Wireless charging system and method based on compact WPT and APM circuit topology integration

Abstract

The invention provides a wireless charging system and method based on compact WPT and APM circuit topology integration, belongs to the technical field of wireless power transmission, and aims to solve the problems that most of existing electric vehicle wireless charging systems only support charging of power batteries, auxiliary batteries are charged by depending on a vehicle-mounted independent DC-DC converter, and the charging efficiency is low. A circuit topology redundancy problem exists in mutually independent charging modes. The system comprises a ground side transmitting end, a power battery receiving end and an auxiliary battery receiving end. The wireless charging method comprises the steps that S1, the position of the electric vehicle is judged, and when the electric vehicle is located in a ground side transmitting end area, the wireless charging system enters a WPT mode to stably charge a power battery; s2, after the electric vehicle leaves the ground side transmitting terminal area, the wireless charging system is switched from the WPT mode to the APM mode to charge the auxiliary battery; and S3, according to the charging states of the power battery and the auxiliary battery, dynamically adjusting the charging current and voltage until the charging is completed.

Description

Technical Field

[0001] This invention relates to a wireless charging system and method based on the integration of a compact WPT and APM circuit topology, belonging to the field of wireless power transfer technology. Background Technology

[0002] Wireless Power Transfer (WPT) technology is one of the key enabling technologies in the new energy system. With the rapid development of industries such as smart terminal devices and electric vehicles, the application scope of this technology is gradually expanding, extending from low-power consumer electronics such as smartphones and wearable devices to industrial and transportation applications with higher power requirements, such as electric vehicles. Compared to traditional wired charging, WPT technology achieves contactless power transfer based on principles such as electromagnetic induction or magnetic resonance. This technology not only fundamentally eliminates the maintenance costs caused by wear and tear from physical interface plugging and unplugging, but also effectively avoids the potential leakage safety hazards of contact charging. Therefore, in applications with high requirements for equipment reliability, sealing, and operational safety, WPT technology demonstrates its irreplaceable technological advantages.

[0003] In the power supply system of electric vehicles, two independent energy storage units are typically configured: a high-voltage (HV) power battery and a low-voltage (LV) auxiliary battery. The high-voltage power battery, as the core power source, can be replenished via a wireless charging system from the ground-side AC grid. This technology, with its inherently contactless transmission characteristics, offers significant advantages such as high safety, ease of operation, compatibility with automated control systems, and adaptability to various climate environments. In contrast, the low-voltage auxiliary battery primarily provides stable power to the vehicle's control units, lighting systems, and various electronic devices. Its energy supply typically relies on an auxiliary power module (APM) to obtain power from the high-voltage power battery. This module generally employs an isolated DC-DC conversion topology.

[0004] The current APM system's technical architecture has significant limitations: it requires a separate isolated DC-DC circuit and a dedicated transformer to achieve high-voltage to low-voltage energy conversion. This independent design not only increases the overall weight and space occupancy of electric vehicles but also leads to high manufacturing and maintenance costs. It is noteworthy that the WPT system and APM share many structural commonalities in their power conversion links. Both include core components such as compensation networks, coupling coils, and AC-DC converters. This structural similarity provides a feasible basis for system integration.

[0005] For the integration of dual-battery charging system units in electric vehicles, existing research generally divides the integration of dual-battery charging systems into different levels, including mechanical integration at the structural level, topological integration at the circuit level, and magnetic integration at the magnetic component level. Among them, mechanical integration mainly improves system compactness through structural and packaging optimization; while topological and magnetic integration further achieve a higher degree of functional integration and energy sharing at the electrical level, and are considered to be the future development direction of highly integrated charging systems. Existing research on topological and magnetic integration explores the integrated design of on-board chargers (OBC) and APMs to achieve cost reduction and efficiency improvement, but research on the integration of on-board chargers (WPT) and APMs is still in its early stages.

[0006] Currently, the integration methods for WPT and APM all involve reusing the power electronic converter on the power battery side and eliminating the need for a transformer. However, the control methods for mode switching mainly fall into categories such as adding additional switches, frequency conversion, and designing specific coupling mechanisms. Existing literature adds an additional switch to the compensation network on the high-voltage battery side, and achieves the conversion between WPT and APM charging modes by opening and closing the switch. Although this enables simultaneous charging of high-voltage and low-voltage batteries, the use of a switch to configure the circuit for charging HV or LV batteries results in low system reliability. In addition, some existing literature combines the coupling coil and reverse winding of the APM, so that the LV-side coupling mechanism is decoupled from the transmitting coil but still meets the requirements for coupling with the HV-side coil. This can meet the requirements of two charging modes without additional components, but this method makes the design of the coupling mechanism more complex. Literature 7 integrates the independent charging structures of WPT, OBC, and APM. Although the system can operate in five charging modes, the conversion of charging modes still requires an additional switch.

