Distributed new energy access traction power supply cascade system and control method and device

Abstract

The invention provides a cascade system for accessing distributed new energy to traction power supply and a control method and device. The cascade system comprises at least one cascade unit; the cascade unit comprises a photovoltaic module, an active bridge type DC / DC converter, an H-bridge converter, an energy storage DC / DC converter and an energy storage unit; wherein the positive and negative output ports of the photovoltaic module are respectively connected with the positive and negative ports of the input end of the active bridge type DC / DC converter; the output port of the active bridge DC / DC converter is connected with the input port of the H-bridge converter; positive and negative output ports of the energy storage unit are respectively connected with positive and negative ports of the input end of the energy storage DC / DC converter; and the output port of the energy storage DC / DC converter is connected with the input port of the H-bridge converter. According to the invention, photovoltaic and energy storage can be merged into the railway traction system contact network through a cascade connection mode, a grid connection mode of a traditional power frequency transformer is replaced, the energy conversion efficiency is improved, and the electric energy quality is improved.

Description

Technical Field

[0001] The present application relates to the field of electrified railway traction power supply systems, and specifically to a cascade system for accessing distributed new energy to railway traction power supply and a control method and device thereof. Background Art

[0002] Electrified railways are a large-scale user of the power system, and their energy consumption is huge. The land resources along the railway are abundant, the roof area of ​​railway stations is huge, and there are many new energy application scenarios, but the proportion of new energy development is very low.

[0003] Therefore, the integration and development of new energy power generation and existing railway infrastructure is an inevitable trend to achieve energy transformation in the railway field. In the current total power consumption of railways, traction power consumption accounts for the main part of the total power consumption of railways, and the rest is non-traction power consumption such as railway 10kV through-lines and station buildings. In the existing schemes for direct access of new energy to the railway 25kV traction power supply system, there are two technical routes: one is centralized, which means that large-scale and large-capacity new energy is accessed in a centralized manner in the railway traction substation. Photovoltaic and energy storage collect energy through the DC bus, and then are uniformly inverted and then boosted by transformers and incorporated into the railway traction network; the other is distributed, which means small and medium-capacity distributed access. Photovoltaic and energy storage are directly inverted into low-voltage AC through multiple single-phase inverters. After the AC is collected, it is uniformly boosted by transformers and incorporated into the railway traction network. However, in both of the above technical routes, the new energy power generation system is collected and then connected to the railway 25kV traction network through transformer boosting, and then consumed by the train.

[0004] Traditional power frequency transformers not only occupy a large area, have high operating noise, require special insulation treatment, but also require special treatment of the installation environment. With the continuous development of power electronics technologies such as high-frequency technology and multi-module cascade technology, new power electronic transformers can replace traditional power frequency transformers, thereby reducing the size and weight of equipment, saving installation space, being clean and environmentally friendly, improving energy conversion efficiency, and improving power quality.

[0005] Due to the narrow and long power supply network characteristics of the railway itself, and considering the decentralized distribution of photovoltaic resources along the railway to the railway traction power supply system, it is necessary to develop a cascade system for accessing new energy to the railway traction power supply and the corresponding control method.

[0006] This section is intended to provide a background or context to the embodiments of the invention recited in the claims. No admission is made that the description herein is prior art by inclusion in this section. Summary of the invention

[0007] In response to the problems in the prior art, the present application provides a cascade system for accessing new energy to railway traction power supply and a control method and device thereof, which can realize the integration of photovoltaics and energy storage into the railway traction system contact network through a cascade manner, replacing the traditional grid-connected form of industrial frequency transformers, thereby improving energy conversion efficiency and enhancing power quality.

[0008] In order to solve the above technical problems, this application provides the following technical solutions:

[0009] In a first aspect, the present application provides a new energy access railway traction power supply cascade system, comprising: at least one cascade unit; the cascade unit comprises a photovoltaic component, an active bridge DC / DC converter, an H-bridge converter, an energy storage DC / DC converter and an energy storage unit;

[0010] Among them, the output positive and negative ports of the photovoltaic module are respectively connected to the positive and negative ports of the input end of the active bridge DC / DC converter; the output port of the active bridge DC / DC converter is connected to the input port of the H-bridge converter; the output positive and negative ports of the energy storage unit are respectively connected to the positive and negative ports of the input end of the energy storage DC / DC converter; the output port of the energy storage DC / DC converter is connected to the input port of the H-bridge converter.

[0011] Furthermore, the active bridge DC / DC converter is a single active bridge DC / DC converter or a dual active bridge DC / DC converter.

[0012] Further, the single active bridge DC / DC converter comprises: a first bridge arm formed by a first IGBT and a second IGBT connected in series; a second bridge arm formed by a third IGBT and a fourth IGBT connected in series; a third bridge arm formed by a first diode and a second diode connected in series; and a fourth bridge arm formed by a third diode and a fourth diode connected in series.

[0013] Among them, the first bridge arm and the second bridge arm are both connected in parallel with the input DC capacitor; the midpoint of the second bridge arm is connected to one end point of the inductor; the other end point of the inductor and the midpoint of the first bridge arm are respectively connected to one end point of the primary winding of the intermediate frequency transformer; the midpoint of the first bridge arm is connected to the other end point of the primary side of the intermediate frequency transformer; the third bridge arm and the fourth bridge arm are connected in parallel with the intermediate DC capacitor; the midpoint of the third bridge arm is connected to one end point of the secondary winding of the intermediate frequency transformer; the midpoint of the fourth bridge arm is connected to the other end point of the secondary winding of the intermediate frequency transformer.

[0014] Furthermore, the H-bridge converter comprises: a fifth bridge arm formed by a fifth IGBT and a sixth IGBT connected in series; and a sixth bridge arm formed by a seventh IGBT and an eighth IGBT connected in series.

[0015] Furthermore, when there are N cascade units, the midpoint of the sixth bridge arm of the first cascade unit is connected to the traction power supply contact network; the midpoint of the fifth bridge arm of the n-1th cascade unit is connected to the midpoint of the sixth bridge arm of the nth cascade unit; the midpoint of the fifth bridge arm of the Nth cascade unit is connected to the rail; wherein, <n<N。

[0016] In a second aspect, the present application provides a control method for a new energy access railway traction power supply cascade system, which is applied to the new energy access railway traction power supply cascade system, including:

[0017] Performing DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit;

[0018] According to the control power of each cascade unit, the voltage and current of the traction power supply contact network, the grid-connected current of the H-bridge converter of each cascade unit is controlled to obtain the driving signal of the H-bridge converter of each cascade unit.

