An integrated power electronics "voltage-power-quality" distribution network compensation system

Abstract

The present invention discloses an integrated power electronic "voltage-power-quality" distribution network compensation system, including a power supply line, a compensation unit, an energy storage routing interface unit, a DC bus unit and a control unit. The compensation unit integrates three reversible PWM converters into one by using power electronic integration technology, and can simultaneously realize triple compensation of power supply line voltage, power and quality. Compared with traditional peak-valley balance and power grid compensation technology, the setting of dual parallel converters makes its adjustment speed faster. In order to avoid the problem of compensation failure caused by self-drawing electricity from the power grid, the present invention uses energy storage equipment to provide an energy source for the compensation unit. The application of energy storage technology, on the one hand, provides an energy buffer channel for the access of new energy to the grid, and on the other hand, enables the power generated during the low-peak period of the power grid to be reused, which truly helps to realize the green, efficient and economical operation of the distribution network.

Description

Technical Field

[0001] The present invention belongs to a circuit device or system for power supply or distribution, and specifically relates to an integrated power electronic "voltage-electric energy-quality" distribution network compensation system. Background Art

[0002] Power quality is an important term to measure the quality of industrial, commercial and household electricity. The main power quality problems that cause power system disturbances include: voltage quality, current quality, power supply quality and power consumption quality. Since the parameters of system components (generators, transformers, lines, etc.) are not ideally linear or symmetrical, the load properties are different and change randomly, and due to the imperfect control means, operation, external interference and various faults, the ideal perfect sinusoidal wave power supply state does not exist in reality. As a result, various problems in power grid operation, electrical equipment and electricity consumption have arisen, prompting the study of power quality issues to become a hot topic. Improving power quality is of great significance for the safe and economical operation of power grids and electrical equipment. Traditional compensation technologies, such as on-load tap-changing transformers, mainly draw energy from the primary windings connected in parallel to the transmission line, and the secondary windings connected in series to the transmission line will output compensation voltages in phase (0°) or in phase (180°) with the line voltage, but they have the problem of self-drawing electricity aggravating voltage drops; static synchronous series compensators (SSSCs) mainly compensate for reactive power for current quality problems, but do not have the functions of active power compensation, harmonic compensation, and three-phase unbalanced compensation; unified power flow controllers (UPFCs) combine the advantages of static synchronous compensators (STATCOMs) and static synchronous series compensators (SSSCs) and can adjust the active power flow of lines in real time. However, UPFCs still have the defect of self-drawing electricity, which will aggravate voltage drops when large-capacity compensation is required.

[0003] Therefore, in the modern electrical society with increasing electricity demand and higher requirements for power quality, this field urgently needs a multifunctional power compensation substation with greater freedom to obtain a multi-objective control that takes into account economic benefits, equipment reliability, and power quality, and thus provide a reference for the coordinated operation of AC transmission networks and emerging power electronic equipment. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide an integrated power electronic "voltage-power-quality" distribution network compensation system, and to simultaneously realize triple compensation of voltage, power and quality of the distribution network power supply line. Compared with traditional peak-valley balance and power grid compensation technology, the present invention has many advantages such as higher integration, larger capacity, and faster adjustment speed. The configuration of dual parallel converters makes the adjustment response speed more timely. The use of energy storage technology not only provides an energy buffering channel for the access of new energy to the grid, but also enables the power generated during the off-peak period of the power grid to be fully utilized during the peak period, which truly helps to realize the green, efficient and economical operation of the distribution network.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] An integrated power electronic "voltage-power-quality" distribution network compensation system includes a power supply line, a compensation unit is connected between the input and output ends of the power supply line, the compensation unit is connected to an energy storage routing interface unit through a DC bus unit, and the input end of the power supply line is connected to the compensation unit and the energy storage routing interface unit via a control unit.

[0007] Preferably, the input end of the compensation unit is connected to the input end of the power supply line, and the output end is connected to the output end of the power supply line, the input end of the power supply line includes a three-phase line input end and a neutral line input end, and the output end of the power supply line includes a three-phase line output end and a neutral line output end, and the compensation unit is used to simultaneously realize voltage compensation, electric energy compensation and quality compensation of the distribution network; and realize power compensation at the same time;

[0008] The energy storage routing interface unit is connected to the compensation unit through the DC bus unit, and is used to provide an energy source for the compensation unit or store the grid energy absorbed by the compensation unit, and provide an Internet access interface for new energy and energy storage equipment;

[0009] The DC bus unit is used to realize the energy flow inside the system;

[0010] The control unit is connected to the compensation unit and the energy storage routing interface unit, and is used to control the compensation unit and the energy storage routing interface unit to complete corresponding power conversion to achieve triple compensation of voltage, electric energy and quality.

