Traction power supply comprehensive energy control method

Abstract

The invention discloses a traction power supply integrated energy control method, which is based on a railway traction power supply integrated energy system and comprises a railway energy router, a low-voltage direct-current bus, a power generation source, a direct-current converter, an energy storage device and a controller, a direct-current port of the railway energy router is connected with the low-voltage direct-current bus, an alternating-current side a-phase port is connected with a railway traction power supply a phase, and an alternating-current side b-phase port is connected with a railway traction power supply b phase; the power generation source outputs controllable direct current through the direct-current converter and then is connected to the low-voltage direct-current bus. An energy storage direct-hanging low-voltage direct-current bus; comprising the steps that a controller adopts constant-current closed-loop control on a power generation source based on low-voltage direct-current bus voltage actively clamped by stored energy, it is ensured that the power generation source outputs optimized current through a direct-current converter, a railway energy router is controlled, and power interaction between the power generation source and stored energy and a phase a and a phase b of railway traction power supply is achieved. According to the invention, the problems of integrating renewable new energy and accessing the low-voltage direct-current bus of the railway energy router without DC-DC energy storage are solved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrified railway traction power supply new energy, in particular to a traction power supply comprehensive energy control method. BACKGROUND

[0002] By the end of 2024, the total length of railway in operation in China has reached 162,000 kilometers, of which more than 120,000 kilometers are electrified railways, and the annual energy consumption has broken through 100 billion kWh. For a long time, electrified railways have been highly dependent on public power grids dominated by fossil fuels, and the carbon emissions have been high. Green renewable energy and electrified railway integration, energy storage and recycling of train regenerative braking energy and other technologies have become the development trend of electrified railway technology.

[0003] The existing electrified railway traction power supply system integrates new energy access, recycles train regenerative braking energy through railway energy routers (RER), and at the same time improves the reactive and negative sequence problems of the traction power supply system. In existing research, energy storage needs to access a DC bus with large-capacity inductors and capacitors through a DC-DC, and relies on energy storage DC-DC to control the DC bus voltage, but the energy storage DC-DC and large-capacity inductors and capacitors on the one hand bring device cost problems, and on the other hand reduce system energy efficiency; in addition, the control method provided in existing research mainly focuses on energy management on the system side, and device-level control is not fully considered, and cannot adapt to the operation of energy storage systems without DC-DC. SUMMARY

[0004] In order to solve the above problems, the present application proposes a traction power supply comprehensive energy control method, which effectively solves the technical problems of integrating photovoltaic, wind power and other renewable new energy and accessing railway energy routers low-voltage DC bus without DC-DC energy storage.

[0005] To achieve the above objectives, the technical solution adopted by this invention is: a comprehensive energy control method for traction power supply, based on a comprehensive energy system for railway traction power supply, including a railway energy router (RER), a low-voltage DC bus (LVDB), a generator (PGR), a DC converter (DCC), an energy storage ESS (Energy Storage System), and a controller (CC); the railway energy router (RER) includes a DC port, an AC-side a-phase port, and an AC-side b-phase port, all three ports being capable of bidirectional power flow regulation as needed. The DC port is connected to the low-voltage DC bus (LVDB), the AC-side a-phase port is connected to the railway traction power supply a-phase, and the AC-side b-phase port is connected to the railway traction power supply b-phase; the generator (PGR) outputs controllable DC power through the DC converter (DCC) and is connected to the low-voltage DC bus (LVDB); the energy storage ESS is directly connected to the low-voltage DC bus (LVDB); the signal port of the controller (CC) is connected to the signal terminals of the railway energy router (RER), the generator (PGR), the DC converter (DCC), and the energy storage ESS, respectively, to monitor and analyze traction load operating parameters and control the output of the generator (PGR), the charging and discharging of the energy storage ESS, and the operating status of the railway energy router (RER); including the following steps:

[0006] The controller CC uses the low-voltage DC bus LVDB voltage, which is actively clamped by the energy storage ESS, to implement constant current closed-loop control on the generator PGR. This ensures that the generator PGR outputs optimized current through the DC converter DCC, and controls the railway energy router to achieve power interaction between the generator PGR, the energy storage ESS, and the a and b phases of the railway traction power supply.

