An electrified railway same-phase energy storage power supply system and control method

Abstract

The present invention provides an electrified railway co-phase energy storage power supply system and a control method, which relate to the technical field of electrified railway traction power supply, and include a traction transformer, a photovoltaic co-phase energy storage device, a current transformer arranged on a traction feeder, and a voltage transformer on a co-phase traction bus; the photovoltaic co-phase energy storage device is composed of a co-phase photovoltaic bridge arm, a capacitor bridge arm, and a co-phase energy storage bridge arm; the traction transformer adopts a three-phase / two-phase wiring form, and the grid side is connected to a three-phase power system, wherein a one-phase traction side winding is directly connected to the co-phase traction bus, and the other-phase traction side winding is connected to the co-phase traction bus through a photovoltaic co-phase energy storage device, and the co-phase power supply bus is connected to the traction network through a feeder; the voltage transformer and the current transformer measuring ends are respectively connected to the detection signal input end of the measurement and control unit, and the control signal output end of the measurement and control unit is connected to the control end of the photovoltaic co-phase energy storage device.

Description

Technical Field

[0001] The invention relates to the technical field of electrified railway traction power supply. Background Art

[0002] With the development of high-speed and heavy-load electric traction on electrified railways and the rapid promotion and application of AC, DC and AC trains, the power and transportation volume of a single vehicle have increased dramatically. The traction power supply system has shown new characteristics such as obvious negative sequence content and prominent electrical transients caused by electrical phase separation. The same-phase power supply technology has solved the above problems and is an ideal power supply solution. However, when electric locomotives stop and slow down or go downhill, a large amount of regenerative braking energy will be generated. Since it is unplanned power generation, it will have an adverse effect on the power grid. The use of energy storage devices to store and utilize the regenerative braking energy of trains can not only reduce the impact on the public power grid, but also save energy loss and smooth out traction load fluctuations. Therefore, adding energy storage technology on the basis of same-phase power supply will further improve the performance of traction power supply.

[0003] At present, there are energy storage solutions based on single-phase power supply, which realize the same-phase energy storage function by setting energy storage devices on the AC bus. This solution has a simple structure and obvious advantages. However, when the energy storage device is not enough to control the negative sequence content within the national standard range, it is necessary to supplement it with other power quality management devices. There are also energy storage solutions that use AC-DC-AC same-phase power supply technology, by setting energy storage devices on the DC bus of the AC-DC-AC converter. Since the same-phase power supply converter mostly adopts cascade topology, the number of its DC buses is relatively large, which increases the technical difficulty and cost of energy storage device integration, and also affects the independence and flexibility of energy storage device configuration to a certain extent. In addition, most energy storage devices are coupled with the AC system of the traction transformer through a transformer. There are transformer losses in both the charging and discharging processes, which reduces the utilization rate of regenerative braking energy. At the same time, the footprint and noise of the transformer are other factors that cannot be ignored. Especially when the transformer is a multi-winding transformer, the above problems are more serious.

[0004] As a green energy source, photovoltaic power generation is beneficial to energy conservation and emission reduction when connected to the traction power supply system, and has certain economic benefits. The connection of photovoltaic power generation to the energy storage power supply system and the use of energy storage devices to form a complementary advantage between photovoltaic power generation and energy storage are of great significance to further improve the performance and economic benefits of the traction power supply system.

[0005] How to combine energy storage technology and photovoltaic power generation with co-phase power supply to implement safe, reliable and energy-saving power supply for electrified railways is a hot topic in the industry. Summary of the invention

[0006] The purpose of the present invention is to provide a co-phase energy storage power supply system for electrified railways, which can effectively solve the technical problem of safe and reliable power supply for electrified railways.

[0007] Another object of the present invention is to provide a control method for an electrified railway co-phase energy storage power supply system, which can effectively solve the technical problem of controlling a safe and reliable power supply system for an electrified railway.

