Station-level modeling method for large-scale vehicle network interaction

Abstract

The invention provides a station-level modeling method for large-scale vehicle network interaction, which comprises the following steps: 1) constructing an electromagnetic transient simulation model library in a station-level simulation device for large-scale vehicle network interaction, the electromagnetic transient simulation model library comprising a binary resistance model, an average value model and a constant admittance model; 2) constructing a charging and discharging motor model suitable for the charging and discharging process of the electric vehicle, wherein the charging and discharging motor model is formed based on a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter; 3) based on the electromagnetic transient simulation model library and the charging and discharging machine model, establishing a large-scale vehicle-network interaction station-level digital simulation system, constructing a large-scale vehicle-network interaction station-level model, and connecting all charging piles in parallel to a power grid node by adopting a common alternating current bus framework to realize simulation of a dynamic interaction process in a large-scale electric vehicle grid-connected scene; the problem that an existing vehicle network interactive simulation model cannot accurately simulate electrical coupling and impedance interaction generated during parallel operation of multiple charging piles under a station-level scale is solved.

Description

TECHNICAL FIELD

[0001] The application relates to a station-level modeling method for large-scale vehicle-to-grid interaction, and belongs to the technical field of digital simulation of power systems. BACKGROUND

[0002] With the rapid increase of the popularization rate of electric vehicles, as a key node connecting vehicles and power grids, the large-scale and clustered development trend of charging stations poses new challenges to the planning and operation of distribution networks; a single charging station contains multiple charging piles operating in parallel, forming a station-level system with complex power electronic interaction characteristics; the dynamic behavior of the station-level system, especially the coordinated operation of a large number of converters under the common AC bus, has a significant impact on the power quality, load characteristics and system stability of the local power grid.

[0003] At present, in the research on vehicle-to-grid interaction, the granularity of simulation modeling is mostly at the level of a single charging pile or a single vehicle battery; although such models can depict the characteristics of a single element, they cannot accurately reflect the overall effects such as electrical coupling, impedance interaction and coordinated control of multiple piles operating in parallel at the station level; due to the lack of a specialized station-level fine simulation model, it is difficult to accurately evaluate the overall access characteristics of the charging station, the internal dynamic process and its impact on the distribution network, so as to effectively support the optimized operation of the charging station and the coordinated scheduling with the power grid.

[0004] Therefore, developing a station-level fine modeling method that can accurately describe the coupling relationship of multiple devices inside the charging station and is suitable for large-scale scenarios has become a key prerequisite for accurately analyzing the impact of vehicle-to-grid interaction, tapping the potential of electric vehicle cluster regulation, and ensuring the safe and stable operation of the distribution system. SUMMARY

[0005] The application provides a station-level modeling method for large-scale vehicle-to-grid interaction, which aims to solve the problem of insufficient granularity of existing vehicle-to-grid interaction simulation models and the inability to accurately simulate the electrical coupling and impedance interaction of multiple charging piles operating in parallel at the station level.

[0006] The technical solution of the application is a station-level modeling method for large-scale vehicle-to-grid interaction, which comprises the following steps:

[0007] Step 1) Constructing an electromagnetic transient simulation model library in a station-level simulation device for large-scale vehicle-to-grid interaction, including a binary resistance model, an average value model and a constant admittance model;

[0008] Step 2) Constructing a charging and discharging machine model suitable for the charging and discharging process of electric vehicles, wherein the charging and discharging machine model is based on a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter;

[0009] Step 3) Based on the electromagnetic transient simulation model library and the charging and discharging machine model, a large-scale vehicle-to-grid interaction station-level digital simulation system is established, a large-scale vehicle-to-grid interaction station-level model is constructed, all charging piles are connected in parallel to the power grid node using a common AC bus architecture, and the dynamic interaction process in the large-scale electric vehicle grid-connected scenario is simulated.

[0010] Further, the step of constructing the electromagnetic transient simulation model library specifically includes:

[0011] Firstly, based on the topology structure of the power electronic converter, a binary resistance model for system-level stability rapid screening and an average value model for control loop dynamic characteristic analysis are respectively established using a switching modeling method;

[0012] Then, the switching model is discretized using the backward Euler method, and a constant admittance model is constructed to replace the computationally intensive detailed switching model; the constant admittance model establishes the equivalent admittance expression of the switching device in the on and off states by introducing a historical current source term, thereby representing the steady-state and transient external characteristics of the converter;

[0013] Finally, the binary resistance model, the average value model and the constant admittance model are integrated to form a multi-granularity electromagnetic transient simulation model library.

[0014] Further, the construction process of the electromagnetic transient simulation model library includes:

[0015] Step 1-1) Based on the topology structure and working principle of the power electronic converter, combined with switching modeling, numerical discretization, linear interpolation and error compensation, a multi-granularity electromagnetic transient simulation model library including binary resistance model, average value model and constant admittance model is established, which provides basic modeling elements for the establishment of electric vehicle battery model and power grid system model;

[0016] Step 1-2) Based on the electromagnetic transient simulation model library, an electric vehicle battery model and a power grid system model are constructed.

[0017] Further, according to the binary resistance model, the switching device is simplified by defining two extreme impedance states: when the switch is on, it is equivalent to a small resistance; when the switch is off, it is equivalent to a large resistance; the equivalent conductance of the binary resistance model switches accordingly and is suitable for system-level stability rapid judgment, and the expression of the binary resistance model is:

[0018] ;

[0019] In the formula, is the equivalent conductance of the switch under the binary resistance model; is the small equivalent resistance when the switch is on; is the large equivalent resistance when the switch is off;

[0020] According to the average value model, the fluctuating voltage and current variables in the switching period are replaced by their periodic average values, and a circuit model equivalent to the external characteristic is constructed through a controlled source as an interface. Taking the voltage source type converter topology as an example, the average value model expression in the dq rotating coordinate is:

[0021] ;

[0022] In the formula, 、 、 is the input current in the dq rotating coordinate; 、 、 is the input voltage in the dq rotating coordinate; is the output voltage; 、 is the equivalent impedance of the input end of the voltage source type converter; is the included angle between the three-phase stationary coordinate (abc) and the dq rotating coordinate; M is the modulation ratio; is the rotation angular velocity of the two-phase dq rotating coordinate system; the average value model is applicable to the scenario analysis in which the control loop bandwidth is much lower than the switching frequency;

