Single lithium battery exchange light double input charging control method and device and medium

Abstract

The present application relates to a kind of for single lithium battery exchange light double-input charging control method, device and medium, wherein, by detecting the electrical state of alternating current side and photovoltaic side port to determine the working mode, accordingly control corresponding front-stage power circuit alternating current or mixed working mode enable active power factor correction circuit, photovoltaic mode enable photovoltaic maximum power point tracking boost circuit, the output direct current of both is converged to common high-voltage direct current bus;Control bus and the only fixed-frequency resonant type TAB converter between battery works in fixed resonant frequency state, utilize its built-in high-frequency transformer isolation conversion and battery low-voltage side diode rectification clamping processing after output adaptation electric energy;Through the power regulation of front-stage circuit, realize constant-current or constant-voltage charging closed loop.By three-way port architecture and converter multiplexing design, adaptation double-input extreme scene, efficiently solve single lithium battery exchange light double-input charging problem.

Description

Technical Field

[0001] This invention relates to the technical field of new energy storage, and in particular to a method, device and medium for controlling dual-input charging of a single lithium battery with alternating light and electricity. Background Technology

[0002] With the widespread adoption of portable electronic devices, IoT terminals, and light power tools, single-cell lithium batteries have become the core energy storage unit due to their high energy density and small size. Meanwhile, the demand for green charging with dual inputs of AC mains power and solar photovoltaic power is becoming increasingly urgent, placing stringent requirements on the efficiency, cost, size, and low-voltage high-current adaptability of charging systems.

[0003] Existing dual-input charging solutions have significant technical limitations. For the low-voltage characteristics of single-cell lithium batteries, traditional non-isolated BUCK / BOOST topologies suffer from increased switching losses due to the high voltage difference between the photovoltaic and battery, resulting in low conversion efficiency and failure to meet safety isolation requirements. If separate isolated charging circuits are configured for AC and photovoltaic components, such as traditional LLC or DAB converters, problems arise including system redundancy, high cost, and large size. Furthermore, traditional phase-shift controlled DAB converters are prone to short-circuit risks in low-leakage, low-voltage, high-current scenarios, while conventional LLC converters face difficulties in resonant parameter adaptation and high rectification losses, making it difficult to balance safety and efficiency in extreme scenarios. Therefore, there is an urgent need for an integrated dual-input charging solution adapted to single-cell lithium batteries that can meet the requirements of safety isolation and low-voltage, high-current transmission while simplifying the topology and reducing costs and losses. Summary of the Invention

[0004] The main objective of this invention is to provide a method, device, and medium for controlling dual-input charging of a single-cell lithium battery using optical switching. Through a three-port architecture and converter multiplexing design, it efficiently solves the problem of dual-input charging of a single-cell lithium battery using optical switching.

[0005] To achieve the above objectives, the present invention provides a method for controlling dual-input charging of a single lithium battery, comprising the following steps:

[0006] The electrical parameters of the AC side port, photovoltaic side port and battery low-voltage side port are detected to obtain the detection results. Based on the detection results, the current working mode is determined to be any one of AC charging mode, photovoltaic charging mode and hybrid charging mode.

[0007] If in the AC charging mode or hybrid charging mode, the active power factor correction circuit connected to the AC side port is controlled to work and convert the AC mains power into the first DC power; if in the photovoltaic charging mode, the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port is controlled to work and boost the photovoltaic DC power into the second DC power.

[0008] The first or second DC power is transmitted to a common high-voltage DC bus;

[0009] The preset fixed-frequency resonant TAB converter operates the high-voltage DC bus at a fixed resonant frequency, and the low-voltage side port of the battery is rectified by the high-frequency transformer built into the fixed-frequency resonant TAB converter to output electrical energy adapted to a single lithium battery.

[0010] The fixed-frequency resonant TAB converter is reused in each charging mode, and its operating frequency is fixed and does not use phase-shift control. The three-port architecture and the reuse design of the fixed-frequency resonant TAB converter are adapted to dual-input extreme application scenarios. The three-port architecture includes an AC side port, a photovoltaic side port and a battery low-voltage side port.

[0011] The output power is adjusted according to the voltage and current of the single lithium battery cell to perform constant current charging or constant voltage charging closed loop.

[0012] Furthermore, the step of controlling the preset fixed-frequency resonant TAB converter to operate the high-voltage DC bus at a fixed resonant frequency includes:

[0013] The fixed-frequency resonant TAB converter uses the transformer leakage inductance as the only resonant inductor, and together with the resonant capacitor, it forms an equivalent LC series resonant circuit. The equivalent LC series resonant circuit has a fixed resonant frequency. Furthermore, the magnetizing inductor in the fixed-frequency resonant TAB converter does not participate in the LC series resonance, but only provides a freewheeling path for the current during the dead time of the switching transistor drive.

[0014] The freewheeling path is used to stabilize the energy transmission of the high-voltage DC bus.

[0015] Furthermore, the step of using the transformer leakage inductance as the sole resonant inductor and combining it with the resonant capacitor to form an equivalent LC series resonant circuit in the fixed-frequency resonant TAB converter includes:

[0016] The active bridge switching transistors on the primary side of the fixed-frequency resonant TAB converter are controlled to conduct alternately at a fixed resonant frequency, converting the DC power on the high-voltage DC bus into high-frequency AC power. The high-frequency AC power is then excited into a resonant state through an LC series resonant network.

[0017] The high-frequency transformer is used to achieve high and low voltage electrical isolation and voltage level matching in a three-port architecture.

[0018] The diode rectifier structure at the low-voltage side port of the battery performs AC-DC conversion to limit voltage spikes in conjunction with the clamping circuit.

[0019] During the dead-time phase of the signal-bound switching transistor driven by the clamping circuit that limits voltage spikes, the magnetizing inductor provides a freewheeling path to assist the primary-side switching transistor in performing a soft-switching operation with zero voltage turn-on. At the same time, the diode is naturally turned off using the resonant current.

