V2B charging system based on optical storage direct flexible mode

Abstract

The embodiment of the utility model provides a V2B charging system based on an optical storage direct flexible mode. The V2B charging system comprises a public power grid; the alternating current bus is connected with the public power grid through a first switch; the alternating current load is connected with the alternating current bus; the DC bus is connected with the AC bus through an AC / DC bidirectional rectifier; the energy storage device is connected with the direct current bus through an energy storage DC / DC bidirectional converter; the photovoltaic module is connected with the direct current bus through a photovoltaic DC / DC converter; the V2B charging pile is connected with the direct current bus; the direct current load is connected with the direct current bus through a step-down DC / DC converter; the insulation monitoring device is connected with the direct current bus; and the micro-grid controller is connected with the AC / DC bidirectional rectifier, the energy storage DC / DC bidirectional converter, the photovoltaic DC / DC converter, the V2B charging pile and the voltage reduction DC / DC converter.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy electric power, and in particular to a V2B charging system based on a photovoltaic storage direct-flexible mode. Background Art

[0002] V2G is the abbreviation of Vehicle-to-Grid. It is an electric vehicle charging station with a two-way energy flow function. It can not only supply power to and charge electric vehicles, but also obtain power from electric vehicles to achieve two-way energy transmission. The core concept of V2G charging stations is to treat electric vehicles that are parked as mobile energy storage devices, respond on the demand side of the power grid, provide emergency power supply and grid stability, and achieve interaction with the grid.

[0003] Distributed renewable energy generation is a beneficial supplement to traditional power generation, and has a significant role in promoting energy conservation and environmental protection. Therefore, it has received more and more attention. Small and medium-scale renewable energy generation has formed an industry, and medium and small grid-connected power sources have been widely used. At present, the photovoltaic storage direct-flexible system is an application model. When V2G integrates renewable energy, system control will become complicated, involving phase and frequency synchronization, resulting in reduced system stability, and may also cause certain interference to the power grid.

[0004] In the process of implementing the utility model, the applicant found that there are at least the following problems in the prior art:

[0005] Traditional V2G systems involve phase and frequency synchronization issues and are complex to control, which results in reduced system stability and interference with the power grid. Utility Model Content

[0006] The embodiment of the utility model provides a V2B charging system based on the photovoltaic storage direct-flexible mode, which solves the phase and frequency synchronization problems involved in the traditional V2G system, the complex control, the reduced system stability, and the interference with the power grid.

[0007] To achieve the above-mentioned objectives, on the one hand, an embodiment of the utility model provides a V2B charging system based on a photovoltaic-storage-direct-flexible mode, comprising: a public power grid; an AC bus connected to the public power grid through a first switch; an AC load connected to the AC bus; a DC bus connected to the AC bus through an AC / DC bidirectional rectifier; an energy storage device connected to the DC bus through an energy storage DC / DC bidirectional converter; a photovoltaic component connected to the DC bus through a photovoltaic DC / DC converter; a V2B charging pile connected to the DC bus; a DC load connected to the DC bus through a step-down DC / DC converter; an insulation monitoring device connected to the DC bus; and a microgrid controller connected to the AC / DC bidirectional rectifier, the energy storage DC / DC bidirectional converter, the photovoltaic DC / DC converter, the V2B charging pile, and the step-down DC / DC converter.

[0008] The above technical solution has the following beneficial effects: it adopts a vehicle-building interaction mode, overcoming the problem of traditional V2G mode that the interaction between vehicles and the power grid easily causes interference to the power grid; it adopts the photovoltaic storage direct-flexible mode, V2B can realize DC-DC transmission, making full use of the advantages of high reliability and high efficiency of the DC system, and effectively improving the interactive performance of V2B charging piles; it connects to photovoltaic new energy, energy storage devices and electric vehicles, and to a certain extent can realize the building to continue to supply power to the building load when the external AC power is lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 This is a schematic diagram of the architecture of a V2B charging system based on a solar-storage direct-flexible mode in one of the embodiments of the utility model;

[0011] Figure 2 This is a circuit schematic diagram of a push-pull phase-shifted full-bridge bidirectional DC / DC converter according to one embodiment of the utility model;

[0012] Figure 3 This is a circuit schematic diagram of an AC / DC bidirectional rectifier according to one embodiment of the utility model;

[0013] Figure 4 This is a circuit diagram of a step-down DC / DC converter according to one embodiment of the utility model;

[0014] Figure 5It is a schematic diagram of the architecture of a microgrid controller according to one embodiment of the present utility model.