[0019] Furthermore, the output current and output voltage of the active bridge DC / DC converter of each cascade unit are controlled by direct current voltage to obtain the control power of each unit, including:

[0020] The actual output current value and the actual output voltage value of the intermediate DC link of each cascade unit are independently tracked and controlled by an active bridge DC / DC converter to obtain the output voltage reference value of the maximum power point of each cascade unit;

[0021] Inputting the actual value of the output voltage into a notch filter to obtain the actual value of the output voltage after notching;

[0022] After inputting the difference between the actual value of the output voltage after the notch and the reference value of the output voltage into the PI controller, the output signal of the PI controller is multiplied by the actual value of the output voltage after the notch to obtain the control power of each cascade unit;

[0023] The control power of each cascade unit is accumulated to obtain the total control power.

[0024] Furthermore, the grid-connected current control of the H-bridge converter of each cascade unit is performed according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and the driving signal of the H-bridge converter of each cascade unit is obtained, including:

[0025] Determining the voltage amplitude and voltage phase of the traction power supply contact network by using a phase-locked loop;

[0026] Inputting the current of the traction power supply overhead line into a second-order generalized integrator to obtain two currents with the same frequency and amplitude and a phase difference of 90°;

[0027] Performing Park transformation on the two currents with the same frequency and amplitude and a phase difference of 90° and the voltage phase to obtain the d-axis actual value and the q-axis actual value corresponding to the current of the traction power supply overhead line;

[0028] Determining a d-axis reference value corresponding to the current of the traction power supply contact network according to the total control power and the voltage amplitude, and setting a q-axis reference value corresponding to the current of the traction power supply contact network to zero;

[0029] Inputting the d-axis actual value, the q-axis actual value, the d-axis reference value and the q-axis reference value into a PI regulator to obtain an active modulation voltage and a reactive modulation voltage;

[0030] Obtaining a phase difference between the voltage phase and the modulation voltage phase and a total modulation voltage amplitude according to the active modulation voltage and the reactive modulation voltage;

[0031] The total control power, the control power of each cascade unit, the actual value of the output voltage after notching, the total modulation voltage amplitude, the phase difference between the voltage phase and the modulation voltage phase, and the voltage phase are subjected to phase-shift pulse width modulation to obtain the driving signal of the H-bridge converter of each cascade unit.

[0032] In a third aspect, the present application provides a control device for a new energy access railway traction power supply cascade system, which is applied to the new energy access railway traction power supply cascade system, including:

[0033] A control power determination unit is used to perform DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit;

[0034] The drive signal generating unit is used to control the grid-connected current of the H-bridge converter of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtain the drive signal of the H-bridge converter of each cascade unit.

[0035] Furthermore, the control power determination unit includes:

[0036] A reference voltage calculation module is used to independently track the maximum power point of the actual output current and the actual output voltage of the intermediate DC link of each cascade unit through an active bridge DC / DC converter to obtain the output voltage reference value of the maximum power point of each cascade unit;

[0037] An actual voltage determination module, used for inputting the actual value of the output voltage into the notch filter to obtain the actual value of the output voltage after the notch;

[0038] A unit control power determination module, configured to input the difference between the actual value of the output voltage after the notch and the reference value of the output voltage into a PI controller, and then multiply the output signal of the PI controller by the actual value of the output voltage after the notch to obtain the control power of each cascade unit;

[0039] The total control power determination module is used to accumulate the control power of each cascade unit to obtain the total control power.

[0040] Furthermore, the driving signal generating unit comprises:

[0041] A voltage amplitude and phase determination module, used to determine the voltage amplitude and voltage phase of the traction power supply contact network by using a phase-locked loop;

[0042] A phase difference current generating module, used for inputting the current of the traction power supply contact network into a second-order generalized integrator to obtain two currents with the same frequency and amplitude and a phase difference of 90°;

[0043] A component current determination module, used for performing Park transformation on the two currents with the same frequency and amplitude and a phase difference of 90° and the voltage phase, to obtain the d-axis actual value and the q-axis actual value corresponding to the current of the traction power supply overhead line;

[0044] A reference current determination module, used to determine a d-axis reference value corresponding to the current of the traction power supply contact network according to the total control power and the voltage amplitude, and set the q-axis reference value corresponding to the current of the traction power supply contact network to zero;

[0045] A modulation voltage generation module, used for inputting the d-axis actual value, the q-axis actual value, the d-axis reference value and the q-axis reference value into a PI regulator to obtain an active modulation voltage and a reactive modulation voltage;

[0046] A voltage generating module, used for obtaining a phase difference between the voltage phase and the modulation voltage phase and a total modulation voltage amplitude according to the active modulation voltage and the reactive modulation voltage;

[0047] The drive signal generating module is used to perform phase-shift pulse width modulation on the total control power, the control power of each cascade unit, the actual value of the output voltage after notching, the total modulation voltage amplitude, the phase difference between the voltage phase and the modulation voltage phase, and the voltage phase to obtain the drive signal of the H-bridge converter of each cascade unit.

[0048] In a fourth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the control method for accessing the new energy to the railway traction power supply cascade system are implemented.

[0049] In a fifth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for connecting new energy to a railway traction power supply cascade system.

[0050] In a sixth aspect, the present application provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the control method for accessing new energy to a railway traction power supply cascade system.

[0051] In response to the problems in the prior art, the cascade system for accessing new energy to railway traction power supply and its control method and device provided in the present application can realize the integration of photovoltaic power and energy storage power into the railway traction system contact network through the form of cascade H-bridges, replacing the traditional grid-connected form of industrial frequency transformers, reducing the size and weight of the equipment, saving installation space, being clean and environmentally friendly, improving energy conversion efficiency, and improving power quality; it can also comprehensively consider the distribution of renewable energy along the railway, connect the set of new energy equipment to the railway traction system contact network at any point along the railway, reduce the loss of photovoltaic energy caused by long-distance transmission, greatly improve the utilization rate of photovoltaic power, and realize the local consumption of photovoltaic power; in addition, the energy storage device in the set of new energy equipment can not only suppress the secondary pulsation problem of the intermediate DC link of each cascade unit, but also store excess photovoltaic power and train regenerative braking energy, and can achieve peak shaving and valley filling, further improving energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 This is a structural diagram of a cascade system for accessing distributed new energy to railway traction power supply in an embodiment of the present application;

[0054] Figure 2 This is a structural diagram of each unit of the cascade system in an embodiment of the present application;

[0055] Figure 3 A schematic diagram of a system control strategy in an embodiment of the present application;

[0056] Figure 4 This is a flow chart of a control method for connecting new energy to a railway traction power supply cascade system in an embodiment of the present application;

[0057] Figure 5A flow chart for obtaining the control power of each unit in an embodiment of the present application;

[0058] Figure 6 A flow chart of obtaining driving signals of the H-bridge converter of each cascade unit in an embodiment of the present application;

[0059] Figure 7 This is a structural diagram of a control device for accessing a railway traction power supply cascade system with new energy in an embodiment of the present application;

[0060] Figure 8 This is a structural diagram of a control power determination unit in an embodiment of the present application;

[0061] Fig. 9 This is a structural diagram of a driving signal generating unit in an embodiment of the present application;

[0062] Fig.10 It is a schematic diagram of the structure of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0063] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0064] The information collected in the technical solution of this application is information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of relevant data comply with the relevant laws, regulations and standards of relevant countries and regions, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0065] Provide users with corresponding operation entrances for them to choose to agree or reject the automated decision-making results; if the user chooses to reject, the expert decision-making process will be entered.