[0020] Furthermore, the step of fixing the resonant frequency of the equivalent LC series resonant circuit includes:

[0021] Based on the fixed-frequency resonant TAB converter, the resonant parameter matching relationship of the equivalent LC series resonant circuit is derived using the target value of the fixed resonant frequency, and the matching range of the transformer leakage inductance and the selection range of the resonant capacitor value are determined.

[0022] The actual leakage inductance value of the built-in high-frequency transformer of the fixed-frequency resonant TAB converter is detected. After eliminating measurement errors, a resonant capacitor matching the actual leakage inductance value is selected from the preset capacitance selection range.

[0023] The selected resonant capacitor is connected to the leakage inductance of the high-frequency transformer to form an equivalent LC series resonant circuit, so that the inherent resonant frequency of the circuit is consistent with the preset fixed resonant frequency target value.

[0024] Start the fixed-frequency resonant TAB converter, and collect the voltage and current signals of the equivalent LC series resonant circuit in real time. The circuit resonance state is determined by signal analysis.

[0025] If the inherent resonant frequency of the circuit is detected to deviate from the preset target value, compensation and calibration are performed by fine-tuning the capacitance value of the resonant capacitor until the circuit operates stably at the preset fixed resonant frequency.

[0026] Furthermore, the step of the magnetizing inductor in the fixed-frequency resonant TAB converter not participating in the LC series resonance, but only providing a freewheeling path for the current during the dead time of the switching transistor drive, includes:

[0027] The actual parameters of the magnetizing inductance of the built-in high-frequency transformer of the fixed-frequency resonant TAB converter are detected, and the range of the dead time of the switch drive is set based on the actual parameters to ensure that the dead time matches the energy storage characteristics of the magnetizing inductance.

[0028] Configure the freewheeling circuit of the magnetizing inductor so that the freewheeling circuit is turned on only during the dead time phase of the switch tube drive and turned off during the non-dead time phase, so as to avoid the magnetizing inductor participating in the resonance process of the equivalent LC series resonant circuit.

[0029] When the fixed-frequency resonant TAB converter is started, the freewheeling current waveform of the magnetizing inductor is monitored in real time during the dead zone of the switching transistor drive.

[0030] If the freewheeling current is detected to be interrupted or fluctuate beyond a preset threshold, the dead time parameter of the switch driver is adjusted to ensure that the freewheeling path is continuously and stably connected.

[0031] The resonance state of the equivalent LC series resonant circuit was monitored synchronously to verify that the freewheeling action of the magnetizing inductor did not interfere with the fixed resonant frequency of the resonant circuit.

[0032] Furthermore, the step of controlling the active power factor correction circuit connected to the AC side port to operate and convert AC mains power into first DC power when in AC charging mode or hybrid charging mode includes:

[0033] The active power factor correction circuit is activated and connected to a wide range of AC mains power on the AC side port.

[0034] The power factor correction adjustment logic is implemented to control the on / off timing of the full-bridge switching transistors in the active power factor correction circuit, so that the input current waveform tracks the input voltage waveform.

[0035] The voltage signal of the high-voltage DC bus is acquired, and the power factor correction regulation logic is dynamically adjusted according to the voltage signal to stabilize the power energy after power factor correction and output the first DC power to the high-voltage DC bus.

[0036] In the hybrid charging mode, the output status signal of the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port is synchronously acquired. Based on the output status signal and the high voltage DC bus voltage signal, the on / off timing of the full-bridge switching transistors and the output adjustment parameters of the active power factor correction circuit are synchronously adjusted.

[0037] Furthermore, the step of adjusting the output power according to the voltage and current of the single lithium battery to perform a constant current charging or constant voltage charging closed loop includes:

[0038] The constant current charging current target value, constant voltage charging voltage target value, and charging termination current threshold value are preset for the fixed frequency resonant TAB converter.

[0039] The voltage and current signals of the single lithium battery are collected in real time, and the current output power signals of the active power factor correction circuit connected to the AC side port and the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port are collected simultaneously. The active power factor correction circuit connected to the AC side port and the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port together constitute the front-end power circuit.

[0040] Compare the collected voltage signal of a single lithium battery cell with the preset constant voltage charging voltage target value: If the voltage value corresponding to the voltage signal of a single lithium battery cell is lower than the constant voltage charging voltage target value, execute constant current charging control, and adjust the output parameters of the front-end power circuit to stabilize the current value corresponding to the charging current signal of a single lithium battery cell at the preset constant current charging current target value.

[0041] When the voltage value corresponding to the voltage signal of a single lithium battery reaches or exceeds the preset constant voltage charging voltage target value, the system switches to constant voltage charging control. By adjusting the output parameters of the front-end power circuit, the voltage value corresponding to the voltage signal of a single lithium battery is clamped to near the preset constant voltage charging voltage target value.

[0042] During constant current and constant voltage charging, the charging current signal of a single lithium battery is continuously monitored. If the current value corresponding to the charging current signal of a single lithium battery decays to the preset charging termination current threshold, a stop signal is sent to the front-end power circuit and the fixed-frequency resonant TAB converter to terminate the charging closed loop.

[0043] Under low-voltage, high-current charging conditions, the charging closed-loop enhanced control is activated to shorten the sampling period of the voltage signal and charging current signal of a single lithium battery, thereby simultaneously improving the adjustment response speed of the output parameters of the front-end power circuit.

[0044] The present invention also provides a dual-input charging control device for a single-cell lithium battery, comprising:

[0045] The three-port detection module is used to detect the electrical parameters of the AC side port, photovoltaic side port and battery low-voltage side port to determine the current working mode;

[0046] The front-end power control module is used to control the active power factor correction circuit in AC charging mode to convert AC mains power into the first DC power; and in photovoltaic charging mode, it controls the photovoltaic maximum power point tracking boost circuit to boost the photovoltaic DC power into the second DC power.