[0008] The object of the present invention is achieved through the following technical solutions: an electrified railway co-phase energy storage power supply system, comprising a traction transformer, a photovoltaic co-phase energy storage device, and a current transformer arranged on a traction feeder and a voltage transformer on a co-phase traction bus, wherein the measuring ends of the current transformer and the voltage transformer are respectively connected to the detection signal input end of a measurement and control unit, and the photovoltaic co-phase energy storage device is composed of a co-phase photovoltaic bridge arm M S1 and M S2 , capacitor bridge arms C1 and C2 and the same-phase energy storage bridge arm M T1 and M T2 Composition, same phase photovoltaic bridge arm M S1 and M S2 The SL1 branch is formed by connecting the connection point L1 in series, and the capacitor bridge arms C1 and C2 are connected in series through the connection point L2 to form the SL2 branch. T1 and M T2 The SL3 branch is formed by connecting in series through the series connection point L3, and the branches SL1, SL2 and SL3 form a parallel circuit; the traction transformer is a three-phase / two-phase connection form, and the grid side is connected to the three-phase power system. One end of the first winding a on the traction side is grounded, and the other end is connected to the same-phase traction bus. One end of the second winding b on the traction side is connected to the series connection point L1 of the photovoltaic same-phase energy storage device, and the other end is connected to the series connection point L2 of the photovoltaic same-phase energy storage device and grounded. The series connection point L3 of the photovoltaic same-phase energy storage device is connected to the same-phase traction bus, and the same-phase power supply bus is connected to the traction network through the traction feeder; the control signal output end of the measurement and control unit is respectively connected to the same-phase photovoltaic bridge arm M of the photovoltaic same-phase energy storage device. S1 and M S2 The control end and the same phase energy storage bridge arm M T1 and M T2 The control end connection.

[0009] The same-phase photovoltaic bridge arm M S1 and M S2 The same structure, all of which are composed of n power photovoltaic modules PM1, PM2, ..., PM n The power photovoltaic module consists of two IGBT devices T connected in series with an inductor L. P1 and T P2 After connecting in series with a capacitor C P0 The single-phase half-bridge structure formed in parallel is in capacitor C P0 The side is connected in parallel with the photovoltaic device PV, where n≥1.

[0010] The same-phase energy storage bridge arm M T1 and M T2The same structure, both of which are composed of n power storage modules TM1, TM2, ..., TM n The power storage module is composed of two IGBT devices T T1 and T T2 After connecting in series with a capacitor C T0 The single-phase half-bridge structure formed in parallel is in capacitor C T0 The side is connected in parallel with the energy storage device ESD, where n≥1.

[0011] The traction transformer is SCOTT connection, YNd11 or Vv connection.

[0012] The voltage transformer is used to measure the voltage of the same-phase traction bus, and the current transformer is used to measure the current of the traction feeder.

[0013] The energy storage medium of the energy storage device ESD is one of electromagnetic energy storage, physical energy storage or electrochemical energy storage.

[0014] Another object of the present invention is to achieve the following technical solution: A control method for controlling a photovoltaic-containing electrified railway co-phase energy storage power supply system as described in any one of claims 1 to 6, wherein the grid negative sequence power allowable value P is known. N and discharge threshold P D , the rated power of the energy storage device ESD is P ESD The control method includes: the measurement and control unit obtains the voltage data and current data transmitted by the voltage transformer and the current transformer respectively; calculates the active power S of the traction load according to the voltage data and the current data; obtains the photovoltaic device power P PV ;

[0015] Step 1: The measurement and control unit determines whether the active power S of the traction load is less than zero. If so, it controls n power storage modules TM1, TM2, ..., TM n Charge and control n power photovoltaic modules PM1, PM2, ..., PM n Standby, otherwise, go to step 2; at this time, the power storage modules TM1, TM2, ..., TM n The charging power is S C , then:

[0016] When -S<P ESD When S C =-S;

[0017] When -S ≥ P ESD When S C =P ESD ;

[0018] Step 2: The measurement and control unit determines whether the traction load active power S is less than the discharge threshold PD +P PV If yes, control n power storage modules TM1, TM2, ..., TM n Standby and control n power photovoltaic modules PM1, PM2, ..., PM n Power generation, otherwise, go to step 3; at this time, the power photovoltaic modules PM1, PM2, ..., PM n Power generation S P For S and P PV The minimum of the two;

