Energy storage single-phase power supply system based on V-connected traction transformer, control method and storage medium

Abstract

The present invention discloses an energy storage in-phase power supply system, a control method and a storage medium based on a V-connected traction transformer, belonging to the technical field of electrified railway power supply. The energy storage in-phase power supply system includes a V-connected traction transformer, three single-phase compensation devices, an energy storage device and a coordinated control device. The primary side of the V-connected traction transformer is connected to a three-phase power supply, and any port of the secondary side is connected to a traction load; the AC ends of the three single-phase compensation devices are respectively connected to different ports of the secondary side, and the DC ends are connected in parallel to a DC bus; the energy storage device is also connected in parallel to the DC bus. The coordinated control device collects various current and voltage signals and controls the operation of each device. The present invention has the functions of energy storage and in-phase power supply, and solves the problems of large fluctuations in traction load of traditional electrified railway traction substations, power feedback caused by train regenerative braking, train stalling when passing through phase separation, and power quality improvement.

Description

Technical Field

[0001] The present invention relates to the technical field of electrified railway power supply, and particularly to an energy storage in-phase power supply system based on a V-connected traction transformer, a control method for an energy storage in-phase power supply system based on a V-connected traction transformer, and a computer-readable storage medium. Background Art

[0002] The electrified railways in China adopt the industrial frequency single-phase AC traction power supply system. In recent years, with the development of high-speed railways and heavy-haul railways and the popularization and application of AC-DC-AC trains, the power of a single train has also increased sharply. On the one hand, the single-phase and mobile traction loads generated by high-power trains have caused the power quality of the traction power supply system to have an impact on the power system mainly in the form of three-phase imbalance. On the other hand, when the AC-DC-AC train decelerates and brakes, it mainly uses regenerative braking to convert the kinetic energy of the train into electrical energy. Although it is beneficial to energy conservation and consumption reduction, it also leads to a drastic fluctuation in the load power of the train, and even sends the power back to the power system, which not only increases the operating cost of the traction power supply system, but also affects the safe and stable operation of the power system. In addition, there are also electrical phase separators in the traction power supply system, resulting in discontinuous train power supply, affecting the train running speed, and the on-off of the switch during the train passing through the phase separator causes electrical transients and other problems, affecting the safe and reliable operation of the train.

[0003] To improve the impact of electrified railways on the power quality of the public power grid, solutions such as reactive power compensation devices, active filters, and railway power regulators can be adopted. However, limited by the traction power supply mode and system structure, the above solutions can well solve the power quality problems, but cannot eliminate the overhead contact line electrical phase separator. Most trains in China are also equipped with automatic phase separator passing devices, which can automatically control the on-off of the switch to enable the train to pass through the phase separator, but still cannot eliminate the electrical transient problems caused by the on-off of the switch, nor can they solve the power quality problems. The researchers of this team proposed an in-phase power supply system, which uses passive compensation technology or active compensation technology to form an in-phase power supply system, which can comprehensively manage power quality problems such as negative sequence, reactive power, and harmonics, and at the same time cancel the overhead contact line electrical phase separator, and is considered to be an ideal electrified railway power supply solution.

[0004] In recent years, energy storage, as an important part of the smart grid and the high-proportion renewable energy power generation system, has developed rapidly. The installed capacity of the energy storage system has increased significantly, which has better smoothed the volatility of renewable energy power generation and played an important role in peak shaving and valley filling, power support and flexible control of the power system, and building a "clean, low-carbon, safe and efficient" energy industry system. How to combine power quality control, elimination of the overhead contact line electrical phase separator and energy storage to construct a new energy storage in-phase power supply system is a topic worthy of exploration. Summary of the Invention

[0005] The object of the present invention is to provide an energy storage in-phase power supply system, a control method and a storage medium based on a V-connected traction transformer, which have the functions of energy storage and in-phase power supply, and solve the problems of large fluctuations in traction load of traditional electrified railway traction substations, utilization of train regenerative braking energy, train stalling during passing over neutral sections, and power quality improvement.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] An energy storage in-phase power supply system based on a V-connected traction transformer, the energy storage in-phase power supply system comprising:

[0008] A V-connected traction transformer TT for transforming the external power supply on the primary side to the traction bus on the secondary side. The primary side of the V-connected traction transformer TT is connected to a three-phase power system PS, and the three terminals on the secondary side of the V-connected traction transformer TT are respectively connected to a first traction bus BB T1 , a second traction bus BB T2 and a grounding electrode GD. A traction load TL is connected between the first traction bus BB T1 and the grounding electrode GD;

[0009] A single-phase compensation device for charge and discharge power conversion and power quality compensation, including a first single-phase compensation device CD 1 , a second single-phase compensation device CD 2 and a third single-phase compensation device CD 3 ;

[0010] An energy storage device ES for charge and discharge power conversion and energy storage or release. The positive electrode of the energy storage device ES is connected to a first DC bus BB D1 , and the negative electrode is connected to a second DC bus BB D2 ;

[0011] A coordinated control device CS for detecting the operating parameters of the traction load and the energy storage device ES, and controlling the operation of the single-phase compensation device and the energy storage device ES to achieve charge and discharge power conversion and power quality compensation. The input end of the coordinated control device CS is connected to the following signals:

[0012] The secondary side signal i T1 of the current transformer LH L connected in series with the traction load feeder by the first traction bus BB L , the secondary side signal i 1 of the current transformer LH T1 connected in series with the AC end of the first single-phase compensation device CD by the first traction bus BB 1 , the secondary side signal i CD1 of the current transformer LH 2 connected in series with the AC end of the second single-phase compensation device CD by the grounding electrode GD2 secondary side signal i CD2 , the third single-phase compensation device CD 3 The AC terminal is connected to the second traction bus BB T2 by the series-connected current transformer LH 3 secondary side signal i CD3 , the energy storage device ES is connected to the first DC bus BB D1 by the series-connected DC current sensor LH ES secondary side signal i ES , and the voltage transformer YH of the first traction bus BB T1 secondary side signal u T1 secondary side signal u T1 , the voltage transformer YH of the second traction bus BB T2 secondary side signal u T2 secondary side signal u T2 , connected to the first DC bus BB D1 and the second DC bus BB D2 by the DC voltage sensor YH D secondary side signal u D ;

[0013] The bidirectional signal ports of the coordination control device CS are respectively connected to the bidirectional signal ports of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 , the third single-phase compensation device CD 3 and the energy storage device ES.

[0014] Preferably, the AC terminals of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 are respectively connected to three different ports on the secondary side of the V-connected traction transformer TT, and their DC positive poles are connected in parallel and connected to the first DC bus BB D1 , and their DC negative poles are connected in parallel and connected to the second DC bus BB D2 ;

[0015] The first single-phase compensation device CD 1 includes a first matching transformer MT connected in cascade 1 and a first single-phase AC-DC converter AD 1 , the second single-phase compensation device CD 2 includes a second matching transformer MT connected in cascade 2 and a second single-phase AC-DC converter AD 2 , the third single-phase compensation device CD 3 includes a third matching transformer MT connected in cascade 3 and a third single-phase AC-DC converter AD3 。

[0016] Preferably, the energy storage device ES includes a DC-DC converter DD and an energy storage module SM connected in cascade in sequence.

[0017] Preferably, the energy storage in-phase power supply system further includes a standby V-connected traction transformer TB serving as a standby transformer for the V-connected traction transformer TT. The primary side of the standby V-connected traction transformer TB is connected to the three-phase power system PS, and any one port of the secondary side of the standby V-connected traction transformer TB is connected to the traction load TL; three different ports of the secondary side of the standby V-connected traction transformer TB also correspond one-to-one to the AC terminals of the first single-phase compensation device CD 1 、the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 are connected.

[0018] A second aspect of the present invention provides a control method for an energy storage in-phase power supply system based on a V-connected traction transformer as described in the above technical solution. The specific steps of the control method include:

[0019] Step 1. System initialization: The coordination control device CS performs electrical quantity definition.

[0020] Step 2. Charge and discharge power calculation: The coordination control device CS first calculates the active power and reactive power currently absorbed by the traction load TL, and detects the current state of charge SOC of the energy storage device ES through the bidirectional signal between the coordination control device CS and the energy storage device ES ES , and then determines the charge and discharge power of the energy storage device ES and the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 .

[0021] Step 3. Power quality compensation power calculation: The coordination control device CS determines the power quality compensation power of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 according to the calculated charge and discharge power value.

