An all-through three-phase traction power supply system simulation device and a control method thereof

Abstract

The application provides a full-through three-phase traction power supply system simulation device, which comprises n three-phase AC-DC converters simulating n trains, n three-phase transformers, a three-phase universal AC-DC converter AD, a three-phase bus TPB and a measurement and control device MC; the AC ports of the three-phase AC-DC converters are connected with the three-phase bus TPB through the three-phase transformers respectively, the AC port of the three-phase universal AC-DC converter AD is connected with the three-phase bus TPB, and the measurement and control device MC controls the operation of the n three-phase AC-DC converters and the three-phase universal AC-DC converter AD. The bidirectional controllability of the AC-DC converter can be used to simulate the train by the three-phase AC-DC converter, and the measurement and control device can control the three-phase AC-DC converter to simulate the train running in the traction, regeneration, inertia or parking working conditions and the train load or tonnage size.

Description

Technical Field

[0001] This invention relates to the field of traction power supply circuit design for electrified railways, and particularly to a simulation device and control method for a fully continuous three-phase traction power supply system. Background Technology

[0002] Under the same power supply capacity, three-phase generators, motors, transformers, and transmission lines are more material-efficient to manufacture and construct than single-phase components, and their simpler structure and superior performance, coupled with the constant instantaneous power of three-phase electricity, have led to the widespread industrial application of three-phase AC power. The earliest ideal trams attempted three-phase power supply; however, due to numerous technical challenges such as structural issues, reliability problems, and the need for turnouts, the practicality of this method for mainline railways was severely challenged, and it was gradually replaced by low-voltage DC and 25kV single-phase AC power supply systems. In the 25kV single-phase AC power supply system, to reduce the imbalance of single-phase train loads on the three-phase power grid, phase commutation connections or power quality management devices are usually required to address negative sequence. The advantages of three-phase AC power have not been fully realized in railway traction power supply. Therefore, the applicant's research team proposed a three-phase traction power supply system.

[0003] The train's operation, including its position on the traction network and its operating conditions, is dynamic and time-varying, thus causing the entire network to be time-varying. Train operating conditions include traction, coasting, and regenerative braking. The fundamental purpose of studying the traction load process and its network voltage changes is to study and simulate the train's operation.

[0004] Corresponding to single-phase power supply systems, existing trains are all single-phase trains, and dynamic simulation of the operation process of three-phase trains has not yet been addressed. From published articles and patents, it can be seen that existing single-phase train operation simulations partially employ impedance simulation of multiple trains operating simultaneously. However, this model only covers a single train operating condition and cannot simulate regenerative braking, coasting, or combined multi-train operating conditions, nor can it achieve dynamic simulation of the train operation process. Furthermore, most studies focus on the dynamic simulation of train operation in urban rail transit, primarily subways, and often treat the train as a controlled current source or converter. However, urban rail transit uses a DC power supply system, and its traction network power supply mode is fundamentally different from the AC power supply system used in mainline electrified railways. Moreover, it lacks control over multiple train combinations, making it impossible to continuously adjust the power of each train individually, and it cannot simulate the energy feedback operation of a three-phase traction power supply system and a three-phase train. Additionally, the simulation of train operation in urban rail transit systems uses software to perform train traction calculations and plot train characteristic curves to study the characteristics of urban rail transit systems. Using software to simulate train operating states requires a large amount of historical data to support the calculation results and is not suitable for on-site experimental testing.

[0005] For real-time simulation of AC railway train operating conditions, patent CN109936135A provides an electrified railway in-phase energy storage power supply structure and its control method. It uses the secondary side In1 of the load feeder current transformer and the secondary side Un2 of the load bus voltage transformer to detect the traction load operating conditions and traction load size. When the detected traction load is operating in regenerative braking condition, it controls n sets of energy storage compensation devices ECn to charge. When the power is greater than 0, it is in traction state, and when the power is less than 0, it is in regenerative braking state. However, its focus is on the balance between the charging and discharging of the energy storage device and the overall train operating conditions. It does not involve the continuous control model of multiple trains and their power, nor does it involve the simulation of multi-train combined operating conditions, nor does it involve the three-phase-three-phase-three-phase internal feedback operation mode, negative sequence, or reactive power compensation.

