] a second determining module, connected to the first determining module, for determining a next operating mode of the hybrid distribution transformer system according to whether a threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system;

[0219] The first determination module includes:

[0220] A first determining submodule is connected to the second acquiring unit and is configured to determine that a threshold value exceeds a range in the hybrid distribution transformer system when the actual voltage value exceeds a target voltage threshold, or the actual reactive power value exceeds a target reactive power threshold, or the actual unbalance exceeds a target unbalance;

[0221] a second determining submodule, connected to the second acquiring unit, for determining that there is no threshold exceeding range in the hybrid distribution transformer system when the actual voltage value does not exceed the target voltage threshold, the actual reactive power value does not exceed the target reactive power threshold, and the actual unbalance does not exceed the target unbalance;

[0222] The second determination submodule includes:

[0223] A third determining submodule, connected to the first determining submodule, is configured to determine that the next operating mode of the hybrid distribution transformer system is a compensation operating mode when the current operating mode is a non-compensation operating mode and a threshold value of the hybrid distribution transformer system exceeds a range;

[0224] The fourth determination submodule is connected to the second determination submodule and is used to determine that the next working mode of the hybrid distribution transformer system is the non-compensation working mode when the current working mode is the compensation working mode and there is no threshold exceeding the range in the hybrid distribution transformer system.

[0225] As a specific implementation, the control unit 104 includes:

[0226] a first control unit connected to the mode determination unit, configured to control the hybrid distribution transformer system to operate in the non-compensation working mode when the current working mode is the non-compensation working mode and the next working mode is the non-compensation working mode;

[0227] a second control unit connected to the mode determination unit, configured to control the hybrid distribution transformer system to operate in the compensation working mode when the current working mode is the compensation working mode and the next working mode is the compensation working mode;

[0228] a third control unit, connected to the mode determination unit, configured to control the hybrid distribution transformer system to switch from the non-compensation working mode to the compensation working mode when the current working mode is the non-compensation working mode and the next working mode is the compensation working mode, and then control the hybrid distribution transformer system to operate in the compensation working mode;

[0229] The fourth control unit is connected to the mode determination unit and is used to control the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode when the current working mode is the compensation working mode and the next working mode is the non-compensation working mode, and then control the hybrid distribution transformer system to operate in the non-compensation working mode.

[0230] As a specific embodiment, the hybrid distribution transformer system further includes a bypass device, which is provided between the electromagnetic transformer and the power electronic converter and is electrically connected to both the electromagnetic transformer and the power electronic converter;

[0231] The third control unit includes a first switching module, the first switching module is used to control the hybrid distribution transformer system to switch from a non-compensation working mode to a compensation working mode;

[0232] The hybrid distribution transformer system is controlled to switch from a non-compensation working mode to a compensation working mode by controlling a bypass device to switch the power electronic converter from a non-working bypass state to a working compensation state.

[0233] The fourth control unit includes a second switching module, and the second switching module is used to control the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode;

[0234] The hybrid distribution transformer system is controlled to switch from the compensation working mode to the non-compensation working mode by controlling the bypass device to switch the power electronic converter from the working compensation state to the non-working bypass state.

[0235] The device in this embodiment can execute the method in embodiment 1.

[0236] Example 3:

[0237] like Figure 2 As shown, this embodiment provides a hybrid distribution transformer system, which includes an electromagnetic transformer, a power electronic converter, and a bypass device;

[0238] The bypass device is provided between the electromagnetic transformer and the power electronic converter, and is electrically connected to both the electromagnetic transformer and the power electronic converter;

[0239] The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter;

[0240] The control of the rectifier-stage converter is jointly implemented by the rectifier-stage PI controller and the rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve DC power output; the control of the inverter converter is jointly implemented by the inverter-stage PI controller and the inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve AC power output;

[0241] The hybrid distribution transformer system further includes a memory and a processor. The memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes the compensation switching method for the hybrid distribution transformer according to embodiment 1.

[0242] illustrate, Figure 2 The split transformer shown in Figure 1 is a special type of electromagnetic transformer because it also works on the principle of electromagnetic induction.