[0023] According to the constant admittance model, a small inductance and a small capacitance are used as equivalent elements to replace the on and off state switches. The constant admittance model is based on the backward Euler discretization method, and a parameter equation of the switching branch is established:

[0024] ;

[0025] In the formula, represents the branch voltage; represents the branch current; represents a moment; and respectively represent the historical current sources in the on and off states; is the equivalent admittance when the switch is off; is a damping resistance in series; represents the time step;

[0026] A dynamic historical current compensation term is introduced to match the transient response of the ideal switch and the actual admittance model. The expression of the historical current source after introducing the dynamic historical current compensation term is:

[0027] ;

[0028] In the formula, and respectively represent the historical current sources in the on and off states after the dynamic historical current compensation term is introduced; represents the branch voltage; represents the branch current; , respectively represent the voltage coefficient and the current coefficient in the on state; , represent the voltage coefficient and the current coefficient in the off state; is the equivalent admittance when the switch is on; represents a moment in time; represents a time step.

[0029] Further, according to the electric vehicle battery model, the non-linear external characteristics and dynamic response process of the electric vehicle battery are simulated by a programmable direct current power supply, and the accurate management and control of the charging and discharging power are realized through the controllable bidirectional DC / DC converter designed in the charging and discharging machine model;

[0030] According to the power grid system model, all charging piles in the station adopt the connection mode of "common AC bus", which is connected in parallel to the power grid node through a shared AC bus, truly simulates the typical topological structure of large-scale electric vehicle charging facilities accessing the power grid, analyzes and evaluates the influence of large-scale load on the power grid, and supports the orderly grid connection of large-scale electric vehicles;

[0031] According to the simulation requirements, the binary resistance model is selected from the electromagnetic transient simulation model library for system-level stability preliminary judgment, the average value model is used for control loop optimization, and the constant admittance model is used for accurate analysis of electromagnetic transient characteristics, so as to provide a balance between accuracy and efficiency for different application scenarios.

[0032] Further, the specific process of constructing the charging and discharging machine model includes the following steps:

[0033] Step 2-1) Establish a mathematical model of a three-phase voltage type PWM rectifier, define the positive direction convention of the instantaneous voltage and the instantaneous current, describe the on-off state of the rectifier bridge arm of the three-phase voltage type PWM rectifier based on the switching function, and derive the dynamic relationship equation of the AC side voltage and current according to Kirchhoff's voltage law;

[0034] Step 2-2) Coordinate transformation and decoupling control, the mathematical model of the three-phase voltage type PWM rectifier in the three-phase stationary coordinate system is converted to the two-phase stationary coordinate system and the two-phase rotating coordinate system through coordinate transformation, realizing independent control of active current and reactive current;

[0035] Step 2-3) Design the operation control strategy of the charge-discharge machine model, and determine the double closed-loop control strategy of the three-phase voltage type PWM rectifier composed of voltage outer loop and current inner loop and the constant power control strategy of the bidirectional DC / DC converter according to the rectification state and the inversion state of the charge-discharge machine model in grid-connected operation, so as to realize the preset charge-discharge power target;

[0036] Step 2-4) Construct the control model of the bidirectional DC / DC converter, select the switching model of the power electronic converter according to the demand based on the electromagnetic transient simulation model library; the control model of the bidirectional DC / DC converter can dynamically adjust the duty cycle of the power switching device according to the charge-discharge demand of the electric vehicle battery, so as to control the voltage level output to the DC bus.

[0037] Further, the positive direction expression of the instantaneous voltage and the instantaneous current is:

[0038] ;

[0039] In the formula, 、 、 is the grid voltage; is the reference voltage of the electric N;

[0040] The switching function of the rectifier bridge arm of the three-phase voltage type PWM rectifier is:

[0041] ;

[0042] In the formula, indicates the switching state of the k phase of the three-phase voltage type PWM rectifier;

[0043] According to Kirchhoff's voltage law, taking the inductor current and the capacitor voltage as state variables, the following equation can be obtained:

[0044] ;

[0045] In the formula, 、 、 is the alternating current input; 、 、 is the grid voltage; is the DC side load current; 、 、 and are the voltage values of points A, B, C and O to the reference point N; is the DC bus voltage; is the AC side inductor; is the filter capacitor; Rload is the equivalent resistance of the load on the DC side; Rload is the equivalent resistance of the load on the DC side; Vdc is the equivalent voltage of the load on the DC side;

[0046] According to the three-phase balance principle of the main circuit, the following expression can be obtained:

[0047] ;

[0048] In the formula, Von is the voltage value from point O to reference point N; Vdc is the DC bus voltage; , , S a, S b and S c are the switching states of the a, b and c phases of the three-phase voltage type PWM rectifier respectively, when the value is 1, it indicates that the upper bridge arm of the phase is turned on and the lower bridge arm is turned off; when the value is 0, it indicates that the upper bridge arm of the phase is turned off and the lower bridge arm is turned on;

[0049] The coordinate transformation in step 2-2 is to simplify the decoupling control design, which maps the three-phase stationary coordinate system abc to the two-phase stationary coordinate system and the two-phase rotating coordinate system dq;

[0050] The mathematical model expression of the three-phase voltage type PWM rectifier in the three-phase stationary coordinate system (abc) is:

[0051] ;

[0052] In the formula, , , I a, I b and I c are the AC input currents; , , V a, V b and V c are the grid voltages; , , S a, S b and S c are the switching states of the a, b and c phases of the three-phase voltage type PWM rectifier respectively; ; Vdc is the DC bus voltage; L is the AC side inductance; C is the filter capacitance; Rload is the equivalent resistance of the load on the DC side; Rload is the equivalent resistance of the load on the DC side; Vdc is the equivalent voltage of the load on the DC side;

[0053] The mathematical model of the main circuit in the two-phase stationary coordinate system is as follows:

[0054] ;

[0055] In the formula, , for two-phase grid-side voltage in stationary coordinate system; , for two-phase grid-side current in stationary coordinate system; , for two-phase bridge wall turn-on and turn-off signal in stationary coordinate system; DC bus voltage; AC side inductance; filter capacitance; loop equivalent resistance; DC side load equivalent resistance; DC side load equivalent voltage.