[0066] In one embodiment, see Figure 1 In order to realize the integration of photovoltaic and energy storage into the contact network of the railway traction system through cascading, replace the traditional grid-connected form of power frequency transformer, improve energy conversion efficiency, and improve power quality, the present application provides a new energy access railway traction power supply cascade system, including: at least one cascade unit; the cascade unit includes a photovoltaic module, an active bridge DC / DC converter, an H-bridge converter, an energy storage DC / DC converter and an energy storage unit;

[0067] Among them, the output positive and negative ports of the photovoltaic module are respectively connected to the positive and negative ports of the input end of the active bridge DC / DC converter; the output port of the active bridge DC / DC converter is connected to the input port of the H-bridge converter; the output positive and negative ports of the energy storage unit are respectively connected to the positive and negative ports of the input end of the energy storage DC / DC converter; the output port of the energy storage DC / DC converter is connected to the input port of the H-bridge converter.

[0068] Understandably, see Figure 1 The cascade system for connecting distributed renewable energy to railway traction power supply provided in this application includes: a traction transformer, a contact network, rails and multiple cascade units. Each cascade unit includes a photovoltaic module, an active bridge DC / DC converter (which can be a single active bridge DC / DC converter, Single Active Bridge, referred to as SAB), an H-bridge converter, an energy storage unit and an energy storage DC / DC converter.

[0069] Among them, the high-voltage side of the traction transformer is connected to the three-phase 110kV system of the State Grid, and the low-voltage side of the traction transformer is connected to the 25kV contact network and rails of the railway traction system.

[0070] The output positive and negative ports of the photovoltaic module are respectively connected to the positive and negative ports of the input end of the single active bridge DC / DC converter, and the output port of the single active bridge DC / DC converter is connected to the input port of the H-bridge converter. The output ports of the H-bridge converters of each cascade unit are connected to the contact network of the railway traction system in series. Among them, the single active bridge DC / DC converter has the maximum power point tracking (MPPT) function to ensure the maximization of the output power of the photovoltaic array, and also has the function of electrical isolation to prevent the reverse transmission of power, thus realizing the one-way transmission of the power generated by the photovoltaic module to the contact network of the railway traction system.

[0071] The output positive and negative ports of the energy storage unit are respectively connected to the positive and negative ports of the input of the energy storage DC / DC converter, and the output port of the energy storage DC / DC converter is connected to the input port of the H-bridge converter. The energy storage unit connected to the intermediate DC link has the ability to suppress the secondary pulsation of the intermediate DC voltage. At the same time, the energy storage unit connection realizes the unidirectional transmission of the electric energy generated by the photovoltaic module to the energy storage unit and the bidirectional transmission of the energy between the railway traction system contact network and the energy storage unit.

[0072] The cascade system for connecting distributed renewable energy to railway traction power supply provided by this application must ensure that each photovoltaic module can independently perform maximum power point tracking to achieve maximum power output. At the same time, the grid-connected current must meet the requirements of the grid-connected specifications to ensure the stability and efficiency of the system. To achieve this goal, this application also provides a control method for the cascade system for connecting distributed renewable energy to railway traction power supply, which is used to accurately control the DC side voltage and grid side current.

[0073] In one embodiment, the active bridge DC / DC converter is a single active bridge DC / DC converter or a dual active bridge DC / DC converter.

[0074] In one embodiment, the single active bridge DC / DC converter comprises: a first bridge arm formed by a first IGBT and a second IGBT connected in series; a second bridge arm formed by a third IGBT and a fourth IGBT connected in series; a third bridge arm formed by a first diode and a second diode connected in series; a fourth bridge arm formed by a third diode and a fourth diode connected in series;

[0075] Among them, the first bridge arm and the second bridge arm are both connected in parallel with the input DC capacitor; the midpoint of the second bridge arm is connected to one end point of the inductor; the other end point of the inductor and the midpoint of the first bridge arm are respectively connected to one end point of the primary winding of the intermediate frequency transformer; the midpoint of the first bridge arm is connected to the other end point of the primary side of the intermediate frequency transformer; the third bridge arm and the fourth bridge arm are connected in parallel with the intermediate DC capacitor; the midpoint of the third bridge arm is connected to one end point of the secondary winding of the intermediate frequency transformer; the midpoint of the fourth bridge arm is connected to the other end point of the secondary winding of the intermediate frequency transformer.

[0076] It can be understood that the cascade system for accessing the distributed new energy to the railway traction power supply provided by the present application includes: a traction transformer, a contact network, rails and a cascade system for accessing the new energy to the railway traction power supply. Among them, the cascade system for accessing the new energy to the railway traction power supply is composed of multiple cascade units connected in series. The overall structural block diagram of the system is shown in FIG. Figure 1 The dotted line indicates that a cascade system for connecting a distributed new energy source to railway traction power supply in an embodiment of the present application can be connected to the railway traction contact network at any point along the railway.

[0077] Each cascade unit of the cascade system for connecting new energy to railway traction power supply includes: photovoltaic components, unidirectional / bidirectional active bridge DC / DC converter, H-bridge converter, energy storage unit and energy storage DC / DC converter. Its structural block diagram is as follows: Figure 2 shown.

[0078] The high-voltage side of the traction transformer is connected to the three-phase 110kV system of the national grid, and the low-voltage side is connected to the 25kV contact network and rails of the railway traction system. Figure 1 shown.

[0079] Among them, the positive and negative output ports of the photovoltaic module are respectively connected to the positive and negative input ports of the single active bridge DC / DC converter as the power source of each system unit, such as Figure 1 shown.

[0080] The output port of the single active bridge DC / DC converter is connected to the intermediate DC capacitor and the input port of the H-bridge converter. By adjusting the pulse width, phase shift angle or switching frequency of the single active bridge DC / DC module, the maximum power point tracking function of the photovoltaic module is realized, the maximum output power of the photovoltaic array is guaranteed, and the voltage stabilization control of the medium voltage DC bus is realized. At the same time, it also has the function of electrical isolation to prevent the reverse transmission of electric energy, and realizes the one-way transmission of the electric energy generated by the photovoltaic module to the contact network of the railway traction system.

[0081] The specific implementation form of the single active bridge DC / DC converter can be but is not limited to a unidirectional active bridge converter, such as Figure 2 As shown. Q1 and Q2 are connected in series to form bridge arm A, Q3 and Q4 are connected in series to form bridge arm B, D1 and D2 are connected in series to form bridge arm C, and D3 and D4 are connected in series to form bridge arm D. Bridge arms A and B are connected in parallel with DC capacitors, the midpoint of bridge arm B is connected to one end of inductor L, the other end of inductor L and the midpoint of bridge arm A are connected to the primary winding of intermediate frequency transformer M respectively, and the midpoint of bridge arm A is connected to the other end of the primary side of intermediate frequency transformer M; bridge arms C and D are connected in parallel with the intermediate DC capacitor, and the midpoints of bridge arms C and D are connected to the secondary winding of intermediate frequency transformer M.