[0015] The reference numerals are as follows: 10, public grid; K1, first switch; 11, AC bus; 12, AC load; 13, AC / DC bidirectional rectifier; 14, DC bus; 15, energy storage DC / DC bidirectional converter; 16, energy storage device; 17, photovoltaic DC / DC converter; 18, photovoltaic module; 19, V2B charging pile; 20, step-down DC / DC converter; 21, DC load; 22, insulation monitoring device; 23, microgrid controller; K2, second switch; K3, third switch; K4, fourth switch; K5, the The fifth switch; K6, the sixth switch; K7, the seventh switch; K8, the eighth switch; CL, the low-voltage side filter capacitor; Q1, the first power tube; Q2, the second power tube; LL, the low-voltage side inductor; T1, the high-frequency isolation transformer; Q3, the third power tube; Q4, the fourth power tube; Q5, the fifth power tube; Q6, the sixth power tube; Lr, the resonant inductor; Cr, the DC blocking capacitor; CH, the high-voltage side filter capacitor; Q7, the seventh power tube; Q8, the eighth power tube; Da1, the first rectifier diode of the first bridge arm; Da2, the second rectifier diode of the first bridge arm The first bridge arm has a first rectifier diode, a second rectifier diode, a third rectifier diode, a fourth rectifier diode, a fourth rectifier diode, a fifth ... ; Dc4, the fourth rectifier diode of the third bridge arm; Cd1, the first rectifier capacitor; Cd2, the second rectifier capacitor; Q13, the thirteenth power tube; L1, the first filter inductor; C1, the first filter capacitor; Dc, the first freewheeling diode; 231, the low-pass filter; 232, the operational amplifier; 233, the microgrid control processor; 234, the photoelectric isolation device; 235, the human-machine interface device; 236, the fault recording device; 237, the RS485 bus communication interface; 238, the CAN bus communication interface; 239, the Ethernet communication interface. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0017] On the one hand, if Figure 1 As shown, an embodiment of the present invention provides a V2B charging system based on a solar-storage direct-flexible mode, comprising:

[0018] A public power grid 10; an AC bus 11 connected to the public power grid 10 through a first switch K1; an AC load 12 connected to the AC bus 11; a DC bus 14 connected to the AC bus 11 through an AC / DC bidirectional rectifier 13; an energy storage device 16 connected to the DC bus 14 through an energy storage DC / DC bidirectional converter 15; a photovoltaic component 18 connected to the DC bus 14 through a photovoltaic DC / DC converter 17; a V2B charging pile 19 connected to the DC bus 14; a DC load 21 connected to the DC bus 14 through a step-down DC / DC converter 20; an insulation monitoring device 22 connected to the DC bus 14; and a microgrid controller 23 connected to the AC / DC bidirectional rectifier 13, the energy storage DC / DC bidirectional converter 15, the photovoltaic DC / DC converter 17, the V2B charging pile 19, and the step-down DC / DC converter 20.

[0019] In some embodiments, V2B is the abbreviation of Vehicle-to-Building, which is an electric vehicle charging pile with a bidirectional energy flow function. It can not only supply power to and charge electric vehicles, but also obtain electrical energy from electric vehicles to achieve bidirectional energy transmission. Unlike V2G, its energy interaction subject is the building photovoltaic storage direct and flexible system. The key configuration units of the system include: public power grid, photovoltaic components, energy storage batteries (energy storage devices), V2B charging piles, AC / DC converters (AC / DC bidirectional rectifiers), photovoltaic DC / DC converters, energy storage DC / DC converters (energy storage DC / DC bidirectional converters), DC electrical load DC / DC converters (step-down DC / DC converters), DC bus (DC750V) and microgrid controllers. Specifically: the public power grid, photovoltaic components, and energy storage batteries are each connected to the DC750V DC bus through AC / DC converters, photovoltaic DC / DC converters, and energy storage DC / DC converters for use by the DC V2B charging piles. At the same time, the charging piles can also feed back the electric energy in the car to the photovoltaic storage direct and flexible system for use by the DC loads. The V2B charging piles give priority to interacting with the electricity inside the building, reducing the need for interaction with the power grid, thereby reducing interference with the power grid. The system protection device uses insulation monitoring and DC circuit breakers. Configure the microgrid controller to issue voltage adjustment instructions when necessary to adjust the system operation status. Under normal operation, each converter in the system adopts a droop control mode to achieve power balance, set different voltage gradients, and set the highest priority voltage. During operation, the high voltage clamps the low voltage, and the high voltage converter discharges first; when mode adjustment is required (such as adjusting the system to prioritize energy storage power supply), the microgrid controller adjusts the output voltage of the converter through communication to achieve the purpose of adjusting the power supply priority of different equipment. A step-down DC / DC converter, such as a DC750V / DC220V conversion device, is set on the DC bus, and various DC devices can be plug-and-play.

[0020] In other embodiments, the microgrid controller is also connected to the first switch, and the microgrid controller can control the switching state of the first switch. When the electric vehicle supplies power to the building through the V2B charging pile, the first switch is disconnected, thereby disconnecting from the public grid, so that both the DC load and the AC load in the building can obtain electrical energy from the electric vehicle while avoiding interference with the public grid.

[0021] The embodiments of the present invention have the following technical effects: the mode of interaction between vehicles and buildings is adopted, which overcomes the problem of traditional V2G mode that the interaction between vehicles and power grids easily causes interference to the power grid; the photovoltaic storage direct-flexible mode is adopted, and V2B can realize DC-DC transmission, making full use of the advantages of high reliability and high efficiency of the DC system, and effectively improving the interactive performance of V2B charging piles; photovoltaic new energy, energy storage devices and electric vehicles are connected, which can, to a certain extent, realize that the building load continues to be powered when the external AC power is lost.

[0022] Furthermore, if Figure 1 As shown, the DC bus 14 is connected to the AC / DC bidirectional rectifier 13 via a second switch K2.

[0023] In some embodiments, a protection switch is provided to facilitate disconnection or connection between the DC bus 14 and the AC / DC bidirectional rectifier 13 .

[0024] Furthermore, if Figure 1 As shown, the energy storage DC / DC bidirectional converter 15 is connected to the DC bus 14 via a third switch K3.

[0025] In some embodiments, a protection switch is provided to facilitate disconnection or connection of the DC bus 14 with the energy storage system.

[0026] Furthermore, if Figure 1 As shown, the photovoltaic DC / DC converter 17 is connected to the DC bus 14 via a fourth switch K4.

[0027] In some embodiments, a protection switch is provided to facilitate disconnection or connection of the DC bus 14 with the photovoltaic system.

[0028] Furthermore, if Figure 1 As shown, the V2B charging pile 19 is connected to the DC bus 14 via a fifth switch K5.

[0029] In some embodiments, a protection switch is provided to facilitate disconnection or connection of the DC bus 14 with the charging pile.

[0030] Furthermore, the step-down DC / DC converter 20 is connected to the DC bus 14 via a sixth switch K6.

[0031] In some embodiments, a protection switch is provided to facilitate disconnection or connection of the DC bus 14 with the DC load.

[0032] Furthermore, if Figure 2 As shown, the V2B charging pile 19 includes: a push-pull phase-shifted full-bridge bidirectional DC / DC converter;

[0033] The push-pull phase-shifted full-bridge bidirectional DC / DC converter comprises: a low-voltage side filter capacitor CL, a first power tube Q1, a second power tube Q2, a low-voltage side inductor LL, a high-frequency isolation transformer T1, a third power tube Q3, a fourth power tube Q4, a fifth power tube Q5, a sixth power tube Q6, a resonant inductor Lr, a DC blocking capacitor Cr, and a high-voltage side filter capacitor CH;

[0034] A first power tube Q1 and a second power tube Q2 are respectively connected in series between the two ends of the low-voltage side winding of the high-frequency isolation transformer T1 and the low-voltage side reference ground;

[0035] A low-voltage side inductor LL is connected in series between the center tap of the low-voltage side winding of the high-frequency isolation transformer T1 and the low-voltage side voltage output terminal;

[0036] A low-voltage side filter capacitor CL is connected in parallel between the low-voltage side output terminal and the low-voltage side reference ground;

[0037] The third power tube Q3, the fourth power tube Q4, the fifth power tube Q5, and the sixth power tube Q6 form a full-bridge rectifier circuit;

[0038] The same direction end of the high-voltage side winding of the high-frequency isolation transformer T1 is connected to one end of the input end of the full-bridge rectifier circuit;

[0039] A resonant inductor Lr and a DC blocking capacitor Cr are connected in series between the reverse end of the high-voltage side winding of the high-frequency isolation transformer T1 and the other end of the input end of the full-bridge rectifier circuit;

[0040] One of the two output ends of the full-bridge rectifier circuit is connected to the high-voltage side reference ground, and a high-voltage side filter capacitor CH is connected in parallel between the other of the two output ends of the full-bridge rectifier circuit and the high-voltage side reference ground.

[0041] In some embodiments, Figure 2 As shown, the charging pile adopts a push-pull phase-shifted full-bridge bidirectional DC / DC converter, and an ARM processor can be used as the core device for realizing digital control, or other single-chip control chips can be used. UL is the low-voltage side voltage, CL is the low-voltage side filter capacitor, LL is the low-voltage side inductor, the first power tube Q1 and the second power tube Q2 use MOS tubes, Dp1 and Dp2 are parasitic diodes of the MOS tube, and Cp1 and Cp2 are parasitic capacitors of the MOS tube; UH is the high-voltage side voltage, T1 is a high-frequency isolation transformer, CH is a high-voltage side filter capacitor, the third power tube Q3, the fourth power tube Q4, the fifth power tube Q5 and the sixth power tube Q6 use MOS tubes, Dp3, Dp4, Dp5, Dp6 are parasitic diodes of the MOS tube, Cp3, Cp4, Cp5 and Cp6 are parasitic capacitors of the MOS tube, Lr is the resonant inductor, and Cr is the DC isolation capacitor.

[0042] Furthermore, if Figure 3 As shown, the AC / DC bidirectional rectifier 13 includes: a first bridge arm, a second bridge arm, a third bridge arm and a filter output circuit;

[0043] The first bridge arm, the second bridge arm, the third bridge arm and the filter output circuit are connected in parallel; wherein two ends of the filter output circuit are connected to the DC bus 14;

[0044] The first bridge arm includes: a seventh power tube Q7, an eighth power tube Q8, a first bridge arm first rectifier diode Da1, a first bridge arm second rectifier diode Da2, a first bridge arm third rectifier diode Da3, and a first bridge arm fourth rectifier diode Da4;

[0045] The negative end of the third rectifier diode Da3 of the first bridge arm is connected in series with the positive end of the second rectifier diode Da2 of the first bridge arm;

[0046] The first bridge arm first rectifier diode Da1, the seventh power tube Q7, the eighth power tube Q8 and the first bridge arm fourth rectifier diode Da4 are connected in series;

[0047] The negative end of the second rectifier diode Da2 of the first bridge arm is connected between the first rectifier diode Da1 of the first bridge arm and the seventh power tube Q7;

[0048] The forward end of the third rectifier diode Da3 of the first bridge arm is connected between the fourth rectifier diode Da4 of the first bridge arm and the eighth power tube Q8;

[0049] Phase A of the AC bus 11 is connected between the third rectifier diode Da3 of the first bridge arm and the second rectifier diode Da2 of the first bridge arm;

[0050] The second bridge arm includes: a ninth power tube Q9, a tenth power tube Q10, a second bridge arm first rectifier diode Db1, a second bridge arm second rectifier diode Db2, a second bridge arm third rectifier diode Db3, and a second bridge arm fourth rectifier diode Db4;

[0051] The negative end of the third rectifier diode Db3 of the second bridge arm is connected in series with the positive end of the second rectifier diode Db2 of the second bridge arm;

[0052] The first rectifier diode Db1 of the second bridge arm, the ninth power tube Q9, the tenth power tube Q10 and the fourth rectifier diode Db4 of the second bridge arm are connected in series;

[0053] The negative end of the second rectifier diode Db2 of the second bridge arm is connected between the first rectifier diode Db1 of the second bridge arm and the ninth power tube Q9;

[0054] The forward end of the third rectifier diode Db3 of the second bridge arm is connected between the fourth rectifier diode Db4 of the second bridge arm and the tenth power tube Q10;

[0055] The B phase of the AC bus 11 is connected between the third rectifier diode Db3 of the second bridge arm and the second rectifier diode Db2 of the second bridge arm;

[0056] The third bridge arm includes: an eleventh power tube Q11, a twelfth power tube Q12, a first rectifier diode Dc1 of the third bridge arm, a second rectifier diode Dc2 of the third bridge arm, a third rectifier diode Dc3 of the third bridge arm, and a fourth rectifier diode Dc4 of the third bridge arm.

[0057] The negative end of the third rectifier diode Dc3 of the third bridge arm is connected in series with the positive end of the second rectifier diode Dc2 of the third bridge arm;

[0058] The first rectifier diode Dc1 of the third bridge arm, the eleventh power tube Q11, the twelfth power tube Q12 and the fourth rectifier diode Dc4 of the third bridge arm are connected in series;

[0059] The negative end of the second rectifier diode Db2 of the third bridge arm is connected between the first rectifier diode Dc1 of the third bridge arm and the eleventh power tube Q11;

[0060] The forward end of the third rectifier diode Dc3 of the third bridge arm is connected between the fourth rectifier diode Dc4 of the third bridge arm and the twelfth power tube Q12;

[0061] The C phase of the AC bus 11 is connected between the third rectifier diode Dc3 of the third bridge arm and the second rectifier diode Dc2 of the third bridge arm;

[0062] The middle of the seventh power tube Q7 and the eighth power tube Q8, the middle of the ninth power tube Q9 and the tenth power tube Q10, and the middle of the eleventh power tube Q11 and the twelfth power tube Q12 are short-circuited to each other;

[0063] The filter output circuit includes: a first rectifier capacitor Cd1 and a second rectifier capacitor Cd2; the first rectifier capacitor Cd1 and the second rectifier capacitor Cd2 are connected in series.

[0064] In some embodiments, by Figure 3In the power frequency isolation type AC / DC rectifier topology shown, the DC side and the AC side are connected through the AC / DC rectifier converter, which can realize the rectification and power supply from the AC side to the DC side. The rectification adopts the Vienna rectifier converter. The rectifier circuit structure is simple and the number of switch tubes is small. Under the same output voltage, the voltage stress of the switch tube can be effectively reduced. At the same time, the input of the rectifier adopts the isolation transformer to realize the effective electrical isolation of the DC system and the AC system.

[0065] Furthermore, if Figure 4 As shown, the step-down DC / DC converter 20 includes: a thirteenth power tube Q13, a first filter inductor L1, a first filter capacitor C1 and a first freewheeling diode Dc;

[0066] The thirteenth power tube Q13, the first filter inductor L1, and the first filter capacitor C1 are sequentially connected in series between the high-voltage side positive input terminal of the step-down DC / DC converter 20 and the reference ground of the step-down DC / DC converter 20;

[0067] The negative end of the first freewheeling diode Dc is connected between the thirteenth power tube Q13 and the first filter inductor L1;

[0068] The forward end of the first freewheeling diode Dc is connected to the reference ground of the step-down DC / DC converter 20;

[0069] Two ends of the first filter capacitor C1 are connected to the low-voltage output end of the step-down DC / DC converter 20 .

[0070] In some embodiments, the step-down DC / DC converter adopts a BUCK step-down topology, and adjusts the output voltage by controlling the duty cycle of the switching device, and can output DC375V or DC220V to power common DC loads.

[0071] Furthermore, if Figure 5 As shown, the microgrid controller 23 includes: a low-pass filter 231, an operational amplifier 232, a microgrid control processor 233, a photoelectric isolation device 234, a human-machine interface device 235, a fault recording device 236, and a communication interface;

[0072] The microgrid control processor 233 is connected to the human-machine interface device 235 to receive instructions;

[0073] The photoelectric isolation device 234 is connected to the first switch K1;

[0074] The microgrid control processor 233 is connected to the photoelectric isolation device 234 to sample and / or control the switch state of the first switch K1;

[0075] The low-pass filter 231 is connected to the AC / DC bidirectional rectifier, the energy storage DC / DC bidirectional converter, the photovoltaic DC / DC converter, the buck DC / DC converter and the V2B charging pile to sample the voltage and current in the AC / DC bidirectional rectifier, the energy storage DC / DC bidirectional converter, the photovoltaic DC / DC converter, the buck DC / DC converter and the V2B charging pile;

[0076] The operational amplifier 232 is connected to the low-pass filter 231 to amplify the sampled voltage and current;

[0077] The microgrid control processor 233 is connected to the operational amplifier 232 to control the voltage and current of the AC / DC bidirectional rectifier, the energy storage DC / DC bidirectional converter, the photovoltaic DC / DC converter, the step-down DC / DC converter and the V2B charging pile according to the received instructions and the sampled and amplified voltage and current, and to control the on / off state of the first switch K1;

[0078] The microgrid control processor 233 is connected to the fault recording device 236 to record the runtime faults;

[0079] The microgrid control processor 233 is connected to the communication interface to communicate with the remote server;

[0080] The communication interface includes an RS485 bus communication interface 237 , a CAN bus communication interface 238 and an Ethernet communication interface 239 .

[0081] In some embodiments, Figure 5 As shown in the figure, the schematic diagram of the microgrid controller obtains the status of each converter in the system through the communication interface, and retains the voltage and current sampling ports and the switch input and output ports. The instruction processing is realized through DSP, single-chip microcomputer, etc. The microgrid controller obtains the operating data of each converter in the system through sampling or communication, and sets the voltage value according to the instructions of the human-machine interface to change the operation strategy of the system. Configure the microgrid controller to issue voltage adjustment instructions when necessary to adjust the system operation status. Under normal operation, each converter in the system adopts the droop control mode to achieve power balance, set different voltage gradients, and set the highest priority voltage to the highest. When running, the high voltage clamps the low voltage, and the high voltage converter discharges first; when the mode adjustment is required (such as adjusting the system to prioritize energy storage power supply), the microgrid controller adjusts the output voltage of the converter through communication to achieve the purpose of adjusting the power supply priority of different equipment.

[0082] In other embodiments, Figure 1As shown, the DC bus 14 is connected to the AC / DC bidirectional rectifier 13 through the second switch K2. The energy storage DC / DC bidirectional converter 15 is connected to the DC bus 14 through the third switch K3. The photovoltaic DC / DC converter 17 is connected to the DC bus 14 through the fourth switch K4. The V2B charging pile 19 is connected to the DC bus 14 through the fifth switch K5. The step-down DC / DC converter 20 is connected to the DC bus 14 through the sixth switch K6. The insulation monitoring device is connected to the DC bus 14 through the seventh switch K7. The AC load is connected to the AC bus 11 through the eighth switch K8. The photoelectric isolation device 234 is also connected to the first switch K2, the first switch K3, the first switch K4, the first switch K5, the first switch K6, the first switch K7, and the first switch K8 to sample the state of each switch.

[0083] Furthermore, the insulation monitoring device is connected to the DC bus 14 via a seventh switch K7.

[0084] In some embodiments, a protection switch is provided to facilitate disconnection or connection of the DC bus 14 with the insulation monitoring device.

[0085] Furthermore, the AC load is connected to the AC bus 11 via an eighth switch K8.

[0086] In some embodiments, a protective switch is provided to facilitate disconnection or connection between the AC bus 11 and the AC load.

[0087] Furthermore, the public power grid is AC10KV / 380V.

[0088] Furthermore, the voltage level of the DC bus is DC750V.

[0089] The DC750V voltage level is adopted. Compared with the AC380V voltage level, the power transmission distance is longer and the spatial configuration of the system is more flexible.

[0090] Furthermore, the step-down DC / DC converter is a DC750V / DC220V converter.

[0091] A DC750V / DC220V conversion device is installed on the DC bus, and various DC devices can be plug-and-play.

[0092] The above technical scheme of the embodiment of the utility model is described in detail below in conjunction with specific application examples. For technical details not introduced during the implementation process, please refer to the relevant description in the previous text.

[0093] V2B is the abbreviation of Vehicle-to-Building. It is an electric vehicle charging pile with a bidirectional energy flow function. It can not only supply power to and charge electric vehicles, but also obtain electric energy from electric vehicles to achieve bidirectional energy transmission. Unlike V2G, its energy interaction subject is the building photovoltaic storage direct and flexible system. The key configuration units of the system include: public power grid, photovoltaic components, energy storage batteries, V2B charging piles, AC / DC converters, photovoltaic DC / DC converters, energy storage DC / DC converters, DC electrical load DC / DC converters and DC750V DC bus. Specifically: the public power grid, photovoltaic components, and energy storage batteries are each connected to the DC750V DC bus through AC / DC converters, photovoltaic DC / DC converters, and energy storage DC / DC converters for use by the DC V2B charging piles. At the same time, the charging piles can also feed back the electric energy in the car to the photovoltaic storage direct and flexible system for use by the DC load. The V2B charging piles interact with the internal electricity of the building first, reducing the need for interaction with the power grid, thereby reducing interference to the power grid. The system protection device uses insulation monitoring and DC circuit breakers.

[0094] Figure 1 This is a schematic diagram of a V2B charging system based on the photovoltaic storage direct-flexible mode. The key configuration units of the system include: public power grid, photovoltaic components, energy storage batteries, V2B charging piles, AC / DC converters, photovoltaic DC / DC converters, energy storage DC / DC converters, step-down DC / DC converters, DC electrical load DC / DC converters and DC750V DC bus. Specifically: the public power grid, photovoltaic components, energy storage batteries, and DC loads are connected to the DC750V DC bus through AC / DC converters, photovoltaic DC / DC converters, energy storage DC / DC converters, and energy storage DC / DC converters, and the DC V2B charging piles are directly connected to the DC750V DC bus. The V2B charging piles interact with the internal electricity of the building first, reducing the need for interaction with the power grid, thereby reducing interference with the power grid. The system protection device uses insulation monitoring and DC circuit breakers. Configure a microgrid controller to issue voltage adjustment instructions when necessary to adjust the system operation status.

[0095] Under normal operation, each converter in the system uses a droop control mode to achieve power balance, set different voltage gradients, and set the highest priority voltage. When the high voltage clamps the low voltage during operation, the high voltage converter discharges first. When the mode needs to be adjusted (such as adjusting the system to prioritize energy storage power supply), the microgrid controller adjusts the output voltage of the converter through communication to achieve the purpose of adjusting the power supply priority of different equipment. A DC750V / DC220V conversion device is set on the DC bus, and various DC devices can be plug-and-play.

[0096] Figure 2The topological structure diagram of the charging pile. The charging pile adopts a push-pull phase-shifted full-bridge bidirectional DC / DC converter. The device can use an ARM processor as the core device for digital control, or other single-chip control chips. UL is the low-voltage side voltage, CL is the low-voltage side filter capacitor, LL is the low-voltage side inductor, power tubes Q1 and Q2 use MOS tubes, Dp1 and Dp2 are parasitic diodes of MOS tubes, and Cp1 and Cp2 are parasitic capacitors of MOS tubes; UH is the high-voltage side voltage, T1 is a high-frequency isolation transformer, CH is a high-voltage side filter capacitor, power tubes Q3, Q4, Q5 and Q6 use MOS tubes, Dp3, Dp4, Dp5, Dp6 are parasitic diodes of MOS tubes, Cp3, Cp4, Cp5 and Cp6 are parasitic capacitors of MOS tubes, Lr is the resonant inductor, and Cr is the DC isolation capacitor.

[0097] Figure 3 This is the topology diagram of the power frequency isolated AC / DC rectifier. The DC side and the AC side are connected through an AC / DC rectifier converter, which can realize the rectification and power supply from the AC side to the DC side. The rectification adopts the Vienna rectifier converter. The rectifier circuit structure is simple and the number of switch tubes is small. Under the same output voltage, it can effectively reduce the voltage stress of the switch tube. At the same time, the input of the rectifier adopts an isolation transformer to realize the effective electrical isolation of the DC system and the AC system.

[0098] Figure 4 The step-down DC / DC converter adopts the BUCK step-down topology and adjusts the output voltage by controlling the duty cycle of the switching device. It can output DC375V or DC220V to power common DC loads.

[0099] Figure 5 It is a schematic diagram of the microgrid controller. The status of each converter in the system is obtained through the communication interface, and the voltage and current sampling ports and the switch input and output ports are retained. The instruction processing is realized through DSP, single-chip microcomputer, etc. The microgrid controller obtains the operating data of each converter in the system through sampling or communication, and sets the voltage value according to the instructions of the human-machine interface to change the system's operating strategy.

[0100] The embodiments of the utility model have the following technical effects: the mode of vehicle-building interaction is adopted to overcome the problem of traditional V2G mode that the interaction between vehicles and the power grid easily causes interference to the power grid; the photovoltaic storage direct-flexible mode is adopted, and V2B can realize DC-DC transmission, making full use of the advantages of high reliability and high efficiency of the DC system, and effectively improving the interactive performance of V2B charging piles; photovoltaic new energy, energy storage devices and electric vehicles are connected, and to a certain extent, the building can continue to supply power to the building load when the external AC power is lost; the DC750V voltage level is adopted, compared with the AC380V voltage level, the power transmission distance is farther, and the spatial configuration of the system is more flexible. A DC750V / DC220V conversion device is set on the DC bus, and various DC devices can be plug-and-play.

[0101] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0102] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than those clearly stated in each claim. On the contrary, as reflected in the attached claims, the utility model is in a state with less than all the features of the disclosed individual embodiments. Therefore, the attached claims are hereby expressly incorporated into the detailed description, with each claim acting alone as a separate preferred embodiment of the utility model.

[0103] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in the present application.

[0104] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including". In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0105] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only the specific implementation method of the utility model and is not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A V2B charging system based on a solar-storage direct-flexible mode, characterized in that: include: A public power grid (10); an AC bus (11) connected to the public power grid (10) via a first switch (K1); an AC load (12) connected to the AC bus (11); a DC bus (14) connected to the AC bus (11) via an AC / DC bidirectional rectifier (13); an energy storage device (16) connected to the DC bus (14) via an energy storage DC / DC bidirectional converter (15); and a photovoltaic module (17) connected to the DC bus (14). 8); a V2B charging pile (19) connected to the DC bus (14); a DC load (21) connected to the DC bus (14) via a step-down DC / DC converter (20); an insulation monitoring device (22) connected to the DC bus (14); and a microgrid controller (23) connected to the AC / DC bidirectional rectifier (13), the energy storage DC / DC bidirectional converter (15), the photovoltaic DC / DC converter (17), the V2B charging pile (19), and the step-down DC / DC converter (20).

2. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The DC bus (14) is connected to the AC / DC bidirectional rectifier (13) via a second switch (K2).

3. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The energy storage DC / DC bidirectional converter (15) is connected to the DC bus (14) via a third switch (K3).

4. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The photovoltaic DC / DC converter (17) is connected to the DC bus (14) via a fourth switch (K4).

5. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The V2B charging pile (19) is connected to the DC bus (14) via a fifth switch (K5).

6. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The step-down DC / DC converter (20) is connected to the DC bus (14) via a sixth switch (K6).

7. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The V2B charging pile (19) comprises: a push-pull phase-shifted full-bridge bidirectional DC / DC converter; The push-pull phase-shifted full-bridge bidirectional DC / DC converter comprises: a low-voltage side filter capacitor (CL), a first power tube (Q1), a second power tube (Q2), a low-voltage side inductor (LL), a high-frequency isolation transformer (T1), a third power tube (Q3), a fourth power tube (Q4), a fifth power tube (Q5), a sixth power tube (Q6), a resonant inductor (Lr), a DC blocking capacitor (Cr), and a high-voltage side filter capacitor (CH); A first power tube (Q1) and a second power tube (Q2) are respectively connected in series between two ends of the low-voltage side winding of the high-frequency isolation transformer (T1) and the low-voltage side reference ground; A low-voltage side inductor (LL) is connected in series between the center tap of the low-voltage side winding of the high-frequency isolation transformer (T1) and the low-voltage side voltage output terminal; A low-voltage side filter capacitor (CL) is connected in parallel between the low-voltage side output terminal and the low-voltage side reference ground; The third power tube (Q3), the fourth power tube (Q4), the fifth power tube (Q5) and the sixth power tube (Q6) form a full-bridge rectifier circuit; The same direction end of the high-voltage side winding of the high-frequency isolation transformer (T1) is connected to one end of the input end of the full-bridge rectifier circuit; A resonant inductor (Lr) and a DC blocking capacitor (Cr) are connected in series between the reverse end of the high-voltage side winding of the high-frequency isolation transformer (T1) and the other end of the input end of the full-bridge rectifier circuit; One of the two output ends of the full-bridge rectifier circuit is connected to the high-voltage side reference ground, and a high-voltage side filter capacitor (CH) is connected in parallel between the other end of the two output ends of the full-bridge rectifier circuit and the high-voltage side reference ground.

8. The V2B charging system based on the solar-storage direct-flexible mode as claimed in claim 1, characterized in that: The AC / DC bidirectional rectifier (13) comprises: a first bridge arm, a second bridge arm, a third bridge arm and a filter output circuit; The first bridge arm, the second bridge arm, the third bridge arm and the filter output circuit are connected in parallel; wherein two ends of the filter output circuit are connected to the DC bus (14); The first bridge arm comprises: a seventh power tube (Q7), an eighth power tube (Q8), a first bridge arm first rectifier diode (Da1), a first bridge arm second rectifier diode (Da2), a first bridge arm third rectifier diode (Da3), and a first bridge arm fourth rectifier diode (Da4); The negative end of the third rectifier diode (Da3) of the first bridge arm is connected in series with the positive end of the second rectifier diode (Da2) of the first bridge arm; The first bridge arm first rectifier diode (Da1), the seventh power tube (Q7), the eighth power tube (Q8) and the first bridge arm fourth rectifier diode (Da4) are connected in series; The negative end of the second rectifier diode (Da2) of the first bridge arm is connected between the first rectifier diode (Da1) of the first bridge arm and the seventh power tube (Q7); The forward end of the third rectifier diode (Da3) of the first bridge arm is connected between the fourth rectifier diode (Da4) of the first bridge arm and the eighth power tube (Q8); Phase A of the AC busbar (11) is connected between the third rectifier diode (Da3) of the first bridge arm and the second rectifier diode (Da2) of the first bridge arm.

9. The V2B charging system based on the solar-storage direct-flexible mode of claim 1 is characterized in that: The step-down DC / DC converter (20) comprises: a thirteenth power tube (Q13), a first filter inductor (L1), a first filter capacitor (C1) and a first freewheeling diode (Dc); The thirteenth power tube (Q13), the first filter inductor (L1), and the first filter capacitor (C1) are sequentially connected in series between the high-voltage side positive input terminal of the step-down DC / DC converter (20) and the reference ground of the step-down DC / DC converter (20); The negative end of the first freewheeling diode (Dc) is connected between the thirteenth power tube (Q13) and the first filtering inductor (L1); A forward end of the first freewheeling diode (Dc) is connected to a reference ground of the step-down DC / DC converter (20); Both ends of the first filter capacitor (C1) are connected to the low-voltage side output end of the step-down DC / DC converter (20).

10. The V2B charging system based on the solar-storage direct-flexible mode of claim 1 is characterized in that: The microgrid controller (23) comprises: a low-pass filter (231), an operational amplifier (232), a microgrid control processor (233), a photoelectric isolation device (234), a human-machine interface device (235), a fault recording device (236), and a communication interface; The microgrid control processor (233) is connected to the human-machine interface device (235); The photoelectric isolation device (234) is connected to the first switch (K1); The microgrid control processor (233) is connected to the photoelectric isolation device (234); The low-pass filter (231) is connected to the AC / DC bidirectional rectifier, the energy storage DC / DC bidirectional converter, the photovoltaic DC / DC converter, the step-down DC / DC converter and the V2B charging pile; The operational amplifier (232) is connected to the low-pass filter (231); The microgrid control processor (233) is connected to the operational amplifier (232); The microgrid control processor (233) is connected to the fault recording device (236); The microgrid control processor (233) is connected to the communication interface; The communication interface comprises an RS485 bus communication interface (237), a CAN bus communication interface (238) and an Ethernet communication interface (239).

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