[0047] The fixed-frequency resonant isolation module controls the primary-side active bridge switch to turn on and off at a fixed frequency, driving the fixed-frequency resonant TAB converter to resonate and reuse in three charging modes: AC, photovoltaic, and hybrid. The converter uses the transformer leakage inductance and resonant capacitor to form an equivalent LC series resonant circuit. The low-voltage side is a diode rectification and clamping circuit, and the magnetizing inductor only has dead-zone freewheeling current. The electrical energy on the high-voltage DC bus is isolated and converted into low-voltage high-current electrical energy by a high-frequency transformer, and then charged a single lithium battery through the battery-side port.

[0048] The charging management module is used to collect the voltage, current and temperature signals of the single lithium battery, control the front-end power control module to switch the charging path according to the collection results, and trigger a stop command when charging is completed or a fault occurs.

[0049] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the above-described method for dual-input charging control of a single-cell lithium battery.

[0050] Furthermore, the computer program is configured to execute in a power management chip or microcontroller and directly generate PWM control signals to control the active power factor correction circuit, the photovoltaic maximum power point tracking boost circuit, and the fixed-frequency resonant TAB converter. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the AC input side and high-voltage DC bus circuit of the present invention;

[0052] Figure 2 This is a schematic diagram of the fixed-frequency resonant TAB converter and bus connection of the present invention;

[0053] Figure 3 This is a schematic diagram of the photovoltaic MPPT boost circuit of the present invention;

[0054] Figure 4 This is a flowchart of the method for controlling dual-input charging of a single lithium battery using alternating light and electricity, according to the present invention.

[0055] Figure 5 This is a structural block diagram of the present invention for a dual-input charging control device for a single-cell lithium battery;

[0056] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0058] Reference Figure 4 This is a flowchart illustrating a dual-input charging control method for a single-cell lithium battery proposed in this invention, comprising the following steps:

[0059] S1, detect the electrical parameters of the AC side port, photovoltaic side port and battery low voltage side port to obtain the detection results, and determine the current working mode as any one of AC charging mode, photovoltaic charging mode and hybrid charging mode based on the detection results;

[0060] S2, if in the AC charging mode or hybrid charging mode, control the active power factor correction circuit connected to the AC side port to work and convert the AC mains power into the first DC power; if in the photovoltaic charging mode, control the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port to work and boost the photovoltaic DC power into the second DC power.

[0061] The first or second DC power is transmitted to a common high-voltage DC bus;

[0062] S3, control the preset fixed-frequency resonant TAB converter to work on the high-voltage DC bus at a fixed resonant frequency, and rectify the low-voltage side port of the battery through the high-frequency transformer built into the fixed-frequency resonant TAB converter to output electrical energy adapted to a single lithium battery.

[0063] The fixed-frequency resonant TAB converter is reused in each charging mode, and its operating frequency is fixed and does not use phase-shift control. The three-port architecture and the reuse design of the fixed-frequency resonant TAB converter are adapted to dual-input extreme application scenarios. The three-port architecture includes an AC side port, a photovoltaic side port and a battery low-voltage side port.

[0064] S4, adjust the output power according to the voltage and current of the single lithium battery to perform constant current charging or constant voltage charging closed loop.

[0065] As described in step S1 above, real-time operating status data of the two input sources are obtained by detecting the electrical status of the AC side port and the photovoltaic side port. Based on the detection results, the mode is classified: if only the AC side port meets the requirements for normal mains power connection and the parameters are up to standard, it is determined to be AC ​​charging mode; if only the voltage and current of the photovoltaic side port meet the operating requirements of the boost circuit, it is determined to be photovoltaic charging mode; if both ports meet the operating conditions and the electrical parameters do not conflict, and can simultaneously supply energy to the subsequent bus, it is determined to be hybrid charging mode. By accurately identifying the input status, decision support is provided for the targeted startup of the active power factor correction (PFC) circuit or the photovoltaic maximum power point tracking (MPPT) boost circuit in subsequent steps.

[0066] As described in step S2 above, based on the mode determination result of step S1, if the mode is determined to be AC ​​charging mode or hybrid mode, the active power factor correction (PFC) circuit connected to the AC side port is activated. This rectifies and optimizes the power factor of the AC mains input to the AC side port, converting it into a first DC power that conforms to the high-voltage DC bus specifications. If the mode is determined to be photovoltaic charging mode, the photovoltaic maximum power point tracking (MPPT) boost circuit connected to the photovoltaic side port is activated. Based on the output characteristics of a single photovoltaic panel, the boost control converts the photovoltaic DC power into a second DC power that matches the bus voltage. Both the first and second DC power after preprocessing in any mode are delivered to the shared high-voltage DC bus, achieving unified convergence of dual-source energy. By precisely controlling the preprocessing circuit according to the different modes, both efficient conversion of AC mains power and grid compatibility are ensured, as well as stable boosting of photovoltaic energy and bus compatibility are guaranteed.

[0067] As described in step S3 above, a unique fixed-frequency resonant TAB converter connected between the high-voltage DC bus and the battery side port completes the isolation conversion and adaptation of the high-voltage DC bus power, providing compliant charging energy for a single lithium battery. The fixed-frequency resonant TAB converter is controlled to operate at a fixed resonant frequency without phase-shift control. The active bridge switching transistors on the primary side of the converter are alternately turned on at a fixed resonant frequency, converting the DC power on the high-voltage DC bus into high-frequency AC power. The high-frequency AC power is excited to a resonant state through an equivalent LC series resonant network formed by the transformer leakage inductance and the resonant capacitor, achieving efficient energy transfer. The high-frequency transformer built into the converter achieves high and low voltage electrical isolation and voltage level matching between the AC side or photovoltaic side and the battery side. The AC-DC conversion is completed through the diode rectification structure on the low-voltage side of the battery, with clamping circuits limiting voltage spikes. During the dead-time phase of the switching transistor drive, the magnetizing inductor provides a current freewheeling path, assisting the primary-side switching transistor in achieving zero-voltage turn-on soft switching operation. Simultaneously, the diodes naturally turn off using the resonant current to reduce high-current conduction losses. This step reuses the same fixed-frequency resonant TAB converter, which fits the reuse design of the dual-source integrated topology, ensuring high efficiency, safety, and low-voltage high-current adaptability of energy conversion.