[0006] Therefore, based on the three-phase traction power supply system, a multi-train operation simulation device suitable for the three-phase traction power supply system is proposed. Summary of the Invention

[0007] This invention proposes a fully continuous three-phase traction power supply system simulation device and its control method, which can effectively solve the following technical problems: (1) simulation of multiple three-phase train loads; (2) self-circulation and internal feedback of three-phase power grid-three-phase train-three-phase power grid, simulation of active power of three-phase trains in traction network, and simulation of energy feedback between three-phase train load and external power source; (3) the instantaneous active power of the system is kept constant, the energy consumption caused by the test process is small, and energy saving and environmental protection are achieved; (4) real-time simulation of the traction load process of multiple trains running under different loads and different working conditions, and the power of each train can be continuously adjusted under the rated power limit; (5) the traction network is connected in phase; (6) the system is three-phase balanced, the negative sequence meets the national standard requirements, the power factor remains unchanged, no additional power quality management device is required, and the economic benefits are good; (7) the energy storage element stabilizes the DC bus voltage, and the charging and discharging realizes the power cycle; (8) the three-phase AC-DC converter and the three-phase AC-DC converter constitute an AC-DC-AC converter for technical condition testing and verification; (9) the simulation device is connected to the actual line.

[0008] One objective of this invention is to provide a fully continuous three-phase traction power supply system simulation device, comprising n three-phase AC-DC converters simulating n trains, n three-phase transformers, a three-phase universal AC-DC converter AD, a three-phase bus TPB, and a measurement and control unit MC, wherein n≥2; the AC ports of the three-phase AC-DC converters are respectively connected to the three-phase bus TPB through the three-phase transformers, the AC port of the three-phase universal AC-DC converter AD is connected to the three-phase bus TPB, and the measurement and control unit MC controls the operation of the n three-phase AC-DC converters and the three-phase universal AC-DC converter AD.

[0009] Preferably, the simulation device is used to conduct technical condition tests and inspections on the n three-phase AC-DC converters, the three-phase universal AC-DC converter AD, and the AC-DC-AC converter composed of the two.

[0010] As a preferred embodiment, the controller simulates the operating conditions of n trains and the load or tonnage of the trains by controlling the operation of n three-phase AC-DC converters; the controller simulates the active power feedback process by controlling the operation of n three-phase AC-DC converters and the three-phase universal AC-DC converter AD.

[0011] Preferably, the controller MC controls the active power conservation on the AD path of the n three-phase AC-DC converters and the three-phase universal AC-DC converter.

[0012] Preferably, the system also includes current transformers CTA, CTB, and CTC, which are connected in series with phases A, B, and C of the three-phase universal AC-DC converter AD, respectively. The measuring terminals of the controller MC are connected to the measuring terminals of the current transformers CTA, CTB, and CTC, and the control terminals of the controller MC are connected to the control terminals of the n three-phase AC-DC converters and the three-phase universal AC-DC converter AD.

[0013] As a preferred embodiment, the controller MC controls the active power of n three-phase AC-DC converters, and the sum of the active power of the n three-phase AC-DC converters is converged at the AC port of the three-phase universal AC-DC converter AD. The real-time active power at the AC port of the three-phase universal AC-DC converter AD is equal to the sum of the active power of the n three-phase AC-DC converters.

[0014] Preferably, the current measured by the current transformers CTA, CTB, and CTC is used to obtain the real-time active power of the AC port of the three-phase universal AC-DC converter AD. The controller MC controls the operation of the three-phase universal AC-DC converter AD based on the real-time active power of the AC port.

[0015] Preferably, the controller MC outputs n active power signals to control the operation of the n three-phase AC-DC converters, which are used to simulate the operating conditions of n trains in real time. The active power of the controller MC during the operation of the three-phase AC-DC converters is positive, negative, or zero, which indicates that the three-phase AC-DC converters are in rectification, inversion, and shutdown states, respectively, simulating the trains operating in traction, regenerative, inertial, or parking conditions.

[0016] Preferably, the controller MC simulates the train's load or tonnage in real time by controlling the active power of n three-phase AC-DC converters. The greater the active power, the heavier the train load or tonnage, and the smaller the active power, the lighter the train load or tonnage.

[0017] Preferably, n three-phase AC-DC converters and a three-phase universal AC-DC converter AD form an active power feedback path. When the real-time active power of the AC port of the three-phase universal AC-DC converter AD is positive, the controller MC controls the three-phase universal AC-DC converter AD to output active power to the three-phase bus TPB. When the real-time active power of the AC port is negative, the controller MC controls the three-phase universal AC-DC converter AD to absorb active power from the three-phase bus TPB. When the real-time active power of the AC port is 0, the controller MC controls the three-phase universal AC-DC converter AD to shut down.

[0018] Preferably, the n three-phase AC-DC converters are AD1, AD2, ..., ADi, ..., ADn, and the n three-phase transformers are TT1, TT2, ..., TTi, ..., TTn, where i = 1, 2, ..., n, n ≥ 2. The AC port of the three-phase AC-DC converter ADi is connected to the secondary side of the three-phase transformer TTi, and the primary side of the three-phase transformer TTi is connected to the three-phase bus TPB.

[0019] Preferably, the n three-phase transformers have the same turns ratio, and the n three-phase AC-DC converters have the same specifications; the rated capacity S of the three-phase universal AC-DC converter AD is the sum of the rated capacities of the n three-phase AC-DC converters.