[0056] The mathematical model of the main circuit in the dq rotating coordinate system is:

[0057] ;

[0058] In the formula, , for two-phase dq rotating coordinate system grid-side voltage; , for two-phase rotating coordinate system grid-side current; , for two-phase dq rotating coordinate system bridge wall turn-on and turn-off signal; rotating angular velocity of two-phase dq rotating coordinate system; DC bus voltage; AC side inductance; filter capacitance; loop equivalent resistance; DC side load equivalent resistance; DC side load equivalent voltage.

[0059] Further, the operation control strategy of the three-phase voltage type PWM rectifier in step 2-3), when the charge-discharge machine model is in the rectification state, the three-phase voltage type PWM rectifier adopts double closed loop control of voltage outer ring and current inner ring; when the charge-discharge machine model is in the inversion state, the bidirectional DC / DC converter adopts constant power control strategy for grid connection, taking the grid frequency and voltage as the regulation basis;

[0060] Step 2-4) The control model of the bidirectional DC / DC converter selects the switching model of the power electronic converter according to the demand. When the battery is charging, the bidirectional DC / DC converter VT1 is in the switching state, and VT2 is in the constant-off state, and the output voltage expression is:

[0061] ;

[0062] wherein, is the input voltage; is the output voltage; is the duty cycle; is the switching period; is the turn-on time;

[0063] When the battery is discharging, the bidirectional DC / DC converter VT1 is in a constant-off state, and VT2 is in a switching state, and the output voltage expression is:

[0064] ;

[0065] wherein, is the input voltage; is the output voltage; is the duty cycle; is the switching period; is the turn-off time.

[0066] Further, the establishment of the large-scale vehicle-to-grid interaction station-level model in step 3) specifically comprises:

[0067] Step 3-1) establishing a charge-discharge machine model for a single electric vehicle charging pile, wherein: in the charging mode, the alternating current of the power grid is converted into direct current through a three-phase voltage type PWM rectifier and a PQ control strategy, and then the electric vehicle battery is charged through a bidirectional DC / DC converter; and in the discharging mode, when there is a power shortage in the power grid, the electric vehicle battery energy is boosted through the bidirectional DC / DC converter, and then converted into alternating current that meets the requirements of the power grid by the three-phase voltage type PWM rectifier and fed back to the power grid;

[0068] Step 3-2) integrating the electromagnetic transient simulation model library and the charge-discharge machine model to construct a charging pile cluster cooperative response model, which is used to simulate the application scenarios of multiple electric vehicles simultaneously charging or participating in vehicle-to-grid energy return, and each charging pile is connected in parallel through a common alternating current bus structure and connected to the same power grid access point;

[0069] Step 3-3) using the large-scale vehicle-to-grid interaction station-level digital simulation system to evaluate the influence of the large-scale electric vehicle cluster access on the transient stability level and dynamic operation characteristics of the power system, quantitatively analyze the contribution of the large-scale vehicle-to-grid interaction station-level model to improving the vehicle-to-grid interaction capability, and verify the effectiveness of the large-scale vehicle-to-grid interaction station-level model in supporting the orderly grid connection and coordinated control of large-scale electric vehicles.

[0070] Further, the large-scale vehicle-to-grid interaction station-level simulation device comprises:

[0071] The hardware component employs high-level integrated technology to design the core computing module of a large-scale vehicle-to-network interactive station-level digital simulation system. It designs the hardware architecture of the station-level simulation device for large-scale vehicle-to-network interaction, proposing a core computing unit, input / output unit, and data interaction bus for real-time simulation. This includes a multi-core parallel simulation solution unit with dedicated simulation modules, a network switch, analog input modules, analog output modules, and a host computer.

[0072] The software component is a large-scale vehicle-grid interactive station-level digital simulation system that includes an electromagnetic transient simulation model library, an electric vehicle battery model, a power grid system model, and a charge / discharge machine model. This large-scale vehicle-grid interactive station-level digital simulation system is developed using industrial-grade C++ and adopts the Linux+RT embedded real-time operating system. It integrates and applies a hybrid modeling framework, multi-timescale dynamic simulation algorithms, multi-model switching and automatic variable step size, sparse matrix solving, multi-core parallel computing, and power information hybridization.

[0073] The beneficial effects of this invention are:

[0074] 1) This invention solves the problem of insufficient granularity in existing vehicle-to-grid interaction simulation models, and solves the problem of being unable to accurately simulate the complex overall effects such as electrical coupling and impedance interaction generated when multiple charging piles are connected in parallel at the site level;

[0075] 2) This invention effectively improves the simulation accuracy and modeling flexibility of large-scale vehicle-to-grid interactive systems by constructing a multi-granular electromagnetic transient simulation model library and combining it with a charge / discharge machine model based on a three-phase voltage-source PWM rectifier and a bidirectional DC / DC converter.

[0076] 3) Through further design, this invention integrates a large-scale vehicle-to-grid interaction site-level model using a common AC bus architecture, thereby achieving accurate simulation and system performance evaluation of the dynamic interaction process under large-scale electric vehicle grid connection scenarios, significantly enhancing the transient stability and overall operational reliability of the vehicle-to-grid interaction system. Attached Figure Description

[0077] Appendix Figure 1 A schematic diagram of the overall process for a site-level modeling method for large-scale vehicle-to-grid interaction.

[0078] Appendix Figure 2 A schematic diagram illustrating the method for establishing a constant admittance model for power electronic converters.

[0079] Appendix Figure 3 This is a schematic diagram of the control strategy for the charge / discharge machine model.

[0080] Appendix Figure 4 This is a schematic diagram of a three-phase voltage-type PWM rectifier in a charge / discharge machine model.

[0081] AppendixFigure 5 The constant admittance model schematic diagram of the bidirectional DC / DC converter in the charging and discharging machine model.

[0082] The Figure 6 The simulation structure of the grid connection of the large-scale electric vehicle station taking the grid connection of five electric vehicle charging piles as an example.

[0083] The Figure 7 The active power simulation waveform of the station-level charging station under the condition that the charging pile end is 35kV and the main grid is 220kV.

[0084] The Figure 8 The reactive power simulation waveform of the station-level charging station under the condition that the charging pile end is 35kV and the main grid is 220kV.

[0085] The Figure 9 The module structure schematic diagram of the station-level simulation device of the large-scale vehicle-to-grid interaction. DETAILED DESCRIPTION

[0086] The technical solutions of the present application will be described clearly and completely in combination with the drawings and specific embodiments.

