Power self-adaptive charger based on cogeneration and topology reconstruction

Abstract

The invention relates to the technical field of new energy charging, and discloses a power self-adaptive charger based on cogeneration and topology reconstruction, the output end of a DC / DC power module and the output end of a TEG are connected in parallel to a direct current bus, so that waste heat generated by the DC / DC power module is directly converted into direct current electric energy of the direct current bus, and the direct current electric energy of the direct current bus is converted into direct current electric energy. Waste heat in the high-power charging process can be effectively recycled, heat dissipation energy consumption can be further reduced, the central controller can control the DCA to be switched to the corresponding power buffer mode or reactive compensation mode in a capacitor topology reconstruction mode according to the vehicle battery demand power in combination with the real-time power grid voltage and the real-time power factor, and the power consumption can be reduced. Compared with the prior art, the self-adaptive adjustment of the overall power can be realized through the switching of the working modes of the charger, and a reactive compensation cabinet or a peak energy storage cabinet does not need to be additionally arranged, so that the diversified scene requirements of the charger can be met, the energy efficiency of the charger can be improved, and the application cost can be greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy charging, and in particular to a power adaptive charger based on combined heat and power and topology reconstruction. BACKGROUND

[0002] With the rapid increase of the penetration rate of electric vehicles, the demand for high-power direct current fast charging has also increased rapidly, and the power level of the charger has gradually moved from hundreds of kilowatts to megawatts. At present, considering that a large amount of waste heat will be generated during the operation of the power module, the traditional technology mainly relies on forced air cooling or water cooling system to dissipate heat of the power module, but the energy consumption is high, the structure is complex, and the heat utilization rate is not high, and when facing short-time fluctuations or peak demand of the power grid, the charger can only operate at a reduced capacity, which cannot meet the different scene application requirements of the charger. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art. To this end, the present application provides a power adaptive charger based on combined heat and power and topology reconstruction, which can effectively recover and utilize waste heat during high-power charging, and meet the diversified scene requirements of the charger.

[0004] The present application provides a power adaptive charger based on combined heat and power and topology reconstruction, the power adaptive charger is configured with a direct current bus and a charging gun, and an output end of the direct current bus is connected to the charging gun; the power adaptive charger comprises:

[0005] a combined heat and power layer, comprising a DC / DC power module, a heat sink integrated on the DC / DC power module, and a thermoelectric generator arranged on one side of the heat sink, an output end of the DC / DC power module and an output end of the thermoelectric generator being connected in parallel to the direct current bus;

[0006] a dynamic capacitor array connected to the direct current bus and capable of realizing capacitor topology reconstruction;

[0007] a central controller connected to the dynamic capacitor array and used for controlling the dynamic capacitor array to switch to a power buffer mode or a reactive power compensation mode according to the acquired vehicle battery demand power in combination with real-time power grid voltage and real-time power factor;

[0008] wherein, in the power buffer mode, the dynamic capacitor array discharges to reduce the bus voltage of the direct current bus; and in the reactive power compensation mode, the dynamic capacitor array outputs reactive power to increase the bus voltage of the direct current bus.

[0009] Optionally, in an embodiment of the present application, the dynamic capacitor array comprises a high-speed switching matrix and a super capacitor group, the high-speed switching matrix is connected to the central controller and the super capacitor group respectively, and the high-speed switching matrix is configured to adjust a real-time topology state of the super capacitor group according to a control instruction from the central controller.

[0010] Optionally, in an embodiment of the present application, the super capacitor group comprises a plurality of super capacitors.

[0011] In a case where the central controller controls the dynamic capacitor array to switch to the power buffer mode, the high-speed switching matrix is specifically configured to switch a plurality of the super capacitors to be connected in parallel.

[0012] Or,

[0013] In a case where the central controller controls the dynamic capacitor array to switch to the reactive compensation mode, the high-speed switching matrix is specifically configured to switch a plurality of the super capacitors to be connected in series with an H-bridge chain.

[0014] Optionally, in an embodiment of the present application, the central controller is specifically configured to:

[0015] In a case where it is determined that the obtained vehicle battery demand power is less than a preset maximum limit output power of the power grid, the central controller controls the dynamic capacitor array to switch to the power buffer mode.

[0016] Optionally, in an embodiment of the present application, the central controller is specifically configured to:

[0017] In a case where it is detected that a decrease amplitude of the real-time power grid voltage reaches a preset voltage decrease amplitude or the real-time power factor is less than a preset minimum power factor, the central controller controls the dynamic capacitor array to switch to the reactive compensation mode.