[0020] Preferably, the system also includes a DC bus DCB, and the DC side positive and negative terminals of n three-phase AC-DC converters and a three-phase universal AC-DC converter AD are respectively connected to the positive and negative terminals of the DC bus DCB.

[0021] Preferably, it also includes an energy storage device ES, whose port is connected to the DC bus DCB+- pole, and whose control terminal is connected to the control terminal of the measurement and control device MC.

[0022] Preferably, the three-phase bus TPB is connected to the three-phase power supply ABC.

[0023] The simulation device of this invention utilizes the bidirectional controllability of AC-DC converters to simulate trains using three-phase AC-DC converters (ADi), reflecting traction, regenerative, inertial, or parking conditions. It employs n three-phase AC-DC converters to simulate n train loads, with each load isolated by a three-phase isolation transformer to ensure safety. All n three-phase AC-DC converters draw power from the three-phase busbar (TPB) before operation, simulating phase-to-phase connection of the traction network. This facilitates the utilization of regenerative train energy by traction trains, reduces power consumption from the power system, and significantly increases energy-saving effects.

[0024] The system employs n three-phase AC-DC converters to draw power from the three phases of a three-phase AC power grid, simulating a three-phase AC train drawing power from the grid. A three-phase universal AC-DC converter AD is then connected to the three-phase grid, simulating energy feedback and forming a three-phase-three-phase-three-phase self-circulation, internal feedback mode for traction train active power feedback simulation. During this process, the n three-phase AC-DC converters and the universal three-phase AC-DC converter form a loop, ensuring that the instantaneous active power in the path remains constant. No active power flowing through the converters is consumed from the power source; only a small system loss (1 to 2% of rated capacity) is consumed, reducing energy consumption during the test. The three-phase power supply ABC provides the energy required for the internal system operation of the simulation device, making the entire simulation process energy-saving and environmentally friendly.

[0025] The capacity of the three-phase AC-DC converter ADi is determined by the tonnage of the train. After drawing power from n three-phase trains, the power needs to be fed back through the three-phase universal AC-DC converter AD. Therefore, preferably, the rated capacity S of the three-phase universal AC-DC converter AD is the sum of the capacities of n three-phase AC-DC converters to ensure minimum capacity and save costs. This method ensures three-phase balance in the system, meets national standards for negative sequence power, maintains a constant power factor, and eliminates the need for additional power quality control devices, resulting in good economic benefits.

[0026] The simulation device of this invention utilizes a three-phase-three-phase-three-phase self-circulation and internal feedback process to conduct technical condition tests and inspections on an AC-DC-AC converter composed of a three-phase AC-DC converter ADi and a three-phase universal AC-DC converter AD. Specifically, the three-phase AC-DC converter ADi and the three-phase universal AC-DC converter AD constitute an AC-DC-AC converter, and the simulation device is used to conduct technical condition tests and inspections on the aforementioned three-phase AC-DC converter ADi, the three-phase universal AC-DC converter AD, and the AC-DC-AC converter composed of the two.

[0027] The second objective of this invention is to provide a control method for a fully continuous three-phase traction power supply system simulation device. The method is characterized in that the controller MC outputs an active power sequence [S1, S2, ..., Si, ..., Sn] to control the operation of the n three-phase AC-DC converters, wherein the three-phase AC-DC converter ADi is controlled to operate at Si, i = 1, 2, ..., n, n ≥ 2, and -S N i≤Si≤S N i, the rated capacity of the three-phase AC-DC converter ADi is S N i; Si being + indicates that the three-phase AC-DC converter ADi is in rectification mode, representing the traction condition of three-phase train i, where the three-phase AC-DC converter ADi absorbs active power from the three-phase power grid for train traction; Si being - indicates that the three-phase AC-DC converter ADi is in inverter mode, representing the regenerative condition of three-phase train i, where the train undergoes regenerative braking and the three-phase AC-DC converter ADi outputs active power to the three-phase power grid; Si being 0 indicates that the three-phase AC-DC converter ADi is in shutdown mode, representing the inertial or stopping condition of three-phase train i; the total active power of the n three-phase AC-DC converters. The AC ports of the three-phase universal AC-DC converter AD converge;

[0028] Let the rated line voltage of the three-phase power supply ABC be U, the sum of the currents measured by current transformers CTA, CTB, and CTC be I, and the power factor of the train be 1. Then the real-time active power at the AC port of the three-phase universal AC-DC converter AD is:

[0029] When the real-time active power of the AC port of the three-phase universal AC-DC converter AD When the value is 0, the controller MC controls the three-phase universal AC-DC converter AD to stop.

[0030] When the real-time active power of the AC port of the three-phase universal AC-DC converter AD When the value is +, the controller MC controls the three-phase universal AC-DC converter AD to output active power to the three-phase bus TPB, the magnitude of which is UI;

[0031] When the real-time active power of the AC port of the three-phase universal AC-DC converter AD When the value is -, the controller MC controls the three-phase universal AC-DC converter AD to absorb active power from the three-phase bus, the magnitude of which is UI.