[0082] On the basis of the above scheme, the single active bridge DC / DC converter can also adopt other single-phase or bidirectional DC / DC converters with isolation characteristics, such as a dual active bridge DC / DC converter.

[0083] In one embodiment, the H-bridge converter includes: a fifth bridge arm formed by a fifth IGBT and a sixth IGBT connected in series; and a sixth bridge arm formed by a seventh IGBT and an eighth IGBT connected in series.

[0084] In one embodiment, when there are N cascade units, the midpoint of the sixth bridge arm of the first cascade unit is connected to the traction power supply contact network; the midpoint of the fifth bridge arm of the n-1th cascade unit is connected to the midpoint of the sixth bridge arm of the nth cascade unit; the midpoint of the fifth bridge arm of the Nth cascade unit is connected to the rail; wherein, <n<N。

[0085] It can be understood that the output positive and negative ports of the energy storage unit are connected to the positive and negative ports of the input end of the energy storage DC / DC converter, and the output port of the energy storage DC / DC converter is connected to the intermediate DC capacitor and the input port of the H-bridge converter, such as Figure 2 Among them, the energy storage unit is connected to the intermediate DC link, which has the ability to suppress the secondary pulsation of the intermediate DC voltage. At the same time, the connection of the energy storage unit realizes the unidirectional transmission of the electric energy generated by the photovoltaic module to the energy storage unit, and also realizes the bidirectional transmission of energy between the railway traction system contact network and the energy storage unit.

[0086] On the basis of the above solution, the energy storage DC / DC converter may also adopt other DC / DC converters with bidirectional energy flow, such as a dual active bridge DC / DC converter.

[0087] Multiple H-bridge converters are connected in series to connect photovoltaic (and energy storage) power to the railway traction contact network. By adjusting the pulse width and phase shift angle of the H-bridge converter (for specific adjustment methods, see the control method of the cascade system for connecting new energy to railway traction power supply below), the H-bridge inverter can be operated at unity power factor, thereby ensuring the safe and efficient operation of the power grid and reducing the total harmonic distortion (THD) of the grid current. Figure 1 , Figure 2 As shown, Q5 and Q6 are connected in series to form bridge arm A, Q7 and Q8 are connected in series to form bridge arm B, the midpoint of unit 1 bridge arm B is connected to the contact network, the midpoint of unit 1 bridge arm A is connected to the midpoint of unit 2 bridge arm B, and so on. The midpoint of unit n-1 bridge arm A is connected to the midpoint of unit n bridge arm B, and the midpoint of unit n (the last unit) bridge arm A is connected to the rail.

[0088] From the above description, it can be seen that the cascade system for accessing new energy to railway traction power supply and its control method and device provided in the present application can realize the integration of photovoltaic power and energy storage power into the railway traction system contact network through the form of cascade H-bridge, replacing the traditional grid-connected form of industrial frequency transformer, reducing the volume and weight of the equipment, saving installation space, being clean and environmentally friendly, improving energy conversion efficiency, and improving power quality; it can also comprehensively consider the distribution of renewable energy along the railway, connect the set of new energy equipment to the railway traction system contact network at any point along the railway, reduce the loss of photovoltaic energy caused by long-distance transmission, greatly improve the utilization rate of photovoltaic power, and realize the local consumption of photovoltaic power; in addition, the energy storage device in the set of new energy equipment can not only suppress the secondary pulsation problem of the intermediate DC link of each cascade unit, but also store excess photovoltaic power and train regenerative braking energy, and can achieve peak shaving and valley filling, further improving energy utilization efficiency.

[0089] In one embodiment, see Figure 4In order to realize the integration of photovoltaic and energy storage into the railway traction system contact network through cascade mode, replace the traditional grid-connected form of power frequency transformer, improve energy conversion efficiency, and improve power quality, the present application provides a control method for a new energy access railway traction power supply cascade system, which is applied to the new energy access railway traction power supply cascade system, including:

[0090] S101: performing DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit;

[0091] S102: performing grid-connected current control on the H-bridge converters of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtaining driving signals of the H-bridge converters of each cascade unit.

[0092] It can be understood that the control method of the present invention includes two links: the overall control link and the unit control link. Among them, the overall control link is responsible for controlling the grid-connected current and phase-locking the grid voltage, and the unit control link is responsible for independent MPPT control of the converter in each unit, DC side voltage control, and generating PWM waveforms of the H-bridge switch devices of each unit. The core of the control method is mainly divided into two parts, namely DC voltage control and grid-connected current control.

[0093] ①DC voltage control

[0094] Through a single active bridge DC / DC converter, the output current i of the intermediate DC link of each cascade unit is pvi and the output voltage v pvi Perform independent MPPT control to obtain the output voltage reference value v of the maximum power point of each cascade unit * pvi , v pvi The output voltage after the notch filter is v' pvi . V' pvi and v * pvi The difference is sent to the PI controller, and the output signal of the PI controller is pvi The control power Pi of each cascade unit is obtained by multiplying them. The total control power PT can be obtained by accumulating the control power Pi of each cascade unit. Among them, the trap is to suppress the double frequency harmonic on the DC bus to prevent the third harmonic interference caused by the harmonic to the grid-connected current ig.

[0095] ②Grid-connected current control

[0096] First, the voltage amplitude Um and phase ωt of the traction power supply contact network are obtained through a phase-locked loop. Secondly, the traction power supply contact network current ig is transformed through a second-order generalized integrator (SOGI) to obtain two current waveforms iα and iβ with the same frequency and amplitude and a phase difference of 90°. Among them, iα and iβ have the same frequency and amplitude, and iβ lags iα by 90°. Then, iα, iβ and ωt are substituted into the Park transformation to obtain the components id and iq of the grid-connected current ig on the dq axis. Then, the total control power PT is divided by 0.5 times the grid voltage amplitude Um to obtain the reference value i of ig on the d axis. * d. In order to achieve the unity power factor operation of the inverter, the reference value of the grid-connected current ig on the q axis is i * q can be set to 0. Finally, the reference value is subtracted from the actual value and sent to the PI regulator to finally obtain the active modulation voltage Ud and the reactive modulation voltage Uq. According to Ud and Uq, the phase difference θr between the grid voltage and the modulation voltage and the total modulation voltage amplitude Vr can be obtained. Finally, the total power PT, the power Pi of each cascade unit, and the output voltage v' of each unit are calculated. pvi , the total modulation voltage amplitude Vr, the phase difference θr between the grid voltage and the modulation voltage, and the phase ωt are input into the phase-shift pulse width modulation (PSPWM) module to obtain the driving signal of each cascade unit H bridge.