[0087] As shown in the Figure 1 The method comprises the following steps:

[0088] Step 1) Construct an electromagnetic transient simulation model library in the self-designed station-level simulation device of the large-scale vehicle-to-grid interaction, which contains a binary resistance model, an average value model and a constant admittance model, can meet the charging and discharging requirements of different application scenarios, and provides a basis for subsequent models of electric vehicle batteries, charging and discharging machines, power grid systems and the like;

[0089] Step 2) Construct a charging and discharging machine model suitable for the charging and discharging process of an electric vehicle, which is composed of a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter, realizes integrated operation of rectification and inversion functions through coordinated control, and effectively improves the DC voltage utilization rate and control accuracy;

[0090] Step 3) Based on the electromagnetic transient simulation model library and the charging and discharging machine model, establish a large-scale vehicle-to-grid station-level digital simulation system, which can construct a large-scale vehicle-to-grid station-level model, adopt a common AC bus architecture to connect all charging piles in parallel to a grid node, and realize simulation of the dynamic interaction process under the large-scale electric vehicle grid connection scenario; the large-scale vehicle-to-grid station-level digital simulation system can also perform model editing, parameter configuration, fault setting, simulation recording, network decoupling, multi-rate simulation data interaction and the like.

[0091] The application meets the charging and discharging requirements of different application scenarios by constructing an electromagnetic transient simulation model library containing a binary resistance model, an average value model and a constant admittance model; a charging and discharging machine model suitable for the charging and discharging process of an electric vehicle is developed to realize efficient rectification and inversion control and improve the energy conversion efficiency in the charging and discharging process; on this basis, a large-scale vehicle-to-grid interactive station level digital simulation system is established, a large-scale vehicle-to-grid interactive station level model is constructed, all charging piles in the station are connected in parallel to the power grid node by adopting a common AC bus architecture, and the simulation of the dynamic interaction process under the large-scale electric vehicle grid-connected scenario is realized; the application effectively enhances the transient stability and overall operation reliability of the large-scale vehicle-to-grid interactive station level model; and the self-designed large-scale vehicle-to-grid interactive station level simulation device is used to realize the above method.

[0092] The application effectively improves the simulation accuracy and modeling flexibility of the large-scale vehicle-to-grid interactive station level model by constructing a multi-granularity electromagnetic transient simulation model library and combining a charging and discharging machine model based on a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter; further, by adopting a common AC bus architecture to simulate the dynamic interaction process under the large-scale electric vehicle grid-connected scenario in the large-scale vehicle-to-grid interactive station level digital simulation system, the transient stability and overall operation reliability of the large-scale vehicle-to-grid interactive station level model are significantly enhanced.

[0093] Further, the construction of the electromagnetic transient simulation model library is realized according to the following steps:

[0094] Firstly, based on the topology structure of the power electronic converter, a binary resistance model for system level stability rapid screening and an average value model for control loop dynamic characteristic analysis are respectively established by adopting a switching modeling method;

[0095] Then, in order to meet the balance requirement of precision and efficiency of electromagnetic transient simulation, a backward Euler method is adopted to discretize the switching model, a constant admittance model is constructed to replace the calculation-intensive detailed switching model; the constant admittance model establishes the equivalent admittance expression of the switching device in the on and off states by introducing a historical current source term, so as to represent the steady-state and transient-state external characteristics of the converter;

[0096] Finally, the binary resistance model, the average value model and the constant admittance model are integrated to form a multi-granularity electromagnetic transient simulation model library, which provides a model selection basis for different simulation application scenarios.

[0097] The construction process of the electromagnetic transient simulation model library includes the following steps:

[0098] Step 1-1) Based on the topology and working principle of power electronic converter, combined with switch modeling, numerical discretization, linear interpolation and error compensation, a multi-granularity electromagnetic transient simulation model library is established, including binary resistance model, average value model and constant admittance model, which provides basic modeling elements for the establishment of electric vehicle battery model and power grid system model.

[0099] Step 1-2) Based on the electromagnetic transient simulation model library, the electric vehicle battery model and the power grid system model are constructed; according to different needs, one of the three switch models in the electromagnetic transient simulation model library is used to replace the ideal model in the traditional electric vehicle battery and power grid system model.

[0100] According to step 1-1), the binary resistance model is simplified by defining two extreme impedance states of the switch device: when the switch is on, it is equivalent to a small resistance; when the switch is off, it is equivalent to a large resistance; the equivalent conductance of the binary resistance model is switched accordingly, which is suitable for fast judgment of system stability, and the expression of the binary resistance model is:

[0101] ;

[0102] In the formula, is the equivalent conductance of the switch under the binary resistance model; is the minimum equivalent resistance when the switch is on; is the maximum equivalent resistance when the switch is off.

[0103] According to step 1-1), the average value model adopts the averaging method in continuous time domain, replaces the pulsating voltage and current variables in the switch period with their period average values, and through the controlled source as the interface, constitutes the circuit model with equivalent external characteristics; taking the voltage source type converter topology as an example, the average value model expression in dq rotating coordinates is:

[0104] ;

[0105] In the formula, , , is the input current in dq rotating coordinates; , , is the input voltage in dq rotating coordinates; is the output voltage; , is the equivalent impedance of the input end of the voltage source type converter; is the angle between three-phase stationary coordinates (abc) and dq rotating coordinates; M is the modulation ratio; is the rotational angular velocity of two-phase dq rotating coordinate system; the average value model is suitable for the scenario analysis of control loop bandwidth far lower than switching frequency.

[0106] The constant admittance model in step 1-1) is equivalent to small inductance and small capacitance, and is equivalent to replace the on and off state switches, as shown in the accompanying drawings. Figure 2 The constant admittance model is based on the backward Euler discretization method to establish the parameter equation of the switching branch:

[0107] ;

[0108] In the formula, represents the branch voltage; represents the branch current; represents a certain time; and respectively represent the historical current source in the on and off states; is the equivalent admittance when the switch is off; is a damping resistance in series; represents the time step.

[0109] The dynamic history current compensation term is introduced to match the transient response of the ideal switch and the actual admittance model, and the expression of the historical current source after introducing the dynamic history current compensation term is:

[0110] ;

[0111] In the formula, and respectively represent the historical current source in the on and off states after introducing the dynamic history current compensation term; represents the branch voltage; represents the branch current; , are the voltage coefficient and the current coefficient in the on state, respectively; , are the voltage coefficient and the current coefficient in the off state, respectively; is the equivalent admittance when the switch is on; represents a certain time; represents the time step.