[0032] Specifically, the active power sequence [S1, S2, ..., Si, ..., Sn] issued by the controller MC controls n three-phase AC-DC converters, making the power flow of the train load controllable and realizing dynamic simulation of the operation of n trains; the active power Si of train i is controlled within its rated power - S N i to +S N The value of the active power Si of train i is continuously adjusted. The value of Si can simulate the load (i.e., tonnage) of the train in real time. The larger Si is, the heavier the train load, and the smaller Si is, the lighter the train load. At the same time, the sign of the active power Si of train i can simulate the operating conditions of the train in real time. Si is +, Si is -, and Si is 0, which respectively represent the train being in traction, regeneration, inertia, or stopping conditions.

[0033] Among them, the real-time active power of the AC port of the three-phase universal AC-DC converter AD is equal to the sum of the active power of n three-phase AC-DC converters, that is... There are three possible scenarios: (1) For +, active power is absorbed from the three-phase power grid for train traction operation, and the three-phase universal AC-DC converter AD of the internal feedback system outputs active power of size UI to the three-phase bus, thus completing the internal feedback of active power of the traction network; (2) For -, the train regenerative braking outputs active power to the three-phase power grid, and the three-phase universal AC-DC converter AD of the internal feedback system absorbs active power of size UI from the three-phase bus, completing the internal feedback of active power of the traction network; (3) When the value is 0, the three-phase universal AC-DC converter AD shuts down. The above process can simulate the traction load process of multiple trains operating simultaneously under different loads and working conditions, and can ensure the three-phase balance of the system, meet the national standard requirements for negative sequence, and keep the power factor unchanged. No additional power quality management device is required, resulting in good economic benefits. In addition, during this process, n three-phase AC-DC converters form a loop with the three-phase universal AC-DC converter, keeping the instantaneous active power on its path constant. The active power flowing through the converter is not consumed from the power supply, but only a very small system loss (1 to 2% of the rated capacity) is consumed, thereby reducing the energy consumption caused by the test process. The three-phase power supply ABC provides the energy required for the operation of the internal system of the simulation device, and the entire simulation process is energy-saving and environmentally friendly.

[0034] The working principle of this invention is as follows: Utilizing the bidirectional controllability of AC-DC converters, a three-phase AC-DC converter is used to simulate a train. The controller controls the operation of the three-phase AC-DC converter to simulate the train's operation under traction, regenerative, inertial, or parking conditions, as well as the train's load or tonnage. The controller also controls the operation of a three-phase universal AC-DC converter to simulate the power feedback process. This simulates the traction load process of multiple trains operating simultaneously under different loads and conditions, ensuring the conservation of instantaneous active power, reducing energy consumption during the test, guaranteeing three-phase balance of the system, meeting national standards for negative sequence, and maintaining a constant power factor.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] (1) Utilizing the bidirectional controllability of AC-DC converters, three-phase AC-DC converters are used to simulate trains to reflect traction, regeneration, inertia, or parking conditions; n train loads are isolated from each other by three-phase isolation transformers to ensure that each converter operates safely and independently.

[0037] (2) n three-phase AC-DC converters are used to draw current from the three phases of the three-phase AC power grid, and then the three-phase universal AC-DC converter AD is used to connect to the three-phase power grid, thereby forming a three-phase-three-phase-three-phase self-circulation and internal feedback mode to simulate the active power of the traction network train and the energy feedback of the n train loads and the three-phase power grid.

[0038] (3) n three-phase AC-DC converters form a loop with the three-phase AC-DC converters, so that the instantaneous active power on the path remains constant and the active power flowing through the converters is not consumed from the power source. Instead, only a small system loss (1 to 2% of the rated capacity) is consumed to reduce the energy consumption caused by the test process. The three-phase power supply ABC provides the energy required for the operation of the internal system of the simulation device. The whole simulation process is energy-saving and environmentally friendly.

[0039] (4) The active power sequence generated by the MC controller is used to control n three-phase AC-DC converters, so that the power flow of the train load is controllable and the dynamic simulation of the operation process of n trains is realized; the active power of the train is controlled within its rated power - S N i to +S N The system continuously adjusts between i, controlling the magnitude of the active power output to simulate the train's load (tonnage) in real time, and controlling the positive, negative, and zero active power output to simulate the train's traction, regeneration, inertia, or parking conditions in real time, thereby simultaneously simulating the traction load process of multiple trains under different loads and conditions.

[0040] (5) All n three-phase AC-DC converters (i.e. n three-phase train loads) are powered by the three-phase bus TPB and can simulate the traction network to implement phase connection, which is more conducive to the use of regenerated train power by the traction train, reduces the power consumption from the power system, and greatly increases the energy saving effect.

