A medium- and low-voltage on-board charging and inverter integrated system

Abstract

This invention relates to the field of on-board charging technology, specifically to a medium- and low-voltage on-board charging and inverter integrated system. The system includes a bidirectional inverter and a base. A heat-conducting platform is fixedly mounted on the rear end of the upper surface of the base. A main control board is fixedly mounted on the four corners of the upper surface of the base. Components on the lower surface of the main control board are embedded in the heat-conducting platform. The main control board also includes a bidirectional inverter unit, a medium- and low-voltage conversion unit, and an integrated control unit. The bidirectional inverter unit is used for switching between forward charging and reverse discharging modes of the bidirectional inverter. The integrated control unit is used to monitor and acquire real-time operating parameters of the bidirectional inverter circuit, determine the circuit operating status, and transmit the circuit operating status information to the medium- and low-voltage conversion unit. The medium- and low-voltage conversion unit controls the circuit voltage conversion and adjustment based on the received circuit operating status information. This invention features stable charging and high conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of vehicle charging technology, and more specifically, to a medium- and low-voltage vehicle charging and inverter integrated system. Background Technology

[0002] Bidirectional on-board charger (OBC) refers to a bidirectional on-board charger equipped in electric vehicles. It is an advanced power conversion system capable of enabling bidirectional flow of electrical energy. Unlike traditional unidirectional OBCs that can only convert AC power from the grid to DC power to charge the battery, bidirectional inverter chargers can not only "charge" but also "discharge," inverting the DC power from the vehicle's battery back to AC power for external use.

[0003] Existing on-board charging and inverter integrated systems combine inverter and charging functions. During the conversion between DC and AC power, energy loss is easily generated. Compared with DC fast charging technology, its overall energy efficiency leads to the waste of vehicle power. At the same time, electromagnetic interference is easily generated during the inverter process, which affects the normal operation of the system.

[0004] Based on this, a medium- and low-voltage on-board charging and inverter integrated system is proposed. Summary of the Invention

[0005] The main objective of this invention is to provide a medium- and low-voltage on-board charging and inverter integrated system to overcome the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides a medium- and low-voltage on-board charging and inverter integrated system, including a bidirectional inverter. The bidirectional inverter also includes an aluminum alloy base. A heat conduction platform is provided in the middle of the upper surface of the aluminum alloy base. A main control board is fixedly mounted on the four corners of the upper surface of the aluminum alloy base. Components are embedded in the heat conduction platform on the lower surface of the main control board. The main control board also includes a bidirectional inverter unit, a medium- and low-voltage conversion unit, and an integrated control unit.

[0007] The bidirectional inverter unit is used to switch between the forward charging mode and the reverse discharging mode of the bidirectional inverter, and transmits the current circuit mode information of the bidirectional inverter to the integrated control unit.

[0008] The integrated control unit is used to monitor and acquire the real-time operating parameters of the bidirectional inverter circuit, sum and calculate the operating parameters to obtain the operating status index, set the operating status index threshold, construct a threshold range based on the operating status index threshold, match the operating status index with the threshold range to obtain the matching index, determine the circuit operating status of the bidirectional inverter according to the matching index, and transmit the circuit operating status information to the medium and low voltage conversion unit.

[0009] The medium-low voltage conversion unit controls the circuit voltage to adjust based on the received circuit operating status information.

[0010] As a further improvement of the present invention, fixed supports are fixedly provided at the four corners of the lower surface of the aluminum alloy base, a cooling fan is embedded in the middle of the lower surface of the aluminum alloy base, a mesh cover is provided below the cooling fan, the four corners of the mesh cover are fixedly connected to the lower surface of the aluminum alloy base, and the cooling fan is electrically connected with wires, the other end of the wires passing through the base and electrically connected to the main control board.

[0011] As a further improvement of the present invention, ceramic sheets are fixedly installed on the upper part of the rear end and one side of the outer surface of the heat conduction platform, and pressure strips are fixedly installed on the lower part of the rear end and one side of the outer surface of the heat conduction platform. The pressing end of the pressure strip abuts the main heat-generating electronic components on the circuit board against the outer surface of the ceramic sheet and presses them firmly onto the aluminum alloy base. MOS transistors are electrically connected to the front end and one side of the lower surface of the main control board. The MOS transistors are all clamped between the contact parts of the pressure strip and the ceramic sheet.

