Converter grid-connected current harmonic suppression method and device for traction power supply system

Abstract

The invention relates to a converter grid-connected current harmonic suppression method and device for a traction power supply system, and is applied to the technical field of rail transit traction power supply. The method comprises the following steps: acquiring traction power supply electrical parameter information and grid-connected output current information of each slave controller in a grid-connected converter; determining a grid-connected reference current according to the traction power supply electrical parameter information; and based on the grid-connected reference current, performing harmonic suppression and phase lead compensation on the grid-connected output current information by utilizing closed-loop control of multiple quasi-proportional resonance based on multiple phase lead compensation, and determining the current grid-connected output current. Through multiple quasi-proportional resonance control, the harmonic content of steady-state current output by the grid-connected converter can be suppressed; and in order to avoid control time delay caused by multiple quasi-proportional resonance control, the phase is subjected to lead compensation, so that the obtained current grid-connected output current meets the response speed requirement, and the electric energy quality of the grid-connected current is improved. Therefore, the operation stability of the traction power supply system can be improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of rail transit traction power supply, and particularly to a method and device for suppressing harmonic currents of a grid-connected converter in a traction power supply system. Background Art

[0002] With the continuous progress and development of power electronics technology, power electronic devices in the power supply system have been widely used. At the same time, the increasing number of nonlinear loads has led to increasingly serious harmonic problems in the power supply system. The existence of a large number of harmonics in the power supply system causes harmonic resonance problems in the power supply system, greatly reducing the quality of electric energy. Therefore, it is necessary to suppress harmonics.

[0003] Generally, based on a specific pulse width modulation control method for harmonic elimination, the switching angles of the pulse width modulation waveform can be calculated to achieve the filtering of harmonic currents. However, such a harmonic suppression method has a complex solution process, may have no solution, and the continuity of the solution is limited, resulting in difficulty in implementing closed-loop control. Therefore, the operation stability of the traction power supply system will be reduced. Summary of the Invention

[0004] The present disclosure provides a method and device for suppressing harmonic currents of a grid-connected converter in a traction power supply system, which can improve the operation stability of the traction power supply system.

[0005] In a first aspect, the present disclosure provides a method for suppressing harmonic currents of a grid-connected converter in a traction power supply system. The traction power supply system includes a power grid, renewable energy, an energy storage system, and a traction network. The power grid, the renewable energy, and the energy storage system are respectively connected to the traction network. The renewable energy and the energy storage system supply power to the traction network through a grid-connected converter. The method includes:

[0006] Obtain the traction power supply electrical parameter information and grid-connected output current information of each slave controller in the grid-connected converter;

[0007] Determine a grid-connected reference current according to the traction power supply electrical parameter information;

[0008] Based on the grid-connected reference current, use a closed-loop control of multiple quasi-proportional resonance with multiple phase lead compensations to perform harmonic suppression and phase lead compensation on the grid-connected output current information, and determine the current grid-connected output current.

[0009] Optionally, the step of using a closed-loop control of multiple quasi-proportional resonance with multiple phase lead compensations based on the grid-connected reference current to perform harmonic suppression and phase lead compensation on the grid-connected output current information and determine the current grid-connected output current includes:

[0010] Determine a current error signal according to the grid-connected output current information and the grid-connected reference current;

[0011] Based on the current error signal, use a plurality of parallel quasi-proportional resonant controllers to perform harmonic suppression and phase lead compensation on the grid-connected output current information, and determine a grid-connected reference voltage. Each of the quasi-proportional resonant controllers is connected in series with a phase lead compensator;

[0012] Based on the grid-connected reference voltage, use voltage feedforward control, carrier phase-shifted PWM converter control, and converter filter function to determine the current grid-connected output current.

[0013] Optionally, the determining the current grid-connected output current based on the grid-connected reference voltage, using voltage feedforward control, carrier phase-shifted PWM converter control, and converter filter function includes:

[0014] Modulate the grid reference voltage after voltage feedforward control according to the converter filter function in the closed-loop control of multiple quasi-proportional resonators based on multiple phase lead compensations to determine a modulation wave;

[0015] Based on the carrier phase-shifted PWM converter control, compare the modulation wave with a phase-shifted triangular carrier to generate a pulse width modulation signal;

[0016] Determine the bridge port voltage of each of the slave controllers according to the pulse width modulation signal;

[0017] Determine the current grid-connected output current according to the bridge port voltage and the filter inductor transfer function in the closed-loop control of multiple quasi-proportional resonators based on multiple phase lead compensations.