[0007] Furthermore, the railway energy router RER adopts a back-to-back structure and includes: single-phase inverter DACa and single-phase inverter DACb. The AC sides of single-phase inverter DACa and single-phase inverter DACb are respectively connected to the a-phase circuit and b-phase circuit of the traction substation or section substation via step-up transformers. The DC sides of single-phase inverter DACa and single-phase inverter DACb are connected in parallel and then connected to the low-voltage DC bus LVDB.

[0008] Furthermore, the railway energy router RER adopts a cross-phase structure, including: a cross-phase single-phase inverter IBI, a traction power supply a-phase reactive power compensation device RPOa, and a traction power supply b-phase reactive power compensation device RPOb. The two AC ports of the cross-phase single-phase inverter IBI are connected to the a-phase circuit and b-phase circuit of the traction substation or section substation via a step-up transformer. The DC side of the cross-phase single-phase inverter IBI is connected to the low-voltage DC bus LVDB.

[0009] Furthermore, the output power P of the power source PGR via the DC-DC converter is determined. PGR The active power P of phase a on the AC side of the railway energy router RER RERa and reactive power Q RERa, the active power P of the b-phase of the railway energy router RER AC side RERb and the reactive power Q RERb , the reference direction of P RERa , Q RERa , P RERb and Q RERb are all towards the railway energy router RER; the voltage V LVDB of the low-voltage DC bus LVDB is actively clamped by the voltage V ESS of the energy storage ESS, that is, V LVDB = V ESS ; the controller CC adopts constant current closed loop control on the power generation source PGR, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, and ensures that the power generation source PGR outputs optimal current through the DC converter DCC:

[0010] Further, when the external public power grid is normally powered, the controller CC adopts constant current closed loop control on the AC side of the railway energy router RER based on the AC side voltage of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER outputs certain forward or reverse current to the railway traction power supply a-phase and b-phase respectively.

[0011] Further, when the external public power grid fails, the railway energy router RER adopts network type control, and the controller CC adopts constant voltage closed loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER maintains the stability of the voltage and frequency of the railway traction power supply a-phase and b-phase, and outputs certain forward or reverse current to the railway traction power supply a-phase and b-phase respectively.

[0012] Further, the railway energy router RER adopts a star structure railway energy router, which comprises a cross-phase single-phase inverter IBI, a static var generator SVGa and a static var generator SVGb, the cross-phase single-phase inverter IBI AC side two ports are connected to the a-phase circuit and the b-phase circuit of the traction substation or substation through a step-up transformer, the AC sides of the static var generator SVGa and the static var generator SVGb are connected to the a-phase circuit and the b-phase circuit of the traction substation or substation respectively, and the DC sides of the cross-phase single-phase inverter IBI, the static var generator SVGa and the static var generator SVGb are all connected in parallel to the low-voltage DC bus LVDB.

[0013] The output power P PGR of the power generation source PGR through the DC converter DCC is determined by the active power P IBIa and the reactive power Q IBIaActive power P and reactive power Q injected by the cross-phase single-phase inverter IBI into the AC side b phase IBIb Active power P and reactive power Q injected by the cross-phase single-phase inverter IBI into the AC side b phase IBIb Active power P and reactive power Q injected by the cross-phase single-phase inverter IBI into the AC side b phase SVGa Active power P and reactive power Q injected by the cross-phase single-phase inverter IBI into the AC side b phase SVGa Active power P and reactive power Q injected by the cross-phase single-phase inverter IBI into the AC side b phase SVGb Active power P and reactive power Q injected by the cross-phase single-phase inverter IBI into the AC side b phase SVGb ;

[0014] Voltage V of the low-voltage DC bus LVDB LVDB Voltage V of the energy storage ESS ESS Active clamping, i.e. V LVDB = V ESS The controller CC adopts constant-current closed-loop control on the AC side of the power generation source PGR, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, and ensures that the power generation source PGR outputs an optimized current through the DC converter DCC:

[0015] When the external public power grid is normally powered, the controller CC adopts constant-current closed-loop control on the AC side of the railway energy router RER based on the voltage of the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER outputs a certain forward or reverse current to the railway traction power supply a phase and b phase respectively;

[0016] When the external public power grid fails, the railway energy router RER adopts network type control, and the controller CC adopts constant-voltage closed-loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER maintains the voltage and frequency stability of the railway traction power supply a phase and b phase, and outputs a certain forward or reverse current to the railway traction power supply a phase and b phase respectively.