[0007] In summary, while existing WPT and APM integration solutions can achieve good integration of roadside systems at the topology level and fusion at the magnetic component level, they are limited by the space constraints of electric vehicle on-board charging circuits, and their circuit structure still has component redundancy, especially during the charging mode switching process, some power devices are not fully utilized. Summary of the Invention

[0008] This invention addresses the problem that most existing wireless charging systems for electric vehicles only support charging the power battery, while the auxiliary battery relies on an independent onboard DC-DC converter for charging. The independent charging modes result in circuit topology redundancy. Therefore, this invention proposes a wireless charging system and method based on the integration of compact WPT and APM circuit topologies.

[0009] The technical solution adopted by the present invention to solve the above problems is: the wireless charging system based on the integration of compact WPT and APM circuit topology proposed in the present invention includes: The system includes a ground-side transmitter, a power battery receiver, and an auxiliary battery receiver. The ground-side transmitter is equipped with a ground-side transmitting coil.L p The power battery side receiver is equipped with a power battery side receiving coil. L s Ground-side transmitting coil L p and the receiving coil on the power battery side L s The two are coupled by a magnetic field, and the auxiliary battery side receiver is equipped with an auxiliary battery side coil. L r Auxiliary battery side coil L r Separately with the receiving coil on the power battery side L s Ground-side transmitting coil L p They are coupled through a magnetic field.

[0010] Furthermore, the ground-side transmitter includes power supply voltage. Filter capacitor C in Switching transistor Q 1. Switching transistor Q 2. Switching transistor Q 3. Switching transistor Q 4. Inductance Compensating inductance and capacitance of transmitting coil Compensating inductance and capacitance of transmitting coil C p and ground-side transmitting coil L p ; inductance Compensating inductance and capacitance of transmitting coil Compensating inductance and capacitance of transmitting coil C p To form an LCC compensation network, the switching transistors Q 1. Switching transistor Q 2. Switching transistor Q 3 and switching transistors Q 4 components form a full-bridge inverter circuit, with a power supply voltage of [voltage value missing]. The positive terminal is connected to the filter capacitor. C in positive terminal, switching transistor Q 1's drain and switching transistor Q 2's drain, power supply voltage The negative terminal is connected to the filter capacitor. C in negative terminal, switching transistor Q 1's source and switch Q 2's source; switch transistor Q 1's source is connected to the switching transistor. QThe drain of transistor 3 forms the input terminal of the full-bridge inverter circuit in the connection circuit; the switching transistor... Q 2. Source connection to the switching transistor Q The drain of 4 is connected to form the output terminal of the full-bridge inverter circuit in the connection circuit; The input terminal of the full-bridge inverter circuit is connected to an inductor. One end of the inductor The other end is connected to the transmitting coil compensation inductor and capacitor. The positive terminal and the compensating inductor and capacitor of the transmitting coil C p The positive terminal of the transmitting coil is the compensating inductor and capacitor. C p The negative terminal and the ground-side transmitting coil L p The input terminal is connected to the ground-side transmitting coil. L p The output terminal and the transmitting coil compensation inductor and capacitor The negative terminal connection.

[0011] Furthermore, the power battery receiver includes a power battery-side receiving coil. L s , power battery receiving coil compensation capacitor C s Switching transistor Q 5. Switching transistor Q 6. Switching transistor Q 7. Switching transistor Q 8. Filter capacitor C o and load R L1 ; Switching transistor Q 5. Switching transistor Q 6. Switching transistor Q 7 and switching transistor Q Eight components form a full-bridge controllable rectifier circuit, with the power battery side receiving coil. L s The receiving end is connected to the power battery receiving coil compensation capacitor. C s The positive terminal, the receiving coil on the power battery side. L s The output terminal is connected to the rectifier input terminal 1 of the full-bridge controlled rectifier circuit, and the power battery receiving coil compensation capacitor. C s The negative terminal is connected to the rectifier input terminal 2 of the full-bridge controlled rectifier circuit; Switching transistor Q 5's source and switch Q The drain of transistor 7 is connected, and a rectifier input terminal 2 is provided in the connection circuit; the switching transistor... Q5's drain and switching transistor Q 6 drain and filter capacitor C o Positive terminal connection, switching transistor Q 6's source and switch Q 8 drain connection, switching transistor Q 7's source and switch Q 8 source capacitors and filter capacitors C o Negative connection, filter capacitor C o Positive connection to load R L1 One end, filter capacitor C o Negative connection load R L1 The other end.

[0012] Furthermore, the auxiliary battery receiver includes an auxiliary battery side coil. L r Compensation capacitor C r Switching transistor Q I Freewheeling diode D I and load R L2 ; Auxiliary battery side coil L r The receiving end is connected to a compensation capacitor. C r The positive terminal and the output terminal are connected to the switching transistor. Q I Drain; compensation capacitor C r The negative terminals are respectively connected to the freewheeling diode. D I One end, switching transistor Q I The source, the switch Q I Drain connection load R L2 One end, freewheeling diode D I The other end is connected to the load. R L2 The other end.