[0018] Optionally, before comparing the modulation wave with the phase-shifted triangular carrier to generate a pulse width modulation signal, the method further includes:

[0019] Determine the phase shift period of the phase-shifted triangular carrier according to the number of cascaded H-bridges of each slave controller in the grid-connected converter;

[0020] Determine the equivalent switching frequency of the current grid-connected output current according to the phase shift period.

[0021] Optionally, the obtaining the traction power supply electrical parameter information of each slave controller in the grid-connected converter includes:

[0022] Obtain the traction load power information of the traction power supply system;

[0023] Allocate the traction load power information according to the configuration parameters of each slave controller in the grid-connected converter to determine the traction power supply electrical parameter information of each slave controller.

[0024] Optionally, determining the grid-connected reference current according to the traction power supply electrical parameter information includes:

[0025] Based on the power loops of each of the slave controllers, the active power reference information and the reactive power reference information in the traction power supply electrical parameter information, determine the grid-connected reference current of each sub-controller in each of the slave controllers.

[0026] In a second aspect, the present disclosure provides a harmonic suppression device for a traction power supply system. The traction power supply system includes a power grid, a renewable energy source, an energy storage system, and a traction network. The power grid, the renewable energy source, and the energy storage system are respectively connected to the traction network. The renewable energy source and the energy storage system supply power to the traction network through a grid-connected inverter. The device includes:

[0027] An acquisition module, configured to acquire the traction power supply electrical parameter information and the grid-connected output current information of each slave controller in the grid-connected inverter;

[0028] A first determination module, configured to determine the grid-connected reference current according to the traction power supply electrical parameter information;

[0029] A second determination module, configured to perform harmonic suppression and phase lead compensation on the grid-connected output current information by using a closed-loop control based on multiple quasi-proportional resonance with multiple phase lead compensation based on the grid-connected reference current, and determine the current grid-connected output current.

[0030] In a third aspect, the present disclosure provides a computer device, including a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the steps of the method for suppressing the grid-connected current harmonics of the inverter for the traction power supply system described in the above aspect.

[0031] In a fourth aspect, the present disclosure provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for suppressing the grid-connected current harmonics of the inverter for the traction power supply system described in the above aspect are implemented.

[0032] In a fifth aspect, the present disclosure provides a computer program product, including a computer program / instructions. When the computer program is executed by a processor, the steps of the method for suppressing the grid-connected current harmonics of the inverter for the traction power supply system described in the above aspect are implemented.

[0033] In the present disclosure, traction power supply electrical parameter information and grid-connected output current information of each slave controller in the grid-connected converter are obtained; based on the traction power supply electrical parameter information, a grid-connected reference current is determined; based on the grid-connected reference current, harmonic suppression and phase lead compensation are performed on the grid-connected output current information by using a closed-loop control of multiple quasi-proportional resonance based on multiple phase lead compensation to determine the current grid-connected output current. Through the multiple quasi-proportional resonance control, the harmonic content of the steady-state current output by the grid-connected converter can be suppressed; and in order to avoid the control delay caused by the multiple quasi-proportional resonance control, phase lead compensation is performed on the phase so that the obtained current grid-connected output current meets the response speed requirement, improving the power quality of the grid-connected current. Therefore, the operation stability of the traction power supply system can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In the following, the present disclosure will be described in more detail based on embodiments with reference to the drawings:

[0035] Figure 1 It is a flowchart of a method for suppressing harmonic currents of a converter grid connection in a traction power supply system provided by the present disclosure.

[0036] Figure 2 It is a schematic structural diagram of a "grid-source-storage-vehicle" collaborative traction power supply system provided by the present disclosure.

[0037] Figure 3 It is a closed-loop feedback control block diagram of a method for suppressing harmonic currents of a converter grid connection in a traction power supply system provided by the present disclosure.

[0038] Figure 4 It is another flowchart of a method for suppressing harmonic currents of a converter grid connection in a traction power supply system provided by the present disclosure.