[0041] (6) It can ensure the three-phase balance of the system, meet the national standard requirements for negative sequence, keep the power factor unchanged, and does not require additional power quality management devices, resulting in good economic benefits.

[0042] (7) The energy storage element ES is used to stabilize the DC bus voltage and can also achieve power cycling through charge and discharge control.

[0043] (8) The three-phase-three-phase-three-phase self-circulation and internal feedback process can be used to conduct technical condition tests and inspections on the three-phase AC-DC converter and the three-phase AC-DC converter to form an AC-DC-AC converter.

[0044] (9) The power electronic converter used in the simulation device is easy to implement in hardware, suitable for on-site experimental testing, and also suitable for simulation analysis before the actual line is put into operation. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention.

[0046] Figure 1 This is a schematic diagram of one structure of the present invention. Detailed Implementation

[0047] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] like Figure 1 As shown, this embodiment provides a fully continuous three-phase traction power supply system simulation device, including n three-phase transformers, namely three-phase transformer TT1, three-phase transformer TT2, ..., three-phase transformer TTn; three-phase AC-DC converters simulating n trains, namely three-phase AC-DC converter AD1, three-phase AC-DC converter AD2, ..., three-phase AC-DC converter ADn, where n≥2; a three-phase universal AC-DC converter AD; a DC bus DCB; and a three-phase bus TPB;

[0050] The DC side positive and negative terminals of the three-phase AC-DC converters AD1, AD2, ..., ADn, and the three-phase universal AC-DC converter AD are respectively connected to the positive and negative terminals of the DC bus DCB; the AC port of the three-phase AC-DC converter AD1 is connected to the three-phase bus TPB through the three-phase transformer TT1, the AC port of the three-phase AC-DC converter AD2 is connected to the three-phase bus TPB through the three-phase transformer TT2, ..., the AC port of the three-phase AC-DC converter ADn is connected to the three-phase bus TPB through the three-phase transformer TTn; the AC port of the three-phase universal AC-DC converter AD is connected to the three-phase bus TPB; the three-phase bus TPB is connected to the three-phase power supply ABC.

[0051] The simulation device of the present invention also includes current transformers CTA, CTB, and CTC, which are connected in series with phases A, B, and C of the AC side of the three-phase universal AC-DC converter AD, respectively.

[0052] The simulation device of the present invention also includes a measurement and control unit MC. The measuring terminal of the measurement and control unit MC is connected to the measuring terminals of the current transformers CTA, CTB, and CTC. The control terminal of the measurement and control unit MC is connected to the control terminal of the three-phase AC-DC converter AD1, the three-phase AC-DC converter AD2, ..., the three-phase AC-DC converter ADn and the three-phase universal AC-DC converter AD.

[0053] In this embodiment, the bidirectional controllability of the AC-DC converter is utilized, and a three-phase AC-DC converter ADi is used to simulate a train, reflecting traction, regenerative, inertial, or parking conditions. n three-phase AC-DC converters are used to simulate n train loads, and each train load is isolated from the others by a three-phase isolation transformer to ensure safety. All n three-phase AC-DC converters draw power from the three-phase bus TPB before operation, which can simulate the same-phase connection of the traction network. This is more conducive to the utilization of regenerative train power by traction trains, reduces power consumption from the power system, and greatly increases energy-saving effect.

[0054] In this embodiment, n three-phase AC-DC converters are used to draw power from the three phases of the three-phase AC power grid, which can simulate the three-phase AC train drawing power from the three-phase AC power grid. Then, a three-phase universal AC-DC converter AD is used to connect to the three-phase power grid, which can simulate energy feedback with the three-phase power grid and form a three-phase-three-phase-three-phase self-circulation, internal feedback mode to simulate the active power of the traction network train. In this process, the n three-phase AC-DC converters and the three-phase universal AC-DC converter form a loop, so that the instantaneous active power on the path remains constant. The active power flowing through the converter is not consumed from the power source, but only a very small system loss (1 to 2% of the rated capacity) is consumed to reduce the energy consumption caused by the test process. The three-phase power supply ABC provides the energy required for the operation of the internal system of the simulation device. The entire simulation process is energy-saving and environmentally friendly.

[0055] As a preferred option, the rated capacity of the three-phase transformer TTi is S. T i, the rated capacity of the three-phase AC-DC converter ADi is S N i, i = 1, 2, ..., n, n ≥ 2, different capacities represent different train tonnages. The rated capacity S of the three-phase universal AC-DC converter AD is the sum of the capacities of the n three-phase AC-DC converters, i.e. Preferably, the three-phase transformers TTi have the same turns ratio, and the three-phase AC-DC converters ADi have the same specifications.