[0011] Preferably, the compensation unit comprises: an integrated compensation module, a first transformer, a second transformer, and a third transformer, wherein:

[0012] The integrated compensation module adopts three three-phase voltage-type reversible PWM converters (VSRs) connected in a "back-to-back-to-back" form, that is, the DC side of the first voltage-type reversible PWM converter is connected to the DC side of the second voltage-type reversible PWM converter through a first capacitor, and the DC side of the second voltage-type reversible PWM converter is connected to the DC side of the third voltage-type reversible PWM converter through a second capacitor. The common DC side of the three three-phase voltage-type reversible PWM converters (VSRs) leads to a DC bus terminal connected to the DC bus unit. The integrated compensation module is used to perform power conversion according to the control signal of the control unit to achieve the triple compensation of distribution network voltage, electric energy and quality;

[0013] The primary winding of the first transformer is connected to the AC side of the first voltage-type reversible PWM converter, and the secondary winding is connected in parallel to the three-phase four-wire distribution network power supply line, that is, connected in parallel between the three-phase phase line and the neutral line. The first transformer is used to realize energy interaction between the first voltage-type reversible PWM converter and the distribution network power supply line, and realize power compensation or quality compensation of the distribution network, that is, injecting the compensation current generated by the first voltage-type reversible PWM converter into the distribution network power supply line or absorbing the distribution network current;

[0014] The primary winding of the second transformer is connected to the AC side of the second voltage-type reversible PWM converter, and the secondary winding is connected in series to the power supply line of the distribution network, so as to couple the compensation voltage generated by the second voltage-type reversible PWM converter to the power supply line of the distribution network to achieve corresponding voltage compensation;

[0015] The primary winding of the third transformer is connected to the AC side of the third voltage-type reversible PWM converter, and the secondary winding is connected in parallel to the distribution network power supply line. The third transformer is used to realize energy interaction between the third voltage-type reversible PWM converter and the distribution network power supply line, and realize power compensation or quality compensation of the distribution network, that is, injecting the compensation current generated by the third voltage-type reversible PWM converter into the distribution network power supply line or absorbing the distribution network current.

[0016] Preferably, the energy storage routing interface unit comprises: a wind power interface converter, a photovoltaic interface converter, an energy storage device, and a router bus module, wherein:

[0017] The wind power interface converter adopts an AC / DC converter topology, with the DC side connected to the router bus module and the AC side connected to the wind power access terminal, and is used to access the AC power generated by wind power generation and convert it into controllable DC power;

[0018] The photovoltaic interface converter adopts a DC / DC converter topology, one end of the DC side is connected to the router bus module, and the other end is connected to the photovoltaic access terminal, which is used to access the DC power generated by photovoltaic power generation and convert it into controllable DC power;

[0019] The DC side of the energy storage device is connected to the router bus module, and the peak and valley regulation of the distribution network load and the energy buffering of the new energy grid are achieved by alternating charging and discharging;

[0020] The router bus module is connected to the DC bus unit, and is used to realize the energy flow inside the energy storage routing interface unit, and realize the bidirectional energy flow between the energy storage routing interface unit and the compensation unit through the DC bus unit.

[0021] Preferably, the control unit comprises: a power grid information sensing detection module and a compensation unit control module and an energy storage routing interface unit control module connected thereto, wherein:

[0022] The power grid information sensing detection module is used to obtain the three-phase voltage and current information of the power distribution network power supply line, and output it to the compensation unit control module and the energy storage routing interface unit control module;

[0023] The output end of the compensation unit control module is connected to the compensation unit, and is used to control the integrated compensation module in the compensation unit to complete the corresponding power conversion according to the three-phase voltage and current information, so as to realize triple compensation of voltage, energy and quality;

[0024] The output end of the energy storage routing interface unit control module is connected to the energy storage routing interface unit, and is used to control each power converter of the energy storage routing interface unit to complete the corresponding power change according to the three-phase voltage and current information, thereby providing the compensation unit with the energy source required for compensation, or storing the electric energy absorbed by the compensation unit, and realizing energy buffering control of new energy grid access.