[0097] From the above description, it can be seen that the cascade system for accessing new energy to railway traction power supply and its control method and device provided in the present application can realize the integration of photovoltaic power and energy storage power into the railway traction system contact network through the form of cascade H-bridge, replacing the traditional grid-connected form of industrial frequency transformer, reducing the volume and weight of the equipment, saving installation space, being clean and environmentally friendly, improving energy conversion efficiency, and improving power quality; it can also comprehensively consider the distribution of renewable energy along the railway, connect the set of new energy equipment to the railway traction system contact network at any point along the railway, reduce the loss of photovoltaic energy caused by long-distance transmission, greatly improve the utilization rate of photovoltaic power, and realize the local consumption of photovoltaic power; in addition, the energy storage device in the set of new energy equipment can not only suppress the secondary pulsation problem of the intermediate DC link of each cascade unit, but also store excess photovoltaic power and train regenerative braking energy, and can achieve peak shaving and valley filling, further improving energy utilization efficiency.

[0098] In one embodiment, see Figure 5 , the output current and output voltage of the active bridge DC / DC converter of each cascade unit are controlled by direct current voltage to obtain the control power of each unit, including:

[0099] S201: performing independent maximum power point tracking control on the actual output current value and the actual output voltage value of the intermediate DC link of each cascade unit through an active bridge DC / DC converter to obtain an output voltage reference value of the maximum power point of each cascade unit;

[0100] S202: Inputting the actual value of the output voltage into a notch filter to obtain the actual value of the output voltage after notching;

[0101] S203: after inputting the difference between the actual value of the output voltage after the notch and the reference value of the output voltage into a PI controller, multiplying the output signal of the PI controller by the actual value of the output voltage after the notch to obtain the control power of each cascade unit;

[0102] S204: Accumulate the control power of each cascade unit to obtain a total control power.

[0103] It is understandable that the cascade system of the distributed new energy access to railway traction power supply of the present invention needs to ensure that each photovoltaic module can independently perform maximum power point tracking to achieve maximum power output. At the same time, the grid-connected current must meet the requirements of the grid-connected specification to ensure the stability and efficiency of the system. To achieve this goal, the embodiment of the present application adopts a control method for the cascade system of the distributed new energy access to railway traction power supply to accurately control the intermediate DC side voltage and the grid side current.

[0104] The DC voltage control is as follows Figure 3 As shown:

[0105] First, the output current i of the intermediate DC link of each unit is sampled. pvi and the output voltage v pvi , through the independent MPPT control of a single active bridge DC / DC converter, the output voltage reference value v of the maximum power point of the DC link between each unit is obtained * pvi , v pvi The output voltage after the notch filter is v' pvi . V' pvi and v * pvi The difference is sent to the PI controller to control the DC side voltage and zero static error. The output signal of the PI controller is the current reference value i i , each unit current reference value i i The corresponding intermediate DC voltage v' pvi Multiply to get the control power P of each unit i , the control power of each unit is accumulated to get the total control power P T The trap is used to suppress the double frequency harmonics on the DC bus and prevent the harmonics from affecting the grid-connected current i gThe third harmonic interference caused by the notch filter is actually a band-stop filter that blocks the signal of the specified frequency from passing through. The notch filter transfer function is:

[0106]

[0107] Where: ω is the frequency to be filtered, f α is the width of the notch filter, and s is the Laplace operator.

[0108] From the above description, it can be seen that the cascade system for accessing new energy to railway traction power supply and its control method and device provided in this application can perform DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit.

[0109] In one embodiment, see Figure 6 , the grid-connected current control of the H-bridge converter of each cascade unit is performed according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and the driving signal of the H-bridge converter of each cascade unit is obtained, including:

[0110] S301: Determine the voltage amplitude and voltage phase of the traction power supply overhead line by using a phase-locked loop;

[0111] S302: Inputting the current of the traction power supply overhead line into a second-order generalized integrator to obtain two currents with the same frequency and amplitude and a phase difference of 90°;

[0112] S303: performing Park transformation on the two currents with the same frequency and amplitude and a phase difference of 90° and the voltage phase to obtain a d-axis actual value and a q-axis actual value corresponding to the current of the traction power supply overhead line;

[0113] S304: determining a d-axis reference value corresponding to the current of the traction power supply contact network according to the total control power and the voltage amplitude, and setting a q-axis reference value corresponding to the current of the traction power supply contact network to zero;

[0114] S305: inputting the d-axis actual value, the q-axis actual value, the d-axis reference value and the q-axis reference value into a PI regulator to obtain an active modulation voltage and a reactive modulation voltage;

[0115] S306: Obtaining a phase difference between the voltage phase and the modulation voltage phase and a total modulation voltage amplitude according to the active modulation voltage and the reactive modulation voltage;

[0116] S307: Perform phase-shift pulse width modulation on the total control power, the control power of each cascade unit, the actual value of the output voltage after notching, the total modulation voltage amplitude, the phase difference between the voltage phase and the modulation voltage phase, and the voltage phase to obtain a driving signal for the H-bridge converter of each cascade unit.

[0117] It is understood that grid-connected current control see Figure 3 First, collect the voltage u of the traction power supply contact network g and traction power supply overhead line current i g , and then the voltage amplitude V of the traction power supply overhead line is obtained through the phase-locked loop PLL m and phase ωt. Secondly, the traction power supply overhead line current i g Through the second-order generalized integrator (SOGI) transformation, two current waveforms with the same frequency and amplitude and a phase difference of 90° are obtained. α ,i β ; where i α with i β The frequency and amplitude are the same, i β Lag α 90°. Then, α ,i β Substituting ωt into the Park transformation, we can get the current i connected to the traction power supply overhead line g The component i on the dq axis d and i q Then divide the total control power PT by 0.5 times the grid voltage amplitude V m You can get i g The reference value i on the d-axis * d , the reference value i * d The current i of the contact network connected to the traction power supply g The component i on the dq axis d After subtraction, the active modulation voltage U is finally obtained through the PI regulator. d In order to achieve the unity power factor operation of the H-bridge converter, the traction power supply overhead line current i g The reference value i on the q axis * q It can be given as 0, and on this basis, the current i g The component i on the dq axis q After subtraction, the reactive modulation voltage U is finally obtained through the PI regulator. q According to U d and U q The total modulation voltage amplitude V r and the phase difference θ r . Vr and θ r It can be calculated as:

[0118]

[0119] Finally, the total power P T , the power P of each unit i , the output voltage v' of each unit pvi , the total modulation voltage amplitude V r , phase difference θ r And the phase ωt is input into the phase-shift pulse width modulation (PSPWM) module to obtain the driving signal Si of each unit H bridge.