[0039] Figure 5 It is a schematic structural diagram of a device for suppressing harmonic currents of a converter grid connection in a traction power supply system provided by the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the application scenario of the present application solution will be described first below.

[0041] With the continuous progress and development of power electronics technology, power electronic devices in the rail transit traction power supply system have been widely used. At the same time, the increasing number of nonlinear loads has led to an increasingly serious harmonic problem in the power supply system. At present, the power supply of electrified railways in China mainly adopts grid power supply. The grid voltage is converted into AC27.5kV through a traction transformer to supply power to the traction load. The power source of this power supply structure is single. After converting the electrical energy of the photovoltaic and energy storage systems through a high-power single-phase inverter and then connecting them to the electrified railway traction power supply system through a step-up transformer, constructing a "grid-source-storage-vehicle" collaborative traction power supply system is the future direction, which has the advantages of economy, greenness and low carbon. However, due to the relatively low switching frequency of the high-power single-phase inverter itself, it will cause more low-order harmonic currents. At the same time, the "grid-source-storage-vehicle" collaborative traction power supply system connects the photovoltaic / energy storage through DC grid connection, and the voltage pulsation of DC grid connection will also affect the low-order harmonics. The existence of a large number of harmonics in the power supply system causes harmonic problems in the power supply system, greatly reducing the quality of electrical energy. Therefore, it is necessary to suppress harmonics.

[0042] At present, based on a specific pulse width modulation control method for harmonic elimination, the switching angles of the pulse width modulation waveform can be calculated to achieve the filtering of harmonic currents. However, such a harmonic suppression method has a complex solution process, may have no solution, and the continuity of the solution is limited, resulting in difficulty in implementing closed-loop control. Therefore, it will reduce the operating stability of the power supply system.

[0043] To solve the above-mentioned technical problems, the present disclosure provides a method and device for suppressing harmonic currents of the grid-connected current of an inverter for a traction power supply system. In the present disclosure, the traction power supply electrical parameter information and the grid-connected output current information of each slave controller in the grid-connected inverter are obtained; based on the traction power supply electrical parameter information, the grid-connected reference current is determined; based on the grid-connected reference current, using a closed-loop control of multiple quasi-proportional resonance based on multiple phase lead compensation, the harmonic suppression and phase lead compensation of the grid-connected output current information are performed to determine the current grid-connected output current. Through multiple quasi-proportional resonance control, the harmonic content of the steady-state current output by the grid-connected inverter can be suppressed; and in order to avoid the control delay caused by multiple quasi-proportional resonance control, the phase is compensated in advance so that the obtained current grid-connected output current meets the response speed requirements, improving the power quality of the grid-connected current. Therefore, the operating stability of the traction power supply system can be improved.

[0044] To enable those skilled in the art to better understand the technical solutions of the present disclosure, and to fully understand and implement how the present disclosure applies technical means to solve technical problems and achieve the corresponding technical effects, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The embodiments of the present disclosure and each feature in the embodiments can be combined with each other on the premise of not conflicting, and the formed technical solutions are all within the protection scope of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

[0045] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present disclosure described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0046] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0047] Example 1

[0048] Figure 1 It is a flowchart of a harmonic suppression method for a traction power supply system provided by the present disclosure. As Figure 1 shown, the method includes:

[0049] S101: Obtain the traction power supply electrical parameter information and grid-connected output current information of each slave controller in the grid-connected converter.

[0050] Specifically, Figure 2 It is a schematic structural diagram of the "grid-source-storage-vehicle" collaborative traction power supply system provided by the present disclosure. As Figure 2As shown in the figure. The system includes a power grid, renewable energy, an energy storage system, a locomotive, and a traction network. The power grid, the renewable energy, and the energy storage system are respectively connected to the traction network. Through a transformer in the traction substation, the power grid voltage is converted into alternating current of 27.5 kV to supply power to the traction load. At the same time, the electricity generated by the photovoltaic, renewable energy, and energy storage system is subjected to power conversion through an inverter and then connected to the traction power supply system of the electrified railway through a step-up transformer to supply power to the traction network.