[0022] Step 4. The coordination control device CS generates the combined output current of the energy storage device ES and the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 , and respectively controls the above devices to output current. After a preset time step △t, it returns to Step 2 and loops.

[0023] Preferably, the specific method for defining electrical quantities in step one is as follows:

[0024] The feeder current transformer LH of the traction load TL L The secondary side signal i L The polarity is defined as flowing into the traction load TL from the first traction busbar BB being positive. The voltage transformer YH of the first traction busbar BB T1 flows into the traction load TL as positive. The voltage transformer YH of the first traction busbar BB T1 The secondary side signal u T1 The polarity is defined as the corresponding end of the first traction busbar BB being positive and the corresponding end of the grounding electrode GD being negative. Based on the voltage transformer YH of the first traction busbar BB T1 The corresponding end of the first traction busbar BB T1 is positive, and the corresponding end of the grounding electrode GD is negative. Based on the voltage transformer YH of the first traction busbar BB T1 The secondary side signal u T1 and the feeder current transformer LH of the traction load TL T1 The secondary side signal i L The secondary side signal i L The active power P absorbed by the traction load TL is calculated L and the reactive power Q L and the harmonic current i Lh ; The voltage transformer YH of the second traction busbar BB T2 The secondary side signal u T2 The polarity is defined as the corresponding end of the second traction busbar BB being positive and the corresponding end of the grounding electrode GD being negative; T2 The corresponding end of the second traction busbar BB T2 is positive, and the corresponding end of the grounding electrode GD is negative;

[0025] The first single-phase compensation device CD connected to the first traction busbar BB together with the traction load TL T1 The secondary side signal of the current transformer at the AC end is defined as i 1 The polarity is defined as flowing into the first single-phase compensation device CD from the first traction busbar BB CD1 as positive. Based on the voltage transformer YH of the first traction busbar BB T1 flows into the first single-phase compensation device CD 1 as positive. Based on the voltage transformer YH of the first traction busbar BB T1 The secondary side signal u T1 The secondary side signal u T1 and the first single-phase compensation device CD 1 The secondary side signal i of the current transformer at the AC end CD1 The active power P absorbed by the AC end of the first single-phase compensation device CD is calculated 1 and the reactive power Q 1 and the reactive power Q 1 ;

[0026] The second single-phase compensation device CD connected between the second traction busbar BB and the grounding electrode GD T2 The secondary side signal of the current transformer at the AC end is defined as i 2 The secondary side signal of the current transformer at the AC end is defined as i CD2, the polarity is defined as flowing from the grounding electrode GD into the second single-phase compensation device CD 2 is positive, based on the second single-phase compensation device CD 2 the secondary side signal i of the AC terminal current transformer CD2 and the second traction bus BB T2 the voltage transformer YH T2 the secondary side signal u T2 the reverse-phase signal of which is used to calculate the active power P 2 absorbed by the AC terminal of the second single-phase compensation device CD 2 and the reactive power Q 2 ;

[0027] The third single-phase compensation device CD connected between the first traction bus BB T1 and the second traction bus BB T2 The secondary side signal of the AC terminal current transformer of the third single-phase compensation device CD is defined as i 3 , and the polarity is defined as positive when flowing from the second traction bus BB CD3 into the third single-phase compensation device CD T2 is positive, based on the third single-phase compensation device CD 3 the secondary side signal i of the AC terminal current transformer 3 and the second traction bus BB CD3 the voltage transformer YH T2 The secondary side signal u T2 and the voltage transformer YH of the first traction bus BB T2 The difference between the secondary side signal u T1 of which is used to calculate the active power P T1 absorbed by the AC terminal of the third single-phase compensation device CD T1 and the reactive power Q 3 ; 3

[0028] The secondary side signal i of the DC terminal current sensor LH of the energy storage device ES ES The polarity is defined as flowing into the first DC bus BB ES is positive, and the secondary side signal u of the DC terminal voltage sensor YH D1 The polarity is defined as positive for the corresponding terminal of the first DC bus BB D and negative for the corresponding terminal of the second DC bus BB D Based on the secondary side signal i of the DC terminal current sensor LH of the energy storage device ES D1 and the secondary side signal u of the DC voltage sensor YH D2 The active power P released by the energy storage device ES is calculated ES from the secondary side signal i ES and the secondary side signal u of the DC voltage sensor YH D D ; ES

[0029] ​​​​

[0029] Preferably, the specific method for determining the charge and discharge power in step two is as follows:

[0030] Update the sampling signals at all input terminals of the coordination control device CS, and use the voltage transformer YH T1 on the first traction bus BB T1 to obtain the secondary side signal u T1 and the feeder current transformer LH L on the traction load TL to obtain the secondary side signal i L and calculate the active power P L , reactive power Q L and harmonic current i Lh absorbed by the traction load TL;

[0031] Statistically analyze the historical operation of the traction load TL to obtain the historical average active power P Lav within a preset time length before the current moment; if there is no historical data on the traction load, set the initial value of the historical average active power P Lav to zero, and start to statistically analyze and calculate the average active power of the traction load after starting;

[0032] If the current state of charge SOC ES of the energy storage device ES is greater than the lower limit SOC min of its allowable state of charge and less than the upper limit SOC max of its allowable state of charge, where 0 < SOC min < SOC max < 1, then perform charge and discharge control: the target discharge power value of the energy storage device ES is P ES * = P L - P Lav , and the target active power value absorbed by the AC terminal of the first single-phase compensation device CD 1 is P 1 * = P Lav / 3 - P L , and the target active power values absorbed by the AC terminals of the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 are both taken as P 2 * = P 3 * = P Lav / 3;

[0033] If the current state of charge SOC ES of the energy storage device ES is less than or equal to the lower limit SOC min of its allowable state of charge, then perform the power shortage recovery control of the energy storage device ES and output an alarm prompt: the target discharge power value of the energy storage device ES is P ES * = - P RS , where PRS To restore the power of the energy storage device, which is a preset value greater than zero and less than the historical average active power P Lav The absolute value of, the first single-phase compensation device CD 1 The target value of the active power absorbed by the AC terminal P 1 * = P RS The second single-phase compensation device CD 2 And the third single-phase compensation device CD 3 The target values of the active power absorbed by the AC terminals are all taken as P 2 * = P 3 * = 0;

[0034] If the current state of charge SOC of the energy storage device ES ES Is greater than or equal to the upper limit SOC of its allowable state of charge max Then, perform overcharge recovery control of the energy storage device and output an alarm prompt: The target value of the discharge power of the energy storage device ES is P ES * = P RS The first single-phase compensation device CD 1 The target value of the active power absorbed by the AC terminal P 1 * = -P RS The second single-phase compensation device CD 2 And the third single-phase compensation device CD 3 The target values of the active power absorbed by the AC terminals are all taken as P 2 * = P 3 * = 0.

[0035] Preferably, the specific method for determining the power quality compensation power in step three is as follows:

[0036] Perform reactive power control: The first single-phase compensation device CD 1 The target value of the reactive power absorbed by the AC terminal Q 1 * Satisfies the reactive power Q absorbed by the traction load TL L ;

[0037] Perform harmonic current control: The first single-phase compensation device CD 1 The target value of the harmonic current absorbed by the AC terminal i 1h * Satisfies the harmonic current i absorbed by the traction load TL Lh ;

[0038] Perform negative sequence power control: If the current state of charge SOC of the energy storage device ES ES Is greater than the lower limit SOC of its allowable state of charge min And less than the upper limit SOC of its allowable state of charge max Then, do not perform negative sequence power control: The second single-phase compensation device CD 2 And the third single-phase compensation device CD3 The target reactive power absorbed by the AC side is set to zero;

[0039] If the current state of charge (SOC) of the energy storage device ES ES is less than or equal to the lower limit SOC of its allowable state of charge min , or the SOC ES is greater than or equal to the upper limit SOC of its allowable state of charge max , then further judgment is required. The rules for further judgment are as follows:

[0040] The allowable single-phase power reduced to the secondary side of the V-connected traction transformer TT according to the three-phase power system PS and the preset standard of three-phase voltage imbalance in power quality is represented by S AN , where S AN ≥0. If data is lacking and reduction is not possible, the allowable single-phase power S AN adopts a preset value; when the absolute value of the active power P L |P| L absorbed by the traction load TL is less than or equal to the allowable single-phase power S AN , no negative-sequence power control is performed, and the target reactive power absorbed by the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 is set to zero; if the absolute value |P| L is greater than the allowable single-phase power S AN , negative-sequence power control is performed, and further judgment is required. The rules for further judgment are as follows:

[0041] If P L >0, the target reactive power absorbed by the second single-phase compensation device CD 2 is set to Q 2 *=(S AN -P L ) / , and the target reactive power absorbed by the third single-phase compensation device CD 3 is set to Q 3 *=(P L -S AN ) / ; if P L <0, the target reactive power absorbed by the second single-phase compensation device CD 2 is set to Q 2 *=-(P L +S AN ) / , and the target reactive power absorbed by the third single-phase compensation device CD 3 is set to Q 3 *=(P L +SAN ) / 。

[0042] Preferably, the specific method for generating the comprehensive output current in step four is as follows:

[0043] The coordination control device CS detects the voltage transformer YH T1 on the secondary side signal u T1 of the first traction bus BB T1 and the voltage transformer YH T2 on the secondary side signal u T2 of the second traction bus BB T2 for the fundamental voltage phasor. If the fundamental voltage phase of the voltage transformer YH T1 on the secondary side signal u T1 of the first traction bus BB T1 leads the fundamental voltage phase of the voltage transformer YH T2 on the secondary side signal u T2 of the second traction bus BB T2 , then the target value P 2 of the active power absorbed by the AC terminal of the second single-phase compensation device CD 2 * is swapped with the target value P 3 of the active power absorbed by the AC terminal of the third single-phase compensation device CD 3 *, and the target value Q 2 of the reactive power absorbed by the AC terminal of the second single-phase compensation device CD 2 * is swapped with the target value Q 3 of the reactive power absorbed by the AC terminal of the third single-phase compensation device CD 3 *;

[0044] Based on the target value P 1 of the active power absorbed by the AC terminal of the first single-phase compensation device CD 1 *, the target value Q 1 * of the reactive power, the target value i 1h * of the harmonic current, and its port voltage signal u T1 , the target value i 1 of the port current signal of the first single-phase compensation device CD CD1 * is obtained; based on the target value P 2 of the active power absorbed by the AC terminal of the second single-phase compensation device CD 2 *, the target value Q 2 * of the reactive power, and its port voltage signal (-u T2 ), the target value i 2 of the port current signal of the second single-phase compensation device CD CD2 * is obtained; based on the target value P 3 of the active power absorbed by the AC terminal of the third single-phase compensation device CD 3*, reactive power target value Q 3 * and its port voltage signal (u T2 - u T1 ), to obtain the third single - phase compensation device CD 3 port current signal target value i CD3 *; According to the active power target value P ES * released by the DC side of the energy storage device ES and its port voltage signal u D , to obtain the port current signal target value i ES * of the energy storage device ES.

[0045] The third aspect of the present invention provides a computer - readable storage medium, on which instructions are stored, and when running on a computer, the computer is made to execute the above - mentioned control method for an energy - storage in - phase power supply system based on a V - connected traction transformer.

[0046] The working principle of the present invention is as follows: The coordination control device first detects the power of the traction load, compares it with the historical statistical value of the traction load, and then considers the state of charge of the energy storage device to calculate the charge - discharge power target values and power quality compensation power target values of the three single - phase compensation devices and the energy storage device. Further, the comprehensive output current target values of each device are generated respectively. The three single - phase compensation devices are controlled in a grid - connected manner to make them output according to the comprehensive output current target values respectively, and at the same time, the goals of charge - discharge control, in - phase power supply control, negative - sequence compensation control, reactive - power compensation control, and harmonic - compensation control are completed. The energy storage device converter is controlled in a grid - connected manner to make it output according to the comprehensive output current target value to complete the charge - discharge control goal, overcome the problems of large fluctuations in the traction load of traditional electrified railway traction substations, utilization of train regenerative braking energy, train stalling during passing through phase - separation sections, power quality management, etc., and is applicable to various traction power supply methods. The control method is simple and efficient, which is beneficial to improving the operation reliability of trains, increasing the utilization degree of train regenerative braking energy, reducing the electricity cost of traction substations, and reducing the impact of power fluctuations on the power system.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] 1. The present invention uses three single - phase compensation devices and an energy storage device for charge - discharge control and power quality control. Each device is relatively independent in structure, the control is simple and easy to implement. The three single - phase compensation devices and the energy storage device are connected in parallel at the DC side, and the DC voltage is stable, which is beneficial to the realization of the control goal;

[0049] 2. The present invention is applicable to energy - storage in - phase power supply of traction substations in situations such as Vv traction transformers, Vy traction transformers, etc., and is also applicable to traction power supply methods such as direct power supply method, direct power supply method with a return line, AT power supply method, BT power supply method, etc., with a wide range of applications;

[0050] 3. For the single-phase traction load of the present invention, the AC terminals of the three single-phase AC-DC converters can be connected to any port of the secondary side of the V-connected traction transformer without changing the control method, and the control method has good compatibility and strong versatility;

[0051] 4. The control method of the present invention realizes the integrated control of system charge and discharge, in-phase power supply and power quality. While charging and discharging, phase separation is cancelled, and negative sequence control, reactive power compensation, and harmonic suppression are carried out, which is beneficial to the continuous and reliable electrified operation of the train. It also realizes the active and reactive decoupling control of the single-phase compensation device, and the control method is simple and efficient;

[0052] 5. The control method of the present invention reduces the load fluctuation of the primary side of the traction substation. In an ideal situation, it can converge to the average power, effectively utilizes the regenerative braking feedback power and reduces the maximum demand power of the traction substation, which is beneficial to saving the electricity cost of the traction substation and can also reduce the impact of large-amplitude and high-frequency power fluctuations on the power system;

[0053] 6. The system structure and control method of the present invention can effectively control the power quality in the normal, power-deficient, and overcharged states of the energy storage device, with high operation flexibility and strong adaptability, ensuring that the power quality of the traction substation meets the national standards, which is beneficial to the safe and reliable operation of the railway and the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present application, but do not constitute a limitation to the embodiments of the present application. In the drawings:

[0055] Figure 1 is a schematic structural diagram of the energy storage in-phase power supply system based on the V-connected traction transformer described in Embodiment 1 of the present invention;

[0056] Figure 2 is a schematic structural diagram of the energy storage in-phase power supply system based on the V-connected traction transformer described in Embodiment 2 of the present invention;

[0057] Figure 3 is a schematic structural diagram of the energy storage in-phase power supply system based on the V-connected traction transformer described in Embodiment 3 of the present invention;

[0058] Figure 4 is a flowchart of the control method of the energy storage in-phase power supply system based on the V-connected traction transformer described in Embodiment 4 of the present invention;

[0059] Figure 5 is a specific flowchart for determining the charge and discharge power described in Embodiment 4 of the present invention;

[0060] Figure 6It is the specific flowchart of determining the power quality compensation power in Embodiment 4 of the present invention;

[0061] Figure 7 It is the specific flowchart of generating the comprehensive output current in Embodiment 4 of the present invention. Detailed implementation manners

[0062] To better understand the working principle of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The embodiments given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0063] Embodiment 1

[0064] As Figure 1 shown, this embodiment provides an energy storage in-phase power supply system based on a V-connected traction transformer. Among them, the energy storage in-phase power supply system includes a V-connected traction transformer TT for converting the external power supply provided by the three-phase power system into a voltage acceptable to the traction load, a single-phase compensation device for charge and discharge power conversion and power quality compensation, an energy storage device ES for charge and discharge power conversion and energy storage or release, and a coordinated control device CS for detecting the operating parameters of the traction load and the energy storage device and controlling the operation of the single-phase compensation device and the energy storage device to achieve coordinated control of charge and discharge power conversion and power quality compensation.