[0013] Wireless charging methods based on the integration of compact WPT and APM circuit topologies include: The location of the electric vehicle is determined. When the electric vehicle is located in the area of ​​the ground-side transmitter, the wireless charging system enters WPT mode. The ground-side transmitter charges the power battery, and the switch Q1 is turned on. The auxiliary battery receiver is used as a relay layer. The soft switching of the switching device is achieved by rectifying and phase-shifting the input DC power to stably charge the power battery. Once the electric vehicle leaves the ground-side transmitter area, the wireless charging system switches from WPT mode to APM mode, using the power battery receiver as the transmitter to transfer energy to the auxiliary battery receiver and adjust the switching transistor. Q I The duty cycle of the PWM signal controls the load. R L2 The charging current and voltage are used to rectify the alternating current into direct current to charge the auxiliary battery. The charging current and voltage are dynamically adjusted according to the charging status of the power battery and auxiliary battery until charging is complete.

[0014] Furthermore, in WPT mode, the DC power from the ground-side transmitter is input into the full-bridge inverter circuit, and the switching transistors are controlled... Q 1-Switching transistor Q The conduction sequence of 4 converts direct current into alternating current. u ac and alternating current i f Alternating current i f Entering the LCC compensation network causes the ground-side transmitter to enter a resonant state, and the signal is transmitted through the ground-side transmitting coil. L p The alternating current is transmitted to the receiving end on the auxiliary battery side; Control switch tube Q I Conduction is achieved through the compensation capacitor. C r This allows the auxiliary battery-side receiver to enter the relay model, via the auxiliary battery-side coil. L r and ground-side transmitting coil L p Mutual intuition between Receiver ground side transmitting coil L p The emitted alternating current passes through the auxiliary battery side coil. L r and the receiving coil on the power battery side L s Mutual intuition between The received alternating current is relayed to the receiving coil on the power battery side. L s ; Power battery side receiving coilL s After receiving alternating current, the energy is transferred through the power battery receiving coil and compensation capacitor. C s The input is a full-bridge controlled rectifier circuit, which controls the switching transistors. Q 5-Switching transistor Q An 8-phase-shift angle converts alternating current into direct current, providing stable charging for the power battery.

[0015] Furthermore, in APM mode, the full-bridge controllable rectifier circuit is switched to inverter mode to convert the DC power stored in the power battery into AC power, and the power battery side receiving coil... L s As a transmitting coil, through mutual inductance AC power is transferred to the auxiliary battery side coil. L r Through the freewheeling diode D I The alternating current is rectified into direct current by adjusting the switching transistor. Q I The PWM signal duty cycle is adjusted to step down the DC power supply based on the charging requirements of the auxiliary battery, thereby enabling precise charging of the auxiliary battery.

[0016] The beneficial effects of this invention are: 1. This invention significantly reduces the overall weight and volume of the electric vehicle charging system by topologically integrating the WPT and APM, thereby lowering system manufacturing and installation costs and improving structural compactness and space utilization. This integrated solution reduces multi-stage power processing steps through the shared design of the power conversion unit and magnetic components, thus reducing energy transmission losses and improving system operating efficiency.

[0017] 2. In WPT mode, when the ground-side transmitter is charging the power battery, the auxiliary power circuit can use its own characteristics to convert its coil into a relay layer, thus avoiding the disturbance problem of energy transfer in three coils.

[0018] 3. In APM mode, the auxiliary battery circuit topology uses an IRPA circuit to continue charging, using only one diode, one switching transistor and a filter capacitor, which maximizes the compactness and lightweight of the secondary circuit topology. This topology has high space utilization efficiency and is therefore particularly suitable for wireless charging applications with limited space, such as auxiliary batteries for electric vehicles.

[0019] 4. The integrated design of WPT and APM enables the wireless charging system to flexibly switch between wireless charging mode and auxiliary power supply mode according to different operating scenarios, achieving coordinated management of the power battery and auxiliary battery, further enhancing system stability and vehicle range performance. Furthermore, the auxiliary battery side circuit topology adopts an IRPA circuit, whose power devices use only one switching transistor and one diode, minimizing the number of switching devices compared to traditional circuit topologies, further reducing costs and improving overall energy transfer efficiency. This efficient charging method suitable for dual batteries in electric vehicles provides a new solution for the intelligent upgrading and reliability improvement of electric vehicle energy systems. Attached Figure Description