[0017] Further, the actual charge and discharge current of the energy storage ESS is:

[0018] I = I c [1 + sin(100Πt)];

[0019] Where I c is the control reference charge and discharge current, and t is time.

[0020] Further, the power generation source PGR includes at least one of photovoltaic, wind power, hydroelectricity, fuel cell, and nuclear power; and the power generation source PGR converts DC or AC power into a DC output adapted to the voltage of the low-voltage DC bus LVDB through the DC converter DCC.

[0021] Further, the energy storage ESS at least includes one of lithium titanate battery, lithium iron phosphate battery, solid-state battery, semi-solid-state battery, and sodium-ion battery; and the energy storage ESS is directly connected to a low-voltage DC bus LVDB, and the working voltage range is adapted to the fluctuation range allowed by the low-voltage DC bus LVDB.

[0022] The beneficial effects of the technical solution are as follows:

[0023] The present application provides a railway traction power supply comprehensive energy system control method based on directly connected energy storage active clamping of low-voltage DC bus voltage, wherein the power generation source adopts constant current closed loop control, and the railway energy router adopts constant current closed loop control when the external public power grid is normally powered and adopts network type constant voltage and constant frequency control when the external public power grid fails, thereby solving the problem that the existing research control method cannot be applied to DC bus without large-capacity inductance and capacitance and energy storage without DC-DC.

[0024] The present application has the advantages of simple structure, easy control, effective access and accommodation of renewable energy along the railway, effective recovery and utilization of train regenerative braking energy, effective management of reactive power, negative sequence current and other power quality problems of the traction power supply system, and meets the urgent needs of low-cost and high-energy-efficient access of new energy and energy storage system of the railway traction power supply. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The present application provides a railway traction power supply comprehensive energy system control method based on directly connected energy storage active clamping of low-voltage DC bus voltage, wherein the power generation source adopts constant current closed loop control, and the railway energy router adopts constant current closed loop control when the external public power grid is normally powered and adopts network type constant voltage and constant frequency control when the external public power grid fails, thereby solving the problem that the existing research control method cannot be applied to DC bus without large-capacity inductance and capacitance and energy storage without DC-DC.

[0026] Figure 2 The present application provides a railway traction power supply comprehensive energy system control method based on directly connected energy storage active clamping of low-voltage DC bus voltage, wherein the power generation source adopts constant current closed loop control, and the railway energy router adopts constant current closed loop control when the external public power grid is normally powered and adopts network type constant voltage and constant frequency control when the external public power grid fails, thereby solving the problem that the existing research control method cannot be applied to DC bus without large-capacity inductance and capacitance and energy storage without DC-DC.

[0027] Figure 3 The present application provides a railway traction power supply comprehensive energy system control method based on directly connected energy storage active clamping of low-voltage DC bus voltage, wherein the power generation source adopts constant current closed loop control, and the railway energy router adopts constant current closed loop control when the external public power grid is normally powered and adopts network type constant voltage and constant frequency control when the external public power grid fails, thereby solving the problem that the existing research control method cannot be applied to DC bus without large-capacity inductance and capacitance and energy storage without DC-DC.

[0028] Figure 4 The present application provides a railway traction power supply comprehensive energy system control method based on directly connected energy storage active clamping of low-voltage DC bus voltage, wherein the power generation source adopts constant current closed loop control, and the railway energy router adopts constant current closed loop control when the external public power grid is normally powered and adopts network type constant voltage and constant frequency control when the external public power grid fails, thereby solving the problem that the existing research control method cannot be applied to DC bus without large-capacity inductance and capacitance and energy storage without DC-DC. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below with reference to the drawings.