[0065] The primary side of the V-connected traction transformer TT is connected to the three-phase power system PS, and the three terminals of the secondary side of the V-connected traction transformer TT are respectively connected to the first traction bus BB T1 , the second traction bus BB T2 and the grounding electrode GD. A traction load TL is connected between the first traction bus BB T1 and the grounding electrode GD. Among them, the traction load TL is the total load shown by the traction network and the trains connected thereto in the case of the direct power supply method, the direct power supply method with a return line, and the BT power supply method; the single-phase compensation device is the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 . The AC ends of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 are respectively connected to three different ports of the secondary side of the V-connected traction transformer, and their DC positive poles are mutually connected in parallel and connected to the first DC bus BB D1 , and their DC negative poles are mutually connected in parallel and connected to the second DC bus BB D2 ; the positive pole of the energy storage device ES is connected to the first DC bus BB D1 , and its negative pole is connected to the second DC bus BBD2 ; The input end of the coordination control device CS is respectively connected to the current transformer LH connected in series by the first traction bus BB T1 on the traction load feeder L secondary side signal i L , the first single-phase compensation device CD 1 AC terminal by the first traction bus BB T1 connected in series with the current transformer LH 1 secondary side signal i CD1 , the second single-phase compensation device CD 2 AC terminal by the grounding electrode GD connected in series with the current transformer LH 2 secondary side signal i CD2 , the third single-phase compensation device CD 3 AC terminal by the second traction bus BB T2 connected in series with the current transformer LH 3 secondary side signal i CD3 , the energy storage device ES by the first DC bus BB D1 connected in series with the DC current sensor LH ES secondary side signal i ES , and the voltage transformer YH of the first traction bus BB T1 secondary side signal u T1 T1 , the voltage transformer YH of the second traction bus BB T2 secondary side signal u T2 T2 , the DC voltage sensor YH connected between the first DC bus BB D1 and the second DC bus BB D2 secondary side signal u D D , the bidirectional signal ports of the coordination control device CS are respectively connected to the bidirectional signal ports of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 , the third single-phase compensation device CD 3 and the energy storage device ES.

[0066] Optionally, the first single-phase compensation device CD 1 includes a first matching transformer MT cascaded in sequence 1 and a first single-phase AC-DC converter AD 1 , the second single-phase compensation device CD 2 includes a second matching transformer MT cascaded in sequence 2 and a second single-phase AC-DC converter AD 2 , the third single-phase compensation device CD 3 includes a third matching transformer MT cascaded in sequence​​​3 and the third single-phase AC-DC converter AD 3 .

[0067] Optionally, the energy storage device ES includes a DC-DC converter DD and an energy storage module SM connected in cascade. In this embodiment, the energy storage module SM can be any one or a combination of battery energy storage, supercapacitor energy storage, or flywheel energy storage.

[0068] Thus, in this embodiment, the single-phase compensation device and the energy storage device are comprehensively used to control the charge and discharge of the single-phase traction load and compensate the power quality. Each device is relatively independent in structure, with simple control and easy implementation. Among them, the three single-phase compensation devices are used both for charge and discharge power conversion and for power quality compensation, saving equipment investment; moreover, this embodiment adopts a system structure in which three single-phase compensation devices are connected in parallel with the energy storage device at the DC side, and the DC voltage is stable, which is beneficial to the realization of the control target.

[0069] Embodiment 2

[0070] As Figure 2 shown, this embodiment provides an energy storage in-phase power supply system based on a V-connected traction transformer. Among them, the energy storage in-phase power supply system includes a V-connected traction transformer TT for converting the external power supply provided by the three-phase power system into a voltage acceptable to the traction load, a standby V-connected traction transformer TB serving as a standby transformer for the V-connected traction transformer TT, a single-phase compensation device for charge and discharge power conversion and power quality compensation, an energy storage device ES for charge and discharge power conversion and energy storage or release, and a coordinated control device CS for detecting the operating parameters of the traction load and the energy storage device and controlling the operation of the single-phase compensation device and the energy storage device to achieve coordinated control of charge and discharge power conversion and power quality compensation.

[0071] The primary side of the V-connected traction transformer TT is connected to the three-phase power system PS, and the three terminals of the secondary side of the V-connected traction transformer TT are connected to the first traction bus BB T1 , the second traction bus BB T2 and the grounding electrode GD. A traction load TL is connected between the first traction bus BB T1 and the grounding electrode GD. Among them, the traction load TL is the total load exhibited by the traction network and the trains connected thereto in the case of the direct power supply mode, the direct power supply mode with a return line, or the BT power supply mode; the single-phase compensation device is the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 , and the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 and the third single-phase compensation device CD3 The AC terminals are respectively connected to three different ports on the secondary side of the V-connected traction transformer, and the positive poles of their DC terminals are connected in parallel and connected to the first DC bus BB D1 , and the negative poles of their DC terminals are connected in parallel and connected to the second DC bus BB D2 ; the positive pole of the energy storage device ES is connected to the first DC bus BB D1 , and its negative pole is connected to the second DC bus BB D2 ; the input terminals of the coordinated control device CS are respectively connected to the current transformer LH T1 connected in series with the first traction bus BB L secondary side signal i L , the AC terminal of the first single-phase compensation device CD 1 is connected to the current transformer LH T1 connected in series with the first traction bus BB 1 secondary side signal i CD1 , the AC terminal of the second single-phase compensation device CD 2 is connected to the current transformer LH 2 connected in series with the grounding electrode GD CD2 secondary side signal i 3 , the AC terminal of the third single-phase compensation device CD T2 is connected to the current transformer LH 3 connected in series with the second traction bus BB CD3 secondary side signal i D1 , the DC current sensor LH ES connected in series with the energy storage device ES by the first DC bus BB ES secondary side signal i T1 , and the voltage transformer YH T1 secondary side signal u T1 of the first traction bus BB T2 , the voltage transformer YH T2 secondary side signal u T2 of the second traction bus BB D1 , the DC voltage sensor YH D2 connected between the first DC bus BB D and the second DC bus BB D secondary side signal u 1 , the bidirectional signal ports of the coordinated control device CS are respectively connected to the first single-phase compensation device CD 2 , the second single-phase compensation device CD 3 , the third single-phase compensation device CD

[0072] The primary side of the standby V-connected traction transformer TB is connected to the three-phase power system PS, and any one of its secondary ports is connected to the traction load TL; three different ports on the secondary side of the standby V-connected traction transformer TB are also connected to the AC terminals of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 , and the third single-phase compensation device CD 3 .

[0073] Optionally, the first single-phase compensation device CD 1 includes a first matching transformer MT 1 and a first single-phase AC-DC converter AD 1 connected in series in sequence. The second single-phase compensation device CD 2 includes a second matching transformer MT 2 and a second single-phase AC-DC converter AD 2 connected in series in sequence. The third single-phase compensation device CD 3 includes a third matching transformer MT 3 and a third single-phase AC-DC converter AD 3 .

[0074] Optionally, the energy storage device ES includes a DC-DC converter DD and an energy storage module SM connected in series in sequence. In this embodiment, the energy storage module SM can be any one or any combination of battery energy storage, supercapacitor energy storage, or flywheel energy storage.

[0075] Thus, in addition to the functions of in-phase power supply, energy storage control, and power quality compensation, this embodiment also adopts a standby V-connected traction transformer TB, which can maintain the continuous operation and reliable power supply of the traction power supply system in the case of maintenance, repair, or failure of the V-connected traction transformer TT.

[0076] Embodiment 3

[0077] As Figure 3 shown, this embodiment provides an energy storage in-phase power supply system based on a V-connected traction transformer. Among them, the energy storage in-phase power supply system includes a V-connected traction transformer TT for converting the external power supply provided by the three-phase power system into a voltage acceptable to the AT power supply mode traction load, a single-phase compensation device for charge and discharge power conversion and power quality compensation, an energy storage device ES for charge and discharge power conversion and energy storage or release, and a coordinated control device CS for detecting the operating parameters of the traction load and the energy storage device and controlling the operation of the single-phase compensation device and the energy storage device to achieve coordinated control of charge and discharge power conversion and power quality compensation.

[0078] The primary side of the V-connected traction transformer TT is connected to the three-phase power system PS. Among the four terminals on its secondary side, three terminals present three-phase symmetrical voltages, and the fourth terminal presents two-phase symmetrical voltages with two of the three terminals. The two terminals and the fourth terminal are respectively connected to the first traction busbar BB according to the two-phase voltage symmetry relationship. T1 The grounding electrode GD and the first negative feeder busbar BB F The other terminal among the three terminals is connected to the second traction busbar BB T2 Between the first traction busbar BB T1 The grounding electrode GD and the first negative feeder busbar BB F A traction load TL is connected. Among them, the traction load TL is the total load presented by the traction network and the trains connected thereto in the case of the AT power supply mode.