[0020] Figure 1 Circuit diagram of a wireless charging system based on a compact WPT and APM circuit topology integration; Figure 2 The circuit diagram of a wireless charging system in WPT mode; Figure 3 Circuit diagram of a wireless charging system in APM mode; Figure 4 A simplified circuit diagram for WPT mode; Figure 5 The circuit diagram shows a wireless charging system based on the secondary-side IRPA circuit topology in APM mode. Figure 6 A schematic diagram of the working modes of a wireless charging system in APM mode; Figure 7 A schematic diagram of a wireless charging method based on the integration of compact WPT and APM circuit topology; Figure 8 Simulation circuit diagram for a wireless charging system; Figure 9 Output voltage and current waveforms for different equivalent load resistances; Figure 10 A schematic diagram showing the phase relationship between the inverter output voltage and current at the ground-side transmitter. Figure 11 The output characteristics of the power battery under an equivalent load of 30Ω and different phase shift angles are shown in the figure. Figure 12 The output voltage and current waveforms of the auxiliary battery with different equivalent load resistances; Figure 13 A schematic diagram of the simulation results between Io2 and D for different equivalent load resistances; Figure 14 A schematic diagram of the simulation results for constant current charging; Figure 15 A schematic diagram of the simulation results for constant voltage charging; Figure 16This is a schematic diagram showing the phase relationship between the inverter output voltage and current at the transmitter side of the power battery. Detailed Implementation

[0021] Specific implementation method one: as follows Figure 1 As shown, the structure of the wireless charging system based on the compact WPT and APM circuit topology integration described in this embodiment includes: The system consists of a ground-side transmitter, a power battery receiver, and an auxiliary battery receiver. The power battery receiver circuit topology uses a full-bridge controlled rectifier, while the auxiliary battery receiver uses an IRPA circuit, which achieves rectification and buck conversion using only two power devices. The system has two operating modes: 1. In wireless power transfer mode, the ground-side transmitter charges the power battery, and this is achieved by controlling the switching transistor at the auxiliary battery terminal. First, by activating the auxiliary battery coil, the charging process can be streamlined to avoid the impact of auxiliary power supply resistance variations on the charging of the main battery. Second, in auxiliary power supply management mode, the main battery acts as the transmitter to charge the auxiliary battery (note: at this time, the electric vehicle has left the ground-side transmitter). The auxiliary battery side utilizes an IRPA circuit, which, compared to the traditional rectifier bridge + buck circuit, significantly reduces the number of power devices required, achieving constant current and constant voltage output for the wireless charging system and ensuring a compact and lightweight secondary circuit topology. This system integrates WPT and APM charging modes to achieve a shared circuit topology on the main battery side, eliminating the APM transformer, reducing costs, and improving light-load efficiency and overall energy transfer efficiency, making it suitable for efficient charging of dual batteries in electric vehicles.

[0022] The ground-side transmitter includes the power supply voltage. Filter capacitor C in Switching transistor Q 1. Switching transistor Q 2. Switching transistor Q 3. Switching transistor Q 4. Inductance Compensating inductance and capacitance of transmitting coil Compensating inductance and capacitance of transmitting coil C p and ground-side transmitting coil L p ;inductance Compensating inductance and capacitance of transmitting coil Compensating inductance and capacitance of transmitting coil C p To form an LCC compensation network, the switching transistors Q 1. Switching transistor Q 2. Switching transistor Q 3 and switching transistors Q 4 components form a full-bridge inverter circuit, with a power supply voltage of [voltage value missing]. The positive terminal is connected to the filter capacitor.C in positive terminal, switching transistor Q 1's drain and switching transistor Q 2's drain, power supply voltage The negative terminal is connected to the filter capacitor. C in negative terminal, switching transistor Q 1's source and switch Q 2's source; switch transistor Q 1's source is connected to the switching transistor. Q The drain of transistor 3 forms the input terminal of the full-bridge inverter circuit in the connection circuit; the switching transistor... Q 2. Source connection to the switching transistor Q The drain of the 4-pin inductor forms the output of the full-bridge inverter circuit in the connection circuit; the input of the full-bridge inverter circuit is connected to the inductor. One end of the inductor The other end is connected to the transmitting coil compensation inductor and capacitor. The positive terminal and the compensating inductor and capacitor of the transmitting coil C p The positive terminal of the transmitting coil is the compensating inductor and capacitor. C p The negative terminal and the ground-side transmitting coil L p The input terminal is connected to the ground-side transmitting coil. L p The output terminal and the transmitting coil compensation inductor and capacitor The negative terminal connection.

[0023] The power battery receiver includes a power battery-side receiving coil. L s , power battery receiving coil compensation capacitor C s Switching transistor Q 5. Switching transistor Q 6. Switching transistor Q 7. Switching transistor Q 8. Filter capacitor C o ,load R L1 Switching transistor Q 5. Switching transistor Q 6. Switching transistor Q 7 and switching transistor Q Eight components form a full-bridge controllable rectifier circuit, with the power battery side receiving coil. L s The receiving end is connected to the power battery receiving coil compensation capacitor. C s The positive terminal, the receiving coil on the power battery side. L sThe output terminal is connected to the rectifier input terminal 1 of the full-bridge controlled rectifier circuit, and the power battery receiving coil compensation capacitor. C s The negative terminal is connected to the rectifier input terminal 2 of the full-bridge controlled rectifier circuit; the switching transistor Q 5's source and switch Q The drain of transistor 7 is connected, and a rectifier input terminal 2 is provided in the connection circuit; the switching transistor... Q 5's drain and switching transistor Q 6 drain and filter capacitor C o Positive terminal connection, switching transistor Q 6's source and switch Q 8 drain connection, switching transistor Q 7's source and switch Q 8 source capacitors and filter capacitors C o Negative connection, filter capacitor C o Positive connection to load R L1 One end, filter capacitor C o Negative connection load R L1 The other end.