[0025] Preferably, the energy interaction mode between the first voltage-type reversible PWM converter and the distribution network power supply line includes: power quality compensation mode and power (power) compensation mode, wherein the power quality compensation mode is used to inject compensation current into the power grid to achieve reactive power, harmonic and three-phase imbalance compensation of the distribution network power supply line; the power (power) compensation mode is used to inject current into the power grid or absorb power grid current to achieve load peak and valley regulation of the distribution network line.

[0026] Preferably, the energy interaction mode between the third voltage-type reversible PWM converter and the distribution network power supply line includes: power quality compensation mode and power (power) compensation mode, wherein the power quality compensation mode is used to inject compensation current into the power grid to achieve reactive power, harmonic and three-phase imbalance compensation of the distribution network power supply line; the power (power) compensation mode is used to inject current into the power grid or absorb power grid current to achieve load peak and valley regulation of the distribution network line.

[0027] Compared with the prior art, the integrated power electronic "voltage-power-quality" distribution network compensation system of the present invention has the following outstanding substantive features and significant progress:

[0028] (1) The integrated power electronic "voltage-power-quality" distribution network compensation system of the present invention overcomes the problem of single compensation function of existing power grid compensation equipment, and realizes comprehensive compensation of voltage, power (power), and quality. Each compensation can operate independently or in a coordinated manner to form a coordinated compensation system, which improves the fault tolerance capability of the device.

[0029] (2) The energy storage routing interface unit in the integrated power electronic "voltage-power-quality" distribution network compensation system of the present invention has a wide range of energy sources, including: power grid and new energy sources such as photovoltaic and wind power, so that the energy configuration of the system is flexible and does not rely on a single energy source. Multiple energies together form a complementary system. In addition, the addition of energy storage modules, used in conjunction with compensation units, can effectively solve the situation where energy demand changes drastically due to load fluctuations, climate fluctuations, day and night changes, etc., and the inability to compensate due to unstable energy sources;

[0030] (3) The integrated power electronics "voltage-power-quality" distribution network compensation system of the present invention uses integrated power electronics technology to integrate three reversible PWM converters into one module, which can simultaneously achieve triple compensation of voltage, power and quality. Through the setting of two parallel converters, the active power absorption speed is faster during the load valley period. The two converters can absorb active power at the same time, so active power can be released at the same time during the load valley period, which greatly improves the response speed and control accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic diagram of the structure of an integrated power electronic "voltage-power-quality" distribution network compensation system.

[0032] Figure 2 It is a schematic diagram of the compensation unit structure of the present invention.

[0033] Figure 3 It is a topological schematic diagram of a three-phase voltage-type reversible PWM converter in the integrated compensation module of the present invention.

[0034] Figure 4 It is a schematic diagram of the structure of the energy storage routing interface unit of the present invention.

[0035] Figure 5 It is a schematic diagram of the structure of a control unit of the present invention. DETAILED DESCRIPTION

[0036] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and preferred embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0037] Embodiment 1:

[0038] See also Figure 1 to Figure 5 An integrated power electronic "voltage-power-quality" distribution network compensation system includes a power supply line, a compensation unit 1 is connected between the input and output ends of the power supply line, the compensation unit 1 is connected to an energy storage routing interface unit 2 through a DC bus unit 3, and the input end of the power supply line is connected to the compensation unit 1 and the energy storage routing interface unit 2 via a control unit 4.

[0039] Embodiment 2:

[0040] This embodiment is basically the same as the first embodiment, with the following special features:

[0041] The input end of the compensation unit 1 is connected to the input end of the power supply line, and the output end is connected to the output end of the power supply line. The input end of the power supply line includes: a three-phase line input end and a neutral line input end, and the output end of the power supply line includes: a three-phase line output end and a neutral line output end. The compensation unit 1 is used to simultaneously realize voltage compensation, electric energy (power) compensation and quality compensation of the distribution network;

[0042] The energy storage routing interface unit 2 is connected to the compensation unit 1 through the DC bus unit 3, and is used to provide an energy source for the compensation unit 1 or store the grid energy absorbed by the compensation unit 1, and provide an Internet access interface for new energy and energy storage equipment;

[0043] The DC bus unit 3 is used to realize the energy flow inside the system;

[0044] The control unit 4 is connected to the compensation unit 1 and the energy storage routing interface unit 2, and is used to control the compensation unit 1 and the energy storage routing interface unit 2 to complete corresponding power conversion to achieve triple compensation of voltage, electric energy and quality.