[0079] The single-phase compensation device is the first single-phase compensation device CD 1 The second single-phase compensation device CD 2 And the third single-phase compensation device CD 3 The AC ends of the first single-phase compensation device CD 1 The second single-phase compensation device CD 2 And the third single-phase compensation device CD 3 Are respectively connected to three different ports of the three-phase symmetrical voltage terminals on the secondary side of the V-connected traction transformer. Their DC positive poles are mutually parallel and connected to the first DC busbar BB D1 Their DC negative poles are mutually parallel and connected to the second DC busbar BB D2 ; The positive pole of the energy storage device ES is connected to the first DC busbar BB D1 Its negative pole is connected to the second DC busbar BB D2 ; The input ends of the coordinated control device CS are respectively connected to the secondary side signals i T1 Of the current transformer LH L Connected in series with the traction load feeder by the first traction busbar BB L The secondary side signals i F Of the current transformer LH F Connected in series with the traction load negative feeder by the first negative feeder busbar BB F The secondary side signals i 1 Of the current transformer LH T1 Connected in series with the AC end of the first single-phase compensation device CD by the first traction busbar BB 1 The secondary side signals i CD1 The secondary side signals i 2 Of the current transformer LH 2 Connected in series with the AC end of the second single-phase compensation device CD by the grounding electrode GD CD2 The secondary side signals i 3The AC terminal is connected to the second traction busbar BB T2 by the series-connected current transformer LH 3 for the secondary side signal i CD3 ; the energy storage device ES is connected to the first DC busbar BB D1 by the series-connected DC current sensor LH ES for the secondary side signal i ES , and the voltage transformer YH T1 of the first traction busbar BB T1 for the secondary side signal u T1 , the voltage transformer YH T2 of the second traction busbar BB T2 for the secondary side signal u T2 , the voltage transformer YH F of the first negative feeder busbar BB F for the secondary side signal u F , the DC voltage sensor YH D1 connected between the first DC busbar BB D2 and the second DC busbar BB D for the secondary side signal u D , and the two-way signal ports of the coordination control device CS are respectively connected to the two-way signal ports of the first single-phase compensation device CD 1 , the second single-phase compensation device CD 2 , the third single-phase compensation device CD 3 and the energy storage device ES.

[0080] Optionally, the first single-phase compensation device CD 1 includes a first matching transformer MT 1 and a first single-phase AC-DC converter AD 1 connected in cascade, the second single-phase compensation device CD 2 includes a second matching transformer MT 2 and a second single-phase AC-DC converter AD 2 connected in cascade, and the third single-phase compensation device CD 3 includes a third matching transformer MT 3 and a third single-phase AC-DC converter AD 3 .

[0081] Optionally, the energy storage device ES includes a DC-DC converter DD and an energy storage module SM connected in cascade. In this embodiment, the energy storage module SM can be any one or any combination of battery energy storage, supercapacitor energy storage or flywheel energy storage.

[0082] The definitions of electrical quantities for the traction load in this embodiment are as follows:

[0083] The feeder current transformer LH of the traction load TLL Secondary side signal i L The polarity is defined as flowing from the first traction bus bar BB T1 into the traction load TL is positive, and the negative feeder current transformer LH F Secondary side signal i F The polarity is defined as flowing from the first negative feeder bus bar BB F into the traction load TL is positive, and the first traction bus bar BB T1 voltage transformer YH T1 Secondary side signal u T1 The polarity is defined as the corresponding end of the first traction bus bar BB T1 is positive, the corresponding end of the grounding electrode GD is negative, and the first negative feeder bus bar BB F voltage transformer YH F Secondary side signal u F The polarity is defined as the corresponding end of the first negative feeder bus bar BB F is positive, the corresponding end of the grounding electrode GD is negative, and from the signal u T1 and the signal i L 、the signal u F and the signal i F can be respectively calculated and superimposed to obtain the active power P absorbed by the traction load TL in the AT power supply mode L 、reactive power Q L and harmonic current i Lh 。

[0084] Thus, this embodiment is applicable to the single-phase power supply, energy storage control and power quality compensation of the V-connected traction substation in the AT power supply mode, expands the applicable range of the technical solution of the present invention, and ensures the non-phase-separated power supply and economic operation of high-speed railways and heavy-haul railways.

[0085] Embodiment 4

[0086] As Figure 4 shown, this embodiment provides a control method for an energy storage single-phase power supply system based on a V-connected traction transformer, wherein the specific steps of the control method include:

[0087] Step 1. System initialization: The coordinated control device CS executes the definition of electrical quantities;

[0088] Step 2. Charge and discharge power calculation: The coordinated control device CS first calculates the active power and reactive power currently absorbed by the traction load TL, and detects the current state of charge SOC of the energy storage device ES through the bidirectional signal between the coordinated control device CS and the energy storage device ES ES ,and then performs the energy storage device ES and the first single-phase compensation device CD 1 、the second single-phase compensation device CD 2 and the third single-phase compensation device CD3 Determination of charge and discharge power;

[0089] Step 3: Calculation of power quality compensation power: The coordination control device CS determines the power quality compensation power of the first single-phase compensation device CD, 1 the second single-phase compensation device CD, 2 and the third single-phase compensation device CD 3 according to the calculated value of the charge and discharge power;

[0090] Step 4: The coordination control device CS generates the combined output current of the energy storage device ES and the first single-phase compensation device CD, 1 the second single-phase compensation device CD, 2 and the third single-phase compensation device CD 3 respectively controls the above devices to output current, and returns to Step 2 to execute in a loop after a preset time step △t.

[0091] In this embodiment, the specific method for defining electrical quantities in Step 1 is as follows:

[0092] The secondary side signal i of the feeder current transformer LH of the traction load TL L is defined such that the current flowing from the first traction bus BB L into the traction load TL is positive, and the secondary side signal u of the voltage transformer YH T1 of the first traction bus BB T1 is defined such that the corresponding end of the first traction bus BB is positive and the corresponding end of the grounding electrode GD is negative. Based on the secondary side signal u of the voltage transformer YH T1 of the first traction bus BB T1 and the secondary side signal i of the feeder current transformer LH of the traction load TL T1 the active power P absorbed by the traction load TL, T1 reactive power Q, T1 and harmonic current i T1 are calculated; The secondary side signal u of the voltage transformer YH L of the second traction bus BB L is defined such that the corresponding end of the second traction bus BB is positive and the corresponding end of the grounding electrode GD is negative; L The secondary side signal of the current transformer at the AC end of the first single-phase compensation device CD L connected to the first traction bus BB together with the traction load TL Lh is defined as i T2 T2 T2 T2 T1 1 CD1

[0093] ​​​​​​​, the polarity is defined as flowing from the first traction busbar BB T1 into the first single-phase compensation device CD 1 is positive. Based on the voltage transformer YH T1 of the first traction busbar BB T1 secondary side signal u T1 and the first single-phase compensation device CD 1 secondary side signal i of the AC terminal current transformer CD1 calculate the active power P 1 absorbed by the AC terminal of the first single-phase compensation device CD 1 and the reactive power Q 1 ;

[0094] The second single-phase compensation device CD connected between the second traction busbar BB T2 and the grounding electrode GD 2 The secondary side signal of the AC terminal current transformer is defined as i CD2 , and the polarity is defined as flowing from the grounding electrode GD into the second single-phase compensation device CD 2 is positive. Based on the secondary side signal i 2 of the AC terminal current transformer of the second single-phase compensation device CD CD2 and the second traction busbar BB T2 voltage transformer YH T2 secondary side signal u T2 The reverse signal of calculates the active power P 2 absorbed by the AC terminal of the second single-phase compensation device CD 2 and the reactive power Q 2 ;

[0095] The third single-phase compensation device CD connected between the first traction busbar BB T1 and the second traction busbar BB T2 The secondary side signal of the AC terminal current transformer is defined as i 3 , and the polarity is defined as the same as that flowing from the second traction busbar BB CD3 into the third single-phase compensation device CD T2 is positive. Based on the secondary side signal i 3 of the AC terminal current transformer of the third single-phase compensation device CD 3 and the second traction busbar BB CD3 voltage transformer YH T2 secondary side signal u T2 and the voltage transformer YH T2 of the first traction busbar BB T1 secondary side signal u T1 The difference of calculates the active power P T1 absorbed by the AC terminal of the third single-phase compensation device CD 3 and the reactive power Q 3 and the reactive power Q3 ;

[0096] DC side current sensor LH of energy storage device ES ES Secondary side signal i ES The polarity is defined as flowing into the first DC bus BB D1 is positive, DC side voltage sensor YH D Secondary side signal u D The polarity is defined as the corresponding end of the first DC bus BB D1 is positive, and the corresponding end of the second DC bus BB D2 is negative. Based on the secondary side signal i of the DC side current sensor LH of the energy storage device ES ES and the DC voltage sensor YH ES Secondary side signal u D Calculate the active power P released by the energy storage device ES D . ES .