[0012] As a further improvement of the present invention, a signal light board is provided at the front end of the MOS transistor, the signal light board is electrically fixedly connected to the main control board, and a plurality of signal lights are electrically connected to one side of the front end of the outer surface of the signal light board.

[0013] As a further improvement of the present invention, an injection-molded shell is fixedly installed on the upper surface of the aluminum alloy base. Several sets of slots are opened at the front ends of both sides of the outer surface of the injection-molded shell. An opening is opened at the middle of the front end of the outer surface of the injection-molded shell. An indicator plate is fixedly installed on the inner surface of the injection-molded shell through the opening. A light-shielding block is fixedly installed at the middle of the rear end of the outer surface of the indicator plate. Several light-transmitting holes are opened through the front ends of the outer surfaces of the indicator plate and the light-shielding block, corresponding to the signal lights. A signal light film is pasted and fixedly installed on the front end of the outer surface of the indicator plate. A wire harness is inserted and installed on the inner surface of the injection-molded shell through the slots. A structural component is injection-molded on the outer surface of the wire harness. The injection-molded structural component is fixedly connected to the slots.

[0014] As a further improvement of the present invention, the switching between the forward charging mode and the reverse discharging mode of the bidirectional inverter is specifically as follows:

[0015] The bidirectional inverter unit also includes an AC conversion relay, an AC EMI filter, and a DC relay;

[0016] The AC conversion relay is used for intelligent switching between forward charging mode and reverse discharging mode, and includes a power status detection module, a PLC controller and a relay group;

[0017] The power status detection module uses a differential voltage comparator to monitor the main power supply voltage in real time and presets a main power supply voltage threshold. And construct the main power supply voltage threshold range ( When the monitored real-time main power supply voltage is within the threshold range, it indicates that the voltage is normal and triggers the forward charging signal; when the monitored real-time main power supply voltage is greater than the maximum value of the threshold range, it indicates that the voltage is normal and triggers the forward charging signal. When the voltage is abnormal, it indicates that the power supply signal has been interrupted. This occurs when the monitored real-time main power supply voltage is lower than the minimum value of the threshold range. When the voltage is abnormal, it indicates that a switching signal is triggered, switching to the reverse discharge mode of the battery. The forward charging signal, the power supply blocking signal, and the switching signal are all generated by the PLC controller and transmitted to the relay group.

[0018] The relay group uses two sets of AC contactors KM1 and KM2 and one set of relays K1. If the current received control command is a positive charging signal, the positive path turns on the main power supply and KM1 is energized, and the current flows to charge the battery. If the current received control command is a power blocking signal, KM1 and KM2 close to block the power supply. If the current received control command is a switching signal, the reverse path turns off the main power supply, K1 resets and triggers KM2 to energize, and the battery supplies power to the load through the inverter circuit.

[0019] AC EMI filters are used to filter EMC and EMI interference; DC relays are used to prevent reverse power connection and surges.

[0020] As a further improvement of the present invention, the operating parameters are summed to obtain the operating state index, specifically:

[0021] The operating parameters are analyzed to obtain real-time voltage, current, and power data, which are then normalized and input into the formula. Obtain the running status index DY, DL, and GL represent the real-time voltage, current, and power values, respectively. These are respectively represented as the set weighting factors;

[0022] Set voltage, current, and power thresholds, normalize them, and then input them into the formula. Obtain the operating state index threshold , The threshold values ​​for voltage, current, and power are respectively used to select the operating state index threshold. The maximum to minimum values ​​within the affected range constitute the threshold range of the operating status index. );

[0023] running status index With the operating status index threshold range ( Matching is performed if... Then a matching index is generated. This indicates that the circuit voltage is operating normally. ,and Then generate the matching index This indicates that the circuit voltage is abnormally high or low, and transmits the circuit voltage operating status information to the medium and low voltage conversion unit.

[0024] As a further improvement of the present invention, the circuit voltage is controlled to be adjusted based on the received circuit voltage operating status information, specifically as follows:

[0025] The medium- and low-voltage conversion unit also includes a combination of PFC circuit, dual active bridge (DAB) circuit, and synchronous rectifier circuit;

[0026] The pre-stage voltage regulator, PFC circuit is responsible for coarse adjustment of bus voltage, dynamic feedback network is used to realize adjustment range control, and feedforward compensation mechanism is integrated to suppress transient overshoot;

[0027] Power distribution: The dual active bridge (DAB) uses a power controller to collect input and output voltage and load current data in real time, and distributes power based on a dynamic phase-shifting strategy that switches between actual power and critical power.