[0030] In this embodiment, referring to Figure 1As shown, this invention proposes a comprehensive energy control method for traction power supply, based on a railway traction power supply comprehensive energy system, including a railway energy router (RER), a low-voltage DC bus (LVDB), a generator (PGR), a DC converter (DCC), an energy storage system (ESS), and a controller (CC). The railway energy router (RER) includes a DC port, an AC-side a-phase port, and an AC-side b-phase port. All three ports allow for bidirectional power flow regulation as needed. The DC port is connected to the low-voltage DC bus (LVDB), the AC-side a-phase port is connected to the railway traction power supply a-phase, and the AC-side b-phase port is connected to the railway traction power supply b-phase. The generator (PGR) outputs controllable DC power through the DC converter (DCC) and is connected to the low-voltage DC bus (LVDB). The energy storage system (ESS) is directly connected to the low-voltage DC bus (LVDB). The signal ports of the controller (CC) are connected to the signal terminals of the railway energy router (RER), the generator (PGR), the DC converter (DCC), and the energy storage system (ESS), respectively, to monitor and analyze traction load operating parameters and control the output of the generator (PGR), the charging and discharging of the energy storage system (ESS), and the operating status of the railway energy router (RER). The method includes the following steps:

[0031] The controller CC uses the low-voltage DC bus LVDB voltage, which is actively clamped by the energy storage ESS, to implement constant current closed-loop control on the generator PGR. This ensures that the generator PGR outputs optimized current through the DC converter DCC, and controls the railway energy router to achieve power interaction between the generator PGR, the energy storage ESS, and the a and b phases of the railway traction power supply.

[0032] Specifically, the steps include: determining the output power P of the power source PGR through the DC-DC converter DCC. PGR The active power P of phase a on the AC side of the railway energy router RER RERa and reactive power Q RERa The active power P of phase b on the AC side of the railway energy router RER RERb and reactive power Q RERb P RERa Q RERa P RERb and Q RERb The reference directions are all oriented towards the railway energy router (RER); the voltage V of the low-voltage DC bus (LVDB) is... LVDB The voltage V of the energy storage ESS ESS Active clamping, i.e., V LVDB =V ESS The controller CC employs constant current closed-loop control for the power supply PGR, dynamically adjusting the pulse width modulation duty cycle to drive the switching action of power devices, ensuring that the power supply PGR outputs optimized current through the DC-DC converter DCC.

[0033] When the external public grid is normally powered, the controller CC controls the railway energy router RER based on the AC side voltage of the railway energy router RER, i.e. the railway traction supply a-phase voltage V a and the railway traction supply b-phase voltage V b ; adopts constant current closed loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, so that the railway energy router RER respectively outputs a certain current I a and I b to the railway traction supply a-phase and b-phase, which satisfies the following relationship:

[0034]

[0035] In the formula, and respectively represent the phase difference of the current I a lagging behind the voltage V a and the phase difference of the current I b lagging behind the voltage V b .

[0036] When the external public grid fails, the railway energy router RER adopts network type control, and the controller CC adopts constant voltage closed loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, so that the railway energy router RER maintains the stability of the railway traction supply a-phase and b-phase voltage and frequency, and respectively outputs a certain forward or reverse current to the railway traction supply a-phase and b-phase.

[0037] As an optimization scheme 1 of the above embodiment, as shown in Figure 2 , the railway energy router RER based on the above railway energy router adopts a back-to-back structure, which includes a single-phase inverter DACa and a single-phase inverter DACb. The AC side of the single-phase inverter DACa and the AC side of the single-phase inverter DACb are respectively connected to the a-phase circuit and the b-phase circuit of the traction substation or the substation through the step-up transformer. The DC side of the single-phase inverter DACa and the DC side of the single-phase inverter DACb are connected in parallel and then connected to the low-voltage DC bus LVDB.

[0038] The control method includes the steps of:

[0039] determining the output power P PGR of the power generation source PGR through the DC converter DCC, the active power P RERa and the reactive power Q RERa of the railway energy router RER AC side a-phase, the active power P RERb and the reactive power Q RERb of the railway energy router RER AC side b-phase, P RERa , Q RERa , P RERband Q RERb The reference directions of the railway energy router RER and the low-voltage DC bus LVDB are both towards the railway energy router RER; the voltage V LVDB of the low-voltage DC bus LVDB ESS The active clamping, i.e. V LVDB = V ESS ; the controller CC adopts constant-current closed-loop control on the power generation source PGR, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, and ensures that the power generation source PGR outputs optimized current through the DC converter DCC:

[0040] When the external public power grid is normally powered, the controller CC is based on the AC side voltage of the railway energy router RER, i.e. the railway traction power supply a-phase voltage V a and the railway traction power supply b-phase voltage V b ; adopts constant-current closed-loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, so that the railway energy router RER outputs certain currents I a and I b to the railway traction power supply a-phase and b-phase respectively, which satisfy the following relationship:

[0041]

[0042] In the formula, and respectively represent the phase difference of the current I a lagging behind the voltage V a and the phase difference of the current I b lagging behind the voltage V b .