[0056] Preferably, the controller MC outputs an active power sequence [S1, S2, ..., Si, ..., Sn] to control the operation of the n three-phase AC-DC converters, wherein the three-phase AC-DC converter ADi is controlled to operate at Si, i = 1, 2, ..., n, n ≥ 2, and -S N i≤Si≤S N i; the total active power of the n three-phase AC-DC converters The current converges on the AC side of the three-phase universal AC-DC converter AD. The controller MC obtains the real-time active power on the AC side of the three-phase universal AC-DC converter AD by measuring the current through the current transformers CTA, CTB, and CTC, and controls the three-phase universal AC-DC converter AD to operate at...

[0057] In this embodiment, the capacity of the three-phase AC-DC converter ADi is determined by the tonnage of the train. After drawing power from n three-phase trains, the power needs to be fed back through the three-phase universal AC-DC converter AD. Therefore, preferably, the rated capacity S of the three-phase universal AC-DC converter AD is the sum of the capacities of the n three-phase AC-DC converters to ensure minimum capacity and save costs. This method ensures three-phase balance in the system, meets national standards for negative sequence power, maintains a constant power factor, and eliminates the need for additional power quality control devices, resulting in good economic benefits.

[0058] Preferably, the simulation device of the present invention further includes an energy storage device ES, whose port is connected to the DC bus DCB+- pole, and whose control terminal is connected to the control terminal of the measurement and control device MC.

[0059] Preferably, the simulation device of the present invention utilizes a three-phase-three-phase-three-phase self-circulation, internal feedback process to conduct technical condition tests and inspections on an AC-DC-AC converter composed of a three-phase AC-DC converter ADi and a three-phase universal AC-DC converter AD. Specifically, the three-phase AC-DC converter ADi and the three-phase universal AC-DC converter AD constitute an AC-DC-AC converter, and the simulation device is used to conduct technical condition tests and inspections on the aforementioned three-phase AC-DC converter ADi, the three-phase universal AC-DC converter AD, and the AC-DC-AC converter composed of the two.

[0060] Example 2

[0061] like Figure 1 As shown, this embodiment provides a control method based on the fully continuous three-phase traction power supply system simulation device provided in Embodiment 1.

[0062] The controller MC outputs an active power sequence [S1, S2, ..., Si, ..., Sn] to control the operation of the n three-phase AC-DC converters. Specifically, it controls three-phase AC-DC converter AD1 to operate at S1, AD2 to operate at S2, ..., and ADn to operate at Sn, thereby ensuring that the active power of train 1 is S1 and -S... N 1≤S1≤S N 1. The active power of train 2 is S2 and -S N 2≤S2≤S N 2, ..., the active power of train n is Sn and -S N n≤Sn≤S N n, the power factor of the train is 1;

[0063] Taking train 1 as an example, if S1 = 3MW, it means that the three-phase AC-DC converter AD1 is in rectification mode, which means that train 1 is working in traction mode; if S1 = -3MW, it means that the three-phase AC-DC converter AD1 is in inverter mode, which means that train 1 is working in regenerative mode; if S1 = 0MW, it means that the three-phase AC-DC converter AD1 is in shutdown mode, which means that train 1 is in inertial or parking mode; and so on up to n trains.

[0064] The sum of active power of the n three-phase AC-DC converters They converge on the AC side of the three-phase universal AC-DC converter AD;

[0065] Let the rated line voltage of the three-phase power supply ABC be U, and the sum of the currents measured by current transformers CTA, CTB, and CTC be I. Then the real-time active power on the AC side of the three-phase universal AC-DC converter AD is:

[0066] When the real-time active power of the AC side of the three-phase universal AC-DC converter AD When the value is 0, the controller MC controls the three-phase universal AC-DC converter AD to stop.

[0067] When the real-time active power of the AC side of the three-phase universal AC-DC converter AD When the value is +, the controller MC controls the three-phase universal AC-DC converter AD to output active power to the three-phase bus TPB, the magnitude of which is UI;

[0068] When the real-time active power of the AC side of the three-phase universal AC-DC converter AD When the value is -, the controller MC controls the three-phase universal AC-DC converter AD to absorb active power from the three-phase bus, the magnitude of which is UI.

[0069] Taking three trains as an example, if S1 = 3MW, S1 = -1MW, and S1 = -2MW, then the controller MC controls the three-phase universal AC-DC converter AD to shut down; if S1 = 3MW, S1 = -1MW, and S1 = 1MW, then the controller MC controls the three-phase universal AC-DC converter AD to output active power to the three-phase bus TPB, with a magnitude of 3MW; if S1 = -3MW, S1 = -1MW, and S1 = 1MW, then the controller MC controls the three-phase universal AC-DC converter AD to absorb active power from the three-phase bus, with a magnitude of 3MW.