[0051] The system provides a DC access point for the renewable energy and energy storage system through 1500V DC grid connection. The grid-connected inverter adopts a 5MW-class bidirectional inverter, which can realize the interconnection and intercommunication of energy among multiple links of the collaborative system. The inverter is composed of 4 groups of H-bridge sub-module inverters connected in parallel, and the power of each sub-module is 1.25MW. The electric energy output by the inverter is connected to the 27.5kV feeder of the traction power supply system through a four-split step-up transformer (4×750V / 27.5kV) for power supply. This traction power supply system architecture can make maintenance more convenient, with interconnected structures, and can improve robustness.

[0052] The grid-connected inverter includes a main controller and multiple slave controllers. After the main controller of the grid-connected inverter obtains the current traction load power information, it allocates the power information that each slave controller needs to bear. In this embodiment, when suppressing harmonics in the grid-connected inverter, a closed-loop feedback control method can be adopted. By taking the difference between the grid-connected reference current, the error grid-connected current is obtained, and through a multiple quasi-proportional resonance control strategy based on multiple leading phase compensation, the grid-connected current that reaches the target expectation is output.

[0053] S102: Determine the grid-connected reference current according to the traction power supply electrical parameter information.

[0054] Specifically, the grid-connected reference current is obtained through the power control loop of the slave controller of the grid-connected inverter. That is to say, before the harmonic current is generated, the grid-connected current of the target expected output is determined. Through the traction power supply electrical parameter information corresponding to the slave controller, that is, the active power reference information and the reactive power reference information, the grid-connected reference current corresponding to each slave controller can be calculated and determined.

[0055] S103: Based on the grid-connected reference current, use the closed-loop control of multiple quasi-proportional resonance based on multiple phase leading compensation to suppress harmonics and perform phase leading compensation on the grid-connected output current information, and determine the current grid-connected output current.

[0056] Specifically, in this embodiment, the multi-phase-advance-compensation-based multi-quasi-proportional-resonant control strategy is a closed-loop feedback control strategy. Through the multi-quasi-proportional-resonant controller, the grid-connected current feedback quantity is introduced into the current control link, and the harmonic current in the power supply system can be filtered out. However, the introduction of the multi-quasi-proportional-resonant controller will cause time delay during data transmission and communication, resulting in phase lag. Therefore, it is necessary to perform advance compensation on the phase to improve the power quality and response speed of the grid-connected current.

[0057] In the present disclosure, the traction power supply electrical parameter information and the grid-connected output current information of each slave controller in the grid-connected converter are obtained; according to the traction power supply electrical parameter information, the grid-connected reference current is determined; based on the grid-connected reference current, using the closed-loop control of multi-phase-advance-compensation-based multi-quasi-proportional-resonant, the harmonic suppression and phase advance compensation are performed on the grid-connected output current information to determine the current grid-connected output current. Through the multi-quasi-proportional-resonant control, the harmonic content of the steady-state current output by the grid-connected converter can be suppressed; and in order to avoid the control time delay caused by the multi-quasi-proportional-resonant control, the phase is advanced-compensated so that the obtained current grid-connected output current meets the response speed requirement, improving the power quality of the grid-connected current. Therefore, the operation stability of the traction power supply system can be improved.

[0058] Example 2

[0059] Based on the above embodiment, an exemplary method for performing harmonic suppression and phase advance compensation on the grid-connected output current information by using the closed-loop control of multi-phase-advance-compensation-based multi-quasi-proportional-resonant based on the grid-connected reference current to determine the current grid-connected output current includes:

[0060] According to the grid-connected output current information and the grid-connected reference current, the current error signal is determined; based on the current error signal, the grid-connected output current information is subjected to harmonic suppression and phase advance compensation by using a plurality of parallel quasi-proportional-resonant controllers to determine the grid-connected reference voltage; based on the grid-connected reference voltage, the current grid-connected output current is determined by using voltage feedforward control, carrier phase-shifted PWM converter control, and converter filter function.

[0061] Specifically, Figure 3 is a closed-loop feedback control block diagram of a converter grid-connected current harmonic suppression method provided by the present disclosure, as Figure 3 shown. Figure 3 shows the control flow of the current loop in the slave controller of the slave controller. According to the historical grid-connected output current I gnx and the grid-connected reference current I refnx , the difference is calculated to determine the current error signal i enx .