[0097] As Figure 5 shown, the specific method for determining the charge and discharge power in step 2 of this embodiment is as follows:

[0098] Update the sampling signals at all input terminals of the coordination control device CS, and use the voltage transformer YH of the first traction bus BB T1 Secondary side signal u T1 and the feeder current transformer LH of the traction load TL T1 Secondary side signal i L Calculate the active power P L , reactive power Q L absorbed by the traction load TL L and harmonic current i Lh ;

[0099] Statistically analyze the historical operating conditions of the traction load TL to obtain the historical average active power P within a preset time length before the current moment Lav ; If there is no historical data of the traction load, set the initial value of the historical average active power P Lav to zero, and start to statistically analyze and calculate the average active power of the traction load after starting;

[0100] If the current state of charge SOC of the energy storage device ES ES is greater than its allowable lower limit of state of charge SOC min and less than its allowable upper limit of state of charge SOC max , where 0 < SOC min < SOC max < 1, then perform charge and discharge control: the target value of the discharge power of the energy storage device ES is P ES *= PL -P Lav the first single-phase compensation device CD 1 the target value of the active power absorbed by the AC terminal is P 1 * = P Lav / 3 - P L the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 the target values of the active power absorbed by the AC terminals all take P 2 * = P 3 * = P Lav / 3;

[0101] If the current state of charge SOC of the energy storage device ES ES is less than or equal to the lower limit SOC of its allowable state of charge min then perform the control for restoring the discharged energy of the energy storage device ES and output an alarm prompt: the target value of the discharge power of the energy storage device ES is P ES * = -P RS where P RS is the restoration power of the energy storage device, which is a preset value, and its value is greater than zero and less than the absolute value of the historical average active power P Lav Generally, take |P Lav | / 10, the first single-phase compensation device CD 1 the target value of the active power absorbed by the AC terminal is P 1 * = P RS the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 the target values of the active power absorbed by the AC terminals all take P 2 * = P 3 * = 0;

[0102] If the current state of charge SOC of the energy storage device ES ES is greater than or equal to the upper limit SOC of its allowable state of charge max then perform the control for restoring the excessive energy of the energy storage device ES and output an alarm prompt: the target value of the discharge power of the energy storage device ES is P ES * = P RS the first single-phase compensation device CD 1 the target value of the active power absorbed by the AC terminal is P 1 * = -P RS the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 the target values of the active power absorbed by the AC terminals all take P 2 * = P 3 * = 0.

[0103] In an embodiment, the coordination control device CS periodically collects the traction bus voltage (u T1 ), and the traction load current (TL), and calculates the current active power P L , reactive power Q L , and harmonic current i Lh . At the same time, the system calculates the historical average active power PLav, and determines the current state according to the state of charge (SOC ES ) of the energy storage device:

[0104] Normal range (SOC min <SOC ES <SOC max ): The system performs dynamic energy balance control, enabling the energy storage device to output power P ES * = P L -P Lav , reducing load fluctuations; three single-phase compensation devices cooperate to achieve power balance;

[0105] Discharged range (SOC ES ≤SOC min ): Start discharged protection control. The energy storage does not bear load regulation temporarily. Only CD 1 outputs a small amount of fixed power P RS , avoiding further decrease of SOC, and issuing an alarm at the same time;

[0106] Overcharged range (SOC ES ≥SOC max ): Start overcharged treatment control, forcing the energy storage to absorb a small amount of power P RS , releasing part of the energy and absorbing an equal amount of power through CD 1 to maintain the bus power balance, and giving an alarm reminder at the same time.

[0107] The solution of the present invention realizes flexible response of the system in three states of normal, discharged, and overcharged by calculating the traction load power and energy storage state in real time, dynamically regulating the output power of the energy storage device and the compensation device, ensuring the stable operation of the power supply system, reducing the bus power fluctuation, improving the energy storage utilization rate at the same time, and ensuring the safe and efficient operation of the system.

[0108] As Figure 6 shown, the specific method for determining the power quality compensation power in step three of this embodiment includes the following:

[0109] Perform reactive power control: The target value Q 1 * of the reactive power absorbed by the AC terminal of the first single-phase compensation device CD 1 satisfies the reactive power Q L absorbed by the traction load TL;

[0110] Perform harmonic current control: The first single-phase compensation device CD1 Target value of harmonic current absorbed by the AC terminal, i 1h *Satisfy the harmonic current i absorbed by the traction load TL Lh ;

[0111] Perform negative sequence power control: If the current state of charge SOC of the energy storage device ES ES is greater than the lower limit SOC of its allowable state of charge min and less than the upper limit SOC of its allowable state of charge max , then no negative sequence power control is performed: The target values of reactive power absorbed by the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 at the AC terminal are both taken as zero;

[0112] If the current state of charge SOC of the energy storage device ES ES is less than or equal to the lower limit SOC of its allowable state of charge min , or the SOC ES is greater than or equal to the upper limit SOC of its allowable state of charge max , then further judgment is required. The rules for further judgment are:

[0113] The allowable value of single-phase power reduced to the secondary side of the V-connected traction transformer TT according to the three-phase power system PS and the preset standard of three-phase voltage unbalance in power quality is represented by S AN , where S AN ≥0. If data is lacking and reduction is impossible, the allowable value of single-phase power S AN adopts a preset value; When the modulus |P L | of the active power P currently absorbed by the traction load TL L is less than or equal to the allowable value of single-phase power S AN , then no negative sequence power control is performed, and the target values of reactive power absorbed by the second single-phase compensation device CD 2 and the third single-phase compensation device CD 3 at the AC terminal are both taken as zero; If the modulus |P L | is greater than the allowable value of single-phase power S AN , then negative sequence power control is performed, and further judgment is required. The rules for further judgment are:

[0114] If P L >0, then the target value of reactive power absorbed by the second single-phase compensation device CD 2 at the AC terminal is taken as Q 2 *=(S AN -P L ) / , and the target value of reactive power absorbed by the third single-phase compensation device CD 3 at the AC terminal is taken as Q 3* = (P L - S AN ) / ; If P L < 0, then the target reactive power absorbed by the second single - phase compensation device CD 2 is taken as Q 2 * = -(P L + S AN ) / , and the target reactive power absorbed by the third single - phase compensation device CD 3 is taken as Q 3 * = (P L + S AN ) / .

[0115] Thereby, the system structure and control method of this embodiment can effectively control the power quality in the normal, power - deficit, and over - charged states of the energy storage device, with high operation flexibility and strong adaptability, ensuring that the power quality of the traction substation meets the national standards, which is beneficial to the safe and reliable operation of the railway and power systems.

[0116] As Figure 7 shown, the specific method for generating the comprehensive output current in step four of this embodiment includes the following:[

[0117] The coordination control device CS detects the secondary - side signal u T1 of the voltage transformer YH T1 of the first traction bus BB T1 and the secondary - side signal u T2 of the voltage transformer YH T2 of the second traction bus BB T2 . If the fundamental voltage phase of the secondary - side signal u T1 of the voltage transformer YH T1 of the first traction bus BB T1 leads the fundamental voltage phase of the secondary - side signal u T2 of the voltage transformer YH T2 of the second traction bus BB T2 , then the target active power P 2 absorbed by the AC terminal of the second single - phase compensation device CD 2 * is interchanged with the target active power P 3 absorbed by the AC terminal of the third single - phase compensation device CD 3 *, and the target reactive power Q 2 absorbed by the AC terminal of the second single - phase compensation device CD 2 * is interchanged with the target reactive power Q 3 absorbed by the AC terminal of the third single - phase compensation device CD 3 *;

[0118] According to the first single-phase compensation device CD 1 The target value of the active power P absorbed by the AC terminal 1 *, the target value of the reactive power Q 1 *, the target value of the harmonic current i 1h * and its port voltage signal u T1 , the target value of the port current signal i of the first single-phase compensation device CD is obtained 1 *; According to the second single-phase compensation device CD CD1 The target value of the active power P absorbed by the AC terminal 2 *, the target value of the reactive power Q 2 * and its port voltage signal (-u 2 ) T2 , the target value of the port current signal i of the second single-phase compensation device CD is obtained 2 *; According to the third single-phase compensation device CD CD2 The target value of the active power P absorbed by the AC terminal 3 *, the target value of the reactive power Q 3 * and its port voltage signal (u 3 -u T2 ) T1 , the target value of the port current signal i of the third single-phase compensation device CD is obtained 3 *; According to the target value of the active power P released by the DC terminal of the energy storage device ES CD3 * and its port voltage signal u ES *, the target value of the port current signal i of the energy storage device ES is obtained D * ES .