[0112] According to the electric vehicle battery model in step 1-2), the non-linear external characteristics and dynamic response process of the electric vehicle battery are simulated by a simple programmable DC power supply, and the accurate management and control of the charging and discharging power are realized through the controllable bidirectional DC / DC converter designed in the charging and discharging machine model;

[0113] According to the power grid system model in step 1-2), all charging piles in the station adopt the connection mode of "common AC bus", and are connected in parallel to the power grid node through a shared AC bus,

[0114] The typical topology structure of the real simulation of the centralized access of large-scale electric vehicle charging facilities to the power grid is simulated, the influence of large-scale load on the power grid is analyzed and evaluated, the orderly grid connection of large-scale electric vehicles is supported, and the transient stability and overall operation reliability of vehicle-grid interaction are improved.

[0115] For the precision adaptation level of the three switch models of the power electronic converter in the electromagnetic transient simulation model library, according to the simulation requirements, the binary resistance model is selected in the electromagnetic transient simulation model library for system-level stability preliminary judgment, the average value model is used for control loop optimization, and the constant admittance model is used for accurate analysis of electromagnetic transient characteristics, to provide a balance between precision and efficiency for different application scenarios.

[0116] The specific process of constructing the charging and discharging machine model includes the following steps:

[0117] Step 2-1) Establish a mathematical model of the three-phase voltage PWM rectifier, clearly define the positive direction convention of the system instantaneous voltage and instantaneous current, and describe the on-off state of the rectifier bridge arm of the three-phase voltage PWM rectifier based on the switching function, and derive the dynamic relationship equation of the AC side voltage and current according to Kirchhoff's voltage law;

[0118] Step 2-2) Coordinate transformation and decoupling control, the mathematical model of the three-phase voltage PWM rectifier in the three-phase stationary coordinate system (abc) is converted to the two-phase stationary coordinate system (αβ) and the two-phase rotating coordinate system (dq) through coordinate transformation, realizing independent control of active current and reactive current; )and two-phase rotating coordinate system (dq) through coordinate transformation, realizing independent control of active current and reactive current;

[0119] Step 2-3) Design the operation control strategy of the charging and discharging machine model, according to the rectification state and inversion state of the charging and discharging machine model in grid-connected operation, determine the double-loop control strategy of the three-phase voltage PWM rectifier composed of voltage outer loop and current inner loop and the constant power control strategy of the bidirectional DC / DC converter, to realize the preset charging and discharging power target;

[0120] Step 2-4) Construct the control model of the bidirectional DC / DC converter, based on the electromagnetic transient simulation model library, select the switch model of the power electronic converter according to the demand; the control model of the bidirectional DC / DC converter can dynamically adjust the duty cycle of the power switch device according to the charging and discharging demand of the electric vehicle battery, so as to accurately control the voltage level output to the DC bus.

[0121] The application designs a charging and discharging machine model by combining a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter, so as to equivalently charge a pile by the charging and discharging machine model, and has the characteristics of high power factor, high working frequency, small size and small harmonic content, and the discharging energy of the charging and discharging machine model can be fully fed back to the power grid, thereby improving the energy utilization rate.

[0122] The three-phase voltage type PWM rectifier in the charging and discharging machine model is as shown in Figure 4 .

[0123] Step 2-1) The positive direction expression of the instantaneous voltage and the instantaneous current is:

[0124] ;

[0125] In the formula, , , is the grid voltage; is the reference voltage of the electric N;

[0126] The switching function of the rectifier bridge arm of the three-phase voltage type PWM rectifier is:

[0127] ;

[0128] In the formula, indicates the switching state of the kth phase of the three-phase voltage type PWM rectifier.

[0129] According to Kirchhoff's voltage law, taking the inductor current and the capacitor voltage as state variables, the following equation can be obtained:

[0130] ;

[0131] In the formula, , , is the AC input current; , , is the grid voltage; is the DC side load current; , , and are the voltage values of points A, B, C and O to the reference point N; is the DC bus voltage; is the AC side inductor; is the filter capacitor; is the loop equivalent resistance; is the DC side load equivalent resistance; is the DC side load equivalent voltage.

[0132] According to the three-phase balance principle of the main circuit, the following expression can be obtained:

[0133] ;

[0134] In the formula, is the voltage value from point O to reference point N; is the DC bus voltage; , , are the switching states of the a, b, and c phases of the three-phase voltage-type PWM rectifier, and when the value is 1, it indicates that the upper bridge arm of the phase is turned on and the lower bridge arm is turned off; when the value is 0, it indicates that the upper bridge arm of the phase is turned off and the lower bridge arm is turned on.

[0135] Step 2-2) The coordinate transformation is to simplify the decoupling control design, and the idea of motor vector control is used to map the three-phase stationary coordinate system abc to the two-phase stationary coordinate system and the two-phase rotating coordinate system dq.

[0136] The mathematical model expression of the three-phase voltage-type PWM rectifier in the three-phase stationary coordinate system (abc) is as follows:

[0137] ;

[0138] In the formula, , , is the AC input current; , , is the grid voltage; , , are the switching states of the a, b, and c phases of the three-phase voltage-type PWM rectifier; ; is the DC bus voltage; is the AC side inductance; is the filter capacitance; is the loop equivalent resistance; is the DC side load equivalent resistance; is the DC side load equivalent voltage.

[0139] The mathematical model of the main circuit in the two-phase stationary coordinate system is as follows:

[0140] ;

[0141] In the formula, , is the grid side voltage in the two-phase stationary coordinate system; , Two phases Current on the grid side in a stationary coordinate system; , Two phases Bridge wall opening / closing signals in a stationary coordinate system; This is the DC bus voltage; For AC side inductance; For filtering capacitors; The equivalent resistance of the circuit; The equivalent resistance of the DC-side load; This is the equivalent voltage of the DC-side load.

[0142] The mathematical model of the main circuit in the dq rotating coordinate system is as follows:

[0143] ;

[0144] In the formula, , The grid-side voltage is given in a two-phase dq rotating coordinate system. , Two phases Current on the grid side in a rotating coordinate system; , For the bridge wall turn-on and turn-off signals in the two-phase dq rotating coordinate system; It is the rotational angular velocity of the two-phase dq rotating coordinate system; This is the DC bus voltage; For AC side inductance; For filtering capacitors; The equivalent resistance of the circuit; The equivalent resistance of the DC-side load; This is the equivalent voltage of the DC-side load.