[0028] The output is finely tuned, and the synchronous rectifier circuit controls the output voltage deviation through an adaptive dead-time compensation control circuit.

[0029] The beneficial effects of this invention are:

[0030] This invention integrates OBC and inverter, meeting users' charging needs while also providing emergency power for vehicles or outdoors. By setting up a bidirectional inverter unit, it can automatically switch between forward charging and reverse discharging modes based on the voltage parameters at the output of the bidirectional inverter, and has the effect of reducing energy loss during the conversion process, thereby ensuring conversion efficiency. At the same time, it can automatically detect and stabilize and correct abnormal circuit voltages during the input process to avoid damage to the equipment caused by abnormal circuit voltages during charging and discharging. It features stable charging and high conversion efficiency. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 This is a schematic diagram of the front three-dimensional structure of the present invention;

[0033] Figure 2 This is a bottom view of the present invention;

[0034] Figure 3 This is a top view of the injection-molded housing structure of the present invention before disassembly;

[0035] Figure 4 This is a bottom view of the disassembled injection-molded housing structure of the present invention;

[0036] Figure 5 This is an internal schematic diagram of the present invention;

[0037] Figure 6 This is a schematic diagram of the aluminum alloy base structure of the present invention from the front side after disassembly;

[0038] Figure 7 This is a schematic diagram of the aluminum alloy base structure after disassembly according to the present invention;

[0039] Figure 8 This is a schematic diagram of the main control board of the present invention disassembled;

[0040] Figure 9 This is a split bottom view of the main control board of the present invention;

[0041] Figure 10 This is a system principle block diagram of the present invention.

[0042] In the diagram: 1. Aluminum alloy base; 101. Cooling fan; 102. Mesh cover; 103. Heat conduction platform; 104. Ceramic sheet; 105. Pressure strip; 2. Injection molded housing; 201. Bayonet; 202. Indicator plate; 203. Light-transmitting hole; 204. Light-shielding block; 205. Signal light film; 3. Wiring harness; 301. Wiring harness structural component; 4. Main control board; 401. MOSFET; 5. Signal light board; 501. Signal light. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0047] Please see Figures 1-10 As shown, a medium-low voltage vehicle charging and inverter integrated system includes a bidirectional inverter, which also includes an aluminum alloy base 1. A heat conduction platform 103 is provided at the rear end of the upper surface of the aluminum alloy base 1. Components on the lower surface of the main control board 4 are embedded in the heat conduction platform 103. The main control board 4 is fixedly mounted on the four corners of the upper surface of the aluminum alloy base 1. Fixing brackets are fixedly provided at the four corners of the lower surface of the aluminum alloy base 1. A cooling fan 101 is embedded in the middle of the lower surface of the aluminum alloy base 1. A mesh cover 102 is provided below the cooling fan 101. The four corners of the mesh cover 102 are fixedly connected to the lower surface of the aluminum alloy base 1. The cooling fan 101 is electrically connected with wires, and the other end of the wires passes through the aluminum alloy base 1 and is electrically connected to the main control board 4.

[0048] It should be noted that the aluminum alloy base 1, together with the heat conduction platform 103, is used to support and install the internal components of the bidirectional inverter. The main control board 4 realizes the operation control of the entire bidirectional inverter. Since there is a wire connecting the cooling fan 101 and the main control board 4, the cooling fan 101 can be electrically controlled by the main control board 4 to rotate. Thus, the cooling fan 101 is used to dissipate heat and cool the inside of the base 1, indirectly achieving the air cooling effect of the bidirectional inverter. The mesh cover 102 can protect the blades of the cooling fan 101. At the same time, the components on the main control board 4 are all embedded in the heat conduction platform 103. The heat conduction platform 103 can absorb the heat generated by the components during operation, achieving the effect of forced heat dissipation.