[0024] The auxiliary battery receiver includes an auxiliary battery side coil. L r Compensation capacitor C r Switching transistor Q I Freewheeling diode D I and load R L2 Auxiliary battery side coil L r The receiving end is connected to a compensation capacitor. C r The positive terminal and the output terminal are connected to the switching transistor. Q I Drain; compensation capacitor C r The negative terminals are respectively connected to the freewheeling diode. D I One end, switching transistor Q I The source, the switch Q I Drain connection load R L2 One end, freewheeling diode D I The other end is connected to the load. RL2 The other end.

[0025] This invention significantly reduces the overall weight and size of the electric vehicle charging system by topologically integrating the WPT and APM, thereby lowering system manufacturing and installation costs and improving structural compactness and space utilization. This integrated solution reduces multi-stage power processing steps through the shared design of the power conversion unit and magnetic components, thus reducing energy transmission losses and improving system operating efficiency.

[0026] Specific implementation method two: such as Figure 7 As shown, the steps of the wireless charging method based on the integration of compact WPT and APM circuit topology described in this embodiment include: S1: Determine the location of the electric vehicle. When the electric vehicle is located in the ground-side transmitter area, the wireless charging system enters WPT mode to stably charge the power battery. Circuit topology in WPT mode is as follows Figure 2 As shown, the DC power from the ground-side transmitter is input into the full-bridge inverter circuit, and controlled by the switching transistors... Q 1-Switching transistor Q The conduction sequence of 4 converts direct current into alternating current. u ac and alternating current i f To simplify the analysis, the internal resistance of the coil, inductor, and capacitor is ignored in this embodiment, and the alternating current is... i f Entering the LCC compensation network causes the ground-side transmitter to enter a resonant state, and the signal is transmitted through the ground-side transmitting coil. L p The alternating current is transmitted to the receiving end on the auxiliary battery side; Control switch tube Q I Conduction is achieved through the compensation capacitor. C r This allows the auxiliary battery-side receiver to enter the relay model, via the auxiliary battery-side coil. L r and ground-side transmitting coil L p Mutual intuition between Receiver ground side transmitting coil L p The emitted alternating current passes through the auxiliary battery side coil. L r and the receiving coil on the power battery side L s Mutual intuition between The received alternating current is relayed to the receiving coil on the power battery side. L s Power battery side receiving coilL s After receiving alternating current, the energy is transferred through the power battery receiving coil and compensation capacitor. C s The input is a full-bridge controlled rectifier circuit, which controls the switching transistors. Q 5-Switching transistor Q An 8-phase-shift angle converts alternating current into direct current, providing stable charging for the power battery.

[0027] Because the power side coil and the auxiliary power supply side coil are arranged closely vertically, and None of these factors can be ignored. By using the auxiliary battery side only for the relay layer, the problem of mutual interference in the transmitted energy of a single-transmitter, dual-receiver, three-coil wireless charging system can be avoided. Note: In this case, the IRPA circuit (auxiliary power supply side circuit topology) It is in the conducting state to achieve the effect of a relay coil. A simplified system circuit diagram is shown below. Figure 4 As shown.

[0028] The impedances of each part of the system are defined as follows: (1); In formula (1), The imaginary unit, ω is the angular frequency.

[0029] From KVL, we can obtain: (2); (3); (4); (5); Combining formulas (3) and (4), we can obtain: (6); There is no such expression in this equation. The parameters are such that the output current of the power battery is independent of the load.

[0030] From (3), we can know that:

[0031] Because the transmitter, the power battery, and the relay coil are all in a resonant state, but The load Req is the equivalent load of the controllable rectification and subsequent circuits.

[0032] By simplification, we get: (7); because All are resistive, meaning the numerator is purely resistive; the denominator is a complex number, which can be adjusted appropriately. This can make It can be purely resistive or slightly inductive. This is used to implement ZPA (Zero-Pulse Switching) to achieve soft switching of switching devices, reducing device losses, improving efficiency, and enhancing system stability.

[0033] In WPT mode, when the ground-side transmitter is charging the power battery, the auxiliary power circuit can use its own characteristics to convert its coil into a relay layer, thus avoiding the disturbance problem of energy transfer in three coils.