[0043] When the external public power grid fails, the railway energy router RER adopts network-forming control, and the controller CC adopts constant-voltage closed-loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, so that the railway energy router RER maintains the stability of the railway traction power supply a-phase and b-phase voltage and frequency, and outputs certain forward or reverse currents to the railway traction power supply a-phase and b-phase respectively.

[0044] As an optimization scheme 2 of the above embodiment, as shown in Figure 3 , the railway energy router RER adopts a cross-phase type structure railway energy router, which includes a cross-phase type single-phase inverter IBI, a traction power supply a-phase reactive power compensation device RPOa, and a traction power supply b-phase reactive power compensation device RPOb. The two ports of the AC side of the cross-phase type single-phase inverter IBI are connected to the a-phase circuit and the b-phase circuit of the traction substation or the substation through a step-up transformer, and the DC side of the cross-phase type single-phase inverter IBI is connected to the low-voltage DC bus LVDB.

[0045] The control method comprises the steps of:

[0046] determining the output power P of the power generation source PGR via the DC converter DCC PGR , the active power P and the reactive power Q of the railway energy router RER AC side a phase RERa RERa , the active power P and the reactive power Q of the railway energy router RER AC side b phase RERb RERb , the reference directions of P RERa , Q RERa , P RERb and Q RERb are all towards the railway energy router RER; the voltage V LVDB of the low-voltage DC bus LVDB is actively clamped by the voltage V ESS of the energy storage ESS, i.e. V LVDB = V ESS ; the controller CC adopts constant current closed loop control on the power generation source PGR, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, and ensures that the power generation source PGR outputs the optimal current via the DC converter DCC:

[0047] When the external public power grid is normally powered, the controller CC adopts constant current closed loop control on the AC side of the railway energy router RER based on the railway traction power supply a phase voltage V a and the railway traction power supply b phase voltage V b of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, so that the current I IBI of the cross-phase single-phase inverter IBI meets the following relationship:

[0048]

[0049] In the formula, φ represents the phase difference between the current of the cross-phase inverter IBI and the a phase circuit voltage.

[0050] When the external public power grid fails, the railway energy router RER adopts network-forming control, and the controller CC adopts constant voltage closed loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, so that the railway energy router RER maintains the stability of the railway traction power supply a phase and b phase voltage and frequency, and respectively outputs a certain forward or reverse current to the railway traction power supply a phase and b phase.

[0051] As an optimization scheme 3 of the above embodiment, as Figure 4 ​​As shown, the railway energy router (RER) adopts a star-shaped structure and includes: a cross-phase single-phase inverter (IBI), a static var generator (SVGa), and a static var generator (SVGb). The two AC ports of the cross-phase single-phase inverter IBI are connected to the a-phase circuit and the b-phase circuit of the traction substation or sectioning station via a step-up transformer. The AC sides of the static var generators SVGa and SVGb are respectively connected to the a-phase circuit and the b-phase circuit of the traction substation or sectioning station. The DC sides of the cross-phase single-phase inverter IBI, the static var generator SVGa, and the static var generator SVGb are all connected in parallel to the low-voltage DC bus (LVDB).

[0052] Determine the output power P of the power source PGR through the DC converter DCC. PGR The active power P injected into phase a of the AC side by the IBI of the cross-phase single-phase inverter IBIa and reactive power Q IBIa The active power P injected into the b-phase of the AC side by the IBI of the cross-phase single-phase inverter. IBIb and reactive power Q IBIb The active power P output from the AC side of the static var generator (SVGa) SVGa and reactive power Q SVGa The active power P output from the AC side of the static var generator (SVGb) SVGb and reactive power Q SVGb ;

[0053] The voltage V of the low-voltage DC bus LVDB LVDB The voltage V of the energy storage ESS ESS Active clamping, i.e., V LVDB =V ESS The controller CC employs constant current closed-loop control on the power supply PGR, dynamically adjusting the pulse width modulation duty cycle to drive the switching action of power devices, ensuring that the power supply PGR outputs optimized current through the DC-DC converter DCC.