[0119] In the embodiment of the present invention, the coordination control device CS will compare the fundamental voltage phasors (u T1 ) on the first traction bus (BB T2 ) and the second traction bus (BB T1 u T2 ) in real time to judge the phase sequence relationship:

[0120] If the phase of u T1 leads that of u T2 : To ensure the system balance and reasonable power transmission direction, automatically exchange the active / reactive power target values of CD 2 and CD 3 (the exchange of P 2 * and P 3 *, Q 2 * and Q 3 *).

[0121] Then, the system calculates the target current signals (i of each compensation device and the energy storage device according to the target power values of each device and the corresponding port voltage signalsCD1 *, i CD2 *, i CD3 *, i ES *), so as to accurately control the output subsequently and achieve the combined regulation of active power, reactive power, and harmonics.

[0122] This control strategy flexibly adjusts the power distribution scheme of each compensation device by dynamically discriminating the phase of the fundamental wave voltage phasor of the traction busbar. At the same time, based on each power target value and the real-time voltage signal, it generates the port current command to achieve the accurate control of multiple compensation targets (active power, reactive power, harmonics), enhances the system adaptability and real-time performance, and ensures the power supply stability and power quality.

[0123] Thereby, the control method of this embodiment realizes the integrated control of system charge and discharge, in-phase power supply, and power quality. During charge and discharge, it cancels the split phase, conducts negative sequence control, reactive power compensation, and harmonic suppression, which is beneficial to the continuous and reliable electrified operation of the train. It also realizes the decoupled control of active and reactive power of the single-phase compensation device, and the control method is simple and efficient.

[0124] The present invention also provides a computer-readable storage medium, on which instructions are stored. When running on a computer, the computer is made to execute the above-mentioned control method of the energy storage in-phase power supply system based on the V-connected traction transformer.

[0125] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An energy storage co-phase power supply system based on a V-connected traction transformer, characterized in that: The energy storage co-phase power supply system comprises: The V-connected traction transformer TT is used to transform the external power supply on the primary side to the traction bus on the secondary side. The primary side of the V-connected traction transformer TT is connected to the three-phase power system PS. The three terminals of the secondary side of the V-connected traction transformer TT are connected to the first traction bus BB one by one. T1 , the second traction bus BB T2 and grounding electrode GD, on the first traction bus BB T1 A traction load TL is connected between the grounding electrode GD; The single-phase compensation device is used for charging and discharging power conversion and power quality compensation, including a first single-phase compensation device CD1, a second single-phase compensation device CD2 and a third single-phase compensation device CD3; Energy storage device ES, used for charging and discharging power conversion and energy storage or release, the positive electrode of the energy storage device ES is connected to the first DC bus BB D1 , the negative pole is connected to the second DC bus BB D2 ; The coordination control device CS is used to detect the operating parameters of the traction load and the energy storage device ES, and control the operation of the single-phase compensation device and the energy storage device ES to achieve charging and discharging power conversion and power quality compensation; the input end of the coordination control device CS is connected to the following signals: The traction load feeder is composed of the first traction bus BB T1 The current transformer LH connected in series L Secondary side signal i L , the AC end of the first single-phase compensation device CD1 is connected to the first traction bus BB T1 The secondary side signal i of the series connected current transformer LH1 CD1 , the AC end of the second single-phase compensation device CD2 is connected in series with the grounding electrode GD by the current transformer LH2 secondary side signal i CD2 The AC end of the third single-phase compensation device CD3 is connected to the second traction bus BB T2 The secondary side signal i of the series connected current transformer LH3 CD3 , the energy storage device ES is connected to the first DC bus BB D1 The DC current sensor LH connected in series ES Secondary side signal i ES , and the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 , the second traction bus BB T2 Voltage transformer YH T2 Secondary side signal u T2 , connected to the first DC bus BB D1 and the second DC bus BB D2 DC voltage sensor YH D Secondary side signal u D ; The bidirectional signal port of the coordination control device CS is respectively connected to the bidirectional signal ports of the first single-phase compensation device CD1, the second single-phase compensation device CD2, the third single-phase compensation device CD3 and the energy storage device ES.

2. According to claim 1, a V-connected traction transformer-based energy storage co-phase power supply system is characterized in that: The AC ends of the first single-phase compensation device CD1, the second single-phase compensation device CD2 and the third single-phase compensation device CD3 are respectively connected to three different ports of the secondary side of the V-connected traction transformer TT, and the positive poles of their DC ends are connected in parallel and connected to the first DC bus BB. D1 , the negative poles of their DC terminals are connected in parallel and connected to the second DC bus BB D2 ; The first single-phase compensation device CD1 includes a first matching transformer MT1 and a first single-phase AC-DC converter AD1 which are cascaded in sequence, the second single-phase compensation device CD2 includes a second matching transformer MT2 and a second single-phase AC-DC converter AD2 which are cascaded in sequence, and the third single-phase compensation device CD3 includes a third matching transformer MT3 and a third single-phase AC-DC converter AD3 which are cascaded in sequence.

3. The energy storage co-phase power supply system based on V-connected traction transformer according to claim 1 is characterized in that: The energy storage device ES includes a DC-DC converter DD and an energy storage module SM which are cascaded in sequence.

4. The energy storage co-phase power supply system based on V-connected traction transformer according to claim 1 is characterized in that: The energy storage co-phase power supply system also includes a standby V-connected traction transformer TB used as a standby transformer for the V-connected traction transformer TT. The primary side of the standby V-connected traction transformer TB is connected to the three-phase power system PS, and any one port of the secondary side of the standby V-connected traction transformer TB is connected to the traction load TL; the three different ports of the secondary side of the standby V-connected traction transformer TB are also connected one by one to the AC ends of the first single-phase compensation device CD1, the second single-phase compensation device CD2 and the third single-phase compensation device CD3.

5. A control method for a V-connected traction transformer-based energy storage co-phase power supply system, characterized in that: The control method is applied to the energy storage co-phase power supply system based on the V-connected traction transformer according to any one of claims 1 to 4, and is characterized in that the specific steps of the control method include: Step 1: System initialization: The coordination control device CS executes the definition of electrical quantities; Step 2: Calculation of charging and discharging power: The coordination control device CS first calculates the active power and reactive power currently absorbed by the traction load TL, and detects the current state of charge SOC of the energy storage device ES through the bidirectional signal between the coordination control device CS and the energy storage device ES. ES , and then determine the charge and discharge power of the energy storage device ES and the first single-phase compensation device CD1, the second single-phase compensation device CD2 and the third single-phase compensation device CD3; Step 3: Calculation of power quality compensation power: The coordination control device CS determines the power quality compensation power of the first single-phase compensation device CD1, the second single-phase compensation device CD2 and the third single-phase compensation device CD3 according to the calculated value of the charge and discharge power; Step 4: The coordination control device CS generates the comprehensive output current of the energy storage device ES and the first single-phase compensation device CD1, the second single-phase compensation device CD2 and the third single-phase compensation device CD3, and controls the above devices to output current respectively. After a preset time step △t, it returns to step 2 and executes in a loop.