[0034] S2: When the electric vehicle leaves the ground-side transmitter area, the wireless charging system switches from WPT mode to APM mode to charge the auxiliary battery; Circuit topology in APM mode as follows Figure 3 As shown, the power battery side adopts a controllable full-bridge circuit. After the electric vehicle leaves the ground-side transmitter area, in APM mode... All are zero. The full-bridge controllable rectifier circuit is switched to inverter mode to convert the DC power stored in the power battery into AC power, and the power battery side receiving coil... L s As a transmitting coil, it transmits alternating current to the auxiliary battery side coil through mutual inductance. L r Through the freewheeling diode D I The alternating current is rectified into direct current by adjusting the switching transistor. Q I The PWM signal duty cycle is adjusted to step down the DC power supply based on the charging requirements of the auxiliary battery, thereby enabling precise charging of the auxiliary battery.

[0035] By changing ~ The control strategy involves transferring energy from the power battery to the auxiliary power supply side. Simultaneously, the auxiliary power supply side circuit topology employs an IRPA circuit. The IRPA not only rectifies the alternating current in the secondary resonant coil into direct current, but also adjusts Q... II The duty cycle of the PWM signal further controls the charging current and voltage of the load.

[0036] according to Figure 5 The circuit topology shown and Figure 6 The operating waveforms shown are used to analyze the operating modes of the wireless charging system based on the secondary-side IRPA circuit topology. [1]. The first stage, corresponding to Figure 6 Middle I. Q I The PWM drive signal is low. Q I When in an open-circuit state, the secondary resonant coil current... In the negative half-cycle, Inflow filter capacitor After being loaded, it returns to the secondary resonant coil.

[0037] [2]. The second stage corresponds to Figure 6 Middle II. Q I The PWM drive signal is low. Q I When in an open-circuit state, the secondary resonant coil current... In the positive half-cycle, Flowing Q I1 The current flows back to the secondary resonant coil after passing through the freewheeling diode, but does not flow into the filter capacitor. and load.

[0038] [3]. The third stage, corresponding to Figure 6 Middle III. Q I The PWM drive signal is high level. Q I When in a closed circuit state, the secondary resonant coil current... In the positive half-cycle, Flowing Q I1 The current flows back to the secondary resonant coil after passing through the freewheeling diode, but does not flow into the filter capacitor. and load.

[0039] [4]. The fourth stage, corresponding to Figure 6 IV. Q I The PWM drive signal is high level. Q I When in a closed state, the secondary resonant coil current... During the negative half-cycle, a portion of the current... Inflow Q I Then it returns to the secondary resonant coil, and another part of the current... Inflow filter capacitor After being loaded, it returns to the secondary resonant coil.

[0040] In summary, in the entire IRPA workflow, the duty cycle of the PWM signal in the fourth stage is... D (The value range is 0~1) is the core element for adjusting the charging current and voltage.

[0041] Combination Figure 5 and Figure 6 Obtain charging current I o2 Duty cycle of PWM signal DThe relationship between them. Assuming the secondary coil resonant current... i s The expression is: (8); Combination Figure 7 Working modes in I o2 and I s The expression between them is (9). According to... Figure 7 The waveform can be further used to derive the expression (10) that T1 and T satisfy: (9); (10); Combining formulas (9) and (10), we can obtain I o2 and D The expression between them is (11). Clearly, control... D Further adjustments are possible. I o2 or U o2 .

[0042] (11); In APM mode, the auxiliary battery circuit topology uses an IRPA circuit to continue charging, using only one diode, one switching transistor and a filter capacitor, which maximizes the compactness and lightweight of the secondary circuit topology. This topology has high space utilization efficiency and is therefore particularly suitable for wireless charging applications with limited space, such as auxiliary batteries for electric vehicles.

[0043] S3: Dynamically adjusts the charging current and voltage based on the charging status of the power battery and auxiliary battery until charging is complete.

[0044] In summary, the integrated design of WPT and APM enables the wireless charging system to flexibly switch between wireless charging mode and auxiliary power supply mode according to different operating scenarios, achieving coordinated management of the power battery and auxiliary battery, and further enhancing system stability and vehicle range performance. Furthermore, the auxiliary battery side circuit topology adopts an IRPA circuit, whose power devices use only one switching transistor and one diode, minimizing the number of switching devices compared to traditional circuit topologies, further reducing costs and improving overall energy transfer efficiency. This efficient charging method suitable for dual batteries in electric vehicles provides a new solution for the intelligent upgrading and reliability improvement of electric vehicle energy systems.

[0045] To verify the technical effects of the present invention, the following tests were conducted in this embodiment: Simulation circuit of wireless charging system, such as Figure 8 As shown, the core parameters are as follows: DC bus voltage is 150V, the self-inductance of the primary coil on the ground side of the coupling mechanism is 110μH, the self-inductance of the power battery side coil is 85μH, and the self-inductance of the auxiliary battery side coil (relay coil) is 60μH. The mutual inductance relationship is as follows: During charging, the equivalent load resistance of the power battery varies from 30Ω to 42Ω, while the equivalent load resistance of the auxiliary battery varies from 5Ω to 11Ω. It should be noted that because APM mode operates after the electric vehicle leaves the ground-side transmitter area, the APM mode... All values ​​are zero. It is important to note that the simulation data used here is for illustrative purposes only; the method proposed in this invention is also applicable to other parameter requirements.