[0243] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A compensation switching method for a hybrid distribution transformer system, characterized in that: The hybrid distribution transformer system includes an electromagnetic transformer and a power electronic converter, wherein the electromagnetic transformer and the power electronic converter are electrically connected. The method includes the following steps: Acquire a current operating mode of the hybrid distribution transformer system; the current operating mode of the hybrid distribution transformer system includes a compensation operating mode and a non-compensation operating mode; The compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in working compensation state; the non-compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in non-working bypass state. Acquiring power quality parameters of the hybrid distribution transformer system in a current operating mode, and determining a next operating mode of the hybrid distribution transformer system based on the power quality parameters and the current operating mode; The hybrid distribution transformer system is controlled to operate according to the next operating mode.

2. The compensation switching method of the hybrid distribution transformer system according to claim 1, characterized in that: The power quality parameters include actual voltage value, actual reactive value, and actual unbalance; The determining, according to the power quality parameter and the current operating mode, a next operating mode of the hybrid distribution transformer system specifically includes: determining, based on the power quality parameter, whether a threshold value of the hybrid distribution transformer system exceeds a range in the current operating mode; and determining, based on whether the threshold value of the hybrid distribution transformer system exceeds a range in the current operating mode, a next operating mode of the hybrid distribution transformer system; Determining, based on the power quality parameter, whether a threshold value of the hybrid distribution transformer system exceeds a range in the current operating mode specifically includes: If the actual voltage value exceeds the target voltage threshold, or the actual reactive value exceeds the target reactive threshold, or the actual unbalance exceeds the target unbalance, it is determined that the hybrid distribution transformer system has a threshold exceeding range in the current operating mode; or If the actual voltage value does not exceed the target voltage threshold, the actual reactive power value does not exceed the target reactive power threshold, and the actual unbalance does not exceed the target unbalance, it is determined that the hybrid distribution transformer system does not exceed the threshold range; The determining of the next operating mode of the hybrid distribution transformer system according to whether a threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system specifically includes: If the current working mode is a non-compensation working mode and a threshold value of the hybrid distribution transformer system exceeds a range in the current working mode, determining that the next working mode of the hybrid distribution transformer system is a compensation working mode; or If the current working mode is the compensation working mode and no threshold value exceeds the range in the hybrid distribution transformer system, it is determined that the next working mode of the hybrid distribution transformer system is the non-compensation working mode.

3. The compensation switching method of the hybrid distribution transformer system according to claim 1 or 2, characterized in that: The controlling the hybrid distribution transformer system to operate according to the next working mode specifically includes: If the current working mode is a non-compensation working mode and the next working mode is a non-compensation working mode, controlling the hybrid distribution transformer system to operate in the non-compensation working mode; or, If the current working mode is the compensation working mode and the next working mode is the compensation working mode, controlling the hybrid distribution transformer system to operate in the compensation working mode; or, If the current working mode is a non-compensation working mode and the next working mode is a compensation working mode, controlling the hybrid distribution transformer system to switch from the non-compensation working mode to the compensation working mode, and then controlling the hybrid distribution transformer system to operate in the compensation working mode; or If the current working mode is the compensation working mode and the next working mode is the non-compensation working mode, the hybrid distribution transformer system is controlled to switch from the compensation working mode to the non-compensation working mode, and then the hybrid distribution transformer system is controlled to operate in the non-compensation working mode.

4. The compensation switching method of the hybrid distribution transformer system according to claim 3, characterized in that: The hybrid distribution transformer system further includes a bypass device, which is provided between the electromagnetic transformer and the power electronic converter and is electrically connected to both the electromagnetic transformer and the power electronic converter; The control of switching the hybrid distribution transformer system from the non-compensation working mode to the compensation working mode is achieved by controlling the bypass device to switch the power electronic converter from the non-working bypass state to the working compensation state; The control of switching the hybrid distribution transformer system from the compensation working mode to the non-compensation working mode is achieved by controlling the bypass device to switch the power electronic converter from the working compensation state to the non-working bypass state.