[0062] Based on the current error signal, the multiple quasi-proportional-resonant control transfer function G M (s) of multiple parallel quasi-proportional-resonant controllers can suppress the harmonics generated by the grid-connected current at this time. However, due to the control delay caused by the multiple quasi-proportional-resonant control and the phase lag caused by the parallel connection of multiple quasi-proportional-resonant controllers, the system may become unstable. Therefore, in this embodiment, each quasi-proportional-resonant controller is connected in series with a phase-advance compensator to perform phase-advance compensation on the grid-connected current while suppressing harmonics, improve the steady-state current tracking ability of the converter, and determine the grid-connected reference voltage U refnx .

[0063] The multiple quasi-proportional-resonant control result can be calculated and determined according to the following formula:

[0064]

[0065] where, K p is the proportional gain, K rh is the resonant gain coefficient, ω h is the resonant frequency of each order, n is the number of slave controllers; ω c is the cut-off frequency, and s is the number of resonances.

[0066] Furthermore, according to the filter function of the converter in the closed-loop control of multiple quasi-proportional-resonant with multiple phase-advance compensations, the grid reference voltage after voltage feed-forward control is modulated to determine the modulation wave; based on the carrier phase-shifted PWM converter control, the modulation wave and the phase-shifted triangular carrier are compared to generate a pulse-width modulation signal; according to the pulse-width modulation signal, the bridge port voltage of each slave controller is determined; according to the bridge port voltage and the filter inductance transfer function in the closed-loop control of multiple quasi-proportional-resonant with multiple phase-advance compensations, the current grid-connected output current is determined.

[0067] Specifically, according to the characteristic equation of the closed-loop transfer function, the multiple quasi-proportional-resonant control parameters can be calculated and determined. According to the resonant frequency and the delay time, the phase-advance compensation value can be determined. Based on the carrier phase-shifted PWM converter G PWM (s) control, the modulation wave V refn and the phase-shifted triangular carrier are compared to generate a pulse-width modulation signal PWM. According to the pulse-width modulation signal, the inverter bridge port voltage U invnx of the grid-connected converter can be determined. According to the bridge port voltage and the filter inductance transfer function in the feedback control strategy, the current grid-connected output current I gnx is determined.

[0068] The phase compensation value can be calculated and determined according to the following formula:

[0069]

[0070] where, Gcl (s) is the closed-loop transfer function, G M (s) is the multiple quasi-proportional-resonant control function, G l (s) is the phase-lead compensation function, G PWM (s) is the converter filter function, G L (s) is the filter inductor transfer function.

[0071] Example 3

[0072] Based on the above embodiments, before generating the pulse width modulation signal by comparing the modulation wave and the phase-shifted triangular carrier wave, the method further includes:

[0073] Determine the phase-shifted period of the phase-shifted triangular carrier wave according to the number of cascaded H-bridges in each slave controller of the grid-connected converter; determine the equivalent switching frequency of the current grid-connected output current according to the phase-shifted period.

[0074] Specifically, the switching frequency of a high-power grid-connected converter is low, which will cause control delay, mainly including calculation delay and pulse width modulation delay. At the same time, there are inevitable time delays in data transmission and communication between different levels of controllers in the coordinated traction power supply system's multi-layer control structure. Therefore, it is necessary to increase the switching frequency of the grid-connected converter. The method of single-pole frequency doubling and carrier phase-shift modulation can be used to stagger the phase-shifted triangular carrier waves of the H-bridges of each slave controller in turn. In this embodiment, the number of cascaded H-bridges is 4 groups. Therefore, within a 180° period, the phase-shifted triangular carrier waves are staggered by 45° in turn, and the final equivalent switching frequency can be determined as f eq = 8f s , where f s is the switching frequency.

[0075] Example 4

[0076] Based on the above embodiments, an exemplary method for obtaining the traction power supply electrical parameter information of each slave controller in the grid-connected converter includes:

[0077] Obtain the traction load power information of the traction power supply system; allocate the traction power information according to the configuration parameters of each slave controller in the grid-connected converter to determine the traction power supply electrical parameter information of each slave controller.

[0078] Specifically, the master controller of the grid-connected converter collects the traction load power information from the traction substation in real time, and through the power distribution algorithm, on the basis of the self-configuration of each slave controller, determines the active power reference information and reactive power reference information borne by each slave controller in the grid-connected converter, and then issues them to the corresponding slave controllers to determine the traction power supply electrical parameter information of each slave controller.