[0054] When the external public power grid is supplying power normally, the controller CC is based on the AC side voltage of the railway energy router RER, i.e., the a-phase voltage V of the railway traction power supply. a and the voltage of phase b of the railway traction power supply V b A constant current closed-loop control is adopted on the AC side of the railway energy router (RER) to dynamically adjust the pulse width modulation duty cycle and drive the switching action of power devices, thereby increasing the current I of the cross-phase single-phase inverter IBI. IBI Static var generator (SVGa) AC side current I SVGa and the AC side current I of the static var generator SVGb SVGb The following relationship must be satisfied:

[0055]

[0056] In the formula, represents the phase difference of the current hysteresis a-phase circuit voltage of the cross-phase inverter IBI.

[0057] When the external public grid fails, the railway energy router RER adopts grid-forming control, and the controller CC adopts constant voltage closed-loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the power device switch action, so that the railway energy router RER maintains the stability of the railway traction power supply a-phase and b-phase voltage and frequency, and respectively outputs a certain forward or reverse current to the railway traction power supply a-phase and b-phase.

[0058] As an optimization scheme of the above-mentioned various embodiments: the actual charge and discharge current of the energy storage ESS is: I = I c [1+sin(100πt)];

[0059] Where, I c is the control reference charge and discharge current, and t is time.

[0060] So that the energy storage ESS can withstand the double-frequency ripple impact in addition to the charge and discharge current I c required by the controller CC.

[0061] Since the low-voltage DC bus LVDB cancels the large-capacity inductance and capacitance, the energy storage is designed to withstand the double-frequency ripple impact, mainly in two aspects: one is the rate characteristic aspect, and the other is the heat dissipation characteristic aspect. Assuming that the capacity of the two-phase AC side in the railway energy router RER is P a and P b , and the lower limit of the voltage fluctuation range of the low-voltage DC bus LVDB is V low (such as the voltage fluctuation range of the low-voltage DC bus LVDB is designed to be 700-900V, and V low = 700V), then the maximum charge and discharge current of the energy storage ESS is In fact, the energy storage ESS also needs to withstand the double-frequency ripple impact, so the actual charge and discharge current of the energy storage ESS is I max = I c,max [1+sin(100πt)]. When the energy storage ESS is configured with ampere-hours A Ah , then the allowable charge and discharge peak rate of the energy storage ESS is At the same time, the energy storage ESS operates under the maximum charge and discharge current I max condition, and the energy storage ESS must have corresponding heat dissipation capacity to ensure that it works in a reasonable temperature range (such as temperature ≤45℃), and its heat dissipation power can be designed according to the experience of the energy storage thermal management designer, such as calculating the internal resistance RESS , then the maximum heat power P of the energy storage R = I max 2 R ESS .

[0062] Wherein, the power generation source PGR at least includes but is not limited to one of photovoltaic, wind power, hydropower, fuel cell, nuclear power; the power generation source PGR is converted into DC output adapted to the low-voltage DC bus LVDB voltage through the DC converter DCC.

[0063] Wherein, the energy storage ESS at least includes but is not limited to one of lithium titanate battery, lithium iron phosphate battery, solid-state battery, semi-solid-state battery, sodium ion battery; the energy storage ESS is directly connected to the low-voltage DC bus LVDB, and the working voltage range is adapted to the allowable fluctuation range of the low-voltage DC bus LVDB.

[0064] The working principle of the present application is: the railway energy router RER adopts a low-voltage DC bus LVDB (DC bus voltage <1000V, which can be appropriately relaxed to 1500V peak) without large-capacity inductance and capacitance, the energy storage ESS is directly connected to the low-voltage DC bus LVDB without DC-DC, the power generation source PGR is connected to the low-voltage DC bus LVDB after converting DC or AC power into DC output with voltage adaptation through the DC converter DCC, the railway energy router RER contains a DC port, an AC side a-phase port and an AC side b-phase port, the DC port is connected to the low-voltage DC bus LVDB, the AC side a-phase port is connected to the railway traction power supply a-phase, and the AC side b-phase port is connected to the railway traction power supply b-phase, and the three ports are adjusted for bidirectional power flow as needed; the energy storage ESS actively clamps the voltage of the low-voltage DC bus LVDB, the power generation source PGR adopts constant current closed loop control, and the railway energy router adopts constant current closed loop control when the external public grid is normally powered and adopts network type constant voltage and frequency control when the external public grid fails, realizing new energy consumption, brake energy recycling, power quality optimization and emergency power supply guarantee.