[0049] Ceramic sheets 104 are fixedly installed on the upper part of the rear end and one side of the outer surface of the heat conduction platform 103. Pressure strips 105 are fixedly installed on the lower part of the rear end and one side of the outer surface of the heat conduction platform 103. The pressing end of the pressure strip 105 abuts against the outer surface of the ceramic sheet 104. MOS transistors 401 are electrically connected to the front end and one side of the lower surface of the main control board 4. MOS transistors 401 are all clamped between the pressure strip 105 and the contact part of the ceramic sheet 104. A signal light board 5 is provided at the front end of the MOS transistor 401. The signal light board 5 is electrically fixedly connected to the main control board 4. Several signal lights 501 are electrically connected to one side of the front end of the outer surface of the signal light board 5.

[0050] It should be noted that the ceramic plate 104 is made of ceramic material, which has good thermal conductivity and insulation effect. By attaching the MOS transistor 401 set on the main control board 4 to the ceramic plate 104, the ceramic plate 104 can absorb and conduct the heat generated by the MOS transistor 401 during operation. The pressure strip 105 is used to elastically press the MOS transistor 401 to ensure that the MOS transistor 401 is stably attached to the ceramic plate 104 for heat dissipation and cooling.

[0051] By setting up an indicator light board 5 and multiple sets of indicator lights 501, each set of indicator lights 501 represents a different signal, and the current operating status of the bidirectional inverter can be determined by the indication of the indicator lights 501.

[0052] A molded housing 2 is fixedly installed on the upper surface of the aluminum alloy base 1. Several sets of slots 201 are opened on the front ends of both sides of the outer surface of the molded housing 2. An opening is opened in the middle of the front end of the outer surface of the molded housing 2. An indicator plate 202 is fixedly installed on the inner surface of the molded housing 2 through the opening. A light-shielding block 204 is fixedly installed in the middle of the rear end of the outer surface of the indicator plate 202. Several light-transmitting holes 203 are opened through the front ends of the outer surfaces of the indicator plate 202 and the light-shielding block 204, corresponding to the signal light 501. A signal light film 205 is pasted and fixedly installed on the front end of the outer surface of the indicator plate 202. A wire harness 3 is inserted and installed on the inner surface of the molded housing 2 through the slots 201. A wire harness structure 301 is injection molded on the outer surface of the wire harness 3. The wire harness structure 301 is fixedly connected to the slots 201.

[0053] It should be noted that by setting the injection-molded housing 2 to cover the outside of the main control board 4, the main control structure of the bidirectional inverter can be protected. The indicator plate 202 set on the injection-molded housing 2 is aligned with the signal lamp 501 set on the signal lamp board 5. At this time, the light-shielding block 204 set at the rear end of the indicator plate 202 can cover the light-transmitting hole 203 of the signal lamp 501. The covering of the light-shielding block 204 can cover the light scattering range of the signal lamp 501, thereby ensuring that the light is concentrated in the light-transmitting hole 203 and improving the brightness of the indicator light 501. The signal lamp film 205 attached to the front end of the indicator plate 202 records the corresponding light indication content of the signal lamp 501. The wire harness 3 that is attached to the injection-molded housing 2 is used for the energy supply transmission of the bidirectional inverter.

[0054] The main control board 4 is also equipped with a bidirectional inverter unit, a medium-low voltage conversion unit, and an integrated control unit;

[0055] The bidirectional inverter unit is used to switch between the forward charging mode and the reverse discharging mode of the bidirectional inverter, and transmits the current circuit mode information of the bidirectional inverter to the integrated control unit.

[0056] The switching between forward charging mode and reverse discharging mode of the bidirectional inverter is as follows:

[0057] The bidirectional inverter unit also includes an AC conversion relay, an AC EMI filter, and a DC relay;

[0058] The AC conversion relay is used for intelligent switching between forward charging mode and reverse discharging mode, and includes a power status detection module, a PLC controller and a relay group;

[0059] The power status detection module uses a differential voltage comparator to monitor the main power supply voltage in real time and presets a main power supply voltage threshold. And construct the main power supply voltage threshold range ( When the monitored real-time main power supply voltage is within the threshold range, it indicates that the voltage is normal and triggers the forward charging signal; when the monitored real-time main power supply voltage is greater than the maximum value of the threshold range, it indicates that the voltage is normal and triggers the forward charging signal. When the voltage is abnormal, it indicates that the power supply signal has been interrupted. This occurs when the monitored real-time main power supply voltage is lower than the minimum value of the threshold range. When the voltage is abnormal, it indicates that a switching signal is triggered, switching to the reverse discharge mode of the battery. The forward charging signal, the power supply blocking signal, and the switching signal are all generated by the PLC controller and transmitted to the relay group.