[0070] In this embodiment, the active power sequence [S1, S2, ..., Si, ..., Sn] issued by the controller MC controls n three-phase AC-DC converters. Specifically, the controller MC issues active power S1 to control three-phase AC-DC converter AD1 so that the active power of train 1 is S1; the controller MC issues active power S2 to control three-phase AC-DC converter AD2 so that the active power of train 2 is S2, ..., the controller MC issues active power Sn to control three-phase AC-DC converter ADn so that the active power of train n is Sn. This makes the power flow of the train load controllable, realizing dynamic simulation of the operation process of n trains; controlling the active power Si of train i to its rated power - S N i to +S N The value of the active power Si of train i is continuously adjusted. The value of Si can simulate the load (i.e., tonnage) of the train in real time. The larger Si is, the heavier the train load, and the smaller Si is, the lighter the train load. At the same time, the sign of the active power Si of train i can simulate the operating conditions of the train in real time. Si is +, Si is -, and Si is 0, which respectively represent the train being in traction, regeneration, inertia, or stopping conditions.

[0071] In this embodiment, the real-time active power on the AC side of the three-phase universal AC-DC converter AD is equal to the sum of the active power of n three-phase AC-DC converters, that is... There are three possible scenarios: (1) For +, active power is absorbed from the three-phase power grid for train traction operation, and the three-phase universal AC-DC converter AD of the internal feedback system outputs active power of size UI to the three-phase bus, thus completing the internal feedback of active power of the traction network; (2) For -, the train regenerative braking outputs active power to the three-phase power grid, and the three-phase universal AC-DC converter AD of the internal feedback system absorbs active power of size UI from the three-phase bus, completing the internal feedback of active power of the traction network; (3) When the value is 0, the three-phase universal AC-DC converter AD shuts down. The above process can simulate the traction load process of multiple trains operating simultaneously under different loads and working conditions, and can ensure the three-phase balance of the system, meet the national standard requirements for negative sequence, and keep the power factor unchanged. No additional power quality management device is required, resulting in good economic benefits. In addition, during this process, n three-phase AC-DC converters form a loop with the three-phase universal AC-DC converter, keeping the instantaneous active power on its path constant. The active power flowing through the converter is not consumed from the power supply, but only a very small system loss (1 to 2% of the rated capacity) is consumed, thereby reducing the energy consumption caused by the test process. The three-phase power supply ABC provides the energy required for the operation of the internal system of the simulation device, and the entire simulation process is energy-saving and environmentally friendly.

[0072] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, 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 considered within the scope of protection of the present invention.

Claims

1. A full-through three-phase traction power supply system simulation device, characterized by, The system includes n three-phase AC-DC converters, n three-phase transformers, a three-phase universal AC-DC converter AD, a three-phase bus TPB, and a controller MC, simulating n trains, where n ≥ 2. The AC ports of the three-phase AC-DC converters are connected to the three-phase bus TPB through the three-phase transformers, and the AC port of the three-phase universal AC-DC converter AD is connected to the three-phase bus TPB. The controller MC controls the operation of the n three-phase AC-DC converters and the three-phase universal AC-DC converter AD to simulate the active power feedback process. The controller MC outputs n active power signals to control the operation of the n three-phase AC-DC converters, which are used to simulate the operating conditions of n trains in real time. The active power of the three-phase AC-DC converters is positive, negative, or zero when the controller MC controls them to be in rectification, inversion, or shutdown states, respectively, which means that the three-phase AC-DC converters are in traction, regenerative, inertial, or parking states, respectively.

2. The full-penetration three-phase traction power supply system simulation device according to claim 1, characterized in that, The simulation device is used to conduct technical condition tests and inspections on the n three-phase AC-DC converters, the three-phase universal AC-DC converter AD, and the AC-DC-AC converter composed of the two.

3. The simulation device for a fully continuous three-phase traction power supply system according to claim 1, characterized in that, The controller simulates the operating conditions and load of n trains by controlling the operation of n three-phase AC-DC converters.

4. The simulation device for a fully continuous three-phase traction power supply system according to claim 1, characterized in that, The controller MC controls the active power conservation on the AD path of n three-phase AC-DC converters and three-phase universal AC-DC converters.

5. A simulation device for a fully continuous three-phase traction power supply system according to any one of claims 1-4, characterized in that, It also includes current transformers CTA, CTB, and CTC, which are connected in series with phases A, B, and C of the AC port of the three-phase universal AC-DC converter AD, respectively. The measuring terminal of the measuring and controlling device MC is connected to the measuring terminals of the current transformers CTA, CTB, and CTC, and the control terminal of the measuring and controlling device MC is connected to the control terminals of the n three-phase AC-DC converters and the three-phase universal AC-DC converter AD.

6. The simulation device for a fully continuous three-phase traction power supply system according to claim 5, characterized in that, The controller MC controls the active power of n three-phase AC-DC converters. The total active power of the n three-phase AC-DC converters is converged at the AC port of the three-phase universal AC-DC converter AD. The real-time active power at the AC port of the three-phase universal AC-DC converter AD is equal to the total active power of the n three-phase AC-DC converters.