[0065] The basic principles and main features of the present application and the advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A traction power supply integrated energy control method, characterized by, The application discloses a railway traction power supply integrated energy system, which comprises a railway energy router RER, a low-voltage direct-current bus LVDB, a power generation source PGR, a direct-current converter DCC, an energy storage ESS and a controller CC. The railway energy router RER comprises a direct-current port, an alternating-current side a-phase port and an alternating-current side b-phase port, all of which are capable of regulating the bidirectional flow of power as required, the direct-current port is connected with the low-voltage direct-current bus LVDB, the alternating-current side a-phase port is connected with a railway traction power supply a-phase, and the alternating-current side b-phase port is connected with a railway traction power supply b-phase. The power generation source PGR is connected with the low-voltage direct-current bus LVDB through the direct-current converter DCC. The energy storage ESS is directly connected with the low-voltage direct-current bus LVDB. The signal port of the controller CC is connected with the signal ports of the railway energy router RER, the power generation source PGR, the direct-current converter DCC and the energy storage ESS, so as to monitor and analyze the traction load operation parameters and control the output of the power generation source PGR, the charging and discharging of the energy storage ESS and the working state of the railway energy router RER. The application discloses a railway traction power supply integrated energy system, which comprises a railway energy router RER, a low-voltage direct-current bus LVDB, a power generation source PGR, a direct-current converter DCC, an energy storage ESS and a controller CC. The railway energy router RER comprises a direct-current port, an alternating-current side a-phase port and an alternating-current side b-phase port, all of which are capable of regulating the bidirectional flow of power as required, the direct-current port is connected with the low-voltage direct-current bus LVDB, the alternating-current side a-phase port is connected with a railway traction power supply a-phase, and the alternating-current side b-phase port is connected with a railway traction power supply b-phase. The power generation source PGR is connected with the low-voltage direct-current bus LVDB through the direct-current converter DCC. The energy storage ESS is directly connected with the low-voltage direct-current bus LVDB. The signal port of the controller CC is connected with the signal ports of the railway energy router RER, the power generation source PGR, the direct-current converter DCC and the energy storage ESS, so as to monitor and analyze the traction load operation parameters and control the output of the power generation source PGR, the charging and discharging of the energy storage ESS and the working state of the railway energy router RER. The controller CC adopts constant current closed loop control on the power generation source PGR based on the low-voltage direct-current bus LVDB voltage actively clamped by the energy storage ESS, ensures that the power generation source PGR outputs optimized current through the direct-current converter DCC, and controls the railway energy router RER, so as to realize the power interaction between the power generation source PGR and the energy storage ESS and the railway traction power supply a-phase and b-phase.

2. The method of claim 1, wherein, The railway energy router RER adopts a back-to-back structure railway energy router, which comprises a single-phase inverter DACa and a single-phase inverter DACb. The alternating-current sides of the single-phase inverters DACa and DACb are respectively connected with a-phase and b-phase circuits of a traction substation or a substation through step-up transformers, and the direct-current sides of the single-phase inverters DACa and DACb are connected in parallel and then connected with the low-voltage direct-current bus LVDB.

3. The method of claim 1, wherein, The railway energy router RER adopts a cross-phase structure railway energy router, which comprises a cross-phase single-phase inverter IBI, a traction power supply a-phase reactive power compensation device RPOa and a traction power supply b-phase reactive power compensation device RPOb. The two alternating-current side ports of the cross-phase single-phase inverter IBI are connected with a-phase and b-phase circuits of a traction substation or a substation through step-up transformers, and the direct-current side of the cross-phase single-phase inverter IBI is connected with the low-voltage direct-current bus LVDB.