[0145] The operation control strategy of the three-phase voltage-source PWM rectifier described in steps 2-3) is as follows: Figure 3 As shown, when the charge / discharger model is in rectification mode, the three-phase voltage-type PWM rectifier adopts dual closed-loop control with voltage outer loop and current inner loop; when the charge / discharger model is in inverter mode, the bidirectional DC / DC converter adopts constant power (PQ) control strategy for grid connection, with grid frequency and voltage as the basis for regulation.

[0146] Steps 2-4) The control model of the bidirectional DC / DC converter is selected based on the requirements, choosing the switching model of the power electronic converter, for example, the attached... Figure 5 The figure shows the constant admittance model of a bidirectional DC / DC converter.

[0147] When the battery is charging, the bidirectional DC / DC converter VT1 is in the switching state, and VT2 is in the normally open state. The output voltage expression is:

[0148] ;

[0149] wherein, is the input voltage; is the output voltage; is the duty cycle; is the switching period; is the turn-on time.

[0150] When the battery is discharging, the bidirectional DC / DC converter VT1 is in a constant-off state, and VT2 is in a switching state, and the output voltage expression is:

[0151] ;

[0152] wherein, is the input voltage; is the output voltage; is the duty cycle; is the switching period; is the turn-off time.

[0153] By integrating the above electric vehicle battery model, power grid system model and charging and discharging machine model, a vehicle-to-grid interactive station level system capable of simulating a plurality of charging piles and other power equipment is finally formed.

[0154] The step 3) of establishing the large-scale vehicle-to-grid interactive station level model specifically comprises the following steps:

[0155] Step 3-1) establishing a charging and discharging machine model for a single electric vehicle charging pile, wherein: in the charging mode, the alternating current of the power grid is converted into direct current through the three-phase voltage type PWM rectifier and the PQ control strategy, and then the electric vehicle battery is charged through the bidirectional DC / DC converter; and in the discharging mode, when there is a power shortage in the power grid, the energy of the electric vehicle battery is boosted through the bidirectional DC / DC converter, and then the alternating current that meets the requirements of the power grid is converted by the three-phase voltage type PWM rectifier and fed back to the power grid;

[0156] Step 3-2) integrating the electromagnetic transient simulation model library and the charging and discharging machine model to construct a charging pile cluster cooperative response model, which is used to simulate the application scenarios of simultaneous grid charging or participating in vehicle-to-grid energy return of multiple electric vehicles, and each charging pile is connected in parallel through a common alternating current bus to access the same power grid access point;

[0157] Step 3-3) using the large-scale vehicle-to-grid interactive station level digital simulation system to evaluate the influence of the large-scale electric vehicle cluster on the transient stability level and dynamic operation characteristics of the power system after access, quantitatively analyze the contribution of the large-scale vehicle-to-grid interactive station level model to improving the vehicle-to-grid interaction capability, and verify the effectiveness of the large-scale vehicle-to-grid interactive station level model in supporting the orderly grid connection and coordinated control of large-scale electric vehicles; for example, Figure 6As shown, taking five charging piles accessing the power grid as an example, the scenario of multiple electric vehicles simultaneously accessing the grid for charging or participating in V2G interaction is simulated; each charging pile is connected in parallel to the same grid node through a common AC bus architecture, which truly restores the typical topology of centralized access of large-scale electric vehicle charging facilities.

[0158] To verify the effectiveness of the station-level modeling method of large-scale vehicle-grid interaction, the vehicle-grid interaction simulation system constructed in this embodiment including five charging piles is set to have a charging pile end voltage of 35 kV and a main grid voltage of 220 kV; the simulation system is configured to have a main grid voltage of 220 kV and a charging pile end voltage of 35 kV. Figure 7 and Figure 8 The simulation waveforms of active power and reactive power in the interaction process of the station-level charging station are shown, and the results effectively verify the feasibility and accuracy of the modeling method in simulating the large-scale vehicle-grid interaction scenario.

[0159] The application also includes a station-level simulation device for large-scale vehicle-grid interaction, which uses the method as described above, as shown in Figure 9 The station-level simulation device for large-scale vehicle-grid interaction includes:

[0160] Hardware part: considering the problems of complex development process and long development cycle in the traditional FPGA development process, the station-level simulation device for large-scale vehicle-grid interaction uses high-level synthesis (HLS) technology to design the core computing module of the large-scale vehicle-grid interaction station-level digital simulation system in the hardware part, which can improve the efficiency and flexibility of the simulation platform development; the hardware architecture of the station-level simulation device for large-scale vehicle-grid interaction is designed, and the core computing unit, input and output unit, and data interaction bus for real-time simulation are proposed; mainly including a multi-core parallel simulation solving unit containing a special simulation module, a network switch, an analog input module, an analog output module, a host computer, etc.

[0161] Software part: the software part of the station-level simulation device for large-scale vehicle-grid interaction is a large-scale vehicle-grid interaction station-level digital simulation system covering an electromagnetic transient simulation model library, an electric vehicle battery model, a power grid system model, and a charging and discharging machine model, which can perform electric vehicle station modeling, model editing, parameter configuration, fault setting, simulation recording, network decoupling, multi-rate simulation data interaction, etc. The large-scale vehicle-grid interaction station-level digital simulation system is developed independently using industrial-grade C++, adopts a Linux+RT embedded real-time operating system, optimizes its output precision, and reduces the jitter time; it innovatively integrates a hybrid modeling framework, a multi-time scale dynamic simulation algorithm, multi-model switching and automatic variable step size, sparse matrix solution, multi-core parallel computing, and power information mixing technology.

Claims

1. A method for modeling a station level of large-scale vehicle-network interaction, characterized in that Comprise: Step 1) constructing an electromagnetic transient simulation model library in a large-scale vehicle network interaction station-level simulation device, including a binary resistance model, an average value model and a constant admittance model; Step 2) constructing a charging and discharging machine model suitable for the charging and discharging process of an electric vehicle, the charging and discharging machine model being based on a three-phase voltage type PWM rectifier and a bidirectional DC / DC converter; Step 3) based on the electromagnetic transient simulation model library and the charging and discharging machine model, establishing a large-scale vehicle network interaction station-level digital simulation system, constructing a large-scale vehicle network interaction station-level model, using a common AC bus architecture to connect all charging piles in parallel to a power grid node, and realizing simulation of a dynamic interaction process in a large-scale electric vehicle grid-connected scenario.