[0068] As described in step S4 above, real-time voltage and charging current data of a single lithium battery are collected as the basis for adjustment. Leveraging the fixed operating frequency of the fixed-frequency resonant TAB converter, the charging path switching is achieved by adjusting the output power of the PFC circuit or MPPT boost circuit's front-end power circuit: When the battery voltage is below a preset threshold, the output power of the front-end circuit is adjusted to maintain the charging current stable at the target value, executing constant current charging to quickly replenish battery energy; when the battery voltage rises to the preset threshold, the adjustment logic is switched, and the output voltage is adjusted through the front-end circuit to clamp the battery terminal voltage near the preset threshold, executing constant voltage charging, and the charging current naturally decays. The entire adjustment process ensures the continuous effectiveness of soft-switching technology and reduces energy loss while precisely matching the charging characteristics of a single lithium battery, achieving a smooth transition from constant current to constant voltage; when the charging current decays to a preset termination threshold during the constant voltage stage, or when faults such as overcurrent, overvoltage, or temperature exceeding limits are detected on the battery side, the front-end power circuit and the fixed-frequency resonant TAB converter stop working, ultimately completing a safe and efficient charging closed loop.

[0069] In one embodiment, step S1, which involves detecting electrical parameters at the AC side port, the photovoltaic side port, and the low-voltage side port of the battery to obtain detection results, and determining the current operating mode as any one of AC charging mode, photovoltaic charging mode, or hybrid charging mode based on the detection results, includes:

[0070] S11, Obtain the voltage signal of the AC side port and determine whether the AC mains power is properly connected and the parameters are valid;

[0071] S12, acquire the voltage and current signals of the photovoltaic side port to determine whether the photovoltaic panel has effective energy output;

[0072] S13. Based on the detection results of the two steps mentioned above, execute the preset logic rules and output the current working mode signal.

[0073] In practical implementation, the system immediately performs input source detection and mode determination after power-on. The system synchronously collects three analog signals from the AC side, photovoltaic side, and low-voltage battery side through its main control unit to determine the input status and battery status. For the AC side port AC-L / AC-N, a high-resistance voltage divider network resistor is connected between AC-L and AC-N. This voltage divider network is connected in series with the AC side port and the front end of the active power factor correction circuit. One end is connected to AC-L, and the other end is connected to AC-N. The middle tap is connected to the main control unit through a sampling line, forming a detection link of mains input → voltage divider attenuation → main control acquisition, which converts the high voltage of the mains into a low voltage sampling signal. This signal is connected to the analog-to-digital conversion channel of the main control unit. The main control unit calculates the effective value of the sampling signal. When the value is continuously within the preset effective voltage range of 85V to 265V, and the relay of the AC side port path is detected to be in the closed state, the system determines that the AC side port input is valid. For the PV+ / PV- ports on the photovoltaic side, a voltage divider circuit is connected between PV+ and PV-. This voltage divider circuit is connected in parallel between the input terminals of the PV-side ports and the PV maximum power point tracking (MPPT) boost circuit, and directly in parallel with the PV panel output. The sampled signal is then connected to the main control unit after passing through an isolation circuit, forming a detection link of PV output → proportional attenuation → main control acquisition. This proportionally attenuates the PV panel output voltage. The main control unit reads this voltage value through another analog-to-digital conversion channel. When this voltage value is consistently higher than the 15V PV start-up threshold and lower than the maximum allowable input voltage, the system determines that the PV-side port input is valid. Based on the above two independent valid determination signals, the main control unit executes its built-in logic decision: if only the AC-side port input is valid, the operating mode is set to AC charging mode; if only the PV-side port input is valid, the operating mode is set to PV charging mode; if both are valid, the operating mode is set to hybrid charging mode. This mode determination result will be used as a key parameter and directly transmitted to the subsequent power circuit control logic.

[0074] In one embodiment, if in the AC charging mode or hybrid charging mode, the active power factor correction circuit connected to the AC side port is controlled to operate, converting the AC mains power into a first DC power; if in the photovoltaic charging mode, the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port is controlled to operate, boosting the photovoltaic DC power into a second DC power; step S2, which transmits the first DC power or the second DC power to the common high-voltage DC bus, includes:

[0075] S21, Mode response and start / stop control of the preceding circuit;

[0076] S22, Branch power conversion and parameter control;

[0077] S23, DC power confluence.