[0120]

[0121] From the above description, it can be seen that the cascade system for accessing new energy to railway traction power supply and its control method and device provided in the present application can control the grid-connected current of the H-bridge converter of each cascade unit according to the control power of each cascade unit and the voltage and current of the traction power supply contact network, and obtain the driving signal of the H-bridge converter of each cascade unit.

[0122] Based on the same inventive concept, the embodiment of the present application also provides a control device for a railway traction power supply cascade system accessed with new energy, which can be used to implement the method described in the above embodiment, as described in the following embodiment. Since the principle of solving the problem by the control device for the railway traction power supply cascade system accessed with new energy is similar to the control method for the railway traction power supply cascade system accessed with new energy, the implementation of the control device for the railway traction power supply cascade system accessed with new energy can refer to the implementation of the method based on software performance benchmark determination, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements predetermined functions. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0123] In one embodiment, see Figure 7 In order to realize the integration of photovoltaic and energy storage into the railway traction system contact network through cascade mode, replace the traditional grid-connected form of power frequency transformer, improve energy conversion efficiency, and improve power quality, the present application provides a control device for a new energy access railway traction power supply cascade system, which is applied to the new energy access railway traction power supply cascade system, including:

[0124] A control power determination unit 701 is used to perform DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit;

[0125] The drive signal generating unit 702 is used to control the grid-connected current of the H-bridge converter of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtain the drive signal of the H-bridge converter of each cascade unit.

[0126] In one embodiment, see Figure 8 The control power determination unit 701 includes: a reference voltage calculation module 801, an actual voltage determination module 802, a unit control power determination module 803 and a total control power determination module 804.

[0127] The reference voltage calculation module 801 is used to independently track the maximum power point of the actual output current and the actual output voltage of the intermediate DC link of each cascade unit through an active bridge DC / DC converter to obtain the output voltage reference value of the maximum power point of each cascade unit;

[0128] The actual voltage determination module 802 is used to input the actual value of the output voltage into the notch filter to obtain the actual value of the output voltage after the notch;

[0129] A unit control power determination module 803 is used to input the difference between the actual value of the output voltage after notching and the reference value of the output voltage into a PI controller, and then multiply the output signal of the PI controller by the actual value of the output voltage after notching to obtain the control power of each cascade unit;

[0130] The total control power determination module 804 is used to accumulate the control power of each cascade unit to obtain the total control power.

[0131] In one embodiment, see Fig. 9 The drive signal generating unit 702 includes: a voltage amplitude and phase determining module 901, a phase difference current generating module 902, a component current determining module 903, a reference current determining module 904, a modulation voltage generating module 905, a voltage generating module 906 and a drive signal generating module 907.

[0132] A voltage amplitude and phase determination module 901 is used to determine the voltage amplitude and voltage phase of the traction power supply overhead line by using a phase-locked loop;

[0133] A phase difference current generating module 902 is used to input the current of the traction power supply overhead line into a second-order generalized integrator to obtain two currents with the same frequency and amplitude and a phase difference of 90°;

[0134] The component current determination module 903 is used to perform Park transformation on the two currents with the same frequency and amplitude and a phase difference of 90° and the voltage phase to obtain the d-axis actual value and the q-axis actual value corresponding to the current of the traction power supply overhead line;

[0135] A reference current determination module 904 is used to determine a d-axis reference value corresponding to the current of the traction power supply contact network according to the total control power and the voltage amplitude, and to set a q-axis reference value corresponding to the current of the traction power supply contact network to zero;

[0136] A modulation voltage generating module 905, configured to input the d-axis actual value, the q-axis actual value, the d-axis reference value and the q-axis reference value into a PI regulator to obtain an active modulation voltage and a reactive modulation voltage;

[0137] A voltage generating module 906, configured to obtain a phase difference between the voltage phase and the modulation voltage phase and a total modulation voltage amplitude according to the active modulation voltage and the reactive modulation voltage;

[0138] The drive signal generating module 907 is used to perform phase-shift pulse width modulation on the total control power, the control power of each cascade unit, the actual value of the output voltage after notching, the total modulation voltage amplitude, the phase difference between the voltage phase and the modulation voltage phase, and the voltage phase to obtain the drive signal of the H-bridge converter of each cascade unit.

[0139] From the hardware level, in order to realize the integration of photovoltaic and energy storage into the railway traction system contact network through cascading, replace the traditional grid-connected form of power frequency transformer, improve energy conversion efficiency, and improve power quality, the present application provides an embodiment of an electronic device for realizing all or part of the control method of the new energy access to the railway traction power supply cascade system, and the electronic device specifically includes the following contents:

[0140] Processor, memory, communication interface and bus; wherein the processor, memory and communication interface communicate with each other through the bus; the communication interface is used to realize information transmission between the control device of the new energy access railway traction power supply cascade system and related equipment such as the core business system, user terminal and related database; the logic controller can be a desktop computer, a tablet computer and a mobile terminal, etc., but the present embodiment is not limited thereto. In the present embodiment, the logic controller can be implemented with reference to the embodiment of the control method of the new energy access railway traction power supply cascade system and the embodiment of the control device of the new energy access railway traction power supply cascade system in the embodiment, and the contents thereof are incorporated herein, and the repeated parts are not repeated.

[0141] It is understandable that the user terminal may include a smart phone, a tablet electronic device, a network set-top box, a portable computer, a desktop computer, a personal digital assistant (PDA), a vehicle-mounted device, a smart wearable device, etc. Among them, the smart wearable device may include smart glasses, a smart watch, a smart bracelet, etc.

[0142] In practical applications, part of the control method for connecting new energy to the railway traction power supply cascade system can be executed on the electronic device side as described above, or all operations can be completed in the client device. The specific selection can be based on the processing capability of the client device and the limitations of the user's usage scenario. This application does not limit this. If all operations are completed in the client device, the client device may also include a processor.

[0143] The client device may have a communication module (i.e., a communication unit) that can communicate with a remote server to achieve data transmission with the server. The server may include a server on the task scheduling center side, and other implementation scenarios may also include a server on an intermediate platform, such as a server on a third-party server platform that has a communication link with the task scheduling center server. The server may include a single computer device, or a server cluster consisting of multiple servers, or a server structure of a distributed device.

[0144] Fig.10 FIG. 9 is a schematic block diagram of the system structure of the electronic device 9600 according to an embodiment of the present application. Fig.10 As shown, the electronic device 9600 may include a central processor 9100 and a memory 9140; the memory 9140 is coupled to the central processor 9100. It is worth noting that Fig.10 is exemplary; other types of structures may also be used to supplement or replace this structure to implement telecommunication functions or other functions.

[0145] In one embodiment, the control method function of the new energy access railway traction power supply cascade system can be integrated into the central processor 9100. The central processor 9100 can be configured to perform the following control:

[0146] S101: performing DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit;

[0147] S102: performing grid-connected current control on the H-bridge converters of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtaining driving signals of the H-bridge converters of each cascade unit.