2. The method of claim 1, wherein the method further comprises: The step of constructing the electromagnetic transient simulation model library specifically comprises: First, based on the topology structure of the power electronic converter, a switching modeling method is used to respectively establish a binary resistance model for fast screening of system-level stability and an average value model for dynamic characteristic analysis of the control loop; Then, the switching model is discretized by using the backward Euler method, and a constant admittance model is constructed to replace the computationally intensive detailed switching model; the constant admittance model establishes equivalent admittance expressions of the switching devices in the on and off states by introducing a historical current source term, thereby representing the steady-state and transient external characteristics of the converter; Finally, the binary resistance model, the average value model and the constant admittance model are integrated to form a multi-granularity electromagnetic transient simulation model library.

3. The method of claim 1, wherein the method further comprises: The construction process of the electromagnetic transient simulation model library comprises: Step 1-1) based on the topology structure and working principle of the power electronic converter, combining switching modeling, numerical discretization, linear interpolation and error compensation, a multi-granularity electromagnetic transient simulation model library including binary resistance models, average value models and constant admittance models is established, providing basic modeling elements for the establishment of electric vehicle battery models and power grid system models; Step 1-2) based on the electromagnetic transient simulation model library, constructing an electric vehicle battery model and a power grid system model.

4. The large-scale vehicle network interaction station-level modeling method according to claim 2 or 3, characterized by defining two extreme impedance states of the switching device according to the binary resistance model to simplify the representation: when the switch is on, it is equivalent to a small resistance; when the switch is off, it is equivalent to a large resistance; the equivalent conductance of the binary resistance model is switched accordingly, which is suitable for fast judgment of system-level stability, and the expression of the binary resistance model is: ； In the formula, is the equivalent conductance of the switch under the binary resistance model; is the minimum equivalent resistance when the switch is on; is the maximum equivalent resistance when the switch is off; According to the average value model, the pulsating voltage and current variables within the switching period are replaced by their periodic average values using the continuous time domain averaging method, and a circuit model equivalent to the external characteristics is formed through a controlled source as an interface; taking a voltage source type converter topology as an example, the average value model expression in the dq rotating coordinate is: ； wherein , , is the input current in dq rotating coordinates; , , is the input voltage in dq rotating coordinates; is the output voltage; , is the equivalent impedance of the voltage source inverter input; is the angle between the three-phase stationary coordinates and the dq rotating coordinates; M is the modulation ratio; is the rotating angular velocity of the two-phase dq rotating coordinate system; the average value model is suitable for the scenario analysis of a control loop bandwidth far lower than a switching frequency; According to the constant admittance model, small inductance and small capacitance are used as equivalent elements to replace the on and off state switches; the constant admittance model is based on the backward Euler discretization method to establish the parameter equation of the switching branch: ； wherein, Vbranch represents the branch voltage; Ibranch represents the branch current; t represents a time instant; and Ihistory represents the history current source in the on and off states, respectively; Yoff is the equivalent admittance when the switch is off; Rdamp is the damping resistance in series; dt represents the time step; A dynamic historical current compensation term is introduced to match the transient response of the ideal switch and the actual admittance model, and the expression of the historical current source after introducing the dynamic historical current compensation term is: ； In the formula, and respectively represent the historical current source in the on and off states after the dynamic historical current compensation term is introduced; represents the branch voltage; represents the branch current; , are respectively the voltage coefficient and the current coefficient in the on state; , are the voltage coefficient and the current coefficient in the off state; is the equivalent admittance when the switch is on; represents a certain moment; represents the time step.

5. The method of claim 3, wherein the method further comprises: According to the electric vehicle battery model, the non-linear external characteristics and dynamic response process of the electric vehicle battery are simulated by a programmable direct current power supply, and the accurate management and control of the charging and discharging power are realized through the controllable bidirectional DC / DC converter designed in the charging and discharging machine model; According to the power grid system model, all charging piles in the station are connected in the form of a "common AC bus", connected in parallel to the power grid node through a shared AC bus, which truly simulates the typical topology structure of the centralized access of large-scale electric vehicle charging facilities to the power grid, analyzes and evaluates the influence of large-scale load on the power grid, and supports the orderly grid connection of large-scale electric vehicles; According to the simulation requirements, the binary resistance model in the electromagnetic transient simulation model library is selected for system-level stability preliminary judgment, the average value model is used for control loop optimization, and the constant admittance model is used for accurate analysis of electromagnetic transient characteristics, to provide a balance between precision and efficiency for different application scenarios.

6. The method of claim 1, wherein the method further comprises: The specific process of constructing the charging and discharging machine model includes: Step 2-1) Establishing a mathematical model of a three-phase voltage type PWM rectifier, clearly defining the positive direction of the instantaneous voltage and the instantaneous current, and describing the on-off state of the rectifier bridge arm of the three-phase voltage type PWM rectifier based on the switching function, and deriving the dynamic relationship equation of the AC side voltage and current according to Kirchhoff's voltage law; Step 2-2) Coordinate transformation and decoupling control: the mathematical model of the three-phase voltage type PWM rectifier in the three-phase stationary coordinate system is converted to the two-phase stationary coordinate system and the two-phase rotating coordinate system through coordinate transformation, realizing independent control of active current and reactive current; Step 2-3) Designing the operation control strategy of the charging and discharging machine model, according to the rectification state and inversion state of the charging and discharging machine model in grid-connected operation, determining the double-loop control strategy of the three-phase voltage type PWM rectifier composed of voltage outer loop and current inner loop and the constant power control strategy of the bidirectional DC / DC converter, to realize the preset charging and discharging power target; Step 2-4) Constructing the control model of the bidirectional DC / DC converter, selecting the switching model of the power electronic converter according to the requirements based on the electromagnetic transient simulation model library; the control model of the bidirectional DC / DC converter can dynamically adjust the duty cycle of the power switch device according to the charging and discharging demand of the electric vehicle battery, so as to control the voltage level output to the DC bus.