5. The compensation switching method of the hybrid distribution transformer system according to claim 4, characterized in that: The bypass device includes a load isolating switch and a thyristor; the load isolating switch and the thyristor are connected in parallel; The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter; The control of the rectifier-stage converter is jointly implemented by a rectifier-stage PI controller and a rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve direct current output; the control of the inverter converter is jointly implemented by an inverter-stage PI controller and an inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve alternating current output; The controlling the hybrid distribution transformer system to switch from the non-compensation working mode to the compensation working mode specifically comprises the following steps: Step A1: detecting the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system; If the compensation signal p2=1 and the compensation operation flag k2=0, then proceed to step A2; if the compensation signal p2=0, or the compensation operation flag k2=1, then re-detect the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system; Step A2: Sending an opening instruction to the load isolation switch in the closed state; and controlling the PI controller of the rectifier stage to reset; and controlling the PWM port of the rectifier stage to trigger; and controlling the rectifier stage converter to work to stabilize the DC bus voltage to the reference voltage U dc ; Step A3: Control the load isolation switch to operate in a first preset time period t_ on1 Opening the load isolating switch to fully open and allowing current to flow through the thyristor; Step A4: controlling the thyristor not to be triggered; and controlling the inverter stage PI controller to be reset; and controlling the inverter PWM port to be triggered; Step A5: Control the inverter converter to operate, and set the compensation operation flag k2 to 1, thereby switching from the non-compensation operation mode to the compensation operation mode.

6. The compensation switching method of the hybrid distribution transformer system according to claim 4, characterized in that: The bypass device includes a load isolating switch and a thyristor; the load isolating switch and the thyristor are connected in parallel; The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter; The control of the rectifier-stage converter is jointly implemented by a rectifier-stage PI controller and a rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve direct current output; the control of the inverter converter is jointly implemented by an inverter-stage PI controller and an inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve alternating current output; The controlling the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode specifically comprises the following steps: Step B1: detecting the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system; If the compensation signal p2=0 and the compensation operation flag k2=1, then proceed to step A2; if the compensation signal p2=1, or the compensation operation flag k2=0, then re-detect the compensation signal p2 and the compensation operation flag k2 of the hybrid distribution transformer system; Step B2: issuing a closing instruction to the load isolation switch in the open state; and issuing the thyristor triggering signal; Step B3: Control the load isolation switch in the second preset time period t_ off1 Internal conduction to fully conduct the load isolation switch and allow current to flow through the thyristor; Step B4: controlling the locking trigger of the inverter PWM port; Step B5: Control the inverter converter to operate in a third preset time period t_ off2 Stop working to stabilize the DC bus voltage to the reference voltage U dc ; Step B6: controlling the locking trigger of the rectifier stage PWM port; Step B7: Control the rectifier stage converter to stop working, and set the compensation operation flag k2 to 0, thereby switching from the compensation working mode to the non-compensation working mode.

7. A compensation switching device for a hybrid distribution transformer system, characterized in that: The hybrid distribution transformer system includes an electromagnetic transformer and a power electronic converter, wherein the electromagnetic transformer and the power electronic converter are electrically connected. The device includes: A first acquiring unit is configured to acquire a current operating mode of the hybrid distribution transformer system; the current operating mode of the hybrid distribution transformer system includes a compensation operating mode and a non-compensation operating mode; The compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in working compensation state; the non-compensation working mode indicates that the electromagnetic transformer is in working state and the power electronic converter is in non-working bypass state. a second acquisition unit, connected to the first acquisition unit, configured to acquire power quality parameters of the hybrid distribution transformer system in a current working mode; a mode determination unit, connected to the second acquisition unit, configured to determine a next operating mode of the hybrid distribution transformer system according to the power quality parameter and the current operating mode; A control unit is connected to the mode determination unit and is used to control the hybrid distribution transformer system to operate according to the next working mode.