[0148] From the above description, it can be seen that the cascade system for accessing new energy to railway traction power supply and its control method and device provided in the present application can realize the integration of photovoltaic power and energy storage power into the railway traction system contact network through the form of cascade H-bridge, replacing the traditional grid-connected form of industrial frequency transformer, reducing the volume and weight of the equipment, saving installation space, being clean and environmentally friendly, improving energy conversion efficiency, and improving power quality; it can also comprehensively consider the distribution of renewable energy along the railway, connect the set of new energy equipment to the railway traction system contact network at any point along the railway, reduce the loss of photovoltaic energy caused by long-distance transmission, greatly improve the utilization rate of photovoltaic power, and realize the local consumption of photovoltaic power; in addition, the energy storage device in the set of new energy equipment can not only suppress the secondary pulsation problem of the intermediate DC link of each cascade unit, but also store excess photovoltaic power and train regenerative braking energy, and can achieve peak shaving and valley filling, further improving energy utilization efficiency.

[0149] In another embodiment, the control device for the new energy access to the railway traction power supply cascade system can be configured separately from the central processor 9100. For example, the control device for the data composite transmission device new energy access to the railway traction power supply cascade system can be configured as a chip connected to the central processor 9100, and the function of the control method for the new energy access to the railway traction power supply cascade system is realized through the control of the central processor.

[0150] like Fig.10 As shown, the electronic device 9600 may also include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It is worth noting that the electronic device 9600 does not necessarily have to include Fig.10 In addition, the electronic device 9600 may also include Fig.10 For components not shown, reference may be made to the prior art.

[0151] like Fig.10 As shown, the central processing unit 9100 is sometimes also referred to as a controller or an operation control, and may include a microprocessor or other processor device and / or logic device, which receives input and controls the operation of various components of the electronic device 9600.

[0152] The memory 9140 may be, for example, one or more of a cache, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory or other suitable devices. The above-mentioned information related to the failure may be stored, and a program for executing the relevant information may also be stored. The CPU 9100 may execute the program stored in the memory 9140 to implement information storage or processing, etc.

[0153] The input unit 9120 provides input to the central processing unit 9100. The input unit 9120 is, for example, a key or a touch input device. The power supply 9170 is used to provide power to the electronic device 9600. The display 9160 is used to display display objects such as images and texts. The display may be, for example, an LCD display, but is not limited thereto.

[0154] The memory 9140 may be a solid-state memory, such as a read-only memory (ROM), a random access memory (RAM), a SIM card, etc. It may also be a memory that saves information even when the power is off, can be selectively erased, and is provided with more data, examples of which are sometimes referred to as EPROMs, etc. The memory 9140 may also be some other type of device. The memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application / function storage unit 9142, which is used to store application programs and function programs or processes for executing the operation of the electronic device 9600 through the central processor 9100.

[0155] The memory 9140 may also include a data storage unit 9143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 9144 of the memory 9140 may include various drivers for communication functions of the electronic device and / or for executing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0156] The communication module 9110 is a transmitter / receiver that sends and receives signals via the antenna 9111. The communication module (transmitter / receiver) 9110 is coupled to the central processor 9100 to provide input signals and receive output signals, which may be the same as the case of a conventional mobile communication terminal.

[0157] Based on different communication technologies, multiple communication modules 9110 may be provided in the same electronic device, such as a cellular network module, a Bluetooth module and / or a wireless LAN module. The communication module (transmitter / receiver) 9110 is also coupled to a speaker 9131 and a microphone 9132 via an audio processor 9130 to provide an audio output via the speaker 9131 and receive an audio input from the microphone 9132, thereby realizing a common telecommunication function. The audio processor 9130 may include any suitable buffer, decoder, amplifier, etc. In addition, the audio processor 9130 is also coupled to the central processor 9100, so that recording can be performed on the local machine through the microphone 9132, and the sound stored on the local machine can be played through the speaker 9131.

[0158] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all steps in the control method for connecting a new energy source to a railway traction power supply cascade system in the above-mentioned embodiment, where the execution subject is a server or a client. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, all steps in the control method for connecting a new energy source to a railway traction power supply cascade system in the above-mentioned embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0159] S101: performing DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit;

[0160] S102: performing grid-connected current control on the H-bridge converters of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtaining driving signals of the H-bridge converters of each cascade unit.

[0161] From the above description, it can be seen that the cascade system for accessing new energy to railway traction power supply and its control method and device provided in the present application can realize the integration of photovoltaic power and energy storage power into the railway traction system contact network through the form of cascade H-bridge, replacing the traditional grid-connected form of industrial frequency transformer, reducing the volume and weight of the equipment, saving installation space, being clean and environmentally friendly, improving energy conversion efficiency, and improving power quality; it can also comprehensively consider the distribution of renewable energy along the railway, connect the set of new energy equipment to the railway traction system contact network at any point along the railway, reduce the loss of photovoltaic energy caused by long-distance transmission, greatly improve the utilization rate of photovoltaic power, and realize the local consumption of photovoltaic power; in addition, the energy storage device in the set of new energy equipment can not only suppress the secondary pulsation problem of the intermediate DC link of each cascade unit, but also store excess photovoltaic power and train regenerative braking energy, and can achieve peak shaving and valley filling, further improving energy utilization efficiency.

[0162] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0163] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (apparatus), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0164] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0165] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0166] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A new energy access railway traction power supply cascade system, characterized in that: include: At least one cascade unit; the cascade unit includes a photovoltaic module, an active bridge DC / DC converter for DC voltage control, an H-bridge converter for grid-connected current control, an energy storage DC / DC converter and an energy storage unit; Among them, the output positive and negative ports of the photovoltaic module are respectively connected to the positive and negative ports of the input end of the active bridge DC / DC converter; the output port of the active bridge DC / DC converter is connected to the input port of the H-bridge converter; the output positive and negative ports of the energy storage unit are respectively connected to the positive and negative ports of the input end of the energy storage DC / DC converter; the output port of the energy storage DC / DC converter is connected to the input port of the H-bridge converter.

2. The new energy access railway traction power supply cascade system according to claim 1 is characterized in that: The active bridge DC / DC converter is a single active bridge DC / DC converter or a dual active bridge DC / DC converter.

3. The new energy access railway traction power supply cascade system according to claim 2 is characterized in that: The single active bridge DC / DC converter comprises: a first bridge arm formed by a first IGBT and a second IGBT connected in series, a second bridge arm formed by a third IGBT and a fourth IGBT connected in series, a third bridge arm formed by a first diode and a second diode connected in series, and a fourth bridge arm formed by a third diode and a fourth diode connected in series; Among them, the first bridge arm and the second bridge arm are both connected in parallel with the input DC capacitor; the midpoint of the second bridge arm is connected to one end of the inductor; the other end of the inductor and the midpoint of the first bridge arm are respectively connected to one end of the primary winding of the intermediate frequency transformer; the midpoint of the first bridge arm is connected to the other end of the primary side of the intermediate frequency transformer; the third bridge arm and the fourth bridge arm are connected in parallel with the intermediate DC capacitor; the midpoint of the third bridge arm is connected to one end of the secondary winding of the intermediate frequency transformer; the midpoint of the fourth bridge arm is connected to the other end of the secondary winding of the intermediate frequency transformer.