[0046] (1) Simulation results of WPT mode; Combination Figure 8 Given the parameters, under open-loop operation of the system, such as Figure 9 The output voltage and current waveforms with different equivalent load resistances clearly demonstrate that the circuit topology can achieve a charging current that is essentially independent of the load.

[0047] The phase relationship between the inverter output voltage and current at the ground-side transmitter is as follows: Figure 10 Obviously, by designing a suitable , , and The value of makes the primary side exhibit a slightly detuned state, under which ZVS can be achieved to reduce device losses, improve efficiency and system stability.

[0048] Simulation results show that by controlling the phase shift angle (0°-180°) of the full-bridge controllable rectifier, the charging current and voltage of the power battery can be effectively adjusted. Figure 11 Specifically, it demonstrates the power battery output characteristics corresponding to this control strategy under an equivalent load of 30Ω.

[0049] (2) Simulation results of APM mode; a) Open-loop charging; Combination Figure 8 Given the parameters, the output voltage and current waveforms of the auxiliary battery with different equivalent load resistances under open-loop system operation are as follows: Figure 12 As shown, the simulation results clearly verify that the circuit topology can achieve constant current charging.

[0050] Combination Figure 8 Given the parameters, the system operates in open loop with different equivalent load resistances. I o2 and D The simulation results between are plotted on Figure 13 In summary, the simulation results clearly verify the control... D Adjustable I o2 or U o2 Furthermore, simulation results further verify that even without closed-loop control, D Fixed value I o2 Its size is basically independent of the load.

[0051] b) Constant current charging Taking a charging current of 3A as an example, the equivalent load resistance varies from 5Ω to 11Ω with a step size of 2Ω. The simulation results are shown below. Figure 14 Obviously, regulation Q I PWM signal duty cycle D It can achieve stable constant current charging.

[0052] c) Constant voltage charging Taking a charging voltage of 12V as an example, the equivalent load resistance varies from 5Ω to 11Ω, with a step size of 2Ω. The simulation results are shown below. Figure 15 Obviously, regulation Q I PWM signal duty cycle D It can achieve stable constant voltage charging.

[0053] The phase relationship between the inverter output voltage and current on the power battery side transmitter is as follows: Figure 16 Clearly, ZVS can be achieved in this mode to reduce device losses, improve efficiency, and enhance system stability.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A wireless charging system based on a compact WPT and APM circuit topology integration, characterized in that, include: The system includes a ground-side transmitter, a power battery receiver, and an auxiliary battery receiver. The ground-side transmitter is equipped with a ground-side transmitting coil. L p The power battery side receiver is equipped with a power battery side receiving coil. L s Ground-side transmitting coil L p and the receiving coil on the power battery side L s The two are coupled by a magnetic field, and the auxiliary battery side receiver is equipped with an auxiliary battery side coil. L r Auxiliary battery side coil L r Separately with the receiving coil on the power battery side L s Ground-side transmitting coil L p They are coupled through a magnetic field.

2. The wireless charging system based on the compact WPT and APM circuit topology integration according to claim 1, characterized in that, The ground-side transmitter includes a power supply voltage. Filter capacitor C in Switching transistor Q 1. Switching transistor Q 2. Switching transistor Q 3. Switching transistor Q 4. Inductance Compensating inductance and capacitance of transmitting coil Compensating inductance and capacitance of transmitting coil C p and ground-side transmitting coil L p ; inductance Compensating inductance and capacitance of transmitting coil Compensating inductance and capacitance of transmitting coil C p To form an LCC compensation network, the switching transistors Q 1. Switching transistor Q 2. Switching transistor Q 3 and switching transistors Q 4 components form a full-bridge inverter circuit, with a power supply voltage of [voltage value missing]. The positive terminal is connected to the filter capacitor. C in positive terminal, switching transistor Q 1's drain and switching transistor Q 2's drain, power supply voltage The negative terminal is connected to the filter capacitor. C in negative terminal, switching transistor Q 1's source and switch Q 2's source; switch transistor Q 1's source is connected to the switching transistor. Q The drain of transistor 3 forms the input terminal of the full-bridge inverter circuit in the connection circuit; the switching transistor... Q 2. Source connection to the switching transistor Q The drain of 4 is connected to form the output terminal of the full-bridge inverter circuit in the connection circuit; The input terminal of the full-bridge inverter circuit is connected to an inductor. One end, inductor The other end is connected to the transmitting coil compensation inductor and capacitor. The positive terminal and the compensating inductor and capacitor of the transmitting coil C p The positive terminal of the transmitting coil is the compensating inductor and capacitor. C p The negative terminal and the ground-side transmitting coil L p The input terminal is connected to the ground-side transmitting coil. L p The output terminal and the transmitting coil compensation inductor and capacitor The negative terminal connection.