6. A method for controlling an energy storage co-phase power supply system based on a V-connected traction transformer according to claim 5, characterized in that: The specific method for defining electrical quantities in step 1 is as follows: Feeder current transformer LH for traction load TL L Secondary side signal i L The polarity is determined by the first traction bus BB T1 The traction load TL flowing into the first traction bus BB is positive. T1 Voltage transformer YH T1 Secondary side signal u T1 Polarity is set to the first traction bus BB T1 The corresponding end of is positive, and the corresponding end of the grounding electrode GD is negative. Based on the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 and the feeder current transformer LH of the traction load TL L Secondary side signal i L Calculate the active power P absorbed by the traction load TL L , reactive power Q L and harmonic current i Lh ; Second traction bus BB T2 Voltage transformer YH T2 Secondary side signal u T2 The polarity is set to the second traction bus BB T2 The corresponding end of is positive, and the corresponding end of the ground electrode GD is negative; Connected to the first traction bus BB together with the traction load TL T1 The secondary side signal of the current transformer at the AC end of the first single-phase compensation device CD1 is set to i CD1 , the polarity is determined by the first traction bus BB T1 The current flowing into the first single-phase compensation device CD1 is positive, based on the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 and the secondary side signal i of the current transformer at the AC end of the first single-phase compensation device CD1 CD1 The active power P1 and reactive power Q1 absorbed by the AC end of the first single-phase compensation device CD1 are calculated; Connected to the second traction bus BB T2 The secondary side signal of the current transformer at the AC end of the second single-phase compensation device CD2 between the grounding electrode GD is set to i CD2 The polarity is set as positive from the grounding electrode GD into the second single-phase compensation device CD2, based on the secondary side signal i of the current transformer at the AC end of the second single-phase compensation device CD2 CD2 and the second traction bus BB T2 Voltage transformer YH T2 Secondary side signal u T2 The active power P2 and reactive power Q2 absorbed by the AC end of the second single-phase compensation device CD2 are calculated by using the inverted signal; Connected to the first traction bus BB T1 and the second traction bus BB T2 The secondary side signal of the AC current transformer of the third single-phase compensation device CD3 is set to i CD3 , the polarity is determined to be the same as that of the second traction bus BB T2 The current flowing into the third single-phase compensation device CD3 is positive, based on the secondary side signal i of the current transformer at the AC end of the third single-phase compensation device CD3 CD3 and the second traction bus BB T2 Voltage transformer YH T2 Secondary side signal u T2 With the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 The difference is calculated to obtain the active power P3 and reactive power Q3 absorbed by the AC end of the third single-phase compensation device CD3; Energy storage device ES DC end current sensor LH ES Secondary side signal i ES The polarity is set to flow into the first DC bus BB D1 is positive, DC terminal voltage sensor YH D Secondary side signal u D The polarity is set to the first DC bus BB D1 The corresponding end is positive, the second DC bus BB D2 The corresponding end is negative, based on the DC end current sensor LH of the energy storage device ES ES Secondary side signal i ES And DC voltage sensor YH D Secondary side signal u D Calculate the active power P released by the energy storage device ES ES .

7. The control method of a V-connected traction transformer-based energy storage co-phase power supply system according to claim 5 is characterized in that: The specific method for determining the charge and discharge power in step 2 is as follows: Update the sampling signals of all input terminals of the coordination control device CS, and the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 and the feeder current transformer LH of the traction load TL L Secondary side signal i L Calculate the active power P absorbed by the traction load TL L , reactive power Q L and harmonic current i Lh ; The historical operation status of the traction load TL is counted to obtain the historical average active power P within the preset time length before the current moment. Lav If there is no historical data of traction load, the historical average active power P Lav The initial value is set to zero, and the average active power of the traction load is counted and calculated after the operation starts; If the current state of charge SOC of the energy storage device ES ES Greater than the lower limit of the allowed state of charge SOC min And it is less than the upper limit of the state of charge SOC max , where 0 <SOC min <SOC max <1, then charge and discharge control is performed: the target discharge power value of the energy storage device ES is P ES *=P L -P Lav , the active power target value P1*=P absorbed by the AC end of the first single-phase compensation device CD1 Lav / 3-P L The target values ​​of active power absorbed by the AC end of the second single-phase compensation device CD2 and the third single-phase compensation device CD3 are both P2*=P3*=P Lav / 3; If the current state of charge SOC of the energy storage device ES ES Less than or equal to the lower limit of the allowed state of charge SOC min , the energy storage device ES power recovery control is performed and an alarm prompt is output: the target value of the energy storage device ES discharge power is P ES *=-P RS , where P RS The energy storage device restores power, which is a preset value, and its value is greater than zero and less than the historical average active power P Lav The absolute value of the active power target value P1*=P absorbed by the AC end of the first single-phase compensation device CD1 RS , the target values ​​of active power absorbed by the AC ends of the second single-phase compensation device CD2 and the third single-phase compensation device CD3 are both P2*=P3*=0; If the current state of charge SOC of the energy storage device ES ES Greater than or equal to the upper limit of the state of charge SOC max , the energy storage device overflow recovery control is performed and an alarm prompt is output: the target value of the energy storage device ES discharge power is P ES *=P RS , the active power target value absorbed by the AC end of the first single-phase compensation device CD1 is P1*=-P RS The target values ​​of active power absorbed by the AC ends of the second single-phase compensation device CD2 and the third single-phase compensation device CD3 are both P2*=P3*=0.

8. The method for controlling an energy storage co-phase power supply system based on a V-connected traction transformer according to claim 5 is characterized in that: The specific method for determining the power quality compensation power in step 3 is as follows: Reactive power control: The reactive power target value Q1* absorbed by the AC end of the first single-phase compensation device CD1 meets the reactive power Q absorbed by the traction load TL L ; Harmonic current control: The harmonic current target value i absorbed by the AC end of the first single-phase compensation device CD1 1h *Meet the harmonic current i absorbed by the traction load TL Lh ; Perform negative sequence power control: If the current state of charge SOC of the energy storage device ES ES Greater than the lower limit of the allowed state of charge SOC min And it is less than the upper limit of the state of charge SOC allowed max , then no negative sequence power control is performed: the reactive power target values ​​absorbed by the AC ends of the second single-phase compensation device CD2 and the third single-phase compensation device CD3 are both zero; If the current state of charge SOC of the energy storage device ES ES Less than or equal to the lower limit of the allowed state of charge SOC min , or the SOC ES Greater than or equal to the upper limit of the state of charge SOC max , further judgment is needed, and the rules for further judgment are: According to the three-phase power system PS and the preset standard of power quality three-phase voltage unbalance, the single-phase power allowable value of the secondary side of the traction transformer TT connected to V is calculated by S AN Indicates that S AN ≥0, if the data is insufficient and cannot be calculated, the single-phase power allowable value S AN Use the preset value; when the active power P currently absorbed by the traction load TL L The modulus value of |P L |Less than or equal to the single-phase power allowable value S AN , then no negative sequence power control is performed, and the reactive power target values ​​absorbed by the AC ends of the second single-phase compensation device CD2 and the third single-phase compensation device CD3 are both zero; if the module value |P L |Greater than the single-phase power allowable value S AN , then negative sequence power control is performed, and further judgment is made. The rules for further judgment are: If P L >0, then the reactive power target value absorbed by the AC end of the second single-phase compensation device CD2 is Q2*=(S AN -P L ) / The reactive power target value absorbed by the AC end of the third single-phase compensation device CD3 is Q3*=(P L -S AN ) / If P L <0, then the reactive power target value absorbed by the AC end of the second single-phase compensation device CD2 is Q2*=-(P L +S AN ) / The reactive power target value absorbed by the AC end of the third single-phase compensation device CD3 is Q3*=(P L +S AN ) / .

9. The method for controlling an energy storage co-phase power supply system based on a V-connected traction transformer according to claim 5, characterized in that: The specific method for generating the comprehensive output current in step 4 is as follows: The coordination control device CS detects the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 and the second traction bus BB T2 Voltage transformer YH T2 Secondary side signal u T2 The fundamental voltage phasor of the first traction bus BB T1 Voltage transformer YH T1 Secondary side signal u T1 The fundamental voltage phase is ahead of the second traction bus BB T2 Voltage transformer YH T2 Secondary side signal u T2 The fundamental voltage phase of the second single-phase compensation device CD2 is replaced by the active power target value P2* absorbed by the AC end of the second single-phase compensation device CD2 and the active power target value P3* absorbed by the AC end of the third single-phase compensation device CD3, and the reactive power target value Q2* absorbed by the AC end of the second single-phase compensation device CD2 and the reactive power target value Q3* absorbed by the AC end of the third single-phase compensation device CD3 are replaced; According to the active power target value P1*, reactive power target value Q1*, harmonic current target value i1 absorbed by the AC end of the first single-phase compensation device CD1, 1h * and its port voltage signal u T1 , get the target value i of the current signal at the port of the first single-phase compensation device CD1 CD1 *; According to the active power target value P2*, reactive power target value Q2* and its port voltage signal (-u T2 ), and obtain the target value i of the current signal at the port of the second single-phase compensation device CD2 CD2 *; According to the active power target value P3*, reactive power target value Q3* and its port voltage signal (u T2 -u T1 ), and obtain the target value i of the current signal at the port of the third single-phase compensation device CD3 CD3 *; According to the active power target value P released by the DC terminal of the energy storage device ES ES * and its port voltage signal u D , get the target value i of the current signal at the ES port of the energy storage device ES *.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, which, when executed on a computer, enable the computer to execute the energy storage co-phase power supply system control method based on a V-connected traction transformer as described in any one of claims 5 to 9.

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