[0079] Example 5

[0080] Based on the above embodiments, an exemplary method for determining the grid-connected reference current according to the traction power supply electrical parameter information includes:

[0081] Based on the power loops of each slave controller, the active power reference information and the reactive power reference information in the traction power supply electrical parameter information, determine the grid-connected reference current of each sub-controller in each slave controller.

[0082] Specifically, through the active power reference information and the reactive power reference information sent by the master controller, the active power reference information and the reactive power reference information of each slave controller can be determined. Based on the power loops of each slave controller, the active power reference information and the reactive power reference information of each slave controller, determine the corresponding active current and reactive current. Based on the grid-connected angular frequency obtained from the phase-locked loop PLL of the master controller, finally determine the grid-connected reference current of each sub-controller.

[0083] The grid-connected reference current of each sub-controller can be calculated and determined according to the following formula:

[0084]

[0085] Where, I refn is the grid-connected reference current of the nth sub-controller, P is the active power reference information, Q is the reactive power reference information, and ω is the angular frequency.

[0086] Example 6

[0087] Based on the above embodiments, this embodiment provides an application example.

[0088] Figure 4 Another flowchart of a harmonic suppression method for a traction power supply system provided by the present disclosure. As Figure 4 shown, the method includes:

[0089] S401: Obtain the grid-connected reference current and the grid-connected output current of each slave controller in the grid-connected converter.

[0090] Specifically, after the master controller collects the load power and calculates the active power reference information and the reactive power reference information, it distributes the power to each slave controller, and the grid-connected reference current of each sub-controller obtained through the power loop calculation. In this embodiment, the closed-loop feedback control compensation method is adopted, so it is necessary to obtain the historical grid-connected output current.

[0091] S402: Calculate the current error signal.

[0092] Calculate the difference between the grid-connected reference current and the grid-connected output current, i.e., the current error signal.

[0093] S403: Determine the grid-connected reference voltage based on the MQPR transfer function with multiple-phase lead compensation and the current error signal.

[0094] S404: Determine the inverter bridge port voltage based on the grid voltage feed-forward control and the converter sensing function.

[0095] Specifically, the grid voltage collected by the main controller can eliminate the influence of some harmonics after being filtered by the low-pass filter. The inverter bridge port voltage can be determined through the converter sensing function.

[0096] S405: Output the final grid-connected current according to the inverter bridge port voltage and the filter inductor transfer function.

[0097] Example 7

[0098] Figure 5 This is a schematic structural diagram of a converter grid-connected current harmonic suppression device provided for the traction power supply system of the present disclosure. As Figure 5 shown, the device 500 includes: an acquisition module 510, a first determination module 520, and a second determination module 530.

[0099] The acquisition module 510 is configured to acquire the traction power supply electrical parameter information and the grid-connected output current information of each slave controller in the grid-connected converter;

[0100] The first determination module 520 is configured to determine the grid-connected reference current according to the traction power supply electrical parameter information;

[0101] The second determination module 530 is configured to perform harmonic suppression and phase lead compensation on the grid-connected output current information based on the grid-connected reference current by using the closed-loop control of multiple quasi-proportional resonance with multiple-phase lead compensation, and determine the current grid-connected output current.

[0102] Optionally, the second determination module is configured to:

[0103] Determine the current error signal according to the grid-connected output current information and the grid-connected reference current;

[0104] Based on the current error signal, perform harmonic suppression and phase lead compensation on the grid-connected output current information by using multiple parallel quasi-proportional resonance controllers, and determine the grid-connected reference voltage, and each of the quasi-proportional resonance controllers is connected in series with a phase lead compensator;

[0105] Based on the grid-connected reference voltage, the current grid-connected output current is determined by using voltage feed-forward control, carrier phase-shifted PWM converter control, and the converter filter function.