7. The method of claim 6, wherein the method further comprises: The positive direction expression of the instantaneous voltage and the instantaneous current is: ； wherein , , is the grid voltage; is the voltage of the reference electrical N; The switching function of the rectifier bridge arm of the three-phase voltage type PWM rectifier is: ； In the formula, indicates the switching state of the kth phase of the three-phase voltage type PWM rectifier; According to Kirchhoff's voltage law, taking the inductor current and the capacitor voltage as state variables, the following equation can be obtained: ； wherein , , is the AC input current; , , is the grid voltage; is the DC side load current; , , and are the voltage values of points A, B, C and O to the reference point N; is the DC bus voltage; is the AC side inductance; is the filter capacitance; is the loop equivalent resistance; is the DC side load equivalent resistance; is the DC side load equivalent voltage; According to the three-phase balance principle of the main circuit, the following expression can be obtained: ； wherein is the voltage value from point O to reference point N; is the DC bus voltage; , , are the switching states of the three-phase voltage-type PWM rectifier a, b, c phases, when the value is 1, it indicates that the upper bridge arm of the phase is on, and the lower bridge arm is off; when the value is 0, it indicates that the upper bridge arm of the phase is off, and the lower bridge arm is on; The coordinate transformation in Step 2-2) is to simplify the decoupled control design, mapping the three-phase stationary coordinate system abc to the two-phase stationary coordinate system and the two-phase rotating coordinate system dq; The mathematical model expression of the three-phase voltage type PWM rectifier in the three-phase stationary coordinate system is: ； wherein , , is the AC input current; , , is the grid voltage; , , are the switching states of the three-phase voltage source PWM rectifier a, b, c phase respectively; ; is the DC bus voltage; is the AC side inductance; is the filter capacitance; is the loop equivalent resistance; is the DC side load equivalent resistance; is the DC side load equivalent voltage; The main circuit is in two phases The mathematical model in the stationary coordinate system is as follows: ； wherein, , is a two-phase grid-side voltage in the stationary coordinate system; , is a two-phase grid-side current in the stationary coordinate system; , is a two-phase bridge wall turn-on and turn-off signal in the stationary coordinate system; is a DC bus voltage; is an AC side inductance; is a filter capacitance; is a loop equivalent resistance; is a DC side load equivalent resistance; is a DC side load equivalent voltage; The mathematical model of the main circuit in the dq rotating coordinate system is: ； In the formula, , The grid-side voltage is given in a two-phase dq rotating coordinate system. , Two phases Current on the grid side in a rotating coordinate system; , For the bridge wall turn-on and turn-off signals in the two-phase dq rotating coordinate system; It is the rotational angular velocity of the two-phase dq rotating coordinate system; This is the DC bus voltage; For AC side inductance; For filtering capacitors; The equivalent resistance of the circuit; The equivalent resistance of the DC-side load; This is the equivalent voltage of the DC-side load.

8. The method of claim 6, wherein the method further comprises: Step 2-3) The operation control strategy of the three-phase voltage type PWM rectifier, when the charge-discharge machine model is in the rectification state, the three-phase voltage type PWM rectifier adopts the double closed loop control of the voltage outer ring and the current inner ring; when the charge-discharge machine model is in the inversion state, the bidirectional DC / DC converter adopts the constant power control strategy to be grid-connected, and the grid frequency and voltage are taken as the adjustment basis; Step 2-4) The control model of the bidirectional DC / DC converter selects the switching model of the power electronic converter according to the demand, when the battery is charging, the bidirectional DC / DC converter VT1 is in the switching state, VT2 is in the constant-off state, and the output voltage expression is: ； wherein is the input voltage; is the output voltage; is the duty cycle; is the switching period; is the turn-on time; When the battery is discharging, the bidirectional DC / DC converter VT1 is in the constant-off state, VT2 is in the switching state, and the output voltage expression is: ； wherein is the input voltage; is the output voltage; is the duty cycle; is the switching period; is the off time.

9. The method of claim 1, wherein the method further comprises: Step 3) The establishment of the large-scale vehicle-to-grid interactive station level model, specifically including: Step 3-1) The charge-discharge machine model is established for a single electric vehicle charging pile, wherein: in the charging mode, the alternating current of the power grid is converted into direct current through the three-phase voltage type PWM rectifier and the PQ control strategy, and then the battery of the electric vehicle is charged through the bidirectional DC / DC converter; and in the discharging mode, when there is a power shortage in the power grid, the energy of the battery of the electric vehicle is boosted through the bidirectional DC / DC converter, and then the alternating current that meets the requirements of the power grid is inverted by the three-phase voltage type PWM rectifier and fed back to the power grid; Step 3-2) The electromagnetic transient simulation model library and the charge-discharge machine model are integrated to construct a charging pile cluster cooperative response model, which is used to simulate the application scenarios of multiple electric vehicles simultaneously charging or participating in vehicle-to-grid energy return, and each charging pile is connected in parallel through a common alternating current bus to access the same power grid access point; Step 3-3) The large-scale vehicle-to-grid interactive station level digital simulation system is used to evaluate the influence of the large-scale electric vehicle cluster access on the transient stability level and dynamic operation characteristics of the power system, quantitatively analyze the contribution of the large-scale vehicle-to-grid interactive station level model to improving the vehicle-to-grid interaction ability, and verify the effectiveness of the large-scale vehicle-to-grid interactive station level model in supporting the orderly grid connection and coordinated control of large-scale electric vehicles.

10. The method of claim 1, wherein the method further comprises: The station level simulation device of the large-scale vehicle-to-grid interaction includes: The hardware part uses high-level synthesis technology to design the core computing module of the large-scale vehicle-to-grid interactive station level digital simulation system; the station level simulation device of the large-scale vehicle-to-grid interaction is designed in hardware architecture, and the core computing unit, input and output unit, and data interaction bus for real-time simulation are proposed; including a multi-core parallel simulation solving unit with a special simulation module, a network switch, an analog input module, an analog output module, and an upper computer. The software part is a large-scale vehicle-to-grid station-level digital simulation system covering an electromagnetic transient simulation model library, an electric vehicle battery model, a power grid system model and a charging and discharging machine model. The large-scale vehicle-to-grid station-level digital simulation system is developed by using an industrial C++, adopts a Linux+RT embedded real-time operating system, and integrates a hybrid modeling framework, a multi-time scale dynamic simulation algorithm, multi-model switching and automatic variable step length, sparse matrix solution, multi-core parallel computing and power information hybridization.

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