[0060] The relay group uses two sets of AC contactors KM1 and KM2 and one set of relays K1. If the current received control command is a positive charging signal, the positive path turns on the main power supply and KM1 is energized, and the current flows to charge the battery. If the current received control command is a power blocking signal, KM1 and KM2 close to block the power supply. If the current received control command is a switching signal, the reverse path turns off the main power supply, K1 resets and triggers KM2 to energize, and the battery supplies power to the load through the inverter circuit.

[0061] Charging mode (normal main power supply): When the K1 coil is energized, the normally open contact closes (the KM2 coil is de-energized), and then the normally closed contact opens (the KM1 coil is energized), so that the main power supply charges the battery through KM1.

[0062] Discharge mode (main power failure): K1 power failure reset control normally closed contact closes (KM1 power failure), then controls normally open contact reset (KM2 power on), so that the battery supplies power to the load through the inverter via KM2;

[0063] AC EMI filters are used to filter EMC and EMI interference to prevent incompatibility problems caused by interference or being interfered with.

[0064] The specific implementation is as follows: Common-mode inductors and differential-mode inductors, as well as common-mode capacitors and differential-mode capacitors, are used to suppress asymmetrical interference between the live wire, neutral wire, and ground wire for common-mode interference. The common-mode inductor provides high impedance to block noise, and the common-mode capacitor connects the live wire, neutral wire, and ground wire, providing a low-impedance path for common-mode noise to ground and diverting the noise to the grounding path. For differential-mode interference, high-frequency noise between the live wire and neutral wire is suppressed. A low-pass filter is formed by bridging the live wire, neutral wire, and differential-mode inductor with a differential-mode capacitor. The capacitor short-circuits high-frequency noise, and the inductor impedance attenuates the interference signal.

[0065] DC relays are used to prevent reverse power connection and surges, thereby protecting circuits and equipment.

[0066] The specific implementation method is as follows: To prevent reverse power connection, a diode is connected in series in the relay excitation coil circuit, utilizing its unidirectional conductivity: when the power supply is connected in the forward direction, current flows through the diode and coil, the relay is energized, and the contacts switch to conduct the load circuit; when the power supply is reverse connected, the diode is reverse cut off, the coil cannot be energized, and the contacts remain in a normally open or normally closed state, which can be set according to actual usage requirements, thereby blocking the reverse current from flowing into the downstream circuit and protecting the equipment from damage.

[0067] To prevent surge protection, a surge relay structure is adopted, such as the ZC23 type, which integrates a pulse converter and an actuator, such as a reed relay: when the circuit experiences overload, short circuit or sudden current change, the pulse converter senses the sudden change and generates a pulse signal, triggering the actuator to act and quickly disconnect the load circuit, avoiding damage to the core components from the instantaneous large current surge.

[0068] The integrated control unit is used to monitor and acquire the real-time operating parameters of the bidirectional inverter circuit, sum and calculate the operating parameters to obtain the operating status index, set the operating status index threshold, construct a threshold range based on the operating status index threshold, match the operating status index with the threshold range to obtain the matching index, determine the circuit operating status of the bidirectional inverter according to the matching index, and transmit the circuit operating status information to the medium and low voltage conversion unit.

[0069] The operating parameters are summed to obtain the operating status index, specifically:

[0070] The operating parameters are analyzed to obtain real-time voltage, current, and power data, which are then normalized and input into the formula. Obtain the running status index DY, DL, and GL represent the real-time voltage, current, and power values, respectively. These are respectively represented as the set weighting factors;

[0071] Set voltage, current, and power thresholds, normalize them, and then input them into the formula. Obtain the operating state index threshold , The threshold values ​​for voltage, current, and power are respectively used to select the operating state index threshold. The maximum to minimum values ​​within the affected range constitute the threshold range of the operating status index. );

[0072] running status index With the operating status index threshold range ( Matching is performed if... Then a matching index is generated. This indicates that the circuit voltage is operating normally. ,and Then generate the matching index This indicates that the circuit voltage is abnormally high or low, and transmits the circuit voltage operating status information to the medium and low voltage conversion unit.