[0106] Optionally, the second determination module is configured to:

[0107] Modulate the grid reference voltage after the voltage feed-forward control according to the converter filter function in the closed-loop control of the multi-phase advanced compensation-based multi-quasi-proportional resonance to determine a modulation wave;

[0108] Based on the carrier phase-shifted PWM converter control, compare the modulation wave with the phase-shifted triangular carrier to generate a pulse width modulation signal;

[0109] Determine the bridge port voltages of each of the slave controllers according to the pulse width modulation signal;

[0110] Determine the current grid-connected output current according to the bridge port voltages and the filter inductor transfer function in the closed-loop control of the multi-phase advanced compensation-based multi-quasi-proportional resonance.

[0111] Optionally, the device further includes:

[0112] Before comparing the modulation wave with the phase-shifted triangular carrier to generate a pulse width modulation signal, determine the phase-shifted period of the phase-shifted triangular carrier according to the number of cascaded H-bridges in each slave controller of the grid-connected converter;

[0113] Determine the equivalent switching frequency of the current grid-connected output current according to the phase-shifted period.

[0114] Optionally, the acquisition module is configured to:

[0115] Acquire the traction load power information of the traction power supply system;

[0116] Allocate the traction load power information according to the configuration parameters of each slave controller in the grid-connected converter to determine the traction power supply electrical parameter information of each slave controller.

[0117] Optionally, the first determination module is configured to:

[0118] Based on the power loops of each slave controller, the active power reference information and the reactive power reference information in the traction power supply electrical parameter information, determine the grid-connected reference currents of each sub-controller in each slave controller.

[0119] Based on the above embodiments, the present embodiment provides a computer device, including a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement the steps of the converter grid-connected current harmonic suppression method for the traction power supply system described in the above embodiments.

[0120] In some embodiments of the present embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the converter grid-connected current harmonic suppression method for the traction power supply system described in the above embodiments are implemented.

[0121] In some embodiments of the present embodiment, a computer program product is provided, including a computer program / instructions, and when the computer program is executed by a processor, the steps of the converter grid-connected current harmonic suppression method for the traction power supply system described in the above embodiments are implemented.

[0122] The processor may include, but is not limited to, for example, one or more processors or microprocessors, etc. Each processor may be implemented by an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute the method in the above embodiments.

[0123] The computer-readable storage medium may be implemented by any type of volatile or non-volatile storage device or a combination thereof. The computer-readable storage medium may include, but is not limited to, for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, an EPROM memory, an EEPROM memory, a register, a computer storage medium (such as a hard disk, a floppy disk, a solid state drive, a removable disk, a CD-ROM, a DVD-ROM, a Blu-ray disc, etc.).

[0124] The computer-readable storage medium may also store at least one computer-executable program / instructions, such as computer-readable instructions. The computer-readable storage medium includes, but is not limited to, for example, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory, etc. The computer-readable storage medium may include, for example, read-only memory (ROM), hard disk, flash memory, etc. For example, the non-transitory computer-readable storage medium may be connected to a computing device such as a computer. Then, when the computing device runs the computer-readable instructions stored on the computer-readable storage medium, the various methods described above may be performed.

[0125] In addition, the computer device may further include (but is not limited to) a data bus, an input / output (I / O) bus, a display, and input / output devices (such as a keyboard, a mouse, a speaker, etc.).

[0126] The processor may communicate with external devices via the I / O bus through a wired or wireless network.

[0127] In one embodiment, the at least one computer-executable instruction may also be compiled into or form a software product / computer program product, and when one or more computer-executable instructions are run by a processor, the various functions and / or method steps in the embodiments described in the present technology are performed.

[0128] In the embodiments provided in the present disclosure, it should be understood that the disclosed apparatus and method may also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the drawings show the possible architectures, functions, and operations of the apparatus, method, and computer program product according to multiple embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system for performing the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0129] It should be noted that in this disclosure, the terms "including", "comprising", or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device that includes a series of elements includes not only those elements but also other elements not expressly listed, or elements that are inherent to such process, method, article, or device. Without further limitation, an element limited by the statement "including one..." does not preclude the existence of additional identical elements in the process, method, article, or device that includes the element.

[0130] Although the embodiments disclosed in this disclosure are as described above, the above content is only an embodiment adopted for the convenience of understanding this disclosure and is not intended to limit this disclosure. Any person skilled in the art within the technical field to which this disclosure pertains may make any modifications and changes in the form of implementation and details without departing from the spirit and scope disclosed in this disclosure. However, the scope of patent protection of this disclosure shall still be subject to the scope defined by the appended claims.