[0019] Step 3: The measurement and control unit determines whether the active power S of the traction load is less than the allowable value P of the negative sequence power of the power grid N If yes, control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step 4; at this time, the power storage modules TM1, TM2, ..., TM n The discharge power of the discharge is S D , then:

[0020] When S<P ESD When S D =S;

[0021] When S ≥ P ESD When S D =P ESD ;

[0022] At this time, the power photovoltaic modules PM1, PM2, ..., PM n Power generation S P P PV ;

[0023] Step 4: The measurement and control unit controls n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generates power and transmits active power to the traction side; at this time, the power storage modules TM1, TM2, …, TM n The discharge power of the discharge is S D , power photovoltaic modules PM1,PM2,…,PM n Power generation S P P PV , the active power transmitted to the traction side is P T , then:

[0024] When S<P ESD When S D =S;

[0025] When S ≥ P ESD When S D =P ESD ;

[0026] When S<S D +P N +P PV , P T =0;

[0027] When S ≥ S D +P N +P PV , P T =(SS D -P N -P PV ) / 2; where P N >0,P D >0,P PV ≥0.

[0028] The rated power P of the energy storage device ESD ESD and discharge threshold P D Through the load active power S and photovoltaic power P PV The historical value is optimized and the grid negative sequence power allowable value P is obtained. N Determined by the grid capacity and power quality voltage imbalance index.

[0029] The measurement and control unit comprises:

[0030] Data acquisition module: used to obtain the voltage data and current data transmitted by the voltage transformer and current transformer and the power P of the photovoltaic device PV ;

[0031] Calculation module: used for calculating the active power S of the traction load according to the voltage data and the current data;

[0032] The first module is used to determine whether the active power S of the traction load is less than zero. If so, it controls n power storage modules TM1, TM2, ..., TM n Charge and control n power photovoltaic modules PM1, PM2, ..., PM n Standby, otherwise, enter the second module;

[0033] The second module is used to determine whether the active power S of the traction load is less than the discharge threshold P D +P PV If yes, control n power storage modules TM1, TM2, ..., TM n Standby and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step three;

[0034] The third module is used to determine whether the active power S of the traction load is less than the allowable value P of the negative sequence power of the power grid. N If yes, control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step 4;

[0035] The fourth module: used to control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generates power and transmits active power to the traction side.

[0036] The advantages and effects of the present invention compared with the prior art are as follows:

[0037] 1. Eliminating the matching transformer on the traction side reduces transformer losses during charging and discharging, and improves the utilization rate of regenerative braking energy;

[0038] Second, modular construction is conducive to the independence, flexibility, scalability and redundant backup of photovoltaic and energy storage device configurations;

[0039] 3. The present invention has advanced technology and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the first electrified railway co-phase energy storage and power supply system of the present invention.

[0041] Figure 2 It is a structural schematic diagram of the second electrified railway co-phase energy storage power supply system of the present invention.

[0042] Figure 3 It is a structural schematic diagram of the third electrified railway co-phase energy storage power supply system of the present invention.

[0043] Figure 4 It is a schematic diagram of a same-phase photovoltaic bridge arm structure shown in an embodiment of the present invention.

[0044] Figure 5 It is a schematic diagram of a same-phase energy storage bridge arm structure shown in an embodiment of the present invention.

[0045] Figure 6 It is a schematic diagram of a co-phase power supply bridge arm structure shown in an embodiment of the present invention.

[0046] FIG. 7 (a, b, c) is an exploded view of the entire flow chart of the present invention.

[0047] Figure 8It is a structural block diagram of the measurement and control unit of the present invention.