[0078] In practical implementation, the system controls the operation of the corresponding front-end power conversion circuit based on the working mode determined in step S1, providing stable power to the shared high-voltage DC bus. When the system determines that it is in AC charging mode or hybrid charging mode, the main control unit generates a specific pulse width modulation signal to drive the active power factor correction circuit, which mainly consists of... Figure 2 The full-bridge switching transistors Q1, Q2, Q3, and Q4 in the circuit constitute a bridge. Figure 2 The core inverter bridge arm of the PFC circuit, shown in Figure 2, consists of the full-bridge switches Q1, Q2, Q3, and Q4. Q1 and Q2 are connected in series to form one bridge arm, and Q3 and Q4 are connected in series to form another bridge arm. These two bridge arms are connected in parallel across the AC rectified bus. The INV_PWM1 to INV_PWM4 signals drive the gates of the four switches respectively, achieving full-bridge rectification and power factor correction. Figure 2 The pulse width modulation signals INV_PWM1 to INV_PWM4 control the on / off timing of the circuit. The circuit operates in continuous conduction mode, rectifying the AC input while forcing the input current waveform to track the input voltage waveform, thereby converting the AC mains power into a stable high-voltage DC power. The DC voltage is controlled at a preset value of 400V, i.e., the first DC voltage. When the system determines it is in photovoltaic charging mode, the main control unit initiates another set of control logic, dynamically adjusting the maximum power point tracking algorithm. Figure 3 The duty cycles of the other pulse width modulation signals MPPT_PWM1 and MPPT_PWM2 are used in the maximum power point tracking algorithm. The algorithm employs a perturbation-observation method, periodically fine-tuning the duty cycles of MPPT_PWM1 and MPPT_PWM2 with a step size of 0.5%. It compares the changes in photovoltaic output power before and after the perturbation, dynamically tracking the maximum power point to ensure the photovoltaic panel continues to operate in its optimal output state under fluctuating light conditions. The algorithm adapts to the 40-63V output characteristics of a single photovoltaic panel, thereby controlling... Figure 3 In the photovoltaic maximum power point tracking (MPPT) boost circuit, the switching transistors Q7 and Q8, Q7 and Q8 are in Figure 3 The circuit forms a half-bridge topology for the MPPT boost circuit, connected in parallel with inductor L8 and the photovoltaic input terminal. MPPT_PWM1 and MPPT_PWM2 signals drive the gates of Q7 and Q8 respectively, achieving inductor energy storage and boost output through complementary switching. The output terminal is directly connected to the high-voltage DC bus. Figure 3 Inductor L8 stores and releases energy, boosting the fluctuating DC output from the photovoltaic panel to a voltage level matching the aforementioned high-voltage DC bus, i.e., the second DC current. The positive and negative output terminals of the DC current generated by any pre-amplifier circuit are directly connected to... Figure 1 The same group of high-voltage filter capacitors, this group of capacitors is connected in parallel. Figure 1The positive and negative terminals of the medium-voltage DC bus VBUS are directly connected in parallel with the output terminals of both the PFC and MPPT circuits, forming a bus link from PFC / MPPT output to capacitor filtering and then to bus voltage regulation. This provides a stable input for the subsequent fixed-frequency resonant TAB converter. This group of capacitors constitutes the shared high-voltage DC bus. In AC or photovoltaic single mode, only one circuit supplies power to this bus; in hybrid mode, both circuits can simultaneously inject power into the bus, and their outputs are... Figure 1 A parallel bus capacitor is implemented at the intermediate bus, providing a stable high-voltage DC power supply for the subsequent fixed-frequency resonant TAB converter, enabling the converter to be reused in different modes. In hybrid charging mode, the main control unit monitors the high-voltage DC bus voltage in real time through sampling of the bus voltage divider resistor. When the bus voltage is higher than the preset value of 400V ±5%, the output voltage gain of the PFC circuit is finely adjusted first; when the bus voltage is lower than this range, compensation is made by increasing the duty cycle of the MPPT boost circuit to ensure that the bus voltage is stable within the range of 400V ±2%, avoiding the abnormal operation of the fixed-frequency resonant TAB converter due to the conflict between the two input energy sources.

[0079] In one embodiment, step S3, which controls a preset fixed-frequency resonant TAB converter to operate the high-voltage DC bus at a fixed resonant frequency and performs rectification processing on the low-voltage side port of the battery through the high-frequency transformer built into the fixed-frequency resonant TAB converter to output electrical energy adapted to a single lithium battery, includes:

[0080] S31, primary-side active bridge switch transistor fixed-frequency drive and high-frequency inverter;

[0081] S32, Equivalent LC series resonant excitation and energy transfer;

[0082] S33, high-frequency transformer isolation conversion and voltage matching;

[0083] S34, low-voltage side diode rectification and clamping treatment for the battery.

[0084] In practice, the main control unit directs... Figure 2 The primary-side active bridge switch Q6 and other switches constituting the bridge arm of the fixed-frequency resonant TAB converter emit complementary pulse width modulation drive signals with a fixed resonant frequency. The drive signal frequency is fixed in the range of 80kHz to 91kHz, consistent with the inherent resonant frequency of the LC resonant network formed by the transformer leakage inductance and resonant capacitor, and phase-shift control is not used. The drive signal controls the switches to conduct alternately, turning on the circuit... Figure 2The DC current on the medium-voltage DC bus VBUS is converted into high-frequency AC current. This high-frequency AC current is applied to an equivalent LC series resonant circuit formed by the transformer leakage inductance (which acts as the sole resonant inductor) and resonant capacitors Cr1 and Cr2. This circuit is connected in series between the primary-side switching bridge arm of the fixed-frequency resonant TAB converter and the primary side of the built-in high-frequency transformer, forming an energy transmission link from primary-side inverter → equivalent LC resonant circuit → transformer primary side. The fixed-frequency resonant TAB converter integrates... Figure 2 The magnetizing inductor within the medium-to-high frequency transformer does not participate in the LC series resonance; it only functions during the dead-time phase of the switching transistor drive. The main control unit operates the resonant circuit in a purely resistive resonance state by fixing the drive frequency. During the dead-time phase of the switching transistor drive, the magnetizing inductor provides a current freewheeling path, assisting the primary-side switching transistor in achieving zero-voltage turn-on soft switching, significantly reducing switching losses. The primary side of the transformer is connected to the output terminal of the resonant circuit, and the secondary side of the high-frequency transformer is connected to... Figure 1 The diode rectifier structure achieves high- and low-voltage electrical isolation between the AC side or photovoltaic side and the battery side through winding isolation. Its turns ratio is 64:12:1:1:1:1 to match voltage conversion requirements, proportionally converting high-voltage AC power to low-voltage AC power suitable for charging a single lithium battery. On the secondary side of the transformer, the system... Figure 1 The low-voltage side diode rectifier structure Q11 and Q12 of the medium-voltage battery completes the AC-DC conversion: this structure is connected in parallel across the secondary side of the transformer, and... Figure 1 In this configuration, the single-cell lithium battery load (Bat+ and Bat-) is directly connected, forming a low-voltage side link from the transformer secondary to the diode rectification to the battery load. No filter capacitor is included. Figure 1 The battery load and diode form a clamping circuit to limit voltage spikes and prevent voltage surges at the lithium battery terminals. The diode's conduction and turn-off rely on resonant current characteristics: when the transformer secondary voltage is positive, the corresponding diode conducts, rectifying the AC power into unidirectional DC; during the dead-time phase of the switching transistor drive, the diode naturally turns off using the resonant current, reducing high-current conduction losses. The energy on the high-voltage DC bus originates from the AC PFC circuit or photovoltaic MPPT circuit in step S2. Subsequent isolation conversion and rectification are all completed by the same fixed-frequency resonant TAB converter hardware. Its operating frequency is fixed, and the hardware connections and resonant parameters remain unchanged. Only the output power is adjusted by the front-end power circuit to adapt to charging needs, achieving complete multiplexing of the converter in different modes.