8. The compensation switching device of the hybrid distribution transformer system according to claim 7, characterized in that: The power quality parameters include actual voltage value, actual reactive value, and actual unbalance; The mode determination unit includes: a first determining module, connected to the second acquiring unit, for determining, based on the power quality parameter, whether a threshold value of the hybrid distribution transformer system exceeds a range in the current operating mode; a second determining module, connected to the first determining module, configured to determine a next operating mode of the hybrid distribution transformer system according to whether a threshold value exceeds a range in the current operating mode of the hybrid distribution transformer system; The first determining module includes: A first determining submodule, connected to the second acquiring unit, configured to determine that a threshold value exceeds a range in the hybrid distribution transformer system in the current operating mode when the actual voltage value exceeds a target voltage threshold, or the actual reactive power value exceeds a target reactive power threshold, or the actual unbalance exceeds a target unbalance; a second determining submodule, connected to the second acquiring unit, configured to determine that there is no threshold exceeding range in the hybrid distribution transformer system when the actual voltage value does not exceed the target voltage threshold, the actual reactive power value does not exceed the target reactive power threshold, and the actual unbalance does not exceed the target unbalance; The second determining submodule includes: a third determining submodule, connected to the first determining submodule, configured to determine that the next operating mode of the hybrid distribution transformer system is the compensation operating mode when the current operating mode is the non-compensation operating mode and a threshold value of the hybrid distribution transformer system exceeds a range in the current operating mode; The fourth determination submodule is connected to the second determination submodule and is used to determine that the next working mode of the hybrid distribution transformer system is a non-compensation working mode when the current working mode is a compensation working mode and there is no threshold exceeding the range of the hybrid distribution transformer system.

9. The compensation switching device of the hybrid distribution transformer system according to claim 7 or 8, characterized in that: The control unit comprises: a first control unit, connected to the mode determination unit, configured to control the hybrid distribution transformer system to operate in the non-compensation working mode when the current working mode is the non-compensation working mode and the next working mode is the non-compensation working mode; a second control unit, connected to the mode determination unit, configured to control the hybrid distribution transformer system to operate in the compensation working mode when the current working mode is the compensation working mode and the next working mode is the compensation working mode; a third control unit, connected to the mode determination unit, configured to control the hybrid distribution transformer system to switch from the non-compensation working mode to the compensation working mode when the current working mode is the non-compensation working mode and the next working mode is the compensation working mode, and then control the hybrid distribution transformer system to operate in the compensation working mode; a fourth control unit, connected to the mode determination unit, and configured to control the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode when the current working mode is the compensation working mode and the next working mode is the non-compensation working mode, and then control the hybrid distribution transformer system to operate in the non-compensation working mode.

10. The compensation switching device of the hybrid distribution transformer system according to claim 9, characterized in that: The hybrid distribution transformer system further includes a bypass device, which is provided between the electromagnetic transformer and the power electronic converter and is electrically connected to both the electromagnetic transformer and the power electronic converter; The third control unit includes a first switching module, and the first switching module is used to control the hybrid distribution transformer system to switch from a non-compensation working mode to a compensation working mode; Wherein, the controlling of the hybrid distribution transformer system to switch from the non-compensation working mode to the compensation working mode is achieved by controlling the bypass device to switch the power electronic converter from the non-working bypass state to the working compensation state; The fourth control unit includes a second switching module, and the second switching module is used to control the hybrid distribution transformer system to switch from the compensation working mode to the non-compensation working mode; The control of switching the hybrid distribution transformer system from the compensation working mode to the non-compensation working mode is achieved by controlling the bypass device to switch the power electronic converter from the working compensation state to the non-working bypass state.

11. A hybrid distribution transformer system, characterized in that: Including electromagnetic transformer, power electronic converter, and bypass device; The bypass device is provided between the electromagnetic transformer and the power electronic converter, and is electrically connected to both the electromagnetic transformer and the power electronic converter; The power electronic converter includes a rectifier-stage converter and an inverter converter, wherein the rectifier-stage converter and the inverter converter are electrically connected, and the output of the rectifier-stage converter is the input of the inverter converter; The control of the rectifier-stage converter is jointly implemented by a rectifier-stage PI controller and a rectifier-stage PWM port, wherein the rectifier-stage PI controller and the rectifier-stage PWM port are electrically connected, the rectifier-stage PI controller generates a rectifier regulation signal, and the rectifier-stage PWM port generates PWM pulses according to the rectifier regulation signal to achieve direct current output; the control of the inverter converter is jointly implemented by an inverter-stage PI controller and an inverter-stage PWM port, wherein the inverter-stage PI controller and the inverter-stage PWM port are electrically connected, the inverter-stage PI controller generates an inverter regulation signal, and the inverter-stage PWM port generates PWM pulses according to the inverter regulation signal to achieve alternating current output; The hybrid distribution transformer system further includes a memory and a processor, wherein a computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the compensation switching method of the hybrid distribution transformer according to any one of claims 1 to 6.

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