[0048] Figure numerals: 1—traction transformer, 1a—first winding a on the traction side of the traction transformer, 1b—second winding b on the traction side of the traction transformer, 2—photovoltaic same-phase energy storage device, 3—same-phase traction bus, 4—traction feeder, 5—measurement and control unit, 6—voltage transformer, 7—current transformer. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment provides an electrified railway co-phase energy storage power supply system, including a traction transformer 1, a photovoltaic co-phase energy storage device 2, and a voltage transformer 6 arranged on a co-phase traction bus 3 and a current transformer 7 arranged on a traction feeder 4, wherein the measuring ends of the voltage transformer 6 and the current transformer 7 are respectively connected to the detection signal input end of the measurement and control unit 5, and the characteristics are: the photovoltaic co-phase energy storage device 2 is composed of a co-phase photovoltaic bridge arm M S1 and M S2 , capacitor bridge arms C1 and C2 and the same-phase energy storage bridge arm M T1 and M T2 Composition, same phase photovoltaic bridge arm M S1 and M S2 The SL1 branch is formed by connecting the connection point L1 in series, and the capacitor bridge arms C1 and C2 are connected in series through the connection point L2 to form the SL2 branch. T1 and M T2 The SL3 branch is formed by connecting in series through the series connection point L3, and the branches SL1, SL2 and SL3 form a parallel circuit; the traction transformer 1 is a three-phase / two-phase connection form, and the grid side is connected to the three-phase power system. One end of the first winding a on the traction side is grounded, and the other end is connected to the same-phase traction bus 3. One end of the second winding b on the traction side is connected to the series connection point L1 of the photovoltaic same-phase energy storage device 2, and the other end is connected to the series connection point L2 of the photovoltaic same-phase energy storage device 2 and grounded. The series connection point L3 of the photovoltaic same-phase energy storage device 2 is connected to the same-phase traction bus 3, and the same-phase power supply bus 3 is connected to the traction network through the traction feeder 4; the control signal output end of the measurement and control unit 5 is respectively connected to the same-phase photovoltaic bridge arm M of the photovoltaic same-phase energy storage device 2. S1 and M S2 The control end and the same phase energy storage bridge arm M T1 and M T2 The control end connection.

[0052] As a preference, the traction transformer 1 adopts SCOTT connection, such as Figure 1 As shown; as another preferred embodiment, the traction transformer 1 adopts a single-phase three-phase combined wiring, such as Figure 2 As shown; as another preferred embodiment, the traction transformer 1 adopts Vv connection, such as Figure 3 As shown; in addition, the traction transformer 1 can also be connected in Vx wiring and other ways.

[0053] As a preferred embodiment, the same-phase photovoltaic bridge arm M S1 and M S2 The same structure, all of which are composed of n power photovoltaic modules PM1, PM2, ..., PM n The power photovoltaic module consists of two IGBT devices T connected in series with an inductor L. P1 and T P2 After connecting in series with a capacitor C P0 The single-phase half-bridge structure formed in parallel is in capacitor C P0 The side is connected in parallel with the photovoltaic device PV, such as Figure 4 As shown, where n≥1.

[0054] As a preferred embodiment, the same-phase energy storage bridge arm M T1 and M T2 The same structure, both of which are composed of n power storage modules TM1, TM2, ..., TM n The power storage module is composed of two IGBT devices T T1 and T T2 After connecting in series with a capacitor C T0 The single-phase half-bridge structure formed in parallel is in capacitor C T0 The side is connected in parallel with the energy storage device ESD, such as Figure 5 As shown, n≥1. In this embodiment, the energy storage medium of the energy storage device ESD may be one of electromagnetic energy storage, physical energy storage and electrochemical energy storage.

[0055] It should be noted that, as a special case, when the power of the photovoltaic device PV is zero or does not contain the photovoltaic device PV, the same-phase photovoltaic bridge arm M S1 and M S2 Converted into a common-phase power supply bridge arm, such as Figure 6 As shown, at this time, the bridge arm can only transmit power but has no power generation function.

[0056] It should be noted that when the energy storage medium of the energy storage device ESD is a super capacitor with a wide voltage range, a DC / DC converter is required to stabilize the power storage modules TM1, TM2, ..., TM n Capacitor C T0 The side DC voltage is within the specified range, that is, the energy storage device ESD is composed of energy storage medium and DC / DC converter, and is connected to the capacitor C through DC / DC T0 Form a parallel connection.