4. The integrated energy supply and control method of claim 1-3, wherein, determining the output power P of the power generator PGR via the DC converter DCC PGR , the active power P and the reactive power Q of the railway energy router RER AC side a phase RERa RERa , the active power P and the reactive power Q of the railway energy router RER AC side b phase RERb RERb , the reference directions of P RERa , Q RERa , P RERb and Q RERb are all towards the railway energy router RER; the voltage V LVDB of the low voltage DC bus LVDB is actively clamped by the voltage V ESS of the energy storage ESS, i.e. V LVDB = V ESS ; the controller CC takes constant current closed loop control on the power generator PGR, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, and ensures that the power generator PGR outputs optimal current via the DC converter DCC: ​​ 5. The method of claim 4, wherein, When the external public power grid normally supplies power, the controller CC adopts constant current closed loop control on the alternating-current side of the railway energy router RER based on the alternating-current side voltage of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, and makes the railway energy router RER output certain forward or reverse current to the railway traction power supply a-phase and b-phase respectively.

6. The method of claim 5, wherein, When the external public grid fails, the railway energy router RER adopts network-forming control, the controller CC adopts constant-voltage closed-loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER maintains the voltage and frequency stability of the railway traction power supply a phase and b phase, and outputs certain forward or reverse current to the railway traction power supply a phase and b phase respectively.

7. The method of claim 1, wherein, The railway energy router RER adopts a star-type railway energy router, comprising: a cross-phase single-phase inverter IBI, a static var generator SVGa and a static var generator SVGb, the cross-phase single-phase inverter IBI is connected across the a-phase circuit and the b-phase circuit of the traction substation or substation through a step-up transformer on the AC side, and the AC sides of the static var generator SVGa and the static var generator SVGb are connected to the a-phase circuit and the b-phase circuit of the traction substation or substation respectively, and the DC sides of the cross-phase single-phase inverter IBI, the static var generator SVGa and the static var generator SVGb are connected in parallel to the low-voltage DC bus LVDB; determining the output power P of the power generation source PGR via the direct current converter DCC PGR , the active power P and the reactive power Q injected by the cross-phase single-phase inverter IBI into the a-phase of the alternating current side IBIa IBIa , the active power P and the reactive power Q injected by the cross-phase single-phase inverter IBI into the b-phase of the alternating current side IBIb IBIb , the active power P and the reactive power Q output by the static var generator SVGa on the alternating current side SVGa SVGa , the active power P and the reactive power Q output by the static var generator SVGb on the alternating current side SVGb SVGb ;​​​​ Voltage V of low voltage direct bus LVDB LVDB Voltage V of energy storage ESS ESS Active clamping, i.e. V LVDB = V ESS The controller CC takes constant current closed loop control on the power generation source PGR, dynamically adjusts the pulse width modulation duty cycle, drives the power device switching action, and ensures that the power generation source PGR outputs optimal current through the direct current converter DCC: When the external public grid is normally powered, the controller CC adopts constant-current closed-loop control on the AC side of the railway energy router RER based on the voltage of the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER outputs certain forward or reverse current to the railway traction power supply a phase and b phase respectively; When the external public grid fails, the railway energy router RER adopts network-forming control, the controller CC adopts constant-voltage closed-loop control on the AC side of the railway energy router RER, dynamically adjusts the pulse width modulation duty cycle, drives the switching action of the power device, so that the railway energy router RER maintains the voltage and frequency stability of the railway traction power supply a phase and b phase, and outputs certain forward or reverse current to the railway traction power supply a phase and b phase respectively.

8. The method of claim 1, wherein, The actual charge and discharge current of the energy storage ESS is: I = I c [1 + sin(100πt)]; where I c is the control reference charge and discharge current, t is time.

9. The method of claim 1, wherein, The power generation source PGR at least includes one of photovoltaic, wind power, hydroelectric power, fuel cell and nuclear power; the power generation source PGR converts DC or AC power into DC output adapted to the voltage of the low-voltage DC bus LVDB through the DC converter DCC.

10. The method of claim 1, wherein, The energy storage ESS at least includes one of lithium titanate battery, lithium iron phosphate battery, solid-state battery, semi-solid-state battery and sodium ion battery; the energy storage ESS is directly connected to the low-voltage DC bus LVDB, and the working voltage range is adapted to the allowable fluctuation range of the low-voltage DC bus LVDB.

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