[0073] The medium-low voltage conversion unit controls the circuit voltage to adjust and convert based on the received circuit voltage operating status information, specifically:

[0074] The medium- and low-voltage conversion unit also includes a combination of PFC circuit, dual active bridge (DAB) circuit, and synchronous rectifier circuit;

[0075] The pre-stage voltage regulator, PFC circuit is responsible for coarse adjustment of bus voltage, dynamic feedback network is used to realize adjustment range control, and feedforward compensation mechanism is integrated to suppress transient overshoot;

[0076] By changing the voltage divider network at the PFC output ( The ratio of the feedback voltage is adjusted. R1 and R2 are two resistors in a resistor divider network at the output of the PFC circuit. R1 refers to the pull-up resistor, and R2 refers to the pull-down resistor. They are connected in series in the PFC output voltage divider network. Between and the earth;

[0077] Increase R1 or decrease R2 according to the formula Obtain the partial pressure ratio It becomes smaller, thus leading to Lower, in order to Pulling back the reference voltage will boost the PFC chip. Therefore, the output voltage It will rise;

[0078] Decrease R1 or increase R2 according to the formula Obtain the partial pressure ratio Increase in size, thus leading to To raise, in order to Pulling back the reference voltage will reduce the PFC chip's voltage. Make The voltage drops, therefore the output voltage... It will decrease;

[0079] The increase or decrease of the ratio of R1 or R2 is controlled by connecting the output of the digital-to-analog converter (DAC) to the feedback pin of the PFC control chip. The microcontroller (MCU) calculates and generates a corresponding digital code, and the DAC then produces a precise analog voltage based on this code. The PFC chip forces its feedback pin voltage to equal the voltage from the DAC. It can automatically output the real-time circuit voltage Adjust to the appropriate level;

[0080] For power distribution, the dual active bridge (DAB) uses a power controller to collect input and output voltage and load current data in real time. Based on the dynamic phase-shifting strategy of actual power and critical power, when the actual power is less than the critical power, the minimum return power mode is activated to reduce circulating current loss. When the actual power is greater than the critical power, a collaborative optimization mode is used to iteratively solve for the optimal phase shift, which improves the response speed by 40% and reduces current stress by 15%, while maintaining zero-voltage switching conditions to achieve a peak efficiency of 98.8%.

[0081] The power bidirectional flow control system uses a dual active bridge circuit consisting of two H-bridge circuits, connected to the input source and output load respectively. The input-side H-bridge converts DC power into a high-frequency AC square wave voltage, while the output-side H-bridge converts the AC square wave back to DC power. A high-frequency transformer is placed between the two bridges for electrical isolation and voltage transformation. The transformer, with its external inductor, serves as the core carrier for energy transmission; its current change rate determines the direction and magnitude of power transmission. Phase-shift modulation adjusts the phase difference of the bridge voltage waveform: for forward transmission, the input-side H-bridge voltage phase leads the output phase, with a phase difference of [missing information]. At this time, energy flows from the input to the output, and is transferred in the reverse direction. The phase of the H-bridge voltage on the output side leads that on the input side, and the phase difference is... At this time, energy flows from the output to the input, where the transmitted power is related to the phase shift angle. Positive correlation , When the value is zero, the power is zero, and only circulating current loss exists;

[0082] Secondly, by utilizing the external inductor current of the transformer, during the dead time of the switching transistor, the inductor current charges and discharges the junction capacitance of the switching transistor, causing the voltage across its terminals to drop to zero before it is turned on again, thereby significantly reducing switching losses.

[0083] Critical power determination: Bus voltage is collected by setting the power controller. Load current and isolation side output voltage Based on real-time power With critical power Switch modes, if If minimum return power control is used to reduce circulating current loss, then... Then, the recirculation function and current stress are optimized together, and the optimal displacement ratio is solved iteratively by the momentum method.

[0084] Output fine-tuning, synchronous rectification circuit enhances output stability, receives DAB output, and power controller detects output current. and MOSFET switch drain-source voltage Set precise dead time and use adaptive dead time compensation. Calculate adaptive dead time This allows for adjustment of the dead time based on real-time operating current and voltage, ensuring that the complementary drive MOSFETs do not conduct simultaneously. This helps optimize converter efficiency across the entire load range by minimizing body diode conduction and promoting zero-voltage switching. It enables the power system to adapt to a wide range of voltage and load variations, achieving a balance between reliability and performance, and eliminating voltage drops caused by reverse recovery. K is a safety factor, typically ranging from 1.2 to 1.5. The output capacitor of the MOSFET switch;

[0085] Secondly, the synchronous rectification circuit can use power MOSFETs instead of traditional rectifier diodes to eliminate the conduction losses caused by the forward voltage drop of the diodes.