[0057] Preferably, the voltage transformer 6 is used to measure the voltage of the same-phase power supply bus 3 , and the current transformer 7 is used to measure the current of the feeder 4 .

[0058] The measurement and control unit 5 measures the traction load power S via the voltage transformer 6 and the current transformer 7, and controls the photovoltaic in-phase energy storage device 2 accordingly, utilizing regenerative braking energy, load peak elimination and power quality control.

[0059] Example 2

[0060] As shown in FIG. 7 , this embodiment provides a control method for controlling the photovoltaic-containing electrified railway co-phase energy storage power supply system provided in Embodiment 1, which is applied to the measurement and control unit, and the grid negative sequence power allowable value P is known. N and discharge threshold P D , the rated power of the energy storage device ESD is P ESD , the control method comprises:

[0061] Acquiring real-time data: The measurement and control unit 5 acquires the voltage data and current data measured by the voltage transformer 6 and the current transformer 7 respectively; and acquires the power P of the photovoltaic device. PV ;

[0062] Calculate real-time power: Calculate the active power S of the traction load based on the voltage data and current data;

[0063] Step 1: The measurement and control unit 5 determines whether the active power S of the traction load is less than zero. If so, it controls n power storage modules TM1, TM2, ..., TM n Charge and control n power photovoltaic modules PM1, PM2, ..., PM n Standby, otherwise, go to step 2; at this time, the power storage modules TM1, TM2, ..., TM n The charging power is S C , then:

[0064] When -S<P ESD When S C =-S;

[0065] When -S ≥ P ESD When S C =P ESD ;

[0066] Step 2: The measurement and control unit 5 determines whether the traction load active power S is less than the discharge threshold P D +P PV If yes, control n power storage modules TM1, TM2, ..., TM n Standby and control n power photovoltaic modules PM1, PM2, ..., PM nPower generation, otherwise, go to step 3; at this time, the power photovoltaic modules PM1, PM2, ..., PM n Power generation S P For S and P PV The minimum of the two;

[0067] Step 3: The measurement and control unit 5 determines whether the active power S of the traction load is less than the allowable value P of the negative sequence power of the power grid N If yes, control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step 4; at this time, the power storage modules TM1, TM2, ..., TM n The discharge power of the discharge is S D , then:

[0068] When S<P ESD When S D =S;

[0069] When S ≥ P ESD When S D =P ESD ;

[0070] At this time, the power photovoltaic modules PM1, PM2, ..., PM n Power generation S P P PV ;

[0071] Step 4: The measurement and control unit 5 controls n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generates power and transmits active power to the traction side; at this time, the power storage modules TM1, TM2, …, TM n The discharge power of the discharge is S D , power photovoltaic modules PM1,PM2,…,PM n Power generation S P P PV , the active power transmitted to the traction side is P T , then:

[0072] When S<P ESD When S D =S;

[0073] When S ≥ P ESD When S D =P ESD ;

[0074] When S<SD +P N +P PV , P T =0;

[0075] When S ≥ S D +P N +P PV , P T =(SS D -P N -P PV ) / 2; where P N >0,P D >0,P PV ≥0.

[0076] The rated power P of the energy storage device ESD ESD and discharge threshold P D Through the load active power S and photovoltaic power P PV The historical value is optimized and the grid negative sequence power allowable value P is obtained. N Determined by the grid capacity and power quality voltage imbalance index.

[0077] It should be noted that when the power of the photovoltaic device PV is zero or does not contain the photovoltaic device PV, the photovoltaic power P in this embodiment is PV is zero.