[0085] In one embodiment, step S4, which adjusts the output power according to the voltage and current of the single lithium battery to perform a constant current charging or constant voltage charging closed loop, includes:

[0086] S41, real-time acquisition of battery status parameters;

[0087] S42, logic judgment during charging phase;

[0088] S43, constant current charging closed-loop control;

[0089] S44, constant voltage charging closed-loop control;

[0090] S45, Charging Termination and Safety Monitoring.

[0091] In the specific implementation process, the system acquires key parameters through two independent detection circuits. One circuit is a battery voltage sampling circuit, which is connected in parallel with... Figure 1 The positive and negative terminals of a single lithium battery are connected to... Figure 1 The output of the charging circuit at the battery side port is connected in parallel. The sampled signal is isolated by a linear optocoupler and then connected to the ADC channel of the main control unit, forming a detection link of battery voltage → linear attenuation → isolated transmission → main control acquisition. This linearly attenuates the battery voltage in the 0-4.2V range to the 0-3.3V input range of the main control unit's analog-to-digital converter (ADC). The other path is a charging current sampling circuit, which is connected in series with... Figure 1 The output terminal of the low-voltage side diode rectifier structure Q11 in the medium-voltage battery is connected in series with the positive electrode Bat+ of the lithium battery. Figure 1In the main charging circuit, current detection is achieved through a combination of a precision sampling resistor and a differential amplifier: the differential amplifier is connected in parallel across the sampling resistor, converting the current signal into a voltage signal and transmitting it to the ADC channel of the main control unit to complete the real-time acquisition of the charging current. The charging algorithm compares the continuously acquired battery voltage value with a preset charging cutoff voltage threshold. For a single lithium iron phosphate battery, this threshold is typically set to 3.65V. When the real-time battery voltage is lower than this threshold, the algorithm enters the constant current CC charging stage. In this stage, the algorithm compares the real-time acquired charging current value with the preset constant current target value, and dynamically adjusts the output power of the front-end power circuit, i.e., the AC side PFC circuit or the photovoltaic side MPPT boost circuit, through a proportional-integral (PI) controller. Utilizing the fixed operating frequency of the fixed-frequency resonant TAB converter, the charging current is precisely stabilized at the target value. When the battery voltage reaches or exceeds the preset threshold of 3.65V, the charging phase switches to the constant-voltage CV charging phase. At this point, the control objective becomes stabilizing the battery voltage. The algorithm compares the collected battery voltage with the 3.65V target voltage, and the error signal is converted by the PI controller into an adjustment command for the output voltage of the front-end power circuit, precisely clamping the battery terminal voltage near the cutoff voltage. The charging current naturally decreases as the battery is fully charged. The system continuously monitors the charging current during the constant-voltage phase. When the current decreases to a preset charging termination threshold, such as 0.05C, the main control unit determines that the battery is fully charged, stops the operation of the front-end power circuit and the fixed-frequency resonant TAB converter, and ends the charging cycle. Throughout the entire S4 process, if the charging current exceeds the safety limit, the battery voltage is abnormal, or the temperature exceeds the limit as detected by the NTC thermistor attached to the battery surface, the main control unit immediately performs a protective shutdown, cutting off the energy transfer path.

[0092] Reference Figure 5 Here is a structural block diagram of a control device for a single-cell lithium battery with dual optical and electrical inputs, according to an embodiment of the present invention, comprising:

[0093] The three-port detection module is used to detect the electrical parameters of the AC side port, photovoltaic side port and battery low-voltage side port to determine the current working mode;

[0094] The front-end power control module is used to control the active power factor correction circuit in AC charging mode to convert AC mains power into the first DC power; and in photovoltaic charging mode, it controls the photovoltaic maximum power point tracking boost circuit to boost the photovoltaic DC power into the second DC power.

[0095] The fixed-frequency resonant isolation module controls the primary-side active bridge switch to turn on and off at a fixed frequency, driving the fixed-frequency resonant TAB converter to resonate and reuse in three charging modes: AC, photovoltaic, and hybrid. The converter uses the transformer leakage inductance and resonant capacitor to form an equivalent LC series resonant circuit. The low-voltage side is a diode rectification and clamping circuit, and the magnetizing inductor only has dead-zone freewheeling current. The electrical energy on the high-voltage DC bus is isolated and converted into low-voltage high-current electrical energy by a high-frequency transformer, and then charged a single lithium battery through the battery-side port.

[0096] The charging management module is used to collect the voltage, current and temperature signals of the single lithium battery, control the front-end power control module to switch the charging path according to the collection results, and trigger a stop command when charging is completed or a fault occurs.