[0086] In use, the bidirectional inverter harness 3 can first connect its input and output ports to the power supply and load terminals according to the charging mode. After connection, the bidirectional inverter unit on the main control board 4 can detect the current voltage parameters of the power supply and intelligently switch the current charging mode according to the voltage parameters to ensure user needs. After the bidirectional inverter completes the charging mode switch, it can start running according to the charging mode. During operation, the integrated control unit will monitor and collect the real-time operating parameters of the bidirectional inverter, calculate and determine the current circuit operating status of the bidirectional inverter, and transmit the operating status information to the medium and low voltage conversion unit. The medium and low voltage conversion unit can correct and adjust abnormal voltages in the circuit operating status, thereby ensuring the stable operation of the bidirectional inverter in bidirectional charging mode switching, and has the characteristics of stable charging and high conversion efficiency.

[0087] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A medium- and low-voltage on-board charging and inverter integrated system, comprising a bidirectional inverter, characterized in that, The bidirectional inverter also includes an aluminum alloy base (1), a heat conduction platform (103) is fixedly installed on the rear end of the upper surface of the aluminum alloy base (1), and a main control board (4) is fixedly installed on the four corners of the upper surface of the aluminum alloy base (1). The components on the lower surface of the main control board (4) are all embedded in the aluminum alloy heat conduction platform (103). The main control board (4) is also provided with a bidirectional inverter unit, a medium and low voltage conversion unit and an integrated control unit. The bidirectional inverter unit is used to switch between the forward charging mode and the reverse discharging mode of the bidirectional inverter, and transmits the current circuit mode information of the bidirectional inverter to the integrated control unit. The integrated control unit is used to monitor and acquire the real-time operating parameters of the bidirectional inverter circuit, sum and calculate the operating parameters to obtain the operating status index, set the operating status index threshold, construct a threshold range based on the operating status index threshold, match the operating status index with the threshold range to obtain the matching index, determine the circuit operating status of the bidirectional inverter according to the matching index, and transmit the circuit operating status information to the medium and low voltage conversion unit. The medium-low voltage conversion unit controls the circuit voltage to adjust based on the received circuit operating status information.

2. The medium-low voltage on-board charging and inverter integrated system according to claim 1, characterized in that, Connecting ears are fixedly provided at the four corners of the lower surface of the aluminum alloy base (1). A cooling fan (101) is embedded and rotatably installed at the rear end of the lower surface of the aluminum alloy base (1). A mesh cover (102) is provided below the cooling fan (101). The four corners of the mesh cover (102) are fixedly connected to the lower surface of the base (1). The cooling fan (101) is electrically connected with a wire. The other end of the wire passes through the base (1) and is electrically connected to the main control board (4).

3. The medium-low voltage on-board charging and inverter integrated system according to claim 1, characterized in that, Ceramic sheets (104) are fixedly installed on the upper part of the rear end and one side of the outer surface of the heat conduction platform (103). Pressure strips (105) are fixedly installed on the lower part of the rear end and one side of the outer surface of the heat conduction platform (103). The pressing end of the pressure strip (105) abuts against the outer surface of the ceramic sheet (104). MOS transistors (401) are electrically connected to the front end and one side of the lower surface of the main control board (4). The MOS transistors (401) are all clamped between the pressure strip (105) and the contact part of the ceramic sheet (104).

4. The medium- and low-voltage on-board charging and inverter integrated system according to claim 3, characterized in that, The front end of the MOS transistor (401) is provided with a signal light board (5), which is electrically fixedly connected to the main control board (4). Several signal lights (501) are electrically connected to one side of the front end of the outer surface of the signal light board (5).