[0078] Example 3

[0079] like Figure 8 As shown, this embodiment provides a measurement and control unit for implementing the control method described in Embodiment 2, including:

[0080] Data acquisition module: used to acquire the voltage data and current data transmitted by the voltage transformer 6 and the current transformer 7 and the power P of the photovoltaic device PV ;

[0081] Calculation module: used for calculating the active power S of the traction load according to the voltage data and the current data;

[0082] The first module is used to determine whether the active power S of the traction load is less than zero. If so, it controls n power storage modules TM1, TM2, ..., TM n Charge and control n power photovoltaic modules PM1, PM2, ..., PM n Standby, otherwise, enter the second module;

[0083] The second module is used to determine whether the active power S of the traction load is less than the discharge threshold P D +P PV If yes, control n power storage modules TM1, TM2, ..., TM nStandby and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step three;

[0084] The third module is used to determine whether the active power S of the traction load is less than the allowable value P of the negative sequence power of the power grid. N If yes, control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step 4;

[0085] The fourth module is used to control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generates power and transmits active power to the traction side.

[0086] It should be noted that when the power of the photovoltaic device PV is zero or does not contain the photovoltaic device PV, the photovoltaic power P in this embodiment is PV is zero.

[0087] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An electrified railway co-phase energy storage power supply system, comprising a traction transformer (1), a photovoltaic co-phase energy storage device (2), and a voltage transformer (6) arranged on a co-phase traction bus (3) and a current transformer (7) arranged on a traction feeder (4), wherein the measuring ends of the voltage transformer (6) and the current transformer (7) are respectively connected to the detection signal input end of a measurement and control unit (5), and characterized in that: The photovoltaic same-phase energy storage device (2) consists of the same-phase photovoltaic bridge arm M S1 and M S2 , capacitor bridge arms C1 and C2 and the same-phase energy storage bridge arm M T1 and M T2 Composition, same phase photovoltaic bridge arm M S1 and M S2 The SL1 branch is formed by connecting the connection point L1 in series, and the capacitor bridge arms C1 and C2 are connected in series through the connection point L2 to form the SL2 branch. T1 and M T2 The SL3 branch is formed by connecting in series through the series connection point L3, and the branches SL1, SL2 and SL3 form a parallel circuit; the traction transformer (1) is in a three-phase / two-phase connection form, and the grid side is connected to the three-phase power system; one end of the first winding a on the traction side is grounded, and the other end is connected to the same-phase traction bus (3); one end of the second winding b on the traction side is connected to the series connection point L1 of the photovoltaic same-phase energy storage device (2), and the other end is connected to the series connection point L2 of the photovoltaic same-phase energy storage device (2) and grounded; the series connection point L3 of the photovoltaic same-phase energy storage device (2) is connected to the same-phase traction bus (3), and the same-phase traction bus (3) is connected to the traction grid through the traction feeder (4); the control signal output end of the measurement and control unit (5) is respectively connected to the same-phase photovoltaic bridge arm M of the photovoltaic same-phase energy storage device (2) S1 and M S2 The control end and the same phase energy storage bridge arm M T1 and M T2 The control end connection.

2. The same-phase energy storage power supply system for an electrified railway according to claim 1, characterized in that: The same-phase photovoltaic bridge arm M S1 and M S2 The same structure, all of which are composed of n power photovoltaic modules PM1, PM2, ..., PM n The power photovoltaic module consists of two IGBT devices T connected in series with an inductor L. P1 and T P2 After connecting in series with a capacitor C P0 The single-phase half-bridge structure formed in parallel is in capacitor C P0 The side is connected in parallel with the photovoltaic device PV, where n≥1.

3. The same-phase energy storage power supply system for an electrified railway according to claim 1, characterized in that: The same-phase energy storage bridge arm M T1 and M T2 The same structure, both of which are composed of n power storage modules TM1, TM2, ..., TM n The power storage module is composed of two IGBT devices T T1 and T T2 After connecting in series with a capacitor C T0 The single-phase half-bridge structure formed in parallel is in capacitor C T0 The side is connected in parallel with the energy storage device ESD, where n≥1.

4. The same-phase energy storage power supply system for an electrified railway according to claim 1, characterized in that: The traction transformer (1) is a SCOTT connection, a YNd11 connection or a Vv connection.

5. The same-phase energy storage power supply system for electrified railway according to claim 1, characterized in that: The voltage transformer (6) is used to measure the voltage of the same-phase traction bus (3), and the current transformer (7) is used to measure the current of the traction feeder (4).