[0045] Embodiment three:

[0046] like Figure 1 As shown, an integrated power electronic "voltage-power-quality" distribution network compensation system includes a compensation unit 1, an energy storage routing interface unit 2, a DC bus unit 3, and a control unit 4; the input end of the compensation unit 1 is connected to the power supply line input end including a three-phase phase line input end and a neutral line input end, and the output end is connected to the power supply line output end including: a three-phase phase line output end and a neutral line output end, and the compensation unit 1 is used to simultaneously realize distribution network voltage compensation, power compensation and quality compensation; the energy storage routing interface unit 2 is connected to the compensation unit 1 through the DC bus unit 3, and is used to provide an energy source for the compensation unit 1 or store the grid energy absorbed by the compensation unit 1, and at the same time provide an Internet access interface for new energy and energy storage equipment; the DC bus unit 3 is used to realize the energy flow within the system; the control unit 4 is connected to the compensation unit 1 and the energy storage routing interface unit 2, and is used to control the compensation unit 1 and the energy storage routing interface unit 2 to complete the corresponding power conversion to realize the triple compensation of voltage, power and quality.

[0047] Among them, Figure 2 As shown, the compensation unit 1 includes: an integrated compensation module 11, a first transformer 12, a second transformer 13, and a third transformer 14. The integrated compensation module 11 adopts three Figure 3 The three-phase voltage-type reversible PWM converters (VSRs) shown are connected in a "back-to-back-to-back" form, that is, the DC side of the first voltage-type reversible PWM converter 111 is connected to the DC side of the second voltage-type reversible PWM converter 112 through a first capacitor, and the DC side of the second voltage-type reversible PWM converter 112 is connected to the DC side of the third voltage-type reversible PWM converter 113 through a second capacitor. The common DC side of the three three-phase voltage-type reversible PWM converters (VSRs) leads to a DC bus terminal connected to a DC bus unit 3, and an integrated compensation module is used to perform power conversion according to a control signal of the control unit 4 to achieve triple compensation of voltage, electric energy and quality;

[0048] The primary winding of the first transformer 12 is connected to the AC side of the first voltage-type reversible PWM converter 111, and the secondary winding is connected in parallel to the three-phase four-wire power distribution network line, that is, connected in parallel between the three-phase phase line and the neutral line. The first transformer 12 is used to realize the energy interaction between the first voltage-type reversible PWM converter 111 and the power distribution network line, and realize the power compensation or quality compensation of the distribution network, that is, to inject the compensation current generated by the first voltage-type reversible PWM converter 111 into the power distribution network line or absorb the grid current;

[0049] The primary winding of the second transformer 13 is connected to the AC side of the second voltage-type reversible PWM converter 112, and the secondary winding is connected in series to the power supply line of the distribution network, so as to couple the compensation voltage generated by the second voltage-type reversible PWM converter to the power supply line of the distribution network to achieve corresponding voltage compensation;

[0050] The primary winding of the third transformer 14 is connected to the AC side of the third voltage-type reversible PWM converter 113, and the secondary winding is connected in parallel to the distribution network power supply line. The third transformer 14 is used to realize energy interaction between the third voltage-type reversible PWM converter 113 and the distribution network power supply line, and realize power compensation or quality compensation of the distribution network, that is, injecting the compensation current generated by the third voltage-type reversible PWM converter 113 into the distribution network power supply line or absorbing the distribution network current.