4. The new energy access railway traction power supply cascade system according to claim 1 is characterized in that: The H-bridge converter comprises: a fifth bridge arm formed by a fifth IGBT and a sixth IGBT connected in series; and a sixth bridge arm formed by a seventh IGBT and an eighth IGBT connected in series.

5. The new energy access railway traction power supply cascade system according to claim 4 is characterized in that: When there are N cascade units, the midpoint of the sixth bridge arm of the first cascade unit is connected to the traction power supply contact network; the midpoint of the fifth bridge arm of the n-1th cascade unit is connected to the midpoint of the sixth bridge arm of the nth cascade unit; the midpoint of the fifth bridge arm of the Nth cascade unit is connected to the rail; wherein, <n<N。 6. A control method for a new energy access railway traction power supply cascade system, applied to the new energy access railway traction power supply cascade system according to any one of claims 1 to 5, characterized in that: include: Performing DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit; According to the control power of each cascade unit, the voltage and current of the traction power supply contact network, the grid-connected current of the H-bridge converter of each cascade unit is controlled to obtain the driving signal of the H-bridge converter of each cascade unit.

7. The control method for connecting new energy to the railway traction power supply cascade system according to claim 6 is characterized in that: The output current and output voltage of the active bridge DC / DC converter of each cascade unit are controlled by direct current voltage to obtain the control power of each unit, including: The actual output current value and the actual output voltage value of the intermediate DC link of each cascade unit are independently tracked and controlled by an active bridge DC / DC converter to obtain the output voltage reference value of the maximum power point of each cascade unit; Inputting the actual value of the output voltage into a notch filter to obtain the actual value of the output voltage after notching; After inputting the difference between the actual value of the output voltage after the notch and the reference value of the output voltage into the PI controller, the output signal of the PI controller is multiplied by the actual value of the output voltage after the notch to obtain the control power of each cascade unit; The control power of each cascade unit is accumulated to obtain the total control power.

8. The control method for connecting new energy to the railway traction power supply cascade system according to claim 7 is characterized in that: The method of performing grid-connected current control on the H-bridge converter of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtaining the driving signal of the H-bridge converter of each cascade unit includes: Determining the voltage amplitude and voltage phase of the traction power supply contact network by using a phase-locked loop; Inputting the current of the traction power supply overhead line into a second-order generalized integrator to obtain two currents with the same frequency and amplitude and a phase difference of 90°; Performing Park transformation on the two currents with the same frequency and amplitude and a phase difference of 90° and the voltage phase to obtain the d-axis actual value and the q-axis actual value corresponding to the current of the traction power supply overhead line; Determining a d-axis reference value corresponding to the current of the traction power supply contact network according to the total control power and the voltage amplitude, and setting a q-axis reference value corresponding to the current of the traction power supply contact network to zero; Inputting the d-axis actual value, the q-axis actual value, the d-axis reference value and the q-axis reference value into a PI regulator to obtain an active modulation voltage and a reactive modulation voltage; Obtaining a phase difference between the voltage phase and the modulation voltage phase and a total modulation voltage amplitude according to the active modulation voltage and the reactive modulation voltage; The total control power, the control power of each cascade unit, the actual value of the output voltage after notching, the total modulation voltage amplitude, the phase difference between the voltage phase and the modulation voltage phase, and the voltage phase are subjected to phase-shift pulse width modulation to obtain the driving signal of the H-bridge converter of each cascade unit.

9. A control device for a new energy access railway traction power supply cascade system, applied to the new energy access railway traction power supply cascade system as claimed in any one of claims 1 to 5, characterized in that: include: A control power determination unit is used to perform DC voltage control on the output current and output voltage of the active bridge DC / DC converter of each cascade unit to obtain the control power of each unit; The drive signal generating unit is used to control the grid-connected current of the H-bridge converter of each cascade unit according to the control power of each cascade unit, the voltage and current of the traction power supply contact network, and obtain the drive signal of the H-bridge converter of each cascade unit.

10. The control device for the new energy access railway traction power supply cascade system according to claim 9, characterized in that: The control power determination unit comprises: A reference voltage calculation module is used to independently track the maximum power point of the actual output current and the actual output voltage of the intermediate DC link of each cascade unit through an active bridge DC / DC converter to obtain the output voltage reference value of the maximum power point of each cascade unit; An actual voltage determination module, used for inputting the actual value of the output voltage into the notch filter to obtain the actual value of the output voltage after the notch; A unit control power determination module, configured to input the difference between the actual value of the output voltage after the notch and the reference value of the output voltage into a PI controller, and then multiply the output signal of the PI controller by the actual value of the output voltage after the notch to obtain the control power of each cascade unit; The total control power determination module is used to accumulate the control power of each cascade unit to obtain the total control power.

11. The control device for the new energy access railway traction power supply cascade system according to claim 10, characterized in that: The driving signal generating unit comprises: A voltage amplitude and phase determination module, used to determine the voltage amplitude and voltage phase of the traction power supply contact network by using a phase-locked loop; A phase difference current generating module, used for inputting the current of the traction power supply contact network into a second-order generalized integrator to obtain two currents with the same frequency and amplitude and a phase difference of 90°; A component current determination module, used for performing Park transformation on the two currents with the same frequency and amplitude and a phase difference of 90° and the voltage phase, to obtain the d-axis actual value and the q-axis actual value corresponding to the current of the traction power supply overhead line; A reference current determination module, used to determine a d-axis reference value corresponding to the current of the traction power supply contact network according to the total control power and the voltage amplitude, and set the q-axis reference value corresponding to the current of the traction power supply contact network to zero; A modulation voltage generation module, used for inputting the d-axis actual value, the q-axis actual value, the d-axis reference value and the q-axis reference value into a PI regulator to obtain an active modulation voltage and a reactive modulation voltage; A voltage generating module, used for obtaining a phase difference between the voltage phase and the modulation voltage phase and a total modulation voltage amplitude according to the active modulation voltage and the reactive modulation voltage; The drive signal generating module is used to perform phase-shift pulse width modulation on the total control power, the control power of each cascade unit, the actual value of the output voltage after notching, the total modulation voltage amplitude, the phase difference between the voltage phase and the modulation voltage phase, and the voltage phase to obtain the drive signal of the H-bridge converter of each cascade unit.

12. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the control method for connecting new energy to a railway traction power supply cascade system as described in any one of claims 6 to 8 are implemented.

13. 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 control method for connecting new energy to a railway traction power supply cascade system as described in any one of claims 6 to 8 are implemented.

14. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the control method for connecting new energy to a railway traction power supply cascade system as described in any one of claims 6 to 8 are implemented.

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