6. The same-phase energy storage power supply system for electrified railway according to claim 3, characterized in that: The energy storage medium of the energy storage device ESD is one of electromagnetic energy storage, physical energy storage or electrochemical energy storage.

7. A control method for controlling the electric railway co-phase energy storage power supply system according to any one of claims 1 to 6, wherein the permissible value of the negative sequence power of the power grid P is known. N and discharge threshold P D , the rated power of the energy storage device ESD is P ESD , the control method comprises: The measurement and control unit (5) respectively obtains voltage data and current data measured by the voltage transformer (6) and the current transformer (7); The active power S of the traction load is calculated based on the voltage data and the current data; Get the photovoltaic power P PV ; Step 1: The measurement and control unit (5) determines whether the active power S of the traction load is less than zero. If so, it controls n power storage modules TM1, TM2, ..., TM n Charge and control n power photovoltaic modules PM1, PM2, ..., PM n Standby, otherwise, go to step 2; at this time, the power storage modules TM1, TM2, ..., TM n The charging power is S C , then: When -S<P ESD When S C =-S; When -S ≥ P ESD When S C =P ESD ; Step 2: The measurement and control unit (5) determines whether the active power S of the traction load is less than the discharge threshold P D +P PV If yes, control n power storage modules TM1, TM2, ..., TM n Standby and control n power photovoltaic modules PM1, PM2, ..., PM n Power generation, otherwise, go to step 3; at this time, the power photovoltaic modules PM1, PM2, ..., PM n Power generation S P For S and P PV The minimum of the two; Step 3: The measurement and control unit (5) determines whether the active power S of the traction load is less than the allowable value P of the negative sequence power of the power grid N If yes, control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step 4; at this time, the power storage modules TM1, TM2, ..., TM n The discharge power of the discharge is S D , then: When S<P ESD When S D =S; When S ≥ P ESD When S D =P ESD ; At this time, the power photovoltaic modules PM1, PM2, ..., PM n Power generation S P P PV ; Step 4: The measurement and control unit (5) controls n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generates power and transmits active power to the traction side; at this time, the power storage modules TM1, TM2, ..., TM n The discharge power of the discharge is S D , power photovoltaic modules PM1,PM2,…,PM n Power generation S P P PV , the active power transmitted to the traction side is P T , then: When S<P ESD When S D =S; When S ≥ P ESD When S D =P ESD ; When S<S D +P N +P PV , P T =0; When S ≥ S D +P N +P PV , P T =(SS D -P N -P PV ) / 2; where P N >0,P D >0,P PV ≥0.

8. The method for controlling a co-phase energy storage power supply system for an electrified railway according to claim 7, characterized in that: The rated power P of the energy storage device ESD ESD and discharge threshold P D Through the load active power S and photovoltaic power P PV The historical value is optimized and the grid negative sequence power allowable value P is obtained. N Determined by the grid capacity and power quality voltage imbalance index.

9. The control method of the electrified railway co-phase energy storage power supply system according to claim 7, characterized in that: The measurement and control unit (5) comprises: Data acquisition module: used to acquire voltage data and current data transmitted by the voltage transformer (6) and the current transformer (7) and the power P of the photovoltaic device PV ; Calculation module: used for calculating the active power S of the traction load according to the voltage data and the current data; The first module is used to determine whether the active power S of the traction load is less than zero. If so, it controls n power storage modules TM1, TM2, ..., TM n Charge and control n power photovoltaic modules PM1, PM2, ..., PM n Standby, otherwise, enter the second module; The second module is used to determine whether the active power S of the traction load is less than the discharge threshold P D +P PV If yes, control n power storage modules TM1, TM2, ..., TM n Standby and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step three; The third module is used to determine whether the active power S of the traction load is less than the allowable value P of the negative sequence power of the power grid. N If yes, control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generate electricity, otherwise, go to step 4; The fourth module is used to control n power storage modules TM1, TM2, ..., TM n Discharge and control n power photovoltaic modules PM1, PM2, ..., PM n Generates power and transmits active power to the traction side.

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