[0051] Among them, Figure 4 As shown, the energy storage routing interface unit includes: a wind power interface converter 21, a photovoltaic interface converter 22, an energy storage device 23, and a router bus module 24. The wind power interface converter 21 adopts an AC / DC converter topology, the DC side is connected to the router bus module 24, and the AC side is connected to the wind power access terminal, for accessing the AC power generated by wind power generation and converting it into controllable DC power; the photovoltaic interface converter 22 adopts a DC / DC converter topology, one end of the DC side is connected to the router bus module 24, and the other end is connected to the photovoltaic access terminal, for accessing the DC power generated by photovoltaic power generation and converting it into controllable DC power; the DC side of the energy storage device 23 is connected to the router bus module 24, and the peak-valley regulation of the distribution network line load and the energy buffering of the new energy grid are realized by alternating charging and discharging. The router bus module 24 is connected to the DC bus unit 3, for realizing the energy flow inside the energy storage routing interface unit 2, and realizing the bidirectional energy flow between the energy storage routing interface unit 2 and the compensation unit 1 through the DC bus unit 3.

[0052] Among them, Figure 5 As shown, the control unit 4 includes: a power grid information sensing detection module 43 and a compensation unit control module 41 and an energy storage routing interface unit control module 42 connected thereto, wherein the power grid information sensing detection module 43 is used to obtain the three-phase voltage and current information of the distribution network power supply line, and output it to the compensation unit control module 41 and the energy storage routing interface unit control module 42, the output end of the compensation unit control module 41 is connected to the compensation unit 1, and is used to control the integrated compensation module 11 in the compensation unit 1 according to the voltage and current information of the three-phase power supply line to complete the corresponding power conversion of the three voltage-type reversible PWM converters, thereby realizing the triple compensation of voltage, energy and quality; the output end of the energy storage routing interface unit control module 42 is connected to the energy storage routing interface unit 2, and is used to control the various power converters of the energy storage routing interface unit 2 according to the voltage and current information of the three-phase power supply line to complete the corresponding power change, thereby providing the compensation unit 1 with the energy source required for compensation, or storing the electric energy absorbed by the compensation unit 1, and realizing the energy buffer control of the new energy grid access.

[0053] The energy interaction mode between the first voltage-type reversible PWM converter 111 and the power distribution network power supply line includes at least one of the following two modes: power quality compensation mode and power (power) compensation mode. In the power quality compensation mode, the first voltage-type reversible PWM converter 111 injects compensation current into the power grid. At this time, the first voltage-type reversible PWM converter 111 works in the inverter state, which is used to realize reactive power, harmonics, and three-phase unbalance compensation of the power distribution network power supply line; in the power compensation mode, the first voltage-type reversible PWM converter 111 injects current into the power grid or absorbs the power grid current. At this time, the first voltage-type reversible PWM converter 111 works in the inverter state or the rectifier state depending on the power grid load. When the power grid load is in the peak period, the first voltage-type reversible PWM converter 111 works in the inverter state to provide power to the power grid. When the power grid load is in the valley period, the first voltage-type reversible PWM converter 111 works in the rectifier state to absorb the excess power of the power grid, thereby realizing the peak-valley regulation of the load of the distribution network line.

[0054] The energy interaction mode between the third voltage-type reversible PWM converter 113 and the distribution network power supply line includes at least one of the following two modes: power quality compensation mode and power (power) compensation mode. In the power quality compensation mode, the third voltage-type reversible PWM converter 113 injects compensation current into the power grid. At this time, the third voltage-type reversible PWM converter 113 works in the inverter state, which is used to realize reactive power, harmonics, and three-phase unbalance compensation of the distribution network power supply line; in the power compensation mode, the third voltage-type reversible PWM converter 113 injects current into the power grid or absorbs the power grid current. At this time, the third voltage-type reversible PWM converter 113 works in the inverter state or the rectifier state depending on the load of the power grid. When the load of the power grid is in the peak period, the third voltage-type reversible PWM converter 113 works in the inverter state to provide power to the power grid. When the load of the power grid is in the valley period, the third voltage-type reversible PWM converter 113 works in the rectifier state to absorb the excess power of the power grid, thereby realizing the peak-valley regulation of the load of the distribution network line.

[0055] The combination of the working modes of the first voltage-type reversible PWM converter 111 and the third voltage-type reversible PWM converter 113 can meet different distribution network compensation requirements. When the voltage does not drop and only load adjustment is required, the two reversible PWM converters can work in the rectification state at the same time, and their active power absorption rate is twice that of a single parallel converter, so their adjustment speed is also twice that of a single parallel converter. When a slight voltage drop occurs, the first voltage-type reversible PWM converter or the third voltage-type reversible PWM converter can work in the rectification state to provide a compensation energy source for the compensation unit. At this time, the energy source is the power grid, and the energy in the energy storage device is not consumed. During the peak load period, when a serious voltage drop occurs, the first voltage-type reversible PWM converter or the third voltage-type reversible PWM converter can work in the inversion state to inject current into the power grid, and can also be used to achieve reactive power, harmonics and three-phase unbalance compensation. The present invention utilizes energy storage equipment to provide an energy source for the compensation unit. The application of energy storage technology, on the one hand, provides an energy buffer channel for the access of new energy to the grid, and on the other hand, enables the electric energy generated during the off-peak period of the power grid to be reused, which truly helps to realize the green and efficient operation of the distribution network.