[0097] In summary, this invention constructs a three-port architecture on the AC side, photovoltaic side, and battery side. First, it detects the electrical status of the AC side and photovoltaic side ports to determine the operating mode. Based on the mode, it controls the corresponding front-end power circuit. In AC or mixed operating modes, the active power factor correction circuit on the AC side port is activated, and in photovoltaic mode, the photovoltaic maximum power point tracking (MPPT) boost circuit on the photovoltaic side port is activated. The electrical energy output from both is converged to a shared high-voltage DC bus. The only fixed-frequency resonant TAB converter connected between the bus and the battery side port is controlled to operate at a fixed resonant frequency. This converter uses the transformer leakage inductance as the only resonant inductor, and together with the resonant capacitor, it forms an equivalent LC series resonant circuit. The magnetizing inductor does not participate in the resonance and only freewheels during the dead time of the switching transistor. After high-low voltage isolation and voltage matching are achieved by its built-in high-frequency transformer, the output is processed by the low-voltage side diode rectification and the unfiltered capacitor clamping circuit to output adapted electrical energy. Finally, based on the voltage and current signals of a single lithium battery, the output power is adjusted by the front-end power circuit to achieve a constant current and constant voltage charging closed loop, and charging termination and safety monitoring are performed simultaneously.

[0098] In this embodiment, the specific implementation of each unit in the above device embodiment is described in the above method embodiment, and will not be repeated here.

[0099] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the present invention and embodiments can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual-rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM, etc.

[0100] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0101] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for controlling dual-input charging of a single lithium battery, characterized in that, Includes the following steps: The electrical parameters of the AC side port, photovoltaic side port and battery low-voltage side port are detected to obtain the detection results. Based on the detection results, the current working mode is determined to be any one of AC charging mode, photovoltaic charging mode and hybrid charging mode. If in the AC charging mode or hybrid charging mode, the active power factor correction circuit connected to the AC side port is controlled to work and convert the AC mains power into the first DC power; if in the photovoltaic charging mode, the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port is controlled to work and boost the photovoltaic DC power into the second DC power. The first or second DC power is transmitted to a common high-voltage DC bus; The preset fixed-frequency resonant TAB converter operates the high-voltage DC bus at a fixed resonant frequency, and the low-voltage side port of the battery is rectified by the high-frequency transformer built into the fixed-frequency resonant TAB converter to output electrical energy adapted to a single lithium battery. The fixed-frequency resonant TAB converter is reused in each charging mode, and its operating frequency is fixed and does not use phase-shift control. The three-port architecture and the reuse design of the fixed-frequency resonant TAB converter are adapted to dual-input extreme application scenarios. The three-port architecture includes an AC side port, a photovoltaic side port and a battery low-voltage side port. The output power is adjusted according to the voltage and current of the single lithium battery cell to perform constant current charging or constant voltage charging closed loop. The fixed-frequency resonant TAB converter uses the transformer leakage inductance as the only resonant inductor, and together with the resonant capacitor, it forms an equivalent LC series resonant circuit. The equivalent LC series resonant circuit has a fixed resonant frequency. Furthermore, the magnetizing inductor in the fixed-frequency resonant TAB converter does not participate in the LC series resonance, but only provides a freewheeling path for the current during the dead time of the switching transistor drive. The freewheeling path is used to stabilize the energy transmission of the high-voltage DC bus.

2. The method for dual-input charging control of a single lithium battery according to claim 1, characterized in that, The steps of the fixed-frequency resonant TAB converter using the transformer leakage inductance as the sole resonant inductor and forming an equivalent LC series resonant circuit with the resonant capacitor include: The active bridge switching transistors on the primary side of the fixed-frequency resonant TAB converter are controlled to conduct alternately at a fixed resonant frequency, converting the DC power on the high-voltage DC bus into high-frequency AC power. The high-frequency AC power is then excited into a resonant state through an LC series resonant network. The high-frequency transformer is used to achieve high and low voltage electrical isolation and voltage level matching in a three-port architecture. The diode rectifier structure at the low-voltage side port of the battery performs AC-DC conversion to limit voltage spikes in conjunction with the clamping circuit. During the dead-time phase of the signal-bound switching transistor driven by the clamping circuit that limits voltage spikes, the magnetizing inductor provides a freewheeling path to assist the primary-side switching transistor in performing a soft-switching operation with zero voltage turn-on. At the same time, the diode is naturally turned off using the resonant current.

3. The method for dual-input charging control of a single lithium battery according to claim 1, characterized in that, The steps for fixing the resonant frequency of the equivalent LC series resonant circuit include: Based on the fixed-frequency resonant TAB converter, the resonant parameter matching relationship of the equivalent LC series resonant circuit is derived using the target value of the fixed resonant frequency, and the matching range of the transformer leakage inductance and the selection range of the resonant capacitor value are determined. The actual leakage inductance value of the built-in high-frequency transformer of the fixed-frequency resonant TAB converter is detected. After eliminating measurement errors, a resonant capacitor matching the actual leakage inductance value is selected from the preset capacitance selection range. The selected resonant capacitor is connected to the leakage inductance of the high-frequency transformer to form an equivalent LC series resonant circuit, so that the inherent resonant frequency of the circuit is consistent with the preset fixed resonant frequency target value. Start the fixed-frequency resonant TAB converter, and collect the voltage and current signals of the equivalent LC series resonant circuit in real time. The circuit resonance state is determined by signal analysis. If the inherent resonant frequency of the circuit is detected to deviate from the preset target value, compensation and calibration are performed by fine-tuning the capacitance value of the resonant capacitor until the circuit operates stably at the preset fixed resonant frequency.

4. The method for dual-input charging control of a single lithium battery according to claim 1, characterized in that, The magnetizing inductor in the fixed-frequency resonant TAB converter does not participate in the LC series resonance, and only provides a freewheeling path for the current during the dead time of the switching transistor drive, including: The actual parameters of the magnetizing inductance of the built-in high-frequency transformer of the fixed-frequency resonant TAB converter are detected, and the range of the dead time of the switch drive is set based on the actual parameters to ensure that the dead time matches the energy storage characteristics of the magnetizing inductance. Configure the freewheeling circuit of the magnetizing inductor so that the freewheeling circuit is turned on only during the dead time phase of the switch tube drive and turned off during the non-dead time phase, so as to avoid the magnetizing inductor participating in the resonance process of the equivalent LC series resonant circuit. When the fixed-frequency resonant TAB converter is started, the freewheeling current waveform of the magnetizing inductor is monitored in real time during the dead zone of the switching transistor drive. If the freewheeling current is detected to be interrupted or fluctuate beyond a preset threshold, the dead time parameter of the switch driver is adjusted to ensure that the freewheeling path is continuously and stably connected. The resonance state of the equivalent LC series resonant circuit was monitored synchronously to verify that the freewheeling action of the magnetizing inductor did not interfere with the fixed resonant frequency of the resonant circuit.

5. The method for controlling dual-input charging of a single lithium battery according to claim 1, characterized in that, The step of controlling the active power factor correction circuit connected to the AC side port to operate and convert AC mains power into first DC power when in AC charging mode or hybrid charging mode includes: The active power factor correction circuit is activated and connected to a wide range of AC mains power on the AC side port. The power factor correction adjustment logic is implemented to control the on / off timing of the full-bridge switching transistors in the active power factor correction circuit, so that the input current waveform tracks the input voltage waveform. The voltage signal of the high-voltage DC bus is acquired, and the power factor correction regulation logic is dynamically adjusted according to the voltage signal to stabilize the power energy after power factor correction and output the first DC power to the high-voltage DC bus. In the hybrid charging mode, the output status signal of the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port is synchronously acquired. Based on the output status signal and the high voltage DC bus voltage signal, the on / off timing of the full-bridge switching transistors and the output adjustment parameters of the active power factor correction circuit are synchronously adjusted.

6. The method for controlling dual-input charging of a single lithium battery according to claim 1, characterized in that, The step of adjusting the output power according to the voltage and current of the single lithium battery to perform a constant current charging or constant voltage charging closed loop includes: The constant current charging current target value, constant voltage charging voltage target value, and charging termination current threshold value are preset for the fixed frequency resonant TAB converter. The voltage and current signals of the single lithium battery are collected in real time, and the current output power signals of the active power factor correction circuit connected to the AC side port and the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port are collected simultaneously. The active power factor correction circuit connected to the AC side port and the photovoltaic maximum power point tracking boost circuit connected to the photovoltaic side port together constitute the front-end power circuit. Compare the collected voltage signal of a single lithium battery cell with the preset constant voltage charging voltage target value: If the voltage value corresponding to the voltage signal of a single lithium battery cell is lower than the constant voltage charging voltage target value, execute constant current charging control, and adjust the output parameters of the front-end power circuit to stabilize the current value corresponding to the charging current signal of a single lithium battery cell at the preset constant current charging current target value. When the voltage value corresponding to the voltage signal of a single lithium battery reaches or exceeds the preset constant voltage charging voltage target value, the system switches to constant voltage charging control. By adjusting the output parameters of the front-end power circuit, the voltage value corresponding to the voltage signal of a single lithium battery is clamped to near the preset constant voltage charging voltage target value. During constant current and constant voltage charging, the charging current signal of a single lithium battery is continuously monitored. If the current value corresponding to the charging current signal of a single lithium battery decays to the preset charging termination current threshold, a stop signal is sent to the front-end power circuit and the fixed-frequency resonant TAB converter to terminate the charging closed loop. Under low-voltage, high-current charging conditions, the charging closed-loop enhanced control is activated to shorten the sampling period of the voltage signal and charging current signal of a single lithium battery, thereby simultaneously improving the adjustment response speed of the output parameters of the front-end power circuit.

7. A dual-input charging control device for a single-cell lithium battery, characterized in that, The apparatus for performing the dual-input charging control method for a single-cell lithium battery as described in any one of claims 1 to 6, the apparatus comprising: The three-port detection module is used to detect the electrical parameters of the AC side port, photovoltaic side port and battery low-voltage side port to determine the current working mode; The front-end power control module is used to control the active power factor correction circuit in AC charging mode to convert AC mains power into the first DC power; and in photovoltaic charging mode, it controls the photovoltaic maximum power point tracking boost circuit to boost the photovoltaic DC power into the second DC power. The fixed-frequency resonant isolation module controls the primary-side active bridge switch to turn on and off at a fixed frequency, driving the fixed-frequency resonant TAB converter to resonate and reuse in three charging modes: AC, photovoltaic, and hybrid. The converter uses the transformer leakage inductance and resonant capacitor to form an equivalent LC series resonant circuit. The low-voltage side is a diode rectification and clamping circuit, and the magnetizing inductor only has dead-zone freewheeling current. The electrical energy on the high-voltage DC bus is isolated and converted into low-voltage high-current electrical energy by a high-frequency transformer, and then charged a single lithium battery through the battery-side port. The charging management module is used to collect the voltage, current and temperature signals of the single lithium battery, control the front-end power control module to switch the charging path according to the collection results, and trigger a stop command when charging is completed or a fault occurs.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the dual-input charging control method for a single-cell lithium battery as described in any one of claims 1 to 6.

9. The computer-readable storage medium according to claim 8, characterized in that, The computer program is configured to execute in a power management chip or microcontroller and directly generate PWM control signals to control the active power factor correction circuit, the photovoltaic maximum power point tracking boost circuit, and the fixed-frequency resonant TAB converter.

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