3. The wireless charging system based on the integration of compact WPT and APM circuit topology according to claim 1, characterized in that, The power battery receiver includes a power battery-side receiving coil. L s , power battery receiving coil compensation capacitor C s Switching transistor Q 5. Switching transistor Q 6. Switching transistor Q 7. Switching transistor Q 8. Filter capacitor C o and load R L1 ; Switching transistor Q 5. Switching transistor Q 6. Switching transistor Q 7 and switching transistor Q Eight components form a full-bridge controllable rectifier circuit, with the power battery side receiving coil. L s The receiving end is connected to the power battery receiving coil compensation capacitor. C s The positive terminal, the receiving coil on the power battery side. L s The output terminal is connected to the rectifier input terminal 1 of the full-bridge controlled rectifier circuit, and the power battery receiving coil compensation capacitor. C s The negative terminal is connected to the rectifier input terminal 2 of the full-bridge controlled rectifier circuit; Switching transistor Q 5's source and switch Q The drain of transistor 7 is connected, and a rectifier input terminal 2 is provided in the connection circuit; the switching transistor... Q 5's drain and switching transistor Q 6 drain and filter capacitor C o Positive terminal connection, switching transistor Q 6's source and switch Q 8 drain connection, switching transistor Q 7's source and switch Q 8 source capacitors and filter capacitors C o Negative connection, filter capacitor C o Positive connection to load R L1 One end, filter capacitor C o Negative connection load R L1 The other end.

4. The wireless charging system based on the integration of compact WPT and APM circuit topology according to claim 1, characterized in that, The auxiliary battery receiver includes an auxiliary battery side coil. L r Compensation capacitor C r Switching transistor Q I Freewheeling diode D I and load R L2 ; Auxiliary battery side coil L r The receiving end is connected to a compensation capacitor. C r The positive terminal and the output terminal are connected to the switching transistor. Q I Drain; compensation capacitor C r The negative terminals are respectively connected to the freewheeling diode. D I One end, switching transistor Q I The source, the switch Q I Drain connection load R L2 One end, freewheeling diode D I The other end is connected to the load. R L2 The other end.

5. A wireless charging method based on the integration of compact WPT and APM circuit topologies, applied to the wireless charging system based on the integration of compact WPT and APM circuit topologies as described in any one of claims 1-4, characterized in that, include: The location of the electric vehicle is determined. When the electric vehicle is located in the area of ​​the ground-side transmitter, the wireless charging system enters WPT mode. The ground-side transmitter charges the power battery, and the switch Q1 is turned on. The auxiliary battery receiver is used as a relay layer. The soft switching of the switching device is achieved by rectifying and phase-shifting the input DC power to stably charge the power battery. Once the electric vehicle leaves the ground-side transmitter area, the wireless charging system switches from WPT mode to APM mode, using the power battery receiver as the transmitter to transfer energy to the auxiliary battery receiver and adjust the switching transistor. Q I The duty cycle of the PWM signal controls the load. R L2 The charging current and voltage are used to rectify the alternating current into direct current to charge the auxiliary battery. The charging current and voltage are dynamically adjusted according to the charging status of the power battery and auxiliary battery until charging is complete.

6. The wireless charging method based on the integration of compact WPT and APM circuit topology according to claim 5, characterized in that, In WPT mode, the DC power from the ground-side transmitter is input into the full-bridge inverter circuit, and the switching transistors are controlled. Q 1-Switching transistor Q The conduction sequence of 4 converts direct current into alternating current. u ac and alternating current i f Alternating current i f Entering the LCC compensation network causes the ground-side transmitter to enter a resonant state, which is then transmitted through the ground-side transmitting coil. L p The alternating current is transmitted to the receiving end on the auxiliary battery side; Control switch tube Q I Conduction is achieved through the compensation capacitor. C r This allows the auxiliary battery-side receiver to enter the relay model, via the auxiliary battery-side coil. L r and ground-side transmitting coil L p Mutual intuition between Receiver ground side transmitting coil L p The emitted alternating current passes through the auxiliary battery side coil. L r and the receiving coil on the power battery side L s Mutual intuition between The received alternating current is relayed to the receiving coil on the power battery side. L s ; Power battery side receiving coil L s After receiving alternating current, the energy is transferred through the power battery receiving coil and compensation capacitor. C s The input is a full-bridge controlled rectifier circuit, which controls the switching transistors. Q 5-Switching transistor Q An 8-phase-shift angle converts alternating current into direct current, providing stable charging for the power battery.

7. The wireless charging method based on the integration of compact WPT and APM circuit topology according to claim 5, characterized in that, In APM mode, the full-bridge controlled rectifier circuit is switched to inverter mode to convert the DC power stored in the power battery into AC power, and the power battery side receiving coil... L s As a transmitting coil, through mutual inductance AC power is transferred to the auxiliary battery side coil. L r Through the freewheeling diode D I The alternating current is rectified into direct current by adjusting the switching transistor. Q I The PWM signal duty cycle is adjusted to step down the DC power supply based on the charging requirements of the auxiliary battery, thereby enabling precise charging of the auxiliary battery.

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