[0056] Based on the above embodiments, it can be known that the integrated power electronic "voltage-power-quality" distribution network compensation system of the present invention includes a power supply line, a compensation unit, an energy storage routing interface unit, a DC bus unit and a control unit. The compensation unit integrates three reversible PWM converters into one by using power electronic integration technology, and can simultaneously realize triple compensation of power supply line voltage, power and quality. Compared with traditional peak-valley balance and power grid compensation technology, the setting of dual parallel converters makes its adjustment speed faster. In order to avoid the problem of compensation failure caused by self-drawing electricity from the power grid, the present invention uses energy storage equipment to provide an energy source for the compensation unit. The application of energy storage technology, on the one hand, provides an energy buffer channel for the access of new energy to the grid, and on the other hand, enables the power generated during the low-peak period of the power grid to be reused, which truly helps to realize the green and efficient operation of the distribution network.

[0057] It can be seen that the purpose of the present invention has been completely and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments. Without departing from the principles, the implementation methods can be modified arbitrarily. The present invention includes all modified implementation methods based on the spirit and scope of the claims.

Claims

1. An integrated power electronic "voltage-power-quality" distribution network compensation system, including a power supply line, characterized in that: A compensation unit (1) is connected between the input and output ends of the power supply line; the compensation unit (1) is connected to an energy storage routing interface unit (2) via a DC bus unit (3); the input end of the power supply line is connected to the compensation unit (1) and the energy storage routing interface unit (2) via a control unit (4); the compensation unit (1) comprises: an integrated compensation module (11), a first transformer (12), a second transformer (13), and a third transformer (14), wherein: The integrated compensation module (11) uses three three-phase voltage-type reversible PWM converters (VSRs) connected in a "back-to-back-to-back" manner, that is, the DC side of the first voltage-type reversible PWM converter (111) is connected to the DC side of the second voltage-type reversible PWM converter (112) via a first capacitor, and the DC side of the second voltage-type reversible PWM converter (112) is connected to the DC side of the third voltage-type reversible PWM converter (113) via a second capacitor. The common DC side of the three three-phase voltage-type reversible PWM converters (VSRs) lead out a DC bus terminal connected to the DC bus unit (3). The integrated compensation module is used to perform power conversion according to the control signal of the control unit (4) to achieve the triple compensation of distribution network voltage, electric energy and quality; The primary winding of the first transformer (12) is connected to the AC side of the first voltage-type reversible PWM converter (111), and the secondary winding is connected in parallel to a three-phase four-wire power distribution network line, that is, connected in parallel between the three-phase phase line and the neutral line. The first transformer is used to realize energy interaction between the first voltage-type reversible PWM converter (111) and the power distribution network line, and realize power compensation or quality compensation of the distribution network, that is, injecting the compensation current generated by the first voltage-type reversible PWM converter (111) into the power distribution network line or absorbing the current of the distribution network; The primary winding of the second transformer (13) is connected to the AC side of the second voltage-type reversible PWM converter (112), and the secondary winding is connected in series to the power supply line of the distribution network, so as to couple the compensation voltage generated by the second voltage-type reversible PWM converter to the power supply line of the distribution network, thereby realizing corresponding voltage compensation; The primary winding of the third transformer (14) is connected to the AC side of the third voltage-type reversible PWM converter (113), and the secondary winding is connected in parallel to the distribution network power supply line. The third transformer (14) is used to realize energy interaction between the third voltage-type reversible PWM converter (113) and the distribution network power supply line, and realize power compensation or quality compensation of the distribution network, that is, injecting the compensation current generated by the third voltage-type reversible PWM converter (113) into the distribution network power supply line or absorbing the distribution network current.