Claims

1. A method for suppressing harmonics of grid-connected current of a converter for a traction power supply system, characterized in that: The traction power supply system comprises a power grid, a renewable energy source, an energy storage system and a traction network, wherein the power grid, the renewable energy source and the energy storage system are respectively connected to the traction network, and the renewable energy source and the energy storage system supply power to the traction network through a grid-connected converter, and the method comprises: Acquiring traction power supply electrical parameter information and grid-connected output current information of each slave controller in the grid-connected converter; Determining a grid-connected reference current according to the traction power supply electrical parameter information; Based on the grid-connected reference current, the grid-connected output current information is subjected to harmonic suppression and phase lead compensation by utilizing closed-loop control of multiple quasi-proportional resonances based on multiple phase lead compensation to determine the current grid-connected output current.

2. The method according to claim 1, characterized in that The method of performing harmonic suppression and phase advance compensation on the grid-connected output current information based on the grid-connected reference current and utilizing closed-loop control of multiple quasi-proportional resonances based on multiple phase advance compensation to determine the current grid-connected output current includes: Determining a current error signal according to the grid-connected output current information and the grid-connected reference current; Based on the current error signal, a plurality of parallel quasi-proportional resonant controllers are used to perform harmonic suppression and phase lead compensation on the grid-connected output current information to determine a grid-connected reference voltage, each of the quasi-proportional resonant controllers being connected in series with a phase lead compensator; Based on the grid-connected reference voltage, the current grid-connected output current is determined by utilizing voltage feed-forward control, carrier phase-shifted PWM converter control and converter filter function.

3. The method according to claim 2, characterized in that The method of determining the current grid-connected output current based on the grid-connected reference voltage by utilizing voltage feedforward controllable, carrier phase-shifted PWM converter control and converter filter function comprises: According to the converter filter function in the closed-loop control of multiple quasi-proportional resonance based on multiple phase advance compensation, modulating the grid reference voltage after the voltage feedforward control to determine a modulation wave; Based on the carrier phase-shifted PWM converter control, the modulation wave and the phase-shifted triangular carrier are compared to generate a pulse width modulation signal; Determining the bridge port voltage of each slave controller according to the pulse width modulation signal; The current grid-connected output current is determined according to the bridge port voltage and the filter inductance transfer function in the closed-loop control of multiple quasi-proportional resonance based on multiple phase advance compensation.

4. The method according to claim 3, characterized in that Before comparing the modulated wave with the phase-shifted triangular carrier to generate a pulse width modulation signal, the method further includes: Determining the phase shift period of the phase-shifted triangular carrier according to the number of cascaded H bridges in each slave controller of the grid-connected converter; According to the phase shift period, an equivalent switching frequency of the current grid-connected output current is determined.

5. The method according to claim 1, characterized in that The obtaining of traction power supply electrical parameter information of each slave controller in the grid-connected converter includes: Acquiring traction load power information of the traction power supply system; The traction load power information is distributed according to the configuration parameters of each slave controller in the grid-connected converter, and the traction power supply electrical parameter information of each slave controller is determined.

6. The method according to claim 5, characterized in that The step of determining a grid-connected reference current according to the traction power supply electrical parameter information comprises: Based on the power ring of each slave controller, the active power reference information and the reactive power reference information in the traction power supply electrical parameter information, the grid-connected reference current of each sub-controller in each slave controller is determined.

7. A device for suppressing harmonics of a current connected to a grid in a converter for a traction power supply system, characterized in that: The traction power supply system comprises a power grid, a renewable energy source, an energy storage system and a traction network, wherein the power grid, the renewable energy source and the energy storage system are respectively connected to the traction network, and the renewable energy source and the energy storage system supply power to the traction network through a grid-connected converter. The device comprises: An acquisition module, used to acquire traction power supply electrical parameter information and grid-connected output current information of each slave controller in the grid-connected converter; A first determination module, used to determine a grid-connected reference current according to the traction power supply electrical parameter information; The second determination module is used to perform harmonic suppression and phase lead compensation on the grid-connected output current information based on the grid-connected reference current and utilize closed-loop control of multiple quasi-proportional resonances based on multiple phase lead compensation to determine the current grid-connected output current.

8. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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