7. A simulation device for a fully continuous three-phase traction power supply system according to claim 6, characterized in that, The current measured by the current transformers CTA, CTB, and CTC is used to obtain the real-time active power of the AC port of the three-phase universal AC-DC converter AD. The controller MC controls the operation of the three-phase universal AC-DC converter AD based on the real-time active power of the AC port.

8. A fully continuous three-phase traction power supply system simulation device according to any one of claims 1-4 and 6-7, characterized in that, The controller MC simulates the train's load or tonnage in real time by controlling the active power of n three-phase AC-DC converters. The greater the active power, the heavier the train load or tonnage, and the smaller the active power, the lighter the train load or tonnage.

9. A simulation device for a fully continuous three-phase traction power supply system according to claim 7, characterized in that, n three-phase AC-DC converters and a three-phase universal AC-DC converter AD form an active power feedback path. When the real-time active power of the AC port of the three-phase universal AC-DC converter AD is positive, the controller MC controls the three-phase universal AC-DC converter AD to output active power to the three-phase bus TPB. When the real-time active power of the AC port is negative, the controller MC controls the three-phase universal AC-DC converter AD to absorb active power from the three-phase bus TPB. When the real-time active power of the AC port is 0, the controller MC controls the three-phase universal AC-DC converter AD to shut down.

10. A fully continuous three-phase traction power supply system simulation device according to any one of claims 1-4, 6-7, and 9, characterized in that, There are n three-phase AC-DC converters, namely AD1, AD2, ..., ADi, ..., ADn, and n three-phase transformers, namely TT1, TT2, ..., TTi, ..., TTn, where i = 1, 2, ..., n, n ≥ 2. The AC port of the three-phase AC-DC converter ADi is connected to the secondary side of the three-phase transformer TTi, and the primary side of the three-phase transformer TTi is connected to the three-phase bus TPB.

11. A fully continuous three-phase traction power supply system simulation device according to any one of claims 1-4, 6-7, and 9, characterized in that, The n three-phase transformers have the same turns ratio, and the n three-phase AC-DC converters have the same specifications; the rated capacity S of the three-phase universal AC-DC converter AD is the sum of the rated capacities of the n three-phase AC-DC converters.

12. A fully continuous three-phase traction power supply system simulation device according to any one of claims 1-4, 6-7, and 9, characterized in that, It also includes the DC bus DCB, and the DC side positive and negative terminals of n three-phase AC-DC converters and three-phase universal AC-DC converter AD are respectively connected to the positive and negative terminals of the DC bus DCB.

13. A simulation device for a fully continuous three-phase traction power supply system according to claim 12, characterized in that, It also includes an energy storage device ES, whose port is connected to the DC bus DCB+- pole, and whose control terminal is connected to the control terminal of the controller MC.

14. A fully continuous three-phase traction power supply system simulation device according to any one of claims 1-4, 6-7, 9, and 13, characterized in that, The three-phase bus TPB is connected to the three-phase power supply ABC.

15. A control method for a simulation device of a fully continuous three-phase traction power supply system as described in any one of claims 5-14, characterized in that, The controller MC outputs an active power sequence [S1, S2, ..., Si, ..., Sn] to control the operation of the n three-phase AC-DC converters, wherein the three-phase AC-DC converter ADi is controlled to operate at Si, i=1,2,...,n, n≥2, and -S N i≤Si≤S N i, the rated capacity of the three-phase AC-DC converter ADi is S N i; A + value for Si indicates that the three-phase AC-DC converter ADi is in rectification mode, representing the traction condition of the three-phase train i; a - value for Si indicates that the three-phase AC-DC converter ADi is in inverter mode, representing the regenerative condition of the three-phase train i; a 0 value for Si indicates that the three-phase AC-DC converter ADi is in shutdown mode, representing the inertial or stopping condition of the three-phase train i; the total active power of the n three-phase AC-DC converters. The AC ports of the three-phase universal AC-DC converter AD converge; Let the rated line voltage of the three-phase power supply ABC be U, the sum of the currents measured by current transformers CTA, CTB, and CTC be I, and the power factor of the train be 1. Then the real-time active power at the AC port of the three-phase universal AC-DC converter AD is UI. ; When the real-time active power UI of the AC port of the three-phase universal AC-DC converter AD When the value is 0, the controller MC controls the three-phase universal AC-DC converter AD to stop. When the real-time active power UI at the AC port of the three-phase universal AC-DC converter AD = When the value is +, the controller MC controls the three-phase universal AC-DC converter AD to output active power to the three-phase bus TPB, the magnitude of which is UI; When the real-time active power UI at the AC port of the three-phase universal AC-DC converter AD = When the value is -, the controller MC controls the three-phase universal AC-DC converter AD to absorb active power from the three-phase bus, the magnitude of which is UI.

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