2. The integrated power electronic "voltage-power-quality" distribution network compensation system according to claim 1 is characterized in that: The input end of the compensation unit (1) is connected to the input end of the power supply line, and the output end is connected to the output end of the power supply line, the input end of the power supply line includes: a three-phase line input end and a neutral line input end, the output end of the power supply line includes: a three-phase line output end and a neutral line output end, the compensation unit (1) is used to simultaneously realize voltage compensation, electric energy compensation and quality compensation of the distribution network; The energy storage routing interface unit (2) is connected to the compensation unit (1) via the DC bus unit (3) and is used to provide an energy source for the compensation unit (1) or to store grid energy absorbed by the compensation unit (1), while providing an Internet access interface for new energy and energy storage equipment; The DC bus unit (3) is used to realize energy flow within the system; The control unit (4) is connected to the compensation unit (1) and the energy storage routing interface unit (2) and is used to control the compensation unit (1) and the energy storage routing interface unit (2) to complete corresponding power conversion to achieve triple compensation of voltage, electric energy and quality.

3. The integrated power electronic "voltage-power-quality" distribution network compensation system according to claim 1 is characterized in that: The energy storage routing interface unit (2) comprises: a wind power interface converter (21), a photovoltaic interface converter (22), an energy storage device (23), and a router bus module (24), wherein: The wind power interface converter (21) adopts an AC / DC converter topology, the DC side is connected to the router bus module (24), and the AC side is connected to the wind power access terminal, and is used to access the AC power generated by wind power generation and convert it into controllable DC power; The photovoltaic interface converter (22) adopts a DC / DC converter topology, one end of the DC side is connected to the router bus module (24), and the other end is connected to the photovoltaic access terminal, and is used to access the DC power generated by photovoltaic power generation and convert it into controllable DC power; The DC side of the energy storage device (23) is connected to the router bus module (24), and the peak-valley regulation of the distribution network line load and the energy buffering of the new energy grid are achieved by alternating charging and discharging; The router bus module (24) is connected to the DC bus unit (3) and is used to realize energy flow inside the energy storage routing interface unit (2), and realize bidirectional energy flow between the energy storage routing interface unit (2) and the compensation unit (1) through the DC bus unit (3).

4. The integrated power electronic "voltage-power-quality" distribution network compensation system according to claim 1 is characterized in that: The control unit (4) comprises: a power grid information sensing detection module (43), a compensation unit control module (41) and an energy storage routing interface unit control module (42) connected thereto, wherein: The power grid information sensing detection module (43) is used to obtain three-phase voltage and current information of the power supply line of the distribution network, and output it to the compensation unit control module (41) and the energy storage routing interface unit control module (42); The output end of the compensation unit control module (41) is connected to the compensation unit (1) and is used to control the integrated compensation module (11) in the compensation unit (1) to complete corresponding power conversion according to the three-phase voltage and current information, thereby realizing triple compensation of voltage, energy and quality; The output end (42) of the energy storage routing interface unit control module is connected to the energy storage routing interface unit (2) and is used to control the various power converters of the energy storage routing interface unit (2) to complete corresponding power changes according to the three-phase voltage and current information, thereby providing the compensation unit (1) with a source of energy required for compensation, or storing the electric energy absorbed by the compensation unit (1), while realizing energy buffering control for new energy grid access.

5. The integrated power electronic "voltage-power-quality" distribution network compensation system according to claim 1 is characterized in that: The energy interaction modes between the first voltage-type reversible PWM converter (111) and the distribution network power supply line include: a power quality compensation mode and a power compensation mode, wherein the power quality compensation mode is used to inject compensation current into the power grid to achieve reactive power, harmonic and three-phase imbalance compensation of the distribution network power supply line; the power compensation mode is used to inject current into the power grid or absorb power grid current to achieve load peak and valley regulation of the distribution network line.

6. The integrated power electronic "voltage-power-quality" distribution network compensation system according to claim 1 is characterized in that: The energy interaction modes between the third voltage-type reversible PWM converter (113) and the distribution network power supply line include: a power quality compensation mode and a power compensation mode, wherein the power quality compensation mode is used to inject compensation current into the power grid to achieve reactive power, harmonic and three-phase imbalance compensation of the distribution network power supply line; the power compensation mode is used to inject current into the power grid or absorb power grid current to achieve load peak and valley regulation of the distribution network line.

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