5. The medium- and low-voltage on-board charging and inverter integrated system according to claim 4, characterized in that, The upper surface of the aluminum alloy base (1) is covered with a fixed injection molded shell (2). Several sets of bayonets (201) are opened on the front ends of both sides of the outer surface of the injection molded shell (2). An opening is opened in the middle of the front end of the outer surface of the injection molded shell (2). An indicator plate (202) is fixedly installed on the inner surface of the injection molded shell (2) through the opening. A light-shielding block (204) is fixedly installed in the middle of the rear end of the outer surface of the indicator plate (202). Several light-transmitting holes (203) are opened through the front end of the outer surface of the indicator plate (202) and the light-shielding block (204) corresponding to the signal light (501). A signal light film (205) is pasted and fixedly installed on the front end of the outer surface of the indicator plate (202). A wire harness (3) is inserted and installed on the inner surface of the injection molded shell (2) through the bayonet (201). A structural component (301) is injection molded on the outer surface of the wire harness (3). The structural component (301) is fixedly connected to the bayonet (201).

6. The medium- and low-voltage on-board charging and inverter integrated system according to claim 1, characterized in that, The switching between forward charging mode and reverse discharging mode of the bidirectional inverter is as follows: The bidirectional inverter unit also includes an AC conversion relay, an AC EMI filter, and a DC relay; The AC conversion relay is used for intelligent switching between forward charging mode and reverse discharging mode, and includes a power status detection module, a PLC controller and a relay group; The power status detection module uses a differential voltage comparator to monitor the main power supply voltage in real time and presets a main power supply voltage threshold. And construct the main power supply voltage threshold range ( When the monitored real-time main power supply voltage is within the threshold range, it indicates that the voltage is normal and triggers the forward charging signal; when the monitored real-time main power supply voltage is greater than the maximum value of the threshold range, it indicates that the voltage is normal and triggers the forward charging signal. When the voltage is abnormal, it indicates that the power supply signal has been interrupted. This occurs when the monitored real-time main power supply voltage is lower than the minimum value of the threshold range. When the voltage is abnormal, it indicates that a switching signal is triggered, switching to the reverse discharge mode of the battery. The forward charging signal, the power supply blocking signal, and the switching signal are all generated by the PLC controller and transmitted to the relay group. The relay group uses two sets of AC contactors KM1 and KM2 and one set of relays K1. If the current received control command is a positive charging signal, the positive path turns on the main power supply and KM1 is energized, and the current flows to charge the battery. If the current received control command is a power blocking signal, KM1 and KM2 close to block the power supply. If the current received control command is a switching signal, the reverse path turns off the main power supply, K1 resets and triggers KM2 to energize, and the battery supplies power to the load through the inverter circuit. AC EMI filters are used to filter EMC and EMI interference; DC relays are used to prevent reverse power connection and surges.

7. The medium- and low-voltage on-board charging and inverter integrated system according to claim 1, characterized in that, The operating parameters are summed to obtain the operating status index, specifically: The operating parameters are analyzed to obtain real-time voltage, current, and power data, which are then normalized and input into the formula. Obtain the running status index DY, DL, and GL represent the real-time voltage, current, and power values, respectively. These are respectively represented as the set weighting factors; Set voltage, current, and power thresholds, normalize them, and then input them into the formula. Obtain the operating state index threshold , The threshold values ​​for voltage, current, and power are respectively used to select the operating state index threshold. The maximum to minimum values ​​within the affected range constitute the threshold range of the operating status index. ); running status index With the operating status index threshold range ( Matching is performed if... Then a matching index is generated. This indicates that the circuit voltage is operating normally. ,and Then generate the matching index This indicates that the circuit voltage is abnormally high or low, and transmits the circuit voltage operating status information to the medium and low voltage conversion unit.

8. The medium-low voltage on-board charging and inverter integrated system according to claim 1, characterized in that, The control circuit voltage is adjusted and converted based on the received circuit voltage operating status information, specifically as follows: The medium- and low-voltage conversion unit also includes a combination of a PFC circuit, a dual active bridge (DAB), and a synchronous rectifier circuit. The pre-stage voltage regulator, PFC circuit is responsible for coarse adjustment of bus voltage, dynamic feedback network is used to realize adjustment range control, and feedforward compensation mechanism is integrated to suppress transient overshoot; Power distribution: The dual active bridge (DAB) uses a power controller to collect input and output voltage and load current data in real time, and distributes power based on a dynamic phase-shifting strategy that switches between actual power and critical power. The output is finely tuned, and the synchronous rectifier circuit controls the output voltage deviation through an adaptive dead-time compensation control circuit.

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