[0018] Optionally, in an embodiment of the present application, in a case where the central controller controls the dynamic capacitor array to switch to the reactive compensation mode, the thermoelectric generator is configured to continuously generate power to supplement energy consumption of the dynamic capacitor array, so that a real-time state of charge of the dynamic capacitor array is maintained at a preset interval level.

[0019] Optionally, in an embodiment of the present application, further comprising an anti-reverse diode, and an output end of the thermoelectric generator is connected to the DC bus through the anti-reverse diode.

[0020] Optionally, in an embodiment of the present application, an EMI filter unit and a PFC topology are further included, an input end of the EMI filter unit is connected to a mains input voltage, and an output end of the EMI filter unit is connected to the DC / DC power module through the PFC topology.

[0021] Optionally, in an embodiment of the present application, the central controller triggers the high-speed switching matrix through an optical fiber.

[0022] The power adaptive charger based on combined heat and power and topology reconstruction provided by the present application realizes heat dissipation transmission of the heat sink to the DC / DC power module by configuring the heat sink integrated on the DC / DC power module and the thermoelectric generator arranged on the surface of the heat sink, especially, the output end of the DC / DC power module and the output end of the thermoelectric generator are connected in parallel to the DC bus, so that the waste heat generated by the DC / DC power module is directly converted into DC power of the DC bus, which can effectively recycle the waste heat in the high-power charging process, is conducive to further reducing the heat dissipation energy consumption, and the central controller can control the dynamic capacitor array to switch to the corresponding power buffer mode or the reactive power compensation mode through the capacitor topology reconstruction according to the vehicle battery demand power combined with the real-time grid voltage and the real-time power factor, compared with the related prior art, the power adaptive adjustment of the whole machine can be realized through the working mode switching of the charger, and the reactive power compensation cabinet or the peak energy storage cabinet does not need to be additionally increased, which not only can meet the diversified scene demand of the charger and improve the energy efficiency of the charger, but also can greatly reduce the application cost. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the power adaptive charger based on combined heat and power and topology reconstruction provided by an embodiment of the present application;

[0024] Figure 2 is a structural schematic diagram of the combined heat and power layer provided by an embodiment of the present application;

[0025] Figure 3 is a structural schematic diagram of the dynamic capacitor array provided by an embodiment of the present application;

[0026] Figure 4 is a working principle schematic diagram of the power adaptive charger based on combined heat and power and topology reconstruction provided by an embodiment of the present application;

[0027] Figure 5 is a topology principle diagram of the dynamic capacitor array switched to the power buffer mode provided by an embodiment of the present application;

[0028] Figure 6 is a topology principle diagram of the dynamic capacitor array switched to the reactive power compensation mode provided by an embodiment of the present application. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Figure 1 This is a schematic diagram of a power adaptive charger based on combined heat and power and topology reconfiguration, provided as an embodiment of the present invention. Figure 1 As shown, this power adaptive charger is equipped with a DC bus and a charging gun. The output end of the DC bus is connected to the charging gun. Specifically, the power adaptive charger may include, but is not limited to:

[0031] The combined heat and power (CHP) layer includes a DC / DC power module, a heat sink integrated on the DC / DC power module, and a thermoelectric generator (hereinafter referred to as TEG) located on one side of the heat sink. The output terminals of the DC / DC power module and the TEG are connected in parallel to the DC bus.

[0032] The dynamic capacitor array (hereinafter referred to as DCA for ease of description) is connected to the DC bus and can realize capacitor topology reconfiguration.

[0033] The central controller, connected to the DCA, is used to control the DCA to switch to power buffer mode or reactive power compensation mode based on the obtained vehicle battery power demand combined with real-time grid voltage and real-time power factor.

[0034] In the power buffer mode, DCA discharges to reduce the bus voltage of the DC bus, aiming to provide peak power support for a short time (≤30s) to make up for grid gaps and avoid charging speed reduction. In the reactive power compensation mode, DCA outputs reactive power to increase the bus voltage of the DC bus, aiming to correct the grid power factor to the target value (such as 0.98) or above, and ensure the reliability of grid load power consumption.

[0035] It can be seen that by configuring a heat sink integrated on the DC / DC power module and a TEG deployed on the surface of the heat sink, heat dissipation from the heat sink to the DC / DC power module can be achieved. In particular, by connecting the output terminals of the DC / DC power module and the TEG in parallel to the DC bus, the waste heat generated by the DC / DC power module can be directly converted into DC power on the DC bus. This can effectively recover and utilize the waste heat during high-power charging, which is conducive to further reducing heat dissipation energy consumption. Furthermore, the central controller can control the DCA to switch to the corresponding power buffer mode or reactive power compensation mode through capacitor topology reconstruction based on the power demand of the vehicle battery, combined with the real-time grid voltage and real-time power factor. Compared with related existing technologies, the overall power can be adaptively adjusted by switching the working mode of the charger, without the need for additional reactive power compensation cabinets or peak energy storage cabinets. This not only meets the diverse scenario requirements of the charger and improves the energy efficiency of the charger, but also significantly reduces the application cost.

[0036] Understandably, by sharing a DC bus between the TEG, DCA, and DC / DC power modules, an integrated topology is constructed, thereby reducing the number of power conversion stages and effectively improving charging efficiency. Both the TEG and DCA can be designed, but are not limited to, in "standard brick" size, supporting plug-and-play maintenance. Multiple chargers can be connected in parallel, enabling automatic resource sharing between the DCA and TEG, smooth expansion of power levels, and eliminating the need to redesign the heat dissipation or reactive power compensation system, thus achieving "plug-and-play" capacity expansion.

[0037] In one embodiment, the central controller, as the main control terminal, can sample grid voltage, grid current, power factor, vehicle battery power demand, TEG power, DCA state of charge, uniformly allocated grid power, and DCA charging and discharging power according to the actual application scenario requirements. The sampling method can be various, such as CAN, RS485, etc., which will not be elaborated here.

[0038] In one embodiment, there can be multiple DC / DC power modules and their corresponding heat sinks and TEGs. The specific number can be set according to the actual application scenario. For example, Figure 2 As shown, a three-phase configuration is typically used, which includes three DC / DC power modules connected in parallel to the DC bus. Each DC / DC power module is equipped with one TEG and one heat sink.

[0039] In one embodiment, such as Figure 3 As shown, DCA includes a high-speed switching matrix and a supercapacitor bank. The high-speed switching matrix is ​​connected to the central controller and the supercapacitor bank respectively. The high-speed switching matrix is ​​used to adjust the real-time topology state of the supercapacitor bank according to the control instructions from the central controller. The supercapacitor bank may include, but is not limited to, multiple supercapacitors.

[0040] Specifically, refer to Figure 4 Control commands from the central controller can be power commands or reactive power commands. Power commands instruct the high-speed switching matrix to switch to buffer mode, while reactive power commands instruct the high-speed switching matrix to switch to compensation mode. The DC bus is configured as a 1000V DC bus, capable of connecting at least one charging gun, supporting continuous full-load operation of a single gun at 250A / 1000V. Multiple chargers can have their DC buses connected in parallel. (See reference...) Figure 4 The "ring bus" formed by the parallel connection of multiple charger DC buses (i.e.) Figure 4 (As shown by the dashed line in the middle), for example, taking a 1.2MW parallel charging pile as an example, five 240kW standard chargers are connected in parallel on the DC bus. The central controller adopts a master-slave architecture. The DCA drawer of the newly added charger can share SOC information with the existing drawers. The central controller automatically synchronizes current sharing. The specifications of the 240kW standard charger here can be: 6×40kW DC / DC power modules, 1×TEG subarray, 1×DCA drawer (86kJ), with a volume of 600mm×800mm×1800mm. It can be seen that by paralleling, the power of the whole machine can be smoothly expanded without the need to add an additional reactive power compensation cabinet or peak energy storage cabinet, and the expansion cost is greatly reduced.

[0041] And, as Figure 4 As shown, the power adaptive charger is also equipped with a reverse protection diode. The output of the TEG is connected to the DC bus through the reverse protection diode to prevent backflow from the bus and ensure that the TEG can be stably connected to the DC bus, reducing its application failure rate. One side of the heat sink can be connected to the cooling fan through a pre-set air duct. Since the waste heat is efficiently converted into electrical energy, the average speed of the cooling fan decreases, the noise of the whole machine decreases, the charging station environment will be quieter at night, and the heat dissipation power consumption will be reduced, which will reduce carbon dioxide emissions and meet the requirements for the construction of green charging stations.

[0042] Preferably, the heat sink may be, but is not limited to, an aluminum spade heat sink with a black anodized surface; TEG is applied to one side of the heat sink using a ceramic substrate and thermal grease.

[0043] In one embodiment, the model and configuration of the TEG and DCA are not limited and can be selected according to the actual scenario. For example, the TEG can be, but is not limited to, the following:

[0044] Commercial Bi2Te3 module, model 40mm×40mm, temperature resistance ≤200℃, single-chip open circuit voltage ≈8V, maximum power point voltage ≈4V; electrically, 8 series and 5 parallel subarrays are formed, the subarray open circuit voltage is 32V, and the peak power is 120W; in terms of safety, a 60℃ normally closed temperature control switch, over-temperature bypass, etc. can be added.

[0045] DCA may, but is not limited to, using:

[0046] The supercapacitor is 3V / 100F with an ESR of 8mΩ; the array uses 96 series and 4 parallel arrays, with a total energy of approximately 86kJ, a rated voltage of 288V, and a maximum continuous current of 250A; the switching matrix uses 200V / 80A MOSFETs with a switching frequency of 20kHz and a reconstruction time of ≤2ms; for voltage equalization, it is based on an active bypass resistor plus a voltage sampling circuit, with an equalization current of 50mA and a single-cell voltage difference of ≤50mV.

[0047] In one embodiment, reference is made to Figure 4 The power adaptive charger also includes an EMI filter unit that acts as an AC input filter and a PFC topology for PFC voltage conversion. The input of the EMI filter unit is connected to the AC input voltage, and the output of the EMI filter unit is connected to the DC / DC power module through the PFC topology. The AC input here can be 380V.

[0048] In one embodiment, when the central controller controls the DCA to switch to power buffer mode, the high-speed switching matrix is ​​specifically used to: switch multiple supercapacitors to a parallel connection, specifically, as follows: Figure 5 As shown, the high-speed switching matrix uses a high-speed MOSFET matrix. Through parallel switching, all supercapacitors (all with a specification of 3V / 100F) are connected in parallel. This connection method has low equivalent resistance and can achieve high current discharge. The discharge current then passes through the main discharge contactor and current sensor to finally reach the charging gun.

[0049] In one embodiment, when the central controller controls the DCA to switch to reactive power compensation mode, the high-speed switching matrix is ​​specifically used to: switch multiple supercapacitors to a series connection in an H-bridge chain manner, specifically, as follows: Figure 6 As shown, a single-phase topology is used as an example for explanation (the same applies to multi-phase topology, which will not be elaborated here). A four-stage static synchronous compensator (STATCOM) is used to establish an H-bridge chain connection for all supercapacitors (all with a specification of 3V / 100F), which drives four IGBTs. In this connection method, reactive power can be output to compensate the power grid. The central controller can trigger the high-speed switching matrix through optical fiber, but is not limited to this.

[0050] In one embodiment, the central controller is specifically used for:

[0051] If the obtained vehicle battery power demand is less than the preset maximum grid output power limit, the DCA is switched to power buffer mode.

[0052] or,

[0053] If the real-time grid voltage drop reaches the preset voltage drop value or the real-time power factor is less than the preset minimum power factor, the DCA is controlled to switch to reactive power compensation mode.

[0054] In one embodiment, when the central controller controls the DCA to switch to reactive power compensation mode, the TEG is used to continuously generate electricity to supplement the energy consumption of the DCA, so that the real-time state of charge of the DCA is maintained at a preset range level.

[0055] Understandably, the maximum power output limit of the power grid, the voltage drop magnitude, the minimum power factor, and the preset range level can be set according to the actual scenario, and there are no restrictions here.

[0056] The following combination Figures 4-6 Explain the DCA switching principle of this power adaptive charger.

[0057] First, in standby mode, TEG uses the residual heat from the heatsink to float charge the DCA, maintaining the SOC at 70%; the cooling fan runs at low speed, and the mains only provides less than 60W of standby power.

[0058] Then, once the charging gun is engaged, if the central controller determines that the vehicle battery requires approximately 187kW of power (250A / 750V), and the maximum output power of the power grid is only 150kW, the central controller will determine a shortfall of 37kW. After 20 seconds, the central controller will control the high-speed switching matrix to switch to the power buffer mode at the millisecond level. Then, the DCA will discharge, causing the bus voltage to drop to less than 5%, until the vehicle completes the insulation test and finally maintains constant current charging.

[0059] Then, during the charging process, when the grid voltage drops by 400V or the power factor drops to 0.92 (less than 0.98), considering the possibility of grid pollution at this time, the central controller immediately switches the DCA to reactive power compensation mode to output 40kW of inductive reactive power to support the grid voltage and improve the power factor. During this process, the TEG continuously generates 4kW of power to prioritize supplementing the DCA energy consumption, keeping its SOC within the preset range of 55% to 75%.

[0060] Finally, after charging is complete, the DCA has 45% remaining energy. The TEG will recharge at 4kW, and the DCA energy is expected to return to 70% after 6 minutes. The cooling fan speed will automatically decrease as the temperature drops, and the entire system will return to standby mode.

[0061] As can be seen, compared with the existing technologies where thermal management, power factor correction and peak power support are completed by separate subsystems, the embodiments of the present invention do not require additional system management. They can achieve all the power functions required during the charging process through the integrated power adaptive charger, which can avoid hardware redundancy, reduce application costs and improve synergy.

[0062] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A power adaptive charger based on combined heat and power and topology reconfiguration, characterized in that, The power adaptive charger is configured with a DC bus and a charging gun, and an output end of the DC bus is connected to the charging gun. The heat and power cogeneration layer comprises a DC / DC power module, a heat sink integrated on the DC / DC power module, and a thermoelectric generator arranged on one side of the heat sink, and an output end of the DC / DC power module and an output end of the thermoelectric generator are connected in parallel to the DC bus. The dynamic capacitor array is connected to the DC bus and can realize capacitor topology reconfiguration. The central controller is connected to the dynamic capacitor array and is used to control the dynamic capacitor array to switch to a power buffer mode or a reactive power compensation mode according to the acquired vehicle battery demand power, the real-time power grid voltage and the real-time power factor. In the power buffer mode, the dynamic capacitor array discharges to reduce the bus voltage of the DC bus, and in the reactive power compensation mode, the dynamic capacitor array outputs reactive power to increase the bus voltage of the DC bus.

2. The power adaptive charger based on combined heat and power and topology reconfiguration of claim 1, wherein, The dynamic capacitor array comprises a high-speed switching matrix and a super capacitor group, the high-speed switching matrix is connected to the central controller and the super capacitor group respectively, and the high-speed switching matrix is used to adjust the real-time topology state of the super capacitor group according to the control instruction from the central controller.

3. The power adaptive charger based on combined heat and power and topology reconfiguration of claim 2, wherein, The super capacitor group comprises a plurality of super capacitors. In the case where the central controller controls the dynamic capacitor array to switch to the power buffer mode, the high-speed switching matrix is specifically used to switch a plurality of the super capacitors to be connected in parallel. Or, In the case where the central controller controls the dynamic capacitor array to switch to the reactive power compensation mode, the high-speed switching matrix is specifically used to switch a plurality of the super capacitors to be connected in series in an H-bridge chain.

4. The power adaptive charger based on combined heat and power and topology reconfiguration of claim 1, wherein, The central controller is specifically used to: In the case where it is determined that the acquired vehicle battery demand power is less than a preset maximum limited output power of the power grid, control the dynamic capacitor array to switch to the power buffer mode.

5. The power adaptive charger based on combined heat and power and topology reconfiguration of claim 1, wherein, The central controller is specifically used to: In the case where it is detected that a reduction amplitude of the real-time power grid voltage reaches a preset voltage reduction amplitude or the real-time power factor is less than a preset minimum power factor, control the dynamic capacitor array to switch to the reactive power compensation mode.

6. The power adaptive charger based on combined heat and power and topology reconfiguration of claim 5, wherein, In the case where the central controller controls the dynamic capacitor array to switch to the reactive power compensation mode, the thermoelectric generator is used to continuously generate power to supplement the energy consumption of the dynamic capacitor array, so that the real-time state of charge of the dynamic capacitor array is maintained at a preset interval level. 7.The power adaptive charger based on combined heat and power and topology reconfiguration of claim 1, wherein, The EMI filter unit and the PFC topology are further included, an input end of the EMI filter unit is connected to a mains input voltage, and an output end of the EMI filter unit is connected to the DC / DC power module through the PFC topology. 8.The power adaptive charger based on combined heat and power and topology reconfiguration of claim 1, wherein, The anti-reverse diode is further included, and the output end of the thermoelectric generator is connected to the DC bus through the anti-reverse diode. 9.The power adaptive charger based on combined heat and power and topology reconfiguration of claim 2 or 3, wherein, The central controller triggers the high-speed switching